JPH08152609A - Liquid crystal display element and its production - Google Patents

Abstract

PURPOSE: To provide a liquid crystal display element which prevents a cell thickness from being changed by external force, facilitates driving control and is exceedingly improved in visual angle characteristics. CONSTITUTION: Plural transparent electrodes 14 corresponding to plural picture elements 21 set in a matrix form are formed on a substrate 12 and an oriented film 15 is formed to coat this substrate 12. Plural transparent electrodes 16 constituting plural picture elements 21 facing the transparent electrodes 12 on the substrate 1 are formed on another substrate 13 and an oriented film 17 is formed to cover the substrate 13. High-polymer walls 18 which are wall structural bodies forming liquid crystal regions 19 are formed in the plural regions corresponding to the respective picture elements 21 between the respective substrates 12 and 13. These high-polymer walls 18 have unit walls partially or wholly enclosing liquid crystals by each of the respective picture elements 21. Polarizing plates 24, 25 are respectively arranged on the outer sides of the respective substrates 12, 13.

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 (hereinafter referred to as a .pi. Cell) which has liquid crystal molecules each of which is at least partially surrounded by a polymer wall and which has a bend orientation.

The liquid crystal display device of the present invention has the following characteristics.

By having a polymer wall surrounding a liquid crystal region, which is a region for each picture element of a liquid crystal layer sandwiched between a pair of substrates,
It is possible to prevent variation in the distance between the substrates when an external force is applied, and it is possible to prevent the display unevenness of the liquid crystal display element based on the variation in the distance. Thus, by using a transparent position detection film that can be arranged on the surface of the liquid crystal display element and a pen-shaped input means that presses a desired portion of the position detection film, instead of manual key input using a keyboard. It can be used as a liquid crystal display device capable of pen input operation.

Since the alignment direction of the liquid crystal molecules in the liquid crystal region is in a self-compensating alignment state as described later, the viewing angle characteristic is improved. Furthermore, since the bend orientation is achieved, the response speed is fast.

The device does not require a voltage application for obtaining an initial orientation for a normal π cell, and a driving method usually used for a liquid crystal display device can be used.

From the above characteristics, the device of the present invention is suitable for a portable display device that requires pen input, a display device that can be seen by a plurality of people, a high-definition large-screen device, and the like. Further, it can be used in the field where the current liquid crystal element is used. For example, flat-panel display devices such as personal computers, liquid crystal televisions, portable displays (including film substrates),
It can be used for glasses-type displays.

[0007]

[Prior art]

(Related to π cell) Prior art, for example, JP-A-61-11
In the structure of the π cell 1 disclosed in Japanese Patent No. 6329, as shown in FIG. 14A, a liquid crystal layer 4 is sandwiched between a pair of glass substrates 2 and 3, and the liquid crystal molecules 5 of the liquid crystal layer 4 are Spray orientation is carried out when no voltage is applied, and this state is a thermally stable state. When a voltage is applied to the π cell 1 by using a power source 6 under a certain condition, the liquid crystal molecules 5 are first shown in FIG.
As shown in (2), the bend alignment state is established. Since this alignment state has a reverse pretilt angle and a high pretilt angle, the liquid crystal molecules 5 are easily driven by an external voltage, the response speed is fast, and the drive voltage is low. Further, the bend alignment is a so-called “self-compensation” in which the liquid crystal molecules 5 mutually compensate in the π cell 1 because the liquid crystal molecules 5 are arranged symmetrically with respect to the center plane between the liquid crystal cell substrates 2 and 3. The cell has a viewing angle characteristic that is bilaterally symmetric with respect to the direction in which the observer views the π cell 1. Furthermore, Japanese Patent Laid-Open No. 1-20942
No. 4, JP-A-2-306217, a uniaxial optical compensator made of a uniaxially stretched polymer material is added to a liquid crystal cell having a liquid crystal layer sandwiched between a pair of transparent substrates. If the effective retardation d · Δn of the liquid crystal cell and the retardation Δn · d of the uniaxial optical compensator are approximately the same in the direction perpendicular to the major axis of the liquid crystal molecules, the viewing angle It is disclosed that the characteristics are omnidirectional.

However, the liquid crystal cell has a structure in which the liquid crystal material and the spacers are only partially mixed between the substrates, and a transparent position detecting film is arranged on the surface of the liquid crystal cell. When a pen input operation is performed using a pen-shaped input unit that presses a desired portion, the cell thickness changes due to an external force such as a pen input, which causes display quality deterioration such as display unevenness. Furthermore, the orientation state (bend state) of the π cell is not thermally stable, and when the voltage applied to the π cell is turned off, it slowly changes and returns to the thermally stable spray orientation state. Therefore, when using this π cell, an electric field is required to maintain the bend alignment state, resulting in high power consumption,
Further, there is a problem that the driving method becomes complicated.

As a π cell which does not require initial alignment by a voltage for bringing liquid crystal molecules into a bend alignment state, a high tilt substrate which can realize a high pretilt angle of liquid crystal molecules by oblique vapor deposition of CeO ₂ is used. A liquid crystal display device in which bend alignment is performed by using a liquid crystal cell which is not parallel to and parallel to each other is reported in Proceedings of the Spring Meeting of the Japan Society of Applied Physics 1p-R-8, p122 (1980). However, with the vapor deposition technology used in this report, it is difficult to uniformly and reproducibly form a vapor deposition film on a large-sized substrate, and a technology for mass-producing large-scale, high-display-quality liquid crystal display devices with high productivity. Is not suitable for.

(Liquid crystal cell having polymer wall) As a liquid crystal cell having polymer walls for connecting the respective substrates, which does not require a polarizing plate and does not require alignment treatment, birefringence of liquid crystal A technique for electrically controlling the transparent or cloudy state by utilizing the rate has been proposed. This technology basically matches the ordinary refractive index of the liquid crystal molecules with the refractive index of the support medium, displays a transparent state when a liquid crystal is aligned by applying a voltage, and displays a liquid crystal molecule when no voltage is applied. The light scattering state, that is, the white turbid state, due to the disordered orientation is displayed.

As a proposed conventional technique, a liquid crystal and a photocurable resin or a thermosetting resin are mixed and injected into a substrate as disclosed in Japanese Patent Publication No. 61-502128, and then the resin is cured. Accordingly, a method of forming a polymer wall by depositing liquid crystals between the substrates and forming liquid crystal droplets in the resin is disclosed.

As a method for improving the viewing angle characteristics of a liquid crystal cell using a polarizing plate for non-scattering type display, Japanese Patent Laid-Open No. 2724/1993 has been proposed.
Japanese Patent Publication No. 2 discloses a method for producing a composite material of a liquid crystal and a polymer material by phase separation in which the liquid crystal and the polymer resin are separated from a mixture of the liquid crystal and the photocurable resin. According to this method, the orientation state of the liquid crystal domains becomes random due to the produced polymer, and the rising directions of the liquid crystal molecules in the individual liquid crystal domains differ when a voltage is applied. Therefore, the apparent refractive indices of the liquid crystal cell when viewed from each direction are equal to each other. For this reason, the viewing angle characteristics in the halftone state are improved.
Recently, the inventors of the present application have filed a Japanese Patent Application No. 4-286487 as a liquid crystal element having a significantly improved viewing angle characteristic as described below. In this liquid crystal element, when the photopolymerization of irradiating the mixed material of the liquid crystal and the photocurable resin with light is controlled by using a photomask or the like, the irradiation state of the light is controlled so that the liquid crystal domain is completely covered within the pixel region. The liquid crystal molecules in the liquid crystal domain behave as if the umbrella were opening and closing by controlling the voltage by applying or blocking a voltage to the liquid crystal molecules in a directional alignment state (radial alignment). The characteristics are remarkably improved.

Further, the inventors of the present invention have proposed a method of effectively utilizing the alignment regulating force for liquid crystal molecules on the substrate surface and producing a liquid crystal display element in the polymer wall using the alignment regulating force on the substrate surface. , Japanese Patent Application No. 5-30996. These inventions relate to TN, STN, ECB, and FLC mode liquid crystal elements.

(Alignment-stabilized cell with cross-linked polymer) S
Using a cell in which the substrate is oriented for TN or TN mode,
By injecting a mixture of a liquid crystal material and a small amount of a photocurable resin into a cell and then irradiating with ultraviolet rays, a liquid crystal display element having a stable alignment state can be produced.
No. 0801 and Japanese Patent Laid-Open No. 6-160814.

(Control of Liquid Crystal Alignment by Voltage and Magnetic Field) As a method of controlling the alignment of the liquid crystal in the liquid crystal cell, the mixture of the liquid crystal and the photocurable resin is irradiated with ultraviolet rays while applying a minute voltage to the liquid crystal. Japan Display 92 S18 is a method to improve the hysteresis characteristics of the liquid crystal cell display by giving a small pretilt angle to the liquid crystal molecules inside the droplets.
-4, p699.

[0016]

In the conventional π-cell liquid crystal display element, the cell thickness changes due to an external force, and display unevenness locally occurs due to pen input or the like.

Further, in the conventional π-cell liquid crystal element, the bend orientation cannot be stably and easily obtained.

The present invention has been made in order to solve the above problems, and its purpose is to prevent the cell thickness from being changed by an external force, improve the display quality, and stabilize the bend alignment of liquid crystal molecules. The liquid crystal display device has a significantly improved viewing angle characteristic because it can be easily and easily controlled, and the alignment direction of the liquid crystal molecules in the liquid crystal region is in a self-compensating alignment state. And a method for manufacturing a liquid crystal display device capable of manufacturing a large-sized, high-display-quality liquid crystal display device with high production efficiency.

