JP2002071911A - Transparent base material with low transmittance, method of manufacturing the same, and display device adapting transparent base material with low transmittance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent base material having a low transmittance which has a flat transmission spectrum, and to which a low reflectance and antistatic and electric shielding functions can be added, and of which production cost can be reduced and a method of manufacturing the material, and also to provide a display device to which the transparent base material with a low transmittance is adapted. SOLUTION: The transparent base material with a low transmittance has a transparent substrate and a transparent layer with a low transmittance formed on the substrate. The transparent layer with a low transmittance essentially comprises black pigment fine particles having 5 to 150 nm average particle size and a binder matrix. The black pigment fine particles consists of single titanium nitride fine particles or a mixture of titanium nitride fine particles and carbon fine particles. The transmittance for visible rays of the transparent layer with low transmittance ranges from 20-80% and the standard deviation of the transmittance in the transparent layer with low transmittance at every 5 nm wavelength in the visible ray region (380 to 780 nm) ranges from 0 to 6%. Further, the transparent layer with low transmittance contains conductive oxide fine particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a low-transmittance transparent layer or a two-layer transparent film comprising a low-transmittance transparent layer and a transparent coat layer on a transparent substrate.
T) The present invention relates to a low-transmittance transparent base material used for a front panel of a display device or the like, particularly having a flat transmission spectrum, excellent mechanical strength and weather resistance, low reflectance and antistatic property. Also, the present invention relates to a low-transmittance transparent base material to which an electric field shielding function can be added and which can reduce the manufacturing cost, a manufacturing method thereof, and a display device to which the low-transmittance transparent base material is applied.

[0002]

2. Description of the Related Art With the recent shift to office automation (OA) in offices, there is an increasing number of opportunities to work in contact with a cathode ray tube (CRT) display of a computer.

[0003] By the way, the display is required to be easy to see the display screen and not to cause visual fatigue.
Also, home color televisions are required to be easily viewable on display screens. In order to meet these demands, the front glass of the CRT may be subjected to a process of lowering the transmittance and improving the contrast.

In this case, a method of using a face panel having a low transmittance (a front panel of a CRT) and a method of applying a coating film having a low transmittance to a face panel having a relatively high transmittance can be considered. The latter method is advantageous in that the latter can be controlled freely.

Therefore, a method of coating a front glass of a CRT with a coating liquid in which fine particles of black pigment are dispersed in a solvent has been studied.

Examples of black pigments applicable to this method include carbon, iron oxide (Fe ₃ O ₄ ), titanium black, and a composite oxide of iron, manganese and copper. As a black pigment excellent in carbon black, carbon is cited (see Japanese Patent Application No. 11-354775). However, when a method of coating a front glass of a CRT with a coating liquid in which carbon fine particles are dispersed in a solvent is adopted, the transmission spectrum of the coating film is short in visible light as shown in FIG. 5 (Comparative Example 1). There is a problem in that the color is reduced on the wavelength side and becomes a brownish transmitted color.

[0007] As another attempt to make the display screen easier to see, a method has been performed in which the face panel surface is subjected to an anti-glare treatment to suppress the reflection of the screen. As this anti-glare treatment, for example, there is a method of increasing the diffuse reflection of the surface by providing fine irregularities on the face panel surface. However, when this method is used, the resolution is lowered and the image quality is lowered, but it is not so preferable. Absent. Therefore, it is preferable to perform the anti-glare treatment by an interference method that controls the refractive index and the thickness of the transparent film so that the reflected light causes destructive interference with the incident light. In order to obtain a low reflection effect by such an interference method, generally, the optical thicknesses of the high refractive index film and the low refractive index film are set to λλ and 1 / λ.
A two-layer structure film set to 4λ, λλ and １ ／ λ (λ: wavelength) is employed.

Therefore, as a technique for making the display screen easier to see, a method combining this two-layer structure film and carbon fine particles is considered. That is, carbon fine particles are used as black pigment fine particles, a coating liquid in which the carbon fine particles are dispersed in a solvent is applied to the front glass of a CRT, dried, and then overcoated with a coating liquid mainly composed of silica sol or the like.
This is a method in which a film having a low reflectance is obtained by baking at a temperature of about the same to form the two-layer structure film.

However, as shown in FIG. 6 (Comparative Example 2), good reflection characteristics can be obtained, but the transmission spectrum of the film is not as shown in FIG.
As shown in (Comparative Example 2), there was a problem that the transmittance was reduced on the short wavelength side of visible light, and a brownish transmitted color was obtained as described above.

When performing work in contact with the CRT or the like, the CRT is required to have a display screen that is easy to see and does not cause visual fatigue, and that there is no adhesion of dust or electric shock due to surface charging. In some cases. Furthermore, recently, in addition to these, there is a concern that a low-frequency electromagnetic wave generated from the CRT may have an adverse effect on a human body, and it is desired for the CRT not to leak such an electromagnetic wave to the outside.

As a countermeasure for preventing such charge and preventing electromagnetic wave leakage, a method of forming a transparent conductive layer on the front glass surface of the CRT has been studied. The surface resistance of these transparent conductive layers is 10 ⁸ to 10 ¹¹ for antistatic purposes.
Ω / □, and at least 10 to prevent electromagnetic wave leakage
⁶ Ω / □ or less is desired.

In order to cope with these demands, there is known a method of forming the transparent conductive layer using tin antimony oxide (ATO) fine particles or indium tin oxide (ITO) fine particles as the transparent conductive fine particles. I have. That is, a coating liquid in which the above-mentioned transparent conductive fine particles are dispersed in a solvent together with a binder such as an alkyl silicate is applied to a front glass of a CRT, dried, and fired at a temperature of about 200 ° C. to form a transparent conductive layer. How to

However, since the transparent conductive fine particles used in this method do not absorb visible light, in order to obtain the low transmittance coating film for improving contrast, black pigment fine particles such as titanium black are coated with the transparent conductive fine particles. Layer had to be contained (JP-A-9-76401,
See JP-A-9-78008.

