JPH08334757A - Liquid crystal display device, polarization phase difference composite film and their production - Google Patents

Abstract

PURPOSE: To provide a liquid crystal display device of a thin type with which the production is easy, a thin polarization phase difference composite film used for production of this liquid crystal display device and a process for producing such device and film. CONSTITUTION: This liquid crystal display device has a liquid crystal layer 7 and polarization thin films 1 held between substrates 3 having electrodes 4 and is constituted by joining the polarization thin films 1 having a film thickness of >=1nm to <=5μm on the substrates via adhesive layers. The polarization phase difference composite film is formed by laminating the polarization thin film having a film thickness of >=1nm to <=5μm on the surface on one side of the phase difference film. The liquid crystal display device is constituted by arranging the polarization phase difference composite film described above on at least one inner or outer side of the substrate by directing the surface not formed with the polarization thin films toward the liquid crystal layer side. This process for producing the liquid crystal display device comprises forming the polarization thin films on the base materials having the oriented films of a fluororesin on the surfaces, then transferring the polarization thin films onto the base materials of the liquid crystal display device. This process for producing the polarization phase difference composite film comprises forming the polarization thin films on the base materials having the oriented films of the fluororesin on the surfaces, then transferring the polarization thin films onto the phase difference film.

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, a polarization retardation composite film and a method for manufacturing them. More specifically, the present invention relates to a thin liquid crystal display device, a polarizing element and a retardation film used for the liquid crystal display device, and manufacturing methods thereof.

[0002]

2. Description of the Related Art Polarizing elements are widely used as indispensable elements for liquid crystal display devices. Currently, a polarizing element is manufactured by adsorbing iodine or a dichroic dye material on a stretched and oriented polyvinyl alcohol (hereinafter sometimes referred to as PVA) film or a derivative film thereof. These stretched films are usually used by sticking a protective film such as a cellulose derivative on both sides.

The most basic structure of the liquid crystal display device is constituted by arranging these polarizing elements on both sides of the liquid crystal cell. Generally, between a pair of transparent electrode substrates having electrodes, liquid crystal molecules having a positive dielectric anisotropy,
In the state where no voltage is applied, the structure is such that the molecular long axis is substantially parallel to the substrate and the long molecular axis is twisted about 90 ° or more and 270 ° or less around a spiral axis perpendicular to the substrate. Polarizing elements are arranged on both outer sides of the liquid crystal cell.
At this time, since the polarization directions of the two polarizing elements are arranged substantially parallel to the molecular long axes of the liquid crystal molecules on the substrates of the liquid crystal cells which are in contact with each other, the polarization directions of the two polarizing elements are also 90 ° or more and 270 or more. It is arranged at an angle that is almost the same as the twist angle of less than °. In particular, when the twist angle is 90 degrees, it is called a twist nematic (hereinafter sometimes referred to as TN) type, and when used in combination with a liquid crystal cell substrate having a film transistor, it is used for a high-performance liquid crystal display element. The cases are increasing.

On the other hand, when the twist angle is larger than 90 degrees,
In particular, when twisting about 180 to 270 degrees, super twist nematic (hereinafter sometimes referred to as STN).
Type, which has a steep voltage threshold and is used for displaying a large capacity by a simple matrix driving method. In this method, the liquid crystal in the cell exhibits a high refractive index in a specific direction in the plane of the cell (birefringence) in the twisted alignment state, so that light that is incident vertically on the liquid crystal cell surface Phase difference occurs. For this reason, the linearly polarized light that has entered the cell becomes elliptically polarized light, and it is not possible to completely turn on / off the light with the polarizing film on the output side, and it is colored to make black and white display and color display difficult. For this reason, in many cases, a polymer film called a retardation film is sandwiched between a liquid crystal cell and a polarizing element to cancel the phase difference generated in the liquid crystal cell to convert elliptically polarized light into linearly polarized light. On the other hand, retardation films in which the refractive index in the thickness direction of the film is controlled have been widely used in order to widen the viewing angle of liquid crystal display devices. Such a retardation film is manufactured by stretching a polymer film such as polycarbonate or polyester. Such a film is attached to a polarizing element to form one polarization retardation composite film, which is attached to a liquid crystal display device for use.

In recent years, with the widespread use of small portable information devices such as card devices, the liquid crystal display devices have been made thinner, and the thickness of the polarizing element and the retardation film is also reduced to be displayed. It is preferable to reduce the thickness of the entire device panel. On the other hand, there is a remarkable tendency to reduce the production cost of the liquid crystal display device to lower the price and expand the applications. Therefore, it is desired to easily manufacture a thin liquid crystal display device.

The current polarizing element uses a uniaxially oriented film manufactured by a stretching technique and is sandwiched by protective films. An adhesive layer for bonding is present between the polarizing layer and the protective layer. Furthermore, an adhesive layer for sticking the polarizing element, which is this laminated film, to a liquid crystal cell is also required.
Therefore, a typical polarizing element has a thickness of at least 120
It reaches the μm, and the total of the two used normally is 0.24mm.
The above thickness was reached, which was an obstacle to thinning. Further, since there are many bonding steps, there is a problem that the manufacturing is complicated and the cost is slightly high. On the other hand, when a retardation film is used, it is further laminated with a retardation film and laminated as a polarization retardation composite film. There are many adhesive layers for bonding between the polarizing element, the protective layer, and the retardation film. Therefore, the thickness of a general polarization phase difference composite film reaches at least 250 μm, and the total thickness of two sheets that are normally used reaches 0.5 mm or more, which is an obstacle to thinning.

As a method of making the liquid crystal display element thin,
A method is known in which a thin polarizing element is directly manufactured on a substrate sandwiching a liquid crystal layer. Imaseki et al. Align organic molecules such as diacetylene on the gas-liquid interface and copy them onto the substrate and then polymerize them, or deposit the organic molecules onto the rubbed substrate and then polymerize them. 100
A polarizing element having a wavelength of 10 nm is used in a liquid crystal display device without an adhesive layer or a protective layer for bonding (JP-A-3-1053).
19 and US Pat. No. 5,235,449). Although the target liquid crystal display device can be manufactured by this method, the operation of copying the organic molecules at the gas-liquid interface onto the substrate takes time because the monomolecular film is laminated, and the productivity is low. In addition, when a device such as a thin film transistor that is susceptible to static electricity is formed on the substrate, rubbing the substrate is not preferable.

