JP5391538B2 - Manufacturing method of liquid crystal display element - Google Patents

Description

  The present invention relates to a method of manufacturing a liquid crystal display element using monostable ferroelectric liquid crystal having spontaneous polarization.

  Liquid crystal display elements have been widely used from large displays to portable information terminals because of their thinness and low power consumption, and their development is actively underway. So far, liquid crystal display elements have been developed and put to practical use, such as TN mode, STN multiplex drive, and active matrix drive using thin layer transistors (TFTs) for TN, but these use nematic liquid crystals. In addition, the response speed of the liquid crystal material is as slow as several ms to several tens of ms, and it cannot be said that it is sufficiently compatible with moving image display.

  Ferroelectric liquid crystal (FLC) is a liquid crystal suitable for high-speed devices because its response speed is as short as μs order. Ferroelectric liquid crystals proposed by Clark and Lagerwol are widely known to be bistable having two stable states when no voltage is applied (FIG. 20 top), but for switching in two states, bright and dark. Although it has limited memory characteristics, it has a problem that gradation display cannot be performed.

In recent years, the state of the liquid crystal layer when no voltage is applied is stabilized in a single state (hereinafter referred to as “monostable”). ) Is continuously changed, and the transmitted light intensity is analog-modulated so that gradation display is possible (see Non-Patent Document 1, lower part of FIG. 20). As the liquid crystal exhibiting monostability, generally, a ferroelectric liquid crystal that changes phase with the cholesteric phase (Ch) -chiral smectic C (SmC ^* ) phase in the temperature lowering process and does not pass through the smectic A (SmA) phase is used ( FIG. 13 top).

On the other hand, the ferroelectric liquid crystal is a material that changes in phase with a cholesteric phase (Ch) -smectic A (SmA) phase-chiral smectic C (SmC ^* ) phase in the temperature lowering process and exhibits an SmC ^* phase via the SmA phase. There is. Most of the ferroelectric liquid crystal materials currently reported have a phase series that passes through the latter SmA phase compared to the former material that does not pass through the SmA phase. It is known that a ferroelectric liquid crystal having a phase sequence passing through the latter SmA phase usually has two stable states with respect to a single-layer normal (lower stage in FIG. 13) and exhibits bistability. .

  In recent years, color liquid crystal display elements have been actively developed. As a method for realizing color display, there are generally a color filter method and a field sequential color method. In the color filter system, a white light source is used as a backlight, and color display is realized by attaching R, G, B micro color filters to each pixel. On the other hand, the field sequential color system switches the backlight to R, G, B, R, G, B ... in time, and opens and closes the black and white shutter of the ferroelectric liquid crystal to synchronize with it, and the afterimage effect of the retina Thus, the colors are mixed temporally to realize color display. In this field sequential color system, color display is possible with one pixel, and it is not necessary to use a color filter with low transmittance. Therefore, bright and high-definition color display is possible, and low power consumption and low cost can be realized. Useful in terms.

  In the field sequential color system, one pixel is time-divided, so that a liquid crystal as a black and white shutter needs to have high-speed response in order to obtain good moving image display characteristics. If a ferroelectric liquid crystal is used, this problem can be solved. As the ferroelectric liquid crystal used in this case, it is particularly desirable that the ferroelectric liquid crystal exhibits monostability in order to enable gradation display by analog modulation as described above and to realize high-definition color display. In addition, there are two types of ferroelectric liquid crystal exhibiting monostability, one that responds to positive and negative polarities (lower right in FIG. 20) and one that responds only to positive and negative polarities (lower left in FIG. 20). is there. In particular, when a ferroelectric liquid crystal is driven using a thin film transistor (TFT) element, it is particularly preferable to respond to a voltage of either positive or negative polarity because the influence of reversal current due to spontaneous polarization is small.

  Here, FIG. 21 shows an example of a driving sequence of a liquid crystal display element by a field sequential color method using TFT elements. In FIG. 21, it is assumed that the voltage applied to the liquid crystal display element is 0 to ± V (V), data writing scanning is performed with a positive polarity voltage, and data erasing scanning is performed with a negative polarity voltage. It is assumed that a ferroelectric liquid crystal that exhibits monostability and responds only to a positive or negative voltage is used.

  As a response of the ferroelectric liquid crystal which shows monostability and responds only to a voltage of either positive or negative polarity, as illustrated in FIG. 12 (a)) and a case where a bright state is obtained in response to a negative polarity voltage (FIG. 12 (b)). Therefore, as shown in FIG. 21, when the ferroelectric liquid crystal showing the response (liquid crystal response 1) of FIG. 12A is used, a bright state is obtained when a positive polarity voltage is applied, and FIG. When a ferroelectric liquid crystal exhibiting a response (liquid crystal response 2) is used, a bright state is obtained when a negative polarity voltage is applied.

The ferroelectric liquid crystal using the TFT element is driven by applying a constant voltage to the common electrode of the common electrode substrate facing the TFT substrate and applying a voltage to the pixel electrode of each pixel of the TFT substrate. Here, when the pixel electrode voltage is relatively high with respect to the common electrode, a positive polarity voltage application is applied, and when the pixel electrode voltage is relatively low, a negative polarity voltage application is applied.
When using a ferroelectric liquid crystal that responds only to positive polarity voltage, positive polarity voltage application (writing) and negative polarity voltage application (erasing) are alternated to balance the charge. To do. When a TFT element is used, voltage cannot be written to all pixels at the same time, so scanning is performed for each line. Therefore, the writing of the first line and the writing of the L line are out of timing. The same applies to erasure. In the example shown in FIG. 21, erasure is performed from the first line after writing of all lines is completed.
Further, in the field sequential color method, writing and erasing are performed in synchronization with the flashing of the backlight. In FIG. 21, + (R) indicates that the writing scan (application of a positive polarity voltage) is performed in synchronization with the R (red) backlight, and-(R) indicates that synchronization with the R backlight. This indicates that erase scanning (application of a negative polarity voltage) was performed. Similarly, + (G), − (G), + (B), and − (B) indicate that scanning is performed in synchronization with the backlights of G (green) and B (blue), respectively.

As described above, in the field sequential color system, the ferroelectric liquid crystal is made to respond by performing the write scan and the erase scan in synchronization with the temporal switching of the backlight R, G, B. When scanning in synchronism, if a ferroelectric liquid crystal showing a liquid crystal response 1 is used, the writing scan of the first line (+ (R)) and the writing scan of the L line (+ (R)) are performed. In any case, a bright state is obtained while the R backlight is lit. On the other hand, when the ferroelectric liquid crystal showing the liquid crystal response 2 is used, the write scan (+ (R)) and the erase scan (− (R)) are shifted in time between the first line and the L line. The erase scan (-(R)) on the L-th line synchronized with the R backlight results in a bright state when the G backlight is turned on (thick frame in FIG. 21). Further, when scanning in synchronization with the G backlight, the L-line erasing scan (-(G)) synchronized with the G backlight results in a bright state when the B backlight is turned on. (Thick frame in FIG. 21).
In FIG. 21, bright (R) indicates that a bright state is achieved by scanning synchronized with an R (red) backlight, and dark indicates R (red), G (green), and B (blue). ) Indicates a dark state by scanning synchronized with each backlight. Similarly, bright (G) and bright (B) are also shown to be in a bright state by scanning synchronized with G (green) and B (blue) backlights, respectively.

  In a normal liquid crystal display device, it is determined which of the positive polarity voltage and the negative polarity voltage is used for writing scanning or erasing scanning and cannot be easily changed. In order to avoid this, it is necessary to match the polarity of the voltage to which the ferroelectric liquid crystal exhibiting monostability responds to the polarity of the applied voltage. Since the response of the ferroelectric liquid crystal is determined by the direction of spontaneous polarization of the ferroelectric liquid crystal, the polarity of the voltage to which the ferroelectric liquid crystal responds can be controlled if the direction of spontaneous polarization can be controlled. .

  Ferroelectric liquid crystals are difficult to align because they have higher molecular ordering than nematic liquid crystals. In particular, in a ferroelectric liquid crystal that does not pass through the SmA phase, two regions having different layer normal directions (hereinafter referred to as “double domain”) are generated (the upper part of FIG. 13). Such a double domain becomes a serious problem because black-and-white inversion is displayed during driving. For this reason, various alignment processing methods have been studied.

  For example, as a method for improving the double domain, an electric field applied slow cooling method is known in which a liquid crystal cell is heated to a temperature equal to or higher than the cholesteric phase and gradually cooled while a DC voltage is applied (see Non-Patent Document 2). When this electric field application annealing method is used, the direction of spontaneous polarization can be controlled by the direction of the applied electric field. However, in this method, if the temperature rises again above the phase transition point, alignment disturbance occurs, and the manufacturing process becomes complicated, and alignment disturbance occurs in a portion where the electric field between the pixel electrodes does not act. There's a problem.

  Further, as a method for monostabilizing the ferroelectric liquid crystal, a method is proposed in which photo-alignment films are used as upper and lower alignment films, and materials having different compositions are used for these photo-alignment films (Patent Document 1, Patent). Reference 2 and Patent Document 3). In this method, the reason why a good alignment state can be obtained by using materials having different compositions for the upper and lower photo-alignment films is not clear, but the interaction between the upper and lower photo-alignment films and the ferroelectric liquid crystal is different. It is thought to be due to. However, in the liquid crystal display element obtained by this method, the direction of spontaneous polarization of the ferroelectric liquid crystal cannot be known unless it is actually driven.

  Furthermore, as another method for monostabilizing the ferroelectric liquid crystal, a reactive liquid crystal layer is formed on one of the upper and lower alignment films by applying and aligning the reactive liquid crystal, and this reaction is performed. Has been proposed (see Patent Document 4). In this method, the reactive liquid crystal is relatively similar in structure to the ferroelectric liquid crystal, so that the interaction with the ferroelectric liquid crystal becomes stronger, so that the alignment is more effective than when only the alignment film is used. By forming the reactive liquid crystal layer on one of the upper and lower alignment films, the ferroelectric liquid crystal can be aligned without causing alignment defects such as double domains. However, even in the liquid crystal display element obtained by this method, the direction of spontaneous polarization of the ferroelectric liquid crystal cannot be known unless it is actually driven.

JP 2005-208353 A JP 2005-234549 A JP 2005-234550 A JP 2005-258428 A NONAKA, T., LI, J., OGAWA, A., HORNUNG, B., SCHMIDT, W., WINGEN, R., and DUBAL, H., 1999, Liq. Cryst., 26, 1599. PATEL, J., and GOODBY, J. W., 1986, J. Appl. Phys., 59, 2355.

  The present invention has been made in view of the above problems, and a liquid crystal display element capable of controlling the direction of spontaneous polarization of a ferroelectric liquid crystal when a ferroelectric liquid crystal exhibiting monostability is used. The main purpose is to provide a manufacturing method.

  In order to achieve the above object, the present invention provides a ferroelectric liquid crystal on the first alignment film of the liquid crystal side substrate in which the first electrode layer and the first alignment film are laminated in this order on the first base material. A liquid crystal coating step of coating, a liquid crystal side substrate coated with the ferroelectric liquid crystal, and a substrate bonding step of bonding a counter substrate having a second electrode layer formed on the second base material; When the ferroelectric liquid crystal exhibits monostability and a voltage is applied so that the first electrode layer is a negative electrode, the molecular direction of the ferroelectric liquid crystal is relative to the liquid crystal side substrate surface. There is provided a method for manufacturing a liquid crystal display element, characterized in that it changes in parallel approximately twice the tilt angle of the ferroelectric liquid crystal.

  According to the present invention, the direction of the spontaneous polarization of the ferroelectric liquid crystal is controlled by utilizing the tendency of the spontaneous polarization of the ferroelectric liquid crystal to be directed to the counter substrate side on which the ferroelectric liquid crystal is not applied. It is possible to monostabilize the alignment of the ferroelectric liquid crystal. Accordingly, it is possible to avoid problems as described in the background art section above.

  In the above invention, the liquid crystal side substrate preparation step for preparing the liquid crystal side substrate is performed before the liquid crystal application step, and the liquid crystal side substrate preparation step fixes the reactive liquid crystal on the first alignment film. It is preferable to have a reactive liquid crystal layer forming step of forming a reactive liquid crystal layer, and to apply the ferroelectric liquid crystal on the reactive liquid crystal layer in the liquid crystal application step. By forming the reactive liquid crystal layer on the first alignment film, the reactive liquid crystal can be aligned by the first alignment film, and the reactive liquid crystal layer can act as an alignment film for aligning the ferroelectric liquid crystal. In addition, reactive liquid crystals are relatively similar in structure to ferroelectric liquid crystals, so they interact strongly with ferroelectric liquid crystals and effectively control the direction of spontaneous polarization of ferroelectric liquid crystals. Can do.

  In this case, the first alignment film is preferably a rubbing film that has been subjected to a rubbing treatment. This is because the use of a rubbing film for the first alignment film can effectively suppress the occurrence of zigzag defects and hairpin defects.

  In the present invention, a liquid crystal side substrate preparation step for preparing the liquid crystal side substrate is performed before the liquid crystal application step, and the liquid crystal side substrate preparation step forms the first alignment film on the first electrode layer. It is also preferable to have a first alignment film forming step, and in the first alignment film forming step, the first alignment film is formed by a photo-alignment process. This is because, when the first alignment film is subjected to photo-alignment treatment, the direction of spontaneous polarization of the ferroelectric liquid crystal can be effectively controlled. In addition, since the photo-alignment process is a non-contact alignment process, there is no generation of static electricity or dust, and the quantitative alignment process can be controlled.

  Further, in the present invention, the liquid crystal side substrate preparation step for preparing the liquid crystal side substrate is performed before the liquid crystal application step, and the liquid crystal side substrate preparation step forms a partition wall on the first base material. And a first alignment film forming step of forming the first alignment film on the first base material on which the partition walls and the first electrode layer are formed. When the ferroelectric liquid crystal flows on the first alignment film in an isotropic phase state by applying the ferroelectric liquid crystal to the liquid crystal side substrate on which the partition walls are formed in the liquid crystal application step, the ferroelectricity This is because the flow distance of the liquid crystal can be shortened and alignment disorder can be prevented from occurring at the contact interface of the flowing ferroelectric liquid crystal. Further, by applying the ferroelectric liquid crystal to the liquid crystal side substrate on which the partition walls are formed, it is possible to prevent uneven application, and to suppress the occurrence of uneven alignment due to uneven application.

  In the present invention, the counter substrate preparation step of preparing the counter substrate is performed before the substrate bonding step, and the counter substrate preparation step forms a second alignment film on the second electrode layer. It is preferable to have an alignment film forming step. When the second alignment film is formed on the counter substrate, since the ferroelectric liquid crystal is sandwiched between the first alignment film and the second alignment film, the alignment of the ferroelectric liquid crystal is stabilized. It is.

  In this case, it is preferable that the second alignment film is formed by a photo-alignment process in the second alignment film formation step. As described above, since the photo-alignment process is a non-contact alignment process, no static electricity or dust is generated, and the quantitative alignment process can be controlled.

  Furthermore, in the present invention, after the ferroelectric liquid crystal is heated to a temperature at which the ferroelectric liquid crystal exhibits a nematic phase or an isotropic phase in the liquid crystal coating step, and the liquid crystal side substrate is set to room temperature. It is preferable to apply the ferroelectric liquid crystal on the first alignment film by a discharge method. By applying the ferroelectric liquid crystal in this way, the ferroelectric liquid crystal can be discharged stably, the deterioration of the ferroelectric liquid crystal during the liquid crystal application can be suppressed, and further the ferroelectric liquid crystal This is because it is possible to suppress alignment disturbance when flowing on the first alignment film.

  At this time, the discharge method is preferably an ink jet method. This is because, if the inkjet method is used, the ferroelectric liquid crystal can be applied in a continuous manner, and the alignment disorder when the ferroelectric liquid crystal flows on the first alignment film can be effectively suppressed. .

  The present invention also includes a first substrate, a first electrode layer and a partition formed on the first substrate, a first alignment film formed on the first electrode layer and the partition, and the first A liquid crystal side substrate having a reactive liquid crystal layer formed on one alignment film and fixing a reactive liquid crystal, a second base material, a second electrode layer formed on the second base material, and A counter substrate formed on the second electrode layer and having a second alignment film which is a photo-alignment film containing a photodimerization type material or a photoisomerization type material, and the reactive liquid crystal layer of the liquid crystal side substrate and the counter electrode A liquid crystal layer including a ferroelectric liquid crystal formed between the second alignment film of the substrate, the ferroelectric liquid crystal exhibiting monostability, and the first electrode layer serving as a negative electrode When a voltage is applied to the ferroelectric liquid crystal, the ferroelectric liquid crystal has a molecular direction parallel to the liquid crystal side substrate surface. To provide a liquid crystal display element, characterized in that the changed by about 2 times the tilt angle.

  According to the present invention, the partition is formed on the liquid crystal side substrate, and when the liquid crystal display element of the present invention is manufactured, the alignment between the liquid crystal side substrate and the counter substrate is easy. Usually, the ferroelectric liquid crystal is applied to the liquid crystal side substrate on which the partition walls are formed. Therefore, as described above, it is possible to control the direction of the spontaneous polarization of the liquid crystal molecules by utilizing the tendency of the spontaneous polarization of the ferroelectric liquid crystal to face the opposite substrate side on which the ferroelectric liquid crystal is not applied. Is possible. Further, according to the present invention, the reactive liquid crystal layer is formed on the first alignment film in the liquid crystal side substrate, and the second alignment film is the predetermined photo-alignment film in the counter substrate. The direction of polarization can be controlled effectively.

  In the above invention, the first alignment film is preferably a rubbing film that has been subjected to a rubbing treatment. This is because the use of a rubbing film for the first alignment film can effectively suppress the occurrence of zigzag defects and hairpin defects.

  In the present invention, by applying the ferroelectric liquid crystal on the first alignment film of the liquid crystal side substrate, the spontaneous polarization of the ferroelectric liquid crystal tends to be directed to the counter substrate side where the ferroelectric liquid crystal is not applied. By utilizing this, there is an effect that the direction of spontaneous polarization of the ferroelectric liquid crystal can be controlled.

  In order to investigate the direction of spontaneous polarization of the ferroelectric liquid crystal, the inventors conducted the following experiment.

First, a liquid crystal display element in which a ferroelectric liquid crystal was sandwiched between a pair of alignment films was manufactured by a liquid crystal dropping method.
A 2% by mass cyclopentanone solution of photo-dimerization reaction type orientation material (Rolic technologies, trade name: ROP103) is applied to two glass substrates on which ITO electrodes are formed for 15 seconds at a rotation speed of 1500 rpm. After spin coating and drying on a hot plate at 130 ° C. for 15 minutes, alignment treatment was performed by irradiation with polarized ultraviolet rays at 25 ° C. at 100 mJ / cm ² .

  Next, a ferroelectric liquid crystal (manufactured by AZ Electronic Materials, trade name: R2301) is applied in an isotropic phase on one substrate (in this experiment, a liquid crystal side substrate) by an inkjet method. did. Next, an ultraviolet heat curable sealant (manufactured by Kyoritsu Kagaku Sangyo Co., Ltd., trade name: WORLD ROCK 718) was applied to the peripheral edge of the liquid crystal side substrate using a seal dispenser.

Next, the hot plate disposed in the vacuum chamber was heated to 110 ° C., and the liquid crystal side substrate coated with the ferroelectric liquid crystal was placed on the hot plate. Next, the other substrate (referred to as a counter substrate in this experiment) is adsorbed by an adsorption plate heated to 110 ° C. so that the alignment processing directions of the alignment films of the liquid crystal side substrate and the counter substrate are parallel to each other. Opposed. Subsequently, both substrates were brought into close contact with each other in a state where the vacuum chamber was evacuated so that the pressure between the substrates was sufficiently reduced, and then the inside of the vacuum chamber was returned to normal pressure. Next, ultraviolet rays were irradiated at 1 J / cm ² to cure the ultraviolet curable sealant, and both substrates were adhered. Next, the liquid crystal cell was gradually cooled to room temperature to align the ferroelectric liquid crystal, thereby producing a liquid crystal display element.

  When a voltage was applied so that the electrode of the liquid crystal side substrate was a negative electrode, the molecular direction of the ferroelectric liquid crystal changed about twice the tilt angle. About 75% of the ferroelectric liquid crystal molecules were changed in molecular direction by about twice the tilt angle.

  Further, when the liquid crystal display element in which the ferroelectric liquid crystal is sandwiched between the pair of alignment films by the liquid crystal dropping method as described above by changing the kinds and combinations of the alignment materials, the same result as above is obtained. Obtained.

Next, a liquid crystal display element in which a ferroelectric liquid crystal was sandwiched between a pair of alignment films was fabricated by a vacuum injection method.
A 2% by mass cyclopentanone solution of photo-dimerization reaction type orientation material (Rolic technologies, trade name: ROP103) is applied to two glass substrates on which ITO electrodes are formed for 15 seconds at a rotation speed of 1500 rpm. After spin coating and drying on a hot plate at 130 ° C. for 15 minutes, alignment treatment was performed by irradiation with polarized ultraviolet rays at 25 ° C. at 100 mJ / cm ² .

Next, an ultraviolet heat curable sealant (manufactured by Kyoritsu Chemical Industry Co., Ltd., trade name: WARLD ROCK 718) was applied to the peripheral edge of one substrate using a seal dispenser. Next, the two substrates were opposed to each other so that the alignment treatment directions of the respective alignment films were parallel, and thermocompression bonding was performed to obtain an empty liquid crystal cell.
Next, a ferroelectric liquid crystal (manufactured by AZ Electronic Materials, trade name: R2301) was injected into the empty liquid crystal cell in an isotropic phase state. Next, the liquid crystal cell was gradually cooled to room temperature to align the ferroelectric liquid crystal, thereby producing a liquid crystal display element.

  When a voltage is applied so that the electrode of one substrate is a negative electrode, the molecular direction of some ferroelectric liquid crystals changes about twice the tilt angle, but the molecular direction of some ferroelectric liquid crystals changes. There wasn't. About 50% of the ferroelectric liquid crystal molecules were changed in molecular direction by about twice the tilt angle.

  In addition, by changing the types and combinations of the alignment materials, a liquid crystal display element in which a ferroelectric liquid crystal was sandwiched between a pair of alignment films by a vacuum injection method as described above was produced. Various results such as a direction whose direction changed about twice the tilt angle was about 50% of the whole, about 70% or more of the whole, and less than about 30% of the whole. Obtained.

  From the results of the above experiment, when the present inventors produce a liquid crystal display element by the liquid crystal dropping method, the spontaneous polarization of the ferroelectric liquid crystal tends to be directed toward the substrate side on which the ferroelectric liquid crystal is not applied. I got the knowledge.

  Hereinafter, the manufacturing method of the liquid crystal display element and the liquid crystal display element of the present invention will be described in detail.

A. Manufacturing method of liquid crystal display element The manufacturing method of the liquid crystal display element of the present invention is the above-mentioned first alignment film of the liquid crystal side substrate in which the first electrode layer and the first alignment film are laminated in this order on the first substrate. A liquid crystal coating process for coating ferroelectric liquid crystal, a liquid crystal side substrate coated with the ferroelectric liquid crystal, and a substrate bonding process for bonding a counter substrate having a second electrode layer formed on a second substrate. And the ferroelectric liquid crystal exhibits monostability, and when a voltage is applied so that the first electrode layer is a negative electrode, the molecular direction of the ferroelectric liquid crystal is the liquid crystal side. It is characterized in that it changes approximately twice the tilt angle of the ferroelectric liquid crystal in parallel with the substrate surface.

The manufacturing method of the liquid crystal display element of this invention is demonstrated referring drawings. FIG. 1 is a process diagram showing an example of a method for producing a liquid crystal display element of the present invention.
First, the liquid crystal side substrate 1 is prepared by forming the first alignment film 4 on the first base material 2 on which the first electrode layer 3 is formed (FIG. 1A).

  Next, the ferroelectric liquid crystal 5 is heated to a temperature at which the ferroelectric liquid crystal exhibits an isotropic phase (for example, 100 ° C.), and the ferroelectric liquid crystal 5 is formed on the first alignment film 4 by using an inkjet device. Application is performed in the state of a phase (FIG. 1B, liquid crystal application step). At this time, as illustrated in FIG. 2, the ferroelectric liquid crystal 5 is applied in the form of continuous dots and stripes. At this time, the ferroelectric liquid crystal 5 is heated to a temperature exhibiting an isotropic phase (for example, 100 ° C.), but the liquid crystal side substrate is set to room temperature, so that the liquid crystal side is higher than the temperature of the ferroelectric liquid crystal. The temperature of the substrate is lower. Therefore, the ferroelectric liquid crystal applied on the liquid crystal side substrate is cooled. In general, the viscosity of liquid crystals increases as the temperature decreases. Therefore, the ferroelectric liquid crystal applied on the liquid crystal side substrate is cooled to increase the viscosity and stop flowing.

  Next, a sealing agent 6 is applied on the first alignment film 4 (FIG. 1C). At this time, as illustrated in FIG. 2, the sealant 6 is applied to the peripheral portion of the first base material 2 so as to surround the outer periphery of the region where the ferroelectric liquid crystal 5 is applied. In FIG. 2, the first electrode layer and the first alignment film are omitted.

Next, as shown in FIG. 1D, the second alignment film 14 is formed on the second base material 12 on which the second electrode layer 13 is formed, and the counter substrate 11 is prepared. Next, the liquid crystal side substrate 1 coated with the ferroelectric liquid crystal 5 is heated to a temperature at which the ferroelectric liquid crystal exhibits an isotropic phase (for example, 100 ° C.). As a result, the ferroelectric liquid crystal 5 applied on the liquid crystal side substrate 1 is heated to be in an isotropic phase, and the viscosity is lowered to flow on the first alignment film 4. Subsequently, the liquid crystal side substrate 1 coated with the ferroelectric liquid crystal 5 and the counter substrate 11 are opposed so that the alignment treatment directions of the first alignment film 4 and the second alignment film 14 are substantially parallel.
Next, as shown in FIG. 1 (e), the liquid crystal side substrate 1 and the counter substrate 11 are sufficiently depressurized, the liquid crystal side substrate 1 and the counter substrate 11 are overlaid under a reduced pressure, and a predetermined pressure 21 is applied. Make the cell gap uniform. Subsequently, pressure is further applied between the liquid crystal side substrate 1 and the counter substrate 11 by returning to normal pressure. Next, the region 22 to which the sealant 6 is applied is irradiated with ultraviolet rays 22 to cure the sealant 6, and the liquid crystal side substrate 1 and the counter substrate 11 are bonded (substrate bonding step).

  Thereafter, although not shown, the sealed ferroelectric liquid crystal is aligned by slowly cooling to room temperature.

  The ferroelectric liquid crystal used in the present invention exhibits monostability, and when a voltage is applied so that the first electrode layer is a negative electrode, the molecular direction of the ferroelectric liquid crystal is on the liquid crystal side substrate surface. On the other hand, it changes approximately twice the tilt angle of the ferroelectric liquid crystal in parallel.

  In the ferroelectric liquid crystal, as illustrated in FIG. 3, the liquid crystal molecules 15 are tilted from the layer normal z, and rotate along a cone ridge having a bottom surface perpendicular to the layer normal z. In such a cone, the tilt angle of the liquid crystal molecules 15 with respect to the layer normal z is referred to as a tilt angle θ.

  “Showing monostability” means a state in which the state of the ferroelectric liquid crystal when no voltage is applied is stabilized in one state. More specifically, as shown in FIG. 3, the liquid crystal molecules 15 can operate on a cone between two states inclined by a tilt angle ± θ with respect to the layer normal z. 15 is the state stabilized in any one state on the cone.

  From the above experimental results, after applying the ferroelectric liquid crystal on the liquid crystal side substrate, and then bonding the liquid crystal side substrate and the counter substrate to produce a liquid crystal display element, on the counter substrate side where the ferroelectric liquid crystal was not applied. It was found that the spontaneous polarization of the ferroelectric liquid crystal tends to be suitable. This is considered to be due to the influence of the polar surface interaction, which is the interaction between the ferroelectric liquid crystal and the first alignment film surface coated with the ferroelectric liquid crystal. For example, as shown in FIG. 1B, after applying the ferroelectric liquid crystal 5 on the first alignment film 4 of the liquid crystal side substrate 1, the liquid crystal side substrate 1 is brought to a temperature at which the ferroelectric liquid crystal exhibits an isotropic phase. When heated, the ferroelectric liquid crystal 5 enters an isotropic phase and flows on the first alignment film 4 as shown in FIG. At this time, the ferroelectric liquid crystal 5 that flows in an isotropic phase on the first alignment film 4 is in contact with the first alignment film 4 and air (not shown). It is considered that the first alignment film has a stronger positive polarity in the first alignment film and air. Therefore, as illustrated in FIG. 4, it is considered that the spontaneous polarization Ps of the liquid crystal molecules 15 faces the opposite side of the first alignment film 4 by the polar surface interaction. In FIG. 4, the first base material and the first electrode layer are omitted, and the liquid crystal molecules are shown for the ferroelectric liquid crystal.

  When the liquid crystal side substrate and the counter substrate are bonded, for example, the liquid crystal side substrate and the counter substrate are heated to a temperature at which the ferroelectric liquid crystal exhibits an isotropic phase (for example, 100 ° C.). After bonding, the ferroelectric liquid crystal is cooled to room temperature and aligned. At this time, there is a concern that the polar surface interaction between the ferroelectric liquid crystal and the second alignment film of the counter substrate may also affect the direction of spontaneous polarization of the ferroelectric liquid crystal. However, after the ferroelectric liquid crystal flows over the first alignment film in an isotropic phase and the spontaneous polarization of the ferroelectric liquid crystal faces the opposite side of the first alignment film, the liquid crystal side substrate and the counter substrate It is considered that the ferroelectric liquid crystal is not affected so as to reverse the direction of the spontaneous polarization during the bonding of the liquid crystal and the alignment of the ferroelectric liquid crystal. Therefore, it is considered that the direction of spontaneous polarization is maintained even after the substrate bonding step.

  From the above, in the liquid crystal display element obtained by the present invention, when no voltage is applied, the spontaneous polarization Ps of the liquid crystal molecules 15 is opposite to the first alignment film 4, that is, the second alignment, as illustrated in FIG. It is thought that it faces the film 14 side. In FIG. 5, the first base material and the second base material are omitted.

  Further, in the liquid crystal display element obtained by the present invention, as illustrated in FIG. 6, when a voltage is applied so that the first electrode layer 3 is a negative electrode (−) and the second electrode layer 13 is a positive electrode (+), Due to the influence of the polarity of the applied voltage, the spontaneous polarization Ps of the liquid crystal molecules 15 comes to face the first alignment film 4 side. In FIG. 6, the first base material and the second base material are omitted.

  Further, when a voltage is applied such that the first electrode layer is a positive electrode (+) and the second electrode layer is a negative electrode (−), the liquid crystal molecules 15 are affected by the polarity of the applied voltage, as illustrated in FIG. Spontaneous polarization Ps comes to face the second alignment film 14 side. In this case, the direction of spontaneous polarization is the same as that in the state where no voltage is applied.

  When a voltage is not applied or a voltage having a positive polarity applied to the first electrode layer (FIG. 5) is changed to a voltage having a negative polarity applied to the first electrode layer (FIG. 6), the negative voltage of the applied voltage is applied. 7 and the negative polarity of the spontaneous polarization of the liquid crystal molecules, the liquid crystal molecules 15 rotate about an angle of about 2θ as illustrated in FIG. That is, when a voltage is applied so that the first electrode layer is a negative electrode, the molecular direction of the ferroelectric liquid crystal is parallel to the liquid crystal side substrate surface and is approximately twice the tilt angle θ of the ferroelectric liquid crystal. It will change.

  As described above, the present invention utilizes the fact that the spontaneous polarization of the ferroelectric liquid crystal tends to be directed to the opposite side of the first alignment film, that is, the counter substrate side on which the ferroelectric liquid crystal is not applied. It is possible to control the direction of spontaneous polarization of the molecule.

In general, in a liquid crystal display element using ferroelectric liquid crystal, two opposing alignment films are arranged so that their alignment treatment directions are parallel to each other. For example, in the liquid crystal display element shown in FIG. 5, when no voltage is applied, the liquid crystal molecules 15 are aligned along the alignment treatment direction d of the first alignment film and the second alignment film as illustrated in FIG. A uniform orientation state is obtained. When a voltage is applied so that the first electrode layer is a negative electrode (−) and the second electrode layer is a positive electrode (+), the spontaneous polarization Ps is caused by the influence of the polarity of the applied voltage as illustrated in FIG. 8B. The direction of is reversed. Also in this case, the liquid crystal molecules 15 are in a uniform alignment state. Furthermore, when a voltage is applied so that the first electrode layer is a positive electrode (+) and the second electrode layer is a negative electrode (−), the spontaneous polarization Ps is caused by the influence of the polarity of the applied voltage as illustrated in FIG. The direction of is reversed. In this case, the liquid crystal molecules 15 are in an alignment state similar to that in the state where no voltage is applied.
FIG. 8A is a schematic diagram showing the alignment state of the liquid crystal molecules from the upper surface of FIG. 5, and the spontaneous polarization Ps is directed from the back of the page to the near side (the mark ● in FIG. 8A). ). FIG. 8B is a schematic diagram showing the alignment state of the liquid crystal molecules from the upper surface of FIG. 6, and the spontaneous polarization Ps is directed from the front side to the back side of the drawing (the mark “X” in FIG. 8B). ).

  In the present invention, since the direction of spontaneous polarization can be controlled as described above, the alignment of the ferroelectric liquid crystal can be mono-stabilized without causing alignment defects. That is, the ferroelectric liquid crystal exhibits monostability. In addition, since the ferroelectric liquid crystal is aligned without using the method of slow cooling by applying an electric field, there is an advantage that the alignment can be maintained even when the temperature is raised above the phase transition temperature and the occurrence of alignment defects can be suppressed.

  In the above description, the second alignment film is formed on the counter substrate as an example. However, the present invention is not limited to this, and the second alignment film is not formed on the counter substrate. Also good. Even when the counter substrate has the second electrode layer formed on the second substrate and does not have the second alignment film, the ferroelectric liquid crystal is applied on the first alignment film of the liquid crystal side substrate. When the ferroelectric liquid crystal is in an isotropic phase and flows on the first alignment film, the spontaneous polarization of the ferroelectric liquid crystal faces the opposite side of the first alignment film due to the polar surface interaction. Therefore, the direction of spontaneous polarization of the ferroelectric liquid crystal can be controlled, and the alignment of the ferroelectric liquid crystal can be mono-stabilized without causing alignment defects.

  When a voltage is applied so that the first electrode layer is a negative electrode, it is preferable that there are 80% or more, in which the molecular direction of the ferroelectric liquid crystal changes about twice the tilt angle, more preferably 90% or more, More preferably, it is 95% or more. This is because a favorable contrast ratio can be obtained within the above range.

In addition, said ratio can be measured as follows.
For example, as shown in FIG. 9, the liquid crystal side substrate 1 in which the first electrode layer 3 and the first alignment film 4 are laminated on the first substrate 2, and the second electrode layer 13 and the first substrate 12 on the second substrate 12. In the liquid crystal display element in which the ferroelectric liquid crystal 5 is sandwiched between the counter substrate 11 on which the two alignment films 14 are laminated, polarizing plates 17a and 17b are provided outside the liquid crystal side substrate 1 and the counter substrate 11, respectively. It is assumed that light is incident from the polarizing plate 17a side and light is emitted from the polarizing plate 17b side. The two polarizing plates 17a and 17b have their polarization axes substantially perpendicular to each other, and the polarization axis of the polarizing plate 17a and the alignment treatment direction (the alignment direction of the liquid crystal molecules) of the first alignment film 4 are substantially parallel. Are arranged as follows.

  When no voltage is applied, the linearly polarized light transmitted through the polarizing plate 17a and the alignment direction of the liquid crystal molecules coincide with each other. Therefore, the refractive index anisotropy of the liquid crystal molecules does not appear, and the linearly polarized light transmitted through the polarizing plate 17a remains as it is. It passes through the molecules, is blocked by the polarizing plate 17b, and enters a dark state. On the other hand, in the voltage application state, the liquid crystal molecules move on the cone, and the linearly polarized light transmitted through the polarizing plate 17a and the alignment direction of the liquid crystal molecules have a predetermined angle. Therefore, the linearly polarized light transmitted through the polarizing plate 17a. Becomes elliptically polarized light due to the birefringence of the liquid crystal molecules. Of the elliptically polarized light, only linearly polarized light that coincides with the polarization axis of the polarizing plate 17b is transmitted through the polarizing plate 17b and becomes bright.

  Therefore, when a voltage is applied so that the first electrode layer is a negative electrode, a bright state is obtained when the molecular direction of the ferroelectric liquid crystal changes approximately twice the tilt angle. On the other hand, when a voltage is applied so that the first electrode layer is a negative electrode, for example, when a portion of the ferroelectric liquid crystal whose molecular direction does not change partially exists, a dark state is partially obtained. Therefore, from the white / black area ratio of black and white (bright / dark) display obtained when the voltage is applied, the molecular direction of the ferroelectric liquid crystal is about 2 of the tilt angle when the voltage is applied so that the first electrode layer is a negative electrode. The ratio of what doubles can be calculated.

Further, in the liquid crystal display element provided with the polarizing plate as described above, the dark state is positive when the voltage is not applied and the negative polarity voltage is applied to the second electrode layer. The light state is obtained when the polarity voltage is applied. Therefore, when the liquid crystal display element is driven by the field sequential color system, as illustrated in FIG. 10, for example, when the G (green) backlight is turned on, the liquid crystal display element is brightened by scanning synchronized with the R (red) backlight. It is possible to avoid the state.
Note that the symbols and the like in FIG. 10 are the same as the symbols and the like shown in FIG.

The method for producing a liquid crystal display element of the present invention may have a liquid crystal coating process and a substrate bonding process, but before the liquid crystal coating process, the first electrode layer and the first alignment film on the first substrate. A liquid crystal side substrate preparing step for preparing a liquid crystal side substrate laminated in this order, and a counter substrate preparing step for preparing a counter substrate in which the second electrode layer is formed on the second base material may be performed.
Hereafter, each process in the manufacturing method of the ferroelectric liquid crystal used for this invention and the liquid crystal display element of this invention is demonstrated.

1. Ferroelectric liquid crystal The ferroelectric liquid crystal used in the present invention is monostable, and when a voltage is applied so that the first electrode layer is a negative electrode, the molecular direction of the ferroelectric liquid crystal is the liquid crystal side. It changes approximately twice the tilt angle of the ferroelectric liquid crystal in parallel with the substrate surface.

  "When a voltage is applied so that the first electrode layer is a negative electrode, the molecular direction of the ferroelectric liquid crystal changes about twice the tilt angle θ of the ferroelectric liquid crystal with respect to the liquid crystal side substrate surface." Means that when no voltage is applied, the liquid crystal molecules are stabilized in one state on the cone, and when the voltage is applied so that the first electrode layer is a negative electrode, the liquid crystal molecules are moved from the mono-stabilized state on the cone. When a voltage is applied so that the first electrode layer is positive, the liquid crystal molecules maintain a mono-stabilized state or the first electrode layer becomes a negative electrode from the mono-stabilized state. Thus, the inclination angle from the mono-stabilized state of the liquid crystal molecules when the voltage is applied so that the first electrode layer is negative, and the first electrode layer is positive is positive. Than the tilt angle from the mono-stabilized state of the liquid crystal molecules when a voltage is applied so that It refers to hear.

  FIG. 11 is a schematic diagram illustrating an example of the alignment state of a ferroelectric liquid crystal exhibiting monostability. 11A shows a case where no voltage is applied, FIG. 11B shows a case where a voltage is applied so that the first electrode layer becomes a negative electrode, and FIG. 11C shows a case where the first electrode layer becomes a positive electrode. A case where a voltage is applied is shown. When no voltage is applied, the liquid crystal molecules 15 are stabilized in one state on the cone (FIG. 11A). When a voltage is applied so that the first electrode layer is a negative electrode, the liquid crystal molecules 15 are tilted from the stabilized state (broken line) to one side (FIG. 11B). In addition, when a voltage is applied so that the first electrode layer becomes a positive electrode, the liquid crystal molecules 15 are in a state where a voltage is applied so that the first electrode layer becomes a negative electrode from a stabilized state (broken line). It tilts to the opposite side (FIG. 11 (c)). At this time, the inclination angle δ when the voltage is applied so that the first electrode layer becomes the negative electrode is larger than the inclination angle ω when the voltage is applied so that the first electrode layer becomes the positive electrode. In addition, in FIG. 11, d shows an orientation process direction and z shows a layer normal line.

  When a voltage is applied so that the first electrode layer is a negative electrode, the liquid crystal molecules are inclined from the mono-stabilized state to one side on the cone at an angle corresponding to the magnitude of the applied voltage. Further, in the ferroelectric liquid crystal, as illustrated in FIG. 11A, the position A (the direction of the liquid crystal molecules 15), the position B (the alignment treatment direction d), and the position C do not necessarily match. Absent. Therefore, as illustrated in FIG. 11B, the maximum tilt angle δ when a voltage is applied so that the first electrode layer is a negative electrode is approximately twice the tilt angle θ (angle 2θ).

  For example, as shown in FIG. 7, the direction of the liquid crystal molecules 15 changes approximately twice the tilt angle θ (angle 2θ) in parallel to the liquid crystal side substrate surface. Double change refers to the case of 2θ-2θ-5 ° change.

  The angle at which the molecular direction of the ferroelectric liquid crystal changes in parallel to the liquid crystal side substrate surface can be measured as follows. First, a polarizing microscope and a liquid crystal display element in which polarizing plates are arranged in crossed Nicols are arranged so that the polarization axis of one polarizing plate and the alignment direction of liquid crystal molecules in the liquid crystal layer are parallel, and this position is used as a reference. . When a voltage is applied, the liquid crystal molecules come to have a predetermined angle with the polarization axis, so that the polarized light transmitted through one polarizing plate is transmitted through the other polarizing plate to be in a bright state. With this voltage applied, the liquid crystal display element is rotated to a dark state. And the angle which rotated the liquid crystal display element at this time is measured. The angle at which the liquid crystal display element is rotated is the angle at which the molecular direction of the ferroelectric liquid crystal changes in parallel to the liquid crystal side substrate surface.

  As described above, when a voltage is applied so that the first electrode layer is a negative electrode, the liquid crystal molecules are inclined from the mono-stabilized state to one side on the cone at an angle according to the magnitude of the applied voltage. When the liquid crystal display element is actually driven, the direction of the liquid crystal molecules does not change about twice the tilt angle when a voltage is applied so that the first electrode layer is a negative electrode.

Specifically, as such a ferroelectric liquid crystal, for example, half-V shaped switching (hereinafter referred to as HV-shaped switching) in which liquid crystal molecules operate only when a positive or negative voltage as shown in FIG. 12 is applied. A ferroelectric liquid crystal exhibiting characteristics is used. When the ferroelectric liquid crystal exhibiting such HV-shaped switching characteristics is used, the opening time as a black and white shutter can be made sufficiently long, whereby each color that can be temporally switched can be displayed brighter. A bright color liquid crystal display element can be realized.
The “HV-shaped switching characteristic” refers to an electro-optical characteristic in which the light transmittance with respect to an applied voltage is asymmetric.

The phase series of the ferroelectric liquid crystal is not particularly limited as long as it exhibits a chiral smectic C phase (SmC ^* ). For example, the phase sequence changes in phase with the nematic phase (N) -cholesteric phase (Ch) -chiral smectic C phase (SmC ^* ) in the temperature lowering process, the nematic phase (N) -chiral smectic C phase (SmC ^* ) , Nematic phase (N) -smectic A phase (SmA) -chiral smectic C phase (SmC ^* ), phase change, nematic phase (N) -cholesteric phase (Ch) -smectic A phase (SmA ) -Chiral smectic C phase (SmC ^* ) and the like.

  In general, a ferroelectric liquid crystal having a phase sequence passing through an SmA phase as illustrated in the lower part of FIG. 13 has a small distance between smectic layers in the process of phase change, and a smectic layer is used to compensate for the volume change. A domain having a bent chevron structure and different major axis directions of the liquid crystal molecules is formed depending on the bending direction, and alignment defects called zigzag defects and hairpin defects are likely to occur at the interface. In general, a ferroelectric liquid crystal having a phase sequence that does not pass through the SmA phase as illustrated in the upper part of FIG. 13 is likely to generate two regions (double domains) having different layer normal directions. In the present invention, the alignment of the ferroelectric liquid crystal can be mono-stabilized without causing such alignment defects.

  Such a ferroelectric liquid crystal can be variously selected from generally known liquid crystal materials according to required characteristics.

In particular, a liquid crystal material that exhibits an SmC ^* phase from the Ch phase without passing through the SmA phase is suitable as a material that exhibits HV-shaped switching characteristics. Specifically, “R2301” manufactured by AZ Electronic Materials may be mentioned.

In addition, as the liquid crystal material that passes through the SmA phase, a material that expresses the SmC ^* phase from the Ch phase through the SmA phase is preferable because of a wide range of material selection. In this case, a single liquid crystal material exhibiting an SmC ^* phase can be used, but a non-chiral liquid crystal (hereinafter sometimes referred to as a host liquid crystal) having a low viscosity and easily exhibiting an SmC phase is used. By adding a small amount of an optically active substance that does not show large spontaneous polarization and an appropriate helical pitch, the liquid crystal material showing the phase sequence as described above has low viscosity and can realize faster response. preferable.

The host liquid crystal is preferably a material exhibiting an SmC phase in a wide temperature range, and can be used without particular limitation as long as it is generally known as a host liquid crystal of a ferroelectric liquid crystal. For example, the general formula:
^{Ra-Q 1 -X 1 - (} Q 2 -Y 1) m -Q 3 -Rb
(In the formula, Ra and Rb are each a linear or branched alkyl group, alkoxy group, alkoxycarbonyl group, alkanoyloxy group or alkoxycarbonyloxy group, and Q ¹ , Q ² and Q ³ are each 1 , 4-phenylene group, 1,4-cyclohexylene group, pyridine-2,5-diyl group, pyrazine-2,5-diyl group, pyridazine-3,6-diyl group, 1,3-dioxane-2,5 -Diyl group, and these groups may have a substituent such as a halogen atom, a hydroxyl group, and a cyano group, and X ¹ and Y ¹ are each —COO—, —OCO—, —CH ₂ O— , —OCH ₂ —, —CH ₂ CH ₂ —, —C≡C—, or a single bond, and m is 0 or 1.). As the host liquid crystal, the above compounds can be used alone or in combination of two or more.

The optically active substance added to the host liquid crystal is not particularly limited as long as it is a material having a large spontaneous polarization and the ability to induce an appropriate helical pitch, and is generally added to a liquid crystal composition exhibiting an SmC phase. Any known material can be used. In particular, a material that can induce large spontaneous polarization with a small addition amount is preferable. Examples of such an optically active substance include the following general formula:
^{Rc-Q 1 -Za-Q 2} -Zb-Q 3 -Zc-Rd
(In the formula, Q ¹ , Q ² and Q ³ represent the same meaning as in the above general formula, and Za, Zb and Zc are —COO—, —OCO—, —CH ₂ O—, —OCH ₂ —, —CH _{2, respectively.} CH ₂ —, —C≡C—, —CH═N—, —N═N—, —N (→ O) ═N—, —C (═O) S— or a single bond, and Rc is asymmetric. A linear or branched alkyl group which may have a carbon atom, an alkoxy group, an alkoxycarbonyl group, an alkanoyloxy group or an alkoxycarbonyloxy group, wherein Rd is a linear or branched group having an asymmetric carbon atom; And an alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkanoyloxy group or an alkoxycarbonyloxy group, and Rc and Rd may be substituted with a halogen atom, a cyano group or a hydroxyl group. Can be used. As the optically active substance, the above compounds may be used alone or in combination of two or more.

  Specific examples of the ferroelectric liquid crystal passing through the SmA phase include “FELIXM4851-100” manufactured by AZ Electronic Materials.

In a liquid crystal display element using a ferroelectric liquid crystal exhibiting monostability, the transmittance depends on the tilt angle of liquid crystal molecules when a voltage is applied. When either positive or negative voltage is applied, the liquid crystal molecules are tilted on the cone. Therefore, for example, as shown in FIG. 12, the tilt angle of the liquid crystal molecules changes according to the magnitude of the applied voltage, and the transmittance changes. At this time, the transmittance is maximized when the tilt angle of the liquid crystal molecules from the monostable state is 45 °.
Therefore, in order to realize high transmittance, when a voltage is applied so that the first electrode layer becomes a negative electrode during actual driving, the inclination angle of the liquid crystal molecules from a monostable state can be 45 °. It is preferable to use a dielectric liquid crystal.
For example, when a ferroelectric liquid crystal having a maximum tilt angle δ from a monostable state of liquid crystal molecules as shown in FIG. 11 is larger than 45 °, when the liquid crystal display element is actually driven, When a voltage is applied so that the first electrode layer is a negative electrode, the inclination angle of the liquid crystal molecules from the monostable state can be set to 45 °. As described above, when a voltage is applied so that the first electrode layer becomes a negative electrode during actual driving, the direction of the liquid crystal molecules does not change approximately twice the tilt angle.

  A compound having an arbitrary function can be added to the ferroelectric liquid crystal depending on the function required for the liquid crystal display element. Examples of this compound include polymerizable monomers. By adding a polymerizable monomer to the ferroelectric liquid crystal and polymerizing the polymerizable monomer after the substrate bonding step, the alignment of the ferroelectric liquid crystal is so-called “polymer stabilization”, and excellent alignment stability is achieved. It is because it is obtained.

  The polymerizable monomer is not particularly limited as long as it is a compound that generates a polymer by a polymerization reaction, and is a thermosetting resin monomer that generates a polymerization reaction by heat treatment, and active radiation that generates a polymerization reaction by irradiation with actinic radiation. A curable resin monomer can be mentioned. Among these, it is preferable to use an actinic radiation curable resin monomer. When a thermosetting resin monomer is used, it is necessary to perform a heating process in order to cause a polymerization reaction. Therefore, the regular arrangement of the ferroelectric liquid crystal is impaired by such a heating process, There is a risk of inducing a phase transition. On the other hand, when the actinic radiation curable resin monomer is used, there is no such fear, and the alignment of the ferroelectric liquid crystal is hardly harmed by the polymerization reaction.

  Examples of the actinic radiation curable resin monomer include an electron beam curable resin monomer that undergoes a polymerization reaction upon irradiation with an electron beam, and a photocurable resin monomer that undergoes a polymerization reaction upon irradiation with light. Among these, it is preferable to use a photocurable resin monomer. It is because a manufacturing process can be simplified by using a photocurable resin monomer.

  The photocurable resin monomer is not particularly limited as long as it causes a polymerization reaction when irradiated with light having a wavelength in the range of 150 nm to 500 nm. Among them, it is preferable to use an ultraviolet curable resin monomer that generates a polymerization reaction when irradiated with light having a wavelength in the range of 250 nm to 450 nm, particularly in the range of 300 nm to 400 nm. This is because it has advantages in terms of the ease of the irradiation apparatus.

  The polymerizable functional group possessed by the ultraviolet curable resin monomer is not particularly limited as long as it causes a polymerization reaction upon irradiation with ultraviolet rays in the above wavelength region. In particular, it is preferable to use an ultraviolet curable resin monomer having an acrylate group.

  Further, the UV curable resin monomer may be a monofunctional monomer having one polymerizable functional group in one molecule, or a polyfunctional having two or more polymerizable functional groups in one molecule. It may be a monomer. Among these, it is preferable to use a polyfunctional monomer. By using a polyfunctional monomer, a stronger polymer network can be formed, so that the intermolecular force and the polymer network at the alignment film interface can be strengthened. Thereby, the disorder of the alignment of the ferroelectric liquid crystal due to the temperature change can be suppressed.

  Among the polyfunctional monomers, bifunctional monomers having a polymerizable functional group at both ends of the molecule are preferably used. By having a polymerizable functional group at both ends of the molecule, it is possible to form a polymer network with a wide interval between polymers, and to prevent a decrease in driving voltage of the ferroelectric liquid crystal due to the inclusion of a polymer of a polymerizable monomer. Because.

  Of the ultraviolet curable resin monomers, it is preferable to use an ultraviolet curable liquid crystal monomer that exhibits liquid crystallinity. The reason why such an ultraviolet curable liquid crystal monomer is preferable is as follows. That is, since the ultraviolet curable liquid crystal monomer exhibits liquid crystallinity, it can be regularly arranged by the alignment regulating force of the alignment film. For this reason, the ultraviolet curable liquid crystal monomer can be fixed while maintaining the regular alignment state by causing a polymerization reaction after the ultraviolet light curable liquid crystal monomer is regularly arranged. By the presence of the polymer having such a regular alignment state, the alignment stability of the ferroelectric liquid crystal can be improved, and excellent heat resistance and impact resistance can be obtained.

  The liquid crystal phase exhibited by the ultraviolet curable liquid crystal monomer is not particularly limited, and examples thereof include an N phase, an SmA phase, and an SmC phase.

  Examples of the ultraviolet curable liquid crystal monomer used in the present invention include compounds represented by the following formulas (1) to (3).

In the above formulas (1) and (2), A, B, D, E and F represent benzene, cyclohexane or pyrimidine, and these may have a substituent such as halogen. A and B, or D and E may be bonded via a bonding group such as an acetylene group, a methylene group, or an ester group. M ¹ and M ² may be any of a hydrogen atom, an alkyl group having 3 to 9 carbon atoms, an alkoxycarbonyl group having 3 to 9 carbon atoms, or a cyano group. Further, the acryloyloxy group at the end of the molecular chain and A or D may be bonded via a bonding group such as an alkylene group having 3 to 6 carbon atoms.

  In the above formula (3), Y is hydrogen, alkyl having 1 to 20 carbons, alkenyl having 1 to 20 carbons, alkyloxy having 1 to 20 carbons, alkyloxycarbonyl having 1 to 20 carbons, It represents formyl, alkylcarbonyl having 1 to 20 carbons, alkylcarbonyloxy having 1 to 20 carbons, halogen, cyano or nitro.

  Among the above, the compounds represented by the following formulas can be exemplified as those suitably used.

  Moreover, the said polymerizable monomer may be used independently and may be used in combination of 2 or more type. When two or more different polymerizable monomers are used, for example, an ultraviolet curable liquid crystal monomer represented by the above formula and another ultraviolet curable resin monomer can be used.

  When an ultraviolet curable liquid crystal monomer is used as the polymerizable monomer, the polymer obtained by polymerizing the polymerizable monomer includes a main chain that exhibits liquid crystallinity by having an atomic group exhibiting liquid crystallinity in the main chain. It may be a chain liquid crystal polymer, or may be a side chain liquid crystal polymer in which the side chain exhibits liquid crystallinity by having an atomic group exhibiting liquid crystallinity in the side chain. Especially, it is preferable that the polymer of a polymerizable monomer is a side chain liquid crystal type polymer. This is because the presence of an atomic group exhibiting liquid crystallinity in the side chain increases the degree of freedom of the atomic group, so that the atomic group exhibiting liquid crystallinity is easily aligned. Further, as a result, the alignment stability of the ferroelectric liquid crystal can be improved.

  The addition amount of the polymerizable monomer is not particularly limited as long as the alignment stability of the ferroelectric liquid crystal is within a desired range, but is not limited to the total mass of the ferroelectric liquid crystal and the polymerizable monomer. In the range of 0.5% by mass to 30% by mass, more preferably in the range of 1% by mass to 20% by mass, and still more preferably in the range of 1% by mass to 10% by mass. This is because if the addition amount of the polymerizable monomer is larger than the above range, the driving voltage of the ferroelectric liquid crystal may increase or the response speed may decrease. Further, when the addition amount of the polymerizable monomer is less than the above range, the alignment stability of the ferroelectric liquid crystal becomes insufficient, and the heat resistance and impact resistance may be lowered.

  In the present invention, since the ferroelectric liquid crystal exhibits monostability, a liquid crystal display element that can be driven by an active matrix method using a thin film transistor (TFT) and can control gradation by voltage modulation is provided. Can be obtained.

2. Liquid Crystal Side Substrate Preparation Step In the present invention, a liquid crystal side substrate preparation step of preparing a liquid crystal side substrate in which the first electrode layer and the first alignment film are laminated in this order on the first base material may be performed. The liquid crystal side substrate preparation step may include a first alignment film forming step for forming the first alignment film on the first base material on which the first electrode layer is formed, and further on the first alignment film. It is preferable to have a reactive liquid crystal layer forming step of forming a reactive liquid crystal layer formed by fixing the reactive liquid crystal. Moreover, it is also preferable to have the partition formation process which forms a partition on the 1st base material. In this case, the first alignment film forming step is performed after the partition wall forming step.
Hereinafter, each process in the liquid crystal side substrate preparation process will be described.

(1) First alignment film forming step The first alignment film forming step in the present invention is a step of forming the first alignment film on the first substrate on which the first electrode layer is formed.

  The method for forming the first alignment film is not particularly limited as long as the first alignment film capable of aligning the ferroelectric liquid crystal is obtained. For example, a first alignment film can be formed by forming a film on the first electrode layer and subjecting this film to rubbing treatment, photo-alignment treatment, or the like.

  When the first alignment film is subjected to photo-alignment treatment, the direction of spontaneous polarization of the ferroelectric liquid crystal can be effectively controlled. In addition, since the photo-alignment process is a non-contact alignment process, there is no generation of static electricity or dust, and it is useful in that the quantitative alignment process can be controlled.

On the other hand, when the first alignment film is a rubbing film subjected to rubbing treatment, it is possible to effectively suppress the occurrence of zigzag defects and hairpin defects.
In general, a ferroelectric liquid crystal having a phase sequence passing through an SmA phase has a chevron structure in which a smectic layer is shrunk in order to compensate for the volume change in the process of phase change, and the smectic layer has a reduced interval. Domains having different major axis directions of liquid crystal molecules are formed depending on the bending direction, and alignment defects called zigzag defects and hairpin defects are likely to occur at the boundary surfaces. In order to prevent the occurrence of zigzag defects and hairpin defects, it is effective to increase the pretilt angle.
With the rubbing film, a relatively high pretilt angle can be realized. Therefore, the occurrence of zigzag defects and hairpin defects can be effectively suppressed by using the first alignment film as a rubbing film.

  Especially, when not performing the below-mentioned reactive liquid crystal layer formation process, it is preferable to form a 1st alignment film by a photo-alignment process. This is because, as described above, when the first alignment film is subjected to photo-alignment treatment, the direction of spontaneous polarization of the ferroelectric liquid crystal can be effectively controlled.

  Moreover, when performing the reactive liquid crystal layer formation process mentioned later, it is preferable that the 1st alignment film is a rubbing film by which the rubbing process was carried out. When the reactive liquid crystal layer is formed on the rubbing film, the reactive liquid crystal is aligned by the alignment regulating force of the rubbing film. A pretilt angle can be realized. Therefore, when the first alignment film is a rubbing film and a reactive liquid crystal layer is formed on the rubbing film, the occurrence of zigzag defects and hairpin defects can be effectively suppressed.

  Hereinafter, a method for forming the first alignment film by the photo-alignment process and a method for forming the first alignment film by the rubbing process will be described.

(I) Photo-alignment treatment When the first alignment film is formed by the photo-alignment treatment, a photo-alignable material is applied on the first electrode layer to form a coating film, and light with polarization controlled on the coating film The first alignment film can be formed by causing photoexcitation reaction (decomposition, isomerization, dimerization) to impart anisotropy to the coating film.

The photo-alignment material used in the present invention is not particularly limited as long as it has an effect of aligning ferroelectric liquid crystals (photoalignment) by irradiating light and causing a photoexcitation reaction. is not. This photo-alignable material is largely divided into a photoreactive material that imparts anisotropy to the alignment film by causing a photoreaction, and a photoisomerism that imparts anisotropy to the alignment film by causing a photoisomerization reaction. It can be divided into chemical materials.
Hereinafter, the photoreactive material and the photoisomerizable material will be described.

(Photoreactive material)
The photoreactive material used in the present invention is not particularly limited as long as it imparts anisotropy to the alignment film by causing a photoreaction, but it causes a photodimerization reaction or a photodecomposition reaction. It is preferable that the alignment film is provided with anisotropy.

  Here, the photodimerization reaction refers to a reaction in which reaction sites aligned in the polarization direction by light irradiation undergo radical polymerization and two molecules are polymerized. This reaction stabilizes the alignment in the polarization direction and is anisotropic to the alignment film. It is possible to impart sex. The photodegradation reaction is a reaction that decomposes molecular chains such as polyimide oriented in the polarization direction by light irradiation. This reaction leaves molecular chains oriented in the direction perpendicular to the polarization direction, and is anisotropic to the alignment film. It is possible to impart sex. Among them, it is more preferable to use a photodimerization-type material that imparts anisotropy to the alignment film by a photodimerization reaction because of high exposure sensitivity and a wide range of material selection.

  The photodimerization type material is not particularly limited as long as it can impart anisotropy to the alignment film by a photodimerization reaction, but has a radical polymerizable functional group and has a polarization direction. It is preferable to contain a photodimerization reactive compound having dichroism with different absorption. This is because by radical polymerization of the reaction site oriented in the polarization direction, the orientation of the photodimerization reactive compound is stabilized and anisotropy can be easily imparted to the orientation film.

  Examples of the photodimerization reactive compound having such characteristics include a dimerization reactive polymer having at least one reactive site selected from cinnamate ester, coumarin, quinoline, chalcone group and cinnamoyl group as a side chain. Can do.

  Among these, the photodimerization reactive compound is preferably a dimerization reactive polymer containing cinnamate, coumarin or quinoline as a side chain. This is because anisotropy can be easily imparted to the alignment film by radical polymerization of α and β unsaturated ketone double bonds aligned in the polarization direction as reaction sites.

  The main chain of the dimerization reactive polymer is not particularly limited as long as it is generally known as a polymer main chain, but the reaction sites of the side chains such as aromatic hydrocarbon groups are not limited. It is preferable that it does not have a substituent containing a lot of π electrons that hinders the interaction.

  The weight average molecular weight of the dimerization reactive polymer is not particularly limited, but is preferably in the range of 5,000 to 40,000, and is preferably in the range of 10,000 to 20,000. Is more preferable. The weight average molecular weight can be measured by a gel permeation chromatography (GPC) method. If the weight-average molecular weight of the dimerization reactive polymer is too small, it may not be possible to impart appropriate anisotropy to the alignment film. On the other hand, if it is too large, the viscosity of the coating liquid at the time of forming the first alignment film increases, and it may be difficult to form a uniform coating film.

  An example of the dimerization reactive polymer is a compound represented by the following formula (4).

In the above formula (4), M ¹¹ and M ¹² each independently represent a monomer unit of a homopolymer or a copolymer. Examples thereof include ethylene, acrylate, methacrylate, 2-chloroacrylate, acrylamide, methacrylamide, 2-chloroacrylamide, styrene derivatives, maleic acid derivatives, and siloxane. M ¹² may be acrylonitrile, methacrylonitrile, methacrylate, methyl methacrylate, hydroxyalkyl acrylate or hydroxyalkyl methacrylate. x and y represent the molar ratio of each monomer unit in the case of a copolymer, and are numbers satisfying 0 <x ≦ 1, 0 ≦ y <1 and satisfying x + y = 1, respectively. It is. n represents an integer of 4 to 30,000. D ¹ and D ² represent spacer units.

R ¹ is a group represented by -A ^1- (Z ¹ -B ¹ ) _z -Z ^2- , and R ² is represented by -A ^1- (Z ¹ -B ¹ ) _z -Z ^3-. It is a group. Here, A ¹ and B ¹ are each independently a covalent single bond, pyridine-2,5-diyl, pyrimidine-2,5-diyl, 1,4-cyclohexylene, 1,3-dioxane-2, It represents 5-diyl or 1,4-phenylene which may have a substituent. Z ¹ and Z ² are each independently a covalent single bond, —CH ₂ —CH ₂ —, —CH ₂ O—, —OCH ₂ —, —CONR—, —RNCO—, —COO— or — Represents OOC-. R is a hydrogen atom or a lower alkyl group, and Z ³ is a hydrogen atom or an alkyl or alkoxy having 1 to 12 carbon atoms, which may have a substituent, cyano, nitro, or halogen. z is an integer of 0-4. E ¹ represents a photodimerization reaction site, and examples thereof include cinnamic acid ester, coumarin, quinoline, chalcone group, cinnamoyl group and the like. j and k are each independently 0 or 1.

  Specific examples of such a dimerization reactive polymer include compounds represented by the following formulas (5) to (8).

  More specific examples of the dimerization reactive polymer include compounds represented by the following formulas (9) to (12).

  As the photodimerization reactive compound, various photodimerization reaction sites and substituents can be selected from the above-mentioned compounds according to the required characteristics. Moreover, the photodimerization reactive compound can also be used individually by 1 type or in combination of 2 or more types.

  Moreover, the photodimerization-type material may contain the additive in the range which does not prevent the photo-alignment property of a 1st alignment film other than the said photodimerization reactive compound. Examples of the additive include a polymerization initiator and a polymerization inhibitor.

  The polymerization initiator or polymerization inhibitor may be appropriately selected from generally known compounds according to the type of the photodimerization reactive compound. The addition amount of the polymerization initiator or the polymerization inhibitor is preferably in the range of 0.001% by mass to 20% by mass, and in the range of 0.1% by mass to 5% by mass with respect to the photodimerization reactive compound. It is more preferable that This is because if the addition amount of the polymerization initiator or polymerization inhibitor is too small, the polymerization may not be started (prohibited), whereas if too large, the reaction may be inhibited.

  On the other hand, examples of the photodecomposable material utilizing a photodecomposition reaction include polyimide “RN1199” manufactured by Nissan Chemical Industries, Ltd.

  The wavelength region of light that causes photoreaction of the photoreactive material is preferably in the range of ultraviolet light, that is, in the range of 10 nm to 400 nm, and more preferably in the range of 250 nm to 380 nm.

(Photoisomerization type material)
The photoisomerization type material used in the present invention is not particularly limited as long as it imparts anisotropy to the alignment film by causing a photoisomerization reaction, but it causes a photoisomerization reaction. It is preferable that it contains a photoisomerization reactive compound that imparts anisotropy to the alignment film. By including such a photoisomerization-reactive compound, a stable isomer among a plurality of isomers is increased by light irradiation, whereby anisotropy can be easily imparted to the alignment film. is there.

  The photoisomerization reactive compound is not particularly limited as long as it is a material having the above-mentioned characteristics, but has a dichroism that makes absorption different depending on the polarization direction, and can be irradiated by light irradiation. It is preferable that it causes an isomerization reaction. This is because anisotropy can be easily imparted to the alignment film by causing isomerization of the reaction site oriented in the polarization direction of the photoisomerization reactive compound having such characteristics.

  Further, the photoisomerization reaction in which the photoisomerization reactive compound is generated is preferably a cis-trans isomerization reaction. This is because isomers of either the cis form or the trans form are increased by light irradiation, whereby anisotropy can be imparted to the alignment film.

  Examples of such photoisomerization-reactive compounds include monomolecular compounds and polymerizable monomers that are polymerized by light or heat. These may be selected as appropriate according to the type of ferroelectric liquid crystal used. However, it is possible to stabilize the anisotropy by polymerizing after imparting anisotropy to the alignment film by light irradiation. Since it can be performed, it is preferable to use a polymerizable monomer. Among such polymerizable monomers, an acrylate monomer and a methacrylate monomer are preferable because anisotropy is imparted to the alignment film and the polymer can be easily polymerized while maintaining the anisotropy in a good state.

  The polymerizable monomer may be a monofunctional monomer or a polyfunctional monomer. However, since the anisotropy of the alignment film due to polymerization becomes more stable, it is a bifunctional monomer. Preferably there is.

  Specific examples of such a photoisomerization-reactive compound include compounds having a cis-trans isomerization-reactive skeleton such as an azobenzene skeleton or a stilbene skeleton.

  In this case, the number of cis-trans isomerization reactive skeletons contained in the molecule may be one or two or more, but the alignment control of the ferroelectric liquid crystal becomes easy. Two are preferable.

  The cis-trans isomerization reactive skeleton may have a substituent in order to further enhance the interaction with the liquid crystal molecules. The substituent is not particularly limited as long as it can enhance the interaction with the liquid crystal molecules and does not interfere with the orientation of the cis-trans isomerization reactive skeleton, and examples thereof include a carboxyl group and a sulfonic acid. A sodium group, a hydroxyl group, etc. are mentioned. These structures can be appropriately selected depending on the type of ferroelectric liquid crystal used.

In addition to the cis-trans isomerization reactive skeleton, the photoisomerization reactive compound contains many π electrons such as aromatic hydrocarbon groups so that the interaction with the liquid crystal molecules can be further enhanced. It may have an included group, and the cis-trans isomerization reactive skeleton and the aromatic hydrocarbon group may be bonded via a bonding group. The bonding group is not particularly limited as long as it can enhance the interaction with the liquid crystal molecule. For example, —COO—, —OCO—, —O—, —C≡C—, —CH ₂ —CH _2- , —CH ₂ O—, —OCH ₂ — and the like can be mentioned.

  In addition, when using a polymerizable monomer as a photoisomerization reactive compound, it is preferable to have the said cis-trans isomerization reactive skeleton as a side chain. By having the cis-trans isomerization reactive skeleton as a side chain, the effect of anisotropy imparted to the alignment film becomes larger, and it is particularly suitable for controlling the alignment of ferroelectric liquid crystals. Because it becomes. In this case, the aromatic hydrocarbon group or bonding group contained in the molecule is contained in the side chain together with the cis-trans isomerization reactive skeleton so that the interaction with the liquid crystal molecule is enhanced. It is preferable.

  Further, the side chain of the polymerizable monomer may have an aliphatic hydrocarbon group such as an alkylene group as a spacer so that the cis-trans isomerization reactive skeleton can be easily oriented.

  Among the photoisomerization reactive compounds of the monomolecular compound or polymerizable monomer as described above, the photoisomerization reactive compound used in the present invention is preferably a compound having an azobenzene skeleton in the molecule. This is because the azobenzene skeleton contains a lot of π electrons, and thus has a high interaction with liquid crystal molecules and is particularly suitable for controlling the alignment of ferroelectric liquid crystals.

  Hereinafter, the reason why the azobenzene skeleton can impart anisotropy to the alignment film by causing a photoisomerization reaction will be described. First, when the azobenzene skeleton is irradiated with linearly polarized ultraviolet light, the trans azobenzene skeleton having the molecular long axis oriented in the polarization direction is changed to a cis isomer as shown in the following formula.

  Since the cis isomer of the azobenzene skeleton is chemically unstable compared to the trans isomer, it thermally or absorbs visible light and returns to the trans isomer. Whether to become the right transformer body occurs with the same probability. Therefore, if the ultraviolet light is continuously absorbed, the ratio of the right-side trans isomer increases, and the average orientation direction of the azobenzene skeleton becomes perpendicular to the polarization direction of the ultraviolet light. In the present invention, by utilizing this phenomenon, the alignment direction of the azobenzene skeleton can be aligned, anisotropy can be imparted to the alignment film, and the alignment of liquid crystal molecules on the film can be controlled.

  Among such compounds having an azobenzene skeleton in the molecule, examples of the monomolecular compound include compounds represented by the following formula (13).

In the above formula (13), R ⁴¹ each independently represents a hydroxy group. R ⁴² is _{^{- (A 41 -B 41 -A 41}} ) m - (D 41) n - represents a linking group represented ^{by, R 43} is _{^{(D 41) n - (A}} 41 -B 41 -A 41) _m represents a linking group represented by-. Here, A ⁴¹ represents a divalent hydrocarbon group, B ⁴¹ represents —O—, —COO—, —OCO—, —CONH—, —NHCO—, —NHCOO— or —OCONH—, and m represents Represents an integer of 0 to 3; D ⁴¹ represents a divalent hydrocarbon group when m is 0, and —O—, —COO—, —OCO—, —CONH—, —NHCO—, —NHCOO— when m is an integer of 1 to 3. Alternatively, -OCONH- is represented, and n represents 0 or 1. R ⁴⁴ each independently represents a halogen atom, a carboxy group, a halogenated methyl group, a halogenated methoxy group, a cyano group, a nitro group, a methoxy group or a methoxycarbonyl group. However, the carboxy group may form a salt with an alkali metal. R ⁴⁵ each independently represents a carboxy group, a sulfo group, a nitro group, an amino group or a hydroxy group. However, the carboxy group or the sulfo group may form a salt with the alkali metal.

  Specific examples of the compound represented by the above formula (13) include compounds represented by the following formulas (14) to (17).

  Examples of the polymerizable monomer having the azobenzene skeleton as a side chain include compounds represented by the following formula (18).

In the above formula (18), each R ⁵¹ is independently (meth) acryloyloxy group, (meth) acrylamide group, vinyloxy group, vinyloxycarbonyl group, vinyliminocarbonyl group, vinyliminocarbonyloxy group, vinyl group, An isopropenyloxy group, an isopropenyloxycarbonyl group, an isopropenyliminocarbonyl group, an isopropenyliminocarbonyloxy group, an isopropenyl group, or an epoxy group is represented. R ⁵² is _{^{- (A 51 -B 51 -A 51}} ) m - (D 51) n - represents a linking group represented ^{by, R 53} is _{^{(D 51) n - (A}} 51 -B 51 -A 51) _m represents a linking group represented by-. Here, A ⁵¹ represents a divalent hydrocarbon group, B ⁵¹ represents —O—, —COO—, —OCO—, —CONH—, —NHCO—, —NHCOO— or —OCONH—, and m represents Represents an integer of 0 to 3; D ⁵¹ represents a divalent hydrocarbon group when m is 0, and when m is an integer of 1 to 3, —O—, —COO—, —OCO—, —CONH—, —NHCO—, —NHCOO— Alternatively, -OCONH- is represented, and n represents 0 or 1. R ⁵⁴ each independently represents a halogen atom, a carboxy group, a halogenated methyl group, a halogenated methoxy group, a cyano group, a nitro group, a methoxy group or a methoxycarbonyl group. However, the carboxy group may form a salt with an alkali metal. R ⁵⁵ each independently represents a carboxy group, a sulfo group, a nitro group, an amino group or a hydroxy group. However, the carboxy group or the sulfo group may form a salt with the alkali metal.

  Specific examples of the compound represented by the above formula (18) include compounds represented by the following formulas (19) to (22).

  In the present invention, various cis-trans isomerization reactive skeletons and substituents can be selected from such photoisomerization reactive compounds according to required characteristics. In addition, these photoisomerization reactive compounds can also be used individually by 1 type or in combination of 2 or more types.

  In addition to the photoisomerization reactive compound, the photoisomerization type material may contain an additive within a range that does not interfere with the photoalignment of the alignment film. When a polymerizable monomer is used as the photoisomerization reactive compound, examples of the additive include a polymerization initiator and a polymerization inhibitor.

  The polymerization initiator or polymerization inhibitor may be appropriately selected from generally known compounds according to the type of photoisomerization reactive compound. The addition amount of the polymerization initiator or polymerization inhibitor is preferably in the range of 0.001% by mass to 20% by mass, and in the range of 0.1% by mass to 5% by mass with respect to the photoisomerization reactive compound. More preferably, it is within. This is because if the addition amount of the polymerization initiator or polymerization inhibitor is too small, the polymerization may not be started (prohibited), whereas if too large, the reaction may be inhibited.

  The wavelength region of the light that causes the photoisomerization reaction of the photoisomerizable material is preferably in the ultraviolet light range, that is, in the range of 10 nm to 400 nm, and more preferably in the range of 250 nm to 380 nm. .

(Photo-alignment processing method)
Next, the photo-alignment processing method will be described. First, a first alignment film forming coating solution obtained by diluting the above-described photo-alignment material with an organic solvent is applied on the first electrode layer and dried.

  The content of the photodimerization reactive compound or photoisomerization reactive compound in the first alignment film forming coating solution is preferably in the range of 0.05% by mass to 10% by mass, and 0.2% by mass. More preferably, it is in the range of% to 2% by mass. If the content is less than the above range, it will be difficult to impart appropriate anisotropy to the alignment film. Conversely, if the content is more than the above range, the viscosity of the coating liquid will increase, so a uniform coating film will be formed. It is because it becomes difficult to form.

  As a coating method of the first alignment film forming coating solution, for example, spin coating method, roll coating method, rod bar coating method, spray coating method, air knife coating method, slot die coating method, wire bar coating method, ink jet method, A flexographic printing method, a screen printing method, or the like can be used.

  The thickness of the film obtained by applying the first alignment film forming coating solution is preferably in the range of 1 nm to 1000 nm, more preferably in the range of 3 nm to 100 nm. This is because if the film thickness is thinner than the above range, sufficient optical alignment may not be obtained, and conversely if the film thickness is thicker than the above range, it may be disadvantageous in terms of cost.

  The obtained film can impart anisotropy by causing a photoexcitation reaction by irradiating light with polarization controlled. The wavelength region of the light to be irradiated may be appropriately selected according to the constituent material of the alignment film to be used, but is preferably in the ultraviolet light range, that is, in the range of 100 nm to 400 nm, more preferably 250 nm to It is in the range of 380 nm. The polarization direction is not particularly limited as long as it can cause the photoexcitation reaction.

  Furthermore, when a polymerizable monomer is used as the photo-alignable material among the above photoisomerization-reactive compounds, it is polymerized by heating after being subjected to a photo-alignment treatment and applied to the alignment film. Anisotropy can be stabilized.

(Ii) Rubbing treatment As a rubbing treatment method, a rubbing alignment material is applied on the first electrode layer and cured, and the obtained film is rubbed in a certain direction with a rubbing cloth to impart anisotropy to the alignment film. Can be used.

  The rubbing alignment material used for the rubbing film is not particularly limited as long as it can impart anisotropy to the alignment film by rubbing treatment. For example, polyimide, polyamide, polyamideimide, polyether Examples include imide, polyvinyl alcohol, and polyurethane. These may be used alone or in combination of two or more.

  Especially, it is preferable that a rubbing film | membrane contains a polyimide, and it is especially preferable to contain the polyimide which carried out the dehydration ring closure (imidation) of the polyamic acid.

A polyamic acid can be synthesized by reacting a diamine compound with an acid dianhydride.
Examples of the diamine compound used when synthesizing the polyamic acid include alicyclic diamines, carbocyclic aromatic diamines, heterocyclic diamines, aliphatic diamines, and aromatic diamines.

  Examples of the alicyclic diamine include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4′-diaminodicyclohexylmethane, 4,4′-diamino-3,3′-dimethyldicyclohexane, and isophorone diamine. Etc.

  Examples of the carbocyclic aromatic diamines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, diaminotoluenes (specifically 2,4-diaminotoluene), 1,4-diamino- 2-methoxybenzene, diaminoxylenes (specifically 1,3-diamino-2,4-dimethylbenzene), 1,3-diamino-4-chlorobenzene, 1,4-diamino-2,5-dichlorobenzene 1,4-diamino-4-isopropylbenzene, 2,2′-bis (4-aminophenyl) propane, 4,4′-diaminodiphenylmethane, 2,2′-diaminostilbene, 4,4′-diaminostilbene, 4,4'-diaminodiphenyl ether, 4,4'-diphenylthioether, 4,4'-diaminodiphenyl sulfone, , 3'-diaminodiphenylsulfone, 4,4'-diaminobenzoic acid phenyl ester, 4,4'-diaminobenzophenone, 4,4'-diaminobenzyl, bis (4-aminophenyl) phosphine oxide, bis (3-amino Phenyl) sulfone, bis (4-aminophenyl) phenylphosphine oxide, bis (4-aminophenyl) cyclohexylphosphine oxide, N, N-bis (4-aminophenyl) -N-phenylamine, N, N-bis (4 -Aminephenyl) -N-methylamine, 4,4'-diaminodiphenylurea, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, 1,5-diaminoanthraquinone, diaminofluorenes (specifically, 2 , 6-Diaminofluorene), bis (4-aminophenyl) diethyl Lan, bis (4-aminophenyl) dimethylsilane, 3,4'-diaminodiphenyl ether, benzidine, 2,2'-dimethylbenzidine, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [ 4- (4-aminophenoxy) phenyl] sulfone, 4,4′-bis (4-aminophenoxy) biphenyl, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 1,4- Examples thereof include bis (4-aminophenoxy) benzene and 1,3-bis (4-aminophenoxy) benzene.

  Examples of the heterocyclic diamines include 2,6-diaminopyridine, 2,4-diaminopyridine, 2,4-diamino-s-triazine, 2,5-diaminodibenzofuran, 2,7-diaminocarbazole, 3, Examples include 6-diaminocarbazole, 3,7-diaminophenothiazine, 2,5-diamino-1,3,4-thiadiazole, 2,4-diamino-6-phenyl-s-triazine.

  Examples of the aliphatic diamine include 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,8-diaminooctane, 1,10-diaminodecane, 1,3-diamino-2,2-dimethylpropane, 1,6-diamino-2,5-dimethylhexane, 1,5-diamino-2,4-dimethylheptane, 1,7- Examples include diamino-3-methylheptane, 1,9-diamino-5-methylnonane, 2,11-diaminododecane, 1,12-diaminooctadecane, 1,2-bis (3-aminopropoxy) ethane and the like.

  Examples of the aromatic diamine include those having a long-chain alkyl or perfluoro group represented by the structure of the following formula.

Here, in the above formula, R ²¹ represents a monovalent organic group containing a long-chain alkyl group, a long-chain alkyl group or a perfluoroalkyl group having 5 or more carbon atoms, preferably 5 to 20 carbon atoms.

  Examples of the acid dianhydride used as a raw material when synthesizing a polyamic acid include aromatic acid dianhydrides and alicyclic acid dianhydrides.

  Examples of aromatic dianhydrides include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, and 2,2 ′, 3,3′-biphenyltetracarboxylic acid. Dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,3,3 ′, 4′- Benzophenonetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid A dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride etc. are mentioned.

  Examples of the alicyclic acid dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,4 , 5-tetrahydrofurantetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,4-dicarboxy-1-cyclohexylsuccinic dianhydride, 3,4-dicarboxy- Examples include 1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride, and the like.

  These acid dianhydrides may be used alone or in combination of two or more. From the viewpoint of polymer transparency, it is preferable to use an alicyclic acid dianhydride.

  The polyamic acid is a mixture of the above diamine compound and acid dianhydride in the presence of an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 80 ° C., for 30 minutes to 24 hours, preferably 1 hour. It can synthesize | combine by making it react for 10 hours.

  As a method of obtaining a polyimide film using polyamic acid, after polyamic acid is formed, all or part of the ring is dehydrated (imidized) by heating or a catalyst, or all polyamic acid is heated or by a catalyst. Alternatively, a method of forming a film after forming a soluble polyimide after partially dehydrating and ring-closing (imidizing) to form a soluble polyimide can be mentioned. Especially, since the soluble polyimide obtained by imidizing polyamic acid is excellent in storage stability, the method of forming a film of soluble polyimide is preferable.

  Examples of a method for performing an imidization reaction for converting a polyamic acid into a soluble polyimide include thermal imidation in which a polyamic acid solution is heated as it is, and chemical imidation in which a catalyst is added to the polyamic acid solution to perform imidization. . Among these, the chemical imidation in which the imidization reaction proceeds at a relatively low temperature is preferable because the molecular weight of the resulting soluble polyimide is less likely to decrease.

  In the chemical imidization reaction, polyamic acid in an organic solvent is 0.5 to 30 mol times, preferably 1 to 20 mol times the base catalyst of the amic acid group, and 0.5 to 50 mol times of the amic acid group. The reaction is preferably performed in the presence of 1 to 30 moles of acid anhydride at a temperature of -20 ° C to 250 ° C, preferably 0 ° C to 200 ° C for 1 hour to 100 hours. This is because if the amount of the base catalyst or acid anhydride is small, the reaction does not proceed sufficiently, and if it is too large, it is difficult to completely remove the reaction after the reaction is completed.

Examples of the base catalyst used in the chemical imidation reaction include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Of these, pyridine is preferable because it has a basicity suitable for advancing the reaction.
Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Among these, use of acetic anhydride is preferable because purification after completion of the reaction becomes easy.

  As an organic solvent for performing the imidization reaction, a solvent used at the time of polyamic acid synthesis can be used.

  The imidization rate by chemical imidation can be controlled by adjusting the amount of catalyst and the reaction temperature. Among these, the imidation ratio is preferably 0.1% to 99%, more preferably 5% to 90%, and further preferably 30% to 70% of the number of moles of all polyamic acids. This is because if the imidization rate is too low, the storage stability is deteriorated, and if it is too high, the solubility is poor and may be precipitated.

  As the material for the rubbing film, “SE-5291”, “SE-7992”, and “SE-7492” manufactured by Nissan Chemical Industries, Ltd. are preferably used.

  As a method for applying the rubbing alignment material, for example, a roll coating method, a rod bar coating method, a slot die coating method, a wire bar coating method, an ink jet method, a flexographic printing method, a screen printing method, or the like can be used.

  As the rubbing cloth, for example, a cloth made of a fiber such as nylon resin, vinyl resin, rayon, or cotton can be used. For example, by rotating a drum wound with such a rubbing cloth and bringing it into contact with the surface of the film using the rubbing alignment material, fine grooves are formed in one direction on the film surface, and the alignment film is anisotropic. Sex is imparted.

  The thickness of the rubbing film is set to about 1 nm to 1000 nm, and preferably in the range of 50 nm to 100 nm.

(Iii) 1st base material The 1st base material used for this invention will not be specifically limited if generally used as a base material of a liquid crystal display element, For example, a glass plate, a plastic plate, etc. are preferable. Can be mentioned.

(Iv) First electrode layer The first electrode layer used in the present invention is not particularly limited as long as it is generally used as an electrode of a liquid crystal display element, but the first electrode layer of the liquid crystal side substrate. It is preferable that at least one of the second electrode layers of the counter substrate is formed of a transparent conductor. Preferred examples of the transparent conductor material include indium oxide, tin oxide, indium tin oxide (ITO), and the like.

  When the liquid crystal display element obtained by the present invention is driven by an active matrix method using TFTs, one of the liquid crystal side substrate and the counter substrate is provided with the entire surface common electrode formed of the transparent conductor, and the other The gate electrode and the source electrode are arranged in a matrix, and a TFT element and a pixel electrode are provided in a portion surrounded by the gate electrode and the source electrode.

  Examples of the method for forming the first electrode layer include chemical vapor deposition (CVD), physical vapor deposition (PVD) such as sputtering, ion plating, and vacuum deposition.

(2) Reactive liquid crystal layer forming step The liquid crystal side substrate preparing step in the present invention includes a reactive liquid crystal layer forming step of forming a reactive liquid crystal layer formed by fixing a reactive liquid crystal on the first alignment film. preferable. When the reactive liquid crystal layer is formed on the first alignment film, the reactive liquid crystal is aligned by the first alignment film, and the alignment state of the reactive liquid crystal is changed by, for example, irradiating ultraviolet rays to polymerize the reactive liquid crystal. Can be immobilized. Therefore, the first liquid crystal layer can be provided with the alignment regulating force of the first alignment film, and the reactive liquid crystal layer can act as an alignment film for aligning the ferroelectric liquid crystal. Further, since the reactive liquid crystal is fixed, it has an advantage that it is not affected by temperature or the like. In addition, reactive liquid crystals are relatively similar in structure to ferroelectric liquid crystals, and the interaction with ferroelectric liquid crystals becomes stronger, so that the direction of spontaneous polarization of ferroelectric liquid crystals can be controlled effectively. Can do.

  When the reactive liquid crystal layer forming step is performed in the liquid crystal side substrate preparing step, the ferroelectric liquid crystal is applied on the reactive liquid crystal layer in the liquid crystal applying step described later.

  The reactive liquid crystal used in the present invention preferably exhibits a nematic phase. This is because the nematic phase is relatively easy to control the alignment among the liquid crystal phases.

  The reactive liquid crystal preferably contains a polymerizable liquid crystal material. This is because the alignment state of the reactive liquid crystal can be fixed. As the polymerizable liquid crystal material, any of a polymerizable liquid crystal monomer, a polymerizable liquid crystal oligomer, and a polymerizable liquid crystal polymer can be used, and among them, a polymerizable liquid crystal monomer is preferably used. The polymerizable liquid crystal monomer can be aligned at a lower temperature than other polymerizable liquid crystal materials, that is, a polymerizable liquid crystal oligomer and a polymerizable liquid crystal polymer, and has high sensitivity in alignment, and can be easily aligned. Because you can.

  The polymerizable liquid crystal monomer is not particularly limited as long as it is a liquid crystal monomer having a polymerizable functional group, and examples thereof include a monoacrylate monomer and a diacrylate monomer. These polymerizable liquid crystal monomers may be used alone or in combination of two or more.

  Examples of the monoacrylate monomer include compounds represented by the following formulas (1) and (2).

In the above formulas (1) and (2), A, B, D, E and F represent benzene, cyclohexane or pyrimidine, and these may have a substituent such as halogen. A and B, or D and E may be bonded via a bonding group such as an acetylene group, a methylene group, or an ester group. M ¹ and M ² may be any of a hydrogen atom, an alkyl group having 3 to 9 carbon atoms, an alkoxycarbonyl group having 3 to 9 carbon atoms, or a cyano group. Furthermore, the acryloyloxy group at the end of the molecular chain and A or D may be bonded via a spacer such as an alkylene group having 3 to 6 carbon atoms.

  Examples of the diacrylate monomer include a compound represented by the following formula (23).

In the above formula (23), Z ³¹ and Z ³² are each independently directly bonded —COO—, —OCO—, —O—, —CH ₂ CH ₂ —, —CH═CH—, —C ≡C—, —OCH ₂ —, —CH ₂ O—, —CH ₂ CH ₂ COO—, —OCOCH ₂ CH ₂ —, wherein R ³¹ , R ³² and R ³³ each independently represent hydrogen or carbon number Represents 1-5 alkyl. K and m represent 0 or 1, and n represents an integer in the range of 2 to 8. R ³¹ , R ³² and R ³³ are each independently alkyl having 1 to 5 carbons when k = 1, and each independently being hydrogen or alkyl having 1 to 5 carbons when k = 0. Preferably there is. R ³¹ , R ³² and R ³³ may be the same as each other.

  Specific examples of the compound represented by the above formula (23) include a compound represented by the following formula (24).

In the above formula (24), Z ²¹ and Z ²² are each independently directly bonded —COO—, —OCO—, —O—, —CH ₂ CH ₂ —, —CH═CH—, —C Represents ≡C—, —OCH ₂ —, —CH ₂ O—, —CH ₂ CH ₂ COO—, —OCOCH ₂ CH ₂ —. M represents 0 or 1, and n represents an integer in the range of 2-8.

  Examples of the diacrylate monomer also include compounds represented by the following formulas (25) and (3).

In the above formulas (25) and (3), X and Y are hydrogen, alkyl having 1 to 20 carbons, alkenyl having 1 to 20 carbons, alkyloxy having 1 to 20 carbons, or alkyl having 1 to 20 carbons. It represents oxycarbonyl, formyl, alkylcarbonyl having 1 to 20 carbons, alkylcarbonyloxy having 1 to 20 carbons, halogen, cyano or nitro. M represents an integer in the range of 2-20. In the above formula (25), X is preferably an alkyloxycarbonyl having 1 to 20 carbon atoms, methyl or chlorine, and especially an alkyloxycarbonyl having 1 to 20 carbon atoms, particularly CH ₃ (CH ₂ ) _4. OCO is preferred.

  Among these, compounds represented by the above formulas (23) and (25) are preferably used. In particular, a compound represented by the above formula (25) is preferable. Specific examples include “Adeka Kiracol PLC-7183”, “Adeka Kiracol PLC-7209”, and “Adeka Kiracol PLC-7218” manufactured by Asahi Denka Kogyo Co., Ltd.

  Of the polymerizable liquid crystal monomers, diacrylate monomers are preferred. This is because the diacrylate monomer can be easily polymerized while maintaining the orientation state in a good state.

  The polymerizable liquid crystal monomer described above may not be one that exhibits a nematic phase. These polymerizable liquid crystal monomers may be used as a mixture of two or more kinds as described above, because the composition in which these are mixed, that is, the reactive liquid crystal may exhibit a nematic phase. It is.

  Furthermore, you may add a photoinitiator, a polymerization inhibitor, etc. to the said reactive liquid crystal as needed. For example, when polymerizing a polymerizable liquid crystal material by electron beam irradiation, a photopolymerization initiator may not be necessary, but in the case of polymerization by, for example, ultraviolet irradiation, usually photopolymerization is started. An agent is used to promote polymerization.

  Examples of the photopolymerization initiator include benzyl (also referred to as bibenzoyl), benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-benzoyl-4′-methyldiphenyl sulfide, benzylmethyl ketal, Dimethylaminomethyl benzoate, 2-n-butoxyethyl-4-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 3,3′-dimethyl-4-methoxybenzophenone, methylobenzoyl formate, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 1- (4-dodecyl) Phenyl) 2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy 2-methylpropan-1-one, 2-chlorothioxanthone, 2,4-diethylthioxanthone 2,4-diisopropylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propoxythioxanthone, etc. Can do. In addition to the photopolymerization initiator, it is also possible to add a sensitizer as long as the object of the present invention is not impaired.

  Moreover, as addition amount of a photoinitiator, it adds to the said reactive liquid crystal in the range of about 0.01-20 mass%, Preferably it is 0.1-10 mass%, More preferably, it is 0.5-5 mass%. can do.

  In the present invention, the reactive liquid crystal layer-forming coating liquid containing the reactive liquid crystal is applied on the first alignment film, subjected to an alignment treatment, and the reaction is performed by fixing the alignment state of the reactive liquid crystal. A liquid crystal layer can be formed. Alternatively, a reactive liquid crystal layer may be formed by forming a dry film or the like in advance and laminating the film on the first alignment film. Especially, the method of apply | coating the coating liquid for reactive liquid crystal layer formation is preferable at the point with a simple process.

The coating liquid for forming a reactive liquid crystal layer can be prepared by dissolving or dispersing reactive liquid crystals in a solvent.
The solvent used in the coating liquid for forming the reactive liquid crystal layer is not particularly limited as long as it can dissolve or disperse the reactive liquid crystal and the like and does not inhibit the alignment ability of the first alignment film. is not. Examples of such a solvent include hydrocarbons such as benzene, toluene, xylene, n-butylbenzene, diethylbenzene, and tetralin; ethers such as methoxybenzene, 1,2-dimethoxybenzene, and diethylene glycol dimethyl ether; acetone, methyl ethyl ketone, Ketones such as methyl isobutyl ketone, cyclohexanone and 2,4-pentanedione; esters such as ethyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate and γ-butyrolactone; 2-pyrrolidone, N-methyl-2 Amide solvents such as pyrrolidone, dimethylformamide, dimethylacetamide; t-butyl alcohol, diacetone alcohol, glycerin, monoacetin, ethylene glyco Le, triethylene glycol, or hexylene glycol; phenols, phenol para chlorophenol and the like; methyl cellosolve, ethyl cellosolve, butyl cellosolve, cellosolve such as ethylene glycol monomethyl ether acetate; and the like. These solvents may be used alone or in combination of two or more.

  Further, if only a single type of solvent is used, the solubility of the reactive liquid crystal or the like may be insufficient, or the first alignment film may be eroded as described above. In this case, this inconvenience can be avoided by using a mixture of two or more solvents. Among the above-mentioned solvents, hydrocarbons and glycol monoether acetate solvents are preferable as the sole solvent, and mixed solvents of ethers or ketones and glycol solvents are preferable as the mixed solvent. .

  The solid content concentration of the coating liquid for forming the reactive liquid crystal layer cannot be defined unconditionally because it depends on the solubility of the reactive liquid crystal and the thickness of the reactive liquid crystal layer, but usually 0.1 to 40% by mass, Preferably, it adjusts in the range of 1-20 mass%. If the solid content concentration of the reactive liquid crystal layer-forming coating liquid is lower than the above range, the reactive liquid crystal may be difficult to align. Conversely, the solid content concentration of the reactive liquid crystal layer forming coating liquid is within the above range. This is because if it is higher, the viscosity of the reactive liquid crystal layer-forming coating solution becomes high, and it may be difficult to form a uniform coating film.

Furthermore, the following compounds can be added to the reactive liquid crystal layer-forming coating solution as long as the object of the present invention is not impaired. Examples of compounds that can be added include polyester (meth) acrylate obtained by reacting (meth) acrylic acid with a polyester prepolymer obtained by condensing polyhydric alcohol and monobasic acid or polybasic acid; A polyurethane (meth) acrylate obtained by reacting a compound having two isocyanate groups with each other and then reacting the reaction product with (meth) acrylic acid; bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak Type epoxy resins, polycarboxylic acid polyglycidyl esters, polyol polyglycidyl ethers, aliphatic or cycloaliphatic epoxy resins, amine epoxy resins, triphenolmethane type epoxy resins, dihydroxybenzene type epoxy resins and the like (meth) Acry Photopolymerizable compound in epoxy (meth) acrylate obtained by reacting an acid; photopolymerizable liquid crystal compound having an acryl group and a methacryl group; and the like.
The amount of these compounds added to the reactive liquid crystal is selected within a range that does not impair the object of the present invention. Addition of these compounds improves the curability of the reactive liquid crystal, increases the mechanical strength of the resulting reactive liquid crystal layer, and improves its stability.

  Examples of the application method of the coating liquid for forming the reactive liquid crystal layer include spin coating, roll coating, printing, dip coating, die coating, casting, bar coating, blade coating, spray coating, Examples thereof include a gravure coating method, a reverse coating method, an extrusion coating method, an ink jet method, a flexographic printing method, and a screen printing method.

  Moreover, after apply | coating the said coating liquid for reactive liquid crystal layer formation, a solvent is removed. Examples of the method for removing the solvent include removal under reduced pressure or heat removal, and a combination of these.

  After application of the coating liquid for forming the reactive liquid crystal layer, the applied reactive liquid crystal is aligned by the first alignment film so as to have liquid crystal regularity. That is, a nematic phase is developed in the reactive liquid crystal. This is usually performed by a method such as a method of performing a heat treatment at a temperature lower than the temperature at which the nematic phase transitions to the isotropic phase (NI transition point).

  As described above, the reactive liquid crystal contains a polymerizable liquid crystal material, and a method of irradiating active radiation that activates polymerization is used to fix the alignment state of such a polymerizable liquid crystal material. It is done. The active radiation as used herein refers to radiation capable of causing polymerization of the polymerizable liquid crystal material. If necessary, a photopolymerization initiator may be included in the polymerizable liquid crystal material.

  The actinic radiation is not particularly limited as long as it is a radiation capable of polymerizing the polymerizable liquid crystal material, but usually ultraviolet rays or visible light is used from the viewpoint of the ease of the apparatus. Irradiation light having a wavelength of 150 to 500 nm, preferably 250 to 450 nm, and more preferably 300 to 400 nm is used.

  Among them, a method of irradiating ultraviolet rays with active radiation to a polymerizable liquid crystal material in which the photopolymerization initiator generates radicals with ultraviolet rays and the polymerizable liquid crystal material undergoes radical polymerization is preferable. This is because the method using ultraviolet rays as actinic radiation is an already established technique, and therefore it can be easily applied to the present invention including the photopolymerization initiator to be used.

  As the light source of this irradiation light, low pressure mercury lamp (sterilization lamp, fluorescent chemical lamp, black light), high pressure discharge lamp (high pressure mercury lamp, metal halide lamp), short arc discharge lamp (super high pressure mercury lamp, xenon lamp, mercury xenon) Lamp). In particular, the use of metal halide lamps, xenon lamps, high-pressure mercury lamps, etc. is recommended. The irradiation intensity is appropriately adjusted according to the composition of the reactive liquid crystal and the amount of photopolymerization initiator.

  Such irradiation with active radiation may be performed under a temperature condition in which the polymerizable liquid crystal material becomes a liquid crystal phase, or may be performed at a temperature lower than the temperature at which the liquid crystal phase is formed. This is because the alignment state of the polymerizable liquid crystal material once in the liquid crystal phase is not disturbed suddenly even if the temperature is lowered thereafter.

  As a method for fixing the alignment state of the polymerizable liquid crystal material, in addition to the method of irradiating the active radiation, a method of polymerizing the polymerizable liquid crystal material by heating can also be used. As the reactive liquid crystal used in this case, it is preferable that the polymerizable liquid crystal monomer contained in the reactive liquid crystal is thermally polymerized below the NI transition point of the reactive liquid crystal.

  The thickness of the reactive liquid crystal layer is appropriately adjusted according to the target anisotropy, and can be set, for example, within a range of 1 nm to 1000 nm, preferably within a range of 3 nm to 100 nm. is there. This is because if the reactive liquid crystal layer is too thick, anisotropy more than necessary occurs, and if the reactive liquid crystal layer is too thin, the predetermined anisotropy may not be obtained.

(3) Partition / Spacer Formation Step In the liquid crystal side substrate preparation step in the present invention, a partition / spacer formation step of forming a partition or spacer on the first substrate may be performed before the first alignment film formation step. .

As will be described later, when the partition / spacer forming step for forming the partition or spacer on the second substrate is performed, the partition / spacer forming step for forming the partition or spacer on the first substrate is not performed. That is, a partition wall or a spacer may be formed on the liquid crystal side substrate, and a partition wall or a spacer may be formed on the counter substrate.
In particular, when the partition is formed, it is preferable to form the partition on the liquid crystal side substrate. When the ferroelectric liquid crystal flows on the first alignment film in an isotropic phase state by applying the ferroelectric liquid crystal to the liquid crystal side substrate on which the partition walls are formed in the liquid crystal application process described later. This is because the flow distance of the dielectric liquid crystal can be shortened, and alignment disorder can be prevented from occurring at the contact interface of the flowing ferroelectric liquid crystal. Further, by applying the ferroelectric liquid crystal to the liquid crystal side substrate on which the partition walls are formed, it is possible to prevent uneven application, and to suppress the occurrence of uneven alignment due to uneven application.
Hereinafter, the description will be divided into the partition wall forming step and the spacer forming step.

(I) Partition Wall Formation Step The liquid crystal side substrate preparation step in the present invention preferably has a partition wall formation step of forming partition walls on the first base material for the reasons described above.

  As a material for the partition wall, a material generally used for a partition wall of a liquid crystal display element can be used. Specifically, examples of the material for the partition include a resin, and among them, a photosensitive resin is preferably used. This is because the photosensitive resin is easy to pattern. As this photosensitive resin, the photosensitive resin generally used for the partition of a liquid crystal display element can be used.

  The method for forming the partition wall is not particularly limited as long as the partition wall can be formed at a predetermined position, and a general patterning method can be applied. For example, a photolithography method, an inkjet method Method, screen printing method and the like.

  A plurality of partition walls are formed, and it is preferable to form the plurality of partition walls regularly at predetermined positions, and it is particularly preferable to form the partition walls substantially in parallel at equal intervals. This is because if the formation positions of the plurality of partition walls are disordered, it may be difficult to accurately control the application amount of the ferroelectric liquid crystal.

  In addition, the formation position of the partition is not particularly limited, but it is preferable to form the partition in the non-pixel region. This is because the alignment defect of the ferroelectric liquid crystal tends to occur in the vicinity of the partition wall, and it is preferable that the partition wall is formed in a non-pixel region that does not affect image display. For example, when the liquid crystal side substrate is a TFT substrate, partition walls can be arranged on the gate electrode and the source electrode formed in a matrix.

  The plurality of partition walls are formed in a pattern shape. For example, the partition walls may be formed in a stripe shape, a matrix shape, or a frame shape. When the partition walls are formed in a matrix shape, impact resistance can be improved. When the partition walls are formed in a frame shape, as illustrated in FIG. 14, a frame-shaped partition wall 8b is formed on the peripheral edge of the first base material 2, and a sealant is formed on the outer periphery of the frame-shaped partition wall 8b. 6 prevents the ferroelectric liquid crystal 5 and the uncured sealant 6 from coming into contact with each other, and prevents the characteristics of the ferroelectric liquid crystal from deteriorating due to the mixing of impurities or the like in the sealant. be able to. In FIG. 14, a stripe-shaped partition wall 8a is also formed.

  The pitch of the partition walls is about 100 μm to 10 mm, preferably in the range of 200 μm to 1.5 mm, more preferably in the range of 1.0 mm to 5.0 mm. This is because if the partition pitch is narrower than the above range, the display quality may be deteriorated due to poor alignment of the ferroelectric liquid crystal near the partition. On the contrary, if the partition pitch is wider than the above range, it may vary depending on the size of the liquid crystal display element, but the desired impact resistance may not be obtained, or it may be difficult to keep the cell gap constant. Because. In addition, the pitch of a partition means the distance from the center part of an adjacent partition to a center part.

  Moreover, the width | variety of a partition shall be about 1 micrometer-20 micrometers, Preferably it exists in the range of 2 micrometers-10 micrometers, More preferably, it exists in the range of 5 micrometers-10 micrometers. As illustrated in FIG. 14, when the frame-shaped partition wall 8 b is formed on the peripheral portion of the first base material 2, the width of the frame-shaped partition wall is determined by the ferroelectric liquid crystal, the uncured sealant, It is sufficient that the width is such that the contact can be prevented. Specifically, the width is about 10 μm to 3 mm, preferably in the range of 10 μm to 1 mm, more preferably in the range of 10 μm to 500 μm. If the partition wall width is wider than the above range, the partition wall is also provided in the pixel region, the effective pixel area may become narrow, and a good image display may not be obtained, and the partition wall width is more than the above range. This is because if it is narrow, it may be difficult to form a partition wall.

  In addition, the height of the partition walls is usually about the same as the cell gap.

  Note that the pitch, width, and height of the partition walls can be measured by observing a cross section of the partition walls using a scanning electron microscope (SEM).

  The number of partition walls is not particularly limited as long as it is plural, and is appropriately selected depending on the size of the liquid crystal display element.

  The partition forming step may be performed before the first alignment film forming step, and the partition may be formed on the first substrate, or the partition may be formed on the first electrode layer. That is, on the first base material, the partition and the first electrode layer may be formed in this order, or the first electrode layer and the partition may be formed in this order.

(Ii) Spacer formation process The liquid crystal side substrate preparation process in this invention may have the spacer formation process which forms a spacer on the 1st base material.

  As a material of the spacer, a material generally used for a spacer of a liquid crystal display element can be used. Specifically, examples of the material for the spacer include a resin, and among them, a photosensitive resin is preferably used. This is because the photosensitive resin is easy to pattern. As this photosensitive resin, the photosensitive resin generally used for the spacer of a liquid crystal display element can be used.

  The method for forming the spacer is not particularly limited as long as the spacer can be formed at a predetermined position, and a general patterning method can be applied. For example, a photolithography method, an inkjet method Method, screen printing method and the like.

  Further, a plurality of spacers are also formed, and the plurality of spacers are preferably formed regularly at predetermined positions, and particularly preferably formed at equal intervals. This is because if the formation positions of the plurality of spacers are disordered, it may be difficult to accurately control the application amount of the ferroelectric liquid crystal.

  The pitch of the spacers can be about 100 μm to 3 mm, preferably in the range of 200 μm to 1.5 mm, more preferably in the range of 300 μm to 1.0 mm. This is because if the spacer pitch is narrower than the above range, the display quality may be deteriorated due to poor alignment of the ferroelectric liquid crystal near the spacer. On the contrary, if the spacer pitch is wider than the above range, it may vary depending on the size of the liquid crystal display element, but the desired impact resistance may not be obtained, or it may be difficult to keep the cell gap constant. Because. The spacer pitch refers to the distance from the center to the center of adjacent spacers.

  As the size of the spacer, for example, when the spacer has a cylindrical shape, the diameter of the bottom surface is about 1 μm to 100 μm, preferably in the range of 2 μm to 50 μm, more preferably in the range of 5 μm to 20 μm. If the size of the spacer is larger than the above range, the spacer is also provided in the pixel region, the effective pixel area becomes narrow, and a good image display may not be obtained. If it is smaller than the range, it may be difficult to form the spacer.

  In addition, the height of the spacer is usually the same as the cell gap.

  Note that the pitch, size, and height of the spacer can be measured by observing the cross section of the partition wall using a scanning electron microscope (SEM).

  Examples of the shape of the spacer include a cylindrical shape, a prismatic shape, and a truncated cone shape.

  Further, the position where the spacer is formed is not particularly limited, but it is preferable that the spacer is formed in the non-pixel region. This is because the alignment defect of the ferroelectric liquid crystal tends to occur near the spacer, and therefore it is preferable that the spacer is formed in a non-pixel region that does not affect image display. For example, when the liquid crystal side substrate is a TFT substrate, spacers can be disposed on the gate electrode and the source electrode formed in a matrix.

  The number of spacers is not particularly limited as long as it is plural, and is appropriately selected depending on the size of the liquid crystal display element.

  The spacer forming step may be performed before the first alignment film forming step, and the spacer may be formed on the first base material, or the spacer may be formed on the first electrode layer. That is, the spacer and the first electrode layer may be formed in this order on the first substrate, or the first electrode layer and the spacer may be formed in this order.

(4) Colored layer formation process In the liquid crystal side substrate preparation process in this invention, you may perform the colored layer formation process which forms a colored layer on a 1st base material before a 1st alignment film formation process. As will be described later, when the colored layer forming step for forming the colored layer on the second substrate is performed, the colored layer forming step for forming the colored layer on the first substrate is not performed. That is, a colored layer may be formed on the liquid crystal side substrate, or a colored layer may be formed on the counter substrate.
When the colored layer is formed, a color filter type liquid crystal display element capable of realizing color display by the colored layer can be obtained.

  As a method for forming the colored layer, a method for forming a colored layer in a general color filter can be used. For example, a pigment dispersion method (color resist method, etching method), a printing method, an inkjet method, or the like can be used. it can.

3. Counter substrate preparation process In this invention, you may perform the counter substrate preparation process which prepares the counter substrate in which the 2nd electrode layer was formed on the 2nd base material. The counter substrate preparation step preferably includes a second alignment film forming step of forming a second alignment film on the second base material on which the second electrode layer is formed. In the method for manufacturing a liquid crystal display element of the present invention, the second alignment film is considered not to contribute to the control of the direction of spontaneous polarization of the ferroelectric liquid crystal, but is strong between the first alignment film and the second electrode layer. This is because the orientation of the ferroelectric liquid crystal is stabilized when the ferroelectric liquid crystal is sandwiched between the first alignment film and the second alignment film as compared with the case where the dielectric liquid crystal is sandwiched.

In the counter substrate preparation step, a partition wall / spacer forming step for forming a partition wall or a spacer on the second base material may be performed before the second alignment film forming step, and a colored layer is formed on the second base material. You may perform the colored layer formation process which forms. The partition / spacer forming step and the colored layer forming step are the same as the partition / spacer forming step and the colored layer forming step described in the liquid crystal side substrate preparing step, respectively, and thus the description thereof is omitted here.
Hereinafter, the second alignment film forming step will be described.

(1) Second alignment film forming step The second alignment film forming step in the present invention is a step of forming the second alignment film on the second substrate on which the second electrode layer is formed.

  The method for forming the second alignment film is not particularly limited as long as the second alignment film capable of aligning the ferroelectric liquid crystal is obtained. For example, a second alignment film can be formed by forming a film on the second electrode layer and subjecting this film to a rubbing process, a photo-alignment process, or the like. Among these, it is preferable to form the second alignment film by photo-alignment treatment. This is because the photo-alignment process is a non-contact alignment process and is useful in that there is no generation of static electricity or dust and quantitative control of the alignment process is possible.

  Note that the method for forming the second alignment film by the photo-alignment process is the same as the method for forming the first alignment film by the photo-alignment process, and a description thereof will be omitted here.

  A combination of materials used for the first alignment film and the second alignment film is not particularly limited, but the materials used for the first alignment film and the second alignment film preferably have different compositions from each other. . By forming the first alignment film and the second alignment film using materials having different compositions, the polarities of the first alignment film surface and the second alignment film surface can be made different depending on the respective materials. As a result, the polar surface interaction between the ferroelectric liquid crystal and the first alignment film and the polar surface interaction between the ferroelectric liquid crystal and the second alignment film are different, so that the first alignment film and the second alignment film By appropriately selecting the material in consideration of the surface polarity of the alignment film, the spontaneous polarization of the ferroelectric liquid crystal can be effectively directed toward the second alignment film.

  In order to effectively direct the spontaneous polarization of the ferroelectric liquid crystal toward the second alignment film, the first alignment film has a positive polarity larger than that of the second alignment film. It is preferable to select materials used for the alignment film and the second alignment film. On the other hand, in the present invention, since the spontaneous polarization of the ferroelectric liquid crystal is directed to the opposite side of the first alignment film coated with the ferroelectric liquid crystal, that is, the second alignment film side, the second alignment film is the first one. Even when the positive polarity is relatively larger than that of the alignment film, the spontaneous polarization of the ferroelectric liquid crystal can be directed to the second alignment film side.

  The polar surface interaction, which is the interaction between the ferroelectric liquid crystal and the first alignment film surface and the second alignment film surface, is evaluated by examining the change in the direction of spontaneous polarization of the ferroelectric liquid crystal with respect to the applied voltage. Can do.

First, a liquid crystal display element to be evaluated in which a ferroelectric liquid crystal is sandwiched between a first alignment film and a second alignment film is manufactured by a vacuum injection method.
Next, a change in the direction of spontaneous polarization of the ferroelectric liquid crystal with respect to the applied voltage is examined using the liquid crystal display element to be evaluated.
For example, as shown in FIG. 15A, when the second alignment film 14 has a relatively positive polarity relative to the first alignment film 4, the liquid crystal molecules 15 have a molecular positive electrode when no voltage is applied. Arrangement is made so as to face the first alignment film 4 side, and the spontaneous polarization Ps faces the first alignment film 4 side. In this case, even if a voltage is applied so that the first electrode layer 3 is the negative electrode and the second electrode layer 13 is the positive electrode, the direction of the spontaneous polarization Ps does not change, but the first electrode layer 3 is the positive electrode and the second electrode. When a voltage is applied so that the layer 13 becomes a negative electrode, the direction of the spontaneous polarization Ps is reversed.
On the other hand, as shown in FIG. 15B, when the first alignment film 4 has a relatively positive polarity larger than that of the second alignment film 14, the liquid crystal molecules 15 have a molecular positive electrode when no voltage is applied. They are arranged so as to face the second alignment film 14 side, and the spontaneous polarization Ps faces the second alignment film 14 side. In this case, even if a voltage is applied so that the first electrode layer 3 is the positive electrode and the second electrode layer 13 is the negative electrode, the direction of the spontaneous polarization Ps does not change, but the first electrode layer 3 is the negative electrode and the second electrode. When a voltage is applied so that the layer 13 becomes a positive electrode, the direction of the spontaneous polarization Ps is reversed.
The direction of spontaneous polarization is such a direction because the direction of spontaneous polarization is the direction in which the polarization of the ferroelectric liquid crystal and the polarization of the alignment film or the polarity of the voltage are electrically balanced. This is because the state becomes stable.

  Therefore, when the voltage is applied so that the first electrode layer is a positive electrode and the second electrode layer is a negative electrode, the direction of the spontaneous polarization is reversed. The second alignment film is more relative to the first alignment film. It can be said that positive polarity is large. On the other hand, when the voltage is applied so that the first electrode layer is the negative electrode and the second electrode layer is the positive electrode, the direction of the spontaneous polarization is reversed. It can be said that positive polarity is large.

  However, not all ferroelectric liquid crystals reverse the direction of spontaneous polarization when a predetermined voltage is applied. Therefore, after placing the liquid crystal display element to be evaluated between two polarizing plates arranged in crossed Nicols and applying a voltage to the dark state, the first electrode layer is the positive electrode, the second electrode layer is the negative electrode, By applying a voltage so that the ferroelectric liquid crystal rotates on the cone and 51% or more of the display area of the liquid crystal display element to be evaluated is in a bright state, the second alignment film is more Assume that the positive polarity is relatively larger than that of one alignment film. In addition, the liquid crystal display element to be evaluated is placed between two polarizing plates arranged in a crossed Nicol state and darkened without applying voltage, and in this state, the first electrode layer is a negative electrode, and the second electrode layer is a positive electrode. When the ferroelectric liquid crystal rotates on the cone by applying a voltage so that 51% or more of the display area of the liquid crystal display element to be evaluated is in a bright state, the first alignment film is more Assume that the positive polarity is relatively larger than that of the bi-alignment film.

  In addition, when a predetermined voltage is applied, 51% or more of the display area of the liquid crystal display element to be evaluated becomes bright. For example, the display state of the liquid crystal display element to be evaluated at the time of voltage application is observed with a polarizing microscope. This can be confirmed by obtaining the white / black area of black and white (bright / dark) display and calculating the ratio of the bright state.

  In order to make the compositions of the materials used for the first alignment film and the second alignment film different, for example, a photo-alignment material is used for one and a rubbing alignment material is used for the other, or the first alignment film and the second alignment film are used. Rubbing alignment materials having different compositions may be used for the film, or photoalignment materials having different compositions may be used for the first alignment film and the second alignment film. Further, when using photoalignable materials having different compositions for the first alignment film and the second alignment film, for example, a photoisomerizable material is used for one and a photoreactive material is used for the other, or the first alignment is used. Photoisomerizable materials having different compositions may be used for the film and the second alignment film, or photoreactive materials having different compositions may be used for the first alignment film and the second alignment film.

When photoisomerizable materials having different compositions are used for the first alignment film and the second alignment film, cis-trans isomerization reactivity is selected from the above-described photoisomerization reactive compounds according to required characteristics. By selecting various skeletons and substituents, the composition of the photoisomerizable material can be made different. Moreover, a composition can also be changed by changing the addition amount of the additive mentioned above.
Further, in the case of using photoreactive materials having different compositions for the first alignment film and the second alignment film, and using a photodimerization material as the photoreaction material, the photodimerization reactive compound described above, For example, the composition of the photodimerization type material can be made different by selecting various photodimerization reactive polymers. Furthermore, the composition can be changed by changing the amount of the additive described above.

  In particular, in order to effectively direct the spontaneous polarization of the ferroelectric liquid crystal toward the second alignment film, it is preferable to form a reactive liquid crystal layer on the first alignment film. This is because when the polar surface interaction is evaluated as described above, the reactive liquid crystal layer tends to have a relatively higher positive polarity than the alignment film using the photo-alignment material or the rubbing alignment material.

  Furthermore, it is preferable that reactive liquid crystal is formed on the first alignment film, and the second alignment film is a photo-alignment film using a photodimerization type material or a photoisomerization type material. When the polar surface interaction is evaluated as described above, it is considered that the relative polarity difference is relatively large between the reactive liquid crystal layer and the photo-alignment film using the photodimerization type material or the photoisomerization type material. Because.

4). Liquid crystal coating process In the liquid crystal coating process of the present invention, a ferroelectric liquid crystal is coated on the first alignment film of the liquid crystal side substrate in which the first electrode layer and the first alignment film are laminated in this order on the first base material. It is a process to do.

  When applying the ferroelectric liquid crystal on the first alignment film of the liquid crystal side substrate, the ferroelectric liquid crystal may or may not be heated. The temperature of the ferroelectric liquid crystal is appropriately selected according to the ferroelectric liquid crystal coating method described later.

  For example, when a discharge method is used as a coating method of the ferroelectric liquid crystal, it is preferable that the ferroelectric liquid crystal is heated to a temperature at which the ferroelectric liquid crystal exhibits an isotropic phase or a nematic phase, and particularly the ferroelectric property. It is preferable that the liquid crystal is heated to a temperature exhibiting an isotropic phase. This is because if the ferroelectric liquid crystal is not heated, the viscosity of the ferroelectric liquid crystal is too high and the discharge nozzle is clogged, making it very difficult to stably discharge the ferroelectric liquid crystal.

  In the above case, the temperature of the ferroelectric liquid crystal is set to a temperature at which the ferroelectric liquid crystal exhibits an isotropic phase or a nematic phase. The specific temperature differs depending on the type of ferroelectric liquid crystal and is appropriately selected. Note that the upper limit of the temperature of the ferroelectric liquid crystal is a temperature at which the ferroelectric liquid crystal does not deteriorate. Usually, the temperature of the ferroelectric liquid crystal is set in the vicinity of the nematic phase-isotropic phase transition temperature, or is set to 0 ° C. to 10 ° C. higher than the nematic phase-isotropic phase transition temperature.

  In addition, when a discharge method is used as a coating method of the ferroelectric liquid crystal, the ferroelectric liquid crystal is heated so that the viscosity of the ferroelectric liquid crystal is 30 mPa · s or less, particularly in the range of 10 mPa · s to 20 mPa · s. It is preferable to do. This is because if the viscosity of the ferroelectric liquid crystal is too high, the discharge nozzle becomes clogged and it becomes very difficult to stably discharge the ferroelectric liquid crystal.

  On the other hand, when a coating method or a printing method is used as a method for applying the ferroelectric liquid crystal, it is preferable that the ferroelectric liquid crystal is not heated. When using a coating method or a printing method, it is preferable to use a ferroelectric liquid crystal solution obtained by diluting a ferroelectric liquid crystal with a solvent in order to improve the coating property. For this reason, when the ferroelectric liquid crystal solution is heated, the solvent in the ferroelectric liquid crystal solution is volatilized and it becomes very difficult to apply the ferroelectric liquid crystal.

  Further, when applying the ferroelectric liquid crystal on the first alignment film of the liquid crystal side substrate, the liquid crystal side substrate may or may not be heated. The temperature of the liquid crystal side substrate is appropriately selected depending on the application method of the ferroelectric liquid crystal.

For example, when a discharge method is used as a ferroelectric liquid crystal application method, the liquid crystal side substrate may or may not be heated. Among these, it is preferable not to heat the liquid crystal side substrate. That is, it is preferable to set the temperature of the liquid crystal side substrate to room temperature. This is because the deterioration of the ferroelectric liquid crystal in the liquid crystal application process can be suppressed by not heating the liquid crystal side substrate. Further, it is not necessary to heat the liquid crystal side substrate, so that the cost can be reduced.
In addition, room temperature means about 15 degreeC-30 degreeC.

  When the liquid crystal side substrate is heated, the temperature of the liquid crystal side substrate is preferably set to a temperature at which the ferroelectric liquid crystal exhibits an isotropic phase or a nematic phase, and in particular, the ferroelectric liquid crystal has an isotropic phase. It is preferable to set to the temperature shown. The specific temperature differs depending on the type of ferroelectric liquid crystal and is appropriately selected. The upper limit of the temperature of the liquid crystal side substrate is a temperature at which the ferroelectric liquid crystal does not deteriorate. Usually, the temperature of the liquid crystal side substrate is set in the vicinity of the nematic phase-isotropic phase transition temperature, or is set 5 ° C. to 10 ° C. higher than the nematic phase-isotropic phase transition temperature.

  On the other hand, when a coating method or a printing method is used as a method for applying the ferroelectric liquid crystal, it is preferable not to heat the liquid crystal side substrate. This is because when the liquid crystal side substrate is heated, the solvent in the applied ferroelectric liquid crystal solution volatilizes, and the orientation of the ferroelectric liquid crystal may be disturbed.

  The method for applying the ferroelectric liquid crystal is not particularly limited as long as it can apply a predetermined amount capable of enclosing the ferroelectric liquid crystal on the first alignment film or the reactive liquid crystal layer. In particular, it is preferable that the ferroelectric liquid crystal can be applied so that the ferroelectric liquid crystal hardly flows. If the flow distance of the ferroelectric liquid crystal is too long when the ferroelectric liquid crystal flows in an isotropic phase on the first alignment film, the alignment may be disturbed at the interface where the flowed ferroelectric liquid crystal contacts. Because there is.

  Examples of such a coating method include a discharge method such as an ink jet method and a dispenser method, a coating method such as a bar coating method and a slot die coating method, a printing method such as a flexographic printing method, a gravure printing method, an offset printing method, and a screen printing method. Law. Of these, the discharge method is preferable, and the inkjet method is particularly preferable. If the inkjet method is used, the ferroelectric liquid crystal can be applied in a continuous manner, so that the ferroelectric liquid crystal can be applied so as to shorten the flow distance, and at the contact interface of the flowed ferroelectric liquid crystal. This is because the occurrence of alignment disorder can be prevented.

5. Substrate bonding step The substrate bonding step in the present invention is a step of bonding a liquid crystal side substrate coated with a ferroelectric liquid crystal and a counter substrate having a second electrode layer formed on a second base material.

  Before the liquid crystal side substrate and the counter substrate are bonded together, a sealant is applied to the peripheral portion of at least one of the liquid crystal side substrate and the counter substrate. As illustrated in FIG. 2, the sealing agent 6 is normally applied in a frame shape so as to surround the outer periphery of the region where the ferroelectric liquid crystal 5 is applied. Further, as illustrated in FIG. 14, when a frame-shaped partition wall 8 b is provided on the liquid crystal side substrate or the counter substrate, the sealing agent 6 is applied so as to surround the outer periphery of the frame-shaped partition wall 8 b.

  Moreover, when apply | coating a sealing agent to a liquid crystal side board | substrate, a sealing agent may be apply | coated on a 1st base material and you may apply | coat on a 1st orientation film. When a sealing agent is applied on the first base material, the adhesion between the liquid crystal side substrate and the counter substrate can be improved. When applying the sealing agent on the first substrate, the first alignment film is formed in a pattern so that the first alignment film is not formed on the peripheral edge of the first substrate. On the other hand, also when apply | coating a sealing agent to a counter substrate, a sealing agent may be apply | coated on a 2nd base material and you may apply | coat on a 2nd alignment film.

  The sealing agent may be applied to the substrate on which the partition wall or spacer is formed in relation to the partition wall or spacer, or may be applied to the substrate on which the partition wall or spacer is not formed, or applied to both substrates. Also good. Further, the sealing agent may be applied to a liquid crystal side substrate coated with a ferroelectric liquid crystal or a counter substrate not coated with a ferroelectric liquid crystal in relation to the ferroelectric liquid crystal. , May be applied to both substrates. In any case, when the liquid crystal side substrate and the counter substrate are overlapped, the sealing agent is applied so that the outer periphery of the region where the ferroelectric liquid crystal is applied is surrounded by the sealing agent.

  In addition, when applying the sealing agent to the liquid crystal side substrate, the sealing agent may be applied before applying the ferroelectric liquid crystal to the liquid crystal side substrate, or after applying the ferroelectric liquid crystal to the liquid crystal side substrate. It may be applied.

  As the sealing agent, sealing agents generally used for liquid crystal display elements can be used, and examples thereof include thermosetting resins and ultraviolet curable resins.

  The method for applying the sealing agent is not particularly limited as long as it can apply the sealing agent at a predetermined position, and examples thereof include a dispenser method and a screen printing method.

  After applying the sealant in this way, the liquid crystal side substrate and the counter substrate are overlaid. When the liquid crystal side substrate and the counter substrate are overlaid, the liquid crystal side substrate and the counter substrate are opposed so that the alignment processing directions of the first alignment film and the second alignment film are substantially parallel.

  In addition, when the liquid crystal side substrate and the counter substrate are overlaid, the liquid crystal side substrate and the counter substrate are heated. The temperature of the liquid crystal side substrate and the counter substrate is preferably set to a temperature at which the ferroelectric liquid crystal exhibits an isotropic phase or a nematic phase. Among them, the temperature at which the ferroelectric liquid crystal exhibits an isotropic phase is preferably set. preferable. The specific temperature differs depending on the type of ferroelectric liquid crystal and is appropriately selected. The upper limit of the temperature of the liquid crystal side substrate and the counter substrate is set to a temperature at which the ferroelectric liquid crystal does not deteriorate. Usually, the temperature of the liquid crystal side substrate and the counter substrate is set in the vicinity of the nematic phase-isotropic phase transition temperature, or is set 5 ° C. to 10 ° C. higher than the nematic phase-isotropic phase transition temperature.

  In addition, it is preferable to heat the liquid crystal side substrate and the counter substrate so that the viscosity of the ferroelectric liquid crystal is 30 mPa · s or less, particularly in the range of 10 mPa · s to 20 mPa · s. This is because if the viscosity of the ferroelectric liquid crystal is too high, the ferroelectric liquid crystal hardly flows on the first alignment film.

  When a ferroelectric liquid crystal solution obtained by diluting a ferroelectric liquid crystal with a solvent is applied on the first alignment film by a printing method, the solvent can be removed when the liquid crystal side substrate is heated.

Further, when the liquid crystal side substrate and the counter substrate are overlaid, it is preferable that the chamber is evacuated to sufficiently reduce the pressure between the liquid crystal side substrate and the counter substrate. Thereby, it can prevent that a space | gap remains in a liquid crystal cell.
After the liquid crystal side substrate and the counter substrate are opposed to each other in this way, the liquid crystal side substrate and the counter substrate are superposed under reduced pressure, and a certain pressure is applied so that the cell gap becomes uniform. Then, by returning the inside of the chamber to normal pressure, further pressure is applied between the liquid crystal side substrate and the counter substrate. Thereby, a cell gap can be made more uniform. In this way, the liquid crystal side substrate and the counter substrate are pressure-bonded via the sealant.

After the liquid crystal side substrate and the counter substrate are overlaid, the sealant is cured and the liquid crystal side substrate and the counter substrate are bonded.
The curing method of the sealing agent varies depending on the type of the sealing agent used, and examples thereof include a method of irradiating with ultraviolet rays and a method of heating. At this time, normally, the sealing agent is cured while maintaining the pressure when the liquid crystal side substrate and the counter substrate are overlapped.

After the liquid crystal side substrate and the counter substrate are bonded together, the ferroelectric liquid crystal sealed between the liquid crystal side substrate and the counter substrate is aligned. Specifically, the ferroelectric liquid crystal is in a chiral smectic C (SmC ^* ) phase state. As described above, the liquid crystal side substrate and the counter substrate are heated to a predetermined temperature, whereby the ferroelectric liquid crystal is heated to be in a nematic phase or isotropic phase, for example. Can be brought into the SmC ^* phase state.

  When cooling the heated ferroelectric liquid crystal, the ferroelectric liquid crystal is usually gradually cooled to room temperature.

  When a polymerizable monomer is added to the ferroelectric liquid crystal, the polymerizable monomer is polymerized after aligning the ferroelectric liquid crystal. The polymerization method of the polymerizable monomer is appropriately selected according to the type of the polymerizable monomer. For example, when an ultraviolet curable resin monomer is used as the polymerizable monomer, the polymerizable monomer can be polymerized by ultraviolet irradiation. .

  Further, when polymerizing the polymerizable monomer, a voltage may or may not be applied to the liquid crystal layer composed of the ferroelectric liquid crystal, but no voltage is applied to the liquid crystal layer. It is preferable to polymerize a polymerizable monomer.

  The thickness of the liquid crystal layer composed of ferroelectric liquid crystal is preferably in the range of 1.2 μm to 3.0 μm, more preferably 1.3 μm to 2.5 μm, and even more preferably 1.4 μm to 2 μm. Within the range of 0.0 μm. This is because if the thickness of the liquid crystal layer is too thin, the contrast may be lowered. Conversely, if the thickness of the liquid crystal layer is too thick, the ferroelectric liquid crystal may be difficult to align.

6). Driving method of liquid crystal display element As a driving method of the liquid crystal display element obtained by the present invention, since the high-speed response of the ferroelectric liquid crystal can be used, one pixel is divided into time to obtain good moving image display characteristics. Therefore, a field sequential color system that requires high-speed response is suitable. According to the present invention, as described above, it is possible to avoid problems caused when driven by the field sequential color system.

  The driving method of the liquid crystal display element is not limited to the field sequential method, and may be a color filter method that performs color display using a colored layer.

  Furthermore, as a driving method of the liquid crystal display element, an active matrix system using a thin film transistor (TFT) is preferable. This is because by adopting an active matrix system using TFTs, the target pixel can be reliably turned on and off, and a high-quality display becomes possible.

  FIG. 16 shows an example of an active matrix liquid crystal display element using TFTs. The liquid crystal display element illustrated in FIG. 16 includes a TFT substrate (liquid crystal side substrate) 1 in which a TFT element 21 is disposed on a first base 2 and a common electrode (second electrode layer) 13 on a second base 12. And a common electrode substrate (counter substrate) 11 on which the second alignment film 14 is formed. On the TFT substrate (liquid crystal side substrate) 1, a gate electrode 22x, a source electrode 22y, and a pixel electrode (first electrode layer) 3 are formed. The gate electrode 22x and the source electrode 22y are arranged vertically and horizontally, respectively, and the TFT element 21 can be operated by applying a signal to the gate electrode 22x and the source electrode 22y to drive the ferroelectric liquid crystal. A portion where the gate electrode 22x and the source electrode 22y intersect is insulated by an insulating layer (not shown), and the signal of the gate electrode 22x and the signal of the source electrode 22y can operate independently. A portion surrounded by the gate electrode 22x and the source electrode 22y is a pixel which is a minimum unit for driving the liquid crystal display element. Each pixel includes at least one TFT element 21 and a pixel electrode (first electrode layer) 3. Is formed. Then, by sequentially applying a signal voltage to the gate electrode and the source electrode, the TFT element of each pixel can be operated. In FIG. 16, the liquid crystal layer and the first alignment film are omitted.

  In the above example, the liquid crystal side substrate is a TFT substrate and the counter substrate is a common electrode substrate. However, the present invention is not limited to this, and the liquid crystal side substrate is a common electrode substrate and the counter substrate is a TFT substrate. There may be.

Among these, it is preferable that the liquid crystal side substrate is a common electrode substrate and the counter substrate is a TFT substrate.
FIG. 17 shows another example of an active matrix liquid crystal display element using TFTs. The liquid crystal display element illustrated in FIG. 17 includes a common electrode substrate (liquid crystal side substrate) in which a common electrode (first electrode layer) 3, a first alignment film 4 and a reactive liquid crystal layer 4 ′ are formed on a first base material 2. ) 1 and a TFT substrate (counter substrate) 11 in which the TFT element 21 is disposed on the second substrate 12. On the TFT substrate (counter substrate) 11, a gate electrode 22x, a source electrode 22y, and a pixel electrode (second electrode layer) 13 are formed. The gate electrode 22x and the source electrode 22y are arranged vertically and horizontally, respectively, and the TFT element 21 can be operated by applying a signal to the gate electrode 22x and the source electrode 22y to drive the ferroelectric liquid crystal. A portion where the gate electrode 22x and the source electrode 22y intersect is insulated by an insulating layer (not shown), and the signal of the gate electrode 22x and the signal of the source electrode 22y can operate independently. A portion surrounded by the gate electrode 22x and the source electrode 22y is a pixel which is a minimum unit for driving the liquid crystal display element. Each pixel includes at least one TFT element 21 and a pixel electrode (second electrode layer) 13. Is formed. Then, by sequentially applying a signal voltage to the gate electrode and the source electrode, the TFT element of each pixel can be operated. In FIG. 17, the liquid crystal layer and the second alignment film are omitted.

In the liquid crystal display element illustrated in FIG. 17, for example, when the gate electrode is set to a high potential of about 30 V, the TFT element is switched on, the signal voltage is applied to the ferroelectric liquid crystal by the source electrode, and the gate electrode is set to −10 V. When the potential is low, the TFT element is turned off. In the switch-off state, as illustrated in FIG. 18, a voltage is applied between the common electrode (first electrode layer) 3 and the gate electrode 22x so that the common electrode (first electrode layer) 3 side is positive. . Since the ferroelectric liquid crystal does not operate in this switch-off state, the pixel is in a dark state.
In the present invention, as described above, when no voltage is applied, the spontaneous polarization of the liquid crystal molecules is directed toward the counter substrate due to the polar surface interaction. That is, in the switch-off state, as illustrated in FIG. 18, the spontaneous polarization Ps of the liquid crystal molecules 15 faces the TFT substrate (counter substrate) 11 side. Therefore, the direction of spontaneous polarization is not affected by the voltage applied between the common electrode (first electrode layer) 3 and the gate electrode 22x.
On the other hand, for example, when the spontaneous polarization is directed to the common electrode substrate (liquid crystal side substrate) when no voltage is applied, the gate electrode is affected by the voltage applied between the common electrode and the gate electrode in the switch-off state. The direction of spontaneous polarization is reversed in the vicinity of the region where is provided. Then, in the vicinity of the region where the gate electrode is provided, the ferroelectric liquid crystal operates and light leakage occurs even though the switch is off.
On the other hand, as described above, in the present invention, the direction of spontaneous polarization is not affected by the voltage applied between the common electrode and the gate electrode, so that no light leakage occurs. Therefore, by controlling the direction of spontaneous polarization and using the liquid crystal side substrate coated with the ferroelectric liquid crystal as the common electrode substrate, light leakage near the gate electrode can be prevented.

  If the pixel electrode voltage is relatively high with respect to the common electrode, a positive polarity voltage application is assumed, and if the pixel electrode voltage is relatively low, a negative polarity voltage application is assumed. In this definition, when the liquid crystal side substrate is a TFT substrate, the ferroelectric liquid crystal has a relatively low voltage of the pixel electrode with respect to the common electrode, that is, when a negative polarity voltage is applied. The molecular direction of the ferroelectric liquid crystal changes approximately twice the tilt angle of the ferroelectric liquid crystal in parallel with the liquid crystal side substrate. In addition, when the liquid crystal side substrate is a common electrode substrate, the ferroelectric liquid crystal has a ferroelectric property when the voltage of the pixel electrode is relatively high with respect to the common electrode, that is, when a positive polarity voltage is applied. The molecular direction of the liquid crystal changes approximately twice the tilt angle of the ferroelectric liquid crystal in parallel with the liquid crystal side substrate.

  The driving method of the liquid crystal display element may be a segment method.

B. Liquid crystal display element The liquid crystal display element of the present invention includes a first substrate, a first electrode layer and a partition formed on the first substrate, and a first formed on the first electrode layer and the partition. A liquid crystal side substrate having an alignment film and a reactive liquid crystal layer formed on the first alignment film and immobilizing reactive liquid crystals, a second substrate, and a second substrate formed on the second substrate. Reaction of counter substrate having two electrode layer and second alignment film which is formed on the second electrode layer and is a photo-alignment film containing a photodimerization type material or a photoisomerization type material, and the liquid crystal side substrate A liquid crystal layer including a ferroelectric liquid crystal formed between the conductive liquid crystal layer and the second alignment film of the counter substrate, wherein the ferroelectric liquid crystal exhibits monostability and the first electrode When a voltage is applied so that the layer is a negative electrode, the molecular direction of the ferroelectric liquid crystal is relative to the liquid crystal side substrate surface. In parallel, the ferroelectric liquid crystal changes about twice the tilt angle of the ferroelectric liquid crystal.

  In addition, “showing monostability” and “when the voltage is applied so that the first electrode layer is a negative electrode, the molecular direction of the ferroelectric liquid crystal is in parallel with the liquid crystal side substrate surface. “It changes about twice the tilt angle of the liquid crystal” is the same as described in “A. Manufacturing method of liquid crystal display element”.

The liquid crystal display element of the present invention will be described with reference to the drawings. FIG. 19 is a schematic cross-sectional view showing an example of the liquid crystal display element of the present invention.
As illustrated in FIG. 19, the liquid crystal display element includes a first base 2, a first electrode layer 3 formed on the first base 2, and a partition formed on the first electrode layer 3. 8, a liquid crystal side substrate 1 having a first alignment film 4 formed on the first electrode layer 3 and the partition wall 8, and a reactive liquid crystal layer 4 ′ formed on the first alignment film 4, and A counter substrate 11 having a second substrate 12, a second electrode layer 13 formed on the second substrate 12, and a second alignment film 14 formed on the second electrode layer 13. doing. A ferroelectric liquid crystal is sandwiched between the liquid crystal side substrate 1 and the counter substrate 11 to form a liquid crystal layer 5 ′. The second alignment film 14 of the counter substrate 11 is a photo-alignment film containing a photodimerization type material or a photoisomerization type material. Further, the ferroelectric liquid crystal in the liquid crystal layer 5 exhibits monostability, and when a voltage is applied so that the first electrode layer 3 of the liquid crystal side substrate 1 becomes a negative electrode, the molecules of the ferroelectric liquid crystal are displayed. The direction is parallel to the surface of the liquid crystal side substrate 11 and changes about twice the tilt angle of the ferroelectric liquid crystal.

In the present invention, the partition is formed on the liquid crystal side substrate. When producing such a liquid crystal display element of the present invention, the ferroelectric liquid crystal is usually applied to the liquid crystal side substrate on which the partition walls are formed because the alignment between the liquid crystal side substrate and the counter substrate is easy. Is applied.
As described above in “A. Manufacturing method of liquid crystal display element”, the spontaneous polarization of the ferroelectric liquid crystal tends to be directed to the counter substrate side on which the ferroelectric liquid crystal is not applied. In the present invention, this can be used to control the direction of spontaneous polarization of liquid crystal molecules.
Further, since the reactive liquid crystal layer is formed on the first alignment film in the liquid crystal side substrate and the second alignment film is a predetermined photo-alignment film in the counter substrate, the above-mentioned “A. Manufacturing method of liquid crystal display element”. As described in the above, the direction of spontaneous polarization of the ferroelectric liquid crystal can be effectively directed to the counter substrate side (photo-alignment film side).
Accordingly, in the present invention, the partition is formed on the liquid crystal side substrate, the reactive liquid crystal layer is formed on the first alignment film, and the second alignment film is the predetermined photo-alignment film on the counter substrate. As a result, the direction of spontaneous polarization of the liquid crystal molecules can be controlled, and the alignment of the ferroelectric liquid crystal can be mono-stabilized without causing alignment defects.

  In addition, about each structure of the liquid crystal display element, since it described in the said "A. manufacturing method of a liquid crystal display element", description here is abbreviate | omitted.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

(Preparation of substrate 1 for liquid crystal display element)
The glass substrate on which the ITO electrode was formed was washed thoroughly, a transparent resist (trade name: NN780, manufactured by JSR) was spin coated on the glass substrate, dried under reduced pressure, and prebaked at 90 ° C. for 3 minutes. Subsequently, it exposed to a mask with 100 mJ / cm ² ultraviolet rays, developed with an inorganic alkali solution, and post-baked at 230 ° C. for 30 minutes. Thereby, a columnar spacer having a height of 1.5 μm was formed.
Next, a 2% by mass cyclopentanone solution of a photodimerization reaction type photo-alignment film material (trade name: ROP-102, manufactured by Rorlic Technology Co., Ltd.) is spin-coated on the substrate on which the columnar spacers are formed, and 130 ° C. And dried for 10 minutes, and then irradiated with about 100 mJ / cm ^{2 of} linearly polarized ultraviolet rays for alignment treatment.

(Preparation of substrate 2 for liquid crystal display element)
The glass substrate on which the ITO electrode is formed is thoroughly washed, and a 2% by mass cyclopentanone solution of a photodimerization reaction type photo-alignment film material (trade name: ROP-102, manufactured by Roric Technology) is applied on the glass substrate. After spin-coating and drying at 130 ° C. for 10 minutes, alignment treatment was performed by irradiating with linear ultraviolet polarized light of about 100 mJ / cm ² .

(Preparation of substrate 3 for liquid crystal display element)
The glass substrate on which the ITO electrode was formed was washed thoroughly, a transparent resist (trade name: NN780, manufactured by JSR) was spin coated on the glass substrate, dried under reduced pressure, and prebaked at 90 ° C. for 3 minutes. Subsequently, it exposed to a mask with 100 mJ / cm ² ultraviolet rays, developed with an inorganic alkali solution, and post-baked at 230 ° C. for 30 minutes. Thereby, a columnar spacer having a height of 1.5 μm was formed.
Next, a 2% by mass cyclopentanone solution of a photodimerization reaction type photo-alignment film material (trade name: ROP-103, manufactured by Rorlic Technology Co., Ltd.) is spin-coated on the substrate on which the columnar spacers are formed, and the temperature is 130 ° C. And dried for 10 minutes, and then irradiated with about 100 mJ / cm ^{2 of} linearly polarized ultraviolet rays for alignment treatment. Further, a 2% by mass cyclopentanone solution of polymerizable liquid crystal (trade name: ROF-5101, manufactured by Roric Technology) was spin-coated and dried at 55 ° C. for 3 minutes, and then non-polarized ultraviolet rays were applied at 55 ° C. And 1000 mJ / cm ² exposure.

(Preparation of substrate 4 for liquid crystal display element)
The glass substrate on which the ITO electrode was formed was washed thoroughly, a transparent resist (trade name: NN780, manufactured by JSR) was spin coated on the glass substrate, dried under reduced pressure, and prebaked at 90 ° C. for 3 minutes. Subsequently, it exposed to a mask with 100 mJ / cm ² ultraviolet rays, developed with an inorganic alkali solution, and post-baked at 230 ° C. for 30 minutes. Thereby, a columnar spacer having a height of 1.5 μm was formed.
Next, a 2% by mass cyclopentanone solution of a photodimerization reaction type photo-alignment film material (trade name: ROP-103, manufactured by Rorlic Technology Co., Ltd.) is spin-coated on the substrate on which the columnar spacers are formed, and the temperature is 130 ° C. And dried for 10 minutes, and then irradiated with about 100 mJ / cm ^{2 of} linearly polarized ultraviolet rays for alignment treatment.

(Preparation of substrate 5 for liquid crystal display element)
The glass substrate on which the ITO electrode is formed is thoroughly washed, and a photoisomerization reaction type photo-alignment film material (trade name: LIA01, manufactured by Dainippon Ink Co., Ltd.) is spin-coated on this glass substrate, and 3 ° C. After drying for a minute, alignment treatment was performed by irradiating with linear ultraviolet polarized light of about 1000 mJ / cm ² .

[Example 1]
Ferroelectric liquid crystal (trade name: R2301, manufactured by AZ Electronic Materials) was applied on the liquid crystal display element substrate 1 using an inkjet apparatus. At this time, the head of the ink jet apparatus was heated to a temperature 20 ° C. higher than the N-phase-isotropic phase transition temperature of the ferroelectric liquid crystal, and the temperature of the liquid crystal display element substrate 1 was set to room temperature.

  Next, a sealing agent was applied to the liquid crystal display element substrate 1. The hot plate placed in the vacuum chamber was heated to 110 ° C., and the liquid crystal display element substrate 1 coated with a sealant was placed on the hot plate. Next, the liquid crystal display element substrate 2 was adsorbed by an adsorption plate, and the liquid crystal display element substrate 1 and the liquid crystal display element substrate 2 were opposed to each other so that the respective alignment treatment directions were parallel. Then, the substrates were brought into close contact with each other in a state where evacuation was performed so that the inside of the vacuum chamber became 10 Torr, and after applying a certain pressure, the inside of the vacuum chamber was returned to normal pressure. Thereafter, the ferroelectric liquid crystal was gradually cooled to room temperature to produce a liquid crystal display element.

  In the obtained liquid crystal display element, the abundance ratio of the double domain in the panel is 75:25, and when a voltage is applied so that the liquid crystal display element substrate 1 becomes a negative electrode, ferroelectricity is obtained in a region of 75%. The molecular direction of the liquid crystalline liquid crystal changed approximately twice the tilt angle of the ferroelectric liquid crystal parallel to the surface of the substrate 1 for the liquid crystal display element.

[Comparative Example 1]
A sealing agent was applied to the liquid crystal display element substrate 1. Next, the liquid crystal display element substrate 1 and the liquid crystal display element substrate 2 coated with a sealant were opposed to each other so that the respective alignment treatment directions were parallel, and thermocompression bonding was performed to produce an empty liquid crystal cell. .
Next, a ferroelectric liquid crystal (R2301, manufactured by AZ Electronic Materials) is attached to the upper portion of the injection port, and injection is performed at a temperature 10 ° C. to 20 ° C. higher than the N phase-isotropic phase transition temperature using an oven. Slowly returned to room temperature.

  In the obtained liquid crystal display element, the abundance ratio of the double domain in the panel is 51:49, and when a voltage is applied so that the liquid crystal display element substrate 1 becomes a negative electrode, ferroelectricity is generated in a region of 51%. The molecular direction of the liquid crystalline liquid crystal changed approximately twice the tilt angle of the ferroelectric liquid crystal parallel to the surface of the substrate 1 for the liquid crystal display element.

[Example 2]
Ferroelectric liquid crystal (trade name: R2301, manufactured by AZ Electronic Materials) was applied on the liquid crystal display element substrate 3 using an ink jet apparatus. At this time, the head of the ink jet apparatus was heated to a temperature 20 ° C. higher than the N-phase-isotropic phase transition temperature of the ferroelectric liquid crystal, and the temperature of the liquid crystal display element substrate 3 was set to room temperature.

  Next, a sealing agent was applied to the liquid crystal display element substrate 3. A hot plate placed in a vacuum chamber was heated to 110 ° C., and a liquid crystal display element substrate 3 coated with a sealant was placed on the hot plate. Next, the liquid crystal display element substrate 2 was adsorbed by an adsorption plate, and the liquid crystal display element substrate 3 and the liquid crystal display element substrate 2 were opposed to each other so that their alignment treatment directions were parallel. Then, the substrates were brought into close contact with each other in a state where evacuation was performed so that the inside of the vacuum chamber became 10 Torr, and after applying a certain pressure, the inside of the vacuum chamber was returned to normal pressure. Thereafter, the ferroelectric liquid crystal was gradually cooled to room temperature to produce a liquid crystal display element.

  In the obtained liquid crystal display element, the molecular direction of the ferroelectric liquid crystal changed approximately twice the tilt angle of the ferroelectric liquid crystal parallel to the surface of the liquid crystal display element substrate 3 in 98% of the panel. .

[Example 3]
Ferroelectric liquid crystal (trade name: R2301, manufactured by AZ Electronic Materials) was applied on the liquid crystal display element substrate 4 using an inkjet apparatus. At this time, the head of the inkjet apparatus was heated to a temperature 20 ° C. higher than the N-phase-isotropic phase transition temperature of the ferroelectric liquid crystal, and the temperature of the liquid crystal display element substrate 4 was set to room temperature.

  Next, a sealing agent was applied to the liquid crystal display element substrate 4. A hot plate placed in a vacuum chamber was heated to 110 ° C., and a liquid crystal display element substrate 4 coated with a sealant was placed on the hot plate. Next, the liquid crystal display element substrate 2 was adsorbed by an adsorption plate, and the liquid crystal display element substrate 4 and the liquid crystal display element substrate 2 were opposed to each other so that their alignment treatment directions were parallel. Then, the substrates were brought into close contact with each other in a state where evacuation was performed so that the inside of the vacuum chamber became 10 Torr, and after applying a certain pressure, the inside of the vacuum chamber was returned to normal pressure. Thereafter, the ferroelectric liquid crystal was gradually cooled to room temperature to produce a liquid crystal display element.

  In the obtained liquid crystal display element, the molecular direction of the ferroelectric liquid crystal changed approximately twice the tilt angle of the ferroelectric liquid crystal parallel to the surface of the substrate 4 for the liquid crystal display element in 97% of the panel. .

[Example 4]
Ferroelectric liquid crystal (trade name: R2301, manufactured by AZ Electronic Materials) was applied on the liquid crystal display element substrate 4 using an inkjet apparatus. At this time, the head of the inkjet apparatus was heated to a temperature 20 ° C. higher than the N-phase-isotropic phase transition temperature of the ferroelectric liquid crystal, and the temperature of the liquid crystal display element substrate 4 was set to room temperature.

  Next, a sealing agent was applied to the liquid crystal display element substrate 4. A hot plate placed in a vacuum chamber was heated to 110 ° C., and a liquid crystal display element substrate 4 coated with a sealant was placed on the hot plate. Next, the liquid crystal display element substrate 5 was adsorbed by an adsorption plate, and the liquid crystal display element substrate 4 and the liquid crystal display element substrate 5 were opposed to each other so that the respective alignment treatment directions were parallel. Then, the substrates were brought into close contact with each other in a state where evacuation was performed so that the inside of the vacuum chamber became 10 Torr, and after applying a certain pressure, the inside of the vacuum chamber was returned to normal pressure. Thereafter, the ferroelectric liquid crystal was gradually cooled to room temperature to produce a liquid crystal display element.

  In the obtained liquid crystal display element, the molecular direction of the ferroelectric liquid crystal changed approximately twice the tilt angle of the ferroelectric liquid crystal parallel to the surface of the liquid crystal display element substrate 4 in 99% of the panel. .

[Example 5]
The glass substrate on which the ITO electrode was formed was washed thoroughly, a transparent resist (trade name: NN780, manufactured by JSR) was spin coated on the glass substrate, dried under reduced pressure, and prebaked at 90 ° C. for 3 minutes. Subsequently, it exposed to a mask with 100 mJ / cm ² ultraviolet rays, developed with an inorganic alkali solution, and post-baked at 230 ° C. for 30 minutes. Thereby, a partition wall having a height of 1.5 μm, a width of 10 μm, and an interval of 2 mm was formed.
Next, a 2% by mass cyclopentanone solution of a photodimerization reaction type photo-alignment film material (trade name: ROP-103, manufactured by Rorlic Technology Co., Ltd.) is spin-coated on the substrate on which the partition walls are formed, and is heated at 130 ° C. After drying for 10 minutes, alignment treatment was performed by irradiating with linearly polarized ultraviolet rays of about 100 mJ / cm ² . Further, a 2% by mass cyclopentanone solution of polymerizable liquid crystal (trade name: ROF-5101, manufactured by Roric Technology) was spin-coated and dried at 55 ° C. for 3 minutes, and then non-polarized ultraviolet rays were applied at 55 ° C. Was exposed to 1000 mJ / cm ² to prepare a liquid crystal display element substrate 6.

Further, the glass substrate on which the ITO electrode is formed is thoroughly washed, and a 2% by mass cyclopentanone of a photodimerization reaction type photo-alignment film material (trade name: ROP-102, manufactured by Rorlic Technology Co., Ltd.) is formed on the glass substrate. The solution was spin-coated, dried at 130 ° C. for 10 minutes, then irradiated with about 100 mJ / cm ^{2 of} linear ultraviolet polarized light, and subjected to an alignment treatment, whereby a liquid crystal display element substrate 7 was produced.

Ferroelectric liquid crystal (trade name: R2301, manufactured by AZ Electronic Materials) was applied on the liquid crystal display element substrate 6 using an ink jet apparatus. At this time, the head of the ink jet apparatus was heated to a temperature 20 ° C. higher than the N-phase isotropic phase transition temperature of the ferroelectric liquid crystal.
Next, a sealing agent was applied to the liquid crystal display element substrate 6. A hot plate placed in a vacuum chamber was heated to 110 ° C., and a liquid crystal display element substrate 6 coated with a sealant was placed on the hot plate. Next, the liquid crystal display element substrate 7 was adsorbed by an adsorption plate, and the liquid crystal display element substrate 6 and the liquid crystal display element substrate 7 were opposed to each other so that their alignment treatment directions were parallel. Then, the substrates were brought into close contact with each other in a state where evacuation was performed so that the inside of the vacuum chamber became 10 Torr, and after applying a certain pressure, the inside of the vacuum chamber was returned to normal pressure. Thereafter, the ferroelectric liquid crystal was gradually cooled to room temperature to produce a liquid crystal display element.

  In the obtained liquid crystal display element, the molecular direction of the ferroelectric liquid crystal changed approximately twice the tilt angle of the ferroelectric liquid crystal parallel to the surface of the liquid crystal display element substrate 6 in 99% of the panel. . Moreover, the coating nonuniformity did not appear in the panel, and the contrast of the panel was 300: 1.

[Example 6]
In Example 5, a liquid crystal display element was produced in the same manner as in Example 5 except that the ferroelectric liquid crystal was applied to the liquid crystal display element substrate 7 side.

In the obtained liquid crystal display element, the molecular direction of the ferroelectric liquid crystal changed approximately twice the tilt angle of the ferroelectric liquid crystal in parallel with the surface of the substrate 7 for the liquid crystal display element in 99% of the panel. . However, coating unevenness, which was thought to have been caused by the collision of the applied liquid crystals, occurred in the panel. At this time, the contrast of the panel was 80: 1.
From Examples 5 and 6, it was found that the application of ferroelectric liquid crystal to the liquid crystal display element substrate side on which the partition walls were formed suppresses the occurrence of coating unevenness.

[Example 7]
The glass substrate on which the ITO electrode was formed was washed thoroughly, a transparent resist (trade name: NN780, manufactured by JSR) was spin coated on the glass substrate, dried under reduced pressure, and prebaked at 90 ° C. for 3 minutes. Subsequently, it exposed to a mask with 100 mJ / cm ² ultraviolet rays, developed with an inorganic alkali solution, and post-baked at 230 ° C. for 30 minutes. Thereby, a partition wall having a height of 1.5 μm, a width of 10 μm, and an interval of 2 mm was formed.
Next, a polyimide alignment film material (trade name: PIA-X771, manufactured by Chisso Petrochemical Co., Ltd.) solution was spin-coated on the substrate on which the partition walls were formed, dried at 200 ° C. for 30 minutes, and then rubbed. . Further, a 2% by mass cyclopentanone solution of polymerizable liquid crystal (trade name: ROF-5101, manufactured by Roric Technology) was spin-coated and dried at 55 ° C. for 3 minutes, and then non-polarized ultraviolet rays were applied at 55 ° C. Was exposed to 1000 mJ / cm ² to prepare a liquid crystal display element substrate 8.

Further, the glass substrate on which the ITO electrode is formed is thoroughly washed, and a 2% by mass cyclopentanone of a photodimerization reaction type photo-alignment film material (trade name: ROP-102, manufactured by Rorlic Technology Co., Ltd.) is formed on the glass substrate. The solution was spin-coated, dried at 130 ° C. for 10 minutes, then irradiated with about 100 mJ / cm ^{2 of} linear ultraviolet polarized light, and subjected to an alignment treatment, thereby producing a substrate 9 for a liquid crystal display element.

Ferroelectric liquid crystal (trade name: R2301, manufactured by AZ Electronic Materials) was applied on the liquid crystal display element substrate 8 using an ink jet apparatus. At this time, the head of the ink jet apparatus was heated to a temperature 20 ° C. higher than the N-phase isotropic phase transition temperature of the ferroelectric liquid crystal.
Next, a sealing agent was applied to the liquid crystal display element substrate 8. A hot plate placed in a vacuum chamber was heated to 110 ° C., and a liquid crystal display element substrate 8 coated with a sealant was placed on the hot plate. Next, the liquid crystal display element substrate 9 was adsorbed by an adsorption plate, and the liquid crystal display element substrate 8 and the liquid crystal display element substrate 9 were opposed to each other so that the respective alignment treatment directions were parallel. Then, the substrates were brought into close contact with each other in a state where evacuation was performed so that the inside of the vacuum chamber became 10 Torr, and after applying a certain pressure, the inside of the vacuum chamber was returned to normal pressure. Thereafter, the ferroelectric liquid crystal was gradually cooled to room temperature to produce a liquid crystal display element.

  In the obtained liquid crystal display element, the molecular direction of the ferroelectric liquid crystal changed approximately twice the tilt angle of the ferroelectric liquid crystal parallel to the surface of the substrate 8 for the liquid crystal display element in 99% of the panel. . Further, no coating unevenness or zigzag defect appeared in the panel, and the contrast of the panel was 500: 1.

[Example 8]
In Example 7, in place of the rubbing film in the liquid crystal display element substrate 8, a photo-alignment film was formed using a photo-dimerization reaction type photo-alignment film material (trade name: ROP-103, manufactured by Lorrick Technology). Produced a liquid crystal display device in the same manner as in Example 7.

In the obtained liquid crystal display element, the molecular direction of the ferroelectric liquid crystal changed approximately twice the tilt angle of the ferroelectric liquid crystal parallel to the surface of the substrate 8 for the liquid crystal display element in 99% of the panel. . However, zigzag defects occurred in the panel and the panel contrast was 300: 1.
From Examples 7 and 8, it was found that the formation of zigzag defects was suppressed by forming a reactive liquid crystal layer using polymerizable liquid crystal on the rubbing film.

It is process drawing which shows an example of the manufacturing method of the liquid crystal display element of this invention. It is a figure which shows an example of the liquid-crystal application | coating process in this invention. It is a schematic diagram which shows the behavior of a liquid crystal molecule. It is a schematic diagram which shows an example of the orientation state of a ferroelectric liquid crystal. It is a schematic diagram which shows the other example of the orientation state of a ferroelectric liquid crystal. It is a schematic diagram which shows the other example of the orientation state of a ferroelectric liquid crystal. It is explanatory drawing which shows the spontaneous polarization of a ferroelectric liquid crystal. It is a schematic diagram which shows the other example of the orientation state of a ferroelectric liquid crystal. It is a schematic sectional drawing which shows an example of the liquid crystal display element obtained by the manufacturing method of the liquid crystal display element of this invention. It is a figure which shows the drive sequence of the liquid crystal display element by a field sequential color system. It is a schematic diagram which shows the other example of the orientation state of a ferroelectric liquid crystal. It is the graph which showed the change of the transmittance | permeability with respect to the applied voltage of a ferroelectric liquid crystal. It is the figure which showed the difference in orientation by the difference in the phase sequence which a ferroelectric liquid crystal has. It is a figure which shows the other example of the liquid-crystal application | coating process in this invention. It is explanatory drawing which shows the spontaneous polarization of a ferroelectric liquid crystal. It is a schematic perspective view which shows an example of the liquid crystal display element obtained by the manufacturing method of the liquid crystal display element of this invention. It is a schematic perspective view which shows the other example of the liquid crystal display element obtained by the manufacturing method of the liquid crystal display element of this invention. It is explanatory drawing which shows the spontaneous polarization of a ferroelectric liquid crystal. It is a schematic sectional drawing which shows an example of the liquid crystal display element of this invention. It is the graph which showed the change of the transmittance | permeability with respect to the applied voltage of a ferroelectric liquid crystal. It is a figure which shows the drive sequence of the liquid crystal display element by a field sequential color system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal side substrate 2 ... 1st base material 3 ... 1st electrode layer 4 ... 1st orientation film 4 '... Reactive liquid crystal layer 5 ... Ferroelectric liquid crystal 5' ... Liquid crystal layer 6 ... Sealing agent 8 ... Partition 11 ... Counter substrate 12 ... second base material 13 ... second electrode layer 14 ... second alignment film 15 ... liquid crystal molecule z ... layer normal line Ps ... spontaneous polarization

Claims (11)

Ferroelectric liquid crystal is applied onto the first alignment film of the liquid crystal side substrate in which the first electrode layer and the first alignment film are laminated in this order on the first base material, and the liquid crystal side substrate is made to be the ferroelectric material. A liquid crystal coating step of heating the liquid crystal to a temperature exhibiting an isotropic phase or a nematic phase, and causing the ferroelectric liquid crystal to flow over the first alignment film of the liquid crystal side substrate ;
A liquid crystal side substrate coated with the ferroelectric liquid crystal, and a substrate laminating step of laminating a counter substrate having a second electrode layer formed on a second base material,
The ferroelectric liquid crystal has a phase sequence that does not pass through a smectic A phase, exhibits monostability, and exhibits HV-shaped switching (half-V shaped switching) characteristics,
When a voltage is applied to the ferroelectric liquid crystal so that the first electrode layer is a negative electrode, the molecular direction of the ferroelectric liquid crystal is parallel to the liquid crystal side substrate surface. A method for producing a liquid crystal display element, characterized in that the tilt angle changes about twice as much. Before the liquid crystal application step, perform a liquid crystal side substrate preparation step of preparing the liquid crystal side substrate,
The liquid crystal side substrate preparation step includes a reactive liquid crystal layer forming step of forming a reactive liquid crystal layer formed by fixing a reactive liquid crystal on the first alignment film,
The method for manufacturing a liquid crystal display element according to claim 1, wherein the ferroelectric liquid crystal is applied on the reactive liquid crystal layer in the liquid crystal application step.   The method for manufacturing a liquid crystal display element according to claim 2, wherein the first alignment film is a rubbing film that has been subjected to a rubbing treatment. Before the liquid crystal application step, perform a liquid crystal side substrate preparation step of preparing the liquid crystal side substrate,
The liquid crystal side substrate preparing step includes a first alignment film forming step of forming the first alignment film on the first electrode layer, and the first alignment film forming step includes the first alignment film by a photo-alignment process. 2. The method for producing a liquid crystal display element according to claim 1, wherein an alignment film is formed. Before the liquid crystal application step, perform a liquid crystal side substrate preparation step of preparing the liquid crystal side substrate,
The liquid crystal side substrate preparation step includes a partition formation step of forming a partition on the first substrate, and forming the first alignment film on the first substrate on which the partition and the first electrode layer are formed. The method for producing a liquid crystal display element according to claim 1, further comprising a first alignment film forming step. Before the substrate bonding step, perform a counter substrate preparation step of preparing the counter substrate,
6. The liquid crystal display according to claim 1, wherein the counter substrate preparing step includes a second alignment film forming step of forming a second alignment film on the second electrode layer. Device manufacturing method.   The method for manufacturing a liquid crystal display element according to claim 6, wherein in the second alignment film forming step, the second alignment film is formed by a photo-alignment process.   In the liquid crystal application step, the ferroelectric liquid crystal is heated to a temperature at which the ferroelectric liquid crystal exhibits a nematic phase or an isotropic phase, and the liquid crystal side substrate is set to room temperature. The method of manufacturing a liquid crystal display element according to claim 1, wherein the ferroelectric liquid crystal is applied on the surface by a discharge method.   The method for manufacturing a liquid crystal display element according to claim 8, wherein the discharge method is an inkjet method. A first base material, a first electrode layer and a partition formed on the first base, a first alignment film formed on the first electrode layer and the partition, and on the first alignment film A liquid crystal side substrate having a reactive liquid crystal layer formed and formed by immobilizing reactive liquid crystals,
A second alignment material, a second electrode layer formed on the second substrate, and a photo-alignment film formed on the second electrode layer and containing a photodimerization type material or a photoisomerization type material. A counter substrate having a second alignment film, and a liquid crystal layer formed between a reactive liquid crystal layer of the liquid crystal side substrate and a second alignment film of the counter substrate, and including a ferroelectric liquid crystal,
The partition walls are formed in a matrix shape or a frame shape,
The ferroelectric liquid crystal has a phase sequence that does not pass through a smectic A phase, exhibits monostability, and exhibits HV-shaped switching (half-V shaped switching) characteristics,
When a voltage is applied to the ferroelectric liquid crystal so that the first electrode layer is a negative electrode, the molecular direction of the ferroelectric liquid crystal is parallel to the liquid crystal side substrate surface. A liquid crystal display element characterized by changing about twice the tilt angle.   The liquid crystal display element according to claim 10, wherein the first alignment film is a rubbing film subjected to a rubbing process.

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