[0019]

In order to solve the above-mentioned problems, the inventors of the present invention have defined that the inside of a liquid crystal display element is partitioned by a polymer wall in order to provide a cell with a supporting force against an external force. It has been found that the above problems can be solved by inventing a liquid crystal display element having twisted molecules and fixing the bend orientation of the liquid crystal molecules at the time of cell production.

The present invention will be described in more detail below.

The liquid crystal display device of the present invention comprises a pair of electrode substrates in which a plurality of picture elements are arranged in a matrix, electrodes are formed on the respective surfaces, and at least one surface is subjected to a rubbing treatment, and the pair of electrode substrates. And a wall structure having a shape in which a unit wall structure is repeated for each picture element, and at least partially surrounded by the wall structure, and for each picture element between the pair of electrode boards. In the liquid crystal layer including the formed liquid crystal small region, the liquid crystal molecules of the liquid crystal small region included in the liquid crystal layer are oriented in a plane symmetry with respect to the center plane between the electrode substrates, and are bend-aligned. The liquid crystal layer is provided, and thereby the above object can be achieved.

In the present invention, the pair of electrode substrates may be in close contact with the wall structure.

In the present invention, a polymer liquid crystal material may be included in the material forming the wall structure.

In the present invention, a pair of polarizing plates whose polarization axes are orthogonal to each other are arranged on each surface of the pair of electrode substrates, and one polarizing plate of the pair of polarizing plates has the polarizing axis. In some cases, the angle may be set to about 45 ° from the rubbing direction of the electrode substrate.

In the present invention, the liquid crystal molecule has a principal axis in a direction orthogonal to the long axis direction and is equal to the product d · Δn of the layer thickness d of the liquid crystal layer and the effective refractive index anisotropy Δn. In some cases, either a uniaxial optical compensating plate or a biaxial optical compensating plate having substantially the same retardation value is installed between the liquid crystal layer and either one of the polarizing plates.

In the present invention, the material of at least one of the pair of electrode substrates may be a polymer material that transmits visible light at at least part of the wavelength.

In the present invention, the refractive indices n _o (ordinary ray refractive index) and n _e (extraordinary ray refractive index) of the liquid crystal material constituting the liquid crystal layer, and the refraction of the polymer material forming the wall structure Rate n
relationship with _p is, | sometimes defined to be a ≦ 0.1 | ((n _e or n _o) -n _p).

In the method for producing a liquid crystal display element of the present invention, at least one of a liquid crystal material, a mixture of a liquid crystal compound having a polymerizable functional group in the molecule, a polymerizable compound and a photopolymerization initiator is transparent. A liquid crystal cell containing the pair of electrode substrates and the mixture while applying at least one of an electric field and a magnetic field after injection between the pair of electrode substrates having at least one surface subjected to rubbing treatment. A pair of electrode substrates is irradiated with light having a regular spatial intensity in the irradiation intensity corresponding to a plurality of picture elements set in a matrix, and the liquid crystal and the polymer material are phase-separated by a photopolymerization reaction, A polymer wall having a shape in which a unit wall structure is repeated for each picture element, at least a part of which is surrounded by a liquid crystal material in the polymer wall;
The liquid crystal molecules in the small liquid crystal region included in the liquid crystal layer are formed so as to be substantially plane-symmetrical with respect to the center plane between the electrode substrates and bend-aligned, thereby achieving the above object. can do.

In the present invention, a photomask may be used as a method for making regular light intensity.

In the present invention, the mixture in the liquid crystal cell including the pair of electrode substrates and the mixture has a regular spatial intensity in irradiation intensity at a temperature equal to or higher than the homogenizing temperature of the liquid crystal material. In some cases, light is used for photopolymerization, and then the material is gradually cooled while applying at least one of an electric field and a magnetic field.

In the liquid crystal display device of the present invention, a liquid crystal layer and a polymer layer are sandwiched between a pair of electrode substrates, and the liquid crystal molecules of the liquid crystal layer are bend-aligned with the center plane between the electrode substrates being substantially plane symmetry. A liquid crystal display device, wherein the liquid crystal layer and the polymer layer are phase-separated from a mixed liquid of at least 0.1 to 5% by weight of a polymer cross-linked product and a liquid crystal material. Can be achieved.

In the present invention, a liquid crystal compound having a polymerizable functional group may be contained in the molecule in the crosslinked polymer.

In the present invention, a pair of polarizing plates whose polarization axes are orthogonal to each other are provided above and below a cell in which a liquid crystal layer and a polymer wall surrounding the liquid crystal layer are sandwiched between the pair of electrode substrates. In some cases, the polarization axis of is set at about 45 ° from the rubbing direction of the alignment film on the electrode substrate.

In the present invention, a uniaxial optical compensator or a biaxial optical compensator is provided on either side of the liquid crystal layer so that the major axis of the liquid crystal molecules of the liquid crystal layer and the principal axis of the optical compensator are orthogonal to each other. There is a case where at least one sheet is installed between the sheet and the polarizing plate.

In the method for manufacturing a liquid crystal display element of the present invention, a liquid crystal layer and a polymer layer are sandwiched between a pair of electrode substrates, and liquid crystal molecules of the liquid crystal layer make the center plane between the electrode substrates substantially plane-symmetric. A method of manufacturing a liquid crystal display device having bend alignment, comprising:
Between 1 to 5% by weight of a mixture of a polymerizable compound containing at least a liquid crystalline compound having a polymerizable functional group in the molecule in a crosslinked polymer and a liquid crystal material, at least one of which is transparent between the electrode substrates. After the injection, the bend alignment of the liquid crystal molecules is stabilized while applying at least one of an electric field and a magnetic field, and light or heat energy is added to the mixture so that the energy intensity corresponds to the picture element, and the liquid crystal layer. And a polymer layer are phase-separated, whereby the above object is achieved.

[0036]

According to the present invention, the phase separation between the liquid crystal and the polymer material (polymerization of the monomer) is performed in the voltage application state, that is, in the π cell orientation state, so that the initial phase required in the conventional π cell is obtained. It is not necessary to apply a voltage for orientation, and orientation can be performed in a stable state. Further, since the polymer wall is formed in the liquid crystal display element, it is possible to prevent the display characteristics from changing when the pen is input.

Further, in the present invention, a liquid crystal phase and a polymer phase (polymer) are prepared from a mixed liquid of at least 0.1 to 5% by weight of a crosslinked polymer and a liquid crystal material in a voltage applied state (π cell orientation state). Since the film) is phase-separated, the voltage application for the initial alignment, which was necessary in the conventional π-cell, is unnecessary, the liquid crystal molecules are in bend alignment in a stable state, and the cell drive voltage and contrast etc. The display characteristics of are good. If the amount of the photopolymerizable resin exceeds 5% by weight, a large number of polymer walls are formed in the pixel region, the driving voltage of the cell is significantly increased, and the scattering phenomenon due to the difference in the refractive index between the liquid crystal and the polymer occurs. It becomes noticeable and reduces the contrast. On the other hand, if the addition amount of the photocurable resin is less than 0.1%, the liquid crystal layer aligned along the alignment regulating force of the polymer on the substrate decreases, and the practicality is lost.

Further, when a uniaxial optical compensating plate or a biaxial optical compensating plate is used as in the present invention, wide viewing angle characteristics are obtained.

[0039]

EXAMPLES Examples of the present invention will be described in more detail below.

(Liquid Crystal Cell Structure) The liquid crystal cell 11 of the present invention
As shown in FIG. 1, at least one includes a pair of substrates 12 and 13 that transmits visible light at some wavelengths. A plurality of transparent electrodes 14 corresponding to the plurality of picture elements 21 set in a matrix on the substrates 12 and 13 are formed on the substrate 12, and the alignment film 15 is formed to cover the substrate 12. A plurality of transparent electrodes 16 constituting the plurality of picture elements 21 are formed on the other substrate 13 so as to face the transparent electrodes 12 on the substrate 12, and an alignment film 17 is formed to cover the substrate 13. It A rubbing process, which will be described later, is performed on these alignment films 15 and 17. A polymer wall 18, which is a wall structure that forms a liquid crystal region 19, is formed in a plurality of regions corresponding to the picture elements 21 between the substrates 12 and 13. The polymer wall 18 has a unit wall that partially or entirely surrounds the liquid crystal for each picture element 21. Polarizing plates 24 and 25 are arranged on the outer sides of the substrates 12 and 13, respectively.

The liquid crystal cell 11 of this embodiment is composed of the picture elements 2
Each one has a microcell structure in which a liquid crystal region 19 substantially surrounded by a polymer wall 18 is bend-aligned between the substrates 12 and 13 having the transparent electrodes 14 and 16. As for the polymer wall 18 of the present invention, as described in Japanese Patent Application Laid-Open No. 4-323616, a polymer wall is prepared on one substrate in advance and then the other substrate is made to face each other. Different from polymer wall by the method of injecting a liquid crystal material between the substrates, which is made into cells with a structure fixed by a sealing material,
It is characterized in that the upper and lower substrates 12 and 13 and the polymer wall 18 are closely adhered or adhered to each other. Upper and lower substrates 12, 13
Since the liquid crystal cell 11 of the present invention has the polymer wall 18 adhered to it, the fluctuation of the cell thickness due to an external force can be further suppressed, and a pen-shaped liquid crystal cell can be formed by using a transparent film for position input on the conventional liquid crystal cell. It is possible to prevent the color change of the liquid crystal cell, which is observed when the pen input is performed using the input means. Furthermore, impact resistance when the liquid crystal cell 11 is dropped is significantly improved.