On the other hand, J. C. Wittmann et al. Have shown that an oriented PTFE thin film can be obtained by rubbing a polytetrafluoroethylene (hereinafter sometimes referred to as PTFE) on a glass substrate while applying pressure while heating. It has been reported that alkanes, liquid crystal molecules, polymers, oligomers, inorganic salts, and the like can be aligned by using this as an alignment film [NATURE (Vol. 352, 414, 199).
1 year)]. Using this technique, a uniaxially oriented molecular thin film useful as a polarizing element can be produced.

As described above, there has not been known a thin liquid crystal display device in which the polarizing element to be used has a thin wall, has a small number of assembling steps, and is easy to manufacture. On the other hand, in the case of the STN type, it is necessary to reduce the total thickness including the retardation film, but a thin film which is suitable for this and a simple polarization retardation composite film with a small number of laminations is conventionally known. Didn't. Further, a thin liquid crystal display device using such a thin polarization retardation composite film has not been known.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thin liquid crystal display device which is easy to manufacture, a thin polarization retardation composite film which can be used for manufacturing the liquid crystal display device, and a manufacturing method thereof. It is in.

[0011]

The inventors of the present invention have reached the present invention as a result of extensive studies to solve the above problems. That is, the present invention relates to [1] a liquid crystal layer sandwiched between substrates having electrodes and a liquid crystal display device having a polarizing thin film, in which a polarizing thin film having a film thickness of 1 nm or more and 5 μm or less is bonded via an adhesive layer. The present invention relates to a liquid crystal display device. The present invention also relates to [2] a polarization retardation composite film in which a polarizing thin film having a film thickness of 1 nm or more and 5 μm or less is laminated on one surface of a retardation film. The present invention also provides [3] a liquid crystal molecule having a positive dielectric anisotropy, which is sandwiched between substrates having electrodes, whose major axis is substantially parallel to the substrate when no voltage is applied, and In a liquid crystal display device having a polarizing thin film, a liquid crystal layer configured to have a twisted structure in which a molecular long axis is twisted about 90 ° or more and 270 ° or less around a spiral axis substantially perpendicular to a substrate, The invention relates to a liquid crystal display device in which the polarization retardation composite film according to [2] is arranged on at least one side of a substrate so that the surface having no polarizing thin film faces the liquid crystal layer side. Further, according to the present invention, [4] having a positive dielectric constant anisotropy sandwiched between substrates having electrodes, the long axis of liquid crystal molecules being substantially parallel to the substrate when no voltage is applied, and the liquid crystal The molecular long axis is approximately 9 around the spiral axis, which is almost perpendicular to the substrate.
A liquid crystal display device having a polarizing thin film and a liquid crystal layer configured to have a twisted structure between 0 ° and 270 °, and the polarizing phase difference composite film according to claim 5 is polarized on both outsides thereof. The present invention relates to a liquid crystal display device in which a surface without a thin film is arranged so as to face the liquid crystal layer side. Further, the present invention [5] has a positive dielectric anisotropy, and when a voltage is not applied, the long axis of the liquid crystal molecule is substantially parallel to the substrate, and the long axis of the liquid crystal molecule is substantially perpendicular to the substrate. Around 9 around the spiral axis
In a liquid crystal display device having a liquid crystal layer configured to have a twisted structure between 0 ° and 270 ° and a polarizing thin film, at least one of substrates having electrodes sandwiching the liquid crystal layer is claimed. 5. The polarization retardation composite film according to 5, wherein the polarization retardation composite film is arranged so that the surface without the polarization thin film faces the liquid crystal layer side. The present invention also [6] forms a polarizing thin film on a substrate having a fluorine-based resin alignment film on its surface, and then transfers the polarizing thin film onto the substrate in a liquid crystal display device [1],
The present invention relates to the method for manufacturing a liquid crystal display device according to [3], [4] or [5]. Further, according to the present invention, [7] a polarizing thin film is formed on a substrate having a fluorine-based resin alignment film on its surface, and then the polarizing thin film is transferred onto a retardation film. The present invention relates to a method for manufacturing a retardation composite film. Furthermore, the present invention provides a liquid crystal display device comprising a liquid crystal layer sandwiched between substrates having an electrode [8], a polarizing thin film, and a fluororesin alignment film, and a polarizing thin film having a film thickness of 1 nm or more and 5 μm or less on the substrate. Liquid crystal having a function of aligning the liquid crystal of the liquid crystal layer, wherein the fluorine-based resin alignment film is bonded to the polarizing thin film, and the fluorine-based resin alignment film is bonded to the polarizing thin film. The present invention relates to a display device.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. In the present invention, a polarizing book film is used as a polarizing element forming a liquid crystal display device. The polarizing thin film used in the present invention is preferably formed on the fluororesin alignment film, but may be manufactured by other methods.

The fluorine-based resin alignment film can be prepared by a known method, but a highly aligned film can be obtained by using the method described in US Pat. No. 5,180,470. Specifically, it can be prepared by rubbing a fluorinated resin mass on the base material under pressure while applying heat.

The fluorine-based resin used for the alignment film is polytetrafluoroethylene (hereinafter sometimes referred to as PTFE), polytrifluoroethylene, polyvinylidene fluoride (hereinafter sometimes referred to as PVDF). Examples thereof include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (hereinafter referred to as PFA), tetrafluoroethylene-ethylene copolymer (hereinafter referred to as ETFE), and the like. PTFE is preferred.

The heating temperature of the base material at this time depends on the type of the base material to be rubbed with the resin, but it is lower than the decomposition temperature of the resin, preferably 100 ° C. or higher and 350 ° C. or higher. Resin is PTFE
When the base material to be rubbed is glass, it is preferably 130 ° C or higher and 340 ° C or lower, more preferably 250 ° C.
Or more and 340 ° C or less, particularly preferably 300 ° C or more and 340
It is below ℃.

The pressure can be appropriately selected depending on the type of the substrate to be rubbed with the resin. When the resin is PTFE and the base material to be rubbed is glass, 0.5 kgf / cm ² or more and 40 kgf or more are required to obtain a uniform alignment film having excellent alignment characteristics.
/ Cm ² or less is preferable and 5 kgf / cm ² or more and 20 k
It is more preferably gf / cm ² or less.

The rubbing speed can be appropriately selected depending on the type of the resin and the rubbing base material. When the resin is PTFE and the base material to be rubbed is glass, in order to obtain an alignment film that is uniform and has excellent alignment characteristics, it is preferably 0.01 cm / sec or more and 10 cm / sec or less, and 0.01 cm / sec or more. Particularly preferably, it is 0.5 cm / sec or less.

If the thickness of the fluorine resin alignment film is too thin, the polarizing thin film deposited on it will not be aligned. On the other hand, when the thickness of the alignment film is too thick, absorption in the visible region becomes large and the transmittance of the polarizing element is lowered. Therefore, the thickness of the fluorine-based resin alignment film is preferably 1 nm to 1 μm, more preferably 1 nm to 0.2 μm, and particularly preferably 1 nm to
It is 50 nm.

The base material for forming the fluorine-based resin alignment film includes
Materials that can withstand the temperature and pressure of the rubbing operation can be used. For example, glass, transparent electrode [I
TO (Indium-Tin Oxide), In ₂ O
₃ , SnO ₂ etc. coated glass, heat resistant polymer material [polyether sulfone, polystyrene, polymethylmethacrylate, polycarbonate etc.], heat resistant polymer material coated with transparent electrode on one side, metal plate, metal Rolls etc. can be used. In this case, a material having a surface plated with a metal such as Ni can be used as the metal material. However, since it is particularly preferable to rub the PTFE at a temperature of 300 ° C. or higher and 340 ° C. or lower in terms of orientation of the obtained polarizing thin film,
In this case, the base material for rubbing the fluorine-based alignment film is 300 ° C.
It is preferable that it can withstand the above heat sufficiently. As such a substrate, glass, a transparent electrode [ITO (In
_{dium-Tin Oxide), In 2} O 3, SnO
₂ etc.], glass, metal plate, metal roll, etc. In the case of a metal material, a material whose surface is plated with a metal such as Ni can be used, but it is preferable that the underlying material to be plated also sufficiently withstand heat of 300 ° C. or higher.

The polarizing thin film in the present invention can be obtained by forming a dichroic dye material alone or a mixture with a binder material on an alignment film of a fluororesin. The dichroic dye material used in the present invention has an aspect ratio (length of molecular major axis / length of molecular minor axis) of preferably 2 or more, more preferably 3 or more. The angle is within 20 °, the ratio of the absorbance at the maximum absorption wavelength in the long axis direction of the dye molecule to the absorbance in the short axis direction of the molecule is preferably 5 or more, more preferably 8 or more, and particularly preferably 10 or more. Dye, if any
Any pigment can be used. In particular, among dichroic dye materials used in conventional dye-based polarizing films and guest-host type liquid crystal displays, a method of dissolving in nematic liquid crystal and placing in a liquid crystal cell for alignment, stretched PVA or its derivative film is used. When the dye is oriented by an adsorption method or the like, the maximum value of the ratio between the absorbance in the orientation direction at a specific absorption wavelength and the absorbance in the direction orthogonal thereto is preferably 5 or more, more preferably 8 or more, particularly preferably A material having a ratio of 10 or more is preferably used. In addition, a colored polymer material generally known as a conjugated polymer can also be used.

Known as dichroic dye materials for guest-host type liquid crystal displays are merocyanine type, styryl type, azomethine type, azo type, quinone type, quinophthalone type, perylene type, indigo type, tetrazine type and the like. Azo-based and anthraquinone-based dichroic dye materials that are practically used for their properties are preferable. Particularly, azo dyes include disazo dyes and trisazo dyes. On the other hand, in the dichroic dye material used for the polarizing film, a polyazo dye,
Anthraquinone dyes are exemplified. Examples of the conjugated polymer include polydiacetylene derivatives [1,6-di (N-carbazolyl) -2,4-hexadiyne and the like].

However, since it is necessary to uniaxially orientate these dichroic dye materials on the fluorine-based resin alignment film, the dichroic dye material is selected so that a high orientation can be obtained according to the method for producing the film. Need to be used. Specific examples of the azo dye include those shown in Table 1 below, but D1, D6, and D10 are preferable, and D10 is particularly preferable, from the viewpoint of orientation of the obtained thin film.

[0023]

[Table 1]

The thickness of the polarizing thin film depends on the dichroism of the dichroic dye material, the molar extinction coefficient, and the degree of orientation of the dichroic dye material in the film, but a uniform thin film without pinholes is required. From the viewpoint of formation, it is preferable that the thickness is thick, and in order to obtain a high degree of orientation, it is preferable that the thickness is thin. On the other hand, if it is too thin, the single element transmittance is too large, and sufficient performance as a polarizing element cannot be obtained. Therefore, the film thickness is preferably 5 μm or less, more preferably 1 nm or more and 5 μm or less, and further preferably 5 nm or more and 1 μm.
m or less, particularly preferably 10 nm or more and 0.5 μm or less. The dye content of the polarizing thin film depends on the type of dichroic dye material, but is preferably 1 wt% or more and 100 wt% or less, and more preferably 5 wt% or more and 100 wt%.
It is particularly preferably 10 wt% or more and 100 wt% or less. The polarizing thin film has a thickness of 400 nm to 800 nm.
Has an absorption peak at a wavelength of 5 and the dichroic ratio at the absorption peak wavelength is 5
It is preferably at least above, more preferably at least 10 and particularly preferably at least 25. Furthermore, it is preferable that the simple substance transmittance is 35% or more and 80% or less.

Examples of the method for producing the polarizing thin film include vapor deposition of a dichroic dye material, application of a molten dichroic dye material, application of a dichroic dye solution, etc. on a fluorine-based resin alignment film.
Among these methods, vapor deposition is the most preferable in terms of film thickness control and degree of orientation. In the case of vapor deposition, the dichroic dye material used is one that sublimes without being decomposed by heating. Also,
The polarizing thin film may be a film in which a dichroic dye material is dispersed in a binder material. Examples of the manufacturing method in this case include applying a molten mixture of a dichroic dye material and a binder material, applying a mixed solution of the dichroic dye material and a binder material, and the like. In the case of a polydiacetylene derivative, a method in which monomer molecules are deposited on an alignment film such as a fluorine resin alignment film and then polymerized is preferable. Vapor deposition is preferred as the deposition method. When it is prepared by vapor deposition, the diacetylene derivative monomer molecules are heated under vacuum at a decomposition temperature or lower to be sublimated and deposited on the substrate. The deposited monomer molecules are converted into a polydiacetylene film by polymerization, and this process can be performed by ultraviolet light, heat, radiation, electron beams, x-rays, etc., but since it can be performed easily, use ultraviolet light or heat. Is preferred, and it is particularly preferred to use ultraviolet light.

When the dichroic dye material and the binder material are used, the material used as the binder is transparent to visible light and can be melted together with the dichroic dye material or dissolved in water or a solvent. Good. From the viewpoint of film-forming property, a polymer compound is preferably used as the binder material. Specific examples include polyvinyl alcohol, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyethylene, polypropylene, and their copolymers or derivatives. Of these, polyvinyl alcohol, polycarbonate, polymethylmethacrylate, and polyethylene are preferable. The proportion of the binder material in the polarizing thin film according to the present invention depends on the types of the dichroic dye material and the binder material, but is usually 99 wt% or less, preferably 95 wt% or less,
More preferably, it is 90 wt% or less.

The purity required for the dichroic dye material or conjugated polymer used depends on the type of impurities. Depending on the type of impurities, the orientation may not be lowered even if the purity is considerably lowered, but it is generally preferable that the purity is high. Depending on the type of impurities, the purity is preferably 90
It is not less than 100% by weight, more preferably not less than 95% by weight and not more than 100% by weight, particularly preferably not less than 99% by weight and not more than 100% by weight.

Next, referring to FIG. 1, FIG. 2, FIG. 3 and FIG.
The present invention will be described in more detail. Electrode 4 in the present invention
Is usually ITO (Indium-Tin Oxid)
e), transparent electrodes such as In ₂ O ₃ and SnO ₂ are used. An appropriate lead wire is connected to the electrode 4 and is connected to an external drive circuit. It is particularly useful to form a thin film transistor circuit (commonly called a TFT) formed on a liquid crystal cell as a part of the external drive circuit because a display element with extremely high performance can be obtained. The two liquid crystal cell substrates 3 are held at a predetermined interval via a spacer 6. As the spacer, beads, fibers, or a film-shaped insulating material having a predetermined diameter or thickness can be used. Specific examples thereof include silica, alumina, and polymer substances (polystyrene etc.). These spacers 6 can be sandwiched between two liquid crystal cell substrates 3, and the periphery can be sealed with, for example, an epoxy adhesive or the like, and then liquid crystal can be enclosed. _And usually for example 1, 3, the configuration of FIG. 4, the liquid crystal layer 7 side of the electrode 4 is placed a liquid crystal alignment layer 5 of insulating. At this time, when the liquid crystal alignment control film 5 has a sufficient insulating property by itself, only the alignment film is necessary.
An insulating layer is provided under the liquid crystal orientation control film 5 if necessary,
Both of them may be an insulating alignment film. Further _{, when the} polarization book film 1 and the fluororesin alignment film 2 have the function of the liquid crystal alignment control film, the liquid crystal alignment control film 5 may be omitted as shown in FIG.

As the liquid crystal alignment control film 5, known materials such as organic materials, inorganic materials, low molecular weight compounds and high molecular materials can be used. As the polymer compound, for example, polyimide, polyamide, polyamideimide, polyvinyl alcohol,
Polystyrene, polyester, polyester imide, various photoresists and the like can be used as necessary. In addition, these polymer substances can achieve alignment of liquid crystal molecules by performing a so-called rubbing treatment in which the surface of these films is unidirectionally rubbed with gauze or acetate flocking cloth as necessary. it can. As the insulating film, for example, titanium oxide, aluminum oxide, zirconium oxide, silicon oxide, silicon nitride, or the like can be used. As a method for forming the liquid crystal orientation control film 5 and the insulating film, if necessary,
An optimum method can be used depending on the substances used. For example, in the case of a polymer substance, the polymer substance or its precursor can be applied by a method such as a screen printing method, a spinner coating method, or a dipping method after being dissolved in a solvent capable of dissolving those materials. . In the case of an inorganic substance, a dipping method, a vapor deposition method, an oblique vapor deposition method or the like can be used. The thickness of these insulating alignment films is not particularly limited, but is preferably 1 nm to 2 μm, more preferably 2 nm to 100 nm.

Known materials can be used for the liquid crystal cell substrate 3, and examples of such materials include glass and polymer materials _. Examples of the polymer material include polyether sulfone, polystyrene, polymethylmethacrylate, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polybutylene terephthalate, cellulose and derivatives thereof. Among these, glass, polyether sulfone, polymethylmethacrylate, polycarbonate and polyethylene terephthalate are preferable.

In the present invention, when the retardation film 9 is not used, the polarizing thin film 1 is bonded to the liquid crystal layer 7 side or outside of the liquid crystal cell substrate 3 to form a liquid crystal display element. After the polarizing thin film 1 is once formed on the base material having the fluorine-based resin alignment film 2, the adhesive layer 8 is attached to the surface of the liquid crystal cell substrate 3, and the polarizing thin film 1 on the base material is attached and peeled off. Methods of transfer can be used. In this case, the fluorine-based resin alignment film 2 and the polarizing thin film 1 may be bonded to the side having the electrode 4 as shown in FIG. 2, or the reverse as shown in FIG. When it is necessary to provide the polarizing thin film 1 inside the liquid crystal cell for the purpose of giving the function of aligning the liquid crystal to the fluorine-based resin alignment film 2, it is bonded to the side having the electrode 4 as shown in FIG. . Alternatively, the polarizing thin film 1 may be once transferred onto the liquid crystal cell substrate 3, and a necessary thin film including the electrode 4 may be further laminated thereon. Examples of such layers include color filters and overcoats.

The material of the adhesive layer 8 is transparent and stable, and it is necessary to use a material that does not react with or dissolve the material of the polarizing thin film 1. You can choose. As such materials, natural rubber, styrene-diene block copolymer system, styrene-butadiene rubber system, polyisobutylene system, recycled rubber system, ethylene-vinyl acetate copolymer system,
Acrylic, vinyl acetate copolymer, silicone, polyvinyl alkyl ether, epoxy, acrylic-
Examples thereof include those known as epoxy-based adhesive materials and adhesive materials. Among these materials, those having the property of being cured to a more stable material by heat or light are preferable. It is more preferable to use a photocurable material. Examples of such a material include those known as acrylic and acrylic-epoxy photocurable materials. For the photo-curable material, after the polarizing thin film 1 is once formed on the base material, a photo-curable adhesive is attached to the surface of the liquid crystal cell substrate 3 and the polarizing thin film on the base material is attached to the adhesive to light the light. A method of transferring by curing by irradiating to cure the adhesive and then transferring is preferably used.

When the polarizing thin film 1 is formed on the surface of the liquid crystal cell substrate 3 having the electrode 4, the polarizing thin film may be used as an alignment control film of liquid crystal in some cases. For example, when the polarizing thin film 1 is formed by being transferred to the surface of the liquid crystal cell substrate 3 having the transparent electrode as illustrated in FIG. 2, the fluororesin alignment film 2 may also be formed depending on the type of the base material of the fluororesin alignment film. Since they are also transferred together, there is a fluorine-based resin alignment film 2 on the surface of the polarizing thin film 1, and this works as an alignment control film for liquid crystals. Specifically, it is preferable to use glass or metal as the base material of the fluorine-based resin alignment film, but it is more preferable to use glass as the base material. However, since a pinhole may be generated in the fluororesin alignment film 2 and the polarization thin film 1 may be dissolved in the liquid crystal layer 7 from the pinhole, the surface of the polarization thin film 1 below the fluororesin alignment film 2 may be It is also practiced to use a material that does not dissolve in the liquid crystal used. Specifically, a conjugated polymer material such as a polydiacetylene derivative is preferably used. If the dichroic dye material forming the polarizing thin film dissolves in the liquid crystal used, a thin film that does not dissolve in the liquid crystal used and is uniaxially oriented due to the influence of the fluororesin alignment film 2 is formed. This also makes it possible to control the alignment of the liquid crystal. Materials for such thin films include polyethylene and P
TFE, nylon, polyester, aromatic polyimide,
Examples thereof include transparent polymer materials such as aromatic polyamide, polyamide imide, polyvinyl alcohol, polystyrene, polyester imide, and inorganic materials, such as PTFE,
Nylon, polyester and aromatic polyimide are preferable, and PTFE is particularly preferable.

The polarization retardation composite film of the present invention can be obtained by laminating the polarizing thin film 1 on the retardation film. The polarizing thin film 1 is formed directly on the retardation film 9 or formed on another substrate and then transferred. If it is transferred,
Method of transferring by strongly pressing against the retardation film 9 or pressing while heating, adhesive layer 8 on the surface
An example of such a method is to transfer the retardation film 9 attached with the tape by peeling it off. When the polarizing thin film 1 is laminated on the retardation film 9, the polarization axis of the polarizing thin film 1 and the optical axis of the retardation film 9 (the direction having the highest refractive index in the plane,
The normal stretching direction) is shifted to a predetermined angle. Since the magnitude of the angle varies depending on the liquid crystal used, the thickness of the liquid crystal layer, and the number of retardation films used, the angle is appropriately selected and used.

As the retardation film 9, those manufactured by a known technique can be preferably used. In particular,
A stretched polymer film can be used.
Examples of the polymer film include polyarylate, polysulfone, polyether sulfone, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyvinyl alcohol, polyimide, cellulose and derivatives thereof. Among these, polyarylate, polysulfone, polyether sulfone and polycarbonate are preferable from the viewpoint of various properties as a retardation film. Also, an oriented film of a liquid crystalline polymer material can be used.
On the other hand, a retardation film in which the refractive index in the thickness direction of the film, which is used for the purpose of widening the viewing angle of the liquid crystal display device, is used can also be used. Further, as will be described later, when the polarization retardation composite film is used as it is as a substrate of a liquid crystal cell, the transparent electrode 4 and the orientation control film 5 may be previously formed on the retardation film.

A film having another function may be further laminated on the obtained polarization retardation composite film. Examples of such a film include a protective layer of a polarizing thin film, an antireflection film, and an antiglare film. However, the total thickness of components other than the retardation film is preferably 100 μm or less, and 70
It is particularly preferable that the thickness is μm or less. In the present invention, since the thickness of the polarizing thin film is 5 μm or less, the thickness of the polarization retardation composite film can be extremely easily set within the above range.

A liquid crystal cell can be constructed using the obtained polarization retardation composite film. The simplest way is
This is a method in which a polarization retardation composite film is attached to the outside of the substrate 3 of the liquid crystal cell as shown in FIG. In this case, the surface of the polarization retardation composite film having no polarization book film is attached to the liquid crystal cell substrate 3. At this time, the liquid crystal layer 7 is sandwiched by 2
A polarization retardation composite film may be attached to only one of the liquid crystal cell substrates 3 and a known polarizing element may be used on one of the liquid crystal cell substrates 3, or the polarization retardation composite film may be applied to both of the two liquid crystal cell substrates. It may be attached, but it is preferable to attach the polarization retardation composite film to both of the two liquid crystal cell substrates from the viewpoint of the viewing angle characteristics of the liquid crystal display device.

A polarization phase difference composite film may be attached to the liquid crystal cell substrate 3 on the liquid crystal layer 7 side for use. In this case, the transparent electrode 4 may be formed on the substrate in advance, and the polarization retardation composite film may be attached thereto, or the polarization retardation composite film may be attached to the substrate without the electrode 4 before the electrode 4 is attached. You may form. However, since the electric field can be efficiently applied to the liquid crystal layer 7, the polarization retardation composite film is attached to the substrate without the electrode 4 before the electrode 4 is attached.
Is preferably formed. In this case, the liquid crystal orientation control film 5 is provided after the transparent electrode 4 is formed. When the transparent electrode 4 is formed on the substrate in advance and the polarization retardation composite film is attached thereto, the liquid crystal alignment control film 5 is installed on the polarization retardation composite film. Has the property of controlling the orientation of liquid crystals on the surface of the retardation film 9, and this may be omitted.

As shown in FIG. 4, the polarization retardation composite film can be used as it is as a liquid crystal cell substrate. In this case, the electrode 4 and the liquid crystal alignment control film 5 are sequentially formed on the surface of the polarization retardation composite film (1 and 8 and 9) on which the polarization book film 1 is not provided. The obtained liquid crystal cell substrate holds the liquid crystal with the surface having the liquid crystal orientation control film 5 facing the liquid crystal layer side. At this time,
The polarization retardation composite film may be used for both of the two liquid crystal cell substrates, or one of them may be a known liquid crystal cell substrate, but both of the two liquid crystal cell substrates may be used as the polarization retardation composite film. This is preferable from the viewpoint of viewing angle characteristics of the liquid crystal display device. Further, when one known liquid crystal cell substrate is used, it is preferable to use a resin film, which is very similar to the polarization retardation composite film, as a base material in terms of the thickness of the liquid crystal display device.

[0040]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. The dichroic ratio in the present invention means the absorbance of polarized light in a direction parallel to the alignment direction of the dye in the polarizing thin film (A1) at a specific wavelength.
And the absorbance (A2) of the polarized light in the direction orthogonal to the orientation direction of the dye in the polarizing thin film were measured and calculated by the following formula. In particular, the value at the absorption peak wavelength was used.

## EQU1 ## Dichroic ratio = A1 / A2 As the absorbance value, the film alone was used after the absorption by the substrate was subtracted. Further, at the time of measuring the polarization retardation composite film, the absorption was measured by a method in which linearly polarized light was incident from the side having the polarizing thin film and light emitted from the back side was measured.

Example 1 <Formation of Alignment Film> A PTFE alignment film was obtained by using the method described in US Pat. No. 5,180,470.
Specifically, a glass substrate (2.5
(cm × 8.0 cm), a curved surface which is a side surface of a similarly heated PTFE cylinder having a length of 2 cm and a diameter of 1.0 cm is pressed, and the substrate is moved at a speed of 0.1 cm / sec to have a width of 2.0 cm. X A PTFE alignment film having a length of 7.0 cm was obtained. At this time, the cylinder was pressed against the substrate with a pressure of 5 kgf. The contact area with the substrate was observed to be about 0.4 cm ² . <Formation of Polarizing Thin Film> Table 1 was formed on the obtained PTFE alignment film.
The described D10 (manufactured by Nippon Senshoku Co., Ltd., trade name G205) was deposited. The degree of vacuum during vapor deposition was 10 ⁻⁵ Torr or less, and the thickness of the obtained polarizing thin film was about 100 nm. <Transition of polarizing thin film> Glass plate with transparent electrode (thickness 1.1
mm) on the surface having no transparent electrode was coated with a photo-curable resin (trade name 60 manufactured by Norland Co., Ltd.) by spin coating. This substrate was pressure-bonded so that the glass substrate having the polarizing thin film, the photocurable resin film, and the polarizing thin film were in contact with each other.
Next, ultraviolet rays were irradiated from the back side of the glass substrate on the photocurable resin film side to cure the photocurable resin. The polarizing thin film was transferred to the surface of the photocurable resin film by the operation of peeling off the two substrates. By the same operation, another glass substrate with a transparent electrode having the same polarizing thin film and photocurable resin film was prepared. <Measurement of dichroic ratio of polarizing thin film> 40 of the obtained polarizing thin film
When the polarized light absorbance in the range of 0 nm to 800 nm was measured, there was an absorption peak at about 510 nm. The dichroic ratio at the absorption peak was 10 or more. <Observation of Liquid Crystal Cell> Further, an alignment control film of polyimide is provided on the transparent electrode side of the glass substrate having the obtained two polarizing thin films and the transparent electrode, and a TN type liquid crystal cell is prepared with this as the liquid crystal layer side. When driving this TN type liquid crystal cell,
Shows good contrast. The thickness of the liquid crystal cell is about 2.2.
mm.

Example 2 <Formation of Alignment Film> The same operation as in Example 1 was performed to obtain a PTFE alignment film. <Formation of Polarizing Thin Film> Table 1 was formed on the obtained PTFE alignment film.
The described D6 (manufactured by Nippon Senshoku Co., Ltd., trade name G232) was deposited. The degree of vacuum during vapor deposition was 10 ⁻⁵ Torr or less, and the thickness of the obtained polarizing thin film was about 100 nm. <Transfer of Polarizing Thin Film> The same operation as in Example 1 was performed to transfer the polarizing thin film onto the surface of the glass plate with the transparent electrode without the transparent electrode. <Measurement of dichroic ratio of polarizing thin film> 40 of the obtained polarizing thin film
When the polarized light absorbance in the range of 0 nm to 800 nm was measured, there was an absorption peak at about 450 nm. The dichroic ratio at the absorption peak was 5 or more. <Observation of Liquid Crystal Cell> Further, an alignment control film of polyimide is provided on the transparent electrode side of the glass substrate having the obtained two polarizing thin films and a transparent electrode, and a TN type liquid crystal cell is prepared with this as the liquid crystal layer side. When this TN type liquid crystal cell is driven, good contrast is exhibited. The thickness of the liquid crystal cell is about 2.2 mm.

Example 3 <Formation of Alignment Film> The same operation as in Example 1 was performed to obtain a PTFE alignment film. <Formation of Polarizing Thin Film> The same operation as in Example 1 was performed to obtain a polarizing thin film. <Transition of polarizing thin film> Glass plate with transparent electrode (thickness 1.1
(mm) transparent electrode surface was coated with a photocurable resin (trade name 60 manufactured by Norland Co., Ltd.) by spin coating. This substrate was pressure-bonded so that the glass substrate having the polarizing thin film, the photocurable resin film, and the polarizing thin film were in contact with each other. Next, ultraviolet rays were irradiated from the back side of the glass substrate on the photocurable resin film side to cure the photocurable resin. The polarizing thin film was transferred to the surface of the photocurable resin film by the operation of peeling off the two substrates. By the same operation, another glass substrate with a transparent electrode having the same polarizing thin film and photocurable resin film was prepared. <Measurement of dichroic ratio of polarizing thin film> 40 of the obtained polarizing thin film
When the polarized light absorbance in the range of 0 nm to 800 nm was measured, there was an absorption peak at about 510 nm. The dichroic ratio at the absorption peak was 10 or more. <Observation of liquid crystal cell> Further, a thin film of a PTFE oligomer was vapor-deposited as a liquid crystal orientation control film on the transparent electrode side of the glass substrate having the obtained two polarizing thin films and a transparent electrode, and the TN type liquid crystal was used as the liquid crystal layer side. Make a cell. This T
Driving an N-type liquid crystal cell shows good contrast. The thickness of the liquid crystal cell is about 2.2 mm.

Example 4 <Formation of Alignment Film> The same operation as in Example 1 was performed to obtain a PTFE alignment film. <Formation of Polarizing Thin Film> On the obtained PTFE alignment film, a diacetylene derivative [1,6-di (N-carbazolyl) -2,
4-hexadiyne] was deposited. The degree of vacuum during vapor deposition is
It was 10 ^-5 Torr or less. The thickness of the obtained diacetylene film was about 50 nm. This was irradiated with ultraviolet rays from a mercury lamp to polymerize diacetylene to obtain a polydiacetylene film. <Transition of Polarizing Thin Film> The same operation as in Example 3 was performed to transfer the polarizing thin film onto the transparent electrode surface of the glass plate with a transparent electrode. <Measurement of dichroic ratio of polarizing thin film> 40 of the obtained polarizing thin film
When the polarized light absorbance in the range of 0 nm to 800 nm was measured, there was an absorption peak at about 620 nm. The dichroic ratio at the absorption peak was 4 or more. <Observation of Liquid Crystal Cell> Further, a TN type liquid crystal cell is prepared with the polarizing plate film side of the glass substrate having the obtained two polarizing thin films and the transparent electrode as the liquid crystal layer side. When this TN type liquid crystal cell is driven, good contrast is exhibited. The thickness of the liquid crystal cell is about 2.2 mm.

Example 5 <Formation of Alignment Film> By the same operation as in Example 1, a PTFE alignment film was obtained on a glass substrate. <Formation of Polarizing Thin Film> The same operation as in Example 1 was performed to obtain a polarizing thin film. <Formation of polarization retardation composite film> Polycarbonate retardation film having a thickness of 60 μm (Sumitomo Chemical Co., Ltd.)
A photocurable resin (product name 60 manufactured by Norland Co., Ltd.) was applied onto the surface of the product, product name Sumilite SEF-460428. The resin-coated surface was pressure-bonded to the glass substrate having the polarizing thin film. Next, ultraviolet rays were irradiated from the back side of the retardation film on the photocurable resin film side to cure the photocurable resin. The polarizing thin film was transferred to the surface of the photocurable resin film on the film by an operation of peeling off the retardation film from the glass substrate. At this time, the stretching axis of the retardation film and the polarization axis of the polarization book film were at an angle of 45 degrees. By the same operation, another polarization retardation composite film having the same polarizing thin film and photocurable resin film was produced. The thickness of this polarization retardation composite film was 65 μm. <Measurement of dichroic ratio of polarization retardation composite film> When the polarization absorbance of the polarization retardation composite film in the range of 400 nm to 800 nm is measured, there is an absorption peak at about 510 nm. The dichroic ratio at the absorption peak was 40 or more. <Observation of liquid crystal cell> Further, the obtained polarization retardation composite film is arranged on both sides of the STN type liquid crystal cell with the surfaces without the polarization book film facing the liquid crystal side and twisting the polarization axis by 240 °.
Driving a TN liquid crystal cell shows good contrast. The thickness of the liquid crystal cell is about 2.3 mm.

Example 6 <Formation of Alignment Film> By the same operation as in Example 1, a PTFE alignment film was obtained on a glass substrate. <Formation of Polarizing Thin Film> The same operation as in Example 1 was performed to obtain a polarizing thin film. <Formation of Polarization Retardation Composite Film> A polarization retardation composite film is obtained by the same operation as in Example 5. The thickness of this polarization retardation composite film is 65 μm. ITO was vapor-deposited on the surface of the polarization retardation composite film having no polarization book film to form a transparent electrode, and a polyimide film was applied on the transparent electrode, followed by rubbing parallel to the polarization axis of the polarization book film. <Observation of liquid crystal cell> Further, a liquid crystal is sandwiched between two polarization retardation composite films and twisted by 240 ° on both sides of the STN type liquid crystal layer, and when this STN type liquid crystal cell is driven, good contrast is obtained. Show. The thickness of the liquid crystal cell is about 0.2 mm
Is.

Example 7 <Formation of Alignment Film> By the same operation as in Example 1, a PTFE alignment film was obtained on a glass substrate. <Formation of Polarizing Thin Film> The same operation as in Example 1 was performed to obtain a polarizing thin film. <Transfer of Polarizing Thin Film> The same operation as in Example 1 is performed to transfer the polarizing thin film onto the surface of the glass plate with a transparent electrode (thickness 0.9 mm) having no transparent electrode. <Measurement of dichroic ratio of polarizing thin film> The same operation as in Example 1 was carried out to measure the polarization absorbance of the obtained polarizing thin film.
There is an absorption peak at 10 nm. The dichroic ratio at the absorption peak is 10 or more. <Observation of Liquid Crystal Cell> A TN type liquid crystal cell is prepared in the same manner as in Example 1. When this TN type liquid crystal cell is driven, good contrast is exhibited. The thickness of the liquid crystal cell is about 1.8 mm.

Comparative Example 1 Polarization retardation composite film (Sumitomo Chemical Co., Ltd., trade name Sumikalite SEF-460428 type and Sumikaran S)
When the thickness of H-1832 type bonded product) is measured, it is about 0.2.
It was 5 mm. Further, when an STN type liquid crystal cell similar to that in Example 5 is driven by using this polarization retardation composite film, good contrast is exhibited, but the thickness of the liquid crystal cell is about 2.8 mm.

Comparative Example 2 Using the polarization retardation composite film used in Comparative Example 1,
When a TN type liquid crystal cell similar to that in Example 7 is driven, good contrast is exhibited, but the thickness of the liquid crystal cell is about 2.4 mm.
Is.

[0050]

The liquid crystal display device of the present invention is thin, has a small number of laminations in the assembly process, and is easy to manufacture. INDUSTRIAL APPLICABILITY The liquid crystal display device and the polarization retardation composite film of the present invention are thin, have a simple structure and can be easily manufactured, and have great industrial value, especially in the field of card-type small information devices.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a liquid crystal display device according to a first embodiment or a second embodiment.

FIG. 2 is a schematic cross-sectional view of a liquid crystal display device shown in Example 4.

FIG. 3 is a schematic sectional view of a liquid crystal display device shown in Example 5.

FIG. 4 is a schematic cross-sectional view of a liquid crystal display device shown in Example 6.

[Explanation of symbols]

 1 ... Polarizing thin film 2 ... Fluorine-based resin alignment film 3 ... Liquid crystal cell substrate 4 ... Electrode 5 ... Liquid crystal alignment control film 6 ... Spacer 7 ... Liquid crystal layer 8 ... Adhesive layer 9 ... Retardation film

Claims (11)

[Claims] 1. A liquid crystal layer sandwiched between substrates having electrodes,
A liquid crystal display device having a polarizing thin film, wherein a polarizing thin film having a film thickness of 1 nm or more and 5 μm or less is bonded onto the substrate via an adhesive layer. 2. The liquid crystal layer has a positive dielectric anisotropy, and when a voltage is not applied, the long axis of the liquid crystal molecule is substantially parallel to the substrate,
A liquid crystal layer having a structure in which the major axis of the liquid crystal molecule is twisted about 90 ° or more and 270 ° or less about a spiral axis substantially perpendicular to the substrate. 1. The liquid crystal display device according to 1. 3. A polarizing thin film having a film thickness of 1 nm or more and 5 μm or less,
The liquid crystal display device according to claim 1, wherein the substrate having electrodes is bonded to the liquid crystal layer side. 4. A polarizing thin film having a film thickness of 1 nm or more and 5 μm or less,
The liquid crystal display device according to claim 3, which has a function of aligning the liquid crystal of the liquid crystal layer. 5. A polarizing thin film having a film thickness of 1 nm or more and 5 μm or less,
A polarization retardation composite film, characterized by being laminated on one surface of a retardation film. 6. A liquid crystal molecule having a positive dielectric anisotropy sandwiched between substrates having electrodes, the major axis of the liquid crystal molecule being substantially parallel to the substrate when no voltage is applied, and the major axis of the liquid crystal molecule being A liquid crystal display device having a polarizing thin film and a liquid crystal layer configured to have a twisted structure in the range of 90 ° or more to 270 ° or less around a spiral axis substantially perpendicular to the substrate, and at least one of the substrates. 6. A liquid crystal display device, characterized in that the polarization retardation composite film according to claim 5 is arranged inside or outside of said liquid crystal layer with the surface having no polarizing thin film facing the liquid crystal layer side. 7. A liquid crystal molecule having a positive dielectric anisotropy sandwiched between substrates having electrodes, the major axis of the liquid crystal molecule being substantially parallel to the substrate when no voltage is applied, and the major axis of the liquid crystal molecule being A liquid crystal display device having a polarizing thin film and a liquid crystal layer configured to have a twisted structure between about 90 ° and about 270 ° about a spiral axis substantially perpendicular to the substrate, and a liquid crystal display device having a polarizing thin film on both outer sides thereof. Item 6. A liquid crystal display device, comprising the polarization retardation composite film according to item 5 arranged with the surface without the polarization thin film facing the liquid crystal layer side. 8. A liquid crystal molecule having a positive dielectric anisotropy, the major axis of the liquid crystal molecule being substantially parallel to the substrate when no voltage is applied, and the major axis of the liquid crystal molecule being around a spiral axis substantially perpendicular to the substrate. Almost 9
In a liquid crystal display device having a liquid crystal layer configured to have a twisted structure between 0 ° and 270 ° and a polarizing thin film, at least one of substrates having electrodes sandwiching the liquid crystal layer is claimed. 6. The liquid crystal display device according to item 5, wherein the polarization phase difference composite film is arranged with the surface without the polarization thin film facing the liquid crystal layer side. 9. A polarizing thin film is formed on a base material having a fluorine-based resin alignment film on its surface, and then the polarizing thin film is transferred onto the base material in a liquid crystal display device.
Or the method for manufacturing a liquid crystal display device according to item 8. 10. The polarization retardation composite film according to claim 5, wherein the polarization thin film is transferred onto the retardation film after the polarization thin film is formed on the substrate having the fluorine-based resin alignment film on the surface thereof. Manufacturing method. 11. A liquid crystal display device having a liquid crystal layer sandwiched between substrates having electrodes, a polarizing thin film, and a fluororesin alignment film, wherein a polarizing thin film having a thickness of 1 nm or more and 5 μm or less has an adhesive layer on the substrate. A liquid crystal display device, wherein the liquid crystal display device is characterized in that it is bonded via the polarizing thin film, and a fluorine-based resin alignment film is bonded onto the polarizing thin film, and the fluorine-based resin alignment film has a function of aligning the liquid crystal of the liquid crystal layer.