JPH0772305A - Antireflection film and antireflection member - Google Patents

Abstract

PURPOSE:To provide the antireflection film and antireflection member having an excellent antireflection effect even with a number of superposition of two layers for light having a wavelength region, excellent mass productivity, excellent contamination resistance and excellent property to sustain the antireflection effect. CONSTITUTION:This antireflection film consists of at least the superposition of layers consists of a fluorine-containing layer (1) having an optical film thickness of 0.2 to 0.3 times the central wavelength in the wavelength region desired for antireflection and a Y2O3 layer (2) of 0.45 to 0.55 times the wavelength described above and has this fluorine-contained layer on an incident side surface. The fluorine-containing layer consists of a fluorine-contained compd. having thickness 100mum, transmittance >=80%, fluorine atom content >=60wt.% and refractive index <=1.40. This antireflection member has such antireflection film on at least one side of a transparent base material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection film excellent in mass productivity and stain resistance and suitable for antireflection of various visual recognition devices and the like, and an antireflection member thereof.

[0002]

2. Description of the Related Art Conventionally, as an antireflection film for light having a wavelength range such as visible light, there has been known a multilayer film in which transparent thin films such as metal oxides are superposed. Such a multilayer structure can effectively prevent reflection of light having a single wavelength with a single-layer film, but cannot effectively prevent reflection of light having a wavelength range. It is effective in preventing reflection in the area. Therefore, for example, wavelength 4
In order to prevent reflection in the visible light region of 00 to 700 nm, it is general that the incident side surface is made up of three or more superposed layers formed of metal oxide layers such as SiO ₂ , and in the case of two layers, it is high. It has been said that accurate antireflection cannot be achieved.

However, in order to form an antireflection film having a multi-layered structure, an advanced technique is required to control the film thickness of the thin films with high precision in consideration of the refractive index of each thin film to be superposed, and therefore the number of superposed films is increased by one layer. This alone requires a lot of time and labor, and there is a problem that the manufacturing efficiency is greatly reduced. Further, there is a problem that the metal oxide layer on the incident side surface is easily contaminated with fingerprints or the like, and the antireflection effect is significantly reduced due to the contamination.

[0004]

DISCLOSURE OF THE INVENTION The present invention has an excellent antireflection effect even when the number of superposed layers is two with respect to light having a wavelength range and is excellent in mass producibility, and is also excellent in stain resistance and antireflection effect. An object of the present invention is to obtain an antireflection film and an antireflection member having excellent durability.

[0005]

According to the present invention, the optical film thickness of the central wavelength of 0.2 to 0.
The fluorine-containing layer has a thickness of at least an overlapping layer of a 3-fold fluorine-containing layer and a 0.45-0.55-fold Y ₂ O ₃ layer, and has the fluorine-containing layer on the incident side surface. 80% transmittance at 100 μm, fluorine atom content 6
An antireflection film comprising a fluorine-containing compound having a refractive index of 0% by weight or more and a refractive index of 1.40 or less, and an antireflection member having the antireflection film on at least one side of a transparent substrate. Is provided.

[0006]

By using the fluorine-containing layer having the above-mentioned structure as a layer that overlaps with the Y ₂ O ₃ layer having the incident side surface, the wavelength range can be improved even when the antireflection film is composed of such two layers and is advantageous for mass production. It exhibits a satisfactory antireflection effect with respect to its own light. By the way, in the visible light range of 400 to 700 nm, it is usually 9
An average transmittance of 8% or more can be achieved. Further, by having a fluorine-containing layer on the incident side surface, it is excellent in water repellency, oil repellency and the like and is unlikely to be contaminated, and the contamination is easily removed and the contamination resistance is excellent, and the antireflection effect can be maintained for a long period of time.

[0007]

EXAMPLES The antireflection film of the present invention comprises at least a layer superposed with a Y ₂ O ₃ layer having a special fluorine-containing layer on the incident side surface. An example thereof is shown in FIG. Reference numeral 1 is a fluorine-containing layer, and 2 is a Y ₂ O ₃ layer.

In the present invention, the fluorine-containing layer forms the incident side surface of the antireflection film as described above, and has an optical film thickness 0.2 to 0.3 times that of the center wavelength in the wavelength range for antireflection purposes. It is said that If the thickness is out of the above range, it becomes difficult to achieve a satisfactory low reflectance. The optical film thickness is defined as the product of the refractive index and the thickness.

The formation of the fluorine-containing layer has a thickness of 100.
It can be carried out using a fluorine-containing compound having a transmittance of 80% or more in the case of μm, a fluorine atom content of 60% by weight or more, and a refractive index of 1.40 or less. When the fluorine-containing compound forming the fluorine-containing layer does not satisfy the above conditions, it is difficult to achieve the target low reflectance. A fluorine-containing compound that can be preferably used has a refractive index of 1.36.
It is as follows.

Examples of the fluorine-containing compound that can be used in the present invention include the following. General formula (1): (However, R is a fluorine atom, a hydrogen atom or a monovalent hydrocarbon group, and n is 1 to 40.), and the fluorine-containing compound has a fluorine atom content of 60% by weight or more.

Formula (a): A fluorine-containing compound having a refractive index of 1.38 represented by

In the above general formula (1), a fluorine-containing compound in which all R's are fluorine atoms can be preferably used in the present invention. By the way, if all of R are fluorine atoms and the average n is 9.6, the refractive index is 1.34.
And is soluble in a solvent such as a perfluoro-based solvent represented by the following general formula (2).

General formula (2): (However, n is 2 to 8.)

Further, the fluorine-containing compound represented by the above formula (a) is also soluble in tetrahydrofuran or the like, and in the present invention, the fluorine-containing compound soluble in the solvent is used in a coating method such as a dipping method or a spin coating method. A thin film can be easily formed, which is preferable in terms of mass productivity. In that case, the solution concentration is usually 0.1 to 20% by weight from the viewpoint of film thickness control and the like, but is not limited to this.

In the antireflection film of the present invention, at least the Y ₂ O ₃ layer used for forming the superposed layer has 0.45 to 0.55 based on the central wavelength in the wavelength region for antireflection.
The optical film thickness is doubled. If the thickness is out of the above range, it becomes difficult to achieve a satisfactory low reflectance. The Y ₂ O ₃ layer can be formed by an appropriate method such as a vacuum evaporation method, a sputtering method, or an evaporation method such as an ion plating method.

In the antireflection film of the present invention, Si
It is also possible to improve the transmittance as an antireflection film having three or more layers by superposing known layers made of metal oxides such as O ₂ , ZrO ₂ and Al ₂ O ₃ and magnesium fluoride. In that case, for the layers other than the fluorine-containing layer and the Y ₂ O ₃ layer,
It can be appropriately formed according to the conventional method according to the refractive index, the number of overlapping layers, and the like.

The antireflection film of the present invention can be applied by sequentially forming a predetermined superposed layer on the surface for the purpose of antireflection, or by providing the antireflection film on a substrate such as a film. It can also be applied by a method of forming an antireflection member and attaching it to a surface intended for antireflection. The method applied as an antireflection member has an advantage that it can be easily attached to an existing article such as a display device or attached to a curved surface or a large area surface.

The antireflection member of the present invention has the antireflection film of the present invention on at least one side of the transparent substrate.
An example thereof is shown in FIG. 3 is a transparent substrate. In addition, 4 is an adhesive layer provided as needed.

As the transparent base material, an appropriate material can be used.
Those having excellent transmittance and strength are preferable. Generally, a plate, a film or a sheet made of glass, a plastic such as polyester or triacetyl cellulose is used. Further, optical functional materials such as a polarizing plate and a retardation plate can be used. The thickness can be appropriately determined and is generally 5 mm or less, but the thickness is not limited to this.

Further, a transparent substrate which has been subjected to an appropriate treatment such as a hard coat treatment may be used. The hard coat treatment is intended to reinforce the substrate, especially the surface thereof, and is generally formed of a thermosetting resin such as a silicone resin. Further, it may be a hard coat layer mixed with oxide fine particles such as silica, alumina, titania and zirconia, and conductive fine particles such as tin oxide, indium oxide and antimony oxide. A transparent substrate can be used. The antireflection member can be formed by a method of attaching a superposed layer constituting an antireflection film on one side or both sides of the transparent substrate.

The antireflection member of the present invention may be provided with an adhesive layer for the purpose of adhering to the object of application. The adhesive layer to be provided preferably has a refractive index difference of ± 5% or less of the transparent substrate from the viewpoint of preventing reduction of transmittance. For forming the adhesive layer, an appropriate adhesive such as an acrylic adhesive, a rubber adhesive, a silicone adhesive or a hot melt adhesive can be used. Those having excellent transparency and weather resistance are preferable. The attachment of the adhesive layer may be performed by an appropriate method such as a coating method or a transfer method of the one provided on the separator. When the adhesive layer is a pressure-sensitive adhesive layer, it is preferable to protect the surface with a separator or the like until practical use.

The antireflection film or the antireflection member of the present invention is preferably used for preventing interfacial reflection of various articles such as optical functional materials such as polarizing plates, display devices such as liquid crystal display devices, instruments such as weight scales. You can

Example 1 On one surface of a 500 μm thick triacetyl cellulose film (refractive index 1.49), a Y layer having a thickness of 135 nm was formed by vapor deposition.
_{A 2} O ₃ layer (refractive index of 1.87) is formed on the perfluoro solvent of a fluorine-containing compound in which all R in the general formula (1) are fluorine atoms and n is 9.6 on average. The solution was dip-coated and a 95 nm-thick fluorine-containing layer (refractive index 1.34) was superposed to obtain an antireflection member.

The vapor deposition is carried out by an electron gun system without heating the vapor deposition surface, and the ultimate vacuum is 5 × 1/10 ⁵ Torr and the vapor deposition rate is about 0.5 nm / sec. The dip coating is 1.0 mm / sec. The film thickness was measured by observing a cross section with an electron microscope (the same applies hereinafter). Therefore, the film thickness by dip coating was controlled based on the solution concentration. The perfluoro solvent used is represented by the above general formula (2).

Example 2 Reflection was carried out according to Example 1 except that a fluorine-containing layer (refractive index 1.38) having a thickness of 90 nm was formed using a tetrahydrofuran solution of the fluorine-containing compound represented by the above formula (a). The prevention member was obtained.

Example 3 An Al ₂ O ₃ layer (refractive index 1.62) having a thickness of 85 nm and Y ₂ O having a thickness of 140 nm were formed on one surface of a glass plate (refractive index 1.53) having a thickness of 1 mm by a vapor deposition method. _Three layers (refractive index 1.87) are sequentially formed, and a fluorine-containing layer (refractive index 1.34) having a thickness of 95 nm is superposed on the Y ₂ O ₃ layer to obtain an antireflection member according to Example 1. It was

Comparative Example 1 Instead of the Y ₂ O ₃ layer, a ZrO ₂ film having a thickness of 125 nm (refractive index 2.0
An antireflection member was obtained in the same manner as in Example 1 except that 5) was formed.

Comparative Example 2 Same as Example 1 except that the Y ₂ O ₃ layer was 130 nm thick, and the fluorine-containing layer was replaced with 85 nm thick SiO ₂ (refractive index 1.46). Thus, an antireflection member was obtained.

Comparative Example 3 A polyester film having a thickness of 500 μm (refractive index 1.6
On one surface of 8), by vapor deposition, ZrO ₂ with a thickness of 120 nm (refractive index 2.05) and SiO ₂ with a thickness of 90 nm (refractive index 1.46)
Were sequentially formed to obtain an antireflection member.

Evaluation Test Before Contamination Light having a wavelength of 400 to 700 nm is vertically incident from the antireflection film side of the antireflection members obtained in Examples and Comparative Examples, and the reflectance and the transmittance are measured with a spectrophotometer. The average reflectance and the average transmittance in the visible range were obtained.

After contamination, an acrylic pressure-sensitive adhesive tape was pressure-bonded on the antireflection film and rubbed with an eraser 10 times, and then the adhesive tape was peeled off in a vertical direction vigorously. The average transmittance was determined.

The above results are shown in Table 1.

[Table 1]

It can be seen from Table 1 that the antireflection film of the present invention has an excellent antireflection effect with respect to light in the visible region even in the case of a two-layer structure, shows a practically satisfactory transmittance, and is less likely to be contaminated and reflected. It can be seen that the prevention effect and the durability of the transmittance are excellent.

[0034]

According to the present invention, it is possible to obtain a practical anti-reflection film which exhibits an excellent anti-reflection effect against light having a wavelength range even in the case of a superposed layer composed of two layers and which is practical and excellent in mass productivity. You can Further, it has a fluorine-containing layer on the incident side surface and is less likely to be contaminated, and the contamination is easily removed, and the contamination resistance is excellent and the antireflection effect is durable.

[Brief description of drawings]

FIG. 1 is a sectional view of an example of an antireflection film.

FIG. 2 is a sectional view of an embodiment of an antireflection member.

[Explanation of Codes] 1: Fluorine-containing layer 2: Y ₂ O ₃ layer 3: Transparent base material 4: Adhesive layer

Claims (4)

[Claims] 1. A fluorine-containing layer having an optical film thickness of 0.2 to 0.3 times the center wavelength in the wavelength range for antireflection, and
It is composed of at least a 45-0.55 times Y ₂ O ₃ layer and a fluorine-containing layer on the incident side surface, and the fluorine-containing layer has a transmittance of 80 at a thickness of 100 μm.
%, A fluorine atom content of 60% by weight or more, and a refractive index of 1.40 or less, an antireflection film, characterized by comprising: 2. The fluorine-containing compound forming the fluorine-containing layer has a general formula: (However, R is a fluorine atom, a hydrogen atom or a monovalent hydrocarbon group, and n is 1 to 40.) A solvent-soluble refractive index of 1.36 or less. The antireflection film described. 3. An antireflection member having the antireflection film according to claim 1 on at least one side of a transparent substrate. 4. The antireflection member according to claim 3, which has an adhesive layer having a refractive index difference of ± 5% or less of that of the transparent substrate.