Further, when a large-screen liquid crystal display device is erected upright, in a liquid crystal cell having a structure in which a liquid crystal layer is injected between substrates, the cell thickness at the lower portion becomes thick due to the weight of the liquid crystal material, and the upper and lower portions of the liquid crystal cell are There was display unevenness in the direction. In the present invention, in the liquid crystal cell 11 having the polymer wall 18 in which the substrates 12 and 13 are adhered to each other, the cell thickness variation is extremely small. Further, when a polymer liquid crystal material having the same effect as the alignment influence force on the liquid crystal molecules on the substrates 12 and 13 is fixed in the polymer wall 18, the alignment regulating force is applied to the substrates 12 and 13 from the substrate surface. Since it affects both the horizontal direction and the vertical direction from the vertical surface 23 of the polymer wall 18 to the substrates 12 and 13, the alignment state of the bend alignment of liquid crystal molecules having a high tilt angle and poor stability is extremely high. Stabilizes to.

Further, since the majority of the polymer wall 18 is intentionally produced outside the picture element, the polymer material existing in the picture element is higher than that when the polymer wall 18 is prepared at an arbitrary position. Thus, it is possible to prevent a decrease in contrast due to black display under the crossed Nicols. Further, a polymer thin film may be formed at the interface where the liquid crystal region 19 and the substrates 12 and 13 are in contact with each other, but in this case as well, the alignment regulating force on the substrates 12 and 13 may be formed. Is transmitted to the liquid crystal molecule 20 through the polymer, the liquid crystal molecule 2
A uniform orientation of 0 is obtained. Further, since the polymer wall 18 and the polymer thin film wrap the liquid crystal region 19 three-dimensionally, the liquid crystal cell 11 of the present invention is further improved in strength against an external force when the pen is input. .

(Manufacturing Method) In the method of manufacturing the liquid crystal display device of the present invention, when manufacturing the liquid crystal cell 11 shown in FIG. 1, the alignment regulating force (the reverse pretilt angle is applied to the liquid crystal molecules to the liquid crystal molecules of the substrates 12 and 13 is set. And the polymer wall 18 is formed substantially outside the picture element 21. To this end, the present invention is to inject a mixture of a liquid crystal material and a photocurable resin (including a liquid crystal curable resin and a photopolymerization initiator) between the alignment-treated substrates 12 and 13, and then
This is a manufacturing method in which at least one of an electric field and a magnetic field is applied to the liquid crystal cell 11, and ultraviolet rays are partially irradiated so that the ultraviolet rays do not substantially irradiate the pixel 21 portion.

In the manufacturing method of the present invention, the polymer material is polymerized and formed in the region irradiated with ultraviolet rays, and the liquid crystal material is extruded into the region not irradiated with ultraviolet rays. A liquid crystal region 19 is formed in the non-irradiation region. In order to utilize the alignment regulating force of the substrates 12 and 13, by using a photocurable resin material having liquid crystallinity in a part or all of the photocurable resin, the liquid crystallinity of the liquid crystal-photocurable resin mixture is impaired. Photopolymerization can be carried out without. At this time, in the phase separation process between the liquid crystal and the polymer material, at least one of an electric field and a magnetic field is applied from the outside, so that the liquid crystal region 19 that has been phase-separated is separated from the substrate 12.
The liquid crystal molecules 20 in the liquid crystal region 19 grow in the bend alignment due to the alignment regulating force of 13 and the effect of the external field.

Finally, since the liquid crystal molecules 20 in the liquid crystal region 19 are in the bend alignment state and the surrounding polymer material is cured, the polymer films attached on the substrates 12 and 13 are changed to liquid crystal molecules. It becomes an alignment film that gives a high pretilt angle to 20, and the alignment state of the liquid crystal is stabilized.

Further, in the manufacturing method of the present invention, the mixture is injected into a cell having a structure in which the pair of substrates 12 and 13 are fixed by a sealing material at a temperature equal to or higher than the homogenizing temperature of the mixture, and the UV irradiation intensity is intentionally increased. The regular strength and weakness is attached to and the photopolymerization is caused regularly. Furthermore, in order to impart liquid crystal properties to the mixture, by gradually lowering the cell temperature to a nematic or smectic phase and further causing photopolymerization,
A uniform alignment state of the liquid crystal molecules 20 over the front surfaces of the substrates 12 and 13 can be obtained. At this time, as the liquid crystal used is a smectic phase liquid crystal having higher crystallinity, the photocurable resin that has entered the liquid crystal can be excluded to the outside of the liquid crystal, so that a polymer material is formed in the pixel 21. As a result, it is possible to prevent a decrease in contrast, and it is possible to realize the liquid crystal display cell 11 having a more preferable display quality.

(How to give unevenness of illuminance of irradiated ultraviolet rays) In the present invention, how to give an ultraviolet (hereinafter, UV) illuminance distribution is important. Is preferably attached. The position of the photomask may be inside or outside of the cell, and it is sufficient as long as UV light can be regularly formed. Moving the photomask away from the cell blurs the optical image on the mixture due to the image on the mask, reducing the effect of the invention. Therefore, the photomask is preferably provided as close to the liquid crystal-photocurable resin mixture as possible. That is, when a substantial photomask for cutting off ultraviolet light is present in the cell, the photomask comes into contact with the mixture of the liquid crystal and the photocurable material, which is particularly preferable. As a specific example, when the liquid crystal cell of the present invention is applied to a reflective liquid crystal display element, a method of leaving a reflection function only in a portion corresponding to a picture element of a reflection plate and making a portion other than each picture element a transmissive region, Alternatively, a method is preferable in which a film that transmits visible light and blocks ultraviolet light is regularly formed on one substrate in a region other than the ultraviolet irradiation region in units of 21 pixels. This method can be specifically realized by using a color filter in the cell, an organic polymer film, or the like.

It is desirable that the UV light source be as parallel rays as possible in terms of the accuracy of the optical image on the mixture. When the parallelism of the actinic light is impaired, ultraviolet light enters the non-irradiated area and the polymer material is hardened in the area of the picture element 21, so that the contrast is lowered as described above.

According to the results of examination by the present inventors, when the uneven illuminance imparting means is used, the size of the uneven illuminance, that is, the size of the weak illuminance region is 30% or less of the size of the picture element 21.
The generated liquid crystal droplet is also 3 times the size of the pixel 21.
The size becomes 0% or less, the number of interfaces between the liquid crystal and the polymer increases in the pixel 21, and the contrast is greatly reduced due to light scattering by the interfaces. A non-uniform illuminance imparting means having a weak illuminance region larger than the size of the picture element 21 in which the interface between the liquid crystal and the polymer is extremely small in the picture element 21 is preferable, and only the portion other than the picture element 21 is irradiated with UV light. A photomask or the like is preferable.

Further, the shape of the weak illuminance region of UV light may be any shape as long as it covers 30% or more of the picture element 21 and locally reduces the UV intensity. Squares, trapezoids, rectangles, hexagons, rhombuses, letters, figures delimited by curves and straight lines, and
It is an aggregate of these small figures. A photomask or the like in which the portion of the pixel 21 is a weak illuminance region is preferable because it reduces the scattered light intensity in the pixel 21 and improves the display contrast of the liquid crystal display element. Further, in carrying out the present invention, one or more kinds of these figures may be selected and used. Preferably, in order to improve the uniformity of the liquid crystal droplets, it is preferable to limit the shapes to one kind as much as possible.

The feature of the present invention resides in that the liquid crystal regions 19 are regularly arranged in the horizontal direction, that is, in alignment with the picture elements 21, and the arrangement state of the weak illuminance region for that is important. The arrangement of the weak illuminance area is preferably in accordance with the pitch of the picture element 21, and it is preferable to arrange one weak illuminance area in one picture element 21.

On the other hand, the weak illuminance area may be arranged over several picture elements 21, and the weak illuminance area may be arranged for each column of the matrix-shaped picture elements 21 as a whole, or for each set of several picture elements as a whole. A weak illuminance area may be arranged in the area. Further, the weak illuminance regions do not need to be independent of each other and may be connected to each other at the end portion, as long as the region that most effectively cuts UV light has the above shape and arrangement. Good. Further, when the picture element 21 is large, the polymer wall 18 may be intentionally formed in the picture element 21. In this case, although the contrast is reduced, the supporting force for the external pressure is improved.

(Method of Applying Electric Field or Magnetic Field) Irradiating the mixture of the liquid crystal and the photocurable resin with ultraviolet rays while applying at least one of the electric field and the magnetic field forms the bend alignment state used in the present invention. Is important to let. By applying an external field, the liquid crystal layer that has been spray-aligned becomes a bend alignment state. In order to fix this state, the ultraviolet curable resin is cured by ultraviolet rays. The applied electric field and magnetic field strength differ depending on the cell thickness, the anisotropy of the dielectric constant of the liquid crystal material, the elastic constant, etc., and are not particularly limited in the present invention, but may be at least the strength at which the bend alignment becomes more stable than the spray alignment. .

