JPH08114804A - Liquid crystal display element and its production - Google Patents

Abstract

PURPOSE: To obtain the display element having liquid crystal oriented films capable of uniformly orienting liquid crystal molecules in a specified direction without making rubbing operation by providing these oriented films with first oriented films having striped ruggedness on the surfaces and second oriented films consisting of an org. compd. having the molecular axes unified in parallel with the groove direction of the ruggedness. CONSTITUTION: Respective substrates 1 are provided with transparent electrodes 2 on their liquid crystal 3 side and are formed with the first oriented films 4 having the striped ruggedness or the striped ruggedness and the saw tooth- shaped ruggedness in a direction perpendicular to this ruggedness on the surfaces of the transparent electrodes 2. Further, the first oriented films 4 are provided thereon with the second oriented films 5 consisting of the org. compd. unified in the molecular axes in parallel with the groove direction of the striped ruggedness. As a result, the orientation directions and pretilt angles of liquid crystals are controllable by the ruggedness formed at the first oriented films 4 and the liquid crystals are further strongly oriented in the main chain direction of the org. compds. constituting the second oriented films 5 by the interaction of the liquid crystal molecules and the molecules of the second oriented films.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device applied to, for example, a word processor, a laptop personal computer, a pocket television and the like, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Generally, a liquid crystal display device has a structure in which a liquid crystal is sandwiched between a pair of substrates each having a transparent electrode. The liquid crystal display device having such a structure is manufactured, for example, as follows. A transparent electrode made of ITO or the like is formed in a stripe shape on a transparent substrate made of glass or the like, a liquid crystal alignment film is formed thereon, and then two transparent substrates are opposed to each other so that the transparent electrodes are in a matrix shape, and a spacer is formed. A space is provided between the substrates to bond the peripheral portions of both substrates with an adhesive, and liquid crystal is vacuum-injected into the space to seal the injection port.

Polarizing plates are arranged so as to be orthogonal to each other on each of the front and back sides of the liquid crystal display device manufactured as described above, and the structure is such that a backlight is irradiated from one side.
The display is actually performed. The display uses the property that when a voltage is applied to the liquid crystal display element, the plane of polarization changes and the amount of transmitted light changes.

Here, in order to obtain a liquid crystal display device having a high contrast, it is indispensable to orient the injected liquid crystal molecules uniformly in a certain direction, and such a uniform orientation of the liquid crystal is caused by the alignment film used. Depends on.

A rubbing method is generally used as a method for producing an alignment film that affects the alignment characteristics. In this rubbing method, a polymer material such as polyimide or polyvinyl alcohol is spin-coated on a substrate on which an electrode is formed, and then the surface of the polymer film is kept constant while rotating a roller made of nylon rubbing cloth. This is a method of forming a liquid crystal alignment film by imparting strain anisotropy in the rubbing direction by rubbing in the direction, that is, rubbing treatment so that the long axis directions of the liquid crystal molecules are aligned in the rubbing direction.

[0006]

However, in the case of the rubbing method described above, a simple method of rubbing the surface of the polymer film with a cloth wound around a roller is widely used because of its good mass productivity and high reliability. Although this method is used industrially, it has the following drawbacks. That is, static electricity generated by rubbing the film surface with a cloth may cause electrostatic breakdown of the driving thin film transistor in the active matrix driving method in which the MOS-FET is incorporated in the liquid crystal display element. In addition, the residue of the rubbing cloth may adhere to the polymer film as dust, or the thickness of the substrate or the abrasion of the rubbing cloth or the residue of the rubbing cloth adheres to the roller to cause uneven rubbing strength. The orientation may be uneven.

Therefore, in order to solve the problems of the rubbing method, the following first to fourth methods, which are methods of forming an alignment film without rubbing, have been proposed.

In the first method, a monomolecular adsorption film of a silane coupling agent having a linear polymerizable group is irradiated with an energy beam while applying a magnetic field to crosslink the polymerizable group and fix the orientation. This is a method of controlling the pretilt angle of liquid crystal with a silane coupling agent (JP-A-4-356020).

The second method is a method of aligning a photopolymerizable liquid crystal monomer by irradiating it with ultraviolet rays while applying a magnetic field (JP-A-63-129323).

The third method is a method of controlling the alignment direction and pretilt angle of the liquid crystal by forming specific irregularities on the surface of the alignment film.

