JP2012155258A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device of a lateral electric field type with a shield function for electrostatic influences from the outside and inside of the device and external electromagnetic hindrances.SOLUTION: The liquid crystal display device according to the present invention includes: a liquid crystal layer, a first transparent substrate and a second transparent substrate disposed facing each other via the liquid crystal layer; a transparent conductive film disposed in the other side of the liquid crystal layer of the first transparent substrate; and a display electrode and a reference electrode disposed in the side of the liquid crystal layer of the second transparent substrate. The transparent conductive film is formed by coating on a principal surface in the other side of the liquid crystal layer of the first transparent substrate, and the transparent conductive film has a specific characteristic.

Description

  The present invention relates to a liquid crystal display device, and more particularly to a horizontal electric field type liquid crystal display device.

  The liquid crystal display device utilizes the characteristics such as light weight, thinness, and low power consumption, and in recent years, the market has expanded as a small display device such as various information equipment terminals and cameras, and also as a large display device such as a television. As a type of liquid crystal display device, a vertical electric field method represented by a TN (twisted nematic) type has been dominant, but recently, a liquid crystal display device called a horizontal electric field method has become mainstream. Yes.

  In a vertical electric field type liquid crystal display device, among transparent substrates disposed to face each other with a liquid crystal layer interposed therebetween, one transparent substrate is provided with a pixel electrode, and the other transparent substrate is provided with a common electrode. The liquid crystal orientation is controlled by an electric field generated between the pixel electrode and the common electrode, that is, an electric field perpendicular to the transparent substrate. On the other hand, the configuration of the horizontal electric field type liquid crystal display device includes a display electrode and a reference electrode mainly disposed on the liquid crystal layer side of one transparent substrate among the transparent substrates arranged to face each other via the liquid crystal layer. So that the light transmitted through the liquid crystal layer is modulated by controlling the orientation of the liquid crystal by an electric field generated between the display electrode and the reference electrode, that is, an electric field generated in parallel with the transparent substrate. It is a thing.

  The horizontal electric field type liquid crystal display device has the advantage of a wider viewing angle than the vertical electric field method, but as a problem that does not occur in the vertical electric field type liquid crystal display device, electrostatic influence from the outside or inside of the device In addition, there is a problem that the display quality is deteriorated such that light is lost when black is displayed due to external electromagnetic interference. This is because a horizontal electric field type liquid crystal display device has a structure in which a display electrode and a reference electrode are integrated on one transparent substrate, and therefore has a conductive layer having a shielding function against external static electricity. This is because it is not configured.

  In order to solve such problems, a conductive layer having translucency is formed on the surface opposite to the liquid crystal layer of the transparent substrate far from the backlight unit among the transparent substrates of the liquid crystal display device, Techniques for providing a shielding function have been proposed. Specifically, conductive particles are scattered in a method of forming a sputtering film made of ITO as a conductive layer, or in an adhesive material attached to a transparent substrate of a liquid crystal display device. A method for forming a conductive layer has been proposed (see Patent Document 1).

Japanese Patent No. 2758864

  However, the method of forming a conductive layer by sputtering described in Patent Document 1 requires a large vacuum device for the sputtering process, and cannot simplify the manufacturing process, which is disadvantageous in terms of manufacturing cost. is there. Further, in the method of forming a conductive layer by dispersing conductive particles in the adhesive material described in Patent Document 1, the adhesive layer is generally thick with a thickness of 10 μm or more. There is a problem that transparency is lowered in the method of imparting conductivity to the layer.

  The present invention solves the above-mentioned problems, and the volume content and average particle diameter of the conductive inorganic particles and the film thickness of the transparent conductive film satisfy specific requirements so that the antistatic function is high and the transparency is high. A transparent conductive film excellent in the above is disposed in a horizontal electric field type liquid crystal display device.