Furthermore, the voltage may be a voltage immediately before a high voltage is applied to change from the bent orientation to the spray orientation.

(Roughness of display) Due to the difference in refractive index at the interface between the polymer material and the liquid crystal material, in the conventional polymer dispersion type liquid crystal display element, the scattering phenomenon occurs at the interface. The same scattering phenomenon occurred in a liquid crystal element having a large liquid crystal region 19 and surrounded by a polymer wall of a non-scattering type liquid crystal display element for reading the alignment state of liquid crystal molecules by a polarizing plate. This scattering phenomenon causes the display to be rough and deteriorates the display quality. However, in the present invention, even in the polymer material, the liquid crystal material and the liquid crystal photopolymerization material have an almost similar alignment state before and after the curing of the photocurable resin, and the liquid crystal material and the liquid crystal photopolymerization material have almost the same refractive index. Therefore, the roughness on the display is significantly reduced. Furthermore, since the amount of the photopolymerizable resin added to the liquid crystal material is small, that is, the proportion of the polymer present in the liquid crystal is small, the above scattering phenomenon is reduced.

(Liquid-Crystalline Polymerizable Material) In the method for producing a liquid crystal display device of the present invention, a pair of substrates 12 each containing a polymerizable compound are prepared from a uniform mixture of a liquid crystal material and a polymerizable compound containing a polymerizable compound having liquid crystallinity. 13 is a method in which the liquid crystal and the polymer material are phase-separated by curing while being aligned in the liquid crystal state. A structure in which a liquid crystal compound is fixed on the polymer wall 18 can be produced. As a result, the liquid crystal molecules 20 receive an alignment regulating force not only from the surfaces of the substrates 12 and 13 but also from the vertical surface 23 of the polymer wall 18 shown in FIG. It is also possible to ensure the uniformity of orientation near the polymer wall 18. On the other hand, in the conventional method in which a wall is formed on the surface of one substrate and then the other substrate is fixed, the alignment is disturbed in the vicinity of the polymer wall, and display uniformity cannot be maintained.
The present invention solves this problem and achieves display uniformity.

In order to stabilize the bend alignment of the present invention, it is preferable that the mixture of the liquid crystal and the photocurable resin is irradiated with ultraviolet rays in the liquid crystal state and in the voltage applied state. Thereby, the effect of the present invention can be expected. Therefore, it is preferable to use a liquid crystalline polymer material having a functional group likely to exhibit liquid crystallinity in the photocurable resin.

The compound having a liquid crystalline functional group in the molecule used in the present invention is a compound represented by the following (Chemical formula 1) or (Chemical formula 2).

[0060]

## STR1 ## AB-LC ₁

[0061]

Embedded image A-B-LC ₂ -BA A in the above (Chemical formula 1) and (Chemical formula 2) represents a polymerizable functional group, and CH ₂ ═CH—, CH ₂ ═CH—COO— , CH
_{2 = CH-COO-, CH 2} = CH -, - N = unsaturated bond such as C = O, or represents a functional group having a heterocyclic structure having distortion such as epoxy groups. Further, B in the above (Chemical Formula 1) and (Chemical Formula 2) is a linking group connecting the polymerizable functional group and the liquid crystal compound, and specifically, an alkyl chain (-(C
H _{2) n} -), an ester bond (-COO-), ether bond (-O-), a polyethylene glycol chain (-CH ₂ C
H ₂ O-), and a bonding group obtained by combining these bonding groups, and it is preferable that after the polymer wall 18 is produced, it easily moves in response to an electric field on the polymer wall 18. A linking group having a length having 6 or more bonds from to the rigid part of the liquid crystal molecule is particularly preferable.

LC ₁ represents a liquid crystal compound, which is a compound represented by the following (Chemical Formula 3), a cholesterol ring or a derivative thereof, or the like.

[0063]

Embedded image In the above (Chemical Formula 3), G is a polar group that causes dielectric anisotropy of liquid crystal and the like, and is —CN, —OCH ₃ , —F, —C.
l, -OCF _3, a benzene ring having a functional group such as -OCCl _3, cyclohexane ring, para-diphenyl ring, a phenyl cyclohexane ring, a terphenyl ring, a diphenyl cyclohexane ring. Further, in the above (Chemical Formula 3), E is a functional group that connects the functional group D and the polar group G, and is a single bond or -C.
_{H 2 -, - CH 2 CH} 2 -, - O -, - C≡C -, - CH
= CH- and the like. Furthermore, in the above (Chemical formula 3), D is
It is a functional group that binds to B in (Chemical Formula 1) or (Chemical Formula 2) and that influences the magnitude of dielectric anisotropy and refractive index anisotropy of liquid crystal molecules. , Paraphenyl ring, 1,10-diphenyl ring, 1,4-cyclohexane ring, 1,10-phenylcyclohexane ring and the like. In addition, LC ₂ includes rigid molecules such as a paraphenyl ring, a 1,10-diphenyl ring, a 1,4-cyclohexane ring, and a 1,10-phenylcyclohexane ring, and these molecules alone or these molecules are single bond, -CH ₂ CH ₂ -, -
CH = CH-, -C≡C-, -COO-, -N = CH
Molecules in which a plurality of the above-mentioned molecules are bonded with a linking group such as-, -O-, -N = N-, and -COS- can be used.

When the liquid crystal material used as the liquid crystal material in the liquid crystal device of the present invention has a positive dielectric anisotropy, the polar group G in the chemical formula 3 has a different dielectric constant. It is placed at such a position that the tropism Δε becomes positive, and specifically, the di- or tri-substituted benzene ring contained in the polar group G,
It is a structure containing a few substitution products. When the liquid crystal material used as the liquid crystal material in the device of the present invention has a negative dielectric anisotropy, the dielectric constant anisotropy Δε is defined as the position in the polar group of G in the above chemical formula. Is a position where N is negative, and specifically, is a structure containing a 4-substituted product, a 3,4,5-substituted product, a 3,4-substituted product or the like of the benzene ring contained in G. When there are a plurality of substituent groups of these polar groups in the same molecule, they do not have to be the same substituent groups. Further, in the above two cases, it is not necessary to use a single molecule, a plurality of polymerizable liquid crystal materials may be contained, and at least one kind of the compound may be contained. Further, the above compound does not need to exhibit liquid crystallinity by itself, and it is sufficient that the liquid crystallinity of the host liquid crystal material is not significantly deteriorated. In the present invention, the compound having the above structure alone is defined as a liquid crystalline polymer material even if it does not exhibit liquid crystallinity.

(Photopolymerizable material) As the photocurable resin, for example, acrylic acid and acrylate having a long-chain alkyl group of C3 or more or a benzene ring, more specifically, isobutyl acrylate, stearyl acrylate,
Lauryl acrylate, isoamyl acrylate, n-butyl methacrylate, n-lauryl methacrylate, tridecyl methacrylate, 2-ethylhexyl acrylate, n-stearyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-phenoxyethyl methacrylate, isobornyl acrylate,
Isobornylmethacrylate Further, in order to enhance the physical strength of the polymer, a polyfunctional resin having two or more functional groups, such as R
-684 (manufactured by Nippon Kayaku), bisphenol A dimethacrylate, bisphenol A diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetra Methylol methane tetraacrylate, neopentyl diacrylate, more preferably a halogenated, especially chlorinated, and fluorinated resin that reduces anchoring strength at the polymer-LC interface and is effective in lowering the voltage, such as 2 2.2.3.4.4.4-Hexafluorobutyl methacrylate, 2.2.3.4.4.4-Hexachlorobutyl methacrylate, 2.2.3.3-Tetrafluoropropyl methacrylate, 2.2.3 .3-Tetrachloropropyl Methacrylate, perfluorooctyl methacrylate, perchloropentyl methacrylate, perfluorooctyl ethyl acrylate,
It is perchlorooctylethyl acrylate.

(Liquid Crystal Material) The liquid crystal is an organic mixture that exhibits a liquid crystal state near room temperature, and includes nematic liquid crystal (including dual frequency driving liquid crystal and liquid crystal with dielectric anisotropy Δε <0) or A nematic liquid crystal to which a cholesteric liquid crystal is added is preferable in terms of characteristics. In this case, it is preferable that the chiral pitch is 10 μm or more, and if the chiral pitch is 10 μm or less, the liquid crystal molecules 20 are deviated from the alignment regulating force of the substrates 12 and 13.
Of the uniaxial optical compensation plate 26
Therefore, it becomes difficult to perform optical compensation. More preferably, a liquid crystal having excellent chemical reaction resistance is preferable because it is accompanied by a photopolymerization reaction when the liquid crystal display element 11 is manufactured. Specifically, it is a liquid crystal having a functional group such as a fluorine atom in the compound. Specifically, ZLI-4801-000, ZLI-4801
-001, ZLI-4792, ZLI-4427 (all manufactured by Merck & Co., Inc.) and the like.

In selecting a liquid crystal compound having a polymerizable functional group in the molecule from these liquid crystal materials, it is preferable from the viewpoint of compatibility that the respective portions exhibiting liquid crystallinity are similar. Especially, F and C, which have a unique chemical environment
Regarding the l-based liquid crystal material, it is preferable that the liquid crystal compound having a polymerizable functional group is also an F, Cl-based liquid crystal material.