However, titanium black is inferior in hiding power (coloring power) as compared with carbon. Therefore, in order to reduce the visible light transmittance of the transparent conductive layer to a low transmittance of 80% or less, the amount of titanium black in the coating liquid is required. Therefore, there is a problem that properties such as film strength and conductivity are deteriorated, and when carbon fine particles having excellent hiding power (coloring power) are contained instead of titanium black, Similarly, there was a problem that a flat transmittance profile was not obtained and the film was colored brownish.

An antireflection film in which an organic pigment such as phthalocyanine blue is contained in the lower layer side of the two-layer structure film is also known (see JP-A-7-151903).

Since the antireflection film uses phthalocyanine blue or the like instead of carbon fine particles, the coloring problem caused by carbon fine particles can be avoided.

However, the bond between the organic pigment phthalocyanine blue and the silicon oxide binder in the film is weak,
This causes a problem that the mechanical strength of the anti-reflection film is insufficient, and the weather resistance of the anti-reflection film is poor because the organic pigment such as phthalocyanine blue has lower weather resistance than the inorganic pigment. Had a sufficient problem.

[0018]

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and has as its object to have a flat transmission spectrum and excellent mechanical strength and weather resistance. At the same time, a low-reflectance transparent base material which can also add a low reflectance and an antistatic or electric-field shielding function, and which can reduce the manufacturing cost, a manufacturing method thereof, and the low-transmittance transparent base material are applied. A display device is provided.

[0019]

That is, the invention according to claim 1 is based on the premise that a transparent substrate and a low-transmittance transparent base material having a low-transmittance transparent layer formed on the transparent substrate are provided. The low transmittance transparent layer is mainly composed of black pigment fine particles having an average particle size of 5 to 150 nm and a binder matrix, and the black pigment fine particles are composed of titanium nitride fine particles alone or a mixture of titanium nitride fine particles and carbon fine particles. And the visible light transmittance of the low transmittance transparent layer is 20 to 80%, and the visible light wavelength range (380
The standard deviation of the transmittance of the low transmittance transparent layer at each wavelength of every 5 nm (from 780 nm to 780 nm) is 0 to 6%, and the invention according to claim 2 is characterized in that: Assuming a low-transmittance transparent substrate having a transparent two-layer film composed of a low-transmittance transparent layer and a transparent coat layer formed sequentially on the substrate, the low-transmittance transparent layer has an average particle size of 5 to 150 n.
m and a binder matrix. The black pigment fine particles are composed of titanium nitride fine particles alone or a mixture of titanium nitride fine particles and carbon fine particles. The reflectance at which the reflection spectrum is minimized in the region is 3% or less, and the visible light transmittance of the transparent two-layer film is 20 to 8
0% and visible light wavelength range (380 to 780 nm)
Wherein the standard deviation of the transmittance of the transparent two-layer film at each wavelength of 5 nm is 0 to 6%.

The invention according to claim 3 is based on the low transmittance transparent base material according to claim 1 or 2, wherein the mixing ratio in the mixture of the titanium nitride fine particles and the carbon fine particles is 100%. The carbon fine particles are set to 200 parts by weight or less with respect to parts by weight, and the invention according to claim 4 is based on the low transmittance transparent base material according to claim 1 or 2, and The blend ratio of the black pigment fine particles and the binder matrix in the transparent layer is set to 100 to 1100 parts by weight of the binder matrix with respect to 100 parts by weight of the black pigment fine particles.

Next, the invention according to claims 5 to 7 relates to an invention in which a low transmittance transparent base material having an antistatic or electric field shielding function is specified.

That is, the invention according to claim 5 is based on the low transmittance transparent base material according to claim 1, wherein the low transmittance transparent layer contains conductive oxide fine particles having an average particle size of 10 to 150 nm. And the compounding ratio of the conductive oxide fine particles is 50 to 1000 with respect to 100 parts by weight of the black pigment fine particles.
The present invention according to claim 6 is characterized in that the low transmittance is set in parts by weight and the surface resistance of the low transmittance transparent layer is 10 ⁴ to 10 ¹¹ Ω / □. Assuming a transparent base material, an average particle size of 1
0 to 150 nm conductive oxide fine particles are included, and
When the mixing ratio of the conductive oxide fine particles is 1
The weight is set to 50 to 1000 parts by weight with respect to 00 parts by weight, and the surface resistance of the transparent two-layer film is 10 ⁴ to 10 parts by weight.
^The invention according to claim 7 is based on the premise of the low transmittance transparent base material according to claim 5 or 6, wherein the conductive oxide fine particles are indium tin oxide. The invention according to claim 8 is at least one kind of fine particles selected from fine particles or tin antimony oxide fine particles, and the low transmittance transparent substrate according to any one of claims 1 to 7 It is assumed that the binder matrix of the low transmittance transparent layer and the transparent coat layer contain silicon oxide as a main component.

Next, the invention according to claims 9 to 17 relates to the invention which specifies the method for producing the low transmittance transparent base material according to claim 1 or 2.

That is, the invention according to claim 9 is based on the method for producing a low-transmittance transparent base material according to claim 1, and comprises a solvent, titanium nitride fine particles alone or carbon fine particles dispersed in this solvent and titanium nitride. 11. A black pigment fine particle having an average particle diameter of 5 to 150 nm comprising a mixture of fine particles, and a coating liquid containing an inorganic binder as a main component is applied on a transparent substrate, and then subjected to heat treatment. The invention is based on the method for producing a low-transmittance transparent base material according to claim 9, wherein the mixing ratio of the black pigment fine particles and the inorganic binder in the coating liquid is 100 parts by weight of the black pigment fine particles. The amount is set to 100 to 1100 parts by weight, and the invention according to claim 11,
Assuming that the method for producing a low-transmittance transparent substrate according to claim 9 or 10, the coating liquid has an average particle size of 10 to 150 nm.
And the mixing ratio of the conductive oxide fine particles is set to 50 to 1000 parts by weight based on 100 parts by weight of the black pigment fine particles.

The invention according to claim 12 is based on claim 2.
A black pigment having an average particle diameter of 5 to 150 nm, which is composed of a solvent and titanium nitride fine particles alone or a mixture of titanium nitride fine particles and carbon fine particles dispersed in the solvent, on the premise of the method for producing a low-transmittance transparent substrate described in the above. The invention according to claim 13, wherein a coating liquid containing fine particles as a main component is applied on a transparent substrate, and then a coating liquid for forming a transparent coat layer is applied, followed by heat treatment. Assuming a method for producing a low-transmittance transparent substrate, an average particle size of 1
0 to 150 nm conductive oxide fine particles are included, and
When the mixing ratio of the conductive oxide fine particles is 1
It is characterized by being set to 50 to 1000 parts by weight with respect to 00 parts by weight.

The invention according to claim 14 is the first invention.
Assuming the method for producing a low-transmittance transparent substrate according to 2 or 13, the coating liquid contains an inorganic binder, and the invention according to claim 15 is the invention according to claim 11 or 13. Wherein the conductive oxide fine particles are at least one type of fine particles selected from indium tin oxide fine particles or tin antimony oxide fine particles, The invention according to Item 16 is based on the method for producing a low-transmittance transparent substrate according to any one of Claims 9 to 15, wherein the mixing ratio in the mixture of the titanium nitride fine particles and the carbon fine particles is titanium nitride fine particles. Carbon fine particles 2 per 100 parts by weight
It is characterized in that it is set to not more than 00 parts by weight, and the invention according to claim 17 is based on the method for producing a low-transmittance transparent base material according to claim 12 or 14, and forms the transparent coat layer. The coating liquid for use and the inorganic binder of the coating liquid are mainly composed of silica sol.

Next, the invention according to claim 18 relates to a display device in which the low transmittance transparent base material according to the present invention is incorporated.

That is, the invention according to claim 18 is based on the premise that the display device includes a device main body and a front plate disposed on the front side of the display device. The transmissive transparent substrate is incorporated with the low transmissive transparent layer or the transparent two-layer film side facing the outside.

[0029]

Embodiments of the present invention will be described below in detail.

First, as described above, as a black pigment,
Carbon, iron oxide (Fe ₃ O ₄ ), titanium black, composite oxides of iron, manganese and copper, and the like are generally known.

Titanium black is obtained by treating titanium oxide (TiO ₂ ) at a high temperature in a hydrogen atmosphere at a high temperature, or lower titanium oxide (TiO ₂ -x) or titanium oxide (TiO ₂ ). Nitrogen-containing titanium compound (Ti _x O) obtained by treating at high temperature in an atmosphere
_{YN Z} ), and the composite oxide of iron, manganese, and copper has, for example, the chemical formula: (Cu, Fe, Mn) (F
e, Mn) a compound having a spinel structure represented by ₂ O _4, CuO: _33~36 wt%, MnO: thirty to fifty-one wt%, Fe ₂ O _3: it is formed using 13 to 35 wt% .

Incidentally, among these black pigments, a material having excellent hiding power (coloring power) is carbon as described above. However, when this carbon is applied to a low transmittance transparent film, the transmission color of the film becomes brown. It is unfavorable because it becomes sexy.

According to the present invention, CRT is used because titanium nitride has a high hiding power (coloring power) equivalent to that of carbon and has a somewhat bluish color permeation when applied to a low-transmittance transparent film. Focusing on the fact that it is suitable for low transmittance transparent films for displays, etc., furthermore, the combined use of carbon fine particles in addition to titanium nitride fine particles makes the transmission profile of the film much greater than when carbon fine particles are used alone. Based on the technical discovery that the above problem can be improved, the above-mentioned problem is solved.

Here, titanium nitride is a compound represented by TiN. For example, a method of reacting titanium chloride and ammonia gas in a plasma, or a method of supplying fine titanium metal powder into a plasma in a nitrogen gas atmosphere to volatilize the titanium nitride. -It can be obtained by a reaction method or the like. When applying titanium nitride fine particles to the low transmittance transparent layer, it is necessary to apply titanium nitride fine particles alone or a mixture of titanium nitride fine particles and carbon fine particles (claims 1 and 2).

The mixing ratio in the mixture of the titanium nitride fine particles and the carbon fine particles is as follows.
It is desirable to set the carbon fines to 200 parts by weight or less based on parts by weight (claim 3), and preferably to 150 parts by weight or less. Titanium nitride fine particles 1
If the mixing ratio of the carbon fine particles exceeds 200 parts by weight with respect to 00 parts by weight, the flatness of the transmission profile of the formed low transmittance transparent layer may be deteriorated.

Further, conductive oxide fine particles are added to the low-transmittance transparent layer in order to further provide antistatic and electromagnetic wave leakage preventing functions, so that the low-transmittance transparent layer has a surface resistance of 10 ^4.
~10 ¹¹ Ω / □ (claim 5), said transparent 2-layered film of surface resistance of 10 ⁴ ~10 ¹¹ Ω / □ can be a (claim 6). As the conductive oxide fine particles, tin antimony oxide fine particles (ATO) or indium tin oxide fine particles (ITO) are preferable (claim 7), and when ATO fine particles are used, about 10 ⁸ to 10 ¹¹ Ω / □. When ITO fine particles are used, a low transmittance transparent layer or a transparent two-layer film having a surface resistance of about 10 ⁴ to 10 ⁶ Ω / □ can be obtained.

The mixing ratio of the conductive oxide fine particles is from 50 to 1000 per 100 parts by weight of the black pigment fine particles.
It is necessary to set in the range of parts by weight (claims 5 to 6),
Preferably, it is set in the range of 80 to 600 parts by weight. If the compounding ratio of the conductive oxide fine particles is less than 50 parts by weight, the contribution to the conductivity is insufficient, and on the other hand, 1000
If the amount exceeds the weight part, no further effect of improving the conductivity can be expected and the cost is not favorable.

Here, the average particle diameter of the titanium nitride fine particles and the carbon fine particles as the black pigment fine particles used in the present invention is in the range of 5 to 150 nm (claims 1 to 2). Needs to be in the range of 10 to 150 nm (claims 5 to 6). If the average particle diameter of the titanium nitride fine particles and the carbon fine particles is less than 5 nm, it is difficult to produce these fine particles, and at the same time, it is not easy to disperse in the preparation of a coating material, which is not practical. on the other hand,
If the thickness exceeds 150 nm, scattering of visible light in the formed low transmittance transparent layer increases (that is, the haze value of the film increases), which is not practical. The same applies to the average particle diameter of the conductive oxide fine particles.
Here, the average particle size means a transmission electron microscope (TE
M) shows the average particle diameter of the fine particles observed.

Next, the coating liquid used for forming the low transmittance transparent layer can be produced by the following method.

First, titanium nitride fine particles as black pigment fine particles or titanium nitride fine particles and carbon fine particles are mixed with a dispersant and a solvent, and the mixture is uniformly mixed with a dispersing device such as a paint shaker, a sand mill, or an ultrasonic disperser. A black pigment fine particle dispersion is obtained. ATO fine particles or ITO fine particles as conductive oxide fine particles are similarly mixed and dispersed to obtain a uniform conductive oxide fine particle dispersion.

The above-mentioned dispersion treatment can be carried out individually or by mixing a plurality of fine particles.
A dispersion containing both black pigment fine particles and conductive oxide fine particles can be obtained at one time.

Then, these dispersions are mixed at a predetermined ratio with an inorganic binder and / or a solvent as a binder matrix component to prepare a coating liquid used for forming the low transmittance transparent layer. Incidentally, the inorganic binder can be added at the time of the dispersion treatment.

Here, silica sol (claim 17) can be used as the inorganic binder. And, as the silica sol, an orthoalkyl silicate is hydrolyzed by adding water or an acid catalyst, and a polymer that has undergone dehydration polycondensation, or a commercially available polymer that has already undergone hydrolytic polycondensation to 4- to 5-mers A polymer or the like obtained by further proceeding hydrolysis and dehydration condensation polymerization of the alkyl silicate solution can be used. As the dehydration-condensation polymerization progresses, the solution viscosity increases and eventually solidifies. Prepare in place. However, the degree of dehydration-condensation polymerization is not particularly limited as long as the level is lower than that, but in consideration of film strength, weather resistance, etc., the weight average molecular weight is 5%.
About 00 to 3000 is preferable.

Next, the low transmittance transparent substrate of the present invention will be described in detail.

First, a low-transmittance transparent substrate according to the first aspect (ie, a low-transmittance transparent substrate having a transparent substrate and a low-transmittance transparent layer formed thereon) will be described.

In the low transmittance transparent layer, the mixing ratio of the black pigment fine particles and the binder matrix is such that the binder matrix 10
It is desirable to set the amount to 0 to 1100 parts by weight (claim 4), and it is more preferable to set the amount to 250 to 500 parts by weight. When the amount of the binder matrix is less than 100 parts by weight, the effect as a binder is not sufficiently exhibited, and the strength of the low-transmittance transparent layer is reduced, which is not practical.
When the amount exceeds 0 parts by weight, when a transparent layer having a relatively low transmittance of about 20 to 70% of visible light transmittance is formed, cracks or peeling may occur in the transparent layer when the transparent layer is cured by heating. It is.

The above-mentioned low transmittance transparent layer can be formed on a transparent substrate by the following method. For example, a solvent and an average particle diameter of 5 to 1 dispersed in the solvent.
Spray coating, spin coating, wire bar coating, doctor blade coating, gravure coating, roll coating, etc. on a transparent substrate such as a glass substrate or a plastic substrate are coated with a coating liquid containing 50 nm black pigment fine particles and an inorganic binder as main components. After applying by a technique and drying as necessary, a low-transmittance transparent layer can be formed by heat-curing at a temperature of, for example, about 50 to 500 ° C. (claim 9). Further, the above-mentioned solvent, black pigment fine particles having an average particle size of 5 to 150 nm dispersed in the solvent, and an inorganic binder were added, and AT as conductive oxide fine particles was further added.
A coating liquid containing O fine particles or ITO fine particles may be used.

As the inorganic binder, those containing silica sol as a main component can be exemplified, and the dehydration-condensation polymerization reaction is almost completed at the time of heating and sintering of the low-transmittance transparent layer to form a hard silicate film (containing silicon oxide as a main component). Film). still,
Magnesium fluoride fine particles, alumina sol, titania sol, zirconia sol, and the like can be added to the silica sol to adjust the refractive index of the low transmittance transparent layer and change its film properties (for example, reflectance).

Next, the low-transmittance transparent substrate according to claim 2 (that is, a transparent two-layer film comprising a transparent substrate and a low-transmittance transparent layer and a transparent coat layer formed sequentially on the transparent substrate) is used. The low transmittance transparent substrate provided) will be described.

In the low transmittance transparent base material, the optical constants (n−ik, n: refractive index, i ² = −
1, k: extinction coefficient) are not clear, but the transparency of a low transmittance transparent layer comprising black pigment fine particles or black pigment fine particles, conductive oxide fine particles and a binder matrix and a transparent coat layer containing silicon oxide as a main component Good low reflection characteristics can be obtained by the two-layer film structure.

Further, in the low transmittance transparent substrate,
Since the transparent coat layer containing silicon oxide as a main component is formed on the low transmittance transparent layer, the black pigment fine particles in the low transmittance transparent layer are protected by the transparent coat layer, so that the weather resistance and chemical resistance It is also effective in improving the quality.

The above-mentioned transparent two-layer film can be formed on a transparent substrate by the following method. For example, a solvent and an average particle size of 5 to 15 dispersed in the solvent.
A coating liquid containing black pigment fine particles of 0 nm as a main component is applied on a transparent substrate such as a glass substrate or a plastic substrate by a method such as spray coating, spin coating, wire bar coating, doctor blade coating, and the like. After drying, a coating liquid for forming a transparent coat layer containing silica sol or the like as a main component is overcoated by the method described above.
As the silica sol, those similar to the silica sol applied to the above-mentioned inorganic binder can be used.

Next, after overcoating, for example, 50
The transparent two-layer film is formed by curing the overcoated transparent coating layer forming liquid by heating at a temperature of about 500 ° C. (Claim 12).

Here, when the coating liquid for forming a transparent coat layer mainly composed of silica sol or the like is overcoated by the above-described method, the titanium nitride formed by the coating liquid mainly containing fine black pigment particles is applied. Overcoat silica sol solution (this silica sol solution becomes a binder matrix containing silicon oxide as a main component by the above-described heat treatment) penetrates into the gaps between the layers composed of the fine particles alone or the mixture of the titanium nitride fine particles and the carbon fine particles. And weather resistance are further improved.

In the step of forming the low transmittance transparent layer, a solvent and an average particle size of 5 to 1 dispersed in the solvent are used.
A coating liquid containing a silica sol liquid as an inorganic binder component and / or ATO fine particles or ITO fine particles as conductive oxide fine particles in addition to 50 nm black pigment fine particles may be used. In this case, as in the above case, the silica sol liquid that has been overcoated penetrates into the gap between the black pigment fine particles and the silica sol and / or the conductive oxide fine particles, thereby simultaneously improving the strength and the weather resistance.

In the above silica sol solution, the dehydration-condensation polymerization reaction is almost completely completed during the heating and firing of the transparent two-layer film to form a hard silicate film (a film mainly composed of silicon oxide). still,
Magnesium fluoride fine particles, alumina sol, titania sol, zirconia sol, and the like can be added to the silica sol to adjust the refractive index of the transparent coat layer to change the reflectance of the transparent two-layer film.

As described above, the main part of the low transmittance transparent substrate according to the present invention is constituted by the following (1) and (2). (1) a transparent substrate such as a glass substrate or a plastic substrate;
Black pigment fine particles having an average particle size of 5 to 150 nm and a binder matrix formed on the transparent substrate, or black pigment fine particles having an average particle size of 5 to 150 nm and an average particle size of 1
A low-transmittance transparent layer mainly composed of conductive oxide fine particles of 0 to 150 nm and a binder matrix. (2) a transparent substrate such as a glass substrate or a plastic substrate;
Average particle size 5 to 150 n sequentially formed on this transparent substrate
m, or a lower layer of a low-transmittance transparent layer mainly composed of black pigment fine particles having an average particle size of 5 to 150 nm, conductive oxide fine particles having an average particle size of 10 to 150 nm, and a binder matrix. A transparent two-layer film comprising an upper layer of a transparent coat layer formed on a transparent layer.

According to the low transmittance transparent substrate according to the above configuration (1), the low transmittance transparent layer has a visible light transmittance of 20 to 80%, and further has a visible light wavelength range (380
780 nm), the standard deviation of the transmittance of the low transmittance transparent layer at each wavelength of 5 nm can be set to 0 to 6%, and when the conductive oxide fine particles are contained in the low transmittance transparent layer. The surface resistance of the low transmittance transparent layer is 10 ⁴
Can be set to 〜１０10 ¹¹ Ω / □.

According to the low transmittance transparent substrate comprising the transparent two-layer film of the above (2), the visible light transmittance of the transparent two-layer film is 20 to 80% and the visible light wavelength Area (3
(80 to 780 nm), the standard deviation of the transmittance of the low transmittance transparent layer at each wavelength of 5 nm can be set to 0 to 6%, and the conductive oxide fine particles are added to the lower low transmittance transparent layer. When it is included, the surface resistance of the transparent two-layer film is 10
^{In addition to being 4} to 10 ¹¹ Ω / □, the minimum reflectance in the visible light region reflection spectrum of the low transmittance transparent substrate can be reduced to 3% or less.

As described above, the low-transmittance transparent substrate according to the present invention has a flatter transmittance profile than the conventional one, and therefore is used for, for example, a front plate of a display device such as a cathode ray tube (CRT). Can be.

[0061]

EXAMPLES Examples of the present invention will be specifically described below along with comparative examples, but the present invention is not limited to these examples. Also, “%” in the text refers to transmittance, reflectance,
Except for the haze value (%), it indicates "wt%", and
“Parts” indicates “parts by weight”.

In the following tables and drawings, the transmittance of only the low transmittance transparent layer not including the transparent substrate (glass substrate) at every 5 nm in the visible light wavelength range (380 to 780 nm) is as follows: Equation 1)
The transmittance of only a transparent two-layer film composed of a low transmittance transparent layer that does not include a transparent substrate (glass substrate) and a transparent coat layer is determined as in the following (Equation 2).

That is, the transmittance (%) of only the low transmittance transparent layer not including the transparent substrate = [(the transmittance measured for each transparent substrate) / (the transmittance of the transparent substrate)] × 100 (Equation 1) Transmittance (%) of only the transparent two-layer film not including the transparent substrate = [(transmittance measured for each transparent substrate) / (transmittance of the transparent substrate)] × 100 (Expression 2) As the transmittance and the transmission spectrum, the transmittance and the transmission spectrum of only the low transmittance transparent layer containing no transparent substrate, or only the transparent two-layer film composed of the low transmittance transparent layer and the transparent coat layer are used.

Further, the haze value and the visible light transmittance were determined for each transparent substrate using a haze meter (HR-HR, manufactured by Murakami Color Research Laboratory).
200), and the reflectance and the reflection / transmission spectrum were measured using a spectrophotometer (U-40, manufactured by Hitachi, Ltd.).
00), and the dispersed particle size of the black pigment fine particles in the dispersion was measured with a laser scattering particle size analyzer (ELS-800) manufactured by Otsuka Electronics Co., Ltd. Evaluation was performed using a transmission electron microscope manufactured by JEOL Ltd., and the surface resistance of the low transmittance transparent layer was measured using a surface resistance meter Haresta IP (MCT-HT260) manufactured by Mitsubishi Chemical Corporation.

Example 1 3.5 g of titanium nitride fine particles (manufactured by Neturen Co., Ltd.) and 0.7 g of a dispersant were mixed with 30.8 g of ethylene glycol monomethyl ether (MCS), and then mixed with zirconia beads in a paint shaker. After dispersion, a titanium nitride dispersion liquid (A
Liquid).

Next, 19.6 parts of methyl silicate 51 (trade name, manufactured by Colcoat), 70.3 parts of ethanol,
Using 7.9 parts of a 1% nitric acid aqueous solution and 2.2 parts of pure water,
A silica sol solution (solution B) having a solid content of O ₂ (silicon oxide) of 10% and a weight average molecular weight of 1360 was obtained.

Then, 0.4 g of solution A and 0.8 g of solution B
Ethanol (EA), isopropyl alcohol (IP
A), propylene glycol monomethyl ether (PG
M), and titanium nitride fine particles and an inorganic binder-containing coating liquid (TiN: 0.4%, SiO ₂ : 0.8%,
Water: 0.8%, EA: 54.9%, IPA: 8.7%,
(MCS: 3.5%, PGM: 30.0%).

As a result of observing the obtained coating solution with a transmission electron microscope, the average particle size of titanium nitride was 20 nm.

Next, this coating solution was spin-coated (150 rpm, 60 seconds) on a glass substrate (soda-lime glass having a thickness of 3 mm) heated to 40 ° C.
After curing at 0 ° C. for 30 minutes, a glass substrate with a low-transmittance transparent layer containing titanium nitride fine particles and a binder matrix, that is, a low-transmittance transparent substrate according to Example 1 was obtained.

The film properties (visible light transmittance, standard deviation of transmittance, haze value) of the low transmittance transparent layer formed on the glass substrate are shown in Table 1 below. FIG. 1 shows the transmission spectrum of the low-transmittance transparent layer according to Example 1 manufactured.

Example 2 After mixing 20.0 g of ATO fine particles (SN-100P, manufactured by Ishihara Sangyo Co., Ltd.) having an average particle diameter of 10 nm and 1.1 g of a dispersant with 78.9 g of EA, a paint shaker was dispersed together with zirconia beads. Thus, an ATO fine particle dispersion liquid (liquid C) having a dispersed particle diameter of 45 nm was obtained.

Next, 8 g of carbon fine particles [MA-7, manufactured by Mitsubishi Chemical Corporation] and 1.2 g of a dispersant were added to IPA 70.8.
After mixing with 0 g, the mixture was dispersed in a paint shaker with zirconia beads to obtain a dispersion liquid of carbon fine particles (D liquid) having a dispersed particle diameter of 100 nm.

Then, solution C (0.53 g) and solution D (0.15 g)
0.2 g of solution A of Example 1 and 0.7 g of solution B of Example 1
g, EA, IPA, PGM, titanium nitride fine particles,
Coating solution containing carbon fine particles, ATO fine particles and inorganic binder (TiN: 0.2%, carbon: 0.15%, A
_{TO: 1.05%, SiO 2:} 0.7%, water: 0.7
%, EA: 55.0%, IPA: 9.5%, MCS:
(1.8%, PGM: 30.0%).

As a result of observing the obtained coating liquid with a transmission electron microscope, it was found that titanium nitride fine particles, carbon fine particles, ATO
The average particle diameter of the fine particles is 20 nm, 40 nm, and 10 nm, respectively.
nm.

Next, a glass substrate having a low-transmittance transparent layer, that is, a low-transmittance transparent substrate according to Example 2, was obtained by using the above coating solution and following the same procedure as in Example 1.

Then, the film characteristics (visible light transmittance, standard deviation of transmittance, and the like) of the low transmittance transparent layer formed on the glass substrate
The haze value and the surface resistance are shown in Table 1 below. FIG. 2 shows the transmission spectrum of the manufactured low-transmittance transparent layer according to Example 2.

[Example 3] EA, IPA, PGM and diacetone alcohol (DAA) were added to 0.2 g of solution C of Example 2 and 0.4 g of solution A of Example 1, and titanium nitride fine particles and ATO fine particles were added. Containing coating liquid (TiN: 0.4%, AT
O: 0.4%, EA: 51.7%, IPA: 8.9%,
MCS: 3.5%, PGM: 30.0%, DAA: 5.
0%) was prepared.

As a result of observing the obtained coating liquid with a transmission electron microscope, the average particle diameters of titanium nitride fine particles and ATO fine particles were 20 nm and 10 nm, respectively.

Next, the titanium nitride fine particles and ATO
The coating solution containing fine particles is spin-coated (150 rpm, 120 seconds) on a glass substrate (soda-lime glass having a thickness of 3 mm) heated to 40 ° C., and then a silica sol solution is spin-coated (150 rpm, 60 seconds). And further cured at 180 ° C. for 30 minutes to obtain titanium nitride fine particles,
A glass substrate with a transparent two-layer film composed of a low transmittance transparent layer containing carbon fine particles and ATO fine particles and a transparent coat layer composed of a silicate film containing silicon oxide as a main component, A transmittance transparent substrate was obtained.

Here, the above silica sol solution was composed of 19.6 parts of methyl silicate 51 (trade name, manufactured by Colcoat),
Using 57.8 parts of ethanol, 7.9 parts of a 1% nitric acid aqueous solution, and 14.7 parts of pure water, a solid having a SiO ₂ (silicon oxide) solid concentration of 10% and a weight average molecular weight of 1940 was prepared. A mixture of IPA and n-butanol (NBA) (IPA) is finally adjusted so that the SiO ₂ solid content concentration becomes 1.0%.
/ NBA = 3/1).

The transparent 2 formed on the glass substrate
The film properties (visible light transmittance, standard deviation of transmittance, haze value, bottom reflectance / bottom wavelength, surface resistance) of the layer film are shown in Table 1 below.

The above-mentioned bottom reflectance means the minimum reflectance in the reflection spectrum of the low transmittance transparent substrate, and the bottom wavelength means the wavelength at which the reflectance is minimum. FIG. 3 shows the reflection spectrum of the manufactured low-transmittance transparent substrate according to Example 3, and FIG. 4 shows the transmission spectrum.

Comparative Example 1 In Example 1, carbon fine particles [MA-7, manufactured by Mitsubishi Kasei Co., Ltd.] were used instead of titanium nitride fine particles, and carbon fine particles having a dispersed particle diameter of 40 nm were dispersed. Binder-containing coating liquid (carbon: 0.30%, SiO2: 0.60%,
Water: 0.60%, EA: 4.21%, IPA: 88.6
(6%, PGM: 5.0%) in the same manner as in Example 1 except that a glass substrate with a low transmittance transparent layer containing fine carbon particles and a binder matrix, that is, a low transmittance according to Comparative Example 1 was prepared. A highly transparent substrate was obtained.

The film characteristics (visible light transmittance, standard deviation of transmittance, haze value) of the low transmittance transparent layer formed on the glass substrate are shown in Table 1 below. FIG. 5 shows the transmission spectrum of the manufactured low transmittance transparent layer according to Comparative Example 1.
Shown in

Comparative Example 2 In Example 3, carbon fine particles [MA-7, manufactured by Mitsubishi Kasei Co., Ltd.] were used in place of the titanium nitride fine particles and the ATO fine particles.
Coating solution for forming a low transmittance transparent layer containing carbon fine particles in which 0 nm carbon fine particles are dispersed (carbon: 0.32%, E
A: 56.78%, IPA: 11.95%, PGM: 3
0.0%) was prepared in the same manner as in Example 3, except that a low transmittance transparent layer containing carbon fine particles and a transparent coat layer composed of a silicate film containing silicon oxide as a main component were used. A glass substrate with a transparent two-layer film, that is, a low-transmittance transparent substrate according to Comparative Example 2 was obtained.

Then, the transparent 2 formed on the glass substrate
The film properties (visible light transmittance, standard deviation of transmittance, haze value, bottom reflectance / bottom wavelength, surface resistance) of the layer film are shown in Table 1 below. FIG. 6 shows a reflection profile of the manufactured low-transmittance transparent substrate according to Comparative Example 2, and FIG. 7 shows a transmission profile thereof.

[0087]

[Table 1] [Film property evaluation] Visible light transmittance and standard deviation of transmittance of low transmittance transparent base materials according to Examples in which titanium nitride fine particles alone or a mixture of titanium nitride fine particles and carbon fine particles were applied as black pigment fine particles. , Haze value, etc.
It shows almost the same value as the low transmittance transparent base material according to each comparative example in which carbon fine particles are applied as black pigment fine particles, and the hiding power (coloring power) of the titanium nitride fine particles is (Coloring power).

Further, the transmittance profile of the low transmittance transparent substrate according to each example (see FIGS. 1, 2 and 4).
Is flat compared to the transmittance profile of the low transmittance transparent base material according to each comparative example (see FIGS. 5 and 7), and there is no decrease on the short wavelength side of visible light. It is also confirmed that the composition is suitable for a low transmittance transparent substrate.

Further, the reflectance profile of the low transmittance transparent substrate according to Example 3 (see FIG. 3) and the reflectance profile of the low transmittance transparent substrate according to Comparative Example 2 (see FIG. 6) are shown. As is clear from the comparison, it is confirmed that the reflection characteristics of the low-transmittance transparent substrate according to Example 3 including the transparent two-layer film are excellent as in Comparative Example 2.

[Weather Resistance Test] The transparent substrates having low transmittance according to Examples 1 to 3 were immersed in a 10% aqueous saline solution, a 50% aqueous acetic acid solution, and a 5% aqueous ammonia solution for 24 hours to obtain a transparent substrate (glass substrate). The transmittance and appearance of the film provided thereon were examined, but no change was observed.

[Film Strength Test] The low transmittance transparent base materials according to Examples 1 to 3 were evaluated by a pencil hardness test (load 1 kg), and the results are shown in Table 2 below.

[0092]

[Table 2]

[0093]

According to the low transmittance transparent substrate according to the first, third, fourth and eighth aspects of the present invention, a CRT has a flat transmission spectrum and excellent mechanical strength and weather resistance.
When applied to the front panel of a display device, the display device has effects such as making the display screen easier to see.

Similarly, according to the low transmittance transparent substrate according to the second, third, fourth and eighth aspects of the present invention, it has a low reflectance, a flat transmission spectrum, and a low mechanical strength and weather resistance. When applied to the front panel of a display device such as a CRT,
This has the effect of making the display screen easier to see.

Further, according to the low transmittance transparent substrate according to the fifth and sixth aspects of the present invention, since the conductive oxide fine particles are contained in the low transmittance transparent layer, an antistatic / electric field shield is provided. It has the effect that functions can be added.

According to the method for producing a low-transmittance transparent substrate according to the present invention, the low-transparency transparent substrate according to the first to eighth aspects can be produced at low cost. Having.

Further, according to the display device of the present invention, since the low transmittance transparent base material according to any one of the first to eighth aspects is incorporated as a front plate, a display screen can be displayed. This has the effect of making it easy to see and also having an antistatic and electric field shielding function.

[Brief description of the drawings]

FIG. 1 is a graph showing a transmission spectrum of a low-transmittance transparent substrate according to Example 1.

FIG. 2 is a graph showing a transmission spectrum of a low transmittance transparent substrate according to Example 2.

FIG. 3 is a graph showing a reflection spectrum of a low transmittance transparent layer according to Example 3.

FIG. 4 is a graph showing a transmission spectrum of a low transmittance transparent layer according to Example 3.

FIG. 5 is a graph showing a transmission spectrum of a low transmittance transparent layer according to Comparative Example 1.

FIG. 6 is a graph showing a reflection spectrum of a low transmittance transparent layer according to Comparative Example 2.

FIG. 7 is a graph showing a transmission spectrum of a low transmittance transparent layer according to Comparative Example 2.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G09F 9/00 309 G02B 1/10 Z H04N 5/72 A F term (Reference) 2H042 AA06 AA11 AA27 2K009 AA05 AA12 BB02 BB11 CC01 CC02 CC03 DD02 DD06 EE00 EE03 4G059 AA01 AA07 AC04 AC12 EA01 EA02 EA03 EA05 EA11 EA12 EA18 EB05 GA01 GA04 GA12 5C058 AA01 BA08 DA01 DA03 DA08 5G435 AA01 AA02 HB17A12AA12 GG

Claims (18)

[Claims] 1. A low-transmittance transparent substrate comprising a transparent substrate and a low-transmittance transparent layer formed on the transparent substrate, wherein the low-transmittance transparent layer has a black pigment having an average particle size of 5 to 150 nm. Fine particles and a binder matrix are the main components, and the black pigment fine particles are composed of titanium nitride fine particles alone or a mixture of titanium nitride fine particles and carbon fine particles, and the low-transmittance transparent layer has a visible light transmittance of 20%. ~ 80% and visible light wavelength range (380-78).
(0 nm), wherein the standard deviation of the transmittance of the low transmittance transparent layer at each wavelength of 5 nm is 0 to 6%. 2. A low-transmittance transparent base material comprising a transparent substrate and a two-layer transparent film formed of a low-transmittance transparent layer and a transparent coat layer sequentially formed on the transparent substrate. The layer is mainly composed of black pigment fine particles having an average particle diameter of 5 to 150 nm and a binder matrix, and the black pigment fine particles are composed of titanium nitride fine particles alone or a mixture of titanium nitride fine particles and carbon fine particles, and the low transmittance The reflectance at which the reflection spectrum in the visible light region of the transparent substrate is minimized is 3% or less, and
The transparent bilayer film has a visible light transmittance of 20 to 80% and a standard deviation of the transmittance of the transparent bilayer film at each wavelength of 5 nm in the visible light wavelength range (380 to 780 nm) of 0.
And a low transmittance transparent base material characterized in that the base material content is about 6%. 3. The method according to claim 1, wherein the mixing ratio in the mixture of the titanium nitride fine particles and the carbon fine particles is set to not more than 200 parts by weight of the carbon fine particles with respect to 100 parts by weight of the titanium nitride fine particles. The low-transmittance transparent substrate according to the above. 4. The mixing ratio of the black pigment fine particles and the binder matrix in the low transmittance transparent layer is such that the binder matrix 10
The low transmittance transparent substrate according to claim 1 or 2, wherein the amount is set to 0 to 1100 parts by weight. 5. The low-transmittance transparent layer has an average particle size of 10-15.
0 nm conductive oxide fine particles are contained, and the compounding ratio of the conductive oxide fine particles is set to 50 to 1000 parts by weight based on 100 parts by weight of the black pigment fine particles, and the low transmittance transparent layer is used. Has a surface resistance of 10 ⁴ to 10 ¹¹ Ω
2. The low-transmittance transparent substrate according to claim 1, wherein 6. The transparent layer having a low transmittance has an average particle size of 10-15.
0 nm conductive oxide fine particles are contained, and the compounding ratio of the conductive oxide fine particles is set to 50 to 1000 parts by weight with respect to 100 parts by weight of the black pigment fine particles, and the transparent two-layer film is Surface resistance is 10 ⁴ to 10 ¹¹ Ω / □
3. The low-transmittance transparent substrate according to claim 2, wherein: 7. The low transmittance transparent material according to claim 5, wherein said conductive oxide fine particles are at least one kind of fine particles selected from indium tin oxide fine particles or tin antimony oxide fine particles. Base material. 8. The low transmittance transparent substrate according to claim 1, wherein the binder matrix of the low transmittance transparent layer and the transparent coat layer contain silicon oxide as a main component. . 9. The method for producing a low-transmittance transparent substrate according to claim 1, wherein the solvent has a mean particle diameter of 5 which is composed of titanium nitride fine particles alone or a mixture of carbon fine particles and titanium nitride fine particles dispersed in the solvent. A method for producing a low-transmittance transparent base material, comprising applying a coating liquid mainly containing fine particles of black pigment of about 150 nm and an inorganic binder to a transparent substrate, followed by heat treatment. 10. The composition according to claim 1, wherein the mixing ratio of the black pigment fine particles and the inorganic binder in the coating liquid is set to 100 to 1100 parts by weight of the inorganic binder with respect to 100 parts by weight of the black pigment fine particles. 10. The method for producing a low-transmittance transparent substrate according to item 9. 11. An average particle diameter of 10 to 150 nm in the coating liquid.
The conductive oxide fine particles are contained, and the compounding ratio of the conductive oxide fine particles is set to 50 to 1000 parts by weight with respect to 100 parts by weight of the black pigment fine particles. 11. The method for producing a low-transmittance transparent substrate according to item 10. 12. The method for producing a transparent substrate having a low transmittance according to claim 2, wherein the average particle diameter is composed of a solvent and titanium nitride fine particles alone or a mixture of titanium nitride fine particles and carbon fine particles dispersed in the solvent. A low-transmittance transparent base material, which is obtained by applying a coating liquid containing 5-150 nm fine particles of black pigment as a main component on a transparent substrate, and then applying a coating liquid for forming a transparent coat layer, followed by heat treatment. Manufacturing method. 13. An average particle diameter of 10 to 150 nm in the coating liquid.
13. The conductive oxide fine particles of the above, and the compounding ratio of the conductive oxide fine particles is set to 50 to 1000 parts by weight based on 100 parts by weight of the black pigment fine particles. For producing a low transmittance transparent base material. 14. The method according to claim 12, wherein an inorganic binder is contained in the coating liquid. 15. The low transmittance transparent material according to claim 11, wherein said conductive oxide fine particles are at least one kind of fine particles selected from indium tin oxide fine particles or tin antimony oxide fine particles. Production method of conductive base material. 16. The mixing ratio of the titanium nitride fine particles and the carbon fine particles in the mixture of titanium nitride fine particles
The method for producing a low-transmittance transparent substrate according to any one of claims 9 to 15, wherein the carbon fine particles are set to 200 parts by weight or less based on parts by weight. 17. The method according to claim 12, wherein the coating liquid for forming the transparent coat layer and the inorganic binder of the coating liquid are mainly composed of silica sol. 18. A display device comprising a device main body and a front plate disposed on the front side thereof, wherein the low transmittance transparent base material according to claim 1 is used as the front plate. A display device, wherein the display device is incorporated with the transparent layer or the transparent two-layer film side facing the outside.