The fourth method is a method of forming specific irregularities on the surface of the photosensitive glass and applying a horizontal aligning agent or a vertical aligning agent on the surface (Japanese Patent Laid-Open No. 3-209220).

However, in the case of the above first to fourth methods, there are the following problems. In the case of the first method, the liquid crystal can be oriented in any direction by applying a magnetic field and crosslinking the polymerizable group, but the pretilt angle of the liquid crystal cannot be controlled arbitrarily.

In the case of the second method, since the liquid crystal monomer is aligned in the magnetic field application direction and photopolymerized, the liquid crystal can be aligned in any direction including the pretilt angle depending on the magnetic field application direction. However, when manufacturing a large-area display, there is a problem that the magnetic field generator becomes huge.

In the case of the third method, since the liquid crystal orientation is controlled only by the surface shape, the force that regulates the liquid crystal orientation direction shows a value that is one to two orders of magnitude weaker than that of the rubbing method. The orientation is likely to be disturbed by applying an electric field.

In the case of the fourth method, comparing the alignment regulating force due to the unevenness of the surface with the alignment regulating force of the horizontal aligning agent or the vertical aligning agent, the alignment regulating force of each aligning agent is stronger. Is not the unevenness of the surface, but is oriented in the alignment direction of the molecular long axis of each aligning agent. That is, it is difficult to align the liquid crystal in a specific direction because the molecular major axis direction of each aligning agent is not controlled.

The present invention has been made to solve the problems of the prior art, and a liquid crystal display having an alignment film for uniformly aligning liquid crystal molecules in a certain direction without performing a rubbing operation. An object is to provide an element and a manufacturing method thereof.

[0017]

In the liquid crystal display device of the present invention, a liquid crystal is sandwiched between a pair of substrates, and the transparent electrodes and the liquid crystal alignment film provided on the liquid crystal side of each substrate make the latter more than the former. In a liquid crystal display element arranged on the liquid crystal side, the liquid crystal alignment film is provided on the first alignment film having a stripe-shaped unevenness on its surface, and the groove direction of the stripe-shaped unevenness is provided on the first alignment film. And a second alignment film made of an organic compound whose molecular axes are aligned in parallel with the above, thereby achieving the above object.

In the liquid crystal display element of the present invention, the first
The alignment film has stripe-shaped irregularities on the surface,
It is possible to have a configuration having sawtooth-shaped irregularities in a direction perpendicular to the stripe-shaped irregularities.

In the liquid crystal display device of the present invention, the organic compound forming the second alignment film may be a photocurable compound containing a methacryloyl group, an acryloyl group or a cinnamoyl group.

In the method of manufacturing a liquid crystal display element of the present invention, the liquid crystal is sandwiched between a pair of substrates, and the transparent electrode and the liquid crystal alignment film provided on the liquid crystal side of each substrate bring the latter to the liquid crystal side more than the former. In the method for manufacturing the arranged liquid crystal display element, an alignment film material is formed on the surface of each substrate having a transparent electrode, and stripe-shaped unevenness or stripe-shaped unevenness and the unevenness are formed on the surface of the alignment film material. On the other hand, a step of forming a saw-toothed concavo-convex pattern in a substantially perpendicular direction to obtain a first alignment film, and applying a mixture of an alignment liquid crystal and a photocurable compound on the substrate on which the first alignment film is formed. , A step of forming a second alignment film by irradiating light and a pair of substrates on which a liquid crystal alignment film composed of the first and second alignment films is formed are opposed to each other, and liquid crystal is filled between the pair of opposed substrates. And the step of It is.

In the method of manufacturing a liquid crystal display element of the present invention, the liquid crystal is sandwiched between a pair of substrates, and the transparent electrode and the liquid crystal alignment film provided on the liquid crystal side of each substrate bring the latter to the liquid crystal side more than the former. In the method for manufacturing the arranged liquid crystal display element, an alignment film material is formed on the surface of each substrate having a transparent electrode, and stripe-shaped unevenness or stripe-shaped unevenness and the unevenness are formed on the surface of the alignment film material. On the other hand, a step of forming a saw-toothed concavo-convex pattern in a substantially right-angled direction to obtain a first alignment film, a spacer is interposed between the two substrates on which the first alignment film is formed, and the concavo-convex pattern is parallel. And make them face-to-face,
A step of injecting a mixture of an alignment liquid crystal and a photocurable compound between a pair of opposed substrates and irradiating light to form a second alignment film, and a liquid crystal alignment film composed of the first and second alignment films. And a step of facing a pair of substrates on which a substrate is formed with a spacer interposed therebetween and filling a liquid crystal between the pair of substrates facing each other, whereby the above object is achieved.

[0022]

In the manufacturing method of the present invention, the mixture of the alignment liquid crystal and the photocurable compound is applied on the substrate on which the first alignment film is formed. Alternatively, the substrates on which the first alignment film is formed are opposed to each other via a spacer, and the mixture is injected between the opposed substrates. As a result, the alignment liquid crystal is aligned with the long axis direction oriented toward the groove direction of the stripe-shaped unevenness formed on the surface of the first alignment film. On the other hand, the photocurable compound is also affected by the alignment of the alignment liquid crystal and exhibits similar alignment. Then, when the photocurable compound is irradiated with ultraviolet rays, the second alignment film is formed by binding while being aligned. In particular, when the first alignment film has sawtooth-shaped irregularities, the liquid crystal is aligned along the irregularities and exhibits a pretilt angle.

As a result, the alignment direction and pretilt angle of the liquid crystal can be controlled by the irregularities formed on the surface of the first alignment film. In addition, the liquid crystal can be more strongly aligned in the main chain direction of the organic compound forming the second alignment film by the interaction between the liquid crystal molecules and the molecules of the second alignment film.
That is, since the groove direction of the stripe-shaped unevenness and the main chain direction of the organic compound are parallel to each other, the interaction between the liquid crystal and the organic compound, that is, the alignment regulating force can be strengthened as compared with the liquid crystal alignment only by the surface shape. In addition, the pretilt angle can be controlled by the saw-toothed concavity and convexity.
As a result, the occurrence of defects such as disclination can be reduced.

Further, in the manufacturing method of the present invention, the second
A method of aligning the molecular axes of the alignment film is a method of aligning the alignment liquid crystal and the photocurable compound according to the shape of the first alignment film, and irradiating ultraviolet rays in that state to polymerize the alignment of the molecular axes. Therefore, it is not necessary to apply a magnetic field or an electric field for orientation, and a large-scale device is unnecessary.

[0025]

First, a stamp used in the present invention will be described. In this embodiment, a stamp that forms only stripe-shaped irregularities and a stamp that forms stripe-shaped irregularities and sawtooth-shaped irregularities in a direction substantially perpendicular to the irregularities are used. That is, two types of stamps having different surface shapes are used. Among them, for one type of stamp forming the stripe-shaped unevenness and the sawtooth-shaped unevenness, the one in which the inclination angle of the groove of the sawtooth-shaped unevenness is changed at two levels is used. That is, the case where a total of three stamps are used will be described as an example.

<Manufacture of Stamp> A method of manufacturing a stamp for forming stripe-shaped unevenness and sawtooth-shaped unevenness will be described. First, a blazed diffraction grating having a surface shape with a long sawtooth groove pitch is formed directly on a glass substrate,
A thick nickel plating is applied on the blazed diffraction grating, and this is peeled off to produce a first stamp. Further, before and after this, a second stamp is manufactured by a similar method using a diffraction grating having a striped surface shape and a short pitch.

Then, the first stamp is pressed against a thermoplastic resin film formed on another glass substrate with a pressing machine while being heated to transfer the surface shape.

Next, the second stamp is placed on the surface of the thermoplastic resin onto which the shape of the first stamp has been transferred so that the surface shape is at a right angle, and the surface shape is transferred by pressing with a pressing machine.

Next, a silicone resin (TS) is applied to the surface of the thermoplastic resin on which the two types of irregularities have been formed in this way.
E3032: made by Toshiba Silicone), about 70
Cure at 4 ° C for 4-5 hours. This finally produces a stamp.

In the present embodiment, as shown in FIG. 2, the stripe-shaped unevenness has a pitch P1 of 0.55 μm, a groove depth a of 0.1 μm, and a sawtooth-shaped unevenness pitch P2 of 1.1 μm.
m, the depth b of the groove is 0.1 μm, and the inclination angle of the sawtooth groove is 5
Conditions other than that the stamp A has a slightly weaker shape, the pitch P2 of the sawtooth unevenness is 1.7 μm, the depth b is 0.1 μm, and the inclination angle of the sawtooth groove is about 3 °. A stamp B having the same shape as that of FIG. 2 was produced.

A method of manufacturing a stamp having only stripe-shaped irregularities will be described below. A stamp is produced by pouring a silicone resin (TSE3032: made by Toshiba Silicone) directly on the surface of a diffraction grating having a striped surface and a short pitch of unevenness, and curing the resin at about 70 ° C. for 4 to 5 hours. In this example, as a stamp having only stripe-shaped irregularities, a stamp C having a pitch P1 of 0.55 μm and a groove depth b of 0.1 μm was manufactured.

The photocurable compound used in the present invention will be described below.

In this photocurable compound, the alignment controlling liquid crystal is aligned along the surface shape of the first alignment film, and the molecular axis of the photocurable compound is required to be aligned accordingly. It is desired that the length of the long axis of the compound is similar to that of the liquid crystal molecule. That is, the alignment regulating force is too weak to align the oligomer or polymer polymerized to some extent with the surface shape of the first alignment film. Further, regarding the polymerizability, a polymer which is polymerized and polymerized by irradiation with light is desirable, and a monomer containing at least two methacryloyl groups, acryloyl groups or cinnamoyl groups, that is, a compound of the structural formula (I) shown below is desirable.

[0034]

Embedded image

Here, X is a methacryloyl group, an acryloyl group or a cinnamoyl group. Y is oxygen or, -CH ₂ CH ₂ O- or -C ₃ H ₆ O-, etc. -RO of
-(R is a polymethylene group) and the like are possible, but basically both sides are methacryloyl groups, acryloyl groups or cinnamoyl groups, and the length of the major axis of the molecule is about the same as the alignment liquid crystal and compatible with the alignment control liquid crystal If it exists, the Y part is not particularly limited.

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 FIG. 1 is a sectional view showing a liquid crystal display element according to Example 1. This liquid crystal display element
A pair of substrates 1 and 1 are disposed so as to face each other, and the thickness of the internal space of the pair of substrates 1 and 1 is adjusted by a spacer 6 provided at a peripheral end portion between them. A liquid crystal 3 is provided in the internal space. Each substrate 1 is provided with a transparent electrode 2 on the liquid crystal 3 side, and on the transparent electrode 2, stripe-shaped irregularities on the surface or stripe-shaped irregularities and saw teeth in a direction substantially perpendicular to the irregularities. The first alignment film 4 having a concave-convex shape is formed. Further, on the first alignment film 4, a second alignment film 5 made of an organic compound whose molecular axes are aligned parallel to the groove direction of the stripe-shaped unevenness is provided.

Next, a method for manufacturing the liquid crystal display device will be described.

First, the transparent electrode 2 made of ITO whose surface is finely processed is formed on the substrate 1. A glass substrate is used as the substrate 1 and, if necessary, Si
It is also possible to use a material obtained by spin-coating an insulating film such as O ₂ using a spinner and performing heat treatment.

Then, the transparent electrode 2 is covered and the substrate 1 is covered.
For example, Semicofine SP-910 (manufactured by Toray Industries, Inc.) is spin-coated using a spinner to a film thickness of 800 angstrom. Then, it is dried at about 60 ° C. for 1 minute.

Next, a stamp A made of a silicone resin having a surface shape as shown in FIG.
It is pressed against the surface of the film made of -910 at a pressure of 200 g / cm ² . After that, the stamp A is peeled off by holding at 70 to 80 ° C. for about 30 minutes.

Next, heat treatment is performed at 350 ° C. for 1 hour to perform imidization. As a result, as shown in FIG.
The alignment film 4 is formed.

Next, the two substrates 1 on which the first alignment film 4 is formed are placed with a 12 μm thick temporary fixing spacer 9 therebetween.
And, facing so that the surface shape is opposite and parallel,
Make cells without pasting.

Next, in the internal space of the cell, the photocurable compound 8 having a methacryloyl group represented by the structural formula (II) prepared in advance is 5 wt% with respect to the alignment control liquid crystal 7.
Inject the mixture being added at the ratio of.

[0045]

Embedded image

The amount of the photocurable compound 8 added to the liquid crystal 7 in the above mixture is 3 to 10 in consideration of polymerizability and orientation.
Addition of about wt% is desirable. Further, in order to facilitate photopolymerization, bezophenone is preferably added as a photosensitizer at a ratio of about 1 wt% with respect to the photocurable compound. As the alignment controlling liquid crystal 7, a nematic liquid crystal “E-8” manufactured by Merck Ltd. was used.

Next, the mixture injected into the inner space of the cell is irradiated with ultraviolet rays for 90 seconds by an ultraviolet exposure device.

Next, the cell is peeled off, and the surface of the glass substrate 1 is washed with IPA to remove all of the alignment controlling liquid crystal 7 and the unreacted photocurable compound 8. In this way, the second alignment film 5 is formed.

Next, the second alignment film 5 was simultaneously formed on the second alignment film 5.
The glass substrates 1 are made to face each other with a spacer 6 having a thickness of 12 μm interposed therebetween, and their surface shapes are opposite and parallel to each other, and the glass substrates 1 are bonded to each other.

Next, the nematic liquid crystal 3 is injected between the two glass substrates 1 which are bonded together. Thereby, a liquid crystal display element was produced.

FIG. 4 shows a case where polarizing plates are provided on both sides of the liquid crystal display element (cell) manufactured as described above in a crossed Nicols state and the liquid crystal display element is rotated between the polarizing plates. It is a figure which shows the relationship between the rotation angle of FIG. As can be seen from this figure, uniform extinction is obtained every 90 °. Further, the orientation shows almost the same value as that of the polyimide rubbing film when compared with the transmittance at the extinction position. Further, when the pretilt angle was measured by the magnetic field applied capacity, the result was about 5 °. This indicates that the liquid crystal molecules are aligned along the inclination of the sawtooth groove because the inclination angle of the sawtooth groove of the first alignment film 4 is slightly less than 5 °. That is, the second
In the structure of the alignment film 5, a polymer formed by irradiation of a photocurable compound with ultraviolet rays has its major axis oriented in the groove direction of the stripe-shaped unevenness with respect to the substrate and is inclined along the surface of the sawtooth-shaped unevenness. Is considered to have.

<Second Embodiment> The second embodiment will be described. In this Example 2, the first alignment film was formed instead of forming the second alignment film by injecting between the pair of opposed substrates after facing the substrates on which the first alignment film was formed. This is a case where the second alignment film is directly formed on the first alignment film of the substrate.

First, the first alignment film is formed on the substrate by the method of the first embodiment.

Next, 5 wt% of the photocurable compound 8 having a methacryloyl group represented by the structural formula (II) prepared in advance on the first alignment film is applied to the alignment control liquid crystal 7.
The mixture, which is added in the proportion of%, is spin-coated using a spinner.

Next, as shown in FIG. 5, the mixture is irradiated with ultraviolet rays for 90 seconds by an ultraviolet exposure device.

Next, the surface of the glass substrate 1 is washed with IPA to remove the entire alignment controlling liquid crystal 7 and the unreacted photocurable compound 8. Thereby, the second alignment film is formed.

Thereafter, a liquid crystal display device is manufactured by using the same materials and processes as those in the first embodiment.

In the liquid crystal display device manufactured as described above, it was found that the liquid crystal orientation was uniform in the stripe-shaped uneven direction and the pretilt angle was 5 °.

<Embodiment 3> In this embodiment, the stamp B is used.

First, the stamp B is used in place of the stamp A on the two glass substrates, and the first and second alignment films are formed in the same manner as in Example 1.

Next, two glass substrates were interposed with a spherical spacer having a diameter of 5 μm interposed therebetween, and the surface shapes of both substrates were 90 °.
Face each other in a rotated state and bond them together.

Next, when viewed from one substrate side, a nematic liquid crystal added with cholesteric liquid crystal that rotates counterclockwise is injected between a pair of opposing substrates. Thus, the TN liquid crystal display element of this example was manufactured.

FIG. 6 shows the results of measuring the transmittance by arranging polarizing plates in crossed Nicols on both sides of this liquid crystal display element and applying a rectangular wave of 60 Hz to the liquid crystal display element while changing the voltage. FIG. Apply voltage (V) on the horizontal axis,
The vertical axis shows the transmittance (%). As can be seen from FIG. 6, the liquid crystal display device of the present example provided substantially the same voltage-transmittance characteristic as the conventional TN liquid crystal display device using the rubbing polyimide alignment film.

<Embodiment 4> In this embodiment, a ferroelectric liquid crystal is used.

In this example, after the first and second alignment films were formed in the same manner as in Example 1, they were bonded so that their surface shapes would be parallel via a spherical spacer having a diameter of 1.4 μm. A liquid crystal display device was produced under the same conditions as in Example 1 except that the ferroelectric liquid crystal was injected.

The produced liquid crystal display element showed good orientation and bistability equivalent to those of a conventional liquid crystal display element using a rubbing polyimide orientation film.

<Embodiment 5> In this embodiment, the material and composition of the photocurable compound used for forming the second alignment film are different from those in Embodiment 1.

In this example, as the photocurable compound used for forming the second alignment film, a photocurable compound having a cinnamoyl group represented by the structural formula (III) was used, and the photocurable compound was used. Is 0.2w for liquid crystal for alignment
A liquid crystal display device was produced under the same conditions as in Example 1 except that the addition was made in the proportion of t%.

Regarding the manufactured liquid crystal display element, it was found that the liquid crystal orientation was uniform in the direction of stripe unevenness and had a pretilt angle of 5 °.

[0070]

Embedded image

<Embodiment 6> In this embodiment, only the material of the photocurable compound used for forming the second alignment film is different from that of the third embodiment.

In this example, as the photocurable compound used for forming the second alignment film, the photocurable compound having a cinnamoyl group represented by the structural formula (III) was used, and the photocurable compound of Example 3 was used. A TN liquid crystal display device was produced under the same conditions.

The liquid crystal display device thus produced was measured in the same manner as in Example 3. As shown in FIG. 6, the voltage-transmission was almost the same as that of a conventional TN liquid crystal display device using a rubbing polyimide alignment film. The rate characteristic was obtained.

<Embodiment 7> In this embodiment, the use of the stamp B and the material and composition of the photocurable compound used for forming the second alignment film are different from those of the first embodiment.

In this example, the stamp B was used for forming the first alignment film, and the photocurable compound used for forming the second alignment film had an acryloyl group represented by the structural formula (IV). Using a photocurable compound,
A liquid crystal display device was manufactured under the same conditions as in Example 1 except that the photocurable compound was added at a ratio of 4 wt% with respect to the alignment liquid crystal.

Regarding the manufactured liquid crystal display element, it was found that the liquid crystal orientation was uniform in the stripe-shaped uneven direction and had a pretilt angle of 3.2 °.

[0077]

[Chemical 4]

<Embodiment 8> This embodiment is different from Embodiment 1 only in the use of the stamp C.

In this example, a liquid crystal display element was manufactured under the same conditions as in Example 1 except that the stamp C was used for forming the first alignment film.

Regarding the manufactured liquid crystal display element, it was found that the liquid crystal orientation was uniform in the stripe-shaped uneven direction and the pretilt angle was 0 °.

<Comparative Example> A comparative example of the present invention will be described.

In this comparative example, a TN liquid crystal display element was produced in the same manner as in Example 3 except that the step of producing the second alignment film was not performed. Then, polarizing plates were arranged on both sides of the liquid crystal display element in a crossed Nicol manner.

With respect to the liquid crystal display device of this comparative example, the disorder of the liquid crystal alignment was observed by applying a slight pressure to the surface of the glass substrate. When the same experiment was performed on the liquid crystal display device of Example 3, it was necessary to apply a pressure about three times stronger in order to cause the same degree of disorder in the liquid crystal alignment.

[0084]

As described in detail above, according to the present invention, the alignment direction of the liquid crystal is controlled by the unevenness formed on the surface of the first alignment film, and the liquid crystal molecules and the second alignment film molecules are controlled. The liquid crystal is more strongly aligned in the main chain direction of the polymer forming the second alignment film by the interaction with. That is, since the groove direction of the stripe-shaped unevenness and the main chain direction of the polymer are parallel to each other, it is possible to strengthen the alignment regulating force as compared with the liquid crystal alignment only by the surface shape, and thereby, in that direction. The liquid crystal can be strongly aligned. In particular, in the case of an alignment film having sawtooth-shaped irregularities, the pretilt angle can be controlled. As a result, the occurrence of defects such as disclination can be reduced.

Further, in the case of the manufacturing method of the present invention, the method of aligning the molecular axes of the second alignment film is such that the alignment liquid crystal and the photocurable compound are aligned according to the shape of the first alignment film and the molecules are irradiated by ultraviolet irradiation. Since it is a method of aligning the axes and polymerizing,
It is possible to omit applying a magnetic field applying device or applying an electric field.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a liquid crystal display element according to a first embodiment.

FIG. 2 is a perspective view showing a stamp used for producing a surface shape of a first alignment film in the present invention.

FIG. 3 is a cross-sectional view used for explaining the content of forming a second alignment film in a state where a pair of substrates are once placed in a facing arrangement (cells) in the present invention.

FIG. 4 shows polarizing plates arranged on both sides of the liquid crystal display device of Example 1 in a crossed Nicols state, and changes in transmittance when the liquid crystal display device is rotated between the polarizing plates and a polyimide rubbing film are used. It is a figure which shows the transmittance | permeability change at the same time regarding a liquid crystal display element.

FIG. 5 is a cross-sectional view used for explaining the content of forming a second alignment film without arranging a pair of substrates facing each other (cell) in the present invention.

FIG. 6 is a diagram showing voltage-transmittance characteristics of a TN liquid crystal display device of Examples 3 and 6 and a TN liquid crystal display device using a rubbing polyimide alignment film.

[Explanation of symbols]

 1 Glass Substrate 2 Transparent Electrode 3 Display Liquid Crystal 4 First Alignment Film 5 Second Alignment Film 6 Spacer 7 Alignment Control Liquid Crystal 8 Photocurable Compound 9 Temporary Fixing Spacer

Claims (4)

[Claims] 1. A liquid crystal display device in which a liquid crystal is sandwiched between a pair of substrates, and a transparent electrode and a liquid crystal alignment film provided on the liquid crystal side of each substrate arrange the latter on the liquid crystal side of the former, The liquid crystal alignment film is composed of a first alignment film having stripe-shaped irregularities on the surface, and an organic compound provided on the first alignment film and having molecular axes aligned parallel to the groove direction of the stripe-shaped irregularities. A liquid crystal display device comprising a second alignment film. 2. The liquid crystal display element according to claim 1, wherein the first alignment film has stripe-shaped irregularities on its surface, and has sawtooth-shaped irregularities in a direction orthogonal to the stripe-shaped irregularities. 3. A method of manufacturing a liquid crystal display device, wherein a liquid crystal is sandwiched between a pair of substrates, and a transparent electrode and a liquid crystal alignment film provided on the liquid crystal side of each substrate are arranged such that the latter is arranged on the liquid crystal side rather than the former. In, an alignment film material is formed on the surface of each substrate having a transparent electrode, and stripe-shaped unevenness or
A step of forming stripe-shaped unevenness and sawtooth-shaped unevenness in a direction substantially perpendicular to the unevenness to obtain a first alignment film, and a liquid crystal for alignment and photocuring on the substrate on which the first alignment film is formed. Of a mixture of the organic compound and a step of forming a second alignment film by irradiating with light, and a pair of substrates having a liquid crystal alignment film formed of the first and second alignment films facing each other A method for manufacturing a liquid crystal display device, the method including filling a liquid crystal between a pair of substrates. 4. A method of manufacturing a liquid crystal display device, wherein a liquid crystal is sandwiched between a pair of substrates, and a transparent electrode and a liquid crystal alignment film provided on the liquid crystal side of each substrate are arranged such that the latter is closer to the liquid crystal than the former. In, an alignment film material is formed on the surface of each substrate having a transparent electrode, and stripe-shaped unevenness or
A step of forming stripe-shaped unevenness and sawtooth-shaped unevenness in a direction substantially perpendicular to the unevenness to obtain a first alignment film; and a spacer between the two substrates on which the first alignment film is formed. A second alignment film is formed by interposing and interposing the concavities and convexities in parallel and in opposite directions, injecting a mixture of an alignment liquid crystal and a photocurable compound between a pair of opposed substrates, and irradiating with light. And a step of facing a pair of substrates on which a liquid crystal alignment film composed of the first and second alignment films is formed with a spacer interposed therebetween, and filling a liquid crystal between the pair of facing substrates. A method of manufacturing a liquid crystal display device including the same.