The refractive index of the liquid crystal material is the refractive index n _o (ordinary light refractive index), n _e (extraordinary light refractive index) of the liquid crystal material constituting the liquid crystal layer, and the polymer material forming the wall structure. The relationship with the refractive index n _p is

[0069]

It is preferable that | ((n _e or n _o ) −n _p ) | ≦ 0.1. If the difference in the refractive index shown in the above (Equation 1) is outside the range of the (Equation 1), there is a mismatch in the refractive index between the liquid layer and the polymer material, and the display becomes rough. Moreover, the contrast is lowered.
A more preferable condition regarding the difference in the refractive index is a refractive index n.
_p is a value between the refractive index n _e and the refractive index n _o . When the refractive index n _p is within this range, even if the liquid crystal molecules 20 are driven by a voltage, the polymer wall 18
The difference between the refractive index of the liquid crystal material and the refractive index of the liquid crystal material is reduced, and the scattering phenomenon occurring at the interface between the liquid crystal material and the polymer material is extremely reduced.

(Mixing ratio of materials) The amount of the liquid crystalline polymer compound to be added must be such that the mixture of the compound, the liquid crystal material, the photopolymerization initiator and the photocurable resin can take a liquid crystal state. The amount of liquid crystallinity varies depending on the material. In the present invention, although not particularly limited, it is preferable that the amount of the liquid crystalline polymer compound added in the photocurable resin is 30 to 90% by weight. When it is 30% or less, the temperature range in which the mixture takes a liquid crystal state decreases, and the liquid crystal molecules 20 in the liquid crystal cell 11 which is the π cell of this embodiment cannot be sufficiently aligned between the substrates 12 and 13. If the added amount is 90% or more, the elastic modulus after curing of the liquid crystalline polymer material is low, and thus sufficient support force of the liquid crystal cell 11 against external force as described above cannot be obtained.

The weight ratio for mixing the liquid crystal material and the polymerizable compound (including the liquid crystal polymerizable compound) is preferably 50:50 to 97: 3 for liquid crystal: polymerizable compound, and more preferably 70:30 to 95. : 5. If the liquid crystal material is less than 50% of the weight of the mixture, the effect of the polymer wall 18 becomes excessive, the driving voltage required for the liquid crystal cell 11 increases remarkably, and the alignment regulating force of the substrates 12 and 13 is increased. The oriented liquid crystal regions 19 are reduced and the practicality is lost. further,
When the content of the liquid crystal material exceeds 97%, the polymer wall 18 is not sufficiently formed, and the physical strength is lowered, so that stable performance cannot be obtained.

Further, in the system in which the polymer wall is not formed, the polymer layer 27 is formed on the surface of the electrode substrate on the liquid crystal layer side, as shown in FIG. 15, instead of the polymer wall formed between both electrode substrates. However, in this case, the present inventors
The weight ratio of mixing the liquid crystal and the polymerizable compound (including the liquid crystalline polymer compound) is preferably 0.1 to 5% by weight based on the total amount of the liquid crystal and the photocurable resin in the photopolymerizable resin. I found it. This is because, in this case, it is not necessary to use a photomask, and when the photopolymerizable resin exceeds 5% by weight, a large number of polymer walls are formed in the pixel region and the driving voltage of the cell is significantly increased. Further, the scattering phenomenon due to the difference in refractive index between the liquid crystal and the polymer becomes remarkable, and the contrast is lowered. On the other hand, if the amount of the photo-curable resin added is less than 0.1% by weight, the liquid crystal region aligned along the alignment regulating force of the polymer on the substrate is reduced and the practicality is lost.

(Retardation: d.Δn) In the liquid crystal cell 11 of the present invention, since the liquid crystal region 19 has the same alignment state as that of a normal π cell, the optimum retardation and position of the liquid crystal cell 11 are The retardation of the retardation plate is the same as that of a normal π cell. A cell thickness d _1, the liquid crystal product d ₁ · △ n ₁ values between the effective refractive index anisotropy △ n _1, the green which is easily perceived by the human eye the light (lambda = 550 nm) in (d ₁・ △
When n ₁ / λ ₁ ) is an integral multiple of 1/2, the brightest display is obtained. Therefore, a value as close as possible to this condition is preferable. In particular, from the viewpoint of improving contrast and eliminating coloring, The product d ₁ · Δn ₁ is preferably 250 to 350 nm. In particular, since the liquid crystal display element of the present invention utilizes the light transmission effect by retardation, the retardation d ₁ · Δn ₁ = 275 nm near which the green color (550 nm) which is easily perceived by human eyes is most transmitted is the most. preferable. However, with the liquid crystal cell 11 alone, the viewing angle characteristics are bilaterally symmetric with respect to one direction of the liquid crystal molecular axis, and the viewing angle characteristics are not omnidirectional.

As a method for solving this problem, an optical compensation plate 26 composed of a uniaxial light compensation plate or a biaxial light compensation plate is provided between the polarizing plate 24 and the substrate 12 as shown in FIG. By installing in an optical configuration, the viewing angle characteristics can be converted into omnidirectional characteristics. In FIG. 2, with respect to the molecular axis of the liquid crystal molecule 20, that is, the major axis direction 50,
The polarization directions 51 and 52 of the pair of polarizing plates 24 and 25 form 45 °, respectively, and the polarization directions 51 and 52 are perpendicular to each other. In addition, the main axis direction 5 of the optical compensation plate 26
3 is defined to be perpendicular to the molecular axis direction 50. For this purpose, the value of the product d ₂ · Δn ₂ of the refractive index anisotropy Δn ₂ and the thickness d ₂ of the substrate having the optical phase compensation function is very important, and the difference (d It is preferable that ₁ · Δn ₁ −d ₂ · Δn ₂ ) is almost zero. Further, the optical axis of the substrate having the optical phase compensation function and the substrate 1 of the liquid crystal molecules 20
The orientation direction on 2 and 13 is important, and as shown in FIG. 2, it is preferable that the long axis of the liquid crystal molecule 20 and the optical axis of the uniaxial optical compensation plate 26 are located substantially at right angles to each other.

(Photopolymerization Initiator) As the photopolymerization initiator (or catalyst), Irgacure 184, 651, 907, Daro
Cure 1173, 1116, 2959 and the like can be used, and the mixing ratio is preferably 0.3 to 5% by weight based on the total amount of the liquid crystal and the polymerizable compound. The mixing ratio is 0.3%
In the following, the photopolymerization reaction does not sufficiently occur, and if it is 5% or more, the phase separation speed between the liquid crystal and the polymer material is too fast, and as a example, it becomes difficult to control the formation of the liquid crystal region 19 for each pixel 21. , The liquid crystal droplet becomes small and the driving voltage becomes high.

When plastic substrates are used as the substrates 12 and 13 of the liquid crystal cell 11, ultraviolet rays are absorbed by the substrates, so that polymerization hardly occurs. Therefore, it is preferable to use a photopolymerization initiator which has an absorption band in the visible light region and reacts in the visible light region. Specifically, Lucirin T
Examples include PO (manufactured by BASF), KYACURE DETX-S (manufactured by Nippon Kayaku), and CGI369 (manufactured by Ciba Geigy).

(Driving Method) The manufactured liquid crystal cell 11 is driven by simple matrix driving, a-Si TFT (thin film transistor formed of amorphous silicon), p-Si.
A TFT (thin film transistor formed of polysilicon), MIM (metal-insulating film-metal structure switch element), or the like can be driven by a driving method such as active driving in which each pixel 21 is used. In the present invention, the driving method is not particularly limited.

(Substrate material) The substrate 12, 13 is made of a transparent solid such as glass or a polymer film, and the non-transparent solid is a metal thin film when the present invention is applied to a reflective liquid crystal display device. A substrate formed as a film, a Si substrate, or the like can be used.

As the plastic substrate, a material having no absorption region for visible light is preferable, and PET (polyethylene terephthalate), acrylic polymer, polystyrene,
Polycarbonate or the like can be used.

Further, two kinds of these substrates can be combined to form a cell on a different kind of substrate, and two kinds of substrates having different kinds of different thickness can be used in combination regardless of the same kind and different kind.

Examples of the present invention will be shown below, but the present invention is not limited thereto.

(Embodiment 1) FIG. 3 is a process chart for explaining a method of manufacturing a liquid crystal display device of this embodiment. 1 and 3
See also. In step a1 in FIG. 3, the film thickness of ITO (a mixture of indium oxide and tin oxide) is 50 n.
m, the transparent electrodes 14 and 16 are formed on the glass substrates 12 and 13 having a thickness of 1.1 mm, and the alignment films 15 and 17 are formed by applying polyimide on the substrates 12 and 13 by spin coating. Rubbing treatment was performed using a nylon cloth. In step a2 of FIG. 3, by combining the two substrates 12 and 13 which have been subjected to the alignment treatment by the above rubbing treatment so that the alignment treatment directions are the same, and the cell thickness is maintained by a spacer having a size of 7 μm. , A pair of substrates 1
An empty cell in which 2 and 13 were sealed with a sealing material was formed.

In step a3 of FIG. 3, rectangular light shielding regions 31 shown in FIG. 4 are arranged in a matrix on the prepared empty cell, and light transmitting regions 32 are formed between the light shielding regions 31. The photomask 30 is placed in the empty cell so that the portion of the pixel 21 in FIG. 1 is shielded from light. On the other hand, in step a4 of FIG. 3, the mixture injected into the empty cell was treated with R-684.
(Nippon Kayaku Co., Ltd.) 0.10 g, styrene 0.05 g, 0.75 g of compound A shown in the following chemical formula 4,

[0084]

[Chemical 4]

Compound A Isobornyl acrylate 0.10 g, liquid crystal material E7
(Merck: Δn = 0.225: homogenization temperature 60.5
℃) 4g, and 0.025 of the photopolymerization initiator Irgacure 651
g was uniformly mixed (homogenization temperature: 40 ° C.).