In the liquid crystal display device of the present invention, the liquid crystal layer, the first transparent substrate and the second transparent substrate disposed to face each other with the liquid crystal layer interposed therebetween, and the liquid crystal layer of the first transparent substrate are: A liquid crystal display device comprising: a transparent conductive film disposed on the opposite side; and a display electrode and a reference electrode disposed on the liquid crystal layer side of the second transparent substrate, wherein the transparent conductive film comprises: The first transparent substrate is formed on the main surface opposite to the liquid crystal layer by coating, and the transparent conductive film includes conductive inorganic particles and a resin component, and the volume content A of the conductive inorganic particles is A. Is 25 to 60%, the average particle diameter B of the conductive inorganic particles is 30 to 200 nm, the film thickness C of the transparent conductive film is 0.2 to 5.0 μm, and the conductive Volume content A of inorganic particles, average particle diameter B of the conductive inorganic particles, and the transparent conductive material Relationship thickness C of, characterized by satisfying the following requirements Equation (1).
Formula (1) 0.8 ≦ (A / 100) ² × √B × C ≦ 4.0

  According to the present invention, a transparent conductive film having a high antistatic function and excellent transparency can be directly and easily disposed on a transparent substrate of a horizontal electric field type liquid crystal display device.

FIG. 1 is a schematic cross-sectional view showing an example of the liquid crystal display device of the present invention.

  The liquid crystal display device of the present invention includes a liquid crystal layer, a first transparent substrate and a second transparent substrate that are disposed to face each other with the liquid crystal layer interposed therebetween, and the liquid crystal layer of the first transparent substrate. A transparent conductive film disposed on the opposite side; and a display electrode and a reference electrode disposed on the liquid crystal layer side of the second transparent substrate. In addition, the transparent conductive film is formed by coating on a main surface of the first transparent substrate opposite to the liquid crystal layer, and the transparent conductive film includes conductive inorganic particles and a resin component, The volume content A of the conductive inorganic particles is 25 to 60%, the average particle diameter B of the conductive inorganic particles is 30 to 200 nm, and the film thickness C of the transparent conductive film is 0.2 to 5.0 μm, and the relationship between the volume content A of the conductive inorganic particles, the average particle diameter B of the conductive inorganic particles, and the film thickness C of the transparent conductive film satisfies the requirement of the following formula (1). It is characterized by.

Formula (1) 0.8 ≦ (A / 100) ² × √B × C ≦ 4.0

  The liquid crystal display device of the present invention includes a liquid crystal layer, a first transparent substrate and a second transparent substrate that are disposed to face each other with the liquid crystal layer interposed therebetween, and the liquid crystal layer of the first transparent substrate. Since a transparent conductive film disposed on the opposite side and a display electrode and a reference electrode disposed on the liquid crystal layer side of the second transparent substrate are provided, the horizontal electric field type liquid crystal display device includes Shielding function against electrostatic influences from outside or inside and electromagnetic interference from outside can be provided.

  In the liquid crystal display device of the present invention, the transparent conductive film is formed by coating on the main surface of the first transparent substrate opposite to the liquid crystal layer, and the transparent conductive film is conductive. Including the inorganic particles and the resin component, the volume content A of the conductive inorganic particles is 25 to 60%, the average particle diameter B of the conductive inorganic particles is 30 to 200 nm, and the transparent conductive film Of the conductive inorganic particles, the average particle diameter B of the conductive inorganic particles, and the film thickness C of the transparent conductive film, In order to satisfy the requirement of the above formula (1), a transparent conductive film having a high antistatic function and excellent transparency can be directly and easily disposed on a transparent substrate of a horizontal electric field type liquid crystal display device.

In the present invention, as a result of earnestly examining the correlation between the film thickness of the transparent conductive film, the volume content of the conductive inorganic particles in the transparent conductive film, and the average particle diameter, the volume content A and the average particle diameter of the conductive inorganic particles B and the film thickness C of the transparent conductive film satisfy the requirement of 0.8 ≦ (A / 100) ² × √B × C ≦ 4.0, so that the balance between conductivity and transparency can be achieved. A transparent conductive film could be obtained.

  When the volume content of the conductive inorganic particles in the transparent conductive film is a volume content A, the volume content A is 25 to 60%, preferably 30 to 50%, and preferably 35 to 45%. It is particularly preferred. Here, the volume content A means the ratio of the volume of the conductive inorganic particles in the transparent conductive film made of a nonvolatile solid component. When the volume content A exceeds 60%, not only the scattering by the particles in the transparent conductive film increases, but also the interface between the particles and the air increases without filling the resin between the conductive inorganic particles, Since particles are exposed on the surface of the conductive film and the surface becomes rough, there arises a problem that the haze of the coating film increases. On the other hand, when the volume content A is less than 25%, the number of contact points between particles becomes too small, and the surface resistance of the transparent conductive film increases.

  When the average particle diameter of the conductive inorganic particles in the transparent conductive film is defined as the average particle diameter B, the average particle diameter B is 30 to 200 nm, preferably 50 to 180 nm, and preferably 80 to 150 nm. Particularly preferred. Here, the average particle diameter B refers to the average dispersed particle diameter of the conductive inorganic particles contained in the transparent conductive film, and the unit is expressed in nanometers (nm). The average particle size is obtained by observing and measuring the particle size of each particle on the surface or cross section of the transparent conductive film with a transmission electron microscope (TEM) and then averaging the particle size of at least 100 particles. Is obtained. When the average particle diameter B exceeds 200 nm, there arises a problem that the haze value of the coating film increases excessively due to particle scattering. In order to reduce the average particle diameter B of the conductive inorganic particles, it is necessary to use conductive inorganic particles having a small primary particle diameter. In general, the smaller the primary particle diameter of the particles, the larger the specific surface area. Since dispersion increases and dispersion becomes difficult, it is substantially difficult to make the average particle diameter B less than 30 nm.

  In order to make the average particle diameter B 30 to 200 nm, the primary particle diameter of the conductive inorganic particles is preferably 5 to 180 nm. Here, the primary particle size of the particles is at least after measuring and measuring the particle size of each particle separated by a grain boundary with a transmission electron microscope (TEM) using the conductive inorganic particles themselves as a sample. An average particle size obtained by averaging the particle sizes of 100 particles. When the primary particle diameter of the conductive inorganic particles is less than 5 nm, it tends to be difficult to obtain particles with good crystallinity. On the other hand, if the primary particle diameter is larger than 180 nm, it is difficult to make the average particle diameter B 200 nm or less.

  When the film thickness of the transparent conductive film of the present invention is a film thickness C, the film thickness C is 0.2 to 5.0 μm, and preferably 0.5 to 3.0 μm. When the film thickness C is less than 0.2 μm, the light transmittance of the transparent conductive film is improved. However, since the transparent conductive film is too thin, the surface resistance increases and the shielding function decreases. Further, when the film thickness C is increased, the surface resistance tends to decrease, but when the film thickness C exceeds 5.0 μm, the light transmittance decreases.

  In the transparent conductive film, the volume content A (%), the average particle diameter B (nm), and the film thickness C (μm) satisfy the relationship of the following formula (1).

Formula (1) 0.8 ≦ (A / 100) ² × √B × C ≦ 4.0

  In the transparent conductive film, when the film thickness C increases, the amount of conductive inorganic particles per unit area of the sheet increases, and thus the surface resistance tends to decrease. On the other hand, light is absorbed and scattered by the particles. There arises a problem that the transmittance decreases and haze increases.

  Further, when the film thickness C is constant, if the average particle diameter B of the conductive inorganic particles is reduced, the particle scattering is reduced and the haze is reduced. However, since the particle indirect points between the conductive inorganic particles are increased and the contact resistance is increased, the volume content A is increased as compared with the case where the average particle diameter B is large in order to reduce the surface resistance of the transparent conductive film. There is a need.

  Further, when the volume content A is constant, increasing the average particle diameter B can reduce the surface resistance and improve the conductivity. However, since haze due to particle scattering increases, it is necessary to lower the volume content A in order to prevent white turbidity of the transparent conductive film.

  The numerical formula (1) is an index for improving the balance between transparency and conductivity in the transparent conductive film. In the present invention, transparency is indicated by light transmittance, and the lower the value of light transmittance, the better the transparency. Moreover, in this invention, electroconductivity is shown by surface resistance, and it is excellent in electroconductivity, so that the value of surface resistance is low.

  Specifically, when the value of the mathematical formula (1) is less than 0.8, the surface resistance of the transparent conductive film is increased and the antistatic function, that is, the conductivity is lowered. On the other hand, when the value of the above mathematical formula (1) exceeds 4.0, the light transmittance of the transparent conductive film decreases, the haze value increases, and the film becomes clouded.

The surface resistance of the transparent conductive film is preferably 1 × 10 ⁴ to 1 × 10 ¹⁴ Ω / square, and more preferably 1 × 10 ⁵ to 1 × 10 ¹² Ω / square. When the surface resistance exceeds 1 × 10 ¹⁴ Ω / square, the shielding function is lowered and it is difficult to prevent display deterioration of the liquid crystal display device. Further, when the amount of the conductive inorganic particles contained in the transparent conductive film is increased, the surface resistance is decreased, but light scattering by the conductive inorganic particles is also increased, haze is increased, and transparency is decreased. Therefore, it is difficult to make the surface resistance less than 1 × 10 ⁴ Ω / square while maintaining the transparency of the transparent conductive film.

  The light transmittance in the wavelength region of 450 to 650 nm of the transparent conductive film is preferably 70% or more, and more preferably 90% or more.

  Next, the manufacturing method of the said transparent conductive film is demonstrated.

  The method for producing the transparent conductive film includes a step of producing a coating composition containing conductive inorganic particles and a resin component, a step of forming a coating film by applying the coating composition on a transparent substrate, And drying the coating film to form a transparent conductive film.

  The coating composition used for forming the transparent conductive film contains conductive inorganic particles and a resin component.

  When the volume content of the conductive inorganic particles in the coating composition is defined as the volume content A1, the volume content A1 is 25 to 60%, preferably 30 to 50%, and preferably 35 to 45%. It is particularly preferred. Here, the volume content A1 means the ratio of the volume of the conductive inorganic particles to the entire nonvolatile solid component excluding the solvent. By setting the volume content A1 of the conductive inorganic particles in the coating composition to 25 to 60%, the volume content A of the conductive inorganic particles in the transparent conductive film formed by applying the coating composition is also 25 to 25%. 60% can be achieved.

  When the average particle diameter of the conductive inorganic particles in the coating composition is defined as the average particle diameter B1, the average particle diameter B1 is 30 to 200 nm, preferably 50 to 180 nm, and particularly preferably 80 to 150 nm. preferable. Here, the average particle diameter B1 refers to the average particle diameter of the conductive inorganic particles dispersed in the coating composition, and the unit is expressed in nanometers (nm). The average particle diameter is defined as an average value of particle size distribution measured by a laser diffraction scattering method or a dynamic light scattering method. By setting the average particle size B1 of the conductive inorganic particles in the coating composition to 30 to 200 nm, the average particle size B of the conductive inorganic particles in the transparent conductive film formed by applying the coating composition is also 30 to 200 nm. Can be.

  The volume content A1 (%), the average particle diameter B1 (nm), and the film thickness C (μm) of the transparent conductive film satisfy the relationship of the following mathematical formula (2).

Formula (2) 0.8 ≦ (A1 / 100) ² × √B1 × C ≦ 4.0

Conductive inorganic in the transparent conductive film formed by applying the coating composition by setting the volume content A1 of the conductive inorganic particles in the coating composition to 25 to 60% and the average particle diameter B1 to 30 to 200 nm. The volume content A of the particles can be 25 to 60%, and the average particle diameter B can be 30 to 200 nm. Further, when the volume content A1 (%), the average particle diameter B1 (nm), and the film thickness C (μm) of the transparent conductive film satisfy the requirements of the formula (2), the conductive inorganic particles in the transparent conductive film The volume content A, the average particle diameter B, and the film thickness C of the transparent conductive film are also the requirements of the above formula (1), that is, 0.8 ≦ (A / 100) ² × √B × C ≦ 4.0. It will satisfy the relationship.

  The conductive inorganic particles are not particularly limited as long as the particles have both transparency and conductivity. For example, metal particles, carbon particles, conductive metal oxide particles, conductive nitride particles, and the like are used. be able to. Among these, conductive metal oxide particles having both transparency and conductivity are preferable. Examples of the conductive metal oxide particles include tin oxide particles, antimony-containing tin oxide (ATO) particles, tin-containing indium oxide (ITO) particles, aluminum-containing zinc oxide (AZO) particles, and gallium-containing zinc oxide (GZO) particles. The metal oxide particles are mentioned. The conductive metal oxide particles may be used alone or in combination of two or more. The conductive inorganic particles preferably contain at least one selected from the group consisting of tin oxide particles, antimony-containing tin oxide particles and tin-containing indium oxide particles as a main component. This is because these compounds are excellent in transparency, conductivity, and chemical properties, and can achieve high light transmittance and conductivity even when formed into a coating film. Here, a main component means the electroconductive inorganic particle contained 70weight% or more with respect to the whole electroconductive inorganic particle.

