WO2011093484A1

WO2011093484A1 - Hydrophilic low-reflection member

Info

Publication number: WO2011093484A1
Application number: PCT/JP2011/051869
Authority: WO
Inventors: 敏明杉本; 多門坂本; 尚史高信
Original assignee: セントラル硝子株式会社
Priority date: 2010-02-01
Filing date: 2011-01-31
Publication date: 2011-08-04
Also published as: JP2011175252A

Abstract

Disclosed is a hydrophilic low-reflection member which comprises a transparent base and a hydrophilic low-reflection film that is formed on the surface of the transparent base. The hydrophilic low-reflection member is characterized in that the hydrophilic low-reflection film contains fine magnesium fluoride hydroxide particles and at least one metal oxide which serves as a refractive index adjusting material and is selected from the group consisting of tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide and tantalum oxide. The hydrophilic low-reflection member is also characterized by having a refractive index of 1.23-1.41 (inclusive). The hydrophilic low-reflection member has high average transmittance within a wavelength range of 380-2,000 nm (inclusive), comprises the hydrophilic low-reflection film that exhibits high bonding strength to the base, and is provided with excellent weather resistance, good antifouling properties due to hydrophilicity, and an antistatic function.

Description

Hydrophilic low reflection member

The present invention relates to a hydrophilic low reflection member having a hydrophilic low reflection film formed on a transparent substrate.

Background of the Invention

Low reflection members include substrates such as solar cells or electrophotographic photoreceptors, optical materials such as lenses for optical equipment such as still cameras, video cameras, and liquid crystal projectors, image display surfaces such as cathode ray tubes and liquid crystal display devices, and copying. Widely used in projectors, imaging tubes, LED display elements, lighting, organic EL, windows and showcases, reflectors for automobile headlamps, etc. Used.

In a transparent substrate such as glass and plastic, a low reflection coating for preventing light reflection on the substrate surface, that is, an optical thin film (hereinafter referred to as a thin film or film) for low reflection on the substrate surface. ) Has been studied. For example, in a still camera or a video camera, if multiple lens groups are used to correct aberrations and the surface reflection of the lens is not suppressed, the resolution of the image will decrease, and flare and ghost may occur in the image. Become.

Also, in a display device, a showcase, etc., unless the surface reflection of the transparent base material used is suppressed, the reflection of the reflected image will deteriorate the visibility itself.

In addition, when the solar cell is used outdoors, for example, when it is installed on the roof of a building, etc., the solar cell is always exposed, so the solar cell front surface is provided with a solar cell protective member for protecting the solar cell. For example, a solar cell cover glass is required. The solar cell cover glass is required to have high light transmittance and low reflection performance in order to obtain high light receiving efficiency, and a material having both ultraviolet resistance, water resistance, weather resistance and the like is preferred. Therefore, an inorganic material is preferable to an organic material such as a resin, and glass is particularly preferable because it is difficult to deteriorate and can maintain low reflection performance over a long period of time.

The low reflection film is used to reduce the light reflectance by coating the surface of the substrate.

Conventionally, for optical lenses and prisms, a multilayer film in which thin films having different refractive indexes and thicknesses are superimposed on a substrate, that is, a multi-coat has been favorably used. If the reflective film has a multilayer structure, reflection can be prevented in a wide wavelength range.

As described above, when the low reflection effect is obtained by utilizing the interference of light by the thin film coated on the surface of the low reflection member, it is important to adjust the refractive index and thickness of the film. When the refractive index of the substrate is n _s , the refractive index of the medium is n ₀ , and the wavelength of light is λ, the refractive index of the film having the lowest reflectance (theoretically zero) is obtained when there is a single low-reflection film. The rate n is represented by n = (n _s × n ₀ ) ^1/2 , and the film thickness d is represented by d = m (nλ / 4) (m = 1, 3, 5,...). Assuming that n ₀ is air≈1 and the refractive index n _s of a general base material is 1.4 to 1.7, theoretically n = 1.18 to 1.30, and a considerably low refractive index is obtained. It is done.

However, when a plurality of thin films are coated on the surface of the substrate by vacuum deposition or the like, precise control of the thickness of each thin film is necessary to achieve low reflection. If the transparent substrate is a large plate glass, a large vacuum film forming apparatus is required to multi-coat the large plate glass, which is technically difficult and both the apparatus and the low reflection member are expensive. There were drawbacks.

Therefore, recently, it has been desired to develop a low-reflection member with a low-reflection film that has a low reflection performance even though it is a single layer, which can produce a large-sized low-reflection member at low cost. In the low reflection film by a single layer film, it is preferable to use a film as close as possible to the theoretical refractive index.

As such a single layer film, there is an antiglare film that obtains a low reflection effect by utilizing diffused reflection of light by fine particles. To obtain low reflection in the antiglare film, the refractive index of the fine particles is different from that of the medium. In order to suppress interface reflection, the refractive index of the medium is required, and in the case of air, it is required to be closer to about 1.

For these reasons, a thin film of low refractive index magnesium fluoride (MgF ₂ , n = 1.38), which is an inorganic material, has been formed on the surface of a low reflection member. Magnesium fluoride thin films are mainly deposited by vapor deposition, but from the viewpoint of cost and workability, instead of the conventional vapor deposition method, an inexpensive and highly productive coating method suitable for large areas is required. Is done.

In order to satisfy this requirement, a coating film formed by applying magnesium fluoride fine particles on the surface has been used as a method for forming an inexpensive antireflection film suitable for a large area. Magnesium fluoride sols include aqueous sols obtained by concentrating a magnesium fluoride gel produced by adding an aqueous fluoride solution to an aqueous magnesium salt solution, and organosols obtained by phase-shifting an aqueous sol into an organic solvent. Known and disclosed in Patent Document 1 and Patent Document 2.

Patent Document 3 discloses a method for removing by-products by reacting magnesium fluoride produced in an organic solvent with a heat and pressure treatment using an autoclave after reaction.

Furthermore, Patent Document 4 discloses a support having an abrasion-resistant coating containing magnesium fluoride and a metal oxide. In addition, it is described that using hydrogen fluoride as a raw material for producing magnesium fluoride is inappropriate.

Further, as described above, in the low reflection film made of magnesium fluoride used in optical applications, as shown in Patent Documents 1 to 4, antireflection by coating the surface of the low reflection member with a low reflection film having a low refractive index. While the function is required, a method for imparting hydrophilicity to the low reflection member is required to prevent charging.

For example, in Patent Document 5, the surface of a base material coated with a fluoride such as magnesium fluoride is surface-modified by plasma irradiation or the like to manufacture a hardly-chargeable optical element in which hydrophilicity is introduced. A method is disclosed.

Patent Document 6 discloses an optical body that prevents water scuffing by forming a layer having photocatalytic activity such as titanium dioxide immediately below a magnesium fluoride layer in a multilayer antireflection film. . Patent Document 6 describes that magnesium fluoride is non-hydrophilic.

In addition, CIS thin film solar cells and crystalline silicon can absorb light in a wide wavelength range of 400 nm or more and 2000 nm or less, and can absorb light in a long wavelength range as compared with conventional amorphous silicon systems. It is known that the absorption peak is around 900 nm.

The method for forming an antireflection film described in Patent Document 1 and Patent Document 2 is synthesis of an organosol in an aqueous system, that is, synthesis using water, and by-product salt washing and concentration are performed by ultrafiltration. Therefore, there are problems in productivity and cost of the low reflection member.

In addition, in the method described in Patent Document 3, organic substances produced as a by-product are removed by heating and pressurizing with an autoclave. However, when the removal is not sufficient, the refractive index cannot be lowered by magnesium fluoride, and the organic substances are completely removed. There is a problem that the operation is complicated because it is necessary.

Further, although the support described in Patent Document 4 is excellent in abrasion resistance of the coating film, there is a problem in the storage stability of the mixed solution of magnesium fluoride and a specific metal oxide precursor, which is a coating solution.

In addition, in the method for producing a hardly-chargeable optical element of Patent Document 5, the lifetime of hydroxyl groups (OH groups) generated on the surface of the coating layer of the base material is short due to plasma irradiation or the like, and long-term hydrophilicity is expressed. Difficult, there is a problem that expensive equipment is required for application to the production of a low reflection member and is not general purpose.

Moreover, in the optical body described in Patent Document 6, by combining the low refractive index magnesium fluoride and the hydrophilic titanium oxide in the surface coating, the low reflectivity and the antifouling property of the optical body are compatible, Since the coating on the surface is a multilayer film, there is a problem that it takes too much time to apply it to the production of a low reflection member.

As described above, not only the problems of the inventions described in Patent Documents 1 to 5, but the low reflection film using magnesium fluoride has the following problems (1) to (4).

(1) In the case of a low-reflection film that uses light interference due to a thin film whose surface is easily noticeable, if dirt such as sweat or oil adheres, the dirt also interferes with the light as a thin film and the reflected image appears colored. As a result, the dirt becomes more prominent.

(2) In a thin film made of fine particles to which dirt easily adheres, since the surface has irregularities, it is difficult to remove the dirt once adhered, and labor is required to remove the dirt. In particular, in an antiglare film that has an uneven surface and scatters light to obtain an antireflection effect, dirt enters the recess and is difficult to remove.

(3) A low reflection film using magnesium fluoride, which is an insulator and is easily charged with static electricity, is easily charged with an insulator, and is hydrophobic and easily contaminated with oil, which is a contaminant.

As for (3), the surface resistance value of the magnesium fluoride film deposited on the surface of the glasses or the lens of the camera is 3.9 × 10 ¹² Ω · cm, and the magnesium fluoride film is an insulator. Further, the contact angle of the magnesium fluoride membrane with respect to pure water is 68 °, which is hydrophobic. For this reason, it is obvious that dirt such as sweat and dust is easily attached and easily contaminated. For example, Patent Document 5 describes that the surface of an optical element having a fluoride is easily charged, and thus the transmittance decreases.

(4) Since not only magnesium fluoride but fluoride is chemically stable, for example, it is difficult to form a chemical bond with a glass substrate even if it is attached to the surface of a glass substrate and heated and fired to form a coating. Adhesive strength with is weak. In addition, magnesium fluoride has a Mohs hardness of 6 and is not so hard, and has a problem that the film is inferior in wear resistance and the film is easily peeled off.

Since solar cells are exposed to wind and rain and ultraviolet rays when used outdoors, they require a protective member for the solar cell body, for example, a solar cell cover glass, and are already on the market.

Inorganic and organic pollutants such as dust, bird droppings and exhaust gas will adhere and block sunlight, leading to reduced power generation efficiency. Therefore, there is no low reflection film made of magnesium fluoride that solves all of the above problems (1) to (4), and the use of a magnesium fluoride film for a solar cell cover glass has been considered undesirable.

On the other hand, in the solar cell cover glass, in the case of an amorphous silicon type solar cell, the visible light 580 nm is the center, and in the crystal-Si and compound semiconductor type solar cells, the high transmittance is centered on the long wavelength region of 800 nm to 2000 nm. It is necessary to transmit light. In the solar cell cover glass, it is required to form on the surface a low reflection film for transmitting light in a wide wavelength range of 380 nm or more and 2000 nm or less, corresponding to a long wavelength region as well as conventional visible light. It is becoming.

JP 7-69621 A JP-A-2-26824 International Patent Publication No. WO2002 / 18982 Special table 2008-501557 gazette JP 2001-147302 A JP 2005-165014 A

The present invention has high light transmittance and low reflectance, strong adhesion strength to the substrate, excellent weather resistance, hydrophilicity, good antifouling property, antistatic function, and large area An object of the present invention is to provide a hydrophilic low-reflection member having a hydrophilic low-reflection film made of a single layer film that is easy to form.

In addition, it is suitable for use in solar cells using recent compound semiconductors and crystalline silicon, and has excellent light transmittance in a wide wavelength range of not less than 380 nm and not more than 2000 nm, as well as in the visible light range. An object is to provide a low reflection member.

The present invention is a hydrophilic low-reflection member having a transparent substrate and a hydrophilic low-reflection film formed on the transparent substrate, and has low reflection performance as a constituent component of the hydrophilic low-reflection film. Instead of hydrophilic magnesium fluoride, magnesium hydroxide fluoride fine particles having a hydroxyl group in the molecule were used, and a refractive index adjusting material was used as a binder.

In the present invention, a hydrophilic low reflection member obtained by coating a hydrophilic low reflection film having a refractive index of 1.23 or more and 1.41 or less was obtained. In the formation of a hydrophilic low-reflection film, magnesium hydroxide fluoride fine particles are bonded as a binder, that is, a binder, to form an amorphous film, or a void can be formed as a microscopic void. When the air is taken in, a refractive index of 1.41 or less becomes possible. Preferably it is 1.38 or less, More preferably, it is 1.35 or less, More preferably, it is 1.30 or less.

That is, the present invention is a hydrophilic low-reflection member having a transparent base material and a hydrophilic low-reflection film formed on the transparent base material, wherein the hydrophilic low-reflection film comprises magnesium hydroxide fluoride fine particles and And at least one metal oxide selected from the group consisting of tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide and tantalum oxide as a refractive index adjusting material. It is a hydrophilic low reflection member characterized by being 23 or more and 1.41 or less. Preferably, it is 1.38 or less. More preferably, it is 1.35 or less, More preferably, it is 1.30 or less. In particular, tungsten compounds, niobium compounds and tantalum compounds are easy to disperse or dissolve, and preparation of the coating solution is easy, and it is easy to make oxides by coating and baking the coating solution, especially tungsten oxide, niobium oxide and tantalum oxide, Easy to use as a metal oxide in a hydrophilic low reflection film.

In the present invention, fine particles are particles having a maximum particle size of 500 nm or less, and the refractive index is a value measured with an ellipsometer by spectroscopic ellipsometry measurement at a wavelength of 637 nm.

In the present invention, magnesium hydroxide fluoride fine particles having a particle diameter of 3 nm or more and 100 nm or less are selected from the group consisting of tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide and tantalum oxide as a refractive index adjusting material. When at least one kind of the metal oxide is used and coated and baked on the surface of the glass substrate as a transparent base material to form a hydrophilic low reflection film, it is colorless with good light transmission in a wavelength range of 380 nm to 2000 nm. A hydrophilic low-reflection member having a transparent and durable hydrophilic low-reflection film was obtained.

In the present invention, the particle size of the magnesium hydroxide fluoride fine particles is 3 nm or more and 100 nm or less. If it is less than 3 nm, voids between particles become small, and as a result, the number of exposed hydroxyl groups tends to be small, and the hydrophilicity may be lowered. On the other hand, if the thickness exceeds 100 nm, the contact points between the particles and between the particles and the substrate become small, and the adhesion of the fine particles to the substrate may be reduced. More preferably, they are 5 nm or more and 60 nm or less, More preferably, they are 8 nm or more and 20 nm or less. The particle diameter is a value obtained by observation with a scanning electron microscope (hereinafter abbreviated as SEM), and is the maximum diameter of the magnesium hydroxide fluoride fine particles, and the total number of magnesium hydroxide fluoride fine particles in the field of view of the SEM. It is preferable that 90% or more of is within the range of the particle diameter.

In addition, the colorless and transparent film was obtained because at least selected from the group consisting of tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide, and tantalum oxide as a refractive index adjusting material for magnesium hydroxide fluoride fine particles. By adding one or more kinds of metal oxides, the resulting low reflection film becomes a more amorphous film. By being an amorphous film, the low reflection film is formed on the surface of the transparent substrate. This is probably because the transparency of the low-reflective member increased.

The average transmittance and average reflectance are values obtained by measuring the transmittance and reflectance of light in the wavelength range of 380 nm to 2000 nm using a spectrophotometer, and calculating the average transmittance and average reflectance in the wavelength range. is there. The transmittance curve is a curve obtained by continuously plotting measured values of light transmittance with a spectrophotometer in a certain wavelength range.

The magnesium hydroxide fluoride contained in the hydrophilic low reflection film formed on the surface of the hydrophilic low reflection member of the present invention is a compound having a hydroxyl group. This can be confirmed by X-ray diffraction (XRD) data, and the X-ray diffraction pattern agrees with the data of magnesium hydroxide fluoride (MgF _1.89 (OH) _0.11 ) in JCPDS file 54-1272. Admitted to do. Compared with magnesium fluoride, magnesium hydroxide fluoride is amorphous and has a hydroxyl group. Therefore, when it is contained in the low reflection film, it shows hydrophilicity, and a hydrophilic low reflection film is formed.

The present invention also provides the above hydrophilic low-reflection member, wherein the magnesium hydroxide fluoride is MgF _2-x (OH) _x (x = 0.01 to 0.5). Among these, the magnesium hydroxide fluoride is preferably MgF _1.89 (OH) _0.11 .

Furthermore, the present invention is the above-described hydrophilic low-reflection member, wherein the difference between the average transmittance of the transparent base material before the formation of the hydrophilic low-reflection film at 380 nm or more and 2000 nm or less is 6% or more. is there.

In the hydrophilic low reflection member of the present invention, the hydrophilic low reflection film is at least one selected from the group consisting of magnesium hydroxide fluoride, tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide, and tantalum oxide. In addition to the above-mentioned metal oxides, silica (SiO ₂ ), alumina (Al ₂ O ₃ ), ceria (CeO ₂ ), zirconia (ZrO ₂ ), titania (TiO ₂ ), tin oxide, At least one metal oxide selected from the group consisting of indium oxide, zinc oxide, antimony oxide, and lanthanum oxide may be added.

In particular, silica (SiO ₂ ), alumina (Al ₂ O ₃ ), ceria (CeO ₂ ), zirconia (ZrO ₂ ), and titania (TiO ₂ ) are useful for adjusting the hardness of the low reflective film. Tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide, and tantalum oxide have conductivity, but the refractive index adjusting material was selected from tin oxide (SnO ₂ ), indium oxide, zinc oxide, or antimony oxide. When a metal oxide having high conductivity and antistatic ability is used for the hydrophilic low reflection member of the present invention, the surface resistance value of the hydrophilic low reflection member is 1 × 10 ¹⁰ Ω. It becomes cm or less, and it becomes possible to impart an antistatic function to the hydrophilic low reflection member.

Further, the present invention provides at least one metal oxide selected from the group consisting of tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide and tantalum oxide as a refractive index adjusting material, silica, alumina, The hydrophilic low-reflective member as described above, wherein at least one metal oxide selected from the group consisting of ceria, zirconia, titania, tin oxide, indium oxide, zinc oxide, antimony oxide and lanthanum oxide is added. It is.

At that time, if the molar ratio of magnesium hydroxide fluoride and the refractive index adjusting material is greatly different, there is a concern of gelation. In the hydrophilic low reflection member of the present invention, the molar ratio of the refractive index adjusting material to magnesium hydroxide fluoride in the hydrophilic low reflection film is preferably in the range of 0.5: 10 to 30:10.

Furthermore, in the hydrophilic low reflection member of the present invention, the contact angle of water on the hydrophilic low reflection film surface is preferably 30 ° or less.

Furthermore, in the hydrophilic low reflection member of the present invention, the surface resistance value of the hydrophilic low reflection film surface is preferably 1 × 10 ¹⁰ Ω. cm or less.

Furthermore, the present invention provides a surface protection member for a solar cell characterized by using the above hydrophilic low reflection member. Examples of the solar cell surface protective member include a solar cell cover glass.

The hydrophilic low-reflection film formed on the surface of the hydrophilic low-reflection member of the present invention is obtained by adding magnesium hydroxide fluoride fine particles to the metal (that is, at least selected from tungsten, molybdenum, chromium, vanadium, niobium and tantalum). A coating liquid in which a compound of one or more metals), for example, metal alkoxide is added and magnesium hydroxide fluoride fine particles are dispersed is applied and coated on the surface of the transparent substrate by a sol-gel method, followed by baking. In this firing, metal alkoxide is precipitated and fired between magnesium hydroxide fluoride and becomes a binder for binding magnesium hydroxide fluoride, and air having a refractive index of 1 is taken into voids between the magnesium hydroxide fluoride. Due to the effect, the film has a refractive index of 1.38 or less.

Furthermore, the hydrophilic low-reflective member of the present invention is obtained by coating and coating a transparent substrate surface with a coating solution in which the above metal compound is added to magnesium hydroxide fluoride fine particles and the magnesium hydroxide fluoride fine particles are dispersed. It has the hydrophilic low-reflection film which becomes.

That is, the present invention provides a coating liquid obtained by adding at least one metal compound selected from the group consisting of tungsten, molybdenum, chromium, vanadium, niobium and tantalum to magnesium hydroxide fluoride fine particles. Provided is a method for producing the above hydrophilic low-reflection member, characterized by firing after coating on the surface.

Further, the present invention provides magnesium hydroxide fluoride fine particles, at least one metal compound selected from the group consisting of tungsten, molybdenum, chromium, vanadium, niobium and tantalum, and silicon, aluminum, cerium, zirconium, After applying at least one metal compound selected from the group consisting of titanium, tin, indium, zinc, antimony and lanthanum, and applying a coating liquid in which magnesium hydroxide fluoride fine particles are dispersed to the surface of the transparent substrate And providing a method for producing the above hydrophilic low-reflection member, characterized by firing.

In particular, compounds of tungsten, niobium, tantalum, silicon and aluminum are easy to prepare and use in dispersions and solutions.

2 is a SEM photograph of the glass substrate surface on which a film is formed in Example 1. FIG. 4 is a SEM photograph of the glass substrate surface on which a film is formed in Example 2. It is the transmittance | permeability curve of the glass substrate in which the film was formed in Example 2. FIG. 4 is a SEM photograph of the glass substrate surface on which a film is formed in Example 3. It is the transmittance | permeability curve of the glass substrate in which the film was formed in Example 3. FIG.

Detailed description

The present invention contains magnesium hydroxide fluoride fine particles and at least one metal oxide selected from the group consisting of tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide and tantalum oxide as a refractive index adjusting material. A hydrophilic low reflection film (single layer film) with low refractive index, high transparency, excellent hydrophilicity and durability is formed on the surface of a transparent substrate by a wet coating method. The low reflective member was able to be obtained. Since it has hydrophilicity, it is excellent in antifouling property and can be easily washed away even when dirt is attached. Further, if the transparent substrate is glass, the magnesium hydroxide fluoride and the glass surface are firmly bonded, and film peeling hardly occurs.

Further, in addition to the metal, at least one metal compound selected from the group consisting of silicon, aluminum, cerium, zirconium, titanium, tin, indium, zinc, antimony and lanthanum is contained in the hydrophilic low reflection film. Thus, a hydrophilic low-reflection film having hardness and excellent wear resistance was obtained.

That is, the hydrophilic low reflection member of the present invention has both excellent low reflection performance and hydrophilic performance, antistatic performance, and excellent antifouling properties represented by self-cleaning properties. The above properties can be obtained with a single-layer hydrophilic low-reflection film.

Further, the hydrophilic low reflection member of the present invention has a wide light transmission performance not only in the visible light region but also in the near infrared region, and is excellent in light transmittance in a wide wavelength region of 380 nm or more and 2000 nm or less. It is useful as a protective member. When a glass substrate is used as the transparent substrate, it is particularly useful as a solar cell cover glass.

The present invention is a hydrophilic low-reflection member having a transparent substrate and a hydrophilic low-reflection film formed on the transparent substrate, the hydrophilic low-reflection film comprising magnesium hydroxide fluoride fine particles, It contains at least one metal oxide selected from the group consisting of tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide and tantalum oxide as a refractive index adjusting material, and has a refractive index of 1.23. As described above, the hydrophilic low-reflection member is 1.41 or less. Preferably, it is 1.38 or less, More preferably, it is 1.35 or less, More preferably, it is 1.30 or less.

Due to the effect of magnesium hydroxide fluoride contained in the hydrophilic low reflection film formed on the surface of the hydrophilic low reflection member of the present invention, the hydrophilic low reflection film has a refractive index of 1.23 or more and 1.41 or less. Refractive index. Furthermore, when forming a hydrophilic low-reflection film, magnesium hydroxide fluoride fine particles become amorphous when a metal oxide is bonded as a binder, that is, a binder, or voids that are microvoids are formed. By taking in air having a refractive index of 1, a refractive index of 1.41 or less is possible.

Further, when the magnesium hydroxide fluoride has a hydroxyl group, the hydrophilic low-reflection film exhibits hydrophilicity, and the hydrophilic low-reflection member has a hydrophilic low-reflection function having both low reflection and hydrophilicity. Only magnesium hydroxide fluoride fine particles were formed on both sides of a transparent base material, for example, a glass substrate, and the light transmittance was measured. In the ultraviolet to visible range, it was generally 5% or more and 8% or less than the glass substrate. It was confirmed that the film has a high transmittance and exhibits excellent optical properties. In particular, the hydrophilic low reflection film exhibits a low refractive index in the visible light region near a wavelength of 550 nm, and brings high light transmittance to the hydrophilic low reflection member. However, in the near-infrared region of wavelengths of 800 nm or more and 2000 nm or less, the light transmittance is considerably reduced and is only 2% to 3% higher than that of an untreated glass substrate having no hydrophilic low reflection film. In order to obtain a hydrophilic low reflection film in the region, there is room for improving the film quality.

On the other hand, the hydrophilic low reflection member of the present invention is obtained by applying a coating liquid obtained by adding a specific metal oxide raw material compound as a refractive index adjusting material to a dispersion of magnesium hydroxide fluoride fine particles. Then, a hydrophilic low reflection film is formed by a so-called sol-gel method. By adding a specific metal oxide as a refractive index adjusting material to the magnesium hydroxide fluoride fine particles, the light transmittance in the near infrared region of the wavelength of 800 nm or more and 2000 nm or less of the hydrophilic low reflection film was improved.

Details are shown below.
In general, a metal oxide thin film is formed on a surface of an optical member by, for example, applying and baking a dispersion of a metal compound, and is useful as a means for improving the optical characteristics of the optical member. Is not necessarily low. For example, the refractive index of the metal oxide thin film alone is as follows: silica, 1.45, alumina, 1.61, tin oxide, 1.68, zirconium oxide, 1.86, titanium oxide, 2.15, oxidation. Tantalum, 2.3.

Metal oxides having a relatively low refractive index, such as silica and alumina, are widely used as optical thin films on the surface of optical members. However, the glass substrate on which the silica film of silica alone is formed shows a slightly higher light transmittance than the glass substrate on which the silica film is not formed, but shows a particularly high light transmittance in the near infrared region with a wavelength of 800 nm or more and 2000 nm or less. Do not mean.

On the other hand, a metal oxide having a large refractive index is difficult to use as a low reflection film. When a film of zirconium oxide, tantalum oxide or titanium oxide, which is a metal oxide having a high refractive index, is formed alone on a glass substrate, for example, a coating solution in which these metal compounds are dispersed can be fired at a high temperature at 550 ° C. The refractive index of the metal oxide thin film is 1.85 to 2.2. The reflectance of a glass substrate on which these metal oxide thin films are formed is 10% to 20%, which is higher than that of an untreated glass substrate having no film formed on the surface, and can be used as a low reflection film. It is not a thing. When these metal oxide thin films were subjected to X-ray diffraction, metal oxide crystals were observed.

Even in an optical member in which a thin film using two or more kinds of the metal oxide is formed on the surface of the glass substrate, the reflectance is higher than that of the untreated glass substrate. For example, a metal oxide composed of TiO ₂ and SiO ₂ The glass substrate with a metal oxide thin film having a thin film formed on the surface thereof showed lower light transmittance than the glass substrate in the visible region and near infrared region having a wavelength of 380 nm or more and 2000 nm or less.

Thus, a glass with a metal oxide thin film made of a metal oxide having a higher refractive index than glass, such as tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide, tin oxide, titanium oxide, zirconium oxide, and tantalum oxide. Since the substrate is inferior in light transmittance in the visible range and near infrared range of wavelengths of 380 nm or more and 2000 nm or less, it is not usually performed to use magnesium hydroxide fluoride and the metal oxide for the metal oxide thin film.

However, as a result of intensive studies by the present inventors, in the metal oxide thin film, at least selected from the group consisting of magnesium hydroxide fluoride, tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide, and tantalum oxide. It has been found that the light transmittance in the near infrared region of the glass substrate with a metal oxide thin film is increased by adding one or more metal oxides.

In the metal oxide thin film after being applied and fired by the sol-gel method, the magnesium hydroxide fluoride fine particles and the metal oxide exist in an amorphous state in the thin film. X-ray diffraction of the fired thin film revealed that the magnesium hydroxide fluoride peak was the main component, and the other metal oxides were in an amorphous state with almost no crystal peak.

It is presumed that this amorphous state suppresses an increase in refractive index in the thin film and a decrease in light transmittance in the glass substrate with the thin film. The phenomenon that the thin film becomes amorphous becomes more remarkable as the types of the metal oxides to be contained in the thin film together with the magnesium hydroxide fluoride fine particles are increased.

That is, when a thin film using magnesium hydroxide fluoride and a metal compound as appropriate is formed on the surface of a transparent substrate by sol-gel method and formed by baking, the crystallization of the metal oxide is suppressed by baking at a high temperature. Thus, it was estimated that a part of the metal oxide was present in an amorphous state, and the refractive index of the obtained film was not increased, and a more preferable hydrophilic low-reflection film was obtained.

In the present invention, even a metal oxide that crystallizes if it does not contain magnesium hydroxide fluoride exists in an amorphous state in the presence of magnesium hydroxide fluoride, compared to the case of crystallization. It is considered that the refractive index of the metal oxide has an effect of being kept low. This amorphization of the metal oxide is a characteristic action in the present invention that is considered to be caused by the coexistence of magnesium hydroxide fluoride with the metal oxide. Based on this knowledge, the inventors of the present invention have a hydrophilic low reflection film formed on the surface of the hydrophilic low reflection member of the present invention. Magnesium hydroxide is high in a wide wavelength range as a refractive index adjusting material. We have found specific metal oxides that provide transmittance.

That is, a film containing a metal oxide having a high refractive index (tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide, zirconium oxide titanium oxide, and tantalum oxide) and magnesium hydroxide fluoride unexpectedly. It was found that it can be used as a refractive index adjusting material.

The refractive index of magnesium hydroxide fluoride alone is 1.23 or more and 1.41 or less. As described above, magnesium hydroxide fluoride fine particles are bonded as a metal oxide binder, and air with a refractive index of 1 is taken in. Lower than 1.38 which is the theoretical value of the refractive index of magnesium fluoride due to the fact that the film has a small void and the structure of the film containing magnesium hydroxide fluoride is different from that of magnesium fluoride. Can be a value.

In addition, since magnesium hydroxide fluoride has a high light transmittance at a wavelength of 550 nm, it can be analogized that a film with a metal oxide similarly gives a transmission curve having a peak at a wavelength of 550 nm. When mixed with an object, the peak of maximum transmittance slightly shifts to the longer wavelength side, and the light transmittance in the near infrared region tends to increase accordingly.

Fine particles of magnesium hydroxide fluoride, tungsten oxide (WO ₃ , refractive index 2.2), molybdenum oxide (MoO ₂ , MoO ₃ ), chromium oxide (Cr ₂ O ₃ etc., refractive index 2.2), vanadium oxide (Vanadium pentoxide: V ₂ O ₅ , refractive index 2.3), niobium oxide (niobium pentoxide: Nb ₂ O ₅ , refractive index 2.3) and tantalum oxide (tantalum pentoxide: Ta ₂ O ₅ , refractive index This tendency is remarkable in the film formed by applying and baking at least one selected from 2.2) by the sol-gel method, and the light transmission of the low reflection member in the near infrared region of wavelengths of 800 nm or more and 2000 nm or less. The rate was improved.

Further, in the case of a single film, alumina (n = 1.61) whose transmittance on the long wavelength side of the optical member was not particularly high was also allowed to coexist with magnesium hydroxide fluoride, so that the wavelength was 600 nm or more. In the near-infrared region of 800 nm or less, an improvement in light transmittance was observed in the optical member.

Further, when zirconium oxide (n = 1.68) was formed on a glass substrate, the transmittance was lower than that of the glass substrate at all wavelengths, but a film in which magnesium hydroxide fluoride and zirconium oxide coexisted was used. When the film was formed on a glass substrate, an improvement in transmittance was observed at wavelengths of 700 nm to 900 nm.

As described above, the film containing magnesium hydroxide fluoride and each metal oxide also has compatibility, and in a specific combination, the optical characteristics of the thin film are merely a simple average value of refractive index. Don't be. When magnesium hydroxide fluoride and a specific metal oxide coexist, there is a tendency to increase the transmittance in a specific wavelength range. Although the wavelength range cannot be strictly defined, when the refractive index of the metal oxide is low, the peak of the transmittance curve of the thin film is slightly longer than the transmittance peak of magnesium hydroxide fluoride. shift. As the refractive index of the metal oxide increases, the peak further appears on the longer wavelength side.

Therefore, by utilizing this property, when several kinds of metal oxides having different refractive indexes coexist with magnesium hydroxide fluoride in a thin film, for example, a metal oxide having a low refractive index has a transmittance in the visible region. Since metal oxides with a high refractive index tend to increase the transmittance in the near-infrared region, by combining these appropriately, the metal oxide functions as a refractive index adjusting material, and in a wide wavelength range, It seems to increase the transmission.

In order to keep the refractive index low in the coexistence with magnesium hydroxide fluoride, the metal oxide having a low refractive index is contained more than the metal oxide having a high refractive index. That is, a large amount of silica or alumina having a low refractive index is contained, for example, 0.5 mol or more and 8 mol or less, more preferably 1 mol or more and 6 mol or less, mixed with 10 mol of magnesium hydroxide fluoride. Is possible. A medium refractive index tin oxide, yttrium oxide or the like is contained in an amount of 0.5 mol or more and 7 mol or less, preferably 1 mol or more and 5 mol or less. High refractive index tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide and tantalum oxide can also be included.

For example, tantalum oxide can be contained in an amount of 0.5 mol or more and 6 mol or less, preferably 1 mol or more and 4 mol or less. Here, in the coexistence with magnesium hydroxide fluoride, it is not always necessary to increase the content of the metal oxide having a low refractive index, and it may be appropriately adjusted so that the refractive index of the thin film can be kept low.

Moreover, in addition to ceria and lanthanum oxide as rare earth metal oxides, yttrium oxide, samarium oxide, and erbium oxide can be used.

In the hydrophilic low-reflection film formed on the surface of the hydrophilic low-reflection member of the present invention, if the amount of metal oxide added is too large relative to magnesium hydroxide fluoride, the refractive index increases and the low-reflection film is not formed. It is not preferable. On the other hand, when the addition amount is too low, magnesium hydroxide fluoride is the main component, and thus the visible light transmittance near 550 nm increases. However, when the amount is 800 nm or more, the transmittance is significantly reduced, which is not preferable. By appropriately adjusting the addition amount, it is possible to greatly increase a wide transmittance not only to ultraviolet light and visible light but also to the near infrared region.

This is contrary to the conventional concept of refractive index of multi-component thin films. A thin film in which a plurality of metal oxides coexist in magnesium hydroxide fluoride has a specific metal oxide as described above. It is believed to be responsible for increasing the transmission of the film in the wavelength range, and increasing the visible light and near infrared transmission of the film.

In the vapor deposition method and the sputtering method, it is difficult to form a thin film composed of several kinds of components on the surface of the substrate by a single film formation, but in the wet coating method represented by the sol-gel method, the thin film composed of several kinds of components is 1 It can be formed by a single coating and baking. This is expected to be applied to improve the transmittance of a wide range of optical members in the ultraviolet, visible and infrared regions, and can be applied to optical members of all wavelengths such as steppers, lasers, organic EL, liquid crystal display elements, LEDs, lighting fixtures, and lenses. Is possible.

In addition, by using several kinds of the above metal oxides at the same time, the metal oxide is bonded to, for example, the oxide in the glass substrate. As a result, the wear resistance is remarkably improved.

Further, when the hydrophilic low-reflection film of the present invention formed using tantalum oxide as a refractive index adjusting material was subjected to Auger analysis while etching, the fluorine content gradually decreased in the depth direction, and the tantalum content was reduced. Gradually increased. Furthermore, oxygen and silicon increased rapidly and tantalum and fluorine disappeared completely at the boundary surface between the hydrophilic low-reflection film and the glass plate as the transparent substrate.

According to the results of this Auger analysis, in a 115 nm-thick single layer film, the surface is rich in magnesium hydroxide fluoride, and the content of magnesium hydroxide fluoride gradually decreases in the depth direction. It seems that the content of tantalum oxide as a rate adjusting material gradually increased in the depth direction.

Thus, the results of Auger analysis suggested that the refractive index continuously changed from the low refractive index to the high refractive index in the depth direction from the surface layer. Thus, in the hydrophilic low-reflection film formed on the surface of the hydrophilic low-reflection member of the present invention, the refractive index of the surface layer portion of the film is low, and the refractive index increases as it goes deeper in the film, as if multiple layers It is presumed that the effect of laminating the films was obtained, and a film having good low reflection performance was obtained although it was a single layer.

This phenomenon is caused by adjusting the refractive index of fine particles of magnesium hydroxide fluoride having a particle diameter of 3 nm or more and 100 nm or less to form a hydrophilic low reflection film on the surface of the transparent substrate in the hydrophilic low reflection member of the present invention. This occurs when a metal oxide is mixed as a material, and is prominent when a metal oxide selected from the group consisting of tungsten oxide, molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide, and tantalum oxide is used as the metal oxide. It seems that a lower reflectance can be obtained. This is particularly noticeable when tungsten oxide, chromium oxide, niobium oxide or tantalum oxide is used, and these metal oxides are preferably used as the refractive index adjusting material of the low reflection film of the present invention.

In the present invention, the molar ratio of the metal oxide as a refractive index adjusting material to magnesium hydroxide fluoride is preferably 0.5: 10 to 30:10, particularly preferably 1:10 to 2.5: 10. When the refractive index adjusting material is less than 0.5 mol with respect to 10 mol of magnesium hydroxide fluoride, the film is mainly composed of magnesium hydroxide fluoride, and the film strength represented by wear resistance is inferior. . Moreover, when there are more refractive index adjustment materials than 30 mol with respect to 10 mol of magnesium hydroxide fluoride, since a coating liquid will become unstable and gelatinize in several days, it is unpreferable.

In the present invention, the coexistence of magnesium hydroxide fluoride and metal oxide makes it possible to keep the refractive index of the film low, and the molar ratio of the refractive index adjusting material to magnesium hydroxide fluoride is 0.5. : Within the range of 10 to 30:10, the coating solution did not gel, and a hydrophilic low-reflection film with suitable film strength could be formed.

As mentioned above, the main effect of coexisting metal oxide with magnesium hydroxide fluoride is to increase the transmittance in the near infrared region, which cannot be improved by magnesium hydroxide fluoride alone, from visible light to the near infrared region. It is possible to adjust the refractive index of the film relatively low. In addition, there are the following effects.

That is, as a coexistence effect of the metal oxide, the refractive index of the film can be adjusted by adding to [1] magnesium hydroxide fluoride, so that the film thickness can be arbitrarily changed. (Effects as a refractive index adjusting material)
[2] Change the transmittance. It becomes possible to improve the transmittance in a wide range of wavelengths of not only visible light but also ultraviolet and infrared light. (Adjustment of transmittance)
[3] Increase film strength (increased adhesion strength and friction strength with substrate)

Since magnesium hydroxide fluoride is not an oxide, it is not bonded to a transparent base material such as a glass substrate, so that it is inferior in film strength by itself. Here, when a certain amount of a specific metal oxide is added, it is bonded to the base material in a state of being mixed with the magnesium hydroxide fluoride fine particles, and the adhesive strength is increased. is there.

[4] A hydroxyl group of magnesium hydroxide fluoride is present on the surface layer after the coating is formed, to exert a hydrophilic effect, maintain hydrophilicity for a long time, and have a self-cleaning function.
[5] By synthesizing a conductive metal oxide such as SnO ₂ or In ₂ O ₃ as the metal oxide, the synergistic effect of the hydroxyl group of magnesium hydroxide fluoride and the conductive metal oxide after film formation Thus, the antistatic effect is maintained and the antifouling function is maintained for a long time.

Hereinafter, magnesium hydroxide fluoride, organosol production process, and metal oxide will be described.

[Magnesium hydroxide fluoride]
The magnesium hydroxide fluoride used in the present invention is a compound having a hydroxyl group. This can be confirmed by X-ray diffraction data, and it was confirmed that the X-ray diffraction pattern coincided with magnesium hydroxide fluoride (MgF _1.89 (OH) _0.11 ) of JCPDS file 54-1272. Magnesium hydroxide fluoride has amorphous properties and exhibits hydrophilicity as described later.

Such remarkable amorphousness is not described in the preceding examples. The spectrum of X-ray analysis of magnesium fluoride (MgF ₂ · nH ₂ O) having crystal water shown in Patent Document 1 (FIG. 1 of Patent Document 3) also shows a peak with good crystallinity similar to Reference Example 1 above. And greatly different from the magnesium hydroxide fluoride used in the present invention. The X-ray analysis shown in Patent Document 1 does not have a description of the JCPD file number, and it is understood that it is different from magnesium hydroxide fluoride.

Magnesium hydroxide fluoride of the present invention is formed on a soda lime silicate glass plate alone, the refractive index is very low, the lower limit is 1.26, far from the literature value of 1.38 for magnesium fluoride. It showed a low value. This was estimated to be due to the fact that magnesium fluoride with a refractive index of 1.38 became a porous film containing a large amount of air with a refractive index of 1.0, but the film weight and film thickness were precisely measured. Then, when the density of the coating was determined, it was found that the coating was tightly packed and contained almost no air. This low refractive index is presumed to be due to the fact that magnesium hydroxide fluoride has a crystal structure different from that of conventional magnesium fluoride.

The film made only of magnesium hydroxide fluoride formed on the surface of the glass substrate showed a refractive index of 1.26 which is very close to the theoretical value of 1.22. Therefore, even with a single layer film, the reflectance was low in a wide range of visible light, and excellent antireflection characteristics were exhibited. For example, it was 0.05% at a wavelength of 550 nm.

On the other hand, a compound obtained by adding adhering water to magnesium fluoride described in Patent Document 1 shows a refractive index of 1.37. Therefore, when compared with the same single layer film, the compound is lower than magnesium hydroxide fluoride of the present invention. The reflection characteristics are inferior. Judging from the analysis results of the X-ray powder diffraction method (X-Ray Diffraction Method, XRD) and the difference in optical properties in refractive index and low reflection performance, magnesium hydroxide fluoride and fluoride described in Patent Document 1 are used. Magnesium compounds are completely different substances.

As described above, the magnesium hydroxide fluoride film has a lower refractive index than the magnesium fluoride film and is more preferably used as a material for the hydrophilic low reflection film. In addition, it has a stable hydroxyl group in the molecule, unlike the one with attached water, so it exhibits excellent hydrophilicity, exhibits antifouling properties, and can be easily washed away even when dirt is attached. The effect that can be expected.

Also, in order for the film surface to exhibit hydrophilicity, it is generally desirable that the surface be covered with a hydroxyl group. In the present invention, since the magnesium hydroxide fluorinated fine particles have a hydroxyl group, the hydroxyl group is exposed on the surface. Further, since the fine particles have a hydroxyl group, the adhesion of the fine particles to the substrate is improved.

As a result of examination, the fine particles have fewer hydroxyl groups than simple hydroxides but are sufficiently hydrophilic. Furthermore, since the magnesium hydroxide fluorinated magnesium of the present invention is chemically more stable than a simple hydroxide, the low reflection member provided with the hydrophilic film made of the fine particles is excellent in reliability for long-term use. Conceivable.

In the present invention, magnesium hydroxide fluorinated magnesium is formed into fine particles by dropping a hydrogen fluoride aqueous solution into a liquid in which the magnesium raw material is dispersed, suspended or dissolved, so that the magnesium compound as the magnesium raw material is fluorinated and given hydroxyl groups. Can be used.

The magnesium compound is selected from inorganic compounds of magnesium chloride, magnesium oxide or magnesium carbonate, and is preferably used. Although it is possible to use a magnesium compound selected from magnesium alkoxide and magnesium carboxylate, when these organic compounds are used, the viscosity of the sol in which magnesium hydroxide is dispersed tends to increase. Inorganic compounds are preferred, and magnesium chloride and magnesium carbonate are more preferred for the problem of removing by-products described later.

An organic solvent is suitably used as the solvent used as the dispersion medium. Since an aqueous hydrogen fluoride solution is added during the reaction, a protic polar organic solvent highly compatible with water is more preferable. As such a solvent, alcohols, acids and the like can be used. The alcohol is an alcohol having 1 to 10 carbon atoms, preferably an alcohol having 1 to 4 carbon atoms, or a glycol ether having 2 to 20 carbon atoms. Examples of the alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, isopropanol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol and tert-butyl alcohol, and a glycol having 2 to 20 carbon atoms. Examples of ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether or dipropylene glycol monomethyl ether. . Among these, methanol, ethanol or isopropanol is preferable as the alcohol, and diethylene glycol monomethyl ether or diethylene glycol monoethyl ether is preferable as the glycol ether.

[Process for producing organosol containing magnesium hydroxide fluoride fine particles]
Hereinafter, the manufacturing process of the organosol containing the magnesium hydroxide fluoride fine particles used in the present invention will be described. This manufacturing process includes the following three steps (a), (b), and (c).
(A) A step in which an aqueous solution of hydrofluoric acid is gradually added dropwise to a solution obtained by dispersing, suspending, or dissolving a magnesium compound in an organic solvent to gradually produce magnesium hydroxide fluoride fine particles. Step of removing product or excess hydrogen fluoride (c) Step of changing solvent concentration or adjusting solvent concentration of sol obtained in steps (b) to form organosol

In the step (a), the size of the magnesium compound particles may be any particle that can form a dispersion or suspension. For example, the average particle size is 0.1 μm or more and 800 μm or less, preferably 0.3 μm. As mentioned above, the thing of 500 micrometers or less is used. The average particle diameter may be measured according to JIS K1150 (1994).

Further, the content of the magnesium compound in the dispersion or suspension is 0.01 mol / L (liter) or more and 5 mol / L or less. When the content is less than 0.01 mol / L, the production rate of magnesium hydroxide fluoride fine particles tends to be low. When the content is higher than 5 mol / L, when an aqueous solution of hydrofluoric acid is added dropwise to a magnesium compound dispersion or suspension, gelation occurs instantaneously, and the viscosity of the mixture increases, causing the magnesium compound and fluorine to be mixed. It is not preferable because the reaction with hydrogen fluoride hardly proceeds uniformly. Preferably, they are 0.05 mol / L or more and 2 mol / L or less.

The concentration of hydrofluoric acid in the hydrofluoric acid aqueous solution is 5% by mass or more and 60% by mass or less. When the concentration of hydrofluoric acid is less than 5% by mass, the production rate of magnesium hydroxide fluoride fine particles tends to be low. When the concentration of hydrofluoric acid is more than 60% by mass, colloids may be rapidly formed in the reaction system and gelled, which is not preferable because it inhibits the formation of magnesium hydroxide fluoride fine particles. Preferably they are 10 mass% or more and 58 mass% or less.

A solution containing hydrofluoric acid is prepared by adding hydrofluoric acid to water, lower alcohols such as methanol, ethanol or isopropanol, ketones such as acetone or methyl ethyl ketone, esters such as ethyl acetate or isopropyl acetate, or the like. It can be prepared by adding ethers such as diethyl ether or tetrahydrofuran as a solvent.

Magnesium hydroxide fluoride exhibits sufficient hydrophilicity even when the ratio of fluorine atoms to magnesium is increased. Therefore, in order to impart the characteristics of fluorine atoms, the ratio of fluorine atoms is adjusted to be high. It is preferable. Therefore, the mixing ratio of the magnesium compound and hydrogen fluoride can be mixed under the condition that all the magnesium compound is consumed. The number of moles of hydrogen fluoride added to the magnesium compound is 1 to 2 times the number obtained by multiplying the number of moles of Mg by the valence of 2, preferably 1 to 1.5 times, more preferably 1 to 1.2 times. When another metal compound (for example, a calcium compound described later) is included as an auxiliary material, the above range is preferable on the basis of the sum of numerical values obtained by multiplying the number of moles of magnesium and each metal compound by the valence. The pH after the reaction is adjusted to a range of 1 to 4.

The reaction temperature of this reaction is usually from −20 ° C. to the boiling point of the solvent. Specifically, it is −20 ° C. or higher and 80 ° C. or lower. When the reaction temperature is lower than −20 ° C., the reaction rate becomes slow and a cooling device is required, which is not preferable. On the other hand, when the reaction temperature exceeds 80 ° C., the boiling point of hydrogen fluoride is low, so that it volatilizes immediately after the addition and is not used effectively, and hydrogen fluoride gas is generated, which is dangerous. Further, the reaction proceeds rapidly immediately after the addition, and the produced colloid is locally aggregated or gelled, which is not preferable. Preferably, they are 0 degreeC or more and 50 degrees C or less.

In the formation reaction of the magnesium hydroxide fluoride organosol, it is preferable to gradually advance the reaction between the magnesium compound and hydrogen fluoride because of the effect of increasing the uniformity of the organosol. Specifically, the concentration of the dispersoid in the dispersion is low, the addition rate of hydrogen fluoride is slow, the concentration of hydrogen fluoride to be added is low, the diffusion rate of hydrogen fluoride in the organic solvent is slow, and the reaction A method such as reducing the speed is preferred. In carrying out the reaction, when the hydrofluoric acid aqueous solution is added rapidly, the reaction advances rapidly, and there is a risk of sudden heat generation and bumping, which is not preferable.

The pressure of the reaction system is not particularly limited, but it is convenient to carry out in the vicinity of normal pressure. Specifically, it is 0.05 MPa or more and 1 MPa or less, preferably 0.05 MPa or more and 0.5 MPa or less, and it is sufficient to carry out in an atmospheric pressure state in which pressure adjustment is not performed.

By the step (b), by-products can be removed, or when hydrogen fluoride is excessively added, unreacted hydrogen fluoride can be removed. That is, holding the reaction solution at an elevated temperature, for example, a temperature higher than the reaction temperature and lower than the reflux temperature of the organic solvent for about 30 minutes to 100 hours is a low-boiling byproduct or an unreacted component, for example, It is effective for removing hydrogen chloride, hydrogen fluoride, carbon dioxide gas, etc. appropriately.

That is, purging by introducing nitrogen gas while stirring the reaction liquid at room temperature or under heating, or refluxing near the boiling point of the solvent, may cause low-boiling by-products or unreacted components such as hydrogen chloride. It is effective for removing hydrogen fluoride, carbon dioxide gas and the like appropriately. In some cases, it may be removed while distillation under reduced pressure. In removing low-boiling acid, it is preferable to adjust the pH to 1 to 4, preferably 2 to 3. By maintaining the pH of the organosol at 1 to 4, it will roughen by reacting with the alkali metal, earth metal, boric acid and silanol groups on the glass surface when the glass substrate is applied, and corroding the surface layer. It is possible to increase the adhesive strength of the coating.

Further, the remaining acid contributes to the stability of the refractive index adjusting material such as metal alkoxide and magnesium hydroxide fluoride, and particularly acts as an acid catalyst, so that a stable mixed solution can be prepared.

In the step (c), the concentration of the liquid containing the magnesium hydroxide fluoride fine particles obtained in the step (b) is adjusted or the solvent is replaced. In order to increase the fine particle concentration, the solvent may be added to lower the fine particle concentration, such as removal of the organic solvent, for example, distillation, extraction, and the like. Further, depending on the application, the solvent may be converted from a solvent used in the production of the organosol to a different solvent.

A step of crushing the organosol may be inserted between step (b) and step (c). For pulverization of organosols, those based on impact force and shear force are effective, and gels or sols that are usually obtained as agglomerates of primary particles can be used as primary particle dispersions. Is particularly preferable.

The magnesium fluorinated magnesium hydroxide is preferably MgF _2-x (OH) _x (x = 0.01 to 0.5). By having an OH group, the adhesiveness to the base material and the hydrophilicity will be superior to simple magnesium fluoride. If x exceeds 0.5, the refractive index may not be kept low. On the other hand, if it is less than 0.01, the number of hydroxyl groups is small, the hydrophilicity becomes small, and the adhesive strength of the film to the substrate may be lowered, which is not preferable.

Among them, magnesium hydroxide fluoride registered in JCPDS file 54-1272, that is, MgF _1.89 (OH) _0.11 is preferably used. This compound is formed even when hydrogen fluoride is dripped more than twice the molar amount of the raw material magnesium compound, and MgF _1.89 (OH) _0.11 is synthesized while leaving hydrogen fluoride in the liquid. Is possible. Even if an excessive amount of hydrogen fluoride is added, MgF _1.89 (OH) _0.11 is produced, and it is considered that there is some equilibrium.

Further, a material obtained by adding calcium fluoride fine particles to the above magnesium hydroxide fluoride fine particles may be used as a raw material for the hydrophilic low reflection film. Calcium fluoride is prepared by coexisting a precursor material such as an alkoxide compound, a halogenated compound, an oxyhalogenated compound, and an acetic acid compound of calcium with the magnesium raw material when preparing fine particles having magnesium hydroxide fluoride. It can be obtained through reaction with.

The amount of calcium fluoride introduced is not particularly limited. Although the refractive index of calcium fluoride is a value that can be used as a low reflection film material, it is slightly higher than magnesium hydroxide fluoride (n = 1.4 to 1.43). Therefore, when a lower refractive index is required, it is better to introduce a smaller amount. Regarding hydrophilicity, 70 mass% or less is more preferable.

For the above reasons, the particle size of the magnesium hydroxide fluoride fine particles is 3 nm or more and 100 nm or less, more preferably 5 nm or more and 60 nm or less, and still more preferably 8 nm or more and 20 nm or less.

[Metal oxide]
By mixing a metal oxide as a refractive index adjusting material into the organosol prepared as described above, the refractive index in the long wavelength region can be lowered, and as a result, low reflectivity and high transmittance can be realized.

Further, by using a metal oxide having conductivity (for example, SnO ₂ or In ₂ O ₃ (ITO) containing Sn) as the metal oxide, an antistatic function can be imparted. Here, SnO ₂ is a semiconductor and exhibits a function as an antistatic film. Here, in order to develop good conductivity, several percent of Sb is added to SnO ₂ as a doping agent, Al ₂ O ₃ is doped to ZnO, and In ₂ O ₃ is similarly applied. SnO ₂ is added.

In addition, since fluorine ions can be an excellent dopant, in the present invention, a good antistatic function has been confirmed even in a form in which each of Sn and In ₂ O ₃ is doped with F ions from several percent to 8%. Furthermore, a combination of both the hydroxyl group of magnesium hydroxide fluoride and the electronic conductivity of the semiconductor has made it possible to realize a long-term stable antistatic function. In the present invention, if a metal oxide having conductivity is used as the refractive index adjusting material, an antistatic function is imparted at the same time while maintaining a low refractive index.

As the refractive index adjusting material, a metal oxide is preferable, and the metal element of the metal oxide may be any metal compound that can finally form an oxide by drying / firing treatment. , Chromium oxide, vanadium oxide, niobium oxide, tantalum oxide provide low reflectivity by the hydrophilic low reflection film of the hydrophilic low reflection base material of the present invention, and the light transmittance of the hydrophilic low reflection base material has a wide wavelength range. Raised in the area.

In addition to the above metal oxides, at least one metal oxide selected from titanium, silicon, zirconium, iron, tin, aluminum, indium, tin, zinc, antimony, lanthanum and the like is used for refractive index adjustment. It is preferable to use it. Furthermore, a borate, a phosphate, etc. can also be used. Among these, when a metal alkoxide, a metal chloride, and its hydrolyzate are used as a raw material, since the intensity | strength and chemical stability of the film | membrane obtained are excellent, it is especially preferable.

The metal oxide is produced by a so-called sol-gel method. In the sol-gel method, a sol composed of a metal compound such as the above-described inorganic salt, organometallic complex, organometallic carboxylate, metal alkoxide and hydrolyzate thereof, or a mixture thereof is used as a raw material. These raw materials (hereinafter sometimes referred to as metal compounds) undergo a reaction such as hydrolysis, dehydration, polycondensation, oxidation, and thermal decomposition in a drying / firing process, whereby a metal oxide is formed by a firing treatment.

When a base material is coated with a sol containing the above metal compound in the presence of magnesium hydroxide fluoride particles and hydrolyzed, a hydrolyzed product of the metal compound is generated. The water required for hydrolysis is supplied from the water in the hydrofluoric acid aqueous solution used for preparing the organosol. Since the sol of the metal compound and the hydrolysis product can react with the hydroxyl group on the surface of the magnesium hydroxide fluoride fine particles, they have a reinforcing function to bond the particles by polycondensation or to bond the particles to the substrate. . Thereafter, as the condensation reaction proceeds, the adhesive strength and friction strength of the resulting film are improved. After that, by forming a film through a drying / firing process, the magnesium hydroxide fluoride particles can be firmly bonded to the base material by the action of a so-called binder.

The following are examples of main metal compounds that are raw materials.

<Tungsten compound>
Examples of the tungsten compound for containing tungsten oxide in the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following.
W (OR) ₆ , W (OR) _(6-n) X _n (wherein R is independently methyl, ethyl, normal propyl, isopropyl, normal butyl, secondary butyl, t- A butyl group, a 2-ethylhexyl group, a methoxyethyl group, a methoxypropyl group, an ethoxymethyl group, an ethoxyethyl group, an ethoxypropyl group, or a phenyl group, and X represents a halogen of F, Cl, Br, or I. In the same manner, calcium tungstate, that is, CaWO ₄ , or iron tungstate, that is, FeWO ₄ , manganese tungstate, after firing by coexisting an alkoxide or tungsten alkoxide with an inorganic or organic salt such as Ca, Fe, or Mn and an alkoxide. That is, a compound that produces a tungstic acid compound of MnWO _4, a tungstic acid as an inorganic salt WO ₃ , its monohydrate, ie WO ₃ .H ₂ O or H ₂ WO ₄ , dihydrate, ie WO ₃ .2H ₂ O or H ₄ WO ₅ , phosphotungstic acid, ie H ₃ [PW ₁₂ O ₄₀ ] · nH ₂ O, heteropolyacid of silicotungstic acid, ammonium metatungstate, ie (NH ₄ ) ₆ [H ₂ W ₁₂ O ₄₀ ] aq, or ammonium paratungstate, ie (NH ₄ ) ₁₀ (H ₂ W ₁₂ O ₄₂ ) · 4H ₂ O.

<Molybdenum compound>
Examples of the molybdenum compound for incorporating molybdenum oxide into the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following.
Mo (OR) ₆ , Mo (OR) _(6-n) _Xn , or molybdenum alkoxide coexisting inorganic / organic salt such as Ca, Fe, Mn and alkoxide and calcining calcium molybdate after firing That is, CaMoO ₄ , iron molybdate, that is, FeMoO ₄ , manganese molybdate, that produces a molybdate compound such as MnMoO ₄ , and ammonium paramolybdate as an inorganic salt, that is, (NH ₄ ) ₁₀ (H ₂ Mo ₁₂ O ₄₂ ) · 4H ₂ O. Molybdic acid, MoO ₃ , its monohydrate, ie, MoO ₃ .H ₂ O, or H ₂ MoO ₄ , dihydrate, ie, MoO ₃ .2H ₂ O or H ₄ MoO ₅ , and phosphomolybdenum as a heteropolyacid Acid, ie H ₃ [PMo ₁₂ O ₄₀ ] · nH ₂ O, ammonium metamolybdate, ie (NH ₄ ) ₆ [H ₂ Mo ₁₂ O ₄₀ ] aq, potassium salt, ie K ₂ MoO ₄ , sodium salt, ie Na ₂ MoO ₄ , ammonium molybdate, tetrabutylammonium salt, ethylenediamine salt, tetramethylammonium salt, or hexa-molybdate.

<Chromium compounds>
The chromium compound for containing the chromium oxide in the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention includes chromium acetate, chromium nitrate, nitric acid hydrate, chromium chloride, chromium chloride hydrate, chromium bromide. , Acetylacetone chromium, benzoyl aceethyl acetone chromium, hexafluoroacetylacetone chromium, chromium naphthenate, chromium phosphate, potassium dichromate, potassium chromate and the like. Furthermore, zinc chromate ZnCrO ₄ , strontium chromate, or SrCrO ₄ may be mentioned.

<Vanadium compounds>
Examples of the vanadium compound for incorporating the vanadium oxide into the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following.
The alkoxide represented by VO (OR) ₃ , as an inorganic salt, vanadium trichloride, ie, VCl ₃ , vanadium dichloride oxide, potassium vanadium trichloride, potassium divanadate, potassium pyrovanadate, potassium vanadate, tetraoxovanadium (V) Potassium acid, Potassium metavanadate, Potassium trioxovanadate (V) Potassium vanadate (II), Tetraoxovanadate (III) Iron (II), Sodium metavanadate, Sodium trioxovanadate (V), Sodium vanadate Sodium tetraoxovanadate (V), sodium divanadate, sodium pyrovanadate, lithium metavanadate, lithium trioxovanadate (V), ie LiVO ₃ , rubidium divanadate, rubidium pyrovanadate, ie Rb ₄ V ₂ O ₇ Rubidium metavanadate: rubidium trioxovanadate (V), ie RbVO ₃ , or rubidium vanadate, eg rubidium tetraoxovanadate (V), ie Rb ₃ VO ₄ .

<Niobium compound>
Examples of the niobium compound for incorporating niobium oxide into the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following.
Nb (OR) ₅ , Nb (OR) _(5-n) _Xn alkoxide, mixed alkoxide with Fe and Mn (Fe, Mn): Nb = 1: 2, niobium pentachloride as inorganic salt.

<Tantalum compound>
Examples of the tantalum compound for containing tantalum oxide in the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following.
Ta (OR) ₅ , Ta (OR) _(5-n) _Xn alkoxide, Fe, Mn mixed alkoxide (Fe, Mn): Ta = 1: 2. Tantalum pentachloride, tantalum pentabromide, tantalum phosphate, tantalum trifluoroethoxide.

<Silicon compound>
Examples of the silicon compound for containing silica of the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following.
Alkoxide is preferable, and is an alkoxy compound represented by the general formula, Si (OR) ₄ or a hydrolyzate thereof, and in particular, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetranormalpropoxysilane, tetranormalbutoxy Silane, tetratertiarybutoxysilane, etc. or a hydrolyzate thereof. In addition, a part of —OR may be substituted with a halogen atom such as a chlorine atom, such as chlorotriethoxysilane, dichlorodinormalbutoxysilane, or trichloronormalbutoxysilane.

<Aluminum compound>
Examples of the aluminum compound for containing alumina in the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following.
Inorganic salts such as aluminum chloride, polyaluminum chloride, aluminum hydroxide such as boehmite, aluminum sulfate, aluminum nitrate, aluminum formate, aluminum acetate, aluminum oxalate, aluminum citrate and other anhydrides and hydrates, organic carboxylic acids As the salt, Al salt such as aluminum laurate, aluminum stearate, aluminum naphthenate, aluminum 2-ethylhexanoate or a hydrated salt thereof.

Examples of the aluminum alkoxide include an alkoxy compound represented by the general formula Al (OR) ₃ , and triethoxyaluminum, triisopropoxyaluminum, trinormalpropoxyaluminum, and trisecondary butylaluminum are particularly preferably used.

Moreover, what substituted a part of (OR) ₃ with halogen atoms, such as a chlorine atom, for example, chlorodiisopropoxy aluminum, chloro disecondary butyl aluminum, dichloro isopropoxy aluminum, and dichloro secondary butyl aluminum can also be used.

The aluminum metal complex is represented by the general formula Al (OR) _n Y _3-n . In the formula, OR represents an alkoxide, and Y represents a ligand. Here, n represents an integer of 0 to 3. Examples of the ligand include acetylacetone (hereinafter sometimes abbreviated as acac), ethyl acetoacetate, methyl acetoacetate, propyl acetoacetate, trifluoroacetylacetone, hexafluoroacetylacetone, methanesulfonic acid, and trifluoromethanesulfonic acid. It is also possible to use a dimer or trimer obtained by condensation polymerization of aluminum alkoxide and these aluminum metal complexes.

<Cerium compound>
Examples of the compound for incorporating cerium oxide into the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following.
Cerium acetate (III) monohydrate, Cerium (III) promide n hydrate, Cerium carbonate (III) n hydrate, Cerium carbonate (III) octahydrate, Cerium chloride (III), Cerium chloride (III ) Heptahydrate, cerium (III) chloride n hydrate, cerium (III) 2-ethylhexanoate, cerium (III) fluoride, cerium fluoride (IV) n hydrate, cerium hydroxide (IV) Cerium (III) bromide, cerium (III) iodide n-hydrate, cerium (III) nitrate hexahydrate, cerium (III) oxalate nonahydrate, 2,4-pentanedionatocerium (III ) N-hydrate, cerium (III) perchlorate hexahydrate, cerium (III) phosphate n-hydrate, cerium silicide, cerium (III) stearate, cerium (III) sulfate n-hydrate, Cerium sulfate (IV) n hydrate, Cerium sulfate (III) pentahydrate, Cerium sulfate (I V) Tetrahydrate, cerium (III) sulfide or ceric ammonium nitrate.

The cerium metal salt is represented by the general formula Ce (OR) _n Y _3-n . In the formula, OR represents an alkoxy group, and Y: represents a ligand or an acid. n: represents an integer of 0 to 3.

Further, chelate complexes such as acetylacetone, ethyl acetoacetate, methyl acetoacetate, propyl acetoacetate, and trifluoroacetylacetone, and examples of the acid include 2-ethylhexanoic acid, methanesulfonic acid, and trifluoromethanesulfonic acid.

<Zirconia compound>
The following are mentioned as a zirconia compound for making a hydrophilic low reflection film of the hydrophilic low reflection member of this invention contain zirconia.
Zirconium tetrachloride, i.e. ZrCl _4, zirconium oxychloride, i.e. ZrOCl _{^_2.} 8H ₂ O, zirconium nitrate, i.e. Zr (NO ₃₎ _4, zirconium oxynitrate, i.e. ZrO (NO ₃₎ ₂ 4 hydrate, zirconium stearate Zr salts such as zirconium naphthenate, zirconium 2-ethylhexanoate, zirconium acetylacetonate, etc., or anhydrous and hydrated salts thereof, or alkoxy compounds represented by the general formula Zr (OR) ₄ .

As such Zr alkoxide, tetraethoxyzirconium, tetranormalpropoxyzirconium, tetraisopropoxyzirconium, tetranormalbutoxyzirconium, and zirconium hydroxide sol which is a hydrolyzate thereof are preferably used.

Further, (OR) ₃ may be partially substituted with halogen, and examples thereof include chlorotriethoxyzirconium, dichlorodinormalbutoxyzirconium, and trichloronormalbutoxyzirconium.

<Titanium compound>
Examples of the titanium compound for containing titania in the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following.
An anhydrous salt such as titanium tetrachloride, ie TiCl ₄ , titanium trichloride, ie TiCl ₃ , titanyl chloride, ie TiOCl ₂ , titanium nitrate, ie Ti (NO ₃ ) ₄ , titanium oxynitrate, ie TiO (NO ₃ ) ₂ Their hydrated salt, titanium 2-ethylhexanoate. Examples of the Ti alkoxide include an alkoxy compound represented by the general formula Ti (OR) ₄ , and tetraethoxytitanium, tetranormalpropoxytitanium, tetraisopropoxytitanium, and tetranormalbutoxytitanium are preferably used. In addition, those polycondensation dimer to 10-mer are also used.

Further, a part of (OR) ₃ may be substituted with a halogen atom such as a chlorine atom. For example, chlorotriethoxytitanium, dichlorodinormalbutoxytitanium, or trichloronormalbutoxytitanium can be used.

The titanium metal complex is represented by the general formula Ti (OR) _n Y _4-n . In the formula, OR represents an alkoxy group, and Y: represents a ligand. n: represents an integer of 0 to 3. Examples of the ligand include acetylacetone, ethyl acetoacetate, methyl acetoacetate, propyl acetoacetate, trifluoroacetylacetone, methanesulfonic acid, and trifluoromethanesulfonic acid.

Further, examples of the chelate compound containing an alkoxy group include dibutoxy titanium bisacetylacetonate and isopropoxy dititanium bisoctylene glycolate.

<Tin compounds>
Examples of the tin compound for containing tin oxide in the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following.
In addition to tin chlorides such as tin dichloride, ie SnCl ₂ , tin tetrachloride, ie SnCl ₄ , tin alkoxides such as tetraethoxytin, tetranormalpropoxytin, tetraisopropoxytin, tetranormalbutoxytin, and Sn (OiPr) ₃ (acac), Sn (OnBu) ₃ Cl, BuSnCl ₃ and Bu ₂ Sn (acac) ₂ . SnO ₂ is a semiconductor and imparts an antistatic function to the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention.

<Indium compound>
Examples of the indium compound for incorporating indium oxide into the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following. Indium trichloride, indium trichloride tetrahydrate, indium bromide, indium iodide, indium nitrate trihydrate, indium acetate, indium sulfate n-hydrate, indium perchlorate octahydrate, indium phosphate, etc. These inorganic indium salts and indium metal salts are represented by the general formula In (OR) _n Y _3-n . In the formula, OR represents an alkoxy group, and Y: represents a ligand or an acid. n: represents an integer of 0 to 3.
Specific examples of the ligand include acetylacetone, ethyl acetoacetate, methyl acetoacetate, propyl acetoacetate, and trifluoroacetylacetone, and examples of the acid include 2-ethylhexanoic acid, methanesulfonic acid, and trifluoromethanesulfonic acid.

In addition to indium alkoxides such as tetramethoxyindium, tetraethoxyindium, tetranormalpropoxyindium, tetraisopropoxyindium, and tetranormalbutoxyindium, In (OMe) ₂ Cl, In (OEt) ₂ Cl, In (OiPr) ₂ Cl, Examples thereof include halogenated alkoxides such as In (OnBu) ₂ Cl, In (OiPr) ₂ Cl, and In (OnBu) ₂ Cl.

<Zinc compound>
Examples of the zinc compound for containing zinc oxide in the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following. Zinc chloride, zinc bromide, zinc iodide, zinc nitrate trihydrate, zinc acetate dihydrate, zinc sulfate heptahydrate, zinc phosphate, zinc borate, zinc perchlorate hexahydrate, etc. Inorganic zinc compounds, zinc stearate, zinc benzoate, zinc phenolsulfonate, zinc salicylate, zinc pyrithione, zinc acetylacetonate hydrate, ethyl zinc acetoacetate hydrate, methyl zinc acetoacetate, propylzinc acetoacetate, tri Examples include zinc fluoroacetylacetonate, zinc 2-ethylhexanoate, zinc methanesulfonate, zinc trifluoromethanesulfonate, tetramethoxyzinc, tetraethoxyzinc, tetranormalpropoxyzinc, tetraisopropoxyzinc or tetranormalbutoxyzinc.

<Antimony compound>
Examples of the antimony compound for containing antimony oxide in the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following. Antimony (III) acetate, antimony acetate dihydrate, antimony (III) bromide, antimony (III) butoxide, antimony (III) chloride, antimony (IV) tetrachloride, antimony bromide, antimony (III) Examples include ethoxide, antimony (III) fluoride, antimony (V) tetrafluoride, antimony zinc tetratetrachloride, antimony zinc tetranormal propoxyantimony trichloride, zinc antimony tetraisopropoxy trichloride, or zinc zinc tetranormalbutoxy.

<Lanthane compound>
Examples of the lanthanum compound for containing lanthanum oxide in the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention include the following. Lanthanum chloride, lanthanum chloride hexahydrate, lanthanum chloride heptahydrate, lanthanum bromide, lanthanum bromide heptahydrate, lanthanum iodide, lanthanum nitrate hexahydrate, lanthanum acetate n-hydrate, lanthanum sulfate 9 Hydrate, Lanthanum phosphate n-hydrate, Lanthanum perchlorate hexahydrate, Lanthanum oxalate 9-hydrate, Lanthanum ethylhexanoate, Acetylacetonate lanthanum hydrate, Ethyl lanthanum acetoacetate hydrate , Methyl lanthanum acetoacetate, trifluoroacetylacetonate lanthanum trifluoromethane, lanthanum methanesulfonate, lanthanum trifluoromethanesulfonate, tetramethoxylanthanum, tetraethoxylanthanum, tetranormalpropoxylantan, tetraisopropoxylantane or tetranormalbutoxylantan .

[Metal compound organosol]
As described above, an organosol of metal oxide produced by solvent substitution of oxide fine particles obtained by hydrolyzing basic chloride or metal alkoxide can be obtained as a commercial product.

For example, organosilica sol is available from Nissan Chemical Industries, Ltd. under the trade name, methanol silica sol, IPA-ST, IPA-ST-UP, IPA-ST-ZL, EG-ST, NPC-ST-30, DMAC-ST, MEK. -Product names, Oscar 1132, Oscar 1232, and Oscar 1332 are commercially available from ST, JGC Catalysts & Chemicals Co., Ltd. Organoalumina sols are commercially available from Kawaken Fine Chemical Co., Ltd. under the trade names of Aluminum Sol-CSA55 and Aluminum Sol-CSA110AD. Further, organic solvent-based antimony oxide sols are commercially available from Nissan Chemical Industries, Ltd. under the trade names Sun Colloid ATL-130 and Sun Colloid AMT-130.

Alternatively, a commercially available sol as an aqueous dispersion can be used after solvent substitution.
Such aqueous sols are commercially available from Nissan Chemical Industries, Ltd. under the trade names, Snowtex 40, Snowtex O, Snowtex C, Snowtex N, and from JGC Catalysts & Chemicals, Inc. -30H, Cataloid SI-30, Cataloid SN, Cataloid SA are commercially available from Asahi Denka Kogyo Co., Ltd. under the trade names Adelite AT-30, Adelite AT-20N, Adelite AT-20A, Adelite AT-20Q, The trade names “Silica Dole-30”, “Silica Doll-20A”, and “Silica Doll-20B” are commercially available from Nippon Kagaku Kogyo Co., Ltd. 200, alumina sol-520 is commercially available. The trade name, Alumina Clear Sol, Aluminum Sol-10, Aluminum Sol-20, Aluminum Sol SV-102, and Aluminum Sol-SH5 are commercially available from Fine Chemical Co., Ltd. 1550 and A-2550 are commercially available. Aqueous zirconium oxide sol is commercially available from Nissan Chemical Industries, Ltd. NZS-30A and NZS-30B. Aqueous tin oxide sol is available from Taki Chemical Co., Ltd. -8, Cerames C-10 is commercially available, and water-based titanium oxide sols are commercially available from Taki Chemical Co., Ltd. under the trade names Tynock A-6 and Tynock M-6, and water-based sols composed of tin oxide and antimony oxide are The trade name Cerames F-10 is commercially available from Taki Chemical Co., Ltd.

[Coating solution]
The coating solution applied to the transparent substrate is important for long-term stability and is preferably stored at room temperature for 30 days or more. When the above hydrolyzable metal compound is added to the magnesium hydroxide fluoride dispersion (sol), if the mixture of only one metal compound cannot reduce the refractive index of the target wavelength, 2-4 It is necessary to add a seed metal compound. In such mixing, even when there is only one kind of metal compound, even if it can exist as a relatively stable dispersion (sol), if the compatibility of the mixed metal compound does not match, there is a possibility of gelation. is there.

In addition, when comparing the stability of metal oxide precursors in the dispersion (sol), such as metal alkoxides, Si-based alkoxides such as alkoxysilanes are relatively stable, but Al-based, Zr-based, Ti-based It is known to those skilled in the art that Sn-based and Ta-based alkoxides are unstable. Patent Document 4 describes a mixed system of magnesium fluoride and an Al-based alkoxide in Example 3, and a mixed system of Zr alkoxide in Example 4, which uses acetylacetone as a complexing agent and passes through a syringe filter. The transparent sol is manufactured by this method. When the present inventors made additional trials with respect to Example 3 and Example 4, the coating solution could only exist stably for one day at room temperature, and the viscosity increased rapidly, which was not suitable as a coating solution. .

Furthermore, with reference to the example of Patent Document 4, an additional test was conducted in a system in which three types of alkoxides of Si alkoxide, Al alkoxide, and Zr alkoxide were added to magnesium fluoride. When stability was confirmed, it was mixed with MgF ₂ . When the mixed metal oxide sol is mixed with MgF ₂ , the polymerization starts rapidly, the viscosity rapidly increases, and after 2 days, it completely gels and is not practically usable and lacks stability as a coating solution. It was.

The coating solution for the hydrophilic low reflection film of the hydrophilic low reflection member of the present invention was a mixture of a magnesium hydroxide fluoride sol and at least one metal oxide, and was extremely stable. Further, in the coating solution for the hydrophilic low-reflection film coated on the hydrophilic low-reflection member of the present invention, magnesium hydroxide fluoride has good compatibility with inorganic salts, organic salts, and metal alkoxides. there were.

The raw material hydrogen fluoride and by-product acid such as HCl are intentionally left during preparation of the magnesium hydroxide fluoride sol, but the remaining 0.5% or more and 3% or less (in terms of F and HCl) Is considered to be useful as a peptizer for metal compounds such as metal alkoxides, and long-term stability of 30 days or more at room temperature was confirmed even when 4 to 5 types of metal alkoxides were added.

As a preferred embodiment, when magnesium chloride is used as a magnesium source and directly reacted with a slight excess of hydrogen fluoride, HCl is generated as a by-product. Hydrogen fluoride and HCl have a high vapor pressure, and can be easily removed by heating or bubbling, so that HCl can remain in a few percent.

[Transparent substrate]
As the transparent substrate, an inorganic glass substrate such as a glass plate or a plastic substrate such as a plastic plate can be used.

Examples of inorganic glass substrates include plate-like materials such as soda lime silicate glass, borosilicate glass, aluminosilicate glass, barium borosilicate glass, and quartz glass, especially those manufactured by the float process. Can do. Furthermore, these glass substrates also use clear glass products, colored glass products such as green and bronze, functional glass products such as UV and IR cut glass, and safety glass products such as tempered glass, semi-tempered glass, and laminated glass. Can be done. Moreover, as ceramics, substrates such as Si ₃ N ₄ , SiC, sapphire, Si wafer, GaAs, InP, and AlN can be used.

Examples of the plastic substrate include polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), triacetyl cellulose (TAC), polyimide, and the like.

[Coating method]
The coating method of the coating solution on the substrate is a wet coating method, which is a spin coater method, a dip-up method, that is, a dip coating method, a spray method, a roller coating method, a flow coating method, a screen printing method, a brush coating, or an inkjet. Law.

[Hydrophilic low reflective film]
It is preferable that the film formed by the various methods is dried by heating at 80 ° C. or higher and 150 ° C. or lower for 10 minutes to 6 hours, and then further heated and fired. The heating temperature is determined according to the heat-resistant temperature of the substrate. In addition, when taking advantage of the characteristics of magnesium hydroxide fluoride, it is preferable to fire in a temperature range in which characteristics such as hydrophilicity can be maintained. In the case of a plastic substrate, it is preferable to perform the treatment at about 300 ° C. or less. In addition, the inorganic glass substrate can be fired at a high temperature of about 700 ° C. by adjusting the firing time. As a preferred embodiment, a film having excellent wear resistance was obtained by baking at 650 ° C. or higher and 700 ° C. or lower for a few minutes, that is, 120 seconds to 180 seconds.

In the coating, the metal oxide has a size equivalent to that of magnesium hydroxide fluoride of 3 nm or more and 100 nm or less, more preferably 5 nm or more and 60 nm or less, and further preferably 8 nm or more and 20 nm or less. It is preferably present as a binder for binding magnesium halide.

The preferable film thickness of the hydrophilic low reflection film on the transparent substrate surface of the hydrophilic low reflection member of the present invention is 20 nm or more and 500 nm or less. If the film thickness is less than 20 nm, the wear resistance is poor and film formation is difficult. On the other hand, if it is thicker than 500 nm, the film thickness becomes non-uniform and it is difficult to form a film. Preferably, they are 50 nm or more and 150 nm or less. In order to obtain a low reflectance with respect to visible light, the thickness is preferably 100 nm or more and 120 nm or less.

The contact angle shall be defined from the contact angle between the surface of the coating layer obtained in accordance with JIS R 3257 (1999) and water droplets. It is considered that the higher the wettability, the better the hydrophilic low reflection film, and the contact angle is preferably 30 ° or less. More preferably, it is 20 ° or less. Since it has hydrophilicity, it is excellent in antifouling property and can be easily washed away even when dirt is attached.

The hydrophilic low reflection member of the present invention has a surface resistance value of 1 × 10 ¹⁰ Ω. Since it is cm or less, it is a hydrophilic low reflection member having an antistatic function.

These hydrophilic low reflection films are formed on one side or both sides of the transparent substrate. When both surfaces of the transparent substrate are used in contact with a medium having a refractive index close to 1 such as air, a high antireflection effect can be obtained by forming this film on both surfaces of the substrate.

[Hydrophilic low reflection member]
The hydrophilic low reflection member of the present invention is useful as a surface protection member of a solar cell, for example, a solar cell cover glass. When used as a solar cell cover glass, high light transmittance and low reflectance are required, and since solar cells are constantly exposed to sunlight, they have antifouling properties, water resistance, weather resistance, etc. A material is desired. As described above, the hydrophilic low reflection film of the present invention containing magnesium hydroxide fluoride is excellent in antifouling property, water resistance and weather resistance.

In addition, CIS thin-film solar cells and crystalline silicon, which have been developed in recent years, have a wide absorption of wavelengths of 380 nm or more and 2000 nm or less, and light in a longer wavelength range than conventional amorphous silicon systems. The absorption peak is in the vicinity of 900 nm. As described above, the hydrophilic low-reflection film of the present invention has high light transmittance in the ultraviolet / visible light wavelength region, 380 nm or more and 800 nm or less, and the near infrared wavelength region, 800 nm or more and 2000 nm or less. It can be suitably used as a surface protection member for solar cells having absorption in a long wavelength region as well as amorphous silicon solar cells.

Hereinafter, based on an Example, the hydrophilic low reflection member of this invention is demonstrated.
Various low reflective films were coated on a soda lime silicate glass substrate and evaluated for physical properties.
The physical property evaluation method is shown below.

1. Optical properties (transmittance, reflectance) were measured using a spectrophotometer U-4100 manufactured by Hitachi, Ltd.
2. The surface resistance value was measured using an insulation resistance measuring instrument 4329A high resistance meter manufactured by Yokogawa Electric Corporation.
3. The refractive index was measured at 637 nm using a spectroscopic ellipsometer UVISEL-ER manufactured by Horiba, Ltd.
4). The film thickness was measured with a stylus type surface shape measuring instrument (ULVAC, Inc., product number, Dektak V200 Si / SL, the same shall apply hereinafter). The contact angle was measured according to JIS R 3257 (1999) using a pure water contact angle measuring device manufactured by Kyowa Interface Science Co., Ltd.

Example 1
<Preparation of magnesium hydroxide fluoride sol>
Into a 5 L three-necked flask, 184.6 g (1.94 mol) of reagent-grade magnesium chloride was added, 3905 g of methanol was added, and the mixture was stirred at room temperature for 3 hours to obtain a colorless and transparent magnesium chloride solution. While stirring 159.2 g (4.38 mol) of a 55% by mass hydrofluoric acid aqueous solution into the above magnesium chloride solution at room temperature, the hydrogen fluoride / Mg = 2.26 molar ratio was intermittently obtained. It was dripped. After stirring at room temperature for 3 hours, a colorless and transparent sol that was a dispersion of magnesium hydroxide fluoride fine particles was obtained. After drying, magnesium hydroxide fluoride was obtained as identified by X-ray analysis.

Next, while bubbling while blowing dry nitrogen into the sol at a rate of 2 L / min, while warming to about 58 ° C., HCl and excess hydrofluoric acid as by-products were degassed and concentrated. Bubbling for about 5 hours removed 385 g of methanol, HCl and hydrofluoric acid. As a result of analysis by ion chromatography, the residual acid content was 3.2% by mass as Cl ⁻ ions and 0.65% by mass as F ⁻ ions. To adjust the concentration, isopropyl alcohol (hereinafter abbreviated as IPA) was added, and the solid content concentration of magnesium hydroxide fluoride was adjusted to 3.5% by mass.

<Preparation of coating solution>
120 ml of the magnesium hydroxide fluoride sol synthesized above is collected, and a Wako Pure Chemical Industries, Ltd. reagent, Al (OsBu) _3, is added as a metal compound to 2% by mass in terms of Al ₂ O _3. 30 ml of the ethanol solution prepared as described above was added, and the reagent, W (OiPr) ₆ , was added to 2% by mass in terms of WO ₃ , and IPA was added with stirring in 30 ml and stirred at 60 ° C. for 16 hours. As a result, a light brown coating solution was obtained. Note that sBu is an abbreviation for sec butoxy group, and iPr is an abbreviation for isopropoxy group (hereinafter the same).

<Application>
After dipping, a soda lime silicate glass substrate having a thickness of 3 mm and a size of 100 mm × 100 mm was dipped in the coating solution, then pulled up at a speed of 4.5 mm / sec, and applied to both surfaces of the glass substrate. Dry at 30 ° C. for 30 minutes. The glass substrate was put into an electric furnace at 750 ° C., held for 150 seconds, and taken out to obtain a coating film having a blue-violet reflection color on the glass substrate surface.

In this way, the content of the refractive index adjusting agent is 1.7 per 10 mol of magnesium hydroxide fluoride, that is, magnesium hydroxide fluoride: (tungsten oxide + alumina) = 10: 1.7. A reflective film was obtained. The film thickness was 105 nm as measured by a stylus type surface shape measuring instrument (ULVAC, Inc., product number, Dektak V200 Si / SL, the same applies hereinafter).

FIG. 1 shows a scanning electron microscope (SEM) photograph of a glass substrate on which a film is formed.

When the average transmittance in the wavelength range of 380 nm to 780 nm was measured, the average was 98.1%, which was compared with the average transmittance of 90.4% of an untreated glass substrate (base plate: Blank) on which no film was formed. The transmittance was improved by 7.7%.

The refractive index was n = 1.286 at a wavelength of 637 nm when measured in the range of 190 nm to 2100 nm using a spectroscopic ellipsometer “UVISEL-ER” manufactured by Horiba, Ltd.

In the appearance inspection after this coating was rubbed 500 times with a load of 300 g using a dry flannel, slight scratches were observed, but the optical characteristics were hardly changed. Further, when the contact angle with pure water was measured, it showed excellent hydrophilicity at 6.5 °.

When this film was exposed outdoors at an inclination of 45 °, the pure contact angle was 12.4 ° even after 6 months, showing hydrophilicity, and the change in haze value was + 0.51%. Maintained sex and self-cleaning function.

Further, when the surface resistance value of this film after being left for 30 days in an environment of 25 ° C. and 50% relative humidity was measured, it was 6.9 × 10 ⁸ Ω · cm, and it was confirmed that it had excellent antistatic performance ^. It was.

Example 2
140 ml of the magnesium hydroxide fluoride sol synthesized in Example 1 was collected, and H. as a metal oxide was added thereto. C. Stark's high-purity product AMPERTEC reagent Ta (OEt) ₅ for the semiconductor and electronics industries is added with 30 ml of ethanol solution adjusted to 2.4% by mass in terms of Ta ₂ O ₅ with stirring, and colloidal silica. As a commercially available product of JGC Nippon Shokubai Co., Ltd., trade name, OSCAL1432, 35 ml of an ethanol solution prepared so as to be 1.6% by mass in terms of SiO ₂ was added and stirred at 60 ° C. for 16 hours. A coating solution was obtained. OEt is an abbreviation for ethoxy group (hereinafter the same).

Adopting a dip method, a soda lime silicate glass substrate having a thickness of 3 mm and a size of 100 mm × 100 mm was immersed in the coating solution, then pulled up at a rate of 5.3 mm / sec, and applied to both surfaces of the glass substrate. It was dried at 100 ° C. for 30 minutes. The glass substrate was taken out by holding it in an electric furnace at 520 ° C. for 1.5 hours for 1 hour to obtain a blue-violet transparent film.

Thus, a hydrophilic low-reflection film having a refractive index adjusting agent content of molar ratio of magnesium hydroxide fluoride: (tantalum oxide + silica) = 10: 1.9 was obtained. The film thickness was 108 nm as measured by the stylus type surface shape measuring instrument.

FIG. 2 shows a scanning electron microscope (SEM) photograph of the glass substrate on which the film is formed.

FIG. 3 shows a transmittance curve of a glass substrate on which a film is formed. Not only the visible light region but also the near infrared region has excellent transmittance.

As shown in the light transmittance curve (Example 2) of FIG. 3, when the average transmittance in the wavelength range of 380 nm to 780 nm was measured, the average was 98.2%, and an untreated glass substrate (base plate: Blank) ) And the average transmittance of 90.5% were 7.7% larger, and the transmittance was greatly improved.

The refractive index, when measured in the range of 190 nm to 2100 nm using a spectroscopic ellipsometer UVISEL-ER manufactured by Horiba, Ltd., was n = 1.291 at a wavelength of 637 nm.

In the appearance inspection after the coating was rubbed 1000 times with a load of 300 g using a dry flannel, some scratches were observed, but the optical characteristics were not changed. Moreover, when the pure water contact angle was measured, it showed super hydrophilicity at 4.8 °.

When this film was exposed outdoors at an inclination of 45 °, the pure water contact angle was 10.7 ° even after 6 months, and it showed hydrophilicity, and the change in haze value was + 0.4% with almost no contamination. Maintained hydrophilicity and self-cleaning function.

The film was left indoors for 120 days, and the surface resistance value measured under an environment of 21 ° C. and 22.5% relative humidity was 3.3 × 10 ⁹ Ω · cm. Excellent hydrophilic performance was obtained. It was confirmed to have.

When the Auger analysis was performed while etching the hydrophilic low reflection film formed on the surface of the hydrophilic low reflection member of this example using tantalum oxide, the fluorine content gradually decreased in the depth direction. The tantalum content gradually increased. Furthermore, oxygen and silicon increased rapidly and tantalum and fluorine disappeared completely at the boundary surface between the hydrophilic low-reflection film and the glass plate as the transparent substrate.

Example 3
120 ml of the magnesium hydroxide fluoride sol synthesized in Example 1 was collected. 25 ml of a liquid prepared by adding IPA as a metal oxide to Niobium Isopropoxide Nb (OiPr) ₅ by 2.2% by mass in terms of Nb ₂ O ₅ as a metal oxide In addition, with stirring, 25 ml of an ethanol solution prepared by adjusting Wako Pure Chemical Industries, Ltd. reagent, Al (OsBu) ₃ to 2.0 mass% in terms of Al ₂ O ₃ , was added at 60 ° C. The mixture was stirred for 16 hours to obtain a colorless and transparent coating solution.

Adopting a dip method, a 100 mm × 100 mm × 3 mm soda lime glass substrate is immersed in the coating solution, then pulled up at a speed of 6.0 mm / sec, applied to both surfaces of the glass substrate, and then dried at 100 ° C. for 30 minutes. I let you. The glass substrate was taken out in an electric furnace at 520 ° C. while being heated for 1.5 hours for 1 hour to obtain a coating film having a blue-violet reflection color.

In this manner, a hydrophilic low reflection film having a molar ratio of magnesium hydroxide fluoride: (niobium oxide + alumina) = 10: 1.9 was obtained. The film thickness was 111 nm as measured by a stylus type surface shape measuring instrument.

FIG. 4 shows a scanning electron microscope (SEM) photograph of the glass substrate on which the film is formed.

FIG. 5 shows a transmittance curve of a glass substrate on which a film is formed. Not only the visible light region but also the near infrared region has excellent transmittance.

As shown in the light transmittance curve (Example 3) of FIG. 5, when the light transmittance in the wavelength range of 380 nm to 780 nm was measured, the average transmittance was 97.7%, and no coating was formed. Compared with the average transmittance of 90.2% of the glass substrate (base plate: Brank), the transmittance was improved by 7.5%.

The refractive index was measured with a spectroscopic ellipsometer UVISE-ER manufactured by Horiba, Ltd., and the wavelength was 637 m and n = 1.310.

In the appearance inspection after the coating was rubbed 1000 times with a load of 300 g using a dry flannel, some scratches were observed, but the optical characteristics were not changed. Moreover, when the pure water contact angle was measured, it showed excellent hydrophilicity at 4.0 ° or less.

When this film was exposed outdoors at an inclination of 45 °, the pure contact angle was 9.6 ° even after 6 months, and it was hydrophilic, and the change in haze value was + 0.9%. Maintained sex and self-cleaning function.

The film was left indoors for 120 days, and the surface resistance value measured under an environment of 21 ° C. and 22.5% relative humidity was 6.0 × 10 ⁸ Ω · cm ^. It was confirmed to have.

According to Examples 1 to 3, the hydrophilic low-reflection film of the present invention is excellent in all of the effects of low reflection, hydrophilicity and antifouling, has antistatic performance, and is highly resistant to low dirt. Obviously, it becomes possible to obtain a membrane.

According to the present invention, a hydrophilic low reflection member having a hydrophilic low reflection film having a durable hydrophilic and low refractive index formed on the surface was obtained. The hydrophilic low-reflection member of the present invention includes optical materials such as lenses, image display surfaces such as cathode ray tubes and liquid crystal display devices, windows and showcases, skylight materials, solar cells, water heaters, lighting devices, etc. It can be used in a wide range of fields where hydrophilicity, antifouling properties, and low reflection antistatic properties are required. Moreover, since it is excellent not only in the ultraviolet to visible wavelength range but also in the near-infrared wavelength range, it is useful as a solar cell surface protective member, particularly a solar cell cover glass.

Claims

A hydrophilic low-reflection member having a transparent substrate and a hydrophilic low-reflection film formed on the surface thereof, wherein the hydrophilic low-reflection film comprises magnesium hydroxide fluoride fine particles and tungsten oxide as a refractive index adjusting material. And at least one metal oxide selected from the group consisting of molybdenum oxide, chromium oxide, vanadium oxide, niobium oxide and tantalum oxide, and has a refractive index of 1.23 or more and 1.41 or less. A hydrophilic low reflection member characterized by the above.
The hydrophilic low-reflection member according to claim 1, wherein the magnesium hydroxide fluoride is MgF 2-x (OH) x (x = 0.01 to 0.5).
3. The hydrophilic low reflection film according to claim 1, wherein the molar ratio of the refractive index adjusting material to the magnesium hydroxide fluoride is in the range of 0.5: 10 to 30:10. The hydrophilic low reflection member as described.
The hydrophilic low-reflective film is at least one selected from the group consisting of silica, alumina, ceria, zirconia, titania, tin oxide, indium oxide, zinc oxide, antimony oxide and lanthanum oxide as a refractive index adjusting material. The hydrophilic low reflection member according to any one of claims 1 to 3, wherein the hydrophilic low reflection member comprises:
The average transmittance of the hydrophilic low-reflection member in the wavelength range of 380 nm or more and 2000 nm or less is 6% or more higher than the average transmittance of the transparent substrate in the same wavelength range. The hydrophilic low-reflection member according to any one of the above.
The hydrophilic low reflection member according to any one of claims 1 to 5, wherein a contact angle of water on the surface of the hydrophilic low reflection film is 30 ° or less.
Wherein a surface resistance value of the hydrophilic low-reflection film surface is not more than 1 × 10 10 Ω. Cm, hydrophilic low-reflection member according to any one of claims 1 to 6.
A surface protection member for a solar cell, wherein the hydrophilic low reflection member according to any one of claims 1 to 7 is used.
A coating solution containing magnesium hydroxide fluoride fine particles and at least one metal compound selected from the group consisting of tungsten, molybdenum, chromