JP2010271475A - Liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display element in which leakage of light is reduced in an area where a step due to a TFT (Thin Film Transistor) element or the like is present. <P>SOLUTION: The liquid crystal display element has a TFT substrate, a common electrode substrate, and a driving liquid crystal layer. The TFT substrate includes: a first substrate; a TFT electrode layer formed on the first substrate and having a plurality of TFT elements and a pixel electrode connected to the TFT elements; a reactive liquid crystal alignment layer formed on the TFT electrode layer; and a fixed liquid crystal layer formed on the reactive liquid crystal alignment layer and obtained by fixing the reactive liquid crystals. The common electrode substrate includes a second substrate and a common electrode formed on the second substrate. The driving liquid crystal layer is formed between the fixed liquid crystal layer of the TFT substrate and the common electrode of the common electrode substrate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid crystal display element using a thin film transistor (TFT).

  An active matrix liquid crystal display device using an active element such as a thin film transistor (hereinafter, the thin film transistor may be referred to as a TFT) is widely used as a display device because of its thinness, light weight, high image quality, and the like. In an active matrix liquid crystal display device, a thin film transistor substrate on which TFT elements and pixel electrodes are formed (hereinafter, the thin film transistor substrate may be referred to as a TFT substrate) and a common electrode substrate disposed to face the TFT substrate. A liquid crystal is sandwiched between them, a voltage is applied between the pixel electrode of the TFT substrate and the common electrode of the common electrode substrate to drive the liquid crystal, and an incident light is modulated and emitted to form an image.

  In the TFT substrate, for example, a gate line and a gate electrode connected to the gate line are formed on the substrate, a gate insulating layer is formed to cover the gate line and the gate electrode, a semiconductor layer is formed on the gate insulating layer, A source line is formed so as to cross the gate line, a source electrode and a drain electrode connected to the source line are formed on the semiconductor layer, and a pixel electrode connected to the drain electrode is formed. Further, in a TFT substrate used in a liquid crystal display device, an alignment film is formed so as to cover TFT elements such as a semiconductor layer, a source electrode, a drain electrode, and a drain electrode, and a pixel electrode.

  A TFT substrate has steps on the substrate surface due to wiring such as gate lines and source lines, semiconductor layers, TFT elements such as gate electrodes, source electrodes, and drain electrodes, pixel electrodes, and the like. There is a problem that light leakage occurs.

In order to solve this problem, a method has been proposed in which a light shielding portion is formed on a common electrode substrate to conceal liquid crystal alignment defects. However, when the light shielding portion is provided on the common electrode substrate, there are problems that the aperture ratio becomes low and the manufacturing process becomes complicated because alignment is required.
In addition, for the purpose of flattening the step, it has been proposed to form a flattening layer on the wiring, TFT element, and pixel electrode (see, for example, Patent Document 1). However, when a planarization layer is provided, there is a problem that the drive voltage increases. Further, it is conceivable to form a thick alignment film in order to flatten the step, but there is a problem that the drive voltage becomes high as in the above case.

By the way, the present inventors have proposed using an immobilized liquid crystal layer formed by immobilizing reactive liquid crystals as an alignment film for aligning liquid crystal molecules (see, for example, Patent Document 2 and Patent Document 3). In this fixed liquid crystal layer, a reactive liquid crystal composition is applied on a general alignment film such as a rubbing film or a photo-alignment film, the reactive liquid crystal is aligned, and then the alignment state of the reactive liquid crystal is fixed. Is formed. Reactive liquid crystal is aligned by alignment regulating force such as rubbing film and photo-alignment film, and the alignment state of reactive liquid crystal is fixed in the fixed liquid crystal layer, so the fixed liquid crystal layer aligns the liquid crystal molecules. It acts as an alignment film.
For example, Patent Document 4 and Patent Document 5 also propose use of a polymer compound exhibiting liquid crystallinity for the alignment film for aligning liquid crystal molecules.

Japanese Patent Laid-Open No. 11-142870 JP 2005-258428 A JP 2006-350322 A JP-A-1-105912 JP 2003-172935 A

In recent years, high contrast is demanded as one of the high image quality performances of liquid crystal display devices, and it is required to reduce light leakage (white spots) as much as possible.
As a result of intensive studies on the relationship between the light leakage (white spots) due to the above steps and the type and thickness of the alignment film, the present inventors simply formed a thick general alignment film such as a rubbing film or a photo alignment film. Then, it turned out that the light leakage by a level difference cannot fully be improved. In other words, it has been found that flattening the step is not sufficient to improve light leakage due to the step.
The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a liquid crystal display element capable of reducing light leakage in a region where a step due to a TFT element or the like exists.

  Therefore, the present inventors paid attention to the difference between the formation process of a general alignment film such as a rubbing film or a photo-alignment film and the formation process of the above-mentioned fixed liquid crystal layer. Unlike the formation process of a general alignment film such as a rubbing film or a photo-alignment film, the formation process of the fixed liquid crystal layer undergoes an alignment process for aligning the reactive liquid crystal. This difference in the formation process was thought to affect the alignment failure of the liquid crystal due to the step. Until now, research based on the knowledge that the fixed liquid crystal layer is useful for controlling the alignment of the driving liquid crystal in the driving liquid crystal layer has been conducted. There has been little investigation into the relationship. Then, the present inventors have found that when a fixed liquid crystal layer is applied as an alignment film formed on the TFT substrate, light leakage due to steps such as TFT elements is remarkably improved, and the present invention is based on this finding. It came to complete.

That is, the present invention is formed on a first substrate, a TFT electrode layer formed on the first substrate and having a plurality of TFT elements and pixel electrodes connected to the TFT elements, and the TFT electrode layer. A TFT substrate having an alignment film for reactive liquid crystal and an immobilized liquid crystal layer formed on the alignment film for reactive liquid crystal and formed by immobilizing reactive liquid crystal;
A common electrode substrate having a second substrate and a common electrode formed on the second substrate;
There is provided a liquid crystal display element comprising: the fixed liquid crystal layer of the TFT substrate; and a driving liquid crystal layer formed between the common electrodes of the common electrode substrate.

  According to the present invention, since the fixed liquid crystal layer is formed on the TFT electrode layer in the TFT substrate, it is possible to suppress the alignment failure of the driving liquid crystal in a region where there is a step due to the TFT element or the like, and light leakage. (White spots) can be reduced. This is because the fixed liquid crystal layer is formed by, for example, applying a reactive liquid crystal composition containing a reactive liquid crystal and a solvent on an alignment film for reactive liquid crystal, drying the solvent in the reactive liquid crystal composition, This is considered to be related to the process of forming the immobilized liquid crystal layer, which is formed by polymerizing the reactive liquid crystal after aligning the liquid crystal. That is, since the reactive liquid crystal flows on the reactive liquid crystal alignment film and exhibits a liquid crystal phase, it is assumed that the alignment defect of the driving liquid crystal due to the step can be reduced.

  In the said invention, it is preferable that the said TFT substrate has a light-shielding part formed on the said TFT element. As a result, it is possible to prevent a malfunction caused by irradiating the semiconductor layer with light, resulting in a display defect. In this case, by providing the light shielding portion on the TFT substrate instead of providing the light shielding portion on the common electrode substrate, alignment becomes unnecessary and the manufacturing process can be simplified. Furthermore, since no alignment is required, the aperture ratio can be increased. In addition, in a region where a step due to the light-shielding portion exists, a light-shielding portion that causes surface irregularities is provided on the TFT substrate having the immobilized liquid crystal layer, and the fixed liquid crystal layer is formed so as to cover the light-shielding portion It is possible to suppress the occurrence of poor alignment of the driving liquid crystal and reduce light leakage (whiteout).

  In the present invention, it is preferable that the TFT substrate has a spacer formed on a non-pixel region of the TFT electrode layer. This is because providing the spacer on the TFT substrate instead of providing the spacer on the common electrode substrate makes alignment unnecessary and simplifies the manufacturing process. In addition, a spacer that causes surface irregularities is provided on the TFT substrate having the fixed liquid crystal layer, and the fixed liquid crystal layer is formed so as to cover the spacer. It is possible to suppress alignment failure and reduce light leakage (whiteout).

  Furthermore, in the present invention, the driving liquid crystal layer preferably contains a ferroelectric liquid crystal. This is because the ferroelectric liquid crystal has higher molecular ordering than the nematic liquid crystal, so that it is difficult to control the alignment and alignment defects are particularly likely to occur in a region where there is a step due to a TFT element or the like. In the present invention, since the alignment defect of the driving liquid crystal can be reduced in a region where there is a step due to a TFT element or the like, even if the driving liquid crystal layer includes the ferroelectric liquid crystal, the alignment of the ferroelectric liquid crystal Defects can be reduced.

  In the present invention, the common electrode substrate has a second alignment film formed on the common electrode, and the driving liquid crystal layer is formed between the fixed liquid crystal layer and the second alignment film. Preferably it is. This is because the alignment of the driving liquid crystal can be effectively controlled by forming the driving liquid crystal layer between the fixed liquid crystal layer and the second alignment film.

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

  In the present invention, the reactive liquid crystal preferably contains a polymerizable liquid crystal monomer. 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.

  Furthermore, the liquid crystal display element of the present invention is preferably driven by a field sequential method. In the field sequential method, since it is not necessary to provide a color filter on the common electrode substrate, the aperture ratio can be increased and alignment is not necessary when the light shielding portion and the spacer are formed on the TFT substrate. The manufacturing process can be simplified.

  In the present invention, since the fixed liquid crystal layer is formed on the TFT electrode layer of the TFT substrate, there is an effect that light leakage can be reduced in a region where a step due to the TFT element or the like exists.

It is a schematic sectional drawing which shows an example of the liquid crystal display element of this invention. It is a schematic sectional drawing which shows the other example of the liquid crystal display element of this invention. It is a schematic diagram which shows the behavior of a liquid crystal molecule. It is the graph which showed the change of the transmitted light amount with respect to the applied voltage of a ferroelectric liquid crystal. 2 is a polarizing microscope photograph of liquid crystal display elements of Example 1 and Comparative Example 1. FIG.

Hereinafter, the liquid crystal display element of the present invention will be described in detail.
The liquid crystal display element of the present invention is formed on a first substrate, a TFT electrode layer formed on the first substrate and having a plurality of TFT elements and pixel electrodes connected to the TFT elements, and the TFT electrode layer. A TFT substrate having a reactive liquid crystal alignment film formed thereon, and an immobilized liquid crystal layer formed on the reactive liquid crystal alignment film and formed by fixing the reactive liquid crystal;
A common electrode substrate having a second substrate and a common electrode formed on the second substrate;
And a driving liquid crystal layer formed between the fixed liquid crystal layer of the TFT substrate and the common electrode of the common electrode substrate.

The liquid crystal display element of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example of the liquid crystal display element of the present invention. As illustrated in FIG. 1, the liquid crystal display element 1 has a driving liquid crystal layer 41 formed between a TFT substrate 11 and a shared electrode substrate 31. The TFT substrate 11 is formed on a first substrate 12, a TFT electrode layer formed on the first substrate 12, having a plurality of TFT elements 21 and pixel electrodes 13 connected to the TFT elements 21, and the TFT electrode layer. The reactive liquid crystal alignment film 14 and the fixed liquid crystal layer 15 formed on the reactive liquid crystal alignment film 14 are provided. In the fixed liquid crystal layer 15, the alignment state of the reactive liquid crystal is fixed. The TFT element 21 includes a gate electrode 22, a gate insulating film 23 formed on the gate electrode 22, a semiconductor layer 24 formed on the gate insulating film 23, and a predetermined interval on the semiconductor layer 24. The pixel electrode 13 is connected to the drain electrode 26. The source electrode 25 and the drain electrode 26 are formed so as to face each other. On the other hand, the common electrode substrate 31 includes a second substrate 32, a common electrode 33 formed on the second substrate 32, and a second alignment film 34 formed on the common electrode 33.

In the case of a general alignment film such as a rubbing film or a photo-alignment film, if there is a step on the film surface due to a TFT element or the like, a uniform alignment is required when performing an alignment process such as a rubbing process or a photo-alignment process Processing cannot be performed, resulting in uneven alignment processing. As a result, an alignment defect of the driving liquid crystal occurs in a region where a step due to a TFT element or the like exists.
On the other hand, the fixed liquid crystal layer is formed by, for example, applying a reactive liquid crystal composition containing a reactive liquid crystal and a solvent on an alignment film for reactive liquid crystal, drying the solvent in the reactive liquid crystal composition, After the alignment, it is formed by polymerizing reactive liquid crystals. Further, even if the alignment treatment unevenness occurs in the reactive liquid crystal alignment film due to the step, the reactive liquid crystal flows on the reactive liquid crystal alignment film and exhibits a liquid crystal phase. Compared with the case where an alignment film or the like is formed, it is possible to reduce the alignment failure of the driving liquid crystal due to the step.
Therefore, in the present invention, the fixed liquid crystal layer is formed on the TFT electrode layer of the TFT substrate, and the driving liquid crystal layer is formed in direct contact with the fixed liquid crystal layer, so that there is a step due to the TFT element or the like. It is possible to suppress the occurrence of poor alignment of the driving liquid crystal in the region, and to effectively reduce light leakage (whiteout).

  In addition, when the immobilized liquid crystal layer is formed on the reactive liquid crystal alignment film, the reactive liquid crystal is aligned by the reactive liquid crystal alignment film, and the reaction is performed by, for example, irradiating ultraviolet rays to polymerize the reactive liquid crystal. The alignment state of the conductive liquid crystal can be fixed. Thereby, the alignment regulating force with respect to the driving liquid crystal can be applied to the fixed liquid crystal layer. Further, since the reactive liquid crystal is fixed, it has an advantage that it is not affected by temperature or the like. Furthermore, the reactive liquid crystal is relatively similar in structure to the ferroelectric liquid crystal and has a strong interaction with the driving liquid crystal, so that the alignment of the driving liquid crystal can be controlled effectively.

  Hereinafter, each component of the liquid crystal display element of the present invention will be described in detail.

1. TFT substrate The TFT substrate used in the present invention includes a first substrate, a TFT electrode layer formed on the first substrate and having a plurality of TFT elements and pixel electrodes connected to the TFT elements, and the TFT electrode layer. It has an alignment film for reactive liquid crystal formed thereon, and an immobilized liquid crystal layer formed on the reactive liquid crystal alignment film and formed by immobilizing reactive liquid crystal.
Hereinafter, each configuration of the TFT substrate will be described.

(1) Immobilized liquid crystal layer The immobilized liquid crystal layer used in the present invention is formed on an alignment film for reactive liquid crystal, and is formed by immobilizing reactive liquid crystal.

  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 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.

  As the monoacrylate monomer and diacrylate monomer, those described in JP 2006-350322 A, JP 2006-323214 A, JP 2005-258429 A, JP 2005-258428 A, and the like are used. it can.

  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 does not have to exhibit 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.

  In this invention, you may add a photoinitiator etc. to the said reactive liquid crystal as needed. A photopolymerization initiator as described in JP-A-2005-258428 can be used. 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. The addition amount of the photopolymerization initiator is generally in the range of 0.01% by mass to 20% by mass, preferably 0.1% by mass to 10% by mass, more preferably 0.5% by mass to 5% by mass. Can be added to the reactive liquid crystal.

  The thickness of the fixed 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, and preferably within a range of 3 nm to 100 nm. If the fixed liquid crystal layer is too thick, the optical anisotropy of the fixed liquid crystal layer may affect the display, and if the fixed liquid crystal layer is too thin, a portion where the fixed liquid crystal layer is not formed is generated. Because there are cases.

  The fixed liquid crystal layer is formed by coating the reactive liquid crystal composition containing the reactive liquid crystal and the solvent on the alignment film for reactive liquid crystal, aligning the reactive liquid crystal, and then polymerizing the reactive liquid crystal to react the reactive liquid crystal. It can be formed by fixing the orientation state.

  The solvent used in the reactive liquid crystal composition is not particularly limited as long as it can dissolve the reactive liquid crystal and the like and does not inhibit the alignment ability of the alignment film for reactive liquid crystal. As such a solvent, for example, a solvent described in JP-A-2005-258428 can be used. A solvent may be used independently and may use 2 or more types together.

  Further, if only a single kind of solvent is used, the solubility of the reactive liquid crystal or the like may be insufficient, or the reactive liquid crystal 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. Of the above-mentioned solvents, preferred as a single solvent are ketones, and preferred as a mixed solvent is a mixed system of ethers, ketones and a glycol solvent. Of these, a mixed solvent in which two or three types are combined, particularly three mixed solvents are preferable.

  Although the concentration of the reactive liquid crystal composition depends on the solubility of the reactive liquid crystal and the thickness of the immobilized liquid crystal layer, it cannot be defined unconditionally, but is usually 0.1% by mass to 40% by mass, preferably 1% by mass. It adjusts in the range of% -20 mass%. If the concentration of the reactive liquid crystal composition is lower than the above range, the reactive liquid crystal may be difficult to align. Conversely, if the concentration of the reactive liquid crystal composition is higher than the above range, the viscosity of the reactive liquid crystal composition is low. It is because it becomes high and it may become difficult to form a uniform coating film.

  Furthermore, a compound such as that described in JP-A-2005-258428 can be added to the reactive liquid crystal composition as long as the object of the present invention is not impaired. 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 fixed liquid crystal layer, and improves its stability.

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

  In addition, the solvent is removed after the reactive liquid crystal composition is applied, and the removal of the solvent is performed by, for example, removal under reduced pressure or removal by heating, or a combination thereof.

  In the present invention, the reactive liquid crystal applied as described above is aligned by the alignment film for reactive liquid crystal 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 below the NI transition point. Here, the NI transition point indicates the temperature at which the liquid crystal phase transitions to the isotropic phase.

  In order to fix the alignment state of the reactive liquid crystal, a method of irradiating active radiation that activates polymerization is used. The active radiation as used herein refers to radiation capable of causing polymerization of the reactive liquid crystal. If necessary, a photopolymerization initiator may be included in the reactive liquid crystal. Such actinic radiation is not particularly limited as long as it is a radiation capable of polymerizing the reactive liquid crystal, but usually ultraviolet light or visible light is used from the viewpoint of the ease of the apparatus. . In addition, about irradiation of actinic radiation, it can be made the same as that of description of Unexamined-Japanese-Patent No. 2005-258428.

  Irradiation with such an active irradiation beam may be performed under a temperature condition in which the reactive liquid crystal becomes a liquid crystal phase, or may be performed at a temperature lower than a temperature at which the liquid crystal phase becomes. This is because the reactive liquid crystal once in the liquid crystal phase does not suddenly disturb the alignment state even if the temperature is lowered thereafter.

  As a method for fixing the alignment state of the reactive liquid crystal, in addition to the method of irradiating the active radiation, a method of heating and polymerizing the reactive liquid crystal can be used. The reactive liquid crystal used in this case is preferably a polymerizable liquid crystal monomer that undergoes thermal polymerization at a temperature below the NI transition point.

(2) Alignment film for reactive liquid crystal As the alignment film for reactive liquid crystal used in the present invention, the above-mentioned reactive liquid crystal can be aligned, and there is an adverse effect in fixing the alignment state of the above-mentioned reactive liquid crystal. There is no particular limitation as long as it does not reach. As the alignment film for reactive liquid crystal, for example, a rubbing-treated alignment film, a photo-alignment-treated photo-alignment film, an oblique vapor deposition alignment film, or the like can be used.

  The rubbing-treated alignment film is useful in that a relatively high pretilt angle can be realized. As the alignment film subjected to the rubbing treatment, for example, those described in JP-A-2008-129529 can be used.

  The photo-alignment film irradiates a substrate coated with a photo-excited reaction type material with light with controlled polarization to cause photo-excited reaction (decomposition, isomerization, dimerization) and to give anisotropy to the obtained film. This aligns the liquid crystal molecules on the film. The photo-alignment film is useful in that 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. Photoexcitation materials used for photo-alignment films include photoisomerization materials that impart anisotropy to the film by photoisomerization reaction, and anisotropy to the film by photodimerization reaction. And a photodecomposable material that imparts anisotropy to the film by causing a photodecomposition reaction. As the photo-alignment film, for example, those described in JP-A-2006-350322, JP-A-2006-323214, JP-A-2005-258429, and JP-A-2005-258428 can be used.

  The oblique vapor deposition alignment film is formed by an oblique vapor deposition method. The oblique deposition film is useful in that a relatively high pretilt angle can be realized. As the oblique deposition alignment film, for example, those described in International Publication WO2008 / 075732 Pamphlet can be used.

(3) Light-shielding part In this invention, it is preferable that a TFT substrate has a light-shielding part formed on the TFT element. For example, as shown in FIG. 2, the light shielding portion 27 is preferably formed on the semiconductor layer 22. As a result, it is possible to prevent a malfunction caused by irradiating the semiconductor layer with light, resulting in a display defect. Further, by providing the light shielding portion on the TFT substrate instead of providing the light shielding portion on the common electrode substrate, alignment becomes unnecessary, the manufacturing process can be simplified, and the aperture ratio can be increased. Further, the TFT substrate is provided with a light shielding portion, and the fixed liquid crystal layer is formed so as to cover the light shielding portion. Leakage (whiteout) can be reduced.

  The light shielding part is not particularly limited as long as it is made of a material having a desired light shielding property, but is usually made of a metal material or a material made of a light shielding material and a resin. When the light shielding part is made of a metal material, the metal material is not particularly limited as long as it has a desired light shielding property, but a chromium material is generally used. On the other hand, when the light shielding part is composed of a light shielding material and a resin, examples of the light shielding material include light shielding particles such as carbon fine particles, metal oxides, inorganic pigments, and organic pigments. Moreover, as resin, what is generally used for the resin-made light-shielding part is employable.

  The light shielding portion may be formed on the semiconductor layer. When the light shielding part is made of a metal material, an insulating layer is preferably formed between the light shielding part and the semiconductor layer.

  The thickness of the light shielding part can be, for example, about 200 nm to 500 nm when the light shielding part is made of a metal material. On the other hand, when the light shielding portion is made of a light shielding material and a resin, the thickness of the light shielding portion can be set to about 0.3 μm to 2 μm, for example.

(4) Spacer In the present invention, the TFT substrate preferably has a spacer formed on the non-pixel region of the TFT electrode layer. This is because providing the spacer on the TFT substrate instead of providing the spacer on the common electrode substrate makes alignment unnecessary and simplifies the manufacturing process. In this case, as illustrated in FIG. 2, the spacer 16 is formed on the first substrate 12, and the reactive liquid crystal alignment film 14 and the fixed liquid crystal layer 15 are formed so as to cover the spacer 16. Since the fixed liquid crystal layer is formed so as to cover the spacer, it is possible to suppress the alignment defect of the driving liquid crystal in a region where a step due to the spacer exists and to reduce light leakage (whiteout).

  Examples of the spacer include partition walls and columnar spacers, and are appropriately selected according to the type of driving liquid crystal used in the driving liquid crystal layer. For example, columnar spacers are formed when nematic liquid crystal is used for the driving liquid crystal layer, and barrier ribs are formed when ferroelectric liquid crystal is used for the driving liquid crystal layer.

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

  In addition, the arrangement of the spacers is preferably on a non-pixel region. Since the drive liquid crystal is likely to be poorly aligned in the vicinity of the spacer, the spacer is preferably formed in a non-pixel region that does not affect image display. For example, spacers can be provided over wiring such as gate lines and source lines.

  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.

A plurality of spacers are formed, and it is preferable that the plurality of spacers are regularly formed at predetermined positions. In particular, in the case where the spacer is a partition and a liquid crystal display element is manufactured by a coating method (drop method), it is preferable that the partition is formed substantially 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 driving liquid crystal.
The pitch and width of the spacers may be general ones. In addition, the height of the spacer is usually about the same as the cell gap.
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.

(5) TFT electrode layer The TFT electrode layer in the present invention has a plurality of TFT elements and pixel electrodes connected to the TFT elements.

As illustrated in FIG. 1, the TFT element includes a gate electrode 22, a gate insulating film 23 formed on the gate electrode 22, a semiconductor layer 24 formed on the gate insulating film 23, and a semiconductor layer 24. The pixel electrode 13 is connected to the drain electrode 26. The source electrode 25 and the drain electrode 26 are formed so as to face each other with a predetermined interval.
The TFT element is not particularly limited, and is appropriately selected according to the type of the liquid crystal display element of the present invention. For example, the TFT element may have an a-Si TFT structure, and has a p-Si TFT structure. It may be a thing. In the case of a TFT element having an a-Si TFT structure, either a normal stagger type (top gate structure) or an inverted stagger type (bottom gate structure) may be used. In the case of an inverted stagger type, either a channel etch type or a channel protect type may be used. On the other hand, in the case of a TFT element having a p-Si TFT structure, either a planar type or a stagger type may be used. Among them, in the present invention, it is preferable that the TFT element has a large step since the alignment defect of the driving liquid crystal can be reduced in a region where the step due to the TFT element exists.

  The pixel electrode is not particularly limited as long as it is generally used as a pixel electrode of a liquid crystal display element. For example, indium oxide, tin oxide, indium tin oxide (ITO), indium tin oxide (IZO), etc. Is preferably used.

(6) 1st board | substrate The 1st board | substrate used for this invention will not be specifically limited if generally used as a board | substrate of a liquid crystal display element, For example, a glass plate, a plastic plate, etc. are mentioned preferably.

2. Driving liquid crystal layer The driving liquid crystal layer in the present invention is formed between the fixed liquid crystal layer of the TFT substrate and the common electrode of the common electrode substrate.

  The driving liquid crystal used for the driving liquid crystal layer is not particularly limited as long as it is a liquid crystal material in a horizontal alignment mode. The liquid crystal material in the horizontal alignment mode refers to a liquid crystal material that is aligned substantially horizontally with respect to the substrate when no voltage is applied. Examples of such a liquid crystal material include a smectic liquid crystal such as a nematic liquid crystal and a ferroelectric liquid crystal. Among them, in the present invention, it is preferable that the driving liquid crystal layer includes a ferroelectric liquid crystal. This is because the ferroelectric liquid crystal has higher molecular ordering than the nematic liquid crystal, so that it is difficult to control the alignment and alignment defects are particularly likely to occur in a region where there is a step due to a TFT element or the like. In the present invention, since the alignment defect of the driving liquid crystal can be reduced in a region where there is a step due to a TFT element or the like, even if the driving liquid crystal layer includes the ferroelectric liquid crystal, the alignment of the ferroelectric liquid crystal Defects can be reduced.

The ferroelectric liquid crystal used in the present invention is not particularly limited as long as it exhibits a chiral smectic C (SmC ^* ) phase. As the phase series of the ferroelectric liquid crystal, for example, a phase change between a nematic (N) phase, a cholesteric (Ch) phase, a chiral smectic C (SmC ^* ) phase, and a nematic (N) phase-chiral smectic C are possible. Phase change with (SmC ^* ) phase, Nematic (N) phase-Smectic A (SmA) phase-Chiral smectic C (SmC ^* ) phase, Nematic (N) phase-Cholesteric (Ch) phase- Examples thereof include those that change phase with a smectic A (SmA) phase-chiral smectic C (SmC ^* ) phase.

  In addition, as the ferroelectric liquid crystal, either one showing bistability or one showing monostability can be used. Among these, ferroelectric liquid crystal exhibiting monostability is preferable. When a ferroelectric liquid crystal exhibiting monostability is used, gradation display is possible by continuously changing the director of the liquid crystal (inclination of the molecular axis) by voltage change and analog modulation of the transmitted light intensity. Because it becomes. In particular, when the liquid crystal display element is driven by a field sequential color system, it is preferable to use a ferroelectric liquid crystal exhibiting monostability. By using a ferroelectric liquid crystal exhibiting monostability, it is possible to drive using an active matrix method using TFTs, and to control gradation by voltage modulation, realizing high-definition and high-quality display. Because it can be done.

  “Showing monostability” means a state in which the state of the ferroelectric liquid crystal when no voltage is applied is stabilized in one state. As illustrated in FIGS. 3A to 3C, the ferroelectric liquid crystal has a cone ridge line in which the liquid crystal molecules 42 are inclined from the layer normal line z and have a bottom surface perpendicular to the layer normal line z. Rotate along. In such a cone, the tilt angle of the liquid crystal molecules 42 with respect to the layer normal z is referred to as a tilt angle θ. Thus, the liquid crystal molecules 42 can operate on the cone between two states inclined by a tilt angle ± θ with respect to the layer normal z. Specifically, the expression of monostability refers to a state in which the liquid crystal molecules 42 are stabilized in any one state on the cone when no voltage is applied.

  Among ferroelectric liquid crystals exhibiting monostability, half V-shaped switching characteristics in which liquid crystal molecules operate only when a positive or negative voltage is applied, as illustrated in FIGS. 4 (a) and 4 (b). It is preferable to show this. Using a ferroelectric liquid crystal exhibiting such a half V-shaped switching characteristic, it is possible to take a sufficiently long opening time as a black and white shutter, thereby making it possible to display each color that is temporally switched brighter. This is because a bright color display liquid crystal display element can be realized.

  The “half V-shaped switching characteristic” refers to an electro-optical characteristic in which the amount of transmitted light is asymmetric with respect to an applied voltage. Specifically, among the transmitted light amounts with respect to the applied voltage when a positive and negative voltage of 10 V is applied to the liquid crystal layer, A is the transmitted light amount of the applied voltage when the transmitted light amount is small, and the applied voltage is transmitted when the transmitted light amount is large. When the amount of light is B, B / A is 2 or more.

Such a ferroelectric liquid crystal can be variously selected from generally known liquid crystal materials according to required characteristics. In particular, a ferroelectric liquid crystal that exhibits an SmC ^* phase from the Ch phase without passing through the SmA phase is suitable as a material exhibiting half V-shaped switching characteristics. Specifically, “R2301” manufactured by AZ Electronic Materials, Inc. ". Specific examples of the ferroelectric liquid crystal via the SmA phase include “FELIXM4851-100” manufactured by AZ Electronic Materials.

  When the driving liquid crystal layer includes a ferroelectric liquid crystal, the driving liquid crystal layer may contain other compounds in addition to the ferroelectric liquid crystal. As other compounds, those having an arbitrary function can be used depending on the function required for the liquid crystal display element. Examples of other compounds that can be suitably used include a polymer of a polymerizable monomer. This is because when the polymer of the polymerizable monomer is contained in the driving liquid crystal layer, the alignment of the ferroelectric liquid crystal is so-called “polymer stabilization” and excellent alignment stability can be obtained. The case where the drive liquid crystal layer contains a ferroelectric liquid crystal and a polymer of a polymerizable monomer is the same as that described in JP-A-2006-323215.

  The thickness of the driving liquid crystal layer is appropriately selected according to the type of driving liquid crystal used for the driving liquid crystal layer. For example, when the driving liquid crystal layer includes a ferroelectric liquid crystal, the thickness of the driving liquid crystal layer is preferably within a range of 1.2 μm to 3.0 μm, more preferably 1.3 μm to 2.5 μm, and even more preferably. Is in the range of 1.4 μm to 2.0 μm. If the driving liquid crystal layer is too thin, the maximum transmittance of the liquid crystal display element may not be sufficiently large. If the driving liquid crystal layer is too thick, the ferroelectric liquid crystal may be difficult to align. is there.

As a method for sandwiching the driving liquid crystal between the fixed liquid crystal layer of the TFT substrate and the common electrode of the common electrode substrate, a method generally used as a method for producing a liquid crystal cell can be used, for example, a vacuum injection method, coating A method (dropping method) or the like can be used.
In the vacuum injection method, for example, a driving liquid crystal that is made isotropic liquid by heating is injected into a liquid crystal cell that has been prepared in advance using a TFT substrate and a common electrode substrate, and sealed with an adhesive. By doing so, the driving liquid crystal can be sandwiched between the TFT substrate and the common electrode substrate.
On the other hand, in the dropping method, for example, a heated driving liquid crystal is dropped on the fixed liquid crystal layer of the TFT substrate, a sealant is applied to the peripheral edge of the common electrode substrate, and the TFT substrate and the common electrode substrate are stacked under reduced pressure. In addition, the driving liquid crystal can be sandwiched between the TFT substrate and the common electrode substrate by bonding them with a sealant. In particular, in the case of the dropping method, it is preferable to apply the driving liquid crystal on the fixed liquid crystal layer of the TFT substrate. This is because, since the fixed liquid crystal layer can effectively control the alignment of the driving liquid crystal, it is preferable to apply the driving liquid crystal on the fixed liquid crystal layer in consideration of the initial alignment. In addition, as described above, it is preferable that a spacer is formed on the TFT substrate.

After the driving liquid crystal is sandwiched between the TFT substrate and the common electrode substrate, the driving liquid crystal is aligned. At this time, the encapsulated driving liquid crystal can be aligned by slowly cooling the liquid crystal cell to room temperature.
In particular, when the driving liquid crystal layer includes a ferroelectric liquid crystal, it is preferable to align the ferroelectric liquid crystal without performing an electric field application process. When the second alignment film is formed on the common electrode substrate and the ferroelectric liquid crystal is sandwiched between the fixed liquid crystal layer of the TFT substrate and the second alignment film of the common electrode substrate, an electric field application process is performed. And by slowly cooling the ferroelectric liquid crystal without performing the steps, the alignment ability of the fixed liquid crystal layer and the second alignment film, and the surface of the fixed liquid crystal layer and the second alignment film on the ferroelectric liquid crystal This is because the direction of spontaneous polarization can be controlled by aligning the ferroelectric liquid crystal by the polar interaction. Therefore, since the ferroelectric liquid crystal is aligned without performing an electric field application treatment, it is possible to maintain the alignment even when the temperature is raised above the phase transition temperature, and to suppress the occurrence of alignment defects.

  When a ferroelectric liquid crystal is used and a polymerizable monomer is added to the ferroelectric liquid crystal, the polymerizable liquid crystal 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. .

3. Common Electrode Substrate The common electrode substrate used in the present invention has a second substrate and a common electrode substrate having a common electrode formed on the second substrate. Among these, the common electrode substrate preferably has a second alignment film formed on the common electrode. In this case, a driving liquid crystal layer is formed between the fixed liquid crystal layer of the TFT substrate and the second alignment film of the common electrode substrate.

  Note that the second substrate and the common electrode can be the same as the first substrate and the pixel electrode of the TFT substrate, respectively, and thus description thereof is omitted here. Hereinafter, other configurations of the common electrode substrate will be described.

(1) Second alignment film The second alignment film used in the present invention is not particularly limited as long as the ferroelectric liquid crystal can be aligned. For example, a rubbing alignment film, A photo-alignment-treated photo-alignment film, an oblique deposition alignment film, or the like can be used. The rubbing alignment film, the photo-alignment alignment film, and the oblique deposition alignment film are the same as those described in the section of the alignment film for reactive liquid crystal of the TFT substrate. The description in is omitted.

(2) Preferred Embodiment In the present invention, the driving liquid crystal layer includes a ferroelectric liquid crystal, and the ferroelectric liquid crystal does not pass through the smectic A (SmA) phase in the temperature lowering process, and does not pass through the chiral smectic C (SmC ^* ). In the case of expressing the phase, the second alignment film is preferably a rubbing-treated alignment film, a photo-aligned photo-alignment film, or an oblique deposition alignment film. A ferroelectric liquid crystal that exhibits the SmC ^* phase without passing through the SmA phase is likely to generate two regions (referred to as a double domain) having different layer normal directions. Will be displayed. On the other hand, since the ferroelectric liquid crystal is sandwiched between the fixed liquid crystal layer and the second alignment film as described above, the occurrence of double domains can be suppressed and monodomain alignment can be obtained. Can do. This is considered to be due to the following reasons. That is, it is considered that the polar liquid surface interaction, which is the interaction between the ferroelectric liquid crystal, the surface of the fixed liquid crystal layer and the surface of the second alignment film, is different between the fixed liquid crystal layer and the second alignment film as described above. . Therefore, the fixed liquid crystal layer tends to have a relatively positive polarity between the fixed liquid crystal layer and the second alignment film, and the positive polarity of the spontaneous polarization of the ferroelectric liquid crystal is directed to the second alignment film side. By utilizing this tendency, the direction of spontaneous polarization of liquid crystal molecules can be controlled. Further, since the direction of spontaneous polarization of liquid crystal molecules can be controlled, the ferroelectric liquid crystal monolithic material does not generate a double domain peculiar to the ferroelectric liquid crystal that expresses the SmC ^* phase without passing through the SmA phase. Domain orientation can be obtained.

Further, the driving liquid crystal layer includes a ferroelectric liquid crystal, and the ferroelectric liquid crystal exhibits a chiral smectic C (SmC ^* ) phase without passing through the smectic A (SmA) phase in the temperature lowering process. In this case, it is also preferable that the common electrode is in direct contact with the driving liquid crystal layer. In this case, since the ferroelectric liquid crystal is sandwiched between the fixed liquid crystal layer of the TFT substrate and the common electrode of the common electrode substrate, generation of double domains can be suppressed and monodomain alignment can be obtained. Can do. The fixed liquid crystal layer and the common electrode are considered to have different polar surface interactions, which are the interactions between the ferroelectric liquid crystal, the surface of the fixed liquid crystal layer, and the surface of the common electrode. For this reason, the fixed liquid crystal layer tends to have a relatively positive polarity between the fixed liquid crystal layer and the common electrode, and the positive polarity of the spontaneous polarization of the ferroelectric liquid crystal tends to face the common electrode side. Can be used to control the direction of spontaneous polarization of liquid crystal molecules. Further, since the direction of spontaneous polarization of liquid crystal molecules can be controlled, the ferroelectric liquid crystal monolithic material does not generate a double domain peculiar to the ferroelectric liquid crystal that expresses the SmC ^* phase without passing through the SmA phase. Domain orientation can be obtained.

Further, in the case where the driving liquid crystal layer includes a ferroelectric liquid crystal, the ferroelectric liquid crystal exhibits a chiral smectic C (SmC ^* ) phase without passing through the smectic A (SmA) phase in the temperature lowering process. The common electrode substrate contains a second substrate, a common electrode formed on the second substrate, a photoisomerization reactive compound formed on the common electrode and having an azobenzene skeleton in the molecule; It is also preferable to have an unoriented treatment layer that has not been subjected to an orientation treatment. In this case, the ferroelectric liquid crystal is sandwiched between the fixed liquid crystal layer of the TFT substrate and the non-oriented processing layer of the common electrode substrate, so that the generation of double domains can be suppressed, and the monodomain alignment can be achieved. Obtainable. The fixed liquid crystal layer and the non-oriented treatment layer are considered to have different polar surface interactions, which are the interactions between the ferroelectric liquid crystal and the surfaces of the fixed liquid crystal layer and the non-oriented treatment layer. For this reason, the fixed liquid crystal layer tends to have a relatively positive polarity between the fixed liquid crystal layer and the non-oriented treatment layer, and the positive polarity of the spontaneous polarization of the ferroelectric liquid crystal is directed to the non-oriented treatment layer side. By utilizing this tendency, the direction of spontaneous polarization of liquid crystal molecules can be controlled. Further, since the direction of spontaneous polarization of liquid crystal molecules can be controlled, the ferroelectric liquid crystal monolithic material does not generate a double domain peculiar to the ferroelectric liquid crystal that expresses the SmC ^* phase without passing through the SmA phase. Domain orientation can be obtained.

  In addition, it can confirm that a non-orientation treatment layer is what has not been subjected to the orientation treatment by measuring the polarization ultraviolet-visible absorption spectrum of a non-orientation treatment layer. That is, using a UV-visible spectrophotometer (V7100: manufactured by JASCO Corporation), the non-oriented treatment layer is irradiated with polarized ultraviolet rays, and polarized ultraviolet / visible absorption spectra parallel and perpendicular to the polarization direction of the ultraviolet rays are obtained. taking measurement. If the ratio of the absorption peak of the spectrum in the vertical direction and the horizontal direction is 1.2 or less, it is assumed that the alignment treatment has not been performed.

  The ratio of the absorption peak of the spectrum in the vertical direction and the horizontal direction is preferably 1.2 or less, more preferably 1.1 or less. Depending on the method of applying the material when forming the unoriented layer, the unoriented layer may have a slight anisotropy. The lower limit of the ratio of absorption peaks is not particularly limited.

  Examples of the photoisomerization reactive compound having an azobenzene skeleton in the molecule include, for example, JP 2006-350322 A, JP 2006-323214 A, JP 2005-258429 A, and JP 2005-258428 A. Can be used.

  The thickness of the unoriented treatment layer 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 thickness of the non-oriented treatment layer is smaller than the above range, the non-oriented treatment layer may not be partially formed. Conversely, if the thickness of the non-oriented treatment layer is thicker than the above range, the transmittance is lowered.

  For example, JP 2006-350322 A, JP 2006-2006 A include a photoisomerization reactive compound having an azobenzene skeleton in the molecule and a method for forming an unoriented treatment layer that has not been subjected to photo-alignment treatment. In the method for forming a photo-alignment film described in Japanese Patent No. 323214, Japanese Patent Application Laid-Open No. 2005-258429, and Japanese Patent Application Laid-Open No. 2005-258428, the same applies except that light with controlled polarization is not irradiated.

4). Polarizing plate The liquid crystal display element of the present invention may have a polarizing plate outside the TFT substrate and the common electrode substrate. The polarizing plate is not particularly limited as long as it transmits only a specific direction in the wave of light, and a polarizing plate that is generally used as a polarizing plate of a liquid crystal display element can be used.

5). Method for Driving Liquid Crystal Display Element As a method for driving the liquid crystal display element of the present invention, a field sequential method is suitable. This is because it is not necessary to provide a color filter on the common electrode substrate, alignment is unnecessary, and the aperture ratio can be increased. In particular, when the driving liquid crystal layer includes a ferroelectric liquid crystal, the high-speed response of the ferroelectric liquid crystal can be used, so that one pixel is time-divided and a high-speed response is obtained in order to obtain good video display characteristics. A field sequential method that requires special characteristics is suitable.

  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.

The following examples illustrate the present invention in more detail.
[Example 1]
(Production of TFT substrate)
A substrate on which a TFT electrode layer (a TFT element having a thickness of 0.75 μm, a gate line having a thickness of 0.25 μm, a source line having a thickness of 0.2 m, an auxiliary capacitor having a thickness of 0.55 μm, a pixel electrode) is formed Got ready. The pixel size was 80 μm × 80 μm.
The substrate was thoroughly washed, and a resin black matrix resist (trade name: MCK-013-11S manufactured by Mitsubishi Chemical Corporation) was spin coated on the substrate, dried under reduced pressure, and prebaked at 100 ° 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. As a result, a light-shielding portion having a height of 0.4 μm was formed on the TFT element.
Next, after cleaning the substrate, a transparent resist (trade name, manufactured by NN780 JSR) was spin-coated on the substrate on which the light shielding portion was formed. 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. As a result, partition walls having a height of 1.45 μm were formed in stripes on the gate lines. At this time, stripe-shaped partition walls were formed so that the partition walls were positioned on the gate lines every 12 pixels.
Next, this substrate was washed and dried, and then a solution (made by Chisso Corporation) diluted with NBG-776 of rubbing alignment film material (trade name: PIA-5770-01A made by Chisso Corporation) to 50% was spin coated (1000 rpm) , 20 seconds), pre-baked at 100 ° C. for 15 minutes, and post-baked at 230 ° C. for 60 minutes. After the TFT substrate was cooled to room temperature, a rubbing alignment treatment was performed to form a rubbing film.
Subsequently, a 2.5 mass% solution of cyclopentanone in a polymerizable liquid crystal material (trade name: manufactured by ROF 3604 ROLIC) is spin-coated (1000 rpm, 20 seconds) on the rubbing film, and dried at 60 ° C. for 5 minutes. Under a nitrogen atmosphere, ultraviolet rays of 1000 mJ / cm ² were irradiated for polymerization to form an immobilized liquid crystal layer.

(Production of common electrode substrate)
The glass substrate on which the ITO electrode is formed is thoroughly washed, and 50% of this glass substrate is made of N-methyl-2-pyrrolidone of a photoisomerization reaction type photo-alignment film material (trade name: manufactured by LIA-03 DIC). The solution diluted to 1 was spin-coated (1000 rpm, 20 seconds), dried at 100 ° C. for 4 minutes, and then irradiated with linearly polarized ultraviolet rays of about 100 mJ / cm ² to perform alignment treatment to form a photo-alignment film.

(Production of liquid crystal display element)
Next, ferroelectric liquid crystal (manufactured by R2301 AZ Electronic Materials) was applied to the produced TFT substrate using an inkjet head heated to 100 ° C. Next, the produced common electrode substrate was adsorbed by an adsorption plate heated to 115 ° C. Next, the TFT substrate was adsorbed on a suction plate heated to 110 ° C. facing each other so that the alignment treatment direction with the common electrode substrate was parallel. Then, both substrates were brought into close contact with each other in a state where the vacuum chamber was evacuated to 100 Pa, and after applying a certain pressure, the inside of the vacuum chamber was returned to normal pressure. Thereafter, the ferroelectric liquid crystal was aligned by slowly cooling to room temperature to produce a liquid crystal display element.

(Evaluation)
When the alignment state of the ferroelectric liquid crystal was observed with a polarizing microscope for the manufactured liquid crystal display element, uniform alignment was obtained over the entire display region. In addition, light leakage due to alignment disorder was hardly observed in the gate line and source line portions. FIG. 5B shows a polarizing microscope photograph of the liquid crystal display element of Example 1.

[Example 2]
A liquid crystal display device was produced in the same manner as in Example 1 except that the solution concentration of the polymerizable liquid crystal material was changed to 1.0 mass% in the production of the TFT substrate. That is, the thickness of the fixed liquid crystal layer of Example 2 was made thinner than the thickness of the fixed liquid crystal layer of Example 1.
When the alignment state of the ferroelectric liquid crystal was observed with a polarizing microscope for the manufactured liquid crystal display element, uniform alignment was obtained over the entire display region. In addition, light leakage due to alignment disorder was hardly observed in the gate line and source line portions.

[Example 3]
In the production of the TFT substrate, a liquid crystal display element was produced in the same manner as in Example 1 except that the trade name: ROF 5101 (manufactured by ROLIC) was used as the polymerizable liquid crystal material.
When the alignment state of the ferroelectric liquid crystal was observed with a polarizing microscope with respect to the prepared liquid crystal display element, zigzag defects were observed in some places, but light leakage due to alignment disorder was hardly observed even in the gate line and source line portions.

[Comparative Example 1]
(Production of TFT substrate)
In the same manner as in Example 1, a light shielding portion and a stripe-shaped partition were formed. The substrate on which the light-shielding part and the barrier ribs were formed was washed, and diluted to 50% with N-methyl-2-pyrrolidone of a photoisomerization type photo-alignment film material (trade name: manufactured by LIA-03 DIC) on this substrate. The obtained solution was spin-coated (1000 rpm, 20 seconds), dried at 100 ° C. for 4 minutes, and then irradiated with linearly polarized ultraviolet rays of about 100 mJ / cm ² to perform an alignment treatment to form a photo-alignment film.
(Production of common electrode substrate)
The glass substrate on which the ITO electrode was formed was thoroughly washed, and a solution (manufactured by Chisso Corporation) diluted to 50% with NBG-776 of a rubbing alignment film material (trade name: PIA-5770-01A manufactured by Chisso Corporation) on the glass substrate. ) Was spin coated (1000 rpm, 20 seconds), pre-baked at 100 ° C. for 15 minutes, and post-baked at 230 ° C. for 60 minutes. After cooling the substrate to room temperature, a rubbing alignment treatment was performed to form a rubbing film. Subsequently, a 2.5 mass% solution of cyclopentanone in a polymerizable liquid crystal material (trade name: manufactured by ROF 3604 ROLIC) is spin-coated (1000 rpm, 20 seconds) on the rubbing film, and dried at 60 ° C. for 5 minutes. Under a nitrogen atmosphere, ultraviolet rays of 1000 mJ / cm ² were irradiated for polymerization to form an immobilized liquid crystal layer.
(Production of liquid crystal display element)
Next, in the same manner as in Example 1, a TFT substrate and a common electrode substrate were bonded together to produce a liquid crystal display element.
(Evaluation)
When the alignment state of the ferroelectric liquid crystal was observed with a polarizing microscope for the manufactured liquid crystal display element, uniform alignment was obtained in the entire display region, but light leakage due to alignment disorder was observed along the gate line and source line portions. It was seen. FIG. 5A shows a polarizing microscope photograph of the liquid crystal display element of Comparative Example 1.

[Comparative Example 2]
A liquid crystal display device was produced in the same manner as in Comparative Example 1 except that the photo-alignment film material (trade name: manufactured by LIA-03 DIC) was used as it was without being diluted in the production of the TFT substrate. That is, the thickness of the photo-alignment film of Comparative Example 2 was made larger than the thickness of the photo-alignment film of Comparative Example 1.
When the alignment state of the ferroelectric liquid crystal was observed with a polarizing microscope for the manufactured liquid crystal display element, uniform alignment was obtained in the entire display region, but light leakage due to alignment disorder was observed along the gate line and source line portions. It was seen.

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display element 11 ... TFT substrate 12 ... 1st substrate 13 ... Pixel electrode 14 ... Reactive liquid crystal aligning film 15 ... Fixed liquid crystal layer 16 ... Spacer 21 ... TFT element 22 ... Gate electrode 23 ... Gate insulating film 24 ... Semiconductor layer 25 ... Source electrode 26 ... Drain electrode 27 ... Light shielding part 31 ... Common electrode substrate 32 ... Second substrate 33 ... Common electrode 34 ... Second alignment film 41 ... Drive liquid crystal layer

Claims (8)

A first substrate, a TFT electrode layer formed on the first substrate and having a plurality of TFT elements and pixel electrodes connected to the TFT elements, and an alignment film for reactive liquid crystal formed on the TFT electrode layer And a TFT substrate having a fixed liquid crystal layer formed on the reactive liquid crystal alignment film and formed by fixing the reactive liquid crystal,
A common electrode substrate having a second substrate and a common electrode formed on the second substrate;
A driving liquid crystal layer formed between the fixed liquid crystal layer of the TFT substrate and the common electrode of the common electrode substrate.   The liquid crystal display element according to claim 1, wherein the TFT substrate has a light shielding part formed on the TFT element.   The liquid crystal display element according to claim 1, wherein the TFT substrate has a spacer formed on a non-pixel region of the TFT electrode layer.   4. The liquid crystal display element according to claim 1, wherein the driving liquid crystal layer includes a ferroelectric liquid crystal.   The common electrode substrate has a second alignment film formed on the common electrode, and the driving liquid crystal layer is formed between the fixed liquid crystal layer and the second alignment film. The liquid crystal display element in any one of Claim 1- Claim 4.   6. The liquid crystal display element according to claim 1, wherein the reactive liquid crystal exhibits a nematic phase.   The liquid crystal display element according to any one of claims 1 to 6, wherein the reactive liquid crystal contains a polymerizable liquid crystal monomer.   8. The liquid crystal display element according to claim 1, wherein the liquid crystal display element is driven by a field sequential method.