JPH06297629A - Ultrafine particle film, method of forming the same, transparent plate and image display device - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to an ultrafine particle film which is excellent in preventing stains from adhering and which is effective in preventing visible light reflection. Particularly, the ultrafine particle film applicable to a large area at a low cost and the application thereof An image display plate such as a cathode ray tube is formed by a simple method. [Structure] A Braun tube 21 is attached to a coating solution tank 22, and the coating solution tank 22 is first filled with a coating solution 23 containing antistatic SnO ₂ ultrafine particles, and then the surface of the Braun tube 21 is covered with the coating solution at a predetermined speed. Exposed to form a conductive film,
Next, the same operation is carried out by using a coating solution prepared by mixing ultrafine particles for preventing visible light reflection in another coating solution tank to form a visible light antireflection film on the coating solution, and then water repellent treatment is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrafine particle film and a method for forming the same, a transparent plate and an image display plate to which the film is applied, and a method for manufacturing the same, and more particularly to preventing reflection and electrification of the image display plate and An ultrafine particle film having water repellency on the surface,
The present invention relates to a transparent plate and an image display plate manufacturing method using the same.

[0002]

2. Description of the Related Art A film (antireflection film) for reducing the reflected light on the surface of a transparent plate has been studied for a long time and has been used for optical instruments such as cameras, microscopes and binoculars. Currently,
It is used as an antireflection filter for reducing the reflected light of the visual display terminal (VDT). Although various antireflection films have been considered, the ones currently used are mainly multilayer films and heterogeneous films.

The multilayer film has a structure in which at least three layers of a low refractive index substance and a high refractive index substance are alternately laminated on the surface of a transparent plate, and antireflection is achieved by a total effect of optical interference between the layers. There is. Regarding the multilayer film, Physics of Thin Film Volume 2 (1964), pages 242 to 28
Page 4 (Phyiscs of Thin Films
2, (1964) p. 242-p284).

In addition, the heterogeneous film having a refractive index distribution in the film thickness direction is generally a transparent plate whose surface is made porous.

After forming an island-shaped metal vapor deposition film on the glass surface,
A method of forming a non-uniform film by forming fine unevenness by sputter etching to reduce the reflectance is described in Applied Physics Letter No. 36 (1980), pages 727 to 730 (Apl. Phys. Le.
tt, 36 (1980) p.727-p730).

On the other hand, in the cathode ray tube, it is required to form a conductive film in order to prevent the electrification of the glass surface and to devise an antireflection method.

By the way, the reason why the front panel surface (image display plate) of a cathode ray tube such as a cathode ray tube is charged is as shown in FIG. 9, which is thin and uniform on the phosphor 93 usually coated on the inner surface 92 of the cathode ray tube 91. This is because the aluminum film 94 is vapor-deposited, and when a high voltage is applied to the aluminum film 94, a charging phenomenon is caused by electrostatic induction on the cathode ray tube front panel 95 when the high voltage is applied and cut off.

[0008] Preventing such electrification on the surface of the display tube,
Further, a method of preventing reflection on the surface is disclosed in Japanese Patent Laid-Open No. 61-51101. In this method, first, a conductive film is formed on a glass substrate by a physical vapor phase method such as a vacuum vapor deposition method or a sputtering method or a chemical vapor phase method, and an antireflection film is formed on the conductive film. .

On the other hand, a method of treating the glass surface with water repellency is disclosed in Japanese Patent Laid-Open No. 4-124047. In this method, first, a metal oxide film is formed on a glass substrate by a sol-gel method or the like, fine irregularities are formed on the surface thereof, and a water repellent treatment agent is further coated thereon. In these methods, first, it is necessary to bake at a high temperature of about 500 ° C. in order to form a strong metal oxide. For this reason, surface hydroxyl groups (O
H) decreases and the adhesion strength becomes weak. For this reason, minute irregularities have been formed on the surface to have an anchor effect and enhance the adhesion strength.

[0010]

The above-mentioned prior art method of forming an antireflection film is limited to the sputtering method and the vacuum deposition method and requires high-precision control of the film thickness, so that the cost is high and the area is large. There is a problem that it is difficult to apply to a substrate.

In this case, the antireflection film is basically formed by vapor-depositing several layers of substances having different refractive indexes on the glass surface, and antireflection is achieved by the optical interference action between the layers. In considering this antireflection mechanism, the simplest single-layer vapor deposition film is taken as an example. When a material having a refractive index Nf lower than that of glass is coated on a glass surface having a refractive index Ng with a thickness d, the reflection behavior of light incident on this surface can be derived by the Fresnel formula, and the reflectance R is Expression "Number 1"
It is represented by.

[0012]

[Equation 1]

[0013]

[Equation 2]

From the above equation, Nf is the square root Ng and R = 0, and there is no reflected light at all for the light of wavelength λ. The most common soda glass has Ng = 1.52, so Nf = 1.23
By coating with the substance (1), an ideal antireflection film with a wavelength λ determined by the film thickness d is obtained. However, no substance with such a low refractive index actually exists, and magnesium fluoride with Nf = 1.38 is currently available.
(MgF ₂ ) has the lowest refractive index.

In this case, the reflectance is R = 1.3%. The antireflection condition of the monolayer film is for a certain specific wavelength λ, as is clear from “Equation 1” and “Equation 2”, and the reflectance increases before and after λ. Therefore, the entire visible light range (40
In order to reduce the reflection at 0 to 700 nm), it was necessary to stack many layers of substances having different refractive indexes while strictly controlling the film thickness. On the other hand, a non-uniform film having a refractive index distribution in the film thickness direction can also reduce surface reflection. Now, in the case where the glass surface has irregularities as shown in FIG. 10, the refractive index (nF (x)) can be expressed by the formula "Equation 3", where x is the coordinate in the depth direction of this layer.

[0016]

[Equation 3]

Here, ng is the refractive index of the glass, V (x) is the volume occupied by the glass at x, and n ₀ is the refractive index of air. ◆ In this case, the refractive index changes discontinuously at the interface between the air and the film and the interface between the film and the glass substrate as shown in FIG. 11, so let the refractive indices at this point be n ₁ and n ₂ , respectively. ,
The reflectance R of this layer can be expressed by the equation "Equation 4".

[0018]

[Equation 4]

In this equation, n ₀ = 1.0 (refractive index of air),
FIG. 12 shows the reflectance at the visible light wavelength, where n ₁ = 1.1, n ₂ = 1.47, and ng = 1.53 (refractive index of glass). The lowest reflectance can be obtained from the figure because the surface roughness is 100 nm (0.1 μm).
It is clear that it is about m). However, it is difficult to form irregularities of this size regularly on the glass surface, and much time is required even by the etching method. The inventors of the present invention have proposed a film having low reflection characteristics comparable to a three-layer vapor-deposited film by forming the unevenness with ultrafine particles. In this case, the obtained reflectance is about 0.2 ~
It was 0.3%. The antireflection film formed by the unevenness of the ultrafine particles has not only antireflection properties but also resolution and contrast characteristics comparable to those of the three-layer vapor deposition film. However, when stains such as fingerprints are attached, there is a problem that the stains get into the irregularities and are difficult to remove.

As a result of further intensive study, a treatment agent for forming a water-repellent film containing a silyl compound selected from the group consisting of a chlorosilane compound, an alkoxysilane compound and a fluoroalkylsilane compound was applied to the uneven surface. It has been found that by forming an ultrathin film, preferably a monolayer so as to leave the irregularities of the ultrafine particles, it is possible to significantly improve the antifouling property without impairing the optical and electrical properties.

An object of the present invention is to provide a visible light antireflection film, an antistatic film and / or an infrared reflection film which are low in cost, hard to be stained, and applicable to a large area, and an image display device to which the same is applied. It is in.

[0022]

The above-mentioned object is to form at least one or more films formed on the surface of a substrate by ultrafine particles and a binder filling a space between the ultrafine particles constituting the ultrafine particle group, and forming the surface thereof. This is achieved by providing a layer having water repellency.

The water-repellent layer also has oil repellency, is composed of a silyl compound, has a surface with minute irregularities, has a film thickness of 10 nm or less, and has a CH ₃ group or CF ₃ group on the surface. Any material having at least one of those having a contact angle of 90 ° or more on the surface may be used.

The water-repellent layer may be formed by forming one molecular layer on the surface of the ultrafine particle layer formed by at least one layer of the ultrafine particle group and the binder. In addition, the depth of minute irregularities is 20 to 100 nm. The ultrafine particles that form the surface irregularities are the ultrafine particles for preventing visible light reflection.

The ultrafine particles include those for preventing visible light reflection from the group of silicon dioxide (SiO ₂ ) and magnesium fluoride (MgF ₂ ), and those for antistatic are tin dioxide (SnO ₂ ), SnO ₂ + oxidation. Antimony (Sb ₂ O ₃ ), Indium oxide (In ₂ O ₃ ), In ₂ O ₃ +
Ultrafine particles for further infrared radiation reflecting from the group of SnO ₂ is SnO _2, SnO ₂ +
It is selected from the group consisting of Sb ₂ O ₃ , In ₂ O ₃ , In ₂ O ₃ + SnO ₂ , titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ). ◆ When the substrate is glass, Si (OR) ₄ (R is an alkyl group) is used as a binder. When the substrate is plastic,
It is preferable to use Si (OR) ₄ (R is an alkyl group) as a binder and a coupling agent having a functional group for plastics, and further pretreat the substrate with alkali and / or hydrofluoric acid. ◆ Also, the coupling agent is preferably γ-methacryloxypropyltrimethoxysilane when the plastic is an acrylic resin, and γ-glycidoxypropyltrimethoxysilane when the plastic is an epoxy resin.

The ultrafine particle film may be formed on both sides of the substrate or only on one side. ◆ It is preferable that the ultrafine particles for preventing visible light reflection are made of SiO ₂ ultrafine particles having a particle size of 40 nm to 200 nm, and the antistatic ultrafine particles are made of a tin oxide compound having a particle size of 10 nm or less. Further, the substrate on which the ultrafine particle film is formed by the above method is a transparent plate, and the transparent plate may be provided in a liquid crystal panel, a window glass for automobiles or a protective plate for exhibition. ◆ Alternatively, an ultrafine particle film may be formed on the transparent substrate by the above method to serve as an image display plate or an image display protection plate,
Further, the image display plate or the image display protection plate may be provided in the cathode ray tube. The transparent plate, the first side of the substrate side of the ultrafine particle film formed on the surface of the image display plate and the image display protection plate,
It is preferable to contain antistatic ultrafine particles or infrared reflective ultrafine particles. ◆ Also, the outermost layer is preferably made of ultrafine particles for preventing visible light reflection. The substrate described above is not limited to a flat plate, but includes a substrate having a surface on which an ultrafine particle film is formed.

A silyl compound may be used as the water repellent treatment agent.

As the silyl compound, a treating agent containing at least one of a chlorosilane compound, an alkoxysilane compound and a fluoroalkylsilane compound is used. Examples of the chlorosilane compound include CH ₃ SiC
_{l 3, (CH 3) HSiCl} 2, (CH 3) 2 SiCl 2, and the like (CH _{3) 3} SiCl. ◆ Examples of alkoxysilane compounds include CH
₃ Si (OCH ₃ ) ₃ , (CH ₃ ) ₂ Si (OCH ₃ ) ₂ , CH ₃ Si (OC ₂ H ₅ ) ₃ , (CH ₃ ) ₂
Si (OC ₂ H ₅ ) _{2 and the} like can be mentioned.

Examples of the fluoroalkylsilane compound include CF ₃ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , CF ₃ CH ₂ CH ₂ SiCl ₃ , CF
Such as _{3 (CF 2) 7 CH 2} CH 2 SiCH 3 Cl 2 and the like.

When the silyl compound is treated on the ultrafine particle film formed by the ultrafine particles and the binder, a special pretreatment is performed because both the ultrafine particles and the binder have a large amount of hydroxyl groups on their surfaces. Even if it does not exist, it can be easily reacted to form a siloxane bond.

In the case of a fuming solvent such as (CH ₃ ) ₂ SiCl ₂ which is a chlorosilane compound, the method for treating the water repellent agent to form a layer having water repellency is to apply the vapor to the ultrafine particle film. Good. Further, the alkoxysilane compound and the fluoroalkylsilane compound can also be treated on the substrate on which the ultrafine particle film has been applied, by using a usual coating method such as a spray method, a spin method or a dipping method.

The ultrafine particle film obtained as described above is
It has good anti-reflection and anti-static properties as well as excellent stain resistance.

[0033]

In general, when a film is formed by a dipping method using a coating solution in which ultrafine particles are not mixed, the following formula "Equation 5" may be established between the film thickness t and the pulling speed v. Are known.

[0034]

[Equation 5]

Where η is the viscosity of the solution, p is the density of the solution,
g is gravitational acceleration, and K is a constant.

On the other hand, when the coating liquid containing relatively large ultrafine particles (40 to 200 nm) for antireflection is raised or lowered on the substrate surface at a constant speed, the present inventors It was found that the morphology of the array of ultrafine particles varies greatly depending on the surface condition. For example, even in the same commercially available flat glass, the arrangement form is different between the front and the back, and the reflection characteristics change. When the surface condition of this type of plate glass was analyzed by a surface analyzer such as an X-ray photoelectron spectroscopy analyzer (XPS), a large amount of tin oxide (SiO ₂ ) was detected from the surface on one side. It is considered that this is due to the fact that tin adheres to the glass when the molten glass passes over the tin bath in the process of manufacturing the plate glass. It is difficult to remove the adhered SiO _{2 even if} the glass cleaning pretreatment is performed. It has been found that when the ultrafine particle mixed solution is applied to a substrate having such a surface state, it can be applied thinly because the wettability is different from that of ordinary glass. In other words, if the same film thickness is to be obtained, the coating speed can be increased from "Equation 5". If the coating speed is high, the coating time is naturally shortened and the manufacturing cost is low.

Further, as described above, when the material of the substrate is different, the surface condition is also different, so that the wettability is changed and the film thickness of the ultrafine particle film is changed. Therefore, in order to obtain the same film thickness and the arrangement state of ultrafine particles, the coating conditions must be changed each time. In particular, since glass and plastics have completely different surface states, it is necessary to consider them from the pretreatment step. However, in the present invention, small oxide ultrafine particles (10 nm or less) such as SnO ₂ and indium oxide (In ₂ O ₃ ) are previously applied as antistatic and / or infrared reflecting ultrafine particles, so that the surface state of the substrate or the substrate Even if the material is different, a constant surface condition can be always obtained. Therefore, the same characteristics can be obtained under similar coating conditions. At this time, even in the case of a solution in which ultrafine particles with a particle size of about 10 nm are mixed, the array state of the ultrafine particles changes depending on the surface state of the substrate, but they are regularly arrayed like an ultrafine particle film for antireflection. Since it is not necessary, almost constant characteristics (antistatic or infrared reflection characteristics) even with similar pretreatment
Is obtained.

Further, when the above-mentioned silane compound is subjected to a water-repellent treatment, the active hydrogen of the hydroxyl groups on the surface of the ultrafine particles and the binder is replaced with a silyl group, so that the outermost layer has only CH ₃ groups or CF ₃ groups and is water-repellent.

When the surface of the ultrafine particle film of the present invention has irregularities, when the contact angle between water and the surface is 90 ° or less, it further exhibits hydrophilicity and becomes wet well. However, when the contact angle is 90 ° or more, the apparent contact angle becomes large and the water repellency becomes remarkable. Therefore, when the contact angle is 90 ° or more by applying the water repellency treatment, the water repellency is superior to that of a normal flat plate. This tendency is the same for oils, and it exhibits excellent oil repellency. Therefore, it is also effective against stains such as fingerprints containing oil.
The water repellent layer is more effective than forming it on the surface of the ultrafine particle film having unevenness as described above, and the film surface formed by the visible light antireflection ultrafine particle size 40 nm to 200 nm that forms the unevenness. Considering the minimum value of 20 nm of the depth of the valleys of the unevenness, the thickness is preferably 10 nm or less.

[0040]

Embodiments of the present invention will be described below with reference to the drawings. First, the constituent features of the present invention will be divided.

(Ultrafine Particles) The function of the ultrafine particles is not particularly limited as long as it does not affect the transparency and translucency, but refers to those having an average particle size of submicron. Typical functions are antireflection of visible light, antistatic and / or infrared reflection.

Ultrafine particles for antireflection are silicon dioxide (Si
O ₂ ), preferably SiO ₂ ultrafine particles having voids or MgF ₂ is desirably selected. Ultrafine particles for antistatic
SnO ₂ , SnO ₂ + antimony oxide (Sb ₂ O ₃ ), In ₂ O ₃ , In ₂ O ₃ + S
It is preferably selected from the group of nO ₂ . The infrared-reflecting ultrafine particles are preferably selected from the group consisting of In ₂ O ₃ , In ₂ O ₃ + SnO ₂ , titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ).

The average particle size of the antireflection ultrafine particles is 40 to
200nm is desirable. With ultrafine particles having a particle size smaller than 40 nm, the outermost surface of the formed film becomes too flat and a sufficient antireflection effect cannot be obtained. On the other hand, ultrafine particles having a particle size larger than 200 nm can sufficiently obtain the antireflection effect, but the diffuse reflection becomes large, and as a result, the cloudiness may occur and the resolution may decrease at the same time. Therefore, the particle size of the antireflection ultrafine particles is preferably 40 to 200 nm. From this, the depth of the valley formed between the ultrafine particles is preferably 20 to 100 nm. Incidentally, SiO
_The ultrafine particle material for antireflection such as ₂ and MgF ₂ has a refractive index of 1.50 or less.

The average particle size of the antistatic ultrafine particles is preferably 10 nm or less. Also, two or more kinds of antistatic ultrafine particles may be used in combination. When ultrafine particles having an average particle diameter of 10 nm or less are mixed with the coating liquid, a relatively uniform film can be obtained even if the surface state of the substrate is different. Moreover, even if it is applied to a considerably thick layer, it is relatively unlikely to cause a decrease in transmittance and cloudiness.

Ultrafine particles having an antistatic function, an infrared reflecting function or an electromagnetic shielding function include SnO ₂ , In ₂ O ₃ and T
Examples thereof include metal oxides such as iO ₂ and ZrO ₂ , or mixtures thereof. Of these, SnO ₂ +10 wt% Sb ₂ O ₃ or In ₂ O
₃ +5 wt% SnO ₂ is preferable because it has excellent antistatic properties and infrared reflection properties. Thickness is 0.1-0.5μm, particle size is 5-50nm
Is desirable. Metal oxides or their mixtures with antistatic function have energy-bandgap of 3 eV
Because of the above, it shows high transparency in the visible light region,
It exhibits high conductivity due to deviation from stoichiometric composition and high free electron concentration due to impurity addition. Further, even if the ultrafine particles are not in direct contact with each other, in other words, even if a binder or the like is present between the ultrafine particles, if the thickness is thin, conductivity is exhibited by the tunnel effect. In order to have an antistatic function, conductivity of about 10 ⁶ to 10 ⁹ Ω / cm ² is sufficient, so that the mixing ratio of these ultrafine particles and the binder can be set in a relatively wide range.

(Translucent Substrate) ◆ The translucent substrate may be a glass plate, a plastics plate or a plastics film. Examples of the plastic material include those whose main component is polyethylene, polypropylene, urethane, acryl, phenol, epoxy, melanin, nylon, polyimide, polycarbonate, butyl, epoxyphenol, vinyl chloride, polyester and the like. The surface of the substrate on which the ultrafine particles are formed may be a flat plate or may have a curvature like a cathode ray tube. Further, the surface on which the ultrafine particles are formed may be either one surface or both surfaces.

(Pretreatment) Considering the wettability with the substrate, pretreatment such as alkali treatment or hydrofluoric acid treatment is preferable. In the case of a plastic substrate, pretreatment with a neutral detergent is also effective.

(Coating method) ◆ It is desirable that the coating liquid should cover the object to be coated such as the substrate and then expose it at a speed of 10 mm / s or less.
Further, this speed may be constant or may be changed depending on the shape of the object to be coated. The substrate may be installed in the container, or alternatively, the substrate surface may be exposed through a hole formed in the side surface of the container. The latter method is suitable for forming an ultrafine particle film on an almost finished product such as a cathode ray tube.

The heating of the coated surface is carried out in a furnace at 50 to 200
Although it is practical to bake at ℃, it may be fired in a short time by ultraviolet rays using a high pressure mercury lamp or the like.

Although the example of the dipping method has been described above, the dipping method, the spin coating method, and the spray method are not limited to this dipping method as long as the application method to the plastics substrate and the uniformity of the film surface are not required. Alternatively, a combination of these and a combination of these and the dipping method are also effective.

(Coating Solution) ◆ In order to form the ultrafine particle film of the present invention, a coating solution in which a predetermined amount of ultrafine particles are added with a binder and, if necessary, a coupling agent and other additives is used. ◆ When the translucent plate is glass, it is used as a binder
It is preferable to use Si (OR) ₄ (where R is an alkyl group), and when the light-transmissive plate is plastics, Si (OR) x (X = 2 to 4, preferably 3) is used as a binder. It is preferable. Further, when the translucent plate is made of plastics, it is desirable to use a coupling agent having a functional group for the plastics material together. ◆ Easily reacts with alcohol solution in which Si (OR) ₄ (where R is an alkyl group) is dissolved when the translucent plate is glass, and with this polymer when the translucent plate is plastics. A silane coupling agent having a functional group and Si (OR) x (X = 2 to 4, preferably 3), or an alcohol solution in which a mixed solution of the Si (OR) ₄ and the silane coupling agent is dissolved. Disperse the ultrafine particles.

After the substrate is coated on the transparent plate by the above method, the coated surface is heated (or fired) to form a film. By this heat treatment, Si (OR) ₄ or the silane coupling agent is decomposed to serve as an adhesive between the ultrafine particles such as SiO ₂ and the substrate. As R of Si (OR) ₄ , an alkyl group having 1 to 5 carbon atoms is generally preferable. on the other hand,
The silane coupling agent needs to be appropriately selected depending on the polymer material of the transparent plate. For example, when the main component is polyethylene, polypropylene, urethane, acrylic or the like, a silane coupling agent such as vinyltriethoxysilane or γ-methacryloxypropyltrimethoxysilane is effective. In the case of phenol, epoxy, melanin, nylon, polyimide, and polycarbonate, silane coupling agents such as γ-aminopropylethoxysilane and γ-glycidoxypropyltrimethoxysilane are effective. Further, in the case of butyl, epoxyphenol, vinyl chloride and polyester, silane coupling agents such as β, 3,4-epoxycyclohexylethyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane are effective.

Further, the alcohol for melting Si (OR) ₄ or the silane coupling agent becomes too viscous in view of workability because the viscosity of the mixed alcohol solution becomes high as the number of carbon atoms of R is increased. Alcohol may be appropriately selected so as not to exist. ◆ Generally usable alcohols include alcohols having 1 to 5 carbon atoms.
Further, since the Si (OR) ₄ is hydrolyzed, a coating solution may be prepared by adding water and a mineral acid such as nitric acid as a catalyst.

(Water / Oil Repellent Treatment Agent) The water / oil repellent treatment agent is selected from the group containing silyl compounds such as chlorosilane compounds, alkoxysilane compounds and fluoroalkyl silane compounds. When the silyl compound has a low viscosity, it can be directly used as a treating agent.
When it has a high viscosity, it can be prepared and used in the same manner as the coating solution. As the treatment method, it is only necessary to put the substrate on which the ultrafine particle film is provided in a container filled with the vapor of the treatment agent for a certain period of time. Further, as in the case of the coating method, the treatment agent may be used in a liquid state and may be coated by a dipping method, a spin coating method, a spray method or the like.

