JP3262248B2 - Anti-reflective coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film for preventing or reducing reflection. INDUSTRIAL APPLICABILITY The antireflection film of the present invention is useful for preventing reflection of a display screen such as a cathode ray tube and a liquid crystal display plate, and for preventing reflection of a transparent plate having a problem of reflection of external light such as a front glass of an instrument panel and an automobile glass.

[0002]

2. Description of the Related Art Display devices such as a cathode ray tube and a liquid crystal display panel are widely used in industrial and consumer fields, and the image quality is remarkably improved. Often degrades the image quality. Also, the visibility of instruments, front panels of watches, windshields of automobiles, and the like is impaired by the reflection of external light, which is a problem.

In order to solve the above problems, it is effective to lower the reflectance of the surface. As a means for achieving this, a method of laminating transparent films having different refractive indexes on the substrate surface has been adopted. I have. However, in order to obtain a sufficient anti-reflection effect, it is necessary to form a multilayer film of at least three or more layers, and such multilayer film has poor productivity and high manufacturing cost is preventing its spread. .

Japanese Patent Application Laid-Open No. 5-203804 discloses that a first transparent film formed on a substrate and a second transparent film formed thereon further contain an appropriate dye in the first transparent film. By doing so, an antireflection film is described which is configured so that the wavelength at which the spectral transmittance becomes minimum and the wavelength at which the spectral reflectance becomes minimum in the visible region are substantially matched, and thus the antireflection effect is obtained over a wider band. ing.
However, since the antireflection film strongly expresses interference light of a specific wavelength, a specific color appears strongly in the eyes, and eyes of the display are likely to be tired if the display is viewed for a long time.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the conventional antireflection transparent film, to have good antireflection ability, to be excellent in productivity and to be low in manufacturing cost.
An object of the present invention is to provide an anti-reflection film capable of obtaining light close to natural light that is easy on the eyes without strong interference light having a specific wavelength.

[0006]

The purpose of the Means for Solving the Problems] was formed in close contact on the surface of the transparent base material bending modulus N ₁ is 1.45 to 2.
The first transparent film having a range of 10 and the refractive index N1 of the _first transparent film, which is formed in close contact with the first transparent film, are 0.1.
Made from the second transparent film having a low refractive index N ₂ or more, the thickness D ₁ of the first transparent film (nm) is _{(0.25 · L 1 / N 1} ) -100 ≦ D 1 ≦ (0. 25 ・
L ₁ / N ₁ ) +100, and the thickness D ₂ (nm) of the _second transparent film is (0.25 · L ₁ / N ₂ ) −100 ≦ D ₂ ≦ (0.25 ·
L ₁ / N ₂ ) +100, and at least a light absorbing agent is contained in the first transparent film, and the main absorption wavelength L ₂ (nm) of the light absorbing agent is L ₁ + 70 ≦ L ₂ (each of the above. Where L ₁ is a design wavelength in the range of 400 to 800 nm).

[0007]

In the antireflection film of the present invention, the first transparent film and the second transparent film have the above-mentioned thicknesses D ₁ and D ₂ , respectively.
In addition, at least the first transparent film contains a light absorbing agent, and the main absorption wavelength L ₂ (nm) of the light absorbing agent in the entire antireflection film is L
It is essential that ₁ + 70 ≦ L ₂ .

In the anti-reflection coating, the surface of a transparent substrate such as glass or plastic has a refractive index of 1.45 to 2.10.
And a second transparent film having a refractive index lower than the refractive index of the first transparent film by 0.1 or more is formed on the first transparent film. ,
A certain anti-reflection effect can be obtained. However, the spectrum of the reflected light has a strong wavelength dependence, and not only the reflected light is colored, but also the antireflection film effect cannot be obtained over a wide range of visible light. Therefore, sufficient antireflection or reduction characteristics cannot be achieved visually.

[0010] Refractive index of the first transparent film and the second transparent film
In addition to selecting the thickness and the film thickness as described above, if at least the first transparent film contains a light absorbing agent, the interface between the base material and the first transparent film, the first transparent film and the second The balance between the light reflected from the interface with the transparent film and the surface of the second transparent film is adjusted, and as a result, the reflection spectrum is improved and the reflectance is reduced.