In step a5 of FIG. 3, the mixture was capillary-injected into the empty cell. Then, in step a6, the following UV light irradiation is performed. Between the transparent electrodes 14 and 16
While applying a voltage of 4 V, a cell was installed at a position of 10 mW / cm ² below a high-pressure mercury lamp capable of obtaining parallel rays, the temperature of the cell was set to 100 ° C., and the cell was set from the photomask side to the cell. , UV light was irradiated for 10 minutes. At this time, the UV light is radiated to the cell as a pattern having a regularity in which the weak irradiation region as described above is spatially repeated. Next, the voltage is applied as it is, and then the cell is gradually cooled to 25 ° C., which is a temperature at which the liquid crystal transits to the nematic state, at a cooling rate of 10 ° C./hr, and further UV is continuously supplied for 3 minutes. Was irradiated to cure the resin. In this slow cooling process, the liquid crystal molecules 20 are
Due to the alignment regulating force of the substrates 12 and 13, the alignment becomes better than in the case where the substrate is not gradually cooled, and the display quality is further improved. After this, in step a7 in FIG. 3, the photomask was peeled from the cell.

When the manufactured cell was observed with a polarization microscope, as shown in FIG. 5, the liquid crystal region 19 according to the pattern of the light shielding region 31 and the light transmitting region 32 of the photomask 30 of FIG.
Had been formed. As shown in FIG. 5, picture element areas 21 having the same pattern as the pattern of the light shielding area 31 of the photomask 30 are formed in a matrix, and a plurality of liquid crystal areas 19 having substantially the same size as each picture element area 21 are formed. The polymer walls 18 were formed between the liquid crystal regions 19. In this cell, the liquid crystal region 21 had a structure similar to that of a conventional π cell in which the liquid crystal region 21 was bend-aligned when a voltage was applied as shown in the following comparative example. Furthermore, since the liquid crystal photo-curable resin is polymerized, the polymer wall 18 contains a liquid crystal polymer.

In step a8 of FIG. 3, the cell produced was
45 ° to the rubbing direction of the substrates 12 and 13, respectively
1 and the polarizing directions of the polarizing plates 24 and 25 shown in FIG. 1 are aligned so that they intersect each other at 90 °, and the polarizing plates 24 and 25 are attached to a cell to form a π-cell type. A liquid crystal display device was produced.

(Comparative Example 1) The liquid crystal cell 11 produced in Example 1 was used, and the material for producing the polymer wall 18, such as a photocurable resin, was omitted, and only the liquid crystal material used in Example 1 was placed in the empty cell. It injected and produced the cell. Example 1 was applied to the manufactured cell.
A polarizing plate was attached in the same manner as in 1. to produce a conventional π cell.

The electro-optical characteristics of the produced liquid crystal cell 11 of Example 1 are shown in FIG. 6 and Table 1 below. FIG. 6 is a graph showing the electro-optical characteristics of applied voltage-light transmittance of the liquid crystal cell 11 of Example 1. From FIG. 6 and Table 1, in the liquid crystal cell 11 of Example 1 of the present invention, the bend orientation was thermally stable even when the voltage was turned off, and Comparative Example 1 which was conventionally used.
The liquid crystal cell of Example 1 has at least the same or better electro-optical characteristics as the liquid crystal cell of Example 1, and when the liquid crystal cell 11 of the present example was pressed with a pen-shaped body, almost no color change was observed. That is, the polymer wall 1 is included in the liquid crystal cell 11 of this embodiment.
It has been found that since it has 8 innumerable, it can withstand external pressure such as pen pressure. In the case of Comparative Example 1 which does not have the polymer wall 18 of this example, display unevenness was caused.

[0091]

[Table 1]

Further, in order to examine the adhesion between the polymer wall 18 of the liquid crystal cell 11 of this embodiment and the substrates 12 and 13, a portion of the 20 mm square liquid crystal cell where only the polymer wall 18 and the liquid crystal region 19 exist. When it was cut out and one of the substrates was pulled, it did not peel off easily. On the other hand, in the liquid crystal cell of Comparative Example 1, since the polymer wall was not present in the liquid crystal cell, the substrates were peeled off from each other while cutting out a portion of 20 mm □ from the liquid crystal cell.

Further, the produced liquid crystal cell 11 of this example.
In addition, the uniaxial optical compensation plate 26 shown in FIG. 1 having a phase difference of 655 nm is attached between the polarizing plate 24 and the substrate 12 so that the optical axis of the compensation plate 26 is orthogonal to the molecular axis of liquid crystal. In addition, the viewing angle characteristics were measured. FIG. 7 shows the result. FIG. 7 is a graph showing the electro-optical characteristics of viewing angle and light transmittance. From FIG. 7, the optical compensation plate 2 which is the retardation plate is shown.
By installing 6, it is confirmed that the viewing angle characteristics of the optical compensation plate 26 of Example 1 are omnidirectional.

On the other hand, the electro-optical characteristics of the manufactured liquid crystal cell of Comparative Example 1 are shown in FIG. FIG. 8 is a graph showing the electro-optical characteristics of applied voltage and light transmittance of the liquid crystal cell of Comparative Example 1. As can be seen from FIG. 8, the liquid crystal cell of Comparative Example 1 changes from the spray alignment to the bend alignment only at a certain voltage. Furthermore, when the voltage of the liquid crystal cell of Comparative Example 1 was changed from the voltage-applied state to the voltage-unapplied state, the alignment state of the liquid crystal molecules gradually relaxed from the bend alignment to the spray alignment. Further, when the manufactured liquid crystal cell of Comparative Example 1 was pressed with a pen, display unevenness easily occurred in the peripheral portion of the portion pressed with the pen.

(Comparative Example 2) An empty cell was prepared in the same manner as in Example 1, the same mixture as in Example 1 was injected into the empty cell, and the same conditions as in Example 1 were applied without attaching the photomask to the cell. And U
V irradiation was carried out to produce a liquid crystal cell. The electro-optical characteristics of the produced liquid crystal cell are shown in Table 2 below. When the produced liquid crystal cell was observed with a polarization microscope, the polymer wall was embedded in the picture element, and as described above, the factor of lowering the contrast occurred.

[0096]

[Table 2]

(Examples 2 and 3, Comparative Examples 3, 4, and 5) The same cells as in Example 1 were used, and the applied voltage during ultraviolet exposure was 0 V (Comparative Example 3) and ± 1 V (Comparative Example 4). , ± 3 V (Example 2), ± 5 V (Example 3), and ± 25 V (Comparative Example 5), and each liquid crystal cell was manufactured in the same manner as in Example 1. The orientation state of the liquid crystal molecules was estimated from the electro-optical characteristics of the applied voltage and the light transmittance of each of the produced liquid crystal cells, and shown in Table 1 above. In Comparative Example 5, almost no change in transmittance due to voltage application was observed, and it is presumed that the alignment was vertical.

(Example 4) The same orientation operation as in Example 1 was performed using two acrylic plastic substrates each having the same electrodes as in Example 1 formed on the surface thereof. A spacer having a size of 7 μm was used in the same manner as in Example 1 to bond a pair of substrates to each other to fabricate a plastic substrate empty cell.
The plate thickness of the plastic substrate is 400 μm, and FIG. 9 shows an absorption curve showing the relationship between the incident wavelength and the light transmittance. The substrate partially blocks light having a wavelength of 350 nm or less. Further, the same photomask as in Example 1 was placed on the empty cell.

Further, in an empty cell, 0.10 g of R-684 (manufactured by Nippon Kayaku Co., Ltd.), 0.01 g of styrene, 0.75 g of the compound A, and 0.14 g of isobornyl acrylate.
Liquid crystal material E7 (manufactured by Merck) and 4 g of photoinitiator Luci
A mixture of 0.025 g of rin TPO (manufactured by BASF: having a maximum light absorption rate near a light wavelength of 400 nm) was vacuum-injected. Specifically, the inside of the cell is set to 100 Pa, the cell and the mixture are set to 30 ° C., and the injection is started. Immediately after starting the injection, the temperature of the substrate and the injection dish containing the mixture to be injected are raised to 60 ° C. and injection is performed.

Next, while applying a voltage of ± 5 V between the transparent electrodes of the pair of substrates, the liquid crystal cell of this example was applied to the liquid crystal cell of this example from the photomask side under the same ultraviolet irradiation intensity and conditions as in Example 1 at 100 ° C. The liquid crystal cell set to 1 was continuously irradiated with UV light for 10 minutes. Next, after slowly cooling the cell to 25 ° C,
The photomask was not moved and the ultraviolet rays were irradiated for another 3 minutes. Then, once the cell is heated to 100 ℃, it is 2 hours in 8 hours.
Gradually cooled to 5 ° C. It was a substantial retardation (Δn ₁ · d ₁ = 650 nm) of the manufactured cell.

A set of polarizing plates whose changing directions are orthogonal to each other and a retardation plate (Δn ₂ · d ₂ = 655 nm) 26 having an optical phase compensating function are formed in the manufactured cell in the same manner as in Example 1. As shown in 1, a cell was attached to the cell to prepare a polymer matrix-π cell of a plastic substrate. The electro-optical characteristics of the fabricated cell were almost the same as in Example 1.
As an example, an optical compensation plate 26 having the characteristics described below is arranged between the substrate 12 and the polarizing plate 24.

(Embodiment 5) A color filter substrate 40 as shown in FIG. 10 in which a picture element portion is a color filter 41 and a portion other than the picture element portion is a transmissive area 42, and a display electrode is provided in the picture element area 21. And the like, and the TFT substrate 45 having a black mask 44 made of a black resin material in a portion other than the pixel region 21 is subjected to the same alignment treatment as in Example 1, and It pasted on on the same conditions. Further, the same mixture as in Example 1 was vacuum-injected, and UV was injected from the color filter substrate side as in Example 1.
It was exposed to light to prepare a TFT-polymer matrix-π cell.

In this method, since the liquid crystal layer and the photomask, that is, the color filter substrate 40 are closer to each other by the thickness of the color filter substrate 40 than in the case of the first embodiment, the light is diffracted by the photomask into the pixel area 21. Polymer formation can be prevented. In particular, this is a manufacturing method by self-alignment, which is effective for a cell having a small pixel region 21. Moreover, in this method, the step of attaching the photomask of another component used in each of Examples 1 to 4 to the substrate can be omitted, so that the number of components can be reduced and the number of manufacturing steps can be reduced, thereby significantly reducing the cost. Can be achieved.

Example 6 Using the same cell as in Example 1, R-684 (manufactured by Nippon Kayaku Co., Ltd .: refractive index 1.5036) was used.
0.10 g, p-fluorostyrene (refractive index 1.515)
0.10 g, 0.30 g of the compound A, isobornyl acrylate (refractive index 1.474) 0.30 g, and perfluorooctyl acrylate (refractive index 1.334)
A liquid crystal cell was produced in the same manner as in Example 1 by using 0.20 g of the resin composition and further using the same liquid crystal material E7 as in Example 1. A pair of polarizing plates were attached to the produced liquid crystal cell in the same manner as in Example 1, and the electro-optical characteristics were measured. In the measurement of this example, in order to evaluate the magnitude of the scattering phenomenon at the interface between the liquid crystal and the polymer wall 18 in the picture element region 21, the lenses (2.7 ° and 27 °) having different converging angles were evaluated.
() Was used for the measurement. The larger the converging angle of the lens, the easier it is to collect the scattered light scattered from the liquid crystal cell, and the light transmittance ratio in the black state (saturated state) R = T ₂₇ ° /
It can be verified that the scattering phenomenon decreases as T _2.7 ° approaches 1. In this example, R = 1.1.

Only the resin composition is cured to form a polymer,
The refractive index of the polymer material was measured. As a result, the refractive index of the resin material is 1.49, and the ordinary refractive index n of the liquid crystal material is
The difference from _o (1.52) was 0.03. The results of these measurements are shown in Table 3 below.

[0106]

[Table 3]

The liquid crystal cells of Examples 1 to 6 have the following improved characteristics as compared with the conventional liquid crystal cells.

By using the polymer wall 18 that partially or entirely surrounds the liquid crystal region 19, it is possible to prevent the display unevenness of the liquid crystal cell 11 from being caused by an external force due to the use of the pen-shaped member. It can be used as a pen-input liquid crystal display element when used in combination with a terminal. In this case, a transparent position input film is mounted on the surface of the liquid crystal cell of each example, and the position input film is pressed by the pen-shaped member to input various instructions.

The orientation direction of the liquid crystal molecules 20 in the liquid crystal region 19 is such that the pixel regions 21 are aligned with respect to the center planes of the substrates 12 and 13.
The viewing angle characteristics are improved because the orientations are plane-symmetrical for each of them and the orientations are self-compensating. Furthermore, since the bend orientation is achieved, the response speed is fast.

The liquid crystal cell does not require the voltage application which was necessary for obtaining the initial alignment in the conventional π cell, and the driving method used in a normal liquid crystal cell can be used. From the improved characteristics described above, the liquid crystal cell of each of the embodiments has the above-described portable display element that requires pen input, a display element that may be viewed by multiple people from multiple directions, and a high-definition large-sized display element. It can be suitably used as a display element of a screen. Further, it can be used in the field where the current liquid crystal display element is used. For example, it can be used for a flat display device such as a personal computer, a liquid crystal television, a portable display using a film substrate, a glasses type display, and the like.

(Embodiment 7) FIG. 15 is a cross-sectional view of a liquid crystal cell 11 'of Embodiment 7 of the present invention, in which the same components as those in FIG. 1 are designated by the same reference numerals.

In Example 7, instead of the polymer wall formed between both electrode substrates, as shown in FIG. 15, a polymer coating the alignment films 15 and 17 on the surface of the electrode substrate on the liquid crystal layer side, respectively. The layer 27 is provided, and the pair of polymer layers 27 is provided.
The difference is that only the liquid crystal layer is present between.

The manufacturing method of the liquid crystal cell 11 'will be described below.

First, a transparent film having a thickness of 500 angstroms made of a mixture of indium oxide and tin oxide and having an ITO film thickness of 500 .ANG.
on the ITO films of the mm glass substrates 12 and 13,
Polyimide used as the liquid crystal alignment films 15 and 17 was applied by spin coating, and unidirectionally rubbed with a nylon cloth. The two rubbing-processed substrate portions are aligned so that the alignment treatment directions are the same.
A cell was constructed by combining the 7 sides facing each other and maintaining the cell thickness with a spacer of 7 μm.

A mixture containing 0.1 to 5% by weight of a liquid crystal compound having a polymerizable functional group in the molecule and a liquid crystal material in a crosslinked polymer of 0.1 to 5% by weight was uniformly mixed, and then a capillary was prepared. inject. Specifically, 0.1 g of the liquid crystalline polymer compound X of the following (Chemical Formula 5) and 0.02 of p-phenylstyrene are shown.
g, 9.88 g of liquid crystal material E7 (manufactured by Merck: Δn = 0.225: homogenizing temperature 60.5 ° C.), and photoinitiator I
A mixture of rgacure 651.04 g was injected by capillary after uniform mixing.

[0116]

Embedded image

Further, while applying a voltage of ± 4 V between the transparent electrode substrates, the cells injected with the mixture were irradiated with ultraviolet light at a temperature of 100 ° C. for 10 minutes under a high pressure mercury lamp at 10 mW / cm ^2. To separate the liquid crystal region and the polymer layer region into phases. After that, leave the applied voltage unchanged,
The cell was gradually cooled to a temperature of 25 ° C. at which the liquid crystal was in a nematic state at a cooling rate of 10 ° C./hr. Further, the resin in the polymer layer region was cured by irradiating ultraviolet rays continuously for 3 minutes. During this slow cooling process, the liquid crystal molecules are aligned along the alignment force of the substrate, and the display quality is improved.

Even when no voltage was applied, the liquid crystal region had a structure equivalent to the bend alignment when a voltage was applied in the conventional π cell shown in (Comparative Example 6) below. Further, since the liquid crystal photo-curable resin is polymerized, the polymer layer 27 contains a liquid crystal polymer, and the bend alignment is fixed.

Next, in the cell manufactured as described above,
45 with respect to the rubbing directions of the alignment films 15 and 17, respectively.
The polarizing plate 24 in the direction of 90 ° with respect to each other.
The polarizing plates 24 and 25 were attached to the upper and lower sides of the cell so that the polarization direction of 25 was aligned and a π-cell liquid crystal display device was produced. That is, a pair of polarizing plates whose polarization axes are orthogonal to each other are set such that one polarization axis is approximately 45 ° from the rubbing direction on the substrate.

The electro-optical characteristics of the cell thus manufactured are shown in FIG. It can be seen from FIG. 12 that the voltage application for the initial alignment, which was necessary in the conventional π cell, is unnecessary. Therefore, in Example 7 of the present invention, the bend orientation of the liquid crystal molecules was thermally stable even when the voltage was turned off, and the transmittance-applied voltage was lower than that of the following (Comparative Example 6) which was conventionally used. The electro-optical characteristics were comparable.

Further, a uniaxial optical compensating plate 26 having a phase difference of 655 nm is attached to the manufactured cell between the polarizing plate 24 and the substrate 12 so that the optical axis of the compensating plate 26 is orthogonal to the molecular axis of liquid crystal. As a result, it was confirmed that it had wide viewing angle characteristics.

Therefore, according to Example 7, in the voltage applied state (π cell orientation state), the liquid crystal layer and the polymer layer were prepared from the mixed liquid of 0.1 to 5% by weight of the crosslinked polymer and the liquid crystal material. Two
Since 7 is phase-separated, it is not necessary to apply a voltage for initial alignment, which was necessary in the conventional π cell, and liquid crystal molecules can be made to have a bend alignment in a stable state, and the driving voltage of the cell can be increased. The display characteristics such as contrast and contrast also become good.

In Example 7, the uniaxial optical compensating plate 26 was provided at least between the liquid crystal layer and one of the polarizing plates 24 so that the major axis of the liquid crystal molecule was orthogonal to the principal axis of the optical compensating plate 26. Although one sheet is installed, the uniaxial optical compensation plate 26 may be a biaxial optical compensation plate.

(Comparative Example 6) Using the cell prepared in the above (Example 7), only the liquid crystal material (the liquid crystal material used in Example 7) was injected into the cell to prepare a liquid crystal cell.
A polarizing plate was attached to this liquid crystal cell in the same manner as in (Example 7) to produce a conventional π cell.

The electro-optical characteristics of the cell thus manufactured are shown in FIG. As shown in FIG. 13, when a voltage is applied at a certain voltage for a certain period, liquid crystal molecules first enter a bend alignment state. Further, when the voltage applied state was changed to the non-voltage applied state, the spray orientation was relaxed, and it was found that the spray orientation was thermally stable when the voltage was not applied.

[0126]

As described above, according to the present invention, the conventional π
This is a cell-mode liquid crystal display device that is pseudo-solidified as a microcell in a polymer matrix. There is little change in cell thickness against external pressure, and there is a thickness for pen input, etc. Can be used in. Also, by having a polymer wall that surrounds the liquid crystal area, which is the area for each picture element of the liquid crystal layer, it is possible to prevent the display unevenness of the liquid crystal element from being caused by external force. It can be used as a display element. Further, even when no voltage is applied, the bend alignment state is in a stable state, and unlike the conventional cell, the initial alignment setting operation from the spray alignment to the bend spray alignment by voltage application is not required. Moreover, even when the voltage is switched from the voltage on to the voltage off, relaxation of the alignment from the bend alignment to the spray alignment does not occur. Furthermore, a high-speed response due to the bend orientation can be realized, and the viewing angle characteristics are omnidirectional by the uniaxial optical compensator or the biaxial optical compensator, which is extremely excellent.

Further, by separating the liquid crystal phase and the polymer phase from the mixed liquid of 0.1 to 5% by weight of the crosslinked polymer and the liquid crystal material, the polymer layer is formed on the surface of the electrode substrate on the liquid crystal layer side. Is formed, so that the substrate is accordingly strong.

By making use of the above characteristics, it can be used as a display device such as a large-sized high-definition liquid crystal display device and a portable information terminal device.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a liquid crystal cell 11 according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an optical configuration of the present embodiment.

3A to 3C are process diagrams illustrating a manufacturing process of the liquid crystal cell 11 of the present embodiment.

FIG. 4 is a plan view of a part of the photomask 30 used in Example 1.

5 is a plan view of a liquid crystal region-polymer wall produced in Example 1. FIG.

FIG. 6 is a graph showing the electro-optical characteristics of the liquid crystal cell manufactured in Example 1.

FIG. 7 is a graph for explaining viewing angle characteristics when the uniaxial optical characteristic compensation plate 26 is installed in the cell manufactured in Example 1.

8 is a graph illustrating electro-optical characteristics of Comparative Example 1. FIG.

FIG. 9 is a graph showing an absorption curve of the plastic substrate used in Example 4.

FIG. 10 is a plan view of a color filter substrate used in Example 5.

FIG. 11: TF with black mask used in Example 5
It is a top view of a T substrate.

12 is an electro-optical characteristic diagram of the cell manufactured in Example 7. FIG.

13 is an electro-optical characteristic diagram of the cell manufactured in Comparative Example 6. FIG.

FIG. 14 is a cross-sectional view showing the alignment of liquid crystal before and after voltage application in a π cell of a conventional example.

FIG. 15 is a sectional view of a liquid crystal cell 11 ′ according to a seventh embodiment of the present invention.

[Explanation of symbols]

 11, 11 'Liquid crystal cell 12, 13 Substrate 14, 16 Transparent electrode 15, 17 Alignment film 18 Polymer wall 19 Liquid crystal region 20 Liquid crystal molecule 21 Picture element 24, 25 Polarizing plate 26 Optical compensation plate (retardation plate) 27 Polymer Layer 30 Photomask 31 Light-shielding area 32 Light-transmitting area 40 Color filter substrate 41 Color filter 42 Transmission area 44 Black mask 45 TFT substrate 50 Molecular axis direction 51, 52 Polarization direction 53 Main axis direction

Front page continuation (72) Inventor Shuichi Kanzaki 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka

Claims (15)

[Claims] 1. A plurality of picture elements are arranged in a matrix,
A pair of electrode substrates each having an electrode formed on each surface, at least one surface of which is rubbed, and a wall formed between the pair of electrode substrates and having a unit wall structure repeated for each picture element A structure and a liquid crystal layer at least partially surrounded by the wall structure, the liquid crystal layer including a liquid crystal subregion formed between the pair of electrode substrates for each pixel, the liquid crystal being included in the liquid crystal layer. A liquid crystal display device comprising a liquid crystal layer in which liquid crystal molecules in a small region are oriented in plane symmetry with respect to a center plane between the electrode substrates and are in bend orientation. 2. The liquid crystal display element according to claim 1, wherein the pair of electrode substrates and the wall structure are in close contact with each other. 3. The liquid crystal display element according to claim 1, wherein a polymer liquid crystal material is contained in a material forming the wall structure. 4. A pair of polarizing plates whose polarizing axes are orthogonal to each other are arranged on each surface of the pair of electrode substrates, and one polarizing plate of the pair of polarizing plates has a polarizing axis of the electrode substrate. 2. The device is provided so as to be set at about 45 ° from the direction.
The liquid crystal display element described. 5. A retarder having a principal axis in a direction orthogonal to a major axis direction of the liquid crystal molecules and being equal to or substantially equal to a product d · Δn of a layer thickness d of the liquid crystal layer and an effective refractive index anisotropy Δn. The liquid crystal display device according to claim 4, wherein either a uniaxial optical compensation plate having a retardation value or a biaxial optical compensation plate is provided between the liquid crystal layer and either one of the polarizing plates. 6. The liquid crystal display element according to claim 1, wherein the material of at least one of the pair of electrode substrates is a polymer material that transmits visible light at at least a part of the wavelength. 7. The refractive indices n _o (ordinary light refractive index) and n _e (extraordinary light refractive index) of the liquid crystal material forming the liquid crystal layer, and the refractive index n _p of the polymer material forming the wall structure. Relationship is ｜
((N _e or n _o) -n _p) | liquid crystal display device according to claim 1, defined to be a ≦ 0.1. 8. A mixture of a liquid crystal material, a liquid crystal compound having a polymerizable functional group in the molecule, a polymerizable compound and a photopolymerization initiator, at least one of which is transparent, and at least one surface of which is subjected to a rubbing treatment. After injection between the pair of applied electrode substrates, a liquid crystal cell containing the pair of electrode substrates and the mixture is set in a matrix form on the pair of electrode substrates while applying at least one of an electric field and a magnetic field. The light having a regular spatial intensity is applied to the irradiation intensity corresponding to the plurality of picture elements, the liquid crystal and the polymer material are phase-separated by the photopolymerization reaction, and the unit wall structure is repeated for each picture element. At least a part of the polymer wall is surrounded by a liquid crystal material, and the liquid crystal molecules in the liquid crystal subregion included in the liquid crystal layer are substantially plane-symmetric with respect to the center plane between the electrode substrates. Orientation, and , A method for manufacturing a liquid crystal display element, which is formed so as to have bend alignment. 9. The method of manufacturing a liquid crystal display device according to claim 8, wherein the method of making the light intensity regular is a photomask. 10. The light in the liquid crystal cell containing the pair of electrode substrates and the mixture is irradiated with light having a regular spatial intensity in the irradiation intensity at a temperature equal to or higher than the homogenizing temperature of the liquid crystal material. The method for producing a liquid crystal display device according to claim 8, wherein the liquid crystal display device is photopolymerized and then slowly cooled while applying at least one of an electric field and a magnetic field. 11. The method for manufacturing a liquid crystal display device according to claim 10, wherein the liquid crystal cell is irradiated again with light after the slow cooling. 12. A liquid crystal display device in which a liquid crystal layer and a polymer layer are sandwiched between a pair of electrode substrates, and liquid crystal molecules of the liquid crystal layer are bend-aligned with the center plane between the electrode substrates being approximately plane symmetry. A liquid crystal display device, wherein the liquid crystal layer and the polymer layer are phase-separated from a liquid mixture of at least 0.1 to 5% by weight of a crosslinked polymer and a liquid crystal material. 13. The liquid crystal compound having a polymerizable functional group is contained in the molecule in the crosslinked polymer.
The liquid crystal display element described. 14. A pair of polarizing plates whose polarization axes are orthogonal to each other are disposed on each surface of the pair of electrode substrates, and one polarizing plate of the pair of polarizing plates has a polarizing axis of the electrode substrate. Direction of the liquid crystal molecules in the major axis direction of the liquid crystal layer between the liquid crystal layer and one of the polarizing plates. 13. The liquid crystal display device according to claim 12, wherein at least one optical compensation plate is installed so that the principal axes of the optical compensation plate and the optical compensation plate are orthogonal to each other. 15. A method of manufacturing a liquid crystal display device, wherein a liquid crystal layer and a polymer layer are sandwiched between a pair of electrode substrates, and liquid crystal molecules of the liquid crystal layer are bend-aligned with a center plane between the electrode substrates being substantially plane symmetric. A mixture of a polymerizable compound and a liquid crystal material containing at least 0.1 to 5% by weight of a liquid crystal compound having a polymerizable functional group in the molecule in a crosslinked polymer, at least one of which is transparent. After being injected between the certain electrode substrates, the bend alignment of the liquid crystal molecules is stabilized while applying at least one of an electric field and a magnetic field, and light or thermal energy is added to the mixture to form the liquid crystal phase and the polymer phase. A method of manufacturing a liquid crystal display device, which comprises a step of phase separation.