Examples in which the present invention is applied to the front panel surface (glass face plate) of a cathode ray tube will be described below. ◆ FIG. 1 is a process diagram of this embodiment. First, the surface of the cathode ray tube is washed with alkali, washed with pure water, and then blown with nitrogen gas or the like so that no traces of water drops remain. Next, this Braun tube is mounted on a coating device, and a coating liquid mixed with conductive ultrafine particles is coated. The coating device and coating method will be described later. An example of the composition of the mixed coating solution and the coating conditions at this time is shown in Table 1. After the application, the cathode ray tube is detached from the apparatus after being left for a predetermined time, and dried with nitrogen gas. Drying may be cold air drying with gas or clean air, hot air drying, or oven drying. After drying, attach it to another coating device with the same specifications,
A coating solution containing ultrafine particles for antireflection is applied. Next, this cathode ray tube is placed in a closed container filled with vapor of a chlorosilane compound for a predetermined time, and then dried in the same manner as the above method. An example of the composition of the mixed coating solution, the water-repellent oil treating agent and the coating conditions at this time is shown in "Table 1".

[0056]

[Table 1]

Next, it is baked in a furnace at 160 ° C. for 30 minutes. The firing may be heating in a furnace or heating by ultraviolet rays or infrared rays. By this firing step, the ultrafine particles are firmly adhered to the cathode ray tube. Through the above coating process, an antistatic film, an antireflection film and a film having water repellency are formed.

FIG. 2 is a diagram showing the construction of the coating apparatus of this embodiment. In FIG. 2, 21 is a cathode ray tube, 22 is a coating solution tank, 23 is a coating solution, 24 is a solution supply valve, 25 is a drawing valve, 26 is a metering pump, 27 is a solution tank, 28 is a solution supply pressurizing valve, 29 is a leak valve. ◆ In such a configuration, the cathode ray tube 21 is attached to the coating liquid tank 22. In this case, the mounting surface of the coating liquid tank 22 is provided with packing or an O-ring to prevent the coating liquid from leaking in the coating process, and has a structure that can be sealed simply by pressing the CRT in consideration of workability. Has become.

Next, the coating solution in which the ultrafine particles are mixed is introduced into the space formed between the coating liquid tank 22 and the surface of the cathode ray tube. To introduce the coating liquid, first, the extraction valve 25 and the leak valve 29 are closed, and the solution supply valve 24 and the solution supply pressurization valve 28 are opened. Solution supply pressurizing valve 28
Is connected to an air compressor, and the compressed air generated by the air compressor is gradually added to the solution tank. By this operation, the coating solution 23 filled in the solution tank 27 is filled on the surface of the cathode ray tube. Next, after closing the solution supply valve 24 and the solution supply pressurization valve 28, the withdrawal valve 25 and the leak valve 29 are opened, and the metering pump 26 is activated to apply the coating solution 23 filled on the surface of the cathode ray tube. Is the solution tank
Returned to 27. In this case, the speed at which the coating solution 23 descends on the surface of the cathode ray tube can be adjusted by appropriately changing the liquid feed rate of the metering pump 26. When filling the coating solution between browns, in addition to compressed air, an inert gas such as
N ² gas may be used.

Next, a method of mixing the coating solution will be described. First, the coating solution for the antistatic film applied to the first layer is ethyl silicate [Si (OC ₂ H ₅ ) ₄ ] dissolved in ethanol,
Further, a solution containing H ₂ O for hydrolysis and HNO ₃ as a catalyst is prepared, and 2% by weight of SnO ₂ ultrafine particles having a particle size of 6 nm is added to this solution. The antireflection coating solution to be applied to the second layer was prepared by dissolving ethyl silicate [Si (OC ₂ H ₅ ) ₄ ] in ethanol, and further adding H ₂ O for hydrolysis and HNO ₃ as a catalyst. Make the added solution and add 12
Add 5% by weight of 0 nm SiO ₂ ultrafine particles. At this time, the pH of the solution is adjusted so that it is sufficiently dispersed.

Next, the surface of the cathode ray tube was filled with the coating solution for the antistatic film by the above-mentioned method, and the coating solution was dropped at a rate of 3.0 mm / s for coating. After coating, it was forcedly dried with cold air. Next, an antireflection coating solution was applied on the above in the same manner to form an ultrafine particle film. The coating speed at this time is 2.5 mm / s. Next, the surface of the ultrafine particle film was subjected to water repellent treatment by leaving it in a container filled with vapor of a chlorosilane compound as a water repellent treatment agent. Then, it was baked in air at 160 ° C. for 30 minutes to decompose ethyl silicate. Added to the solution
SnO ₂ and SiO ₂ ultrafine particles, SiO ₂ was Deki by decomposition because serves binder, firmly adhered to the CRT surface, are fixed. Moreover, since the SnO ₂ ultrafine particles are uniformly dispersed and applied to the surface of the first layer, the wettability is good and uniform.

Therefore, the second-layer SiO ₂ ultrafine particles can be uniformly arranged to form continuous irregularities. Furthermore, the chlorosilane compound, which is a water repellent treatment agent, converts the active hydrogen of the hydroxyl group (OH) on the ultrafine particles and the binder surface into the silyl group (R ₃ Si).
Replace with (silylation). For example, in the case of trimethylchlorosilane (Me ₃ SiCl), when it reacts with Si-OH on the surface of ultrafine particles, Si-OH + Me ₃ SiCl becomes Si-OSiMe ₃ + HCl, and the outermost layer is Me ₃
Therefore, it becomes water repellent. This reaction is
It has water repellency because the monolayer adheres firmly and the outermost layer is composed of only CH ₃ groups. Therefore, the depth of the valley formed by the ultrafine particles and the ultrafine particles hardly changes from that before the treatment. Therefore, the antireflection effect does not change as described above.

In FIG. 3, a glass plate of the same material as the cathode ray tube is coated with this film, and the film is broken and its cross section is taken by a scanning electron microscope (S
It is a perspective view which represented typically the result observed by EM). 120 nm SiO ₂ ultrafine particles 33 are further arranged on a first-layer conductive film 32 formed on a glass plate 31 with a substantially uniform film thickness. There is a part where some ultrafine particles are missing, but this size is equivalent to a few ultrafine particles, that is, a distance of about 240 to 360 nm, which is sufficiently smaller than the wavelength of visible light, and therefore has a large reflection characteristic. There is no effect. ◆ As a result of measuring the reflectance by making light incident on the surface of the cathode ray tube having this film at an incident angle of 5 °, a low reflectance of 0.3% was obtained at a wavelength of 550 nm as shown in FIG.

On the other hand, as a result of measuring the surface resistance value of this film, it was about 10 ⁸ Ω / □, and this charging characteristic is, as shown in FIG. 5, compared with the conventional characteristic (untreated product) shown as a reference. It turns out that it is hardly charged. At this time, a thin insulating binder exists between the conductive ultrafine particles, but it is known that electrons move in the substance such as SnO ₂ due to the tunnel effect. Is demonstrated.

Next, as a result of rubbing the antistatic low-reflection film of this embodiment with an eraser (Lion Co., 50-30 type) 50 times under a load of 1 kgf, the reflectance was changed by about 0.1%. There was no problem in film quality. Moreover, as a result of pressing the finger strongly against the film to attach the fingerprint and wiping with a cloth soaked in ethyl alcohol, it was possible to remove all.

In the process of forming such an electrification / antireflection film, the film can be directly formed on the completed cathode ray tube, and SnO ₂ ultrafine particles or SiO ₂ ultrafine particles can be added to the existing Si (OR) ₄ alcohol solution. It suffices to mix and apply and to apply, and it is possible to manufacture with constant quality and at low cost. Also, in the above embodiment, R is used as Si (OR) _4.
Shows an example of an ethyl group, but as described above, R = CnHm (m = 2n + 1)
In such a case, it is possible to carry out in the range of n = 1 to 5, and when n becomes large, the viscosity of the solution becomes a little high, and therefore, as the solvent, alcohol corresponding to it may be selected in consideration of workability.

As described above, according to this embodiment, an image display plate having a film having an excellent antireflection effect and an antistatic function can be formed by a simple apparatus and a simple coating process. Therefore, the display board of this embodiment is suitable for mass production and has excellent stain resistance.

Another embodiment will be described with reference to FIG.
◆ FIG. 6 shows a device configuration of this embodiment. In FIG. 6, reference numeral 61 denotes a transparent substrate, and a plurality of transparent substrates are set on the jig 62 and housed in the coating liquid tank 22. The transparent substrate of the cathode ray tube of the first embodiment is a glass plate, whereas the transparent substrate 61 is a plastic plate. In this case, a packing or an O-ring is provided at the entrance and exit provided in the coating liquid tank 22 so that the jig and the article to be coated are taken in and out, so that the coating solution does not leak during the coating process. Next, the coating solution containing the ultrafine particles was introduced into the space of the coating liquid tank 22. To introduce this coating liquid, first of all, withdrawal valve
25 and leak valve 29 closed, supply valve valve
24 and the solution supply pressure valve 28 are opened. By this operation, the coating solution 23 filled in the solution tank 27 is pressurized to fill the coating solution tank 22.

Next, after closing the solution supply valve 24 and the solution supply pressurization valve 28, the withdrawal valve 25 and the leak valve 29 are opened, and the metering pump 26 is activated.
The coating solution 23 filled in is returned to the solution tank 27. In this case, by appropriately changing the feed rate of the metering pump 26, the speed of the coating solution 23 can be adjusted so as to descend at a predetermined rate on each surface of the transparent substrates 61. The coating process in this case is almost the same as that in FIG. 1, except that the process of installing the cathode ray tube sets the jig 62 in the coating liquid tank 61, and the process of removing the cathode ray tube separates the jig 62 from the coating liquid tank 61. It becomes the process of installing in the coating device. In the case of three-layer coating, three different types of coating liquids and three coating devices having the same specifications are used for coating.

Next, a method for mixing the coating solution will be described. ◆ The coating solution for the antistatic film, which is applied on the first layer, is
A solution prepared by dissolving ethyl silicate [Si (OC ₂ H ₅ ) ₃ ] containing γ-methacryloxypropyltrimethoxysilane in ethanol, and further adding H ₂ O for hydrolysis and HNO ₃ as a catalyst was prepared. 2% by weight of SnO ₂ ultrafine particles having a particle size of 6 nm is added to this solution. Next, the antireflection coating solution to be applied to the second layer is a solution of ethyl silicate [Si (OC ₂ H ₅ ) ₄ ] dissolved in ethanol, H ₂ O for hydrolysis, and HNO ₃ as a catalyst. 5% by weight of SiO ₂ ultrafine particles having a particle diameter of 40 nm is added to the solution. At this time, the pH of the solution is adjusted so that it is sufficiently dispersed. Further, a fluoroalkoxysilane compound is used as a water and oil repellent treatment agent. Next, these three kinds of coating solutions were sequentially coated using the apparatus shown in FIG. "Table 2" shows the coating conditions at this time.

[0071]

[Table 2]

After completion of the three coating steps, baking was carried out at 50 to 120 ° C. depending on the type of plastic. FIG. 7 is a schematic view showing the result of rupturing the substrate 11 coated with this film and observing its cross section by SEM. An antistatic layer 72 of the first layer is formed on the surface of the substrate 71, and an antireflection layer 74 is formed thereon with a substantially uniform thickness, and the antireflection function is the same as that of the glass substrate. Further, a fluoroalkoxysilane compound reacts on the surface of the outermost layer, and CH ₃ is uniformly thinly overcoated as a layer 75 having water repellency as described above.
In addition, 73 is a binder. As a result, a film excellent in antireflection function, antistatic function, abrasion resistance, durability and stain removability was formed. Although the ultrafine particle film having a three-layer structure has been described in the present embodiment, the formation of an ultrafine particle film having four or more layers can be performed by adding the above-mentioned coating step.

FIG. 8 is a partial sectional perspective view showing an example in which this ultrafine particle film is applied to the surface of a liquid crystal panel. A common electrode 85 is provided adjacent to one of the layers of the liquid crystal 86, and a glass substrate 83 and a polarizing plate 82 are laminated on the common electrode 85. A glass substrate 811 and a polarizing plate 812 are laminated on the other layer of the liquid crystal 86. Glass substrate
Pixel electrodes 87 are formed in minute areas on 811 at positions facing pixels 841 formed on the color filter layer, respectively. The ultrafine particle film 81 of the present invention was applied to the surface of the deflection plate 82 of the liquid crystal panel having such a structure. When the liquid crystal panel provided with the ultrafine particle film of this embodiment is used in a liquid crystal display device (TFT) such as a personal computer shown in FIG. 14, the resolution of the image displayed on the liquid crystal panel 87 is improved. ◆ Conventionally, the surface of a liquid crystal display plate is provided with, for example, micron-order unevenness to diffuse the reflection on the surface. In such a process, the image formation by the reflected light disappears, but there is a problem that the original image is blurred and the resolution is lowered or the contrast is lost due to the diffuse reflection. Was one of the causes. On the other hand, in the present embodiment, such a problem does not occur because the reflection is almost prevented as described above. 65 to 70 in the conventional method
Only / cm can be detected by the human eye, but in the present embodiment, 85 lines / cm or more, which is the limit of the resolution of the human eye, can be detected. Further, FIG. 13 shows an example in which the ultrafine particle film of the present invention is applied to an automobile window glass. If water droplets or a non-uniform water film is formed on a window glass for an automobile, especially on the windshield 131, the visibility is deteriorated, which is a safety problem. Therefore, a method of removing water with a wiper has been mainly used so far. Recently, water repellent treatments are available on the market and can be easily treated.However, those treated with water repellent have a contact angle of about 90 degrees, and water droplets are not generated by wind pressure for the first time at 60 km / h or more. To be removed. On the other hand, in the case of the glass coated with the ultrafine particle film of the present invention, the contact angle is around 130 degrees, so that the speed is 4
It can be removed even at 0 km / h or less, which is preferable for safety. Such water drop removal effect is not limited to windshield
It can be used for 2 and rear glass 133.

On the other hand, a transparent plate (mainly glass or plastic) provided as a protection in front of a work of art such as a painting in a museum or the like should be reflected by lighting or other objects, and the work of art inside cannot be seen well. Is a good experience every day. Therefore, although lighting or lighting is devised, it may not be effective depending on the viewing angle, and it may be almost invisible. In general, many transparent plates used for arts have a large size, and it is often physically difficult to apply, for example, a three-layer vapor-deposited film conventionally used as an antireflection film. Further, even if a transparent plate of a large size can be coated with a film, the device becomes large and expensive. On the other hand, when the method of the present invention is used, it is possible to easily apply a film even for a large size product. Further, the film has the same antireflection property as that of the three-layer vapor-deposited film and has good stain resistance. Therefore, according to the present invention, there is an effect that it is possible to easily manufacture a transparent protective plate for protecting a large-sized work of art, which has been difficult in the past.

[0075]

According to the present invention, it is possible to easily form a visible light antireflection film, an antistatic film and / or an infrared reflection film having excellent adhesion to stains on an article by a simple coating method using ultrafine particles. Can be formed.

[Brief description of drawings]

FIG. 1 is a film forming process diagram according to an embodiment of the present invention.

FIG. 2 is a device configuration diagram according to an embodiment of the present invention.

FIG. 3 is a sectional perspective view of an ultrafine particle film according to an embodiment of the present invention.

FIG. 4 is a reflection characteristic diagram when the ultrafine particle film of the present invention is applied to an antireflection film.

FIG. 5 is a charging characteristic diagram when the ultrafine particle film of the present invention is applied to an antistatic film.

FIG. 6 is a device configuration diagram according to another embodiment of the present invention.

FIG. 7 is a cross-sectional view of an ultrafine particle film according to another embodiment of the present invention.

FIG. 8 is a partial cross-sectional perspective view of a liquid crystal panel that is an application example of the present invention.

FIG. 9 is a general cross-sectional view of a CRT as an application example of the present invention.

FIG. 10 is an explanatory view of the antireflection principle of the present invention.

FIG. 11 is an explanatory view of the antireflection principle of the present invention.

FIG. 12 is a reflection characteristic diagram for explaining the antireflection principle of the present invention.

FIG. 13 is an external view of an automobile to which the present invention is applied.

FIG. 14 is a perspective view of a personal computer using a liquid crystal panel which is an application example of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ultrafine particle layer, 2 ... Glass plate, 3 ... Conductive film, 4 ... Antireflection layer, 5 ... Ultrafine particle, 21 ... Braun tube, 22 ... Coating solution tank, 23 ... Coating solution, 24 ... Solution supply valve, Two
5 ... Extraction valve, 26 ... Metering pump, 27 ... Solution tank, 28 ... Solution supply pressure valve, 30 ... Visible light antireflection layer, 31 ... Glass plate, 32 ... Conductive film, 33 ... Ultra fine particles, 91 ... CRT, 92 ... CRT inner surface, 93
... Phosphor, 94 ... Aluminum film, 95 ... CRT front panel.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01J 29/89

Claims (33)

[Claims] 1. A film formed on the surface of a substrate, wherein the film is formed by at least one layer of ultrafine particles and a binder filling the space between the ultrafine particles constituting the ultrafine particles, and the film is repelled on the surface. An ultrafine particle film having a water-soluble layer. 2. The ultrafine particle film according to claim 1, wherein the water-repellent layer also serves as oil repellency. 3. The ultrafine particle film according to claim 1, wherein the water-repellent layer is made of a silyl compound. 4. The layer having water repellency is characterized in that the surface thereof presents minute irregularities.
The ultrafine particle film described in 1. 5. The ultrafine particle film according to claim 4, wherein the water-repellent layer has a film thickness of 10 nm or less. 6. The ultrafine particle film according to claim 1, wherein the surface of the water-repellent layer has a CH ₃ group or a CF ₃ group. 7. The ultrafine particle film has a surface contact angle of 90 °.
7. The ultrafine particle film according to any one of claims 1 to 6, which is the above. 8. The ultrafine particle film according to claim 1, wherein the water-repellent layer is formed as a monolayer on the surface of the ultrafine particle layer formed by at least one layer of the ultrafine particle group and the binder. . 9. The ultrafine particle film according to claim 4, wherein the depth of the fine irregularities is 20 to 100 nm. 10. The ultrafine particle film according to claim 9, wherein the ultrafine particles forming the surface irregularities are ultrafine particles for preventing visible light reflection. 11. The ultrafine particles for preventing visible light reflection have a particle size of 40.
11. The ultrafine particle film according to claim 10, wherein the ultrafine particle is SiO ₂ ultrafine particles having a size of nm to 200 nm. 12. A transparent plate having an ultrafine particle film on at least one surface of a transparent substrate, wherein the ultrafine particle film is as defined in any one of claims 1 to 11. . 13. A transparent plate having an ultrafine particle film on at least one surface of a transparent substrate, wherein the ultrafine particle film is composed of multiple layers, and the first layer on the transparent substrate side is ultrafine particles for antistatic or infrared reflection. A transparent plate comprising ultrafine particles, wherein a layer having water repellency is provided on the surface of the ultrafine particle film. 14. A transparent plate comprising an ultrafine particle film on at least one surface of a transparent substrate, wherein the ultrafine particle film is composed of multiple layers, and the outermost layer contains ultrafine particles for preventing visible light reflection. A transparent plate having a water-repellent layer on the surface of a film. 15. An image display plate comprising an ultrafine particle film on at least one surface of a transparent substrate, wherein the ultrafine particle film is that according to any one of claims 1 to 11. Display board. 16. An image display panel comprising an ultrafine particle film on at least one surface of a transparent substrate, wherein the ultrafine particle film is composed of multiple layers, and the first layer on the transparent substrate side is ultrafine particles for preventing static electricity and / or infrared rays. An image display plate comprising ultrafine particles for reflection, and a layer having water repellency provided on the surface of the ultrafine particle film. 17. An image display plate comprising an ultrafine particle film on at least one surface of a transparent substrate, wherein the ultrafine particle film is composed of multiple layers, and the outermost layer contains ultrafine particles for preventing visible light reflection. An image display plate, wherein a layer having water repellency is provided on the surface of a fine particle film. 18. An image display protection plate having an ultrafine particle film on at least one surface of a transparent substrate, wherein the ultrafine particle film is as defined in any one of claims 1 to 11. Image display protection plate. 19. An image display protective plate comprising an ultrafine particle film on at least one surface of a transparent substrate, wherein the ultrafine particle film is composed of multiple layers, and the first layer on the transparent substrate side is ultrafine particles for preventing electrification or infrared reflection. An image display protective plate comprising ultrafine particles for use, and a layer having water repellency provided on the surface of the ultrafine particle film. 20. An image display protection plate comprising an ultrafine particle film on at least one surface of a transparent substrate, wherein the ultrafine particle film is composed of multiple layers and the outermost layer contains ultrafine particles for preventing visible light reflection. An image display protection plate comprising a water-repellent layer on the surface of a film. 21. A cathode ray tube comprising the image display plate according to any one of claims 15 to 17. 22. A cathode ray tube comprising the image display protection plate according to claim 18. 23. An image display device comprising the cathode ray tube according to claim 21 or 22. 24. A transparent plate according to any one of claims 12 to 14, an image display plate according to any one of claims 15 to 17, and an image display protective plate according to any one of claims 18 to 20. A liquid crystal panel equipped with either. 25. An image display device comprising the liquid crystal panel according to claim 24. 26. An automobile window glass comprising the transparent plate according to any one of claims 12 to 14. 27. An automobile comprising the automobile window glass according to claim 26. 28. An exhibit protection plate comprising the transparent plate according to any one of claims 12 to 14. 29. A method for forming an ultrafine particle film, which comprises forming an ultrafine particle film on a substrate by using an ultrafine particle group and a binder filling a space between the ultrafine particles forming the ultrafine particle group, wherein the ultrafine particle film is formed. The substrate to be placed is placed in a container and a mixed coating solution containing the ultrafine particles and a binder is introduced into the container, and the mixed coating solution is covered from the container after the mixed coating solution covers at least the ultrafine particle film forming portion of the substrate. Is discharged at least twice to form a multilayer ultrafine particle film on the surface of the substrate, and then a water repellent treatment agent is applied to the surface of the ultrafine particle film to form a layer having water repellency. And a method for forming an ultrafine particle film. 30. The method of forming an ultrafine particle film according to claim 29, wherein the rate at which the mixed coating liquid exposes the substrate is 10 mm / s or less. 31. A method for forming an ultrafine particle film, which comprises forming an ultrafine particle film on a substrate by using an ultrafine particle group and a binder filling the space between the respective ultrafine particles forming the ultrafine particle group. Place the substrate to be placed in the container,
As the ultrafine particles, visible light antireflection ultrafine particles, antistatic ultrafine particles and / or infrared reflective ultrafine particles are used.
The mixed coating solution containing the ultrafine particles and the binder is introduced into the container, and the mixed coating solution is discharged at least twice from the container after the mixed coating solution covers the ultrafine particle film forming portion of the substrate. The ultrafine particle film is characterized in that after forming an ultrafine particle film consisting of two layers on the surface of the substrate, a water repellent treatment agent is applied to the surface of the ultrafine particle film to form a water repellent layer. Forming method. 32. The method of forming an ultrafine particle film according to claim 30, wherein the rate at which the mixed coating solution exposes the substrate is 10 mm / s or less. 33. The water repellent treatment agent is one which is silylated with a silyl compound selected from the group consisting of chlorosilane compounds, alkoxysilane compounds and fluoroalkylsilane compounds. The method for forming an ultrafine particle film according to [4].