  The resin component is not particularly limited as long as it can form a coating film by dispersing the conductive inorganic particles. For example, an acrylic resin, a polyester resin, a polyamide resin, a polycarbonate resin, a polyurethane resin, a polystyrene resin, a polyvinyl chloride resin, a polyvinylidene chloride resin, a polyvinyl alcohol resin, a polyvinyl acetate resin, and a photocurable monomer and a polymerization initiator. Examples thereof include a photocurable resin.

  The coating composition preferably further contains a solvent. Since the coating composition contains many conductive inorganic particles that are solid components, even if the resin component is a liquid component such as a photocurable monomer, the coating composition is suitable for application if it does not contain a solvent. It tends to be difficult to obtain a high viscosity.

  The solvent is not particularly limited as long as it dissolves the resin component and can be removed by a drying step after coating. For example, alcohols such as ethanol, propanol and butanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone and cyclohexanone; ethers such as diethyl ether, tetrahydrofuran and dioxane; aromatic compounds such as benzene, toluene and xylene Glycols such as ethylene glycol, diethylene glycol and propylene glycol; glycol alkyl ethers and glycol alkyl esters such as ethylene glycol monomethyl ether and propylene glycol monomethyl ether acetate;

  The coating composition may further contain a dispersant for improving the dispersibility of the conductive inorganic particles and a surface conditioner for improving the wettability and / or leveling properties of the transparent substrate. .

  The preparation of the coating composition is not particularly limited as long as the conductive inorganic particles can be dispersed in the resin and / or solvent. For example, in order to disperse conductive inorganic particles, mechanical treatment with media such as ball mill, sand mill, pico mill, paint conditioner, or dispersion treatment using an ultrasonic disperser, homogenizer, disper, jet mill, etc. May be applied.

  Next, the coating composition is applied to a transparent substrate to form a transparent conductive film. The coating method is not particularly limited as long as it is a coating method capable of forming a smooth coating film. For example, spin coating, roll coating, die coating, air knife coating, blade coating, reverse coating, gravure coating, micro gravure coating, or other coating methods, gravure printing, screen printing, offset printing, inkjet printing, and other printing methods, spray coating, A coating method such as dip coating can be used. After applying the coating composition, the solvent is removed by drying. If necessary, the transparent conductive film may be formed by irradiating the coating film with UV light or EB light to cure the coating film. Moreover, as a transparent substrate which forms a transparent conductive film, what is necessary is just a transparent and smooth board | substrate, and it is especially preferable that it is a glass substrate.

  The liquid crystal display device of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of the liquid crystal display device of the present invention.

  In FIG. 1, a liquid crystal display device 10 of the present invention includes a liquid crystal layer 11, a first transparent substrate 12a and a second transparent substrate 12b arranged to face each other with the liquid crystal layer 11 therebetween, and a first transparent substrate. The transparent conductive film 13 arrange | positioned on the opposite side to the liquid crystal layer 11 of the board | substrate 12a is provided. Although not shown, a display electrode and a reference electrode are disposed on the liquid crystal layer 11 side of the second transparent substrate 12b. Thus, the liquid crystal display device 10 constitutes a horizontal electric field type liquid crystal display device.

  The transparent conductive film 13 is formed by coating on the main surface of the first transparent substrate 12a opposite to the liquid crystal layer 11.

  Further, a polarizing plate 14a is disposed on the transparent conductive film 13, and a polarizing plate 14b is disposed outside the second transparent substrate 12b. A backlight unit 15 is disposed outside the polarizing plate 14b. Further, the liquid crystal layer 11 is sealed by a sealing portion 16.

  The liquid crystal display device 10 of the present invention includes a liquid crystal layer 11, a first transparent substrate 12a and a second transparent substrate 12b that are arranged to face each other with the liquid crystal layer 11 interposed therebetween, and a liquid crystal of the first transparent substrate 12a. Since the transparent conductive film 13 disposed on the side opposite to the layer 11 and the display electrode and the reference electrode (not shown) disposed on the liquid crystal layer 11 side of the second transparent substrate 12b are provided. The horizontal electric field type liquid crystal display device can be provided with a shield function against electrostatic influences from outside or inside the device and external electromagnetic interference.

  Hereinafter, the present invention will be described in detail based on examples. However, the present invention is not limited to the following examples.

  First, an ITO dispersion composition was prepared as follows.

<ITO dispersion composition>
The following components were weighed out in a 100 ml plastic bottle and dispersed with a paint shaker (manufactured by Toyo Seiki Co., Ltd.) for 20 minutes, and then the zirconia beads were removed to obtain an ITO dispersion composition. The tin content in the following tin-containing indium oxide (ITO) particles is 10% by weight.

(1) Tin-containing indium oxide (ITO) particles 12.0 g
(2) Dispersant “BYK111” (trade name, manufactured by Big Chemie) 0.60 g
(3) Methyl ethyl ketone (Wako Pure Chemical Industries, Ltd.) 13.7g
(4) Toluene (Wako Pure Chemical Industries, Ltd.) 13.7g
(5) Zirconia beads (for stirring and dispersing liquid, diameter 0.3 mm) 60.0 g

  The average particle diameter of the ITO particles in the ITO dispersion composition was measured with a dynamic light scattering particle size distribution meter (trade name “N4PLUS” manufactured by Coulter, Inc.), and it was 180 nm. As described above, the primary particle diameter of the raw material ITO particles was measured with a transmission electron microscope (TEM) and found to be 32 nm. The primary particle size of the ITO particles is the result of measuring and averaging the particle size of 100 particles.

  Next, a coating composition was prepared as follows.

<Coating composition>
The ITO dispersion composition and the following components were weighed and stirred into a plastic bottle shielded from ultraviolet rays to prepare 30 g of a coating composition.

(1) ITO dispersion composition 18.0 g
(2) Acrylic resin “BR106” (trade name, manufactured by Mitsubishi Rayon Co., Ltd.) 1.83 g
(3) Methyl ethyl ketone (Wako Pure Chemical Industries, Ltd.) 2.27g
(4) Toluene (Wako Pure Chemical Industries, Ltd.) 2.27g
(5) Cyclohexanone (Wako Pure Chemical Industries, Ltd.) 5.53 g

  When the weight content is M, the specific gravity of ITO is 7.1, and the specific gravity of the acrylic resin is 1.1, the volume content can be calculated by the following mathematical formula (3).

  Formula (3) Volume content = M / 7.1 / [M / 7.1 + (1-M)] / 1.1

  As a result of the calculation, the weight content of ITO particles in the non-volatile solid component of the coating composition was 72.0%, and the volume content of ITO particles was 28.5%.

  Next, after coating the coating composition on an optical glass substrate having a thickness of 1 mm using a spin coater ("1-HDX2" product name, manufactured by Mikasa) at a rotation speed of 500 rpm, It was dried for 2 minutes to obtain a transparent conductive film. As a result of observing and measuring the average particle diameter of the ITO particles in this transparent conductive film with a transmission electron microscope (TEM), it is 185 nm and is approximately the same as the average particle diameter of the ITO particles in the coating composition. I understood. In addition, the average particle diameter of said ITO particle | grains is a result of measuring and averaging the particle diameter of 100 particles.

  Subsequently, the film thickness, surface resistance, and light transmittance of the transparent conductive film were measured as follows.

<Film thickness>
The transparent conductive film was cut together with the glass substrate, and the film thickness was measured by observing a cross section with a scanning electron microscope (SEM, “S-4500”, trade name, manufactured by Hitachi, Ltd.). As a result, the film thickness was 1.1 μm.

<Surface resistance>
The surface resistance of the transparent conductive film was measured using a surface resistance meter (trade name “Rolesta AP-MCP-T400” manufactured by Dia Instruments). As a result, the surface resistance was 2.3 × 10 ⁶ Ω / square.

<Light transmittance>
First, a light transmittance spectrum in a wavelength region of 450 to 650 nm was measured using an ultraviolet-visible near-infrared spectrophotometer “V-570” (trade name, manufactured by JASCO Corporation). Next, the light transmittance of the glass substrate was measured, and the light transmittance spectrum of only the transparent conductive film obtained by subtracting the light transmittance of the glass substrate was averaged for the light transmittance in the wavelength region of 450 to 650 nm. It was set as the transmittance. As a result, the light transmittance of the transparent conductive film was 95.4%.

Example 1
A liquid crystal display device having the structure shown in FIG. 1 was produced using the coating composition. The transparent conductive film is coated at a rotational speed of 500 rpm on the main surface opposite to the liquid crystal layer of the upper glass substrate corresponding to the first transparent substrate using a spin coater, and then dried at 100 ° C. Formed by drying for 2 minutes on a machine. Next, a ground wire was attached to the end of the transparent conductive film with a silver paste (“Dotite D-362” trade name, manufactured by Fujikura Kasei Co., Ltd.), and then a polarizing plate was attached on the transparent conductive film. A polarizing plate was also attached to the backlight side of the lower glass substrate corresponding to the second transparent substrate provided with the display electrode and the reference electrode.

  Next, light is emitted from the lower glass substrate side by a backlight, and after confirming that the liquid crystal display device is in a black state in a non-energized state, the upper glass substrate is charged with a voltage ± 12 kV by an electrostatic application device Static electricity was applied. Thereafter, the ground wire of the transparent conductive film was grounded, and as a result of confirming the display of the non-energized state, the liquid crystal display device maintained a black display.

(Comparative Example 1)
A liquid crystal display device was produced in the same manner as in Example 1 except that the transparent conductive film was not disposed. Next, in the same manner as in Example 1, after irradiating light from the lower glass substrate side with a backlight and confirming that the liquid crystal display device is in a black state in a non-energized state, electrostatic application is applied to the upper glass substrate. Static electricity was applied at a voltage of ± 12 kV with the apparatus. Then, as a result of confirming the display in the non-energized state, the liquid crystal display device showed white floating due to light loss, and the black display could not be completely maintained.

  According to the present invention, a transparent conductive film having a high antistatic function and excellent transparency can be directly and easily disposed on a transparent substrate of a horizontal electric field type liquid crystal display device. The device can be provided with a shield function against electrostatic influences from outside or inside the device and external electromagnetic interference.

DESCRIPTION OF SYMBOLS 10 Liquid crystal display device 11 Liquid crystal layer 12a 1st transparent substrate 12b 2nd transparent substrate 13 Transparent electrically conductive film 14a, 14b Polarizing plate 15 Backlight unit 16 Sealing part

Claims (4)

A liquid crystal layer, a first transparent substrate and a second transparent substrate disposed to face each other with the liquid crystal layer interposed therebetween, and a transparent conductive layer disposed on the opposite side of the first transparent substrate from the liquid crystal layer A liquid crystal display device including a film and a display electrode and a reference electrode disposed on the liquid crystal layer side of the second transparent substrate,
The transparent conductive film is formed on the main surface of the first transparent substrate opposite to the liquid crystal layer by coating,
The transparent conductive film includes conductive inorganic particles and a resin component,
The volume content A of the conductive inorganic particles is 25 to 60%,
The average particle diameter B of the conductive inorganic particles is 30 to 200 nm,
The film thickness C of the transparent conductive film is 0.2 to 5.0 μm,
The relationship between the volume content A of the conductive inorganic particles, the average particle diameter B of the conductive inorganic particles, and the film thickness C of the transparent conductive film satisfies the requirement of the following formula (1). apparatus.
Formula (1) 0.8 ≦ (A / 100) ² × √B × C ≦ 4.0 The liquid crystal display device according to claim 1, wherein the transparent conductive film has a surface resistance of 1 × 10 ⁴ to 1 × 10 ¹⁴ Ω / square.   The liquid crystal display device according to claim 1, wherein the transparent conductive film has a light transmittance of 70% or more in a wavelength region of 450 to 650 nm.   The liquid crystal display device according to claim 1, wherein the conductive inorganic particles are at least one selected from the group consisting of tin oxide particles, antimony-containing tin oxide particles, and tin-containing indium oxide particles.

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