It is important that the light absorber is incorporated in at least the first transparent film in order to avoid coloring transmitted light as much as possible and to obtain a sufficient antireflection effect. Light absorber first
When blending both the transparent film and the second transparent film, the first
Depending on the combination of the transparent film and the second transparent film, a sufficient anti-reflection effect may not be obtained simply by coloring the transmitted light of the film. In particular, it has been found that when the light absorption of the second transparent film is higher than that of the first transparent film, the antireflection effect is rather reduced. Therefore, the light absorbing agent should be blended only in the first transparent film, or be contained in both transparent films as long as the light absorption of the second transparent film is not higher than that of the first transparent film. Is preferred.

It is preferable that the maximum absorption wavelength of the light absorber incorporated in the transparent film is selected in consideration of the thicknesses of the first and second transparent films. That is, the first transparent film and the second
When the thickness (D ₁ and D ₂ ) (nm) of the transparent film is within a certain range around (0.25 · L / N) (nm), the light absorbing agent is not included. In this case, the graph showing the relationship between the wavelength and the reflectance is V-shaped (when there is no light absorbing agent) (see FIG. 1A), so that the visible light wavelength L (corresponding to the V-shaped bottom point) It is preferable to mix a light absorber that mainly absorbs visible light other than (nm), and in particular, a wavelength range of 500 to 600 (n
As a result of performing simulation in consideration of the modulation of light energy in order to reduce the reflectance in m), the light absorber having the maximum absorption wavelength outside this wavelength region of 500 to 600 (nm) improves the V-shaped spectrum. Was found to be particularly effective and very preferable. The reflectivity of the film containing such a light absorbing agent is a curve with an expanded bottom as shown in FIG.

Therefore, in the antireflection film of the present invention,
The main absorption wavelength L ₂ (n
The type and the mixing ratio of the light absorber are selected so that m) satisfies L ₁ + 70 ≦ L ₂ . Once this requirement is met,
Interference light of a specific wavelength does not appear strongly, and light close to natural light that is easy on the eyes is obtained.

[0014] In particular, the main absorption wavelength _{L 2} is 570~740nm
When phthalocyanine blue is used as a light absorber, the effect is more remarkably observed at an optical absorption of about 0.009 abs, and the effect is remarkable at an absorbance of 0.022 abs or more. Become. Particularly preferred main absorption wavelength _{L 2} is 590-7
00 nm.

[0015]

[0016]

As a material for forming the first and second transparent films, a material which has a refractive index and a maximum absorption wavelength λ satisfying the above requirements and can form a transparent film is used. Examples of such a material include inorganic compounds such as silica compounds, porous silica, titanium compounds, tin compounds, indium compounds, and zirconium compounds, and organic materials such as acrylic resins, polyester resins, vinyl chloride resins, and epoxy resins. No. These can be used alone or in combination of two or more.

Light absorbers include, for example, monoazo pigment, quinacridone, iron oxide yellow, disazo pigment, phthalocyanine green, phthalocyanine blue, cyanine blue, flavanthrone yellow, dianthraquinolyl red, indanthrone blue, thiophene Indigo bordeaux, perinone orange, perylene scarlet, perylene red 178, perylene maroon, dioxazine violet, isoindolinone yellow, quinophthalone yellow, isoindolin yellow,
Nickel Nitroso Yellow, Madder Lake, Copper Azomethine Yellow, Aniline Black, Alkaline Blue, Zinc Flower,
Titanium oxide, red iron oxide, chrome oxide, iron black, titanium yellow,
Cobalt blue, cerulean blue, cobalt green, alumina white, viridian, cadmium yellow, cadmium red, vermilion, lithopone, graphite, molybdate orange, zinc chromate, calcium sulfate, barium sulfate, calcium carbonate, lead white, ultramarine, manganese Violet, cobalt violet, emerald green,
Navy blue, carbon black, organic and inorganic pigments such as metal powder, and azo dyes, anthraquinone dyes, indigoid dyes, phthalocyanine dyes, carbonium dyes,
Dyes such as a quinone imine dye, a methine dye, a quinoline dye, a nitro dye, a nitroso dye, a benzoquinone dye, a naphthoquinone dye, a naphthalimide dye, and a verinone dye are exemplified. These light absorbers can be used alone or in combination of two or more.

The absorbance A of the light absorber is represented by the following formula. A = log ₁₀ (I ₀ / I) = εCD (where I ₀ : incident light, I: transmitted light, C: color density, D:
Optical distance (film thickness), ε: molar extinction coefficient) In the present invention, a light absorber having a molar extinction coefficient ε> 10 ⁴ is generally used, and the absorbance A ₁ of the first transparent film is 0.1.
0005-3abs. And the absorbance A2 of the _second transparent film is 3 abs. It is desirable that: If these requirements are not met, the transparency or the antireflection effect will be reduced.

Various materials can be added to the first and second transparent films as long as the object of the present invention is achieved. For example, when at least one of the first and second transparent films uses at least one of antimony-doped tin oxide powder or tin-doped indium oxide powder as the transparent film forming material, the antistatic property is excellent and the visible light is improved. And a transparent film having a sufficiently high density can be obtained. In particular, this advantage is greater when a film is formed by a coating method.

The second transparent film preferably contains porous silica, particularly preferably porous silica having an average particle diameter of 0.3 to 100 nm and a refractive index of 1.2 to 1.4. By including such porous silica, a second material having a low refractive index having an effect of reducing the reflectance is provided.
Is obtained. The particle diameters of the material particles and the light absorber particles constituting the first and second transparent films are not particularly limited as long as they are equal to or less than the film thickness, but the light scattering of visible light is suppressed and the density is sufficiently high. Particle size is 100n to obtain film
m or less. As an example, applying tin oxide particles having various particle diameters doped with antimony,
Table 1 shows the results of preparing a film without using a binder and examining the transparency and the refractive index.

[0022]

[Table 1]

Examples of the substrate on which the antireflection film of the present invention is formed include a display such as a television cathode ray tube and a liquid crystal display panel, and a front panel such as an instrument and a clock. Made of plastic.
As a method of forming the transparent film of the present invention, various methods conventionally used can be employed. That is,
A sputtering method, a vapor deposition method, a coating method, and the like are employed. Among these, a coating method that is inexpensive and easily forms a film is preferable, and a spray method, a spin coating method, a dipping method, a gravure method, and the like are particularly preferable. Hardening conditions (heating temperature, time) at the time of film formation are selected by a usual coating technique.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to embodiments. The properties of the transparent material laminates obtained in each of the examples and comparative examples were measured as follows. (1) The surface resistivity is Model HC manufactured by Mitsubishi Yuka Co., Ltd.
It measured using the P-HT250 four-terminal surface resistance meter.

(2) Haze and total light transmittance were measured using a Model TC-HIIIDP haze meter manufactured by Tokyo Denshoku Co., Ltd. (3) The surface reflectance was measured by a spectrophotometer using a specular reflection jig having an incident angle of 5 degrees. (4) The adhesiveness was determined according to MIL-C-675C by Eraser No. 1 manufactured by Lion Corporation. 50 and reciprocated 20 times while applying a load of 1 kgf and rubbing the surface,
The occurrence of surface damage was visually observed and evaluated.

Example 1 (1) High refractive index film containing light absorber (solid weight ratio: blue pigment / titanium oxide / antimony-doped tin oxide = 5/3)
0/65) Forming coating (a) was prepared as follows.
Antimony-doped tin oxide fine powder (Sumitomo Cement)
0.59 g and blue pigment fine powder (manufactured by Toyo Ink Manufacturing Co., Ltd .:
0.05 g of trademark CYANINE BLUE BNRS)
After mixing 0.96 g of titanium isopropoxide with a solution consisting of 53.98 g of ethanol, 40 g of ethyl cellosolve, 4 g of water, 0.08 g of hydrochloric acid and 0.34 g of acetylacetone, an ultrasonic homogenizer (manufactured by Central Science Trading Co .; (Fire 450) for 10 minutes to obtain a uniform dispersion.

(2) A coating material (b) for forming a low refractive index film was prepared as follows. 0.8 g of tetraethoxysilane, 0.01 g of hydrochloric acid, 98.39 g of ethyl alcohol and 0.1 g of water.
8 g were mixed to form a uniform solution. (3) Production of Laminate The above-mentioned paint (a) was placed on a glass substrate at a surface temperature of 40 ° C.
Is applied by spin coating, and heated with 50 ° C warm air.
Dried for minutes. A light absorbing agent-containing high refractive index film having a thickness of 0.1 μm was formed. Next, at 40 ° C., a coating (b)
Was applied by spin coating, dried by warm air at 50 ° C., and baked at 160 ° C. for 20 minutes to form a low-refractive-index film having a thickness of 0.1 μm. The evaluation results is shown in Table 2, the reflection spectrum of the anti-reflection film 2
Shown in

Example 2 The same operation as in Example 1 was performed. However, the weight ratio of the solid content in the coating material for forming a high refractive index film containing a light absorber is expressed by a ratio of blue pigment (0.04 g) / black pigment (carbon black manufactured by Mitsubishi Kasei Corporation, trademark MA100, 0.04 g) / titanium oxide. Product (titanium isopropoxide, 0.68 g)
/ Antimony-doped tin oxide (0.83 g) = 4/4/1
7/75, and the amount of acetylacetone in the paint was changed to 0.24 g, and the amount of ethanol was changed to 54.08 g. The evaluation results is shown in Table 2 shows the reflection spectrum of the anti-reflection film in Fig.

Comparative Example 1 The same operation as in Example 1 was performed. However, the light-absorbing agent was not added to the coating material for forming a high-refractive-index film, and the solid content weight ratio in this coating material was determined to be titanium oxide (titanium isopropoxide 0.76 g) / antimony-doped tin oxide (0.89 g).
= 19/81, the amount of acetylacetone in the paint was changed to 0.27 g, and the amount of ethanol was 54.0 g.
Changed to The evaluation results is shown in Table 2 shows the reflection spectrum of the anti-reflection film in Fig.

Example 3 The same operation as in Example 1 was performed. However, the weight ratio of the solid content in the coating material for forming a high refractive index film containing a light absorber was as follows: blue pigment (0.054 g) / black pigment (0.066 g) / antimony-doped tin oxide (1.88 g) = 2.7 / 3.3
/ 94, and the coating material for forming a high refractive index film was prepared as follows. 1.88 g of antimony-doped tin oxide fine powder (manufactured by Sumitomo Cement Co., Ltd.), 0.066 g of black pigment fine powder (carbon black: MA-100, manufactured by Mitsubishi Kasei Co., Ltd.) and blue pigment fine powder (manufactured by Toyo Ink Manufacturing Co., Ltd .: CYANI
NE BLUE BNRS) 0.054 g with water 97.9
9 g and a surfactant (silicone surfactant, trademark: L-
After mixing with a solution consisting of 0.01 g), the mixture was treated with an ultrasonic homogenizer for 10 minutes,
A uniform dispersion was obtained. Further, a coating material for forming a low refractive index film was prepared as follows. That is, 0.54 g of tetramethoxysilane and 0.3 of porous silica (manufactured by Sumitomo Cement Co., Ltd.)
6 g, 0.6 g of 0.1 N hydrochloric acid, and ethyl alcohol.
5 g were mixed to obtain a uniform dispersion. The evaluation results is shown in Table 2 shows the reflection spectrum of the anti-reflection film in Fig.

Example 4 The same operation as in Example 3 was performed. However, the coating material for forming a low refractive index film was prepared as follows. 0.8 g of tetramethoxysilane, 0.2 g of porous silica and 0.1N hydrochloric acid 0.1 g.
9 g and 98.1 g of ethyl alcohol were mixed to form a uniform dispersion. Table 2 shows the evaluation results, and FIG. 6 shows the reflection spectrum of the antireflection film.

Example 5 The same operation as in Example 3 was performed. However, the coating material for forming a low refractive index containing a light absorber was prepared as follows. 0.76 g of tetramexylane, 0.2 g of porous silica, and 0.04 g of yellow paint (trademark: ASTRAZON YELLOW, manufactured by Bayer AG Leverkusen) and 0.1
0.9 g of N hydrochloric acid and 98.1 g of ethyl alcohol were mixed to form a uniform dispersion. Table 2 shows the evaluation results, and FIG. 7 shows the reflection spectrum of the antireflection film.

[0033]

[Table 2]

[0034]

The anti-reflection film of the present invention has good anti-reflection ability, has good productivity, and can provide natural light which is easy on eyes and is close to natural light.

[Brief description of the drawings]

FIG. 1A is a graph showing the relationship between the wavelength and the reflectance in a transparent film containing no light absorber, and FIG. 1B is a graph showing the relationship between the wavelength and the reflectance in a transparent film containing a light absorber. It is a graph shown.

FIG. 2 is a reflection spectrum of an example of the antireflection film of the present invention.

FIG. 3 is a reflection spectrum of another example of the antireflection film of the present invention.

FIG. 4 is a reflection spectrum of an antireflection film of a comparative example.

FIG. 5 is a reflection spectrum of another example of the antireflection film of the present invention.

FIG. 6 is a reflection spectrum of still another example of the antireflection film of the present invention.

FIG. 7 is a reflection spectrum of still another example of the antireflection film of the present invention.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Akira Yazawa 585 Tomicho, Funabashi-shi, Chiba Sumitomo Cement Co., Ltd. (56) References JP-A-5-203804 (JP, A) JP-A-6-208003 (JP, A) JP-A-58-46301 (JP, A) JP-A-4-203 334853 (JP, A) JP-A-5-113505 (JP, A) JP-A-4-67545 (JP, A) JP-A-62-298301 (JP, A) JP-A-4-345737 (JP, A)

Claims (9)

(57) [Claims] 1. A a first transparent film tortuosity N ₁ formed in close contact on the surface of the transparent substrate is in the range of 1.45 to 2.10, in close contact with the first transparent film formed Te, made from a second transparent film having a low refractive index N ₂ 0.1 or more than the refractive index N ₁ of the first transparent film, the thickness D ₁ of the first transparent film (nm)
Is (0.25 · L ₁ / N ₁ ) -100 ≦ D ₁ ≦ (0.25 ·
L ₁ / N ₁ ) +100, and the thickness D ₂ (nm) of the _second transparent film is (0.25 · L ₁ / N ₂ ) −100 ≦ D ₂ ≦ (0.25 ·
L ₁ / N ₂ ) +100, and at least a light absorbing agent is contained in the first transparent film, and the main absorption wavelength L ₂ (nm) of the light absorbing agent is L ₁ + 70 ≦ L ₂ (each of the above. Wherein L ₁ in the formula is a design wavelength in the range of 400 to 800 nm). 2. The antireflection film according to claim 1, wherein the main absorption wavelength L ₂ (nm) of the light absorbing agent is 570 ≦ L ₂ ≦ 740. 3. The first and second transparent films are selected from silica compounds, porous silica, titanium compounds, tin compounds, indium compounds, zirconium compounds, acrylic resins, polyester resins, vinyl chloride resins, and epoxy resins. The antireflection film according to claim 1, wherein the antireflection film is configured to include at least one material. 4. The anti-reflection film according to claim 3, wherein the second transparent film contains porous silica. 5. The porous silica has an average particle size of 0.3 to 10.
The antireflection film according to claim 4, wherein the antireflection film has a thickness of 0 nm and a refractive index of 1.2 to 1.4. 6. The antireflection method according to claim 1, wherein at least one of the first and second transparent films contains at least one of tin oxide powder doped with antimony and indium oxide powder doped with tin. film. 7. The first and second transparent films have a particle size of 100 n.
The antireflection film according to any one of claims 1 to 6, wherein the antireflection film is made of a material of m or less. 8. The antireflection film according to claim 1, wherein the light absorber contains at least one selected from the group consisting of organic pigments, inorganic pigments and dyes. 9. The light absorbing agent is monoazo pigment, quinacridone, iron oxide yellow, disazo pigment, phthalocyanine green, phthalocyanine blue, cyanine blue, flavanthrone yellow, dianthraquinolyl red, indanthrone blue, or thioindigo bordeaux. , Perinone orange, Perylene scarlet, Perylene red 178, Perylene maroon, Dioxosazine violet, Isoindolinone yellow, Quinophthalone yellow, Isoindolin yellow, Nickel nitroso yellow, Madder lake, Copper azomethine yellow, Aniline black, Alkaline blue, Zinc flower , Titanium oxide, red iron oxide, chrome oxide, iron black, titanium yellow, cobalt blue, cerulean blue, cobalt green, alumina white, viridian, Cadmium yellow, cadmium red, vermilion, lithopone, graphite, molybdate orange, zinc chromate, calcium sulfate, barium sulfate, calcium carbonate, lead white, ultramarine, manganese violet, cobalt violet, emerald green, navy blue, carbon black, metal Powder, azo dye, anthraquinone dye, indigoid dye, phthalocyanine dye, carbonium dye, quinone imine dye, methine dye, quinoline dye, nitro dye, nitroso dye, benzoquinone dye, naphthoquinone dye, naphthalimide dye, verinone dye The antireflection film according to claim 1, comprising at least one kind.