JP3178009B2 - Anti-reflection body and its utilization device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transparent plate and a method for producing the same,
Also, the present invention relates to a screen display surface plate, a cathode ray tube (cathode tube), and the like, and a method of manufacturing the same, particularly, a transparent plate using ultrafine particles which can effectively function as an anti-reflection film for charging and anti-reflection of an image display plate, and a method of manufacturing the same The present invention also relates to a screen display surface plate, a cathode ray tube (cathode tube), etc. to which this is applied, and a method for producing these.

[0002]

2. Description of the Related Art A film (antireflection film) for reducing the reflectance of the surface of a transparent plate has been studied for a long time and has been used for lenses of cameras, glasses and the like. At present, it is used as an anti-reflection filter for reducing reflected light from a VDT (Visual Display Terminal). Various antireflection films have been considered, but currently used ones are mainly multilayer films and nonuniform films.

A 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 the antireflection effect is a total effect of optical interference effect in each layer. is there. Physics of Multilayer
Shin Film No. 2 (1964), pp. 243 to 284 (Phiysics of Thin Films 2, (1964) p. 243)
284).

A heterogeneous film having a refractive index distribution in the thickness direction becomes an antireflection film when the average refractive index of the film is lower than that of the substrate glass. The heterogeneous film generally has a transparent plate surface made porous.

After forming a metal deposition film on the island on the glass surface,
A method for forming a heterogeneous film by forming fine irregularities by sputter etching and reducing the reflectance is described in Applied Physics Letter No. 36 (1980), pp. 727 to 73.
Page 0 (Apl. Phys. Lett, 36 (1980) p. 727-
730).

[0006] Sawdam glass is also made of SiO ₂ supersaturated H.
Solar energy, No. 6, 1980 (1980) is a method to reduce the reflectance by immersing in ₂ SiF ₆ solution to make the surface porous.
Pages 28 to 34 (Solar Energy 6 (1980) p.
28-p. 34).

On the other hand, in the cathode ray tube, it is required to form a conductive film in order to prevent electrification of the glass surface and also to devise measures for preventing reflection.

It is known that the entire panel surface (image display plate) of a cathode ray tube such as a cathode ray tube is charged. The reason for this is as shown in FIG.
Although a thin and uniform aluminum is deposited on the phosphor 43 coated on the inner surface 42 of the CRT 1, when a high voltage is applied to the aluminum film 44, the cathode ray tube front panel 45 is statically applied at the time of application and cutoff. It is caused by charging phenomenon due to electric induction.

Japanese Patent Application Laid-Open No. 61-51101 discloses a method of forming a charge and antireflection film while also preventing reflection on the display tube surface. In this case, a conductive film is first formed on a glass substrate by a physical vapor deposition method such as a vacuum deposition method or a sputtering method or a chemical vapor deposition method, and an antireflection film is formed thereon. Was.

[0010]

In the above prior art, the method of formation is limited to sputtering and vacuum evaporation, and high precision control of the film thickness is required. There was a problem that is.

In particular, the prior art has a two-layer structure in which a conductive film and an antireflection film are formed respectively, and has problems in productivity and cost. Also, when a film is formed on the surface of a display tube such as a CRT where the film firing temperature is limited to a low temperature, the film strength,
There was a problem with the reflection characteristics.

In the case of a reflection film using ultrafine particles,
The smallest reflectance is obtained when the ultrafine particles are regularly arranged on the substrate at high density.

FIG. 5 is a schematic cross-sectional view showing a case where ultrafine particles are applied on a transparent plate substrate in an orderly and regular manner. 46 is ultrafine particles, 47 is a resin layer, and 48 is a substrate. In this case, n ₀ is the refractive index of air, and n ₁ is the ultrafine particles da on the air side.
N ₂ is the refractive index of the da layer on the ultrafine particle side, n _s
Is the refractive index of the layer formed of the ultrafine particles and the binder, n
Assuming that _G is the refractive index of the transparent plate, the reflectance Ra of the da layer can be expressed by the equation (Equation 1), and the refractive index Rb of the db layer can be expressed by the equation (Equation 2).

[0014]

(Equation 1)

[0015]

(Equation 2)

When the reflectance of a portion where no ultrafine particles are present is defined as Rc, the total reflectance R can be expressed by the following formula (Equation 3), where α is the area ratio of the portion where no ultrafine particles are present.

R = (1−α) (Ra + Rb) + αRc
(Equation 3) Rc is usually 4.2% when the same binder as that of the glass body is used.

Ra is n ₀ = 1.0, n ₁ = 1.10, n ₂ =
Assuming 1.38, n _s = 1.47, λ = 550 nm
Is about 0.19%. Further, Rb is about 0.04% at λ = 550 nm, assuming that n _G = 1.53 when the transparent plate is made of glass and other refractive indices are the same as those of Ra.

Accordingly, (Ra + Rb) << Rc, and it can be seen that the reflectance decreases as α decreases. In other words, when the ultrafine particles are applied regularly and densely, the reflectance becomes the smallest.

The present inventors have previously proposed applying ultrafine particles to an antireflection film, but as a result of further intensive studies,
By raising or lowering the coating solution on the substrate surface at a constant speed, the ultrafine particles mixed in the coating solution are regularly arranged and coated on the substrate, and a low reflectance close to the theoretical value is obtained.

In this case, it has been found that by using ultrafine particles having irregularities on the surface, diffuse reflection on the surface layer of the ultrafine particles is reduced, and a film free of white turbidity can be obtained. In this case, the antistatic ultrafine particles having a particle size of 1/10 or less of the particle size of the antireflective ultrafine particles are simultaneously mixed with the coating solution, so that the gap between the antireflective ultrafine particles is prevented from being charged. It has been found that the ultrafine particles for use are arranged in a network to form a conductive film.

An object of the present invention is to provide a charge and antireflection film which can be applied to a large area at a low cost and an image display panel using the same.

[0023]

Means for Solving the Problems The above object is achieved by making the surface of the antireflection function ultrafine particles porous .

The antireflection body of the present invention has at least the following modes.

(1) A film in which ultrafine particles having an antireflection function are dispersed is applied to a substrate, and the particle size of the ultrafine particles is set to 0.1.
1 to 0.15 [mu] m, and the surface portion is made porous with an opening diameter of 0.05 [mu] m or less .

(2) Ultrafine particles having an antistatic function are dispersed in the film together with the antireflection function ultrafine particles in the above (1).

(3) The substrate of (1) or (2) is a transparent plate.

(4) The ultrafine particles having a reflective function are SiO ₂ , M
selected from the group consisting of gF _2.

(5) When ultrafine particles having an antistatic function are used as in (2) above, SnO ₂ , SnO ₂ + Sb ₂ O ₃ , In
₂ O ₃ , In ₂ O ₃ + Sb ₂ O ₃

(6) In the above (1) to (5), if the substrate is glass, Si (OR) ₄ is used as a binder.

(7) In the above (1) to (5), when the substrate is a plastic, Si (OR) ₃ is used as a binder,
A coupling agent having a functional group for the plastic material is used in combination. If the plastic material is an acrylic resin, use γ-methacryloxypropyltrimethoxysilane as a coupling agent. If the plastic material is an epoxy resin, use γ-glycidoxypropyltrimethoxysilane.

(8) In the above (1) to (7), an ultrafine particle film is formed on both surfaces of the substrate, or an ultrafine particle film is formed only on one surface.

(9) Regarding the particle size of the ultrafine particles, the particle size D ₁ of the antistatic ultrafine particles is replaced by the particle size D _{2 of the} antireflection ultrafine particles.
And the ratio D ₁ / D ₂ is at least 1/10 or less, or the particle size of the antireflection ultrafine particles is 100 to 150 μm.
iO ₂ ultra-fine particles or antistatic ultra-fine particles
Ultrafine particles of a tin oxide compound having a particle diameter of 0 nm or less or having a particle diameter _two to three times as large as the particle diameter (D ₂ ) of the antireflection ultrafine particles are mixed at least 20 wt% or less of the total ultrafine particles.

(10) As a method of forming unevenness, each concave portion of the ultrafine particles preferably has an average diameter of 0.05 μm or less, and the unevenness is preferably evenly formed on the surface of the ultrafine particles.
The porosity is preferably about 50%. In this case, the diameter of the ultrafine particles is desirably not more than so-called micron (especially not more than 0.1 μm). The same applies to porous formation under these conditions. However, when several ultrafine particles are aggregated into fine particles, there are two types of fine particle formation methods.
In any case, it is preferable that the whole fine particles have an average diameter of 0.2 μm or less. One method is to provide smaller ultrafine particles around relatively large ultrafine particles (for example, having an average diameter of 0.15 μm or less), and the other method is to aggregate ultrafine particles having substantially the same diameter.

(11) In the above (1) to (10), the surface of the substrate on which the ultrafine particle film is formed has a curvature. Alternatively, it is selected from glass, ceramics, metal, and plastic, and has a plate shape or a film shape.

The transparent plate of the present invention has at least the following modes.

(12) An ultrafine particle film made of ultrafine particles and a binder filling each ultrafine particle gap is formed on a transparent substrate, and a coupling agent having a functional group for the substrate material is mixed between the ultrafine particles and / or Alternatively, it is present at the interface between the ultrafine particle film and the transparent substrate. The device having the function of preventing internal reflection of the ultrafine particles is devised in the above (1).

(13) In addition to the above (12), a coating solution mainly containing a silicic acid step is further applied on the ultrafine particle coating film.

(14) An ultrafine particle film composed of a group of ultrafine particles and a binder filling each ultrafine particle gap is formed on a transparent substrate, and a layer mainly composed of ethyl silicate is formed on the ultrafine particle coating film. The device having the function of preventing the internal reflection of the ultrafine particles is formed as described in (1) above.

(15) In the above (12) to (14), ultrafine particles having an antistatic function are used in combination. In this case, the ultrafine particles are S
nO ₂ , SnO ₂ + Sb ₂ O ₃ , In ₂ O ₃ , In ₂ O ₃ + Sb
It is desirable to use one selected from the group of ₂ O ₃ .

(16) In the above (12) to (15), the antireflection function ultrafine particles are selected from the group consisting of SiO ₂ and MgF ₂ , and the surface of the antireflection function ultrafine particles has irregularities or porosity or aggregates ultrafine particles. The fine particles are formed into fine particles to form a concave portion between the fine particles on the surface of the fine particles.

(17) In the above (12) to (16), when the substrate is glass, Si (OR) ₄ is used as a binder. Alternatively, when the substrate is plastic, Si (O
R) ₃ and a coupling agent having a functional group for the plastic material is used in combination. When the plastic material is an acrylic resin, γ-methacryloxypropyltrimethoxysilane is used as a coupling agent. When the plastic material is an epoxy resin, γ-glycidoxypropyltrimethoxysilane is used.

(18) In the above (12) to (17), an ultrafine particle film is formed on both surfaces or only one surface of the substrate.

(19) In the above (12) to (17), the above (9) and (10) are devised for the particle diameter.

(20) In the above (12) to (19), the substrate is devised in the above (11) for the substrate.

An application apparatus according to an application of the present invention is a device in which each of the above ultrafine particle films is formed on a surface of a substrate, particularly a transparent substrate, or each of the above transparent plates and an antireflection body is applied to the surface of a substrate such as a transparent substrate. An image display plate, an image display plate protection plate having the same configuration as that of the image display plate, a cathode ray tube having a plate-like body, another cathode ray tube, a liquid crystal display device, a window glass,
Protective bodies such as various panels and lenses.

The method for producing an antireflection body and a transparent plate according to the present invention is characterized in that an ultrafine particle film is formed on a transparent substrate by forming, for example, an ultrafine particle group and a binder which fills a gap between the ultrafine particles. It is preferable that a substrate to be placed is placed on a container, a mixed coating solution containing ultrafine particles and a binder is introduced into the container, and is raised or lowered on the substrate surface at a constant speed to form an ultrafine particle film on the substrate surface.

In a method for manufacturing a cathode ray tube, for example, the transparent substrate surface of the cathode ray tube is exposed in the container from an opening on the side of the container, a mixed coating solution containing ultrafine particles and a binder is introduced into the container, and the mixture is introduced at a constant speed. By raising or lowering the substrate surface to form an ultrafine particle film on the substrate surface.

[0049]

[Function] As described in (1) above, diffuse reflection can be reduced by each of the contrivances of unevenness, porosity, and ultrafine particle assembly. Diffuse reflection refers to reflection that diffuses in all directions in the reflection. According to the present invention, when the leading end of the optical path reaches the concave portion of the ultrafine particles, the light travels in the concave portion. In the diffuse reflection, a visually applied film becomes cloudy, the transmittance also deteriorates, and the resolution also decreases.

The diffuse reflectance is as low as possible while improving the resolution.
Want to be, but actually difficult. If the ultrafine particles are ultra-fine particles (average particle size of 0.01 μm or less), the diffuse reflectance becomes 0, but the regular reflectance approaches untreated. Therefore, as a measure to keep the diffuse reflectance close to 0 while maintaining the size of the ultrafine particles, unevenness (including,
Porous, ultra-fine particle assembly).

In general, when a film is formed by a dipping method using a coating solution containing no ultrafine particles,
It is known that the following equation (Equation 4) holds between the film thickness t and the pulling speed v.

T = K (ηv / pg) ⁰⁵ (Equation 4) where η is the viscosity of the solution, p is the density of the solution, g is the gravitational acceleration, and K is a constant.

On the other hand, the present inventors have found that, when the ultrafine particle mixed coating liquid is raised or lowered at a constant speed on the substrate surface, a film in which ultrafine particles are arranged in a single layer up to a certain pulling speed as shown in FIG. It was found that a film having a two-layer structure or a three-layer structure was formed above this.

Therefore, when ultrafine particles having a particle diameter of D ₂ are mixed as the ultrafine particles for the antireflection function, the apparent film thickness becomes D ₂ within the speed range of the single layer arrangement. The critical speed at this time is about 10 mm / s.

Further, it is very difficult to apply a film to a substrate having a complicated shape such as a cathode ray tube by a usual dipping method. The coating film can be easily formed by raising or lowering the coating solution at a constant speed in the bathtub.

When a film is formed from the mixed ultrafine particles, each ultrafine particle exerts its function. For example, if ultra-fine particles containing a large amount of components are used as the antireflection function component, the surface roughness is mainly effective, and the low reflection function is exhibited. Further, when the other small amount of ultrafine particles is a conductive functional component having a particle size of 1/10 or less of the particle size of the antireflection function ultrafine particles, conductivity is exerted by an effect of agglomerating in a network. In this way, a film having two properties for preventing reflection and charging can be obtained by a single application by the method of the present invention.

Further, when ultrafine particles having a particle diameter that is two to three times the particle diameter of the large amount of component ultrafine particles are added to the mixed coating liquid, the ultrafine particles are arranged in an island shape. In this state, it is as if these relatively large ultrafine particles are present in the sea of antireflection function ultrafine particles.

Since this interval is about 1-2 μm,
When this film receives mechanical frictional force, it comes into point contact with the large ultrafine particles and does not contact the antireflection function ultrafine particles, so that the optical characteristics do not change at all. In other words, the optical strength of the film against the frictional force is significantly improved. Further, for the same reason, the easiness of falling off of dirt such as oil is also improved.

Normally, when a human touches the uneven surface of the submicron order, a fingerprint is transferred to the film and does not easily fall off even after washing with alcohol or the like. By arranging them in a shape, it is difficult for the fingerprint to be transferred to the film, and at the same time, even if the fingerprint is transferred, it can be easily wiped off.

The anti-reflection film forming technique of the present invention uses a transparent plate,
It is needless to say that the present invention is not limited to an image display panel, a cathode ray tube, and the like, and can be applied to an opaque body, a metal body, a light absorber, and the like without departing from the gist of the present invention.

[0061]

Embodiments of the present invention will be described below with reference to the drawings. First, the components of the present invention will be described separately.

(Ultra-fine particles) The function of the ultra-fine particles is not particularly limited as long as the transparency and the light transmission are not hindered . Furthermore, typical features, antistatic, an antireflective and / or infrared reflecting.

The antistatic ultrafine particles are SnO ₂ (tin oxide), SnO ₂ + Sb ₂ O ₃ (antimony oxide), In ₂ O
₃ (indium oxide), is preferably selected from the group consisting of _{In 2 O 3 + Sb 2 O} 3. Antireflection ultrafine particles are SiO
₂ (silicon dioxide) and MgF ₂ (magnesium fluoride). The infrared reflective ultrafine particles are SnO ₂ , SnO ₂ + Sb ₂ O ₃ , In ₂ O ₃ , In ₂ O ₃
It is preferable to be selected from the group of + Sb ₂ O ₃ , TiO ₂ (titanium oxide), and ZrO ₂ (zirconium oxide).

The average particle size of the antireflection ultrafine particles is 10
0 to 150 nm is desirable. If the particle size of SiO ₂ or the like is smaller than 100 nm, the outermost surface of the formed film may be too flat to obtain a sufficient antireflection effect, while if the particle size is larger than 150 nm, the antireflection effect may be sufficiently obtained. However, this is because diffuse reflection becomes large, and as a result, there is a possibility that the resolution becomes lower at the same time as white turbidity. Therefore, the average particle diameter of the antireflection ultrafine particles is preferably 100 to 150 nm. In this case, also uneven have a surface as a porous
Noya, small ultrafine particles are provided on the surface of large ultrafine particles.
Though the use of those surfaces is one of the particles with irregularities, reduces the scattered light at the grain terminal surface can result film overall diffuse reflection also eliminate the white turbidity very small. As a method of providing irregularities on the surface of the ultrafine particles, there is a method of making the surface of the ultrafine particles porous as shown in FIG. In addition, the method of providing pseudo irregularities includes a method of providing small ultra-fine particles around relatively large ultra-fine particles (FIG. 8B) or a method of forming an aggregate of at least three or more relatively small ultra-fine particles. Either method may be used. Incidentally, the refractive index of each of the antireflection ultra-fine particle materials such as SiO ₂ and MgF ₂ is 1.50 or less.

The average particle size of the antistatic ultrafine particles is 10 nm.
The following is desirable. Further, two or more kinds of antistatic ultrafine particles may be used in combination. When used in combination with the antireflection ultrafine particles, the particle diameter of the antistatic ultrafine particles is preferably 1/10 or less of the particle size of the antireflection ultrafine particles. That is, when a solution in which two kinds of fine particles having different particle diameters are mixed is applied, the particles are relatively well dispersed when the particle diameter ratio is within 1/10.
This is because when the particle size is 10 or more, the fine particles having a small particle size without being dispersed are aggregated in a network.

From the above, if the particle diameter of the antistatic ultrafine particles is within 1/10 of the particle diameter of the antireflective ultrafine particles, the particles are sufficiently dispersed to the extent that the conductivity is lost, and as a result, the antistatic function is not exhibited. On the other hand, when the particle size ratio is 1/10 or more, the particles are aggregated in a network form, so that the film becomes a conductive film and exhibits an antistatic function well. In the case of the present invention, since the appropriate particle size of the antireflection ultrafine particles is 100 to 150 nm, the appropriate particle size of the antistatic ultrafine particles is preferably 10 nm or less.

The composition ratio of the antireflection ultrafine particles and the antistatic ultrafine particles is preferably 10% or more of the total ultrafine particles. This amount is 5
If it is 0% or more, the antireflection function may be deteriorated, and it is necessary to adjust it to 50% or less.

For the same reason, it is desirable to mix ultrafine particles having a particle diameter that is two to three times the particle diameter of the antireflection ultrafine particles at least not more than 20% by weight of the total ultrafine particles.

Ultrafine particles having an infrared reflecting function, an electromagnetic shielding function or a transparent conductive function include TiO ₂ ,
Examples include metal oxides such as ZrO ₂ , SnO ₂ , and In ₂ O _3, and mixtures thereof. Among them, SnO ₂ +
10% by weight Sb ₂ O ₃ or In ₂ O ₃ + 5% by weight Sn
O ₂ is preferable because it has excellent conductive properties and infrared reflection properties. The film thickness is 0.2 to 0.5 μm, and the particle size is 0.01 to 0.0.
5 μm is desirable.

Incidentally, the ultrafine particles of the present invention are composite granules composed of two or more inorganic oxides,
Whether two or more inorganic oxides are mixed with each other,
Alternatively, one of the inorganic oxides is included in the other inorganic oxide to form a granular structure, and the average particle size is 0.1 μm.
m or less. Preferably, the particle size distribution shows a maximum peak at particles having a particle size near the average particle size, and particles having that particle size account for approximately 50% of all particles.
Occupied above, the maximum particle diameter is almost twice as large as the average particle diameter, and the minimum particle diameter is about half that of the average particle diameter. Minor components (equivalent to solute) mixed in each ultrafine particle (equivalent to solvent)
Preferably has an average particle size of 0.01 to 0.05 μm.

The ultrafine particles are not limited to spherical shapes, but may be defective spheres. However, if the particle size of the ultrafine particles is too small, the outermost surface of the formed film may be too smooth and a sufficient antireflection effect may not be obtained, so the average particle size is preferably 0.05 μm or more. Conversely, if it is too large, the diffusion effect will be too large, and the resolution will be reduced and the film strength will be reduced. Therefore, it is desired that the average particle size be 0.1 μm or less. A typical combination example of the above two or more inorganic oxides is composed of a conductive component and an antireflection function component. Although the composition ratio of the conductive component and the antireflection function component varies somewhat depending on the manufacturing conditions, the conductive component is preferably at least 10% (by volume ratio of at least 0.1) of the total weight of the ultrafine particles. If the amount exceeds 50% or more, the antireflection function may be deteriorated, and it is necessary to adjust the amount to 50% or less. For convenience, the conductive component may be referred to as a small component, and the antireflection functional component may be referred to as a large component.

It is not clear whether each component constituting the ultrafine particles according to the present invention forms a granular material in a certain form depending on the type and performance of each component, but it is not clear whether a small amount May be included in the form of particulate matter in the major component, and in this case, the average particle size of the granular material formed by the minor component is preferably 0.01 to 0.05 μm.

The combination of each component is not limited to the combination between the above components, but it is essential that each of the ultrafine particles can fulfill two functions. When a small component is mixed with a large component as described above, if the ultrafine particles composed of the large component are compared with the sea, the small particles of the mixed small component exist as if they were islands. The ultrafine particles of the present invention contain a conductive component having an average particle diameter of 0.01 to 0.05 μm or fine particles comprising a conductive component and an antireflection functional component in a weight ratio of 10%.
The same effect as that obtained when only the ultrafine particles of the present invention is used can be obtained by adding the following.

A desirable particle size distribution is such that the maximum peak is near the average particle size, and the particle size is approximately 50% of the total particles.
The maximum particle diameter is about twice the average particle diameter, and the minimum particle diameter is about 1/2 of the average particle diameter.

The particle size (average particle size) of the ultrafine particles (particularly, SiO ₂ ultrafine particles) is restricted by the relationship between the resolution of the image and the effect of preventing reflection of external light. If the angle is smaller than 100 °, it is difficult to obtain the desired antireflection effect. On the other hand, the upper limit is determined from the viewpoint of the resolution. If the angle exceeds 10,000 °, the resolution is significantly reduced. Therefore, the above range is determined as a practical range, but preferably 50
0-1200 °, more preferably 500-600 °,
More preferably, it is about 550 °.

When ultrafine particles of SiO ₂ are used, even if the amount of fixing is small, a certain effect can be recognized, but practically it is 0.01 to 1 mg / cm ² per unit area of the substrate, and preferably 0.1 to 0.1 mg / cm ² . 1 to 0.3 mg / cm ² . The reason for the upper limit and the lower limit is that the lower limit is determined from the viewpoint of the antireflection effect and the upper limit is determined from the viewpoint of the resolution as in the case of the above-mentioned particle size.

When the conductive component (small component) and the antireflection function component (large component) are used in combination as the ultrafine particles, the composition ratio slightly varies depending on the production conditions, but the conductive component is 10% of the total weight of the ultrafine particles. Preferably, the volume ratio is 0.1 or more (volume ratio is 0.1 or more). If the amount exceeds 50% or more, the antireflection function may be deteriorated, and it is necessary to adjust the amount to 50% or less. When the antireflection film made of the ultrafine particles is used for an image display face plate, the conductive component is preferably transparent. This is because it does not interfere with the light path.

Although it is not clear whether each component constituting the ultrafine particles according to the present invention forms a granular material in a certain form depending on the type and performance of each component, it is not clear whether a small amount May be included in the form of granules in the major component, and in this case, the average particle size of the granular material formed by the minor component is desirably 0.01 to 0.05 μm.

Representative examples of the antireflection function component are SiO ₂ (silicon dioxide) and MgO (magnesium oxide). On the other hand, typical examples of the conductive component are SnO ₂ (tin oxide), In ₂ O
₃ (indium oxide), Sb ₂ O ₃ (antimony oxide) and the like. Incidentally, two or more conductive components may be used in combination. The combination of both components is not limited to the combination between the above-mentioned components, but it is essential that the two kinds of functions be satisfied by each ultrafine particle. When a small component is mixed with a large component as described above, if the ultrafine particles composed of the large component are compared with the sea, the small particles of the mixed small component exist as if they were islands. The ultrafine particles of the present invention can be prepared by adding a conductive component having an average particle diameter of 0.01 to 0.05 μm or fine particles comprising a conductive component and an antireflection functional component to the ultrafine particles of the present invention in a weight ratio of 10% or less. The same effect as in the case of using only is obtained.

The ultrafine particles used in the present invention can be usually produced using a metal component. Such a manufacturing apparatus uses an arc, plasma (induction plasma, arc plasma), laser, electron beam, gas, or the like as a heat source to evaporate both the antireflection functional component and the conductive component, and then rapidly cools the raw material component. An apparatus that can be produced as ultrafine particles in a form mixed with each other is exemplified.

In the method for producing ultrafine particles by arc used in the present invention, the gas atmosphere in the system is changed to an oxygen gas or a mixed gas atmosphere of oxygen gas and an inert gas (helium gas, argon gas, etc.). An arc is generated between the raw material and a discharge electrode obliquely or perpendicular to the raw material to generate oxide mixed ultrafine particles of the raw material.

More specifically, an apparatus for producing ultrafine particles using a laser described in US Pat. No. 4,619,691 and US Pat.
No. 0,718 and 4,732,369 are ultra-fine particle generators utilizing an arc.

In addition, it is of course possible to produce by a chemical method.

These devices may be operated in a conventional manner, and the ultrafine particles according to the present invention can be produced by using these devices without any difficulty.

The use of ultrafine particles in which at least two or more materials are mixed makes it possible to produce oxide-mixed ultrafine particles of the raw material. In this case, by mixing materials having substantially the same evaporation rate, the mixed raw material can be obtained. Can be produced.

[0086] When the raw material is a metal or a metal oxide, similar oxide ultrafine particles are produced. At this time, when the mixed metal materials are apt to be combined, compound ultrafine particles tend to be produced, and when the mixed metal materials are difficult to be combined, respective oxide ultrafine particles tend to be produced. Since the oxide having conductivity and the oxide having an antireflection function are not usually combined, ultrafine particles in which each oxide is mixed are generated.

(Substrate, Substrate) The material of the substrate and the substrate is not limited to glass, plastic, metal, and ceramics.
It may be in the form of a film or other three-dimensional shape, and the construction location may be flat or curved.

The light-transmitting substrate may be a glass plate or a plastic plate. The main components of the plastic plate include, for example, polyethylene, polypropylene, urethane, acrylic, phenol, epoxy, melamine, nylon, polyimide, polycarbonate, butyl, epoxy phenol, vinyl chloride, and polyester. The surface of the substrate on which the ultrafine particles are formed may have not only a flat plate shape but also a curvature like a cathode ray tube. The surface on which the ultrafine particles are formed may be one side or both sides.

(Ultrafine Particle Film) The film according to the present invention is mainly composed of the above ultrafine particles. In addition, the raw material component of the above-mentioned ultrafine particles is extremely small ultrafine particles (average particle diameter: 0.01 to 0.05 μm).
If so, a mixture of the ultrafine particles of the present invention and the ultrafine particles is also within the scope of the present invention.

Although one layer is sufficient, two layers may be used if desired. The thickness of this thin film is 0.1
It is preferably from 1 to 0.2 μm. The total film thickness of one layer, two layers or more is preferably 0.3 μm or less on average.

The optimum ratio between the conductive component and the antireflection function component in the thin film is the same as the optimum ratio described in the section of the ultrafine particles. The mixed ultrafine particles of the conductive component and the antireflection function component can be made into a thin film by coating an appropriate amount of the ultrafine particles on a substrate, and a further coating is ideal from the viewpoint of workability and economy. The valley formed between the ultrafine particles preferably has a depth of 0.05 to 0.2 μm. The distance between the conductive components of the contacting ultrafine particles is 0.05 μm.
The following is preferred.

The method for forming the thin film is Si (OR) ₄ (where,
The ultrafine particles of the present invention or the raw material ultrafine particles are dispersed in an alcohol solution in which R is an alkyl group), and this solution is coated on a translucent image display panel, and the coated surface is heated (fired). Thus, a film in which the ultrafine particle thin film obtained by hydrolyzing the Si (OR) ₄ is covered with SiO ₂ is formed.
Since SiO _{2, which} is a decomposition product of Si (OR) ₄ , enters the gap between the ultrafine particles and the substrate, it also serves as an adhesive.

In general, R of the above Si (OR) ₄ is preferably an alkyl group having 1 to 8 carbon atoms, particularly 5 alkyl groups. Also Si
The alcohol for dissolving (OR) ₄ increases the viscosity of the Si (OR) ₄ alcohol solution with an increase in the number of carbon atoms of R, so that the alcohol is appropriately adjusted so as not to become too high in consideration of workability. You just have to select Generally usable alcohols include alcohols having 1 to 5 carbon atoms.

Further, a salt of a metal belonging to Group II or III of the periodic table may be added to the thin film for imparting an antistatic effect. Representative examples include aluminum hydrochloride, nitrate, sulfate and carboxylate.

Further, water may be added to promote the hydrolysis of Si (OR) ₄ and a mineral acid such as nitric acid may be added as a solvent to adjust the thin film coating solution.

As a method of applying the above-mentioned alcohol solution onto the substrate, it is practical to use a coating method comprising a spinning method, a dipping method, a spray method or a combination thereof, and to heat the coated surface at 50 to 200 ° C. It is.

It is practical to further laminate a transparent conductive film on the antireflection film. In this case, the transparent conductive film serves as a base of the anti-reflection film, but its thickness is practically preferably 2,000 ° or less, more preferably 50 to 500 °, although it depends on the material constituting the film. It is. Typical examples of the transparent conductive film include SnO ₂ and In ₂ O _3.
And Sb ₂ O is ₃ at least those of a conductive metal oxide film made of a kind, other, SiO ₂ thin film of at least one metal salt having these transparent conductive metal oxides and hygroscopic It may be a thin film provided with conductivity by being contained therein.

The metal salt having hygroscopicity contained in the SiO ₂ thin film may be an inorganic acid salt such as hydrochloride, nitrate or sulfate, or an organic acid salt such as carabonate. Preferred examples of these metal salts include salts of a metal element of Group II represented by magnesium and salts of a metal element of Group III represented by aluminum. These metal salts reduce the electric resistance of the panel surface by absorbing atmospheric moisture.

On the other hand, a conductive metal oxide is more preferable than a metal salt in order to reduce the electric resistance of the panel surface because it has conductivity itself. And S
iO amount of the metal oxide and metal salts to impart these conductive contained in ₂ thin film is moderate effect even in a small amount is observed per unit area of the SiO ₂ thin film 0.01-1.
0 mg / cm ² is preferred, more preferably 0.15 to 0.1 mg / cm ² .
3 mg / cm ² . That is, the lower limit of this numerical value is limited by the effect of decreasing the conductivity, and the upper limit is limited by the strength of adhesion to the panel surface.

The underlying conductive film must have a film thickness and characteristics that hardly affect the performance of the antireflection film formed thereon. Satisfies these conditions.

The step of forming the transparent conductive film will be described in detail. Due to the formation on the cathode ray tube panel (image display face plate), it is desirable to form the glass plate constituting the panel at a temperature that does not cause distortion (about 500 ° C. or less). Any one may be used. Hereinafter, a typical method for forming a transparent conductive film will be described.

I) The method of directly forming a conductive metal oxide composed of at least one of SnO ₂ , In ₂ O ₃ and Sb ₂ O _{3 on} a glass panel is as follows. (1) Each metal oxide is used as a target. A method in which a metal oxide film is formed on a panel surface by sputtering in a device facing a panel surface in a sputtering apparatus, and (1) a method of forming a metal oxide film on a panel surface by a known CVD method using an organometallic compound as a raw material. There is. As the organometallic compound in the case of the above (2), for example, when tin, indium or antimony is represented by M, its valence is represented by m, and the alkyl group is represented by R (where R = CnH _{2n + 1} , Is n = 1 ~
5), an alkyl metal compound M (R) _m or an alkoxy metal compound M (OR) _m . Specific examples include Sn (CH ₃ ) ₄ and Sn (OC ₂ H ₅ ) ₄ .

Ii) Next, a method of forming a transparent conductive film by adding a conductive substance to the SiO ₂ thin film will be specifically described.

The thin film of SiO ₂ is made of alkoxysilane Si
(OR) ₄ (where R is an alkyl group, and practically n =
It can be easily obtained by hydrolyzing 1) to 5). In the present invention, the transparent conductive metal oxide and the moisture absorbing agent described in detail in the invention of the cathode ray tube for achieving the first object for imparting conductivity to the alcohol solution of Si (OR) ₄ are provided. At least one additive of a metal liquid having a property is added, the solution is applied to the panel surface, and the applied surface is heated to decompose Si (OR) ₄ to form a SiO ₂ thin film. is there. Practically, the amount of the additive is preferably 0.05 to 7% by weight based on the alcohol solution.
More preferably, it is 1.0 to 2.0 wt%.

Among the additives, the transparent conductive metal oxide does not dissolve in the alcohol solution but merely disperses. In the case of the metal salt, a part or the whole dissolves. In order to form a SiO ₂ thin film having good conductivity, it is desirable to disperse or dissolve this additive in the above alcohol solution. From this point, ketones such as acetylacetone or the like as a dispersing medium in the above solution are further used. Add ethyl cellosolve and add Si
It is more preferable to add water and an inorganic acid such as nitric acid as a catalyst to facilitate the hydrolysis of (OR) ₄ .

The alcohol solvent for dissolving the Si (OR) ₄ is desirably an alcohol constituting the alkyl group R.
The most practical example is a case where R is tetraethoxysilane Si (OC ₂ H ₅ ) ₄ composed of n = 2 ethyl groups and the solvent is ethyl alcohol.

As a method for applying the above-mentioned alcohol solution to the panel, a coating method comprising a spinning method, a dipping method, a spray method or a combination thereof is used.

The heating conditions for heating the coated surface to decompose Si (OR) ₄ to form a SiO ₂ thin film are preferably 50 to 200 ° C., and more preferably 160 to 200 ° C.
１８０180 ° C. This method of forming a conductive SiO ₂ thin film is more advantageous than the above-mentioned method i) because it is processed at a relatively low temperature in this manner. Therefore, it is suitable for a mass production process. Also, it goes without saying that it can be processed in the process of manufacturing a CRT before it is completed as a sphere.

In the method for obtaining an antireflection film by providing irregularities on the glass surface, the size of the irregularities is 0.1 μm.
It is desirable that the volume continuously changes in the depth direction at about m 2. Thereby, the refractive index changes continuously, and an antireflection effect is obtained. In this case, when ultrafine particles of SiO ₂ having a uniform particle size without a particle size distribution are used, they adhere neatly, so that a film whose volume continuously changes in the depth direction cannot be obtained. Is very little.

However, when ultrafine particles having a particle size distribution are used, appropriate pores can be provided, and as a result, the volume continuously increases in the depth direction, and an antireflection effect is obtained. Rara. Also by using a Si (OR) ₄ alcohol solution as a solution, 0.99 ° C. and forth Si (OR) ₄ alcohol solution sublimed object value other than Si in and Si precipitates form a layer of glass and SiO ₂ than This has the effect of firmly adhering the fine particles. Si whereas Si (OR) ₄ acetylacetone to mix the alcoholic solution, acetone, ethyl alcohol for diluting the Si (OR) ₄ alcohol solution, precipitated
This has the effect of controlling the film thickness.

The present invention can naturally be applied to ordinary chemical ultrafine particle production methods. In this case, however, the particles become uniform. Therefore, in order to positively impart a particle size distribution, a physical method such as an arc method is used. It is effective to devise so as to obtain ultrafine particles by a technical method. In addition, conductive particles (InO
₂ , SnO ₂ etc.) and anti-reflective particles (SiO ₂ etc.) are effective, but not a mixture of particles having different characteristics, but particles having both characteristics for each particle. If it is obtained (for example, Si-In-O-based particles), the conductivity does not decrease, and the antireflection is effectively achieved.

Next, the step of forming an antireflection film on the transparent conductive film as a base will be described in detail.

First, a method of dissolving and preparing alkoxysilane Si (OR) ₄ in alcohol will be described. All of Si (OR) _{4 as} a raw material and alcohol as a solvent form a base of the above-mentioned transparent conductive film. Ii. ))
Since it is the same as the method of forming the O ₂ thin film, a detailed description is omitted.

In the same manner as in ii) above, an alcohol solution containing Si (OR) ₄ was added to an alcohol solution having a particle size of 100 to 10,000 °.
_{(2) The} fine particles are dispersed, and the amount of dispersion is practically 0.1 to 10 from the viewpoint of the antireflection effect and the resolution of the image.
wt% is preferred, and more preferably 1-3 wt%. In order to improve the dispersibility of the SiO ₂ fine particles and the hydrolyzability of Si (OR) ₄ , a ketone such as acetylacetone or ethyl cellosolve is further added as a dispersion medium to the above solution, and the hydrolysis is facilitated. It is more preferable to add an inorganic acid such as nitric acid as water and a catalyst for this purpose.

The above-mentioned Si (OR) ₄ is hydrolyzed to form Si (OR) _4.
It forms a thin film of O ₂ and serves to fix the SiO ₂ fine particles to the panel surface. When the alkyl group R is represented by the general formula CnH _{2n + 1} , the practical n is 1 to 5. And preferably n = 2 ethyl groups. The alcohol of the solvent for dissolving the Si (OR) ₄ is desirably an alcohol of an alkyl group R. As the most practical example, R of the alkoxysilane Si (OR) ₄ is an ethyl group of n = 2, Is the case of ethyl alcohol.

Further, the Si in which the SiO ₂ fine particles are dispersed is used.
(OR) ₄ in an alcohol solution as a method of coating on a panel formed of the underlying transparent conductive film, as in the case of ii) above terms in said electrically conductive thin SiO ₂ film formation, spinning, dipping, A spraying method or a coating method comprising a combination thereof is used.

Further, the coating surface is heated to
(OR) ₄ is decomposed to form a SiO ₂ thin film, and the dispersed S
The heat treatment conditions for coating and fixing the iO ₂ fine particles with this SiO ₂ thin film are preferably 50 to 200 ° C,
The temperature is more preferably 160 to 180 ° C.

A thin film as an anti-reflection film material is formed by each of the above methods. However, since the heat treatment temperature can be formed at a relatively low temperature in the same manner as the above-mentioned method of forming the base film ii), it is particularly completed. It is convenient to form it on the panel surface of a cathode ray tube.

As described above, the surface of the antireflection film may be fine (submicron order), but in the case of particles of uniform size such as ultrafine particles by a chemical manufacturing method, it is difficult to form such an uneven surface. . Therefore, the inventor of the present invention has decided to perform an etching process after forming a thin film in order to surely provide fine irregularities on the surface.

In this case, if a binder having an etching rate higher than that of the ultrafine particles is used, the binder will be more gradually removed from the surface by etching than the ultrafine particles in the etching solution. As a result, an ultrafine particle film having irregularities on the order of microns can be obtained. The etchant is an aqueous solution of sodium hydroxide or an aqueous solution of hydrogen fluoride, depending on various etching conditions. However, sodium hydroxide (for example, a 5% aqueous solution) is preferable because hydrogen fluoride easily removes even ultra-fine particles such as SiO _{2 in a} short time and makes process management difficult. Even if SiO ₂ is contained in a binder calcination decomposition product using an aqueous solution of sodium hydroxide, the binder is dissolved and removed more aggressively than SiO ₂ ultrafine particles.

Since the reflection of light occurs at the interface where the refractive index changes abruptly, if the refractive index changes gradually at the interface, no reflection occurs. Usually, soda glass (refractive index about 1.5
For the anti-reflection of 3), the material having the lowest reflectance, magnesium fluoride (MgF ₂ ) (refractive index: about 1.38), is deposited by sputtering or the like, but the interface between the glass substrate and the MgF ₂ film, MgF ₂ Since the refractive index changes suddenly at the interface between the film and air (refractive index: about 1.0), the antireflection effect is not sufficient. Therefore, if a film whose refractive index gradually changes from a refractive index close to a glass substrate to a refractive index close to air can be formed, an effective antireflection effect can be obtained.

Therefore, a substance having a refractive index intermediate between that of the glass substrate and MgF ₂ , for example, ultrafine particles of SiO ₂ (refractive index: 1.46) and ultrafine particles of MgF ₂ are mixed, applied to the glass substrate, and mixed. varying the ratio in the thickness direction, i.e. gradually from the glass substrate surface toward the coating film surface to reduce the mixing ratio of SiO ₂ ultrafine particles, by increasing the mixing ratio of MgF ₂ ultrafine particles, the coated surface and the glass substrate The change in the refractive index at the interface becomes more gradual, and an effective antireflection effect can be achieved.
Further, according to the present method, a large-area antireflection film can be formed at low cost.

A substance having a refractive index close to a glass substrate (eg, SiO ₂ ) and a substance having a refractive index close to air (eg, Mg)
By using ultrafine particles when mixing with F ₂ ), both substances can be uniformly mixed at a level smaller than the wavelength of light. Therefore, the refractive index becomes an average refractive index corresponding to the volume fraction of SiO ₂ and MgF ₂ . That is,
In ultrafine particle film of a mixture of SiO ₂ ultrafine particles and MgF ₂ ultrafine particles, an average refractive index n (x) at the position in the thickness direction X is the volume fraction of SiO ₂ ultrafine particles in the same position V (s ), N (x) = 1.46 × V (s) +1.3
8 × {1-V (s)}. Therefore, if the mixing ratio is changed in the film thickness direction, the refractive index changes correspondingly, and the change in the refractive index at the interface between the glass substrate and the coating film becomes gentle.

Further, by stacking coating films having different mixing ratios, it is possible to form a film whose average refractive index gradually changes as a whole.

The solution is a mixture of an alcohol solution of Si (OR) ₄ (R is an alkyl group, preferably having 8 or less carbon atoms, for example, C ₂ H ₅ —) and at least two of acetylacetone and acetone ethyl alcohol. Is preferred.

It should be noted that if the average particle size exceeds 0.3 μm, light interference will cause visual impairment.

In the method of forming an antireflection film on a glass surface, a solvent containing ultrafine particles having an average particle size of 0.1 μm or less is coated on the glass surface, baked, and then coated with Si (OR) It is preferable to overcoat an alcohol solution of ₄ (R is an alkyl group) and a mixture of at least two or more of acetylacetone and acetone ethyl alcohol. Incidentally, such an antireflection film is particularly suitable for an image display tube.

(Additives) The additives are added, for example, for antistatic purposes, and the metal salt particles are selected from those having a hygroscopic property.
It is a salt of a metal element selected from at least one of Group III and Group III, and is practically a hydrochloride, a nitrate, a sulfate, and a carboxylate, and at least one of these salts is selected. Particularly preferred are at least one of the above salts of magnesium and aluminum.

The above-mentioned metal salts reduce the electric resistance of the substrate surface by absorbing moisture in the atmosphere. On the other hand, since the conductive metal oxide particles have conductivity themselves, they are more preferable than the above-mentioned metal salts for reducing the resistance of the substrate surface. Practical ones of this kind of metal oxide particles are at least one oxide of tin, indium and alimon, all of which are oxides constituting a transparent conductive film. However, it goes without saying that other well-known conductive metal oxides, for example, those having a perovskite structure may be used. Although a certain effect can be recognized even if the practical fixing amount of such an additive is small, it is 0.01 to 1.0 per unit area of the substrate.
0 mg / cm ² is preferred, more preferably 0.15 to 0.1 mg / cm ² .
3 mg / cm ² . That is, the lower limit is restricted by the effect of reducing the conductivity of the substrate surface, and the upper limit is restricted by the adhesion strength to the substrate surface. That is, as the fixing amount increases, the resistance value decreases, but the adhesion strength decreases.

(Pretreatment) In consideration of wettability with the substrate, pretreatment such as alkali treatment or fluorine treatment is preferable.

(Coating Method) The rising or falling speed of the coating solution is preferably 10 mm / s or less. The substrate may be leaned against the inside of the container, or alternatively, the surface of the substrate may be exposed through a hole formed in the side surface of the container. The latter method is particularly suitable for forming an ultrafine particle film on an almost finished product such as a cathode ray tube.

The heat treatment of the coating surface is performed in an oven at 50 to 2 hours.
Although it is practical to bake at 00 ° C., baking may be performed in a short time by ultraviolet rays using a high-pressure mercury lamp or the like.

The above description has been made with reference to an example of the dipping method. However, as long as the method of coating a plastic substrate or the uniformity of the film surface is not limited, the dipping method is not limited to this dipping method, and other methods such as spinning, spraying, and spraying may be used. And combinations of these with the dipping method are also effective.

It is also effective to apply a coating solution containing ethyl silicate as a main component on the thickness of the ultrafine particles.

The number of layers may be one or two or more if necessary.

(Coating Solution) For forming the ultrafine particle film of the present invention, a coating solution obtained by adding a binder, a coupling agent and other additives as necessary to predetermined ultrafine particles is used.

When the translucent plate is a glass body, it is preferable to use Si (OR) ₄ (where R is an alkyl group) as a binder, and when the translucent plate is plastic, Si (OR) _X as a binder. (X = 2 to 4, particularly preferably 3) is preferably used. Further, when the translucent plate is made of plastic, it is desirable to use a coupling agent having a functional group for this plastic material.

When the translucent plate is a glass body, Si (OR)
_{4 When} the translucent plate is made of plastic, a functional group that easily reacts with this polymer and Si (OR) _x (X = 2 to 4, especially Preferably, ultrafine particles are dispersed in a silane coupling agent containing 3) or an alcohol solution in which a mixed solution of the above Si (OR) ₄ and the silane coupling agent is dissolved.

After this solution is applied on a light-transmitting plate by the above method, the applied surface is heated (or fired) to form a film. By this heat treatment, the 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, respectively.

In general, R of Si (OR) ₄ has 1 carbon atom.
~ 5 alkyl groups are preferred. On the other hand, the silane coupling agent needs to be appropriately selected depending on the polymer material of the light-transmitting 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, melamine, nylon, polyimide and polycarbonate, silane coupling agents such as γ-aminopropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane are effective. Further, in the case of butyl, epoxyphenol, vinyl chloride, and polyester, a silane coupling agent such as β, 3,4-epoxycyclohexylethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane is effective.

The alcohol for dissolving Si (OR) ₄ or the silane coupling agent becomes too viscous in consideration of workability because the viscosity of the mixed alcoholic solution increases with the increase in the carbon number of R. Alcohol may be appropriately selected so as not to occur. Generally usable alcohols include alcohols having 1 to 5 carbon atoms.

Further, a salt of a metal of Group II or III of the periodic table may be added to the above-mentioned film in order to impart an antistatic effect. Representative examples include hydrochloride, nitrate, sulfate and carboxylate of aluminum.

Further, in order to decompose Si (OR) ₄ , a coating solution may be prepared by adding water and a mineral acid such as nitric acid as a catalyst.

Hereinafter, an example in which the present invention is applied to the surface of a front panel of a CRT (glass face plate) will be described.

FIG. 1 shows an example of the apparatus of the present invention. In FIG. 1, 11 is a cathode ray tube, 12 is a coating bath, 13 is a coating solution, 14 is a pressure adjusting valve, 15 is an overflow valve, 16 is a solution tank, 17 is a solution supply pressurizing valve, and 18 is a leak valve. It is.

In such a configuration, the coating bath 12 was attached to the cathode ray tube 11. In this case, the mounting surface of the coating bath 12 is provided with a packing or an O-ring so that the coating solution and the pressurized gas do not leak during the coating process, and can be sealed only by inserting a CRT in consideration of workability. It has become.

Next, the coating solution containing the ultrafine particles was introduced into a space formed between the coating bath 12 and the surface of the cathode ray tube. For the introduction of the coating liquid, the overflow valve 15 and the solution supply pressure valve 17 were first opened.

With this operation, the coating solution 13 filled in the solution tank 16 was pressurized and filled on the surface of the cathode ray tube, and a part of the solution was put into the spare tank from the overflow valve 15. As a result, dust and the like adhering on the surface of the cathode ray tube or on the path could be discharged to the spare tank together with the overflowed solution.

Next, after closing the overblow valve 15 and the solution supply pressure valve 17, the pressure control valve 1 is closed.
When the valve 4 and the leak valve 18 were opened, the coating solution 13 filling the surface of the cathode ray tube was returned to the solution tank 16. In this case, the coating solution 1 is controlled by the gas pressure applied to the pressure adjusting valve 14 and the degree of opening and closing of the leak valve 18.
It was possible to adjust the speed at which the sample No. 3 descended on the surface of the cathode ray tube at a constant speed.

Next, a method of mixing the coating solution will be described.

First, ethyl silicate [Si (OC
₂ H ₅ ) ₄ ] was dissolved in ethanol, and a solution was prepared by adding H ₂ O for hydrolysis and HNO ₃ as a catalyst.
₍₂₎ 10% by weight of ultrafine particles and SnO ₂ having a particle size of 6 nm
2% by weight of ultrafine particles are added. At this time, the pH of the solution is adjusted so as to be sufficiently dispersed.

Next, the surface of the cathode ray tube was filled with this solution by the above method, and the coating solution was dropped at a speed of 1.0 mm / s to perform coating. Thereafter, the mixture was calcined at 150 ° C. for 30 minutes in the air to decompose ethyl silicate [Si (OC ₂ H ₅ ) ₄ ]. The SiO ₂ ultrafine particles added to the solution are firmly adhered to each other and simultaneously firmly adhered and fixed to the surface of the cathode ray tube, since the SiO ₂ formed by decomposition serves as a binder. By this method, uniform continuous irregularities due to ultrafine particles could be formed on the surface of the cathode ray tube.

Light was incident on the surface of the CRT on which this film was formed at an incident angle of 5 °, and the reflectance was measured. As a result, a low reflectance of 0.08% was obtained at a wavelength of 550 nm as shown in FIG. In this case, no cloudiness when viewed from a direction inclined with respect to the incident light, that is, no tindal phenomenon was observed.

On the other hand, the surface resistance of this film was measured to be about 10 ⁶ Ω / □. The charging characteristic is as shown in FIG. 3, which is almost the same as the conventional characteristic shown for reference. Turned out not to.

Next, as a result of rubbing the antistatic low-reflection film of the embodiment of the present invention 20 times with a load of 1 kg using an eraser (Lion Corporation, 50-30 type), the reflectance changed by about 0.1%. There was no problem in film quality at all.

Further, ultrafine particles having a particle size of 300 nm were mixed with the above solution at 10 wt% of the total ultrafine particle content, and the mixture was applied by the same method. As a result, the antireflection and antistatic effects were not changed at all, but the eraser test was performed. The change in reflectance before and after was 0.02%, and a film resistant to mechanical abrasion was obtained. This is because large ultrafine particles dispersed like islands in the film function as a barrier.

In the process of forming such a charging and anti-reflection film, a film can be formed directly on the completed cathode ray tube, and an S (OR) ₄ alcohol solution can be added to an existing Si (OR) ₄ alcohol solution.
iO ₂ ultra-fine particles and SnO ₂ ultra-fine particles are mixed and applied,
It is only necessary to bake, there is no use of harmful chemicals such as hydrofluoric acid, and it can be manufactured with constant quality and at low cost.

Further, in the above-mentioned embodiment, the example where R is an ethyl group as Si (OR) ₄ is shown, but as described above, R = C _n H _m
When (m−2n + 1), it can be carried out in the range of n = 1 to 5. When n becomes large, the viscosity of the solution becomes slightly high. do it.

As described above, according to this embodiment, an image display plate having a film having excellent antireflection effect and having an antistatic function can be formed in a single coating step.
Moreover, this face plate of the present invention can be manufactured by a simple and safe process without using harmful treatment chemicals such as hydrofluoric acid, is suitable for mass production, and has excellent stain resistance.

Another embodiment will be described with reference to FIG.

FIG. 7 shows an example of the apparatus of the present invention. In FIG. 7, reference numeral 51 denotes a transparent substrate, a plurality of which are placed on the jig 52 and placed in the coating bath 12. The transparent substrate of the cathode ray tube of the first embodiment is a glass plate, whereas the transparent substrate 51 is a plastic plate.

In this case, a packing or an O-ring is provided on the mounting surface of the coating bath 12 so that the coating liquid and the pressurized gas do not leak during the coating process.

Next, the coating solution containing the ultrafine particles was introduced into the space of the coating bath 12. The introduction of the coating solution is performed by firstly using the overflow valve 15 and the solution supply pressurizing valve 1.
7 was opened. By this operation, the coating solution 13 filled in the solution tank 16 was pressurized and filled in the coating bath 12, and a part thereof was put into the spare tank from the overflow valve 15.

Next, after the overflow valve 15 and the solution supply pressure valve 17 are closed, the pressure control valve 1 is closed.
When the valve 4 and the leak valve 18 were opened, the coating solution 13 filled in the coating bath 12 was returned to the solution tank 16. In this case, the coating solution 1 is controlled by the gas pressure applied to the pressure adjusting valve 14 and the degree of opening and closing of the leak valve 18.
3 was able to adjust the speed at which the lower surface of each of the plurality of transparent substrates 51 was lowered at a constant speed.

Next, a method of mixing the coating solution will be described.

First, ethyl silicate containing γ-methacryloxypropyltrimethoxysilane [Si (OC
₂ H ₅ ) ₃ ] was dissolved in ethanol, and a solution was prepared by adding H ₂ O for hydrolysis and HNO ₃ as a catalyst.
₍₂₎ 10% by weight of ultrafine particles and SnO ₂ having a particle size of 6 nm
2% by weight of ultrafine particles were added, and the pH of the solution was adjusted so as to be sufficiently dispersed.

Next, this solution was applied to the coating bath 1 by the above method.
2, and the coating liquid was dropped at a speed of 1.0 mm / s to perform coating. Thereafter, the mixture was calcined at 150 ° C. for 30 minutes in the air to decompose ethyl silicate. S added to the solution
The iO ₂ ultrafine particles are firmly adhered to each other and simultaneously firmly adhered and fixed to the surface of the cathode ray tube, because SiO ₂ formed by decomposition serves as a binder. By this method, uniform continuous irregularities due to ultrafine particles could be formed on the surface of the cathode ray tube.

(Ultrafine Particle Film Utilizing Apparatus) The apparatus in which the thin film according to the present invention exhibits the most effect is an image display surface or an antireflection film formed on a translucent substrate such as the above-mentioned thin glass substrate. This is a cathode ray tube incorporating a display panel.

The amount of the ultra-fine particles according to the present invention fixed to the substrate (especially when SiO ₂ is used as the anti-reflection function component) is 0.1%.
It is preferably from 0.1 to 1 mg / cm ² , more preferably from 0.1 to 1 mg / cm ^2.
0.3 mg / cm ² .

In the case of the above-mentioned utilization device, it is desirable that the conductive component is transparent. This is because it does not interfere with the light path.

(Others) When a thin film is formed by using two types of composite ultrafine particles, the function of the minor component continues to be used as the function of the main (large component) ultrafine particle. The function of the remaining ultrafine particles (mixed components) is exhibited by the tunnel effect because there is a distance between the ultrafine particles when focusing on adjacent ultrafine particles, but because of the extremely short distance that does not exceed the size of the ultrafine particles You.

In this case, the function of a component formed from a small amount of components and mixed in the form of ultrafine particles in ultrafine particles is such that although there is a distance between each ultrafine particle present in adjacent ultrafine particles, Because of the extremely short distance that does not exceed the size of
The tunnel effect is exhibited in terms of conductivity. In this case, the major component necessarily achieves a low reflection function due to its surface roughness, which is necessarily formed from its viscosity. The conductive component exhibits conductivity by a tunnel effect. Therefore, the film strength is improved by reducing the number of peeled portions as compared with the laminate of each functional component. In addition, since the tunnel effect can be utilized as compared with the case where ultrafine particles are produced and mixed for each functional component, the connection of both functions can be improved.

When the main ultrafine particles are used as the antireflection function component, the surface roughness is mainly effective to achieve the low reflection function. The conductive component exhibits conductivity by a tunnel effect. Therefore, the film strength is improved by reducing the number of peeled portions (potentials) as compared with the laminate of each functional component. In addition, since the tunnel effect can be used as compared with the case where ultrafine particles are produced and mixed for each functional component, both functions can be maintained.

An arc is generated between the ultrafine particle raw material and the discharge electrode by setting the gas atmosphere in the system to an oxygen gas or a mixed gas atmosphere of oxygen gas and an inert gas, and the arc heat generates vapor from the ultrafine particle raw material. As a result, oxide ultrafine particles reacted with oxygen in the activated atmosphere gas are generated.

At this time, by using an ultrafine particle raw material in which at least two or more materials are mixed, it is possible to produce an oxide mixed ultrafine particle as a raw material. In this case, by mixing materials having substantially the same evaporation rate, it is possible to generate oxide-mixed ultrafine particles having a composition ratio close to the mixed raw material.

[0177] Regarding the raw material as well, the same kind of ultrafine oxide particles can be produced regardless of whether the material is a metal or a metal oxide. At this time, when the mixed materials are apt to be combined, compound ultrafine particles tend to be generated, and when the mixed materials are difficult to be compounded, respective oxide ultrafine particles tend to be generated. Among them, the oxide having conductivity and the oxide having an antireflection function may not be combined, and in that case, ultrafine particles in which each oxide is mixed are generated.

When the oxide-mixed ultrafine particles are applied to the surface of glass or a display tube to form a film, a film having two characteristics of conductivity and antireflection function can be obtained. This film is preferably subjected to, for example, an etching treatment to form fine irregularities on the surface.

In this way, it is possible to form a single layer of the conductive anti-reflection film on the surface of the display tube at a low temperature.

As another method, in the case of a single anti-reflection function film (meaning no conductive film and no mixed conductive particles),
A thin film of SiO ₂ formed by hydrolysis of (OR) ₄ coats the uniformly dispersed SiO ₂ fine particles and fixes this to the surface of the glass body (substrate). This film is subjected to the etching treatment as described above. The uniformly dispersed SiO ₂ fine particles maintain the antireflection effect and the high resolution of the displayed image. Further, the SiO ₂ thin film contains an additive, that is, at least one of a metal salt having hygroscopicity and a conductive metal oxide. The former is a heat treatment at the time of hydrolysis of Si (OR) ₄ (this heat treatment is This also has the effect of reducing the resistance value of the substrate surface without losing its performance even after passing through.

The functions of the conductive treatment are as follows. That is, the conductive metal oxide exhibits a decrease in surface resistance based on the same principle as a so-called transparent conductive film, and the antistatic function is maintained due to the small surface resistance.
As described above, the additive of the present invention exhibits an antistatic effect, but the conductive metal oxide is superior to the metal salt in terms of lowering the surface resistance of the substrate. Especially in the case of oxides such as tin, indium and antimony,
It is also preferable in that the transparency of the film is good and the resolution of the image can be kept high. Some metal salts, unlike oxides, are fixed in the film in a dissolved state, and in such a case, the film has good transparency and has an effect of maintaining high resolution.

When the conductive film is used as the base film, the following functions are exhibited.

The base transparent conductive film has an effect of reducing the electric resistance of the panel surface by being in close contact with the panel surface. A film composed of a metal oxide having conductivity itself or a film in which a conductive metal oxide is dispersed in a SiO ₂ thin film has a decrease in surface resistance based on the same principle as a so-called transparent conductive film. Thereby, the antistatic function is maintained.

On the other hand, in the case of a film in which a metal salt having hygroscopicity is contained in the SiO ₂ thin film, the metal salt absorbs and retains water to provide conductivity.
Even after heat treatment during hydrolysis of i (OR) ₄ (this heat treatment also improves the film strength), hygroscopicity is maintained,
It has the effect of reducing the resistance value of the panel surface without losing its performance.

As for the additive contained in the SiO ₂ thin film, the conductive metal oxide is superior to the metal salt in terms of lowering the resistance value of the panel surface. In particular, oxides such as tin, indium, and antimony are preferable in that the film has good transparency and can maintain high image resolution. Some metal salts, unlike oxides, are fixed in the film in a dissolved state, and in such a case, the film has good transparency and has an effect of maintaining high resolution.

The reason why the front panel surface (image display surface plate) of a cathode ray tube such as a cathode ray tube is charged is that a thin and uniform aluminum film 4 is deposited on a phosphor applied on the inner surface of the cathode ray tube. When a high voltage is applied to the aluminum film, a charging phenomenon is caused by electrostatic induction on the front panel of the cathode ray tube when the voltage is applied and cut off.

Ultrafine particles (mainly those having an antireflection function such as SiO ₂ ) were dispersed in an alcohol solution in which Si (OR) ₄ (where R is an alkyl group) was dissolved, and this solution was applied on a substrate. Then, the coated surface is heated (fired) to obtain Si
(OR) ₄ is decomposed to form a film in which the ultrafine particle film is covered with SiO ₂ . SiO _{2, which} is a decomposition product of Si (OR) ₄ , enters the gaps between the ultrafine particles and the gap between the ultrafine particles and the substrate to serve as an adhesive.

When the thin film formed by the above method is etched for a very short time (several seconds to several tens of seconds) by a dry or wet method, SiO _{2 as} a binder decomposition product on the film surface is etched.
The rich layer is etched, and minute etching grooves are formed between the ultrafine particles. Thus, minute irregularities at the level of ultrafine particles are formed on the entire surface of the film, and exhibit an antireflection function.

If a spin coating method, a dipping method, or a spray method is used as a method of applying the above-mentioned alcohol solution on a substrate, a large-area treatment can be easily performed at a low cost. Further, the etching after firing is also performed with NaOH
When the method of immersion in an aqueous solution is used, large-area treatment is easy and the cost is low. Therefore, since the film is formed by the ultrafine particles, minute irregularities are generated on the surface of the coating film, and there is a further antireflection effect. Furthermore, since an antireflection film is formed by a coating method, an expensive vacuum evaporation apparatus is not required, and the area can be easily increased, and the cost can be reduced.

Since reflection of light occurs at the interface where the refractive index changes abruptly, if the refractive index changes gradually at the interface, no reflection occurs. A film having a refractive index distribution in the film thickness direction based on the above principle is the above-mentioned heterogeneous film.

If the substrate has irregularities smaller than the wavelength of light on the substrate, the individual irregularities cannot be regarded as interfaces, but can be regarded as surfaces having an average refractive index corresponding to the volume fraction of the substrate and air. That is, the average refractive index n _{x at} the position of the depth x in the film thickness direction
Is the volume fraction occupied by the substrate, v ( _x ), and the refractive index of the substrate, n
_s, and the refractive index of air and _{n a, n x = n s} · v (x) +
_{n a (1-v (x} )) is expressed as. Therefore, when minute irregularities are formed and the volume fraction v ( _x ) of the substrate is continuously changed, the refractive index also changes continuously, and the film becomes an inhomogeneous film, thereby preventing reflection.

When the ultrafine particle film is etched, irregularities having a size equal to or smaller than that of the ultrafine particles are formed, and the film becomes a heterogeneous film as described above, and becomes an effective antireflection film.
The same applies to the treatment of irregularities on the surface of ultrafine particles, the formation of porous material, and the formation of fine particles by aggregation.

(Ingenuity of Antireflection Function Ultrafine Particles) FIG. 8
Exemplifies an embodiment of the antireflection function ultrafine particles.

(A) has a porous surface, each opening diameter is 0.05 μm or less, the opening ratio is about 50%, and the spherical surface is not uniformly (substantially uniform). . The total diameter is preferably 0.1 μm or less on average. One example of a porous technique is a nucleus growth method. In this case, for example, when the mixing ratio of the starting materials of alkoxide-water-acid-alcohol is changed and the hydrolysis and polymerization reaction is not uniform or the reaction is accelerated, a portion having a high water concentration is generated inside. When these are baked, moisture evaporates, and the traces become voids and become porous.

(B) shows comparatively large ultrafine particles (in this case, those having a radius particle size of 0.15 μm or less) provided with ultra-fine particles having a smaller diameter than the ultrafine particles. 0.2 μm or less is preferable. In this case, A in the figure
And B are blended at an appropriate ratio to obtain A by mechanical friction.
The surface is activated and B is adsorbed (mechanical, fusion).

(C) is a modification of this type (b). For example, when a solution in which ultrafine particles of SiO ₂ are monodispersed is further reacted, a solution in which a large number of secondary aggregated particles are present is obtained. These are dried and then mechanically pulverized to obtain secondary aggregates of a certain size. Also in this case, it is desirable that the total average diameter of the aggregate 1 is 0.2 μm or less.

(D) and (e) are perspective views of the types (b) and (c). (D) is an example of an aggregate of ultrafine particles of 0.05 μm or less. ) Is an example of an aggregate of ultrafine particles of 0.1 μm or less, and the overall average diameter is also 0.1 μm.
It is preferably 2 μm or less.

(Example of Forming Two-Layer Film) FIG. 9 is a cross-sectional view of an example in which the ultrafine particle film of the present invention is formed in two layers on a glass substrate, and FIG. It is a figure showing a change of a refractive index. Each ultrafine particle is according to any one of the modes shown in FIG.

First, ethyl silicate [Si (OC
₂ H _{5) 4]} was dissolved in ethanol and further water, nitric acid, isopropyl alcohol, a solvent was added acetylacetone was sufficiently dispersed by ultrasonic vibration by adding SiO ₂ ultrafine particles. The amount of the SiO ₂ ultrafine particles was 25 g per 1 liter of the solvent. After dispersing the SiO ₂ ultrafine particles, citraconic acid was further added and dissolved sufficiently. The amount of citraconic acid was 10 g per liter of the solvent. afterwards,
Further, ultrasonic vibration was applied to sufficiently disperse the SiO ₂ ultrafine particles and sufficiently mix each component. The solvent after the above mixing is referred to as a solvent A.

To the solvent A, a solvent B in which ultrafine MgF ₂ particles and ethyl silicate were previously dispersed in ethanol was added, and the mixture was uniformly mixed by ultrasonic vibration. The amount of MgF ₂ ultrafine particles in solvent B is about 25 g per liter of solvent.
It is. By changing the mixing ratio of the solvent A and the solvent B, SiO ₂
Changing the mixing ratio of the ultrafine particles and MgF ₂ ultrafine particles.

First, a solvent obtained by mixing the solvent A and the solvent B was dropped onto the glass plate surface so that the volume fraction of the SiO ₂ ultrafine particles and the MgF ₂ ultrafine particles became 7: 3. After coating, the coating film was dried by keeping it at 40 ° C. for about 10 minutes in air. After drying, additional SiO ₂
Ultrafine particles and MgF ₂ ultrafine particle volume fraction of 1: was added dropwise mixed solvent to be 1, was uniformly applied with a spinner. Thereafter, the mixture was calcined at 160 ° C. for 45 minutes in the air, and ethyl silicate was thermally decomposed into SiO ₂ . MgF ₂
Ultrafine particles, SiO ₂ SiO ₂ ultrafine particles produced by pyrolysis
Thus, it is firmly fixed on the glass substrate.

The cross section of the ultrafine particle film thus formed was observed with an electron microscope.
The layer (first layer) in which the O ₂ ultrafine particles 52 and the MgF ₂ ultrafine particles 51 are 7: 3 is about 0.1 μm, and the layer (1st layer) is 1: 1 (second layer).
Layer) is about 0.1μm in total about 0.2μm thickness, SiO ₂
Ultrafine particles, MgF ₂ ultrafine particles are uniformly mixed, films densely deposited was observed. 53 is a glass substrate.

[0203] The above ultrafine particle film, the result of the change in average屈降rate with respect to the film thickness direction was calculated from the SiO ₂ ultrafine particles and MgF ₂ ultrafine particle volume fraction is shown in FIG. 10. a is a refractive index of air of about 1.0, and b is a refractive index of about 1.42 of the first layer.
, C is the refractive index of the second layer, about 1.44, and d is the refractive index of soda glass, about 1.53. Since the refractive index of the film as a whole is gradually changing, there is an effect of reducing the reflectance at the interface between the coating film and the glass substrate. Further, since the film is formed by the ultrafine particles, minute irregularities are generated on the surface of the coating film, and the reflection on the surface of the coating film is reduced.

A wavelength of 4 at an incident angle of 5 ° was applied to the glass substrate on which the ultrafine particle film was formed and the untreated glass substrate.
Light having a wavelength of 00 to 700 nm was made incident, the reflectance was measured, and the results are shown in FIG. In the figure, I is the reflection characteristic of the glass plate on which the ultrafine particle film is formed, and II is the reflection characteristic of the untreated glass plate.

In the entire wavelength range, the antireflection film of the present invention has a reflectance reduced to about １ ／ of that of an untreated glass plate.
When the transmittance is represented by an integrated value between the wavelengths of 400 to 700 nm, the glass plate on which the antireflection film of the present invention is formed is about 86% while the untreated glass plate is 92%. Since it has low reflection in the entire visible light region and high transmittance, it is suitable as an antireflection film for a VDT (visual display terminal).

In the present embodiment, two layers having different mixing ratios are used. However, the antireflection effect can be further increased if the average refractive index is changed more gradually with more layers.

According to this embodiment, a film whose refractive index changes continuously can be formed by repeating a simple coating method, so that an antireflection film can be manufactured at low cost and a large-area antireflection film can be easily formed. There is an effect that can be formed.

(Example in the case of component-mixed ultrafine particles) FIG. 12 is a sectional view in which an antireflection film is formed on a glass substrate.

[0209] In this example, a single layer of ultrafine particle thin film is formed on a glass substrate 48. The ultrafine particle thin film is mainly composed of ultrafine particles 46, and each of the ultrafine particles is a mixture of a conductive component 46D and an antireflection function component 46C, and has a surface porous as shown in an enlarged drawing of FIG. 8 is good). The conductive component 46 </ b> D is, as it were, ultrafine particles and may be present outside the ultrafine particles 46. In this example, the ultrafine particles are covered with the SiO ₂ thin film 46E, but the present invention is not limited to this. That is, the ultrafine particles may be left uncovered without being coated with the SiO ₂ coating. An SiO ₂ filling portion 46F is formed in the gap between the ultrafine particles and the glass substrate 48.

The SiO ₂ thin film 46E and the SiO ₂ filling portion 46
F is a fired decomposition product of Si (OR) ₄ .

In this example, Sn is used as the conductive component 46D.
O ₂ is used, and SiO ₂ is used as the antireflection function component 46C. The volume ratio of SnO ₂ / SiO _{2 in} the components is 0.1.
1 (10%) or more and 0.5 (50%) or less. In this case, the ratio of the conductive functional component during film formation in the ultrafine particles is 1% or more and 50% or less in terms of% by weight, In this case, the calculation is performed excluding the SiO ₂ thin film 46E and the SiO ₂ filling portion 46F.

[0212] The distance between the ultrafine particles must be such that the distance between the conductive components contained in adjacent ultrafine particles is maintained at such a length that a so-called tunnel effect is exhibited. . 0.05μ for such a distance
m or less is preferred.

Since the average particle size of the ultrafine particles (the thickness of one thin film) is 0.1 μm or less, the thickness of the thin film is allowed to be 0.1 μm to 0.2 μm. The depth of the valley of the thin film formed between the particles is usually 0.05μ.
m to 0.2 μm (when covered with a SiO ₂ thin film, the height of the valley is 0.05 μm to 0.2 μm).

Since SiO _{2, which} is a decomposition product of Si (OR) ₄ , enters the gap between the ultrafine particles and the thin film, it also serves as an adhesive.

Next, the reason that the antireflection film of this example has a high mechanical strength is that the SiO ( ₂₎ film formed by hydrolysis of Si (OR) ₄ as follows exists, and this is the protection. This is probably due to the film.

Si (OC ₂ H ₅ ) ₄ + 4H ₂ O → Si (OH) ₄
+ 4C ₂ H ₅ OH → SiO ₂ + 5H ₂ O Further, since fine irregularities due to the ultrafine particles according to the present invention are regularly and uniformly formed on a flat plate, a good antireflection effect can be obtained over the entire surface. In addition, the resolution does not decrease due to unnecessary irregularities.

(Thin Film Forming Example) An example in which the present invention is applied to the front panel surface (glass face plate) of a cathode ray tube is shown below.

Tetraethoxysilane [Si (OC ₂ H ₅ )
₄ ] is dissolved in ethanol, and a solution is prepared by adding water (H ₂ O) for the field of water addition and nitric acid (HNO ₃ ) as a dissolving agent. To the alcohol solution, 1 g of ultrafine particles (particles having a substantially spherical shape) 1 sized in the same manner as in the above embodiment is added. At this time, an appropriate amount of acetylacetone is added as a dispersion medium so that the particles are sufficiently dispersed.

Before adding the ultrafine particles 1, predetermined amounts of various additives shown in Table 1 were added to the alcohol solution.

[0220]

[Table 1]

The compounding solution shown in Table 1 was dropped on a glass face plate, and further uniformly applied with a spinner.

Thereafter, the mixture is calcined at 150 ° C. for about 30 minutes in air to decompose tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ]. The ultrafine particles added to the alcohol solution are firmly fixed by a continuous and uniform thin film of SiO ₂ formed by decomposition, and irregularities are formed on the glass face plate. The structure of the antireflection film is the same as that shown in FIG.
4 ′ is SiO ₂ formed by decomposition of tetraethoxysilane.
Part, which contains an antistatic component as an additive.

The method for applying the solvent is not limited to the spinning method described above, but may be a dipping method, a coating method, a spray method, or a combination thereof. The firing temperature after the application is suitably about 50 to 200 ° C.

The glass face plate on which the antireflection film was formed
The light was incident at an incident angle of ° and the reflectance was measured. As shown in Table 1, at a wavelength of 500 nm, 0.5% or less was obtained.
The reflectance was 1% or less in the wavelength range of 450 to 650 nm. This value is the VDT (visual display
This is a value that sufficiently satisfies the conditions as a terminal).

Next, the surface of the glass face plate on which the antireflection film was formed was rubbed evenly 50 times with an eraser [Lion Office Equipment Co., Ltd., trade name: Lion 50-50] under a pressure of 1 kg. As shown in Table 1 for the strength,
Only an increase of about 0.1 to 0.2% caused no problem in quality. For comparison, a similar test was performed on a glass face plate on which concavities and convexities were formed by conventional etching, and a single rub of the eraser increased the reflectance by 2%.
Five rubs resulted in exactly the same reflectance as the untreated glass faceplate.

Further, as shown in Table 1, it is considered that the reason why the low surface resistance is obtained is that various antistatic components in the solution work effectively and do not significantly affect the antireflection performance and the film strength.

Further, as a process of forming such an anti-reflective coating, a commercially available SiO ₂ fine particle is added to an existing Si (OR) ₄ alcohol solution, which can be directly formed on a finished sphere, coated and baked. It is possible to manufacture completely and at low cost without using any harmful chemicals such as hydrofluoric acid.

The ultrafine particles 1 are not limited to a spherical shape but may be an irregular shape. However, if the particle size of the ultrafine particles is too small, the outermost surface of the formed film may be too smooth and a sufficient antireflection effect may not be obtained. Conversely, if it is too large, the diffusion effect will be too large and the resolution will decrease, and the film strength will also decrease,
An average particle size of 0.1 μm or less, defined as so-called ultrafine particles, is preferred.

The method of applying the alcohol solution of Si (OR) ₄ to which ultrafine particles are added is not limited to the spinning method described in the above embodiment, but may be a dipping method, a coating method, a spray method, a combination thereof, or the like. The firing temperature after the application is suitably about 50 to 200 ° C.

Further, in the above-described embodiment, the example where R is an ethyl group as Si (OR) ₄ is described.
When the C _n H _2n + _1, may be embodied in a range of n = 1 to 5, and when n is large, the viscosity of the solution becomes slightly higher, as the solvent corresponding thereto in consideration of the workability All you have to do is choose alcohol.

Further, as an example of the metal salt as an additive for imparting an antistatic effect, an aluminum salt is shown as a representative example.
The same effect can be obtained with any of the salts of Group III and III metal elements. Although the conductive metal oxide is exemplified by SnO ₂ in the examples, other well-known examples such as I 2
_{n 2 O 3, Sb 2 O} 3, complex metal oxides such as LaNiO ₃ having a perovskite _{structure, La 1 - x Sr x C} 0 O
₃ (These have a specific resistance of 10 to ⁴ Ωc at room temperature.
m).

According to this embodiment, an image display panel having an antireflection film having excellent antireflection effect and mechanically strong antistatic function can be obtained. Moreover, this face plate of the present invention can be manufactured by a simple and safe process without using harmful treatment chemicals such as hydrofluoric acid, is suitable for mass production, and has excellent stain resistance.

(Example of forming a thin film) In 1 g of nitric acid, 0.2 g of the above-mentioned oxide ultrafine particles having an antireflection function was dispersed, and 5 g of a silicate alcohol solution, 5 g of acetylacetone, and 0.1 g of dicarboxylic acid were added to this solution. , Stirring,
Dispersed. This solution was dropped on a glass substrate, and 600 rpm
At 160 ° C. for 30 minutes.
Calcined for minutes. The specular reflectance at 5 ° of the formed film is 400 to 70.
0.06% in a visible region of 0 nm, and a surface resistance of 0.5 to 1
× 10 ⁷ Ω / □.

The surface resistance when a film is formed in the same manner as in the above embodiment by using a mixture of materials obtained by separately forming ultrafine particles of SiO _{2 and} ultrafine particles of SnO ₂ + Sb ₂ O ₃ is several tens of G
Ω / □.

As described above, according to the present embodiment, at least two or more kinds of oxide ultrafine particles can be formed in a substantially uniform mixed form by using an arc heat source. Further, a film having a combined function of conductivity and antireflection can be formed by a single coating operation using the oxide mixed ultrafine particles.

The same oxide mixed ultrafine particles can be obtained by using Ar-O ₂ induction plasma or arc plasma as a heat source for generating oxide mixed ultrafine particles, and adding the mixed powder to the plasma.

(Example of forming base transparent conductive film + antireflection film)
A base transparent conductive film is formed on the front panel surface (glass face plate) of the cathode ray tube as in Examples 7 to 10 shown in Table 2.

In the case of Example 7, the conductive film was composed of SnO ₂ , and the film was formed by a CVD method under the following conditions.

Apparatus used: normal pressure CVD apparatus Raw material organotin compound: Sn (CH ₃ ) ₄ Dopant: Freon gas Carrier gas: N ₂ Substrate temperature (glass face plate): 350 ° C. In the case of Example 8, the SiO ₂ thin film was used. The transparent conductive fine powder contains SnO ₂ fine powder, and the method of forming the film is as follows.

[0240] (1) alkoxysilane Si (OR) ₄ in the composition of the alcohol solution: ethyl alcohol (C ₂ H ₅ OH) 88cc tetraethoxysilane _{(Si (OC 2 H 5)} 4) transparent conductive 6 cc SnO ₂ fine Powder 1.2 g Water (H ₂ O) 6 cc (2) Solution coating on glass face plate: Spinner 500 rpm (3) Coating film baking: 160 ° C., 30 minutes As transparent conductive powder, instead of SnO ₂ described above. Similar trials were conducted for those in which In ₂ O ₃ , Sb ₂ O _3, etc. were added alone or in combination, but the results were almost the same. Therefore, here, SnO ₂ powder was used as a representative example as described above.

In the case of the ninth embodiment, In ₂ O ₃ and SnO
₂ (5 wt%), and a film obtained by depositing a mixture of In ₂ O ₃ and SnO ₂ on a glass face plate by high frequency sputtering.

[0242] In the case of Example 10, as a metal salt having a hygroscopicity SiO ₂ thin film, aluminum nitrate Al (N
O _{3) 3} · 9H ₂ O in which was contained, the method of forming the film are as follows.

(1) Composition of alcohol solution of alkoxysilane Si (OR) ₄ : Ethyl alcohol (C ₂ H ₅ OH) 88 cc Etraethoxysilane (Si (OC ₂ H ₅ ) ₄ ) 6 cc Metal salt Al (NO ₃ ) ₃ · 9H ₂ 1.2 g water _{(H 2 O) 6cc (2} ) solution coating to the glass faceplate: spinner 500 rpm (3) coated film baking: 160 ° C., instead of 30 minutes the above aluminum nitrate as the metal salt AlCl ₃ , Ca (NO ₃ ) ₂ , Mg (NO ₃ ) ₂ , ZnCl _2, etc. were used alone or in combination, but the results were almost the same. As a typical example, aluminum nitrate was used.

Next, a thin film serving as an antireflection film was formed on the underlying conductive film obtained as described above by the following method.

Tetraethoxysilane [Si (OC
₂ H ₅ ) ₄ ] is dissolved in ethanol, and a solution is prepared by further adding water (H ₂ O) for hydrolysis and nitric acid (HNO ₃ ) as a dissolving agent. Particle sizes of 500 to 10 are added to this alcohol solution.
1% by weight (wt)% of fine particles of SiO ₂ (the particle shape is almost spherical) sized to 00 °. At this time, an appropriate amount of acetylacetone is added as a dispersion medium so that the particles are sufficiently dispersed.

[0246]

[Table 2]

The compounding solution shown in Table 2 was dropped on the underlying conductive film on the glass face plate, and further uniformly applied with a spinner.

Thereafter, the mixture is calcined at 150 ° C. for about 30 minutes in the air to decompose tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ]. The SiO ₂ fine particles added to the alcohol solution are firmly fixed by a continuous and uniform thin film of SiO ₂ formed by decomposition.

Next, the substrate was immersed in a 5 wt% NaOH aqueous solution for about 15 seconds to perform an etching treatment, washed with water and dried, and subjected to various tests.

The glass face plate on which the antireflection film was formed
A light having a wavelength of 550 nm was incident at an incident angle of ° and its reflectance (direct opposite light intensity) was measured. The similar reflected light intensity in an Al vapor-deposited film was defined as 100 and expressed as a percentage.
As shown in the figure, the reflectance was 0.4% or less, and the reflectance was 1% or less in the visible light range of wavelengths of 450 to 650 nm. The spectrophotometer uses U-3400 manufactured by Hitachi, Ltd. (the same applies hereinafter). This value sufficiently satisfies the conditions required for a VDT (Visual Display Terminal).

Next, the surface of the glass face plate on which the underlying conductive film and the anti-reflection film were laminated was strongly erased (Lion 50-50, manufactured by Lion Office Equipment Co., Ltd.) with a strong pressure (printing pressure 1).
(kgf, rubber eraser cross-sectional area: 18 × 10 mm) After rubbing 50 times uniformly, the reflectance shifted only by about 0.1% to 0.2%, and there was no problem in quality.

In the rubber erasing test, a 60-degree specular gloss (see JIS, K5100) before and after rubbing 50 times is measured.

(Example of Adding Particle Size Distribution) Next, an example in which a particle size distribution is provided will be described. In the example of giving the particle size distribution, the pattern of FIG. 8 is applied to each ultrafine particle.

FIG. 13 shows the particle size distribution of the SiO ₂ ultrafine particles.
The average particle size is 450 nm, has a fairly wide particle size distribution, and the specific surface area is 70-80 m ² / g. These ultrafine particles are added to a 1 wt% Si (OR) ₄ alcohol solution + 50
% Acetylacetone solution, applied to a glass substrate by spin coating, and then baked at 160 ° C. for 30 minutes.

The composition of the coating solution was SiO ₂ ultrafine particles 1-2.
Wt%, a balance Si (OC ₂ H _{5) 4} and 50% acetylacetone, was coated under the conditions of a spinner 600 rpm × 30 seconds, 160 ° C., was dried and baked at 30 minutes.

By using ultrafine particles having a particle size distribution as in this example, a film having appropriate holes was obtained. The reflection characteristic of this film measured after performing the etching treatment as described above is 0.0 in the visible light region (400 to 700 nm).
6-0.3%. Further, a film having a transmittance of 90% or more can be obtained by applying and firing a Si (OR) ₄ alcohol solution + 50% acetylacetone solution on this film.
According to this embodiment, there is an effect that a good antireflection film can be obtained by a simple method.

It is preferable that the surface of the glass substrate is cleaned and preheated to about 50 ° C. before forming the antireflection film.

[0258]

According to the present invention, since fine irregularities due to ultrafine particles can be formed by a simple coating method, a charge and antireflection film can be manufactured at low cost. The present invention is naturally applicable to a metal body, a light absorber, and an opaque body.

[Brief description of the drawings]

FIG. 1 is a layout view of an apparatus according to an embodiment of the present invention.

FIG. 2 is a reflectance characteristic diagram when the ultrafine particle film of the present invention is applied to an antireflection film.

FIG. 3 is a charging characteristic diagram when the ultrafine particle film of the present invention is applied to an antistatic film.

FIG. 4 is a general sectional view of a cathode ray tube which is an application example of the present invention.

FIG. 5 is a schematic sectional view of an ultrafine particle film according to one embodiment of the present invention.

FIG. 6 is a diagram showing a film thickness characteristic of an ultrafine particle film according to one example of the present invention.

FIG. 7 is a layout view of an apparatus according to another embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view of ultrafine particles according to one example of the present invention.

FIG. 9 is a sectional view of an antireflection film according to one embodiment of the present invention.

FIG. 10 is a characteristic diagram showing a change in a refractive index in a thickness direction of an antireflection film.

FIG. 11 is a characteristic diagram showing the reflectance of the antireflection film and the untreated glass plate according to one embodiment of the present invention between wavelengths of 400 to 700 mm.

FIG. 12 is a sectional view of an antireflection film according to one embodiment of the present invention.

FIG. 13 is a particle size distribution diagram of an example having a particle size distribution.

[Explanation of symbols]

11 ... CRT, 12 ... Coating bath, 13 ... Coating solution,
14 ... Pressure adjustment valve, 15 ... Overflow valve, 16 ... Solution tank, 17 ... Solution supply pressure valve, 1
8 ... Leak valve.

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Takao Kawamura 3300 Hayano Mobara-shi, Chiba Pref.Hitachi, Ltd.Mobara Plant, Hitachi, Ltd. (72) Inventor Katsumi Ohara 3300 Hayano Mobara-shi, Chiba Pref. Hitachi, Ltd. Mobara Factory (56) References JP-A-3-150501 (JP, A) JP-A-1-154444 (JP, A) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) H01J 29/88 G02B 1/11

Claims (4)

(57) [Claims] 1. An anti-reflection body comprising a substrate provided with a coating in which ultra-fine particles having an anti-reflection function are dispersed, wherein said ultra-fine particles have a particle size of 0.1 to 0.15 μm and a surface of 0.1 to 0.15 μm. An anti-reflective body characterized in that it is made porous with an opening diameter of not more than 05 μm. 2. The anti-reflection body according to claim 1, wherein ultra-fine particles having an antistatic function are dispersed in said coating in addition to said ultra-fine particles having said anti-reflection function. 3. The antireflection body according to claim 2, wherein said ultrafine particles having an antistatic function are SnO ₂ , SnO _2.
An anti-reflection member, which is selected from the group consisting of + Sb ₂ O ₃ , In ₂ O ₃ , In ₂ O ₃ + Sb ₂ O ₃ . 4. A transparent plate having an ultrafine particle film formed of an ultrafine particle group and a binder filling each ultrafine particle gap formed on a transparent substrate, wherein a coupling agent having a functional group for the substrate material is added to the inside of the ultrafine particle film. And / or present at the interface between the ultrafine particle film and the transparent substrate, wherein the ultrafine particles have a particle diameter of 0.1 to 0.15 μm, and the surface thereof has a pore size of 0.05 μm or less. A transparent plate, characterized in that: