JPH07104259A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To provide a production method of a liquid crystal display element by which display quality is improved and phase separation to produce a liquid crystal region and a polymer material region in each picture element can easily be performed. CONSTITUTION:Laser light 20 converted into a linear beam is made to irradiate a linear nonpicture part 22 on the most end of a liquid crystal cell 19 for 5min. Then the beam is made to irradiate in the same way the next nonpicture part 22 for 5min. Thereby, a thermosetting resin in the area in a mixture 18 corresponding to the nonpicture element part 22 is hardened to form polymer walls 24. This procedure is successively performed for all nonpicture element parts 22 parallel in one direction. Then the same procedure is carried out for all nonpicture element parts 25 parallel to the direction perpendicular to the first direction to harden the thermosetting resin. By this method, the porous polymer walls 24 can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a liquid crystal display device in which a liquid crystal region is divided by polymer walls made of a polymer material. And the polymer material is TN (Tw
isted Nematic), STN (Surper Twisted Nemati)
c), ECB (Electrically Conrtoled Birefringenc
e), a conventional mode such as FLC (Ferroelectric Liquid Crystal), or a method for manufacturing a liquid crystal display element in a mode in which a liquid crystal region (liquid crystal domain) is radially aligned within a pixel. Further, the present invention can also be applied to a method of manufacturing a liquid crystal display element in a display mode in which light scattering occurring at an interface between a liquid crystal droplet and the polymer wall is used for display.

[0002]

2. Description of the Related Art Currently, as a display element using liquid crystal,
Liquid crystal display devices of many modes are used. For example, a TN (Twisted Nematic) type using a nematic liquid crystal as a display element utilizing the electro-optical effect, an STN
(Surper Twisted Nematic) type has been put to practical use. Ferroelectric liquid crystal (FLC)
Liquid crystal display devices using idCrystal) have also been proposed.
These require a polarizing plate, and require an alignment treatment for the alignment film on the substrate. on the other hand,
As a liquid crystal display device that does not require a polarizing plate and uses liquid crystal scattering for display, a dynamic scattering (DS) effect and a phase transition (P
C) There is a liquid crystal display element utilizing the effect.

Recently, as a liquid crystal display element which does not require a polarizing plate and does not require an alignment treatment, a liquid crystal display element which utilizes a birefringence of liquid crystal and electrically controls a transparent or cloudy state. Is proposed. This liquid crystal display device basically displays a transparent state by matching the ordinary refractive index of liquid crystal molecules with the refractive index of a supporting medium (polymer) when a voltage is applied to align the liquid crystals, and no voltage is applied. At the time of addition, display is performed by utilizing the light scattering state due to the disorder of the alignment of the liquid crystal molecules.

As another prior art, Japanese Patent Publication No. 61-502
No. 128, etc., a method of precipitating a liquid crystal locally in the resin by mixing the liquid crystal and a photo- or thermosetting resin and polymerizing the resin to form a liquid crystal droplet in the resin by phase separation. It is disclosed.

A method of limiting the display area of a display element using a photomask is disclosed in Japanese Patent Laid-Open No. 2-153318. In this prior art, the shape of each liquid crystal drop is not controlled by a photomask, but a transparent portion that has been cured while applying a voltage between electrodes and an uncured portion are separated,
After removing the photomask, the uncured portion is cured to form a scattering portion. After the display element is formed, by applying an electric field to the liquid crystal layer, the portion scattered in the pattern of the photomask becomes transparent and the entire display element becomes transparent.
Basically, it considers a single picture element.

In a liquid crystal device using a ferroelectric liquid crystal, SmC ^* (smectic C ^* ) is used to develop spontaneous polarization.
Since the phase is used and the regularity is closer to that of a crystal than the nematic phase, it is a problem that the impact resistance is weak. In order to solve this problem, it has been considered to disperse the ferroelectric liquid crystal in a polymer, but it is difficult to perform the alignment treatment in the polymer and it has not been put into practical use. As a method of aligning the ferroelectric liquid crystal in the polymer,
A method in which a ferroelectric liquid crystal is dispersed in a polymer, processed into a film, and then stretched in one direction to orient the liquid crystal is disclosed in JP-A-63-2647241 to 26472.
42.

However, in this method, many interfaces between the liquid crystal and the polymer exist in one picture element, and the incident linearly polarized light is scattered to depolarize a part of the light. The black level of the display element is lowered and the contrast is lowered. This problem is caused by the mode (TN, S
The same applies to TE, ECB, etc.). Furthermore, F
For the purpose of improving the impact resistance of LC, a method in which a polymer wall is formed on an alignment-treated substrate material by using photolithography to form a display element and then a liquid crystal material is injected between the substrates is a special method. KAISHO 59-201021, JP-A-3-192
334. However, this method cannot create an independent liquid crystal region for each picture element, and
It was difficult to strictly control the cell thickness, which is the liquid crystal layer thickness. In addition, in the phase separation method by light irradiation,
Moreover, there is a problem that it is difficult to produce a liquid crystal display device with a uniform cell thickness.

[0008] Recently, using these techniques, T
For the purpose of improving the viewing angle characteristics of an N-TFT (thin film transistor element) liquid crystal display element, a control element for controlling the scattering state-transparent state of liquid crystal is disclosed in JP-A-4-338923 and JP-A-4-212928. It is disclosed that the viewing angle characteristics are improved by arranging the polarizing plates between orthogonal polarizing plates. However, in the liquid crystal display element, display is performed by depolarizing polarized light due to scattering, and in principle, it is a limit to secure 50% brightness of the TN type liquid crystal display element, and an actual report ( Japan Display
'92 S-17, pp631), the brightness is T
It is reported to be 1/3 of N.

FIG. 12 is a sectional view of a conventional liquid crystal display element 1. In the conventional liquid crystal display element 1, a display electrode and an alignment film (not shown) are formed on a pair of glass substrates 2 and 3, respectively, and the alignment film is subjected to alignment treatment such as rubbing along one direction. . Liquid crystal is injected between these glass substrates 2 and 3 to form a liquid crystal layer 4. A drive voltage is applied by the drive circuit 5 to the display electrodes of each of the glass substrates 2 and 3 of the liquid crystal display device having such a configuration to drive the display.

FIG. 12 (1) is a diagram showing a halftone display state, and FIG. 12 (2) is a diagram showing a display state. In the case of such a liquid crystal display element 1, the liquid crystal molecules 6 are aligned parallel to the surfaces of the glass substrates 2 and 3 in the state where no drive voltage is applied. When a drive voltage is applied to the display electrodes, the liquid crystal molecules 6 gradually rise, and as shown in FIG.
As shown in FIG. 12, the display state of FIG. 12B is reached through the halftone display state in which the liquid crystal molecules 6 are tilted in the same direction. Here, in the halftone display state, when the liquid crystal display element 1 is viewed from the arrow A direction and the arrow B direction, which are relatively angled from the normal line direction of the liquid crystal display element 1, The apparent refractive index anisotropy Δn differs depending on the viewing direction. Therefore, the contrast differs depending on the viewing direction of the liquid crystal display element 1, and the black and white display may be inverted, which causes a problem. Further, when performing color display, there is a problem that the color tone differs depending on the viewing direction of the liquid crystal display element 1.

There are the following other conventional techniques for solving such a problem. Japanese Patent Laid-Open No. 5-27242,
By disturbing the regular arrangement of the liquid crystal molecules in the TN liquid crystal display element with a substantially mesh-like composition made of a polymer material (hereinafter, also referred to as a polymer matrix), the alignment state of the liquid crystal is randomized for each domain. Therefore, a method for improving the viewing angle characteristic is disclosed. However, this method cannot accurately limit the position of the liquid crystal region to be arranged for each picture element. Therefore, in a liquid crystal display device having a plurality of picture elements, a liquid crystal region cannot be arranged for each picture element, and there is a problem that the light transmittance of the liquid crystal display element is low. Furthermore, when the liquid crystal domains are randomly arranged, no extreme deterioration of the viewing angle characteristics such as black and white or inversion phenomenon in which the color tone is inverted is observed depending on the viewing angle. When the light transmittance is measured at an angle from the vertical direction, several percent of light leakage is observed. Therefore, there is a problem that the contrast at the time of display is low.

[0012]

As described above, any of the conventional techniques has a problem that the display quality is low, such as a low display contrast and a low brightness of a display image.

The present invention has been made to solve such a problem, and is a liquid crystal display device having a liquid crystal region divided by a polymer, a liquid crystal display device using a ferroelectric liquid crystal, or a light scattering type. In the liquid crystal display element of, the ratio of the liquid crystal region in the picture element to the polymer material is increased,
Manufacture of a liquid crystal display device in which contrast at the time of display and brightness of a display image are improved to improve display quality, and phase separation for forming a liquid crystal region and a polymer material region for each pixel can be easily performed. It is intended to provide a way.

[0014]

In order to solve the above-mentioned problems, the present inventors apply a heat pattern having a partial strength or a heat pattern and light in combination to cause polymerization phase separation. As a result, the present invention has been made through intensive studies on a method for producing a liquid crystal display element in which a liquid crystal region partitioned into a polymer material is selectively formed, and liquid crystal domains in the liquid crystal region have a radial or random alignment structure. did.

That is, according to the method of manufacturing a liquid crystal display element of the present invention, at least one of a pair of transparent substrates is provided with
An injection step of injecting a mixture of a liquid crystal material, a polymerizable resin composition and a polymerization initiator, and an application step of applying heat having a locally strong and weak pattern to the mixture, or applying heat and light in combination. By including the applying step, the polymerizable resin composition in the mixture is polymerized to phase-separate the liquid crystal material and the polymerizable resin composition, so that liquid crystal regions separated by the polymer material are formed. Therefore, the above object is achieved.

In the present invention, the application of heat is performed by the heat effect of a heat beam or the heat effect of a coherent light beam, and the polymerization of the polymerizable resin composition and the phase separation are performed in the mixture. It may be advanced.

In the present invention, the application of heat may be performed by irradiating the heat of the heat beam or the coherent light beam in a line-sequential manner.

In the present invention, the application of heat may be performed by irradiating a heat beam or a coherent light beam in a dot-sequential manner.

In the present invention, the application of the heat to the pair of substrates in which the black mask made of the light-shielding material is formed on at least one of the substrates is generated by high-frequency induction heating of the black mask. Heat may be used.

In the present invention, the black mask may be made of a magnetic material such as cobalt nickel.

In the present invention, the black mask may be made of resin mixed with magnetic particles.

In the present invention, the resin may be an acrylic resin or a polyimide resin.

[0023]

The present invention will be described in more detail below.

According to the present invention, a liquid crystal is applied to each pixel by applying a heat pattern having partial strength or a physical stimulation pattern using both heat and light to a uniform mixture of liquid crystal and a photocurable resin. The present invention relates to a method for manufacturing a liquid crystal display element that efficiently causes phase separation that creates a region and a region of a polymer material. In the present invention, as a first method regarding the specific method for producing the liquid crystal display device, a heat beam containing these laser beams is made into a single linear shape by a beam expander, and a high temperature is obtained from the most end side of the substrate. There is a method of performing a line scan only on the portion where the molecule is to be cured. As a second method, there is a method in which a point scan of only the portion where the polymer is desired to be cured is scanned from the most end side of the substrate with a laser. A third method is to heat a black mask having an arrangement pattern of light-shielding areas corresponding to the arrangement of picture elements by high frequency induction heating, and locally apply heat to the polymer in the portion overlapping with the black mask. The method of hardening is mentioned.

According to the above-mentioned principle of high frequency induction heating, when a high frequency magnetic field is applied to a black mask formed of a material containing at least a magnetic material, hysteresis loss and Joule heat due to eddy current are generated in the magnetic portion of the black mask. As a result, the temperature of the black mask is raised, and the portion of the polymer material that is in contact with the black mask is heated. In a liquid crystal display element in which a black mask is formed on the counter electrode of a liquid crystal display element or on an active matrix element such as a TFT, the black mask is in direct contact with the mixture of the polymerizable resin and the liquid crystal. The heat
It is directly transferred to the mixture of the polymerizable resin and the liquid crystal, and heating with good heat transfer efficiency can be performed. Further, according to such a heat application method of the present invention, in order to form a heat pattern, a new black mask is provided in addition to the black mask already provided so as not to cover the pixel region from the glass substrate. There is no need to attach it to.

Therefore, the positional deviation from the picture element region which occurs when the new black mask is attached to the glass substrate is eliminated. Further, since the step of attaching the black mask is newly unnecessary, the manufacturing yield is improved and the manufacturing cost is reduced. Further, the heating temperature can be set to a desired temperature by appropriately adjusting the number of coils N, the coil current I, and the frequency f. Furthermore, since heating by high frequency induction occurs in a short time, the manufacturing time can be significantly shortened, and the manufacturing efficiency can be improved and the manufacturing cost can be reduced.

By selecting these methods, the curing point (reaction point) of the polymer material can be appropriately limited, and the liquid crystal component is mixed into the polymer region, or conversely, the liquid crystal component. There is an advantage that the mixing of the polymer component can be suppressed.

The liquid crystal display device produced by the method of the present invention has a structure in which liquid crystal domains are radially or randomly aligned in the liquid crystal region. As a result, when the drive voltage is applied, the rising directions of the liquid crystal molecules are oriented in almost all directions, so that the viewing angle characteristics are improved.
That is, when a voltage is applied, the liquid crystal molecules are tilted toward each polymer wall due to the interaction between the liquid crystal molecules and the polymer wall made of a polymer material.
The liquid crystal display element has almost the same state at any viewing angle, and the viewing angle characteristics of the liquid crystal display element are improved.

[0029]

EXAMPLES Examples of the present invention will be shown below.
It is not limited to this.

(Embodiment 1) FIG. 1 is a perspective view illustrating a manufacturing process of a liquid crystal display element 11 according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating the manufacturing process. In the present embodiment, the liquid crystal display element 11 is manufactured by the following manufacturing process. Plural strip electrodes made of ITO (mixture of indium oxide and tin oxide, film thickness 50 nm) on two glass substrates 12 and 13 made of flint glass (manufactured by Nippon Sheet Glass Co., Ltd., plate thickness 1.1 mm, 300 mm square). (Electrode width 200 μm, electrode gap 50 μm, number of electrodes 100
0 × 1000) 14 and 15 are formed respectively. Polyimide (SE-150: NISSAN CHEMICAL CO., LTD.), Which is an alignment film paint, is applied to the pair of glass substrates 12 and 13 by spin coating, heat-cured, and rubbed in one direction with a nylon cloth. Then, the alignment films 16 and 17 were formed.

Two substrates 12, 1 which have been subjected to the above-mentioned orientation treatment
3 are combined so that the respective strip electrodes 14 and 15 are orthogonal to each other, and for example, a spacer having a diameter of 6 μm, such as spherical, cylindrical, or fibrous, is used to uniformly maintain the cell thickness, which is the distance between the alignment films 16 and 17. The peripheral portion was sealed with the sealing material 23 to form a display cell. Next, as a thermopolymerizable resin, an aliphatic epoxy resin Denacol EX-314 (manufactured by Nagase Kasei Co., Ltd.) 0.12 g, a curing accelerator Epomic Q-610 (manufactured by Mitsui Petrochemical Co., Ltd.) 0.006 g, and a liquid crystal material. As a mixture, 0.75 g of a mixture of ZLI-3700-000 (manufactured by Merck & Co., Inc.) with 0.3% by weight of CN (cholesteric nonanate) and a liquid crystal material was uniformly mixed, and then the mixture was added to the display cell prepared. Liquid crystal cell 19 was formed by injecting 18.

After that, the He--Cd laser light (hereinafter, laser light) 20 used as a laser heat beam is converted into a line shape by the beam expander 21 with respect to the liquid crystal cell 19, as shown in FIG. The line-shaped converted laser light 20 was irradiated for 5 minutes to the line-shaped non-picture element portion 22 at the end of the liquid crystal cell 19, and the next non-picture element portion 22 was similarly irradiated for 5 minutes. . Thus, the thermosetting resin in the portion corresponding to each non-picture element portion 22 in the mixture 18 was cured to form the polymer wall 24.

This series of operations is sequentially performed on all the non-picture element portions 22 parallel to one direction, and then on all the non-picture element portions 25 parallel to the other direction perpendicular to the one direction. Then, the thermosetting resin was cured. In this way, the polymer wall 24, which is a porous body, was formed between the glass substrates 12 and 13 in a substantially lattice pattern. Further, it was confirmed that the liquid crystal region 26 was formed by surrounding the liquid crystal for each picture element by the polymer wall 24 having a lattice shape.

The cross section of the formed polymer wall 24 of the porous body was observed with a SEM (scanning electron microscope) as follows. First, the liquid crystal display element 11 is divided, and the glass substrates 12 and 13 are separated from each other in liquid nitrogen.
The liquid crystal material was washed off with acetone from the surfaces of 2 and 13.
The horizontal cross section of the polymer wall 24 remaining after that was observed.
According to this, the polymer walls 24 having the same regularity as the strip electrodes 14 and 15, that is, the same regularity as the picture element and the same size as the picture element are arranged uniformly. It was confirmed.

The contrast, which is one of the electro-optical characteristics of the produced liquid crystal display element 11, was 40. For the measurement of the contrast, a method in which light is transmitted through the liquid crystal display element 11 for measurement is adopted. The contrast is expressed by the ratio between the light transmittance when no voltage is applied and the light transmittance when a saturation voltage is applied. Further, no display unevenness was observed when the created liquid crystal display element 11 was leaned against a wall or the like. The display unevenness at the time of this leaning is the viewing angle dependence of the liquid crystal display element whose display contrast differs depending on the viewing angle,
It is caused by roughness on the surface of the liquid crystal display element or display unevenness due to black-and-white inversion of the display.

In the liquid crystal display element 11 produced by the manufacturing method of this embodiment, it was confirmed that the liquid crystal domains in each liquid crystal region 26 had a structure in which the liquid crystal domains were radially or randomly aligned.

FIG. 3 (1) is a diagram showing a halftone display state, and FIG. 3 (2) is a diagram showing a display state. In the case of the liquid crystal display element 11 of the present embodiment, the liquid crystal molecules 27 in the liquid crystal region 26 are aligned parallel to the surfaces of the glass substrates 12 and 13 when the drive voltage is not applied. When a drive voltage is applied to the display electrodes by the drive circuit 28, the liquid crystal molecules 27 reach the display state of FIG. 3 (2) through the halftone display state of FIG. 3 (1) inclining in the same direction. .
Here, when a driving voltage is applied, the liquid crystal molecules 27 gradually rise, and in the halftone display state, as shown in FIG.
As shown in (1), when the saturation voltage is applied, the liquid crystal molecules 2
Due to the interaction between 7 and the polymer wall 24, the liquid crystal molecules 27 incline toward the polymer wall 24 in each direction. As a result, the apparent refractive index of the liquid crystal molecules 27 becomes substantially the same at each position in the direction A and the direction B. As a result, when the drive voltage is applied, the rising directions of the liquid crystal molecules are oriented in almost all directions, so that the viewing angle characteristics are improved.

Therefore, according to this embodiment, the liquid crystal display element 11 having a structure in which the liquid crystal domains in the liquid crystal region 26 are radially or randomly aligned can be prepared.

Further, among the electro-optical characteristics of the produced liquid crystal display element 11, the viewing angle characteristics are shown in FIG. FIG. 4 is a graph obtained by measuring the relationship between the applied voltage and the light transmittance while changing the viewing angle. Regarding the light transmittance, a liquid crystal display element 11 is provided with a black mask with a color filter that transmits light only in a pixel region and blocks light between each pixel, and two polarizing plates are provided. The liquid crystal display element 11 was laminated so that the planes of polarization of the two were parallel to each other, and the state in which light passed through such a liquid crystal display element was measured with a light transmittance of 100%. Further, the measurement direction is measured from the normal direction of the liquid crystal display element 11 and from four directions of the conical surface inclined by 40 ° from the normal direction, which are 45 ° from the polarization plane of the polarizing plate. went. It can be seen from FIG. 3 that the liquid crystal display element 11 of the present example has excellent characteristics in which the reversal phenomenon in which the contrast is reversed in the viewing angle direction and the contrast change in the viewing angle direction are small.

The liquid crystal display element 1 produced in this way
1 can be driven by a driving method such as simple matrix driving or active driving using active elements such as TFT and MIM. In the present invention, the driving method of the liquid crystal display element,
There is no particular limitation.

(Embodiment 2) FIG. 5 is a perspective view for explaining a manufacturing method for manufacturing a liquid crystal display element 11a according to a second embodiment of the present invention, and FIG. 6 is a sectional view for explaining the manufacturing method for this embodiment. It is a figure. The present embodiment is similar to the first embodiment, and corresponding parts are designated by the same reference numerals. In this embodiment,
An ITO film having a thickness of about 100 nm was formed on the two glass substrates 12 and 13 by a vapor deposition method, and a plurality of linear electrodes 14 and 15 were formed by a wet etching method. A polyimide film having a thickness of about 50 nm was applied onto the electrodes 14 and 15 of the glass substrates 12 and 13 by a spin coating method, and baked at 200 ° C. for 1 hour to be cured. Furthermore,
The polyimide film was rubbed in one direction to form alignment films 16 and 17.

The rubbing process is performed on two glass substrates 1
The electrodes 14 and 15 of 2 and 13 are faced to each other,
When the glass substrates 12 and 13 were combined so that 15 was orthogonal to each other, the rubbing directions of the glass substrates 12 and 13 were parallel to each other. For example, SiO beads having a diameter of 1.7 μm are scattered on at least one of the glass substrates 12 and 13, two glass substrates 12 and 13 are bonded together, and a peripheral edge portion is sealed with a sealing material 23 to form a display cell. Configured.

A thermopolymerizable resin similar to that used in Example 1 and 0.75 g of a liquid crystal material ZLI-4237-000 (manufactured by Merck Ltd.) were mixed in the prepared display cell 18a under normal pressure. A liquid crystal cell 19a was constructed by injecting the liquid crystal cell in a state of exhibiting a liquid phase. Then, as shown in FIGS. 5 and 6, a laser beam was applied as a heat beam by point scanning from the end sides of the glass substrates 12 and 13 along the non-picture element portion 22. Specifically, a He-Cd laser is used to first apply a spot to the non-picture element portion 22 at the end of the glass substrates 12 and 13, and then 1 m above the non-picture element portion 22.
Scanning was performed at a speed of m / min.

After the irradiation of the heat beam, the liquid crystal and the polymer undergo phase separation, and the polymer wall 24 is formed at the laser light irradiation portion, while the polymer wall 24 is not formed at the pixel portion. confirmed. Therefore, the liquid crystal display element 11a manufactured in this embodiment can achieve the same effects as those described in the first embodiment. Further, using the liquid crystal display element 11a thus prepared, a shock resistance reliability test including the following pressure test and drop test was conducted. In the pressure test,
When a pressure of 5 kgf / cm ² was applied at a speed of 0.5 mm / min, some disturbance of the alignment was observed in the pressure application part, and in the drop test, the liquid crystal display element 11a was mounted on the floor from a height of 5 cm. I dropped it. As a result, it was confirmed that the alignment disorder in the liquid crystal region 26 was not recognized. From this, it was confirmed that the liquid crystal display element 11b manufactured in this example had a significantly improved impact resistance.

(Embodiment 3) FIG. 7 is a sectional view of a liquid crystal display element 11b manufactured by the manufacturing method of Embodiment 3 of the present invention, and FIG. 8 is a plan view of one glass substrate of the liquid crystal display element 11b. FIG. 9 is a plan view of the other glass substrate of the liquid crystal display element 11b, and FIG. 10 is a cross-sectional view illustrating the manufacturing method of this embodiment. The present embodiment is similar to each of the above-described embodiments, and corresponding parts are designated by the same reference numerals. The liquid crystal display element 11b of this embodiment is manufactured as follows.

Flint glass (manufactured by Nippon Sheet Glass Co., Ltd.,
A plurality of linear electrodes (electrode width 200 μm, electrodes) made of ITO (a mixture of indium oxide and tin oxide, film thickness 50 nm) are formed on a pair of glass substrates 12 and 13 each having a plate thickness of 1.1 mm and 300 mm square. 50 μm and the number of electrodes 1000 × 1000) 14 and 15 are formed. As an example, in a region corresponding to a plurality of electrodes 14 on the glass substrate 12, cobalt nickel is plated to a thickness of 50 μm.
The light-shielding black matrix 29 was formed by forming a linear grid having a width and a matrix substrate. A linear electrode 1 having the same shape as the linear electrode 14 on the glass substrate 12
The counter substrate 5 formed by patterning ITO on the glass substrate 13 and the matrix substrate are combined so that the linear electrodes 14 and 15 are orthogonal to each other, and the cell thickness is made by a spacer having a diameter of 6 μm. Hold
The peripheral portion was sealed with the sealing material 23 to form a display cell.

Next, the aliphatic epoxy resin Denacol EX-314 was added to the prepared display cell as a thermopolymerizable resin.
(Nagase Kasei Co., Ltd.) 0.12 g and curing accelerator Epomic Q-610 (Mitsui Petrochemical Co., Ltd.) 0.006 g
Then, as a liquid crystal material, ZLI-3700-000 (manufactured by Merck & Co.) was added with CN (cholesteric nonanate) 0.3.
A mixture 18b obtained by uniformly mixing with 0.75 g of the mixture added by 0.1% was injected to form a liquid crystal cell 19b.

Next, the coil 30 having the number of turns N is fixed to one side of the liquid crystal cell 19b, and the frequency f = 400 kHz, for example.
A high frequency current of the coil current I was applied at z to perform high frequency induction heating. The principle of high frequency induction heating will be described below.
When a magnetic material or metal is placed in a high frequency magnetic field, heat is generated in an extremely short time due to hysteresis loss and surreal heat due to eddy current. The hysteresis loss and the Joule heat due to the eddy current are expressed by the equations 1 and 2. From such a principle of heat generation, when a high frequency magnetic field is applied to the black mask 29 made of a metal material by using the coil 30,
Hysteresis loss and Joule heat due to eddy current are generated in the black mask 29, the temperature of the black mask 29 is raised, and the portion of the mixture 26 in contact with the black mask 29 is heated, as shown in FIG. Polymer wall 24
Is formed.

In this embodiment, the black mask 29
However, since it is in direct contact with the mixture 26, the heat from the black mask 29 is directly transferred to the mixture 26,
It is possible to perform heating with good heat transfer efficiency. Further, according to such a heat applying method in the present embodiment, in order to form a heat pattern, in addition to the black mask 29 already provided, a new black mask is used to cover the picture elements on the glass substrate. There is no need to attach them so that they do not break.

Therefore, the positional deviation from the picture element that occurs when the new black mask is attached to the glass substrate is eliminated. Further, since the step of attaching the black mask is newly unnecessary, the manufacturing yield is improved and the manufacturing cost is reduced. Also, the heating temperature can be adjusted as appropriate by appropriately adjusting the coil number N, the coil current I, and the frequency f of the coil current. Furthermore, since heating by high frequency induction occurs in a short time, the manufacturing time can be significantly shortened, and the manufacturing efficiency can be improved and the manufacturing cost can be reduced.

In the present embodiment, by selecting these manufacturing methods, the curing point (reaction point) of the polymer material can be appropriately limited, and the mixing of the liquid crystal component into the polymer region, On the contrary, there is an advantage that the mixing of the polymer component into the liquid crystal component can be suppressed.

As the polymerizable resin element composition applied to this embodiment, an acrylic resin, a methacrylic resin, an epoxy resin, a polyimide resin and the like which are polymerized and cured by heat are preferable. On the other hand, with respect to the liquid crystal material used in this example, a liquid crystal excellent in chemical reaction resistance is preferable because it is accompanied by heat and a photopolymerization reaction during processing. Specifically, it is a liquid crystal having a functional group such as a fluorine atom in the compound. More specifically, ZLI-4801-000, ZLI-48
01-001, ZLI-4792 (manufactured by Merck) and the like.

FIG. 11 shows the results of measuring the viewing angle characteristics of the liquid crystal display element 11b produced in this example. In this embodiment, the viewing angle characteristics are measured by tilting the two polarizing plates with respect to the long side of the liquid crystal display element 11b with the polarization axes of the respective polarizing plates at 45 ° in mutually opposite directions. The polarizing plates are attached to the front and back sides of the liquid crystal display element 11b so that the polarization axes thereof are in crossed Nicols, and the normal direction of the liquid crystal display element 11b and the 3 o'clock direction and the 6 o'clock direction inclined by 40 ° from the normal line direction. ,
The light transmittance in the 9 o'clock direction and the 12 o'clock direction was measured by changing the applied voltage. As a result, the display inversion phenomenon and the decrease in contrast due to the increase in transmittance at the time of voltage saturation, which have occurred in the conventional TN type liquid crystal display element, are not observed in any direction, and the viewing angle is reduced. The characteristic is that it becomes extremely wide.

After the measurement of the viewing angle, the glass substrates 12 and 13 of the manufactured liquid crystal display element 11b are separated from each other, and the liquid crystal attached to the surfaces of the glass substrates 12 and 13 is dissolved with acetone. Glass substrate 12, 1 after removal by
The black mask 29 on the surface of No. 3 was observed. It is confirmed that the polymer wall 24 is formed on the black mask 29 between the glass substrates 12 and 13, and the polymer wall 24 is not formed in the region where the black mask 29 is not formed. It was

As described above, in each of the above embodiments, a liquid crystal display device having a liquid crystal region 26 divided by the polymer wall 24, a liquid crystal display device using a ferroelectric liquid crystal, or a light scattering type liquid crystal display device. In the liquid crystal display device, the ratio of the area occupied by the liquid crystal region 26 in the picture element to the polymer wall 24 can be increased. As a result, the contrast at the time of display and the brightness of the display image are improved, and the display quality is improved. Furthermore, the phase separation for forming the liquid crystal region 26 and the region of the polymer wall 24 for each pixel can be performed by irradiation with laser light and high frequency induction heating using the coil 30 and the black mask 29 as described above. The manufacturing process of the liquid crystal display elements 11, 11a and 11b can be remarkably simplified, and the manufacturing time can be remarkably shortened.

In this embodiment, the black mask 2 is used.
9 may be formed of resin mixed with magnetic particles. At this time, the resin may be acrylic resin or polyimide resin.

A modified example of the present invention will be described below.

In the present invention, as a method for applying a heat pattern, it is preferable to utilize laser heat curing by irradiating a laser beam with a coherent light source such as a laser beam. As the type of laser, solid lasers such as dye lasers (BBQ lasers, etc.), He-Cd lasers, YAG lasers, excimer lasers, gas lasers, etc. can be used alone or in combination.

When a coherent light source such as a laser beam is used, it is possible to control the irradiation pattern in the depth direction of the irradiation object by utilizing the interference fringes of the light.
It is even more preferable to use the thermal effect and the optical effect of these laser beams in combination. Besides, a method of irradiating a heat beam through an appropriate pattern having different thermal conductivity is also effective.

Further, regarding a specific method for producing the above liquid crystal display element, as a first method, a heat beam containing these laser beams is made into one straight line by a beam expander, and the polymer is applied from the most end side of the substrate. There is a method of performing a line scan only on the portion to be cured. As a second method, there is a method in which a point scan of only the portion where the polymer is desired to be cured is scanned from the most end side of the substrate with a laser. A third method is to heat a black mask having an arrangement pattern of light-shielding areas corresponding to the arrangement of picture elements by high frequency induction heating, and locally apply heat to the polymer in the portion overlapping with the black mask. The method of hardening is mentioned.

The principle of the high frequency induction heating will be described. When a magnetic material or metal is placed in a high-frequency magnetic field, heat is generated in an extremely short time due to hysteresis loss and Joule heat due to eddy current. The hysteresis loss and the Joule heat due to the eddy current are expressed by the following equation.

[0062]

[Formula 1] Hysteresis loss (W) = n · f · Bm ^1.6 · V n; Hysteresis coefficient f; Frequency (Hz) Bm; Maximum magnetic flux density (wb / m ² ) V; Volume of heated object

[0063]

[Equation 2] Joule heat = K · N ² · I ² · (P · μ · f) ^1/2 K; ratio constant N; coil winding number I; coil current P; specific resistance (μΩ · cm) μ; Effective Permeability Due to such a principle of heat generation, when a high frequency magnetic field is applied to a black mask formed of a material containing at least a magnetic material, hysteresis loss and Joule heat due to eddy current are generated in the magnetic material of the black mask. As a result, the temperature of the black mask is raised, and the portion of the polymer material that is in contact with the black mask is heated.

In a liquid crystal display element in which a black mask is formed on the counter electrode of the liquid crystal display element or on an active matrix element such as a TFT, the black mask is in direct contact with the mixture of the polymerizable resin and the liquid crystal. The heat from the mask is directly transferred to the mixture of the polymerizable resin and the liquid crystal, and heating with good heat transfer efficiency can be performed. Further, according to such a heat application method of the present invention, in order to form a heat pattern, a new black mask is provided in addition to the black mask already provided so as not to cover the pixel region from the glass substrate. There is no need to attach it to.

Therefore, the positional deviation from the picture element region which occurs when the new black mask is attached to the glass substrate is eliminated. Further, since the step of attaching the black mask is newly unnecessary, the manufacturing yield is improved and the manufacturing cost is reduced. Conventionally, it has been necessary to remove a black mask for forming a heat pattern from a glass substrate after forming a polymer matrix by thermosetting.

Further, the heating temperature can be set to a desired temperature by appropriately adjusting the number of coils N, the coil current I, and the frequency f.

Further, since the heating by the high frequency induction occurs in a short time, the manufacturing time can be greatly shortened, the manufacturing efficiency can be improved and the manufacturing cost can be reduced.

By selecting these methods, the curing point (reaction point) of the polymer material can be appropriately limited, and the liquid crystal component is mixed into the polymer region, or conversely, the liquid crystal component is mixed. There is an advantage that the mixing of the polymer component can be suppressed.

When the method of the present invention is applied to a polymerizable resin element composition used as a prepolymer (monomer or oligomer), an acrylic resin, a methacrylic resin, an epoxy resin, a polyimide which is polymerized and cured by heat is used. Resins and the like are preferable. These polymers are substances that finally form a polymer matrix that supports liquid crystal droplets, and the selection thereof is important. Especially when performing TFT drive,
The liquid crystal and polymer in the liquid crystal display element are required to have electrical insulation, and the specific resistance of the monomer is 1 × 10 ¹² Ω ・ in the uncured state.
cm or more is required.

On the other hand, the liquid crystal material is an organic mixture showing a liquid crystal state at around room temperature, which includes nematic liquid crystal (including dual-frequency driving liquid crystal and liquid crystal with dielectric anisotropy Δε <0) and cholesteric liquid crystal. (In particular, a liquid crystal having a selective reflection property for visible light), or a smectic liquid crystal, a ferroelectric liquid crystal, a discotic liquid crystal and the like are included. These liquid crystals may be mixed, and in particular, nematic liquid crystals, nematic liquid crystals to which cholesteric liquid crystals are added, and ferroelectric liquid crystals are preferable in terms of characteristics. More preferably,
A liquid crystal excellent in chemical reaction resistance is preferable because it is accompanied by heat and photopolymerization during processing. Further, the FLC type liquid crystal or ST
When the influence of the initial alignment regulating force of the liquid crystal material such as N-type liquid crystal is important, a liquid crystal display element having a configuration in which conventionally used mode liquid crystal is divided by a polymer matrix may be used. Specifically, it is a liquid crystal having a functional group such as a fluorine atom in the compound. More specifically, ZL
I-4801-000, ZLI-4801-001, Z
LI-4792 (manufactured by Merck) and the like.

By sandwiching the element produced by the present invention between two polarizing plates, a display element (TN, STN, etc.) which has been used conventionally and which has a high contrast and has a sharp change in the amount of transmitted light when a driving voltage is applied. It is possible to form a liquid crystal element in which a liquid crystal material is surrounded by a polymer material and a liquid crystal layer is pseudo-solidified by locally forming an ECB, a ferroelectric liquid crystal element, or the like) in a polymer.

The liquid crystal display device produced by the method of the present invention has a structure in which liquid crystal domains are radially or randomly aligned in the liquid crystal region. As a result, when the drive voltage is applied, the rising directions of the liquid crystal molecules are oriented in almost all directions, so that the viewing angle characteristics are improved. That is, when a voltage is applied, the interaction between the liquid crystal molecules and the polymer wall made of a polymer material causes the liquid crystal molecules to tilt toward each polymer wall. The state is almost the same at any viewing angle, and the viewing angle characteristics of the liquid crystal display device are improved.

By this method, specifically, a liquid crystal display device having a structure in which liquid crystal domains in a liquid crystal region are oriented radially or randomly can be prepared. In this way, the liquid crystal display device produced is composed of simple matrix drive, TFT,
MIM (metal-insulator-metal structure switching element)
It is driven by a driving method such as active driving using an active element such as. However, in the present invention, the method of driving the liquid crystal display element is not particularly limited.

[0074]

According to the manufacturing method of the present invention, the phase separation method of liquid crystal and polymer material, which has not been achieved in the conventional liquid crystal display device, can be performed by a simple method without using a photomask, and the liquid crystal And the polymer can be separated from each other without being taken in each other, and a large-screen display element having a liquid crystal region partitioned by the polymer material can be manufactured. Therefore, the display quality of the manufactured liquid crystal display device can be improved, and the manufacturing process is remarkably simplified and shortened.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating a manufacturing method according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating the manufacturing method of the present embodiment.

FIG. 3 is a cross-sectional view showing a halftone state of a liquid crystal display element manufactured according to this example.

FIG. 4 is a diagram showing viewing angle characteristics of the liquid crystal display element of Example 1.

FIG. 5 is a perspective view illustrating a manufacturing method according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a second embodiment.

FIG. 7 is a cross-sectional view of a liquid crystal display element manufactured in Example 3 of the present invention.

FIG. 8 is a plan view of one substrate of the liquid crystal display element of the present embodiment.

9 is a plan view of the other substrate of Example 3. FIG.

FIG. 10 is a diagram showing the principle of the manufacturing method according to the third embodiment.

FIG. 11 is a diagram showing the transmittance characteristics of the liquid crystal display element created in Example 3;

FIG. 12 is a cross-sectional view showing a halftone state of a conventional TN type liquid crystal display element.

[Explanation of symbols]

 11, 11a, 11b Liquid crystal display device 12, 13 Glass substrate 14, 15 Electrode 18 Mixture 20 Laser light 24 Polymer wall 29 Black mask 26 Liquid crystal region 27 Liquid crystal molecule 30 Heating coil 31 Magnetic field line

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Wataru Horie 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka

Claims (8)

[Claims] 1. An injection step of injecting a mixture of a liquid crystal material, a polymerizable resin composition and a polymerization initiator between a pair of substrates, at least one of which is transparent, and a pattern of locally strong and weak patterns in the mixture. And a heating step of applying heat and light in combination, wherein the polymerizable resin composition in the mixture is polymerized by the applying step to thereby separate the liquid crystal material and the polymerizable resin composition. A method for manufacturing a liquid crystal display element, which comprises phase-separating liquid crystal regions separated by a polymer material. 2. The application of the heat is performed by heat of a heat beam or a heat effect of a coherent light beam, and progresses the polymerization of the polymerizable resin composition and the phase separation in the mixture. 1. The method for manufacturing the liquid crystal display element according to 1. 3. The method for manufacturing a liquid crystal display device according to claim 1, wherein the application of heat is performed by linearly irradiating heat by a heat beam or a coherent light beam. 4. The method for manufacturing a liquid crystal display element according to claim 1, wherein the application of heat is performed by irradiating a heat beam or a coherent light beam in a dot-sequential manner. 5. The heat applied to the pair of substrates in which at least one of the substrates is provided with a black mask made of a light-shielding material uses heat generated by high-frequency induction heating of the black mask. Item 2. A method for manufacturing a liquid crystal display element according to item 1. 6. The method according to claim 5, wherein the black mask is made of a magnetic material such as cobalt nickel. 7. The method for manufacturing a liquid crystal display element according to claim 5, wherein the black mask is made of a resin mixed with magnetic particles. 8. The method for manufacturing a liquid crystal display element according to claim 7, wherein the resin is an acrylic resin or a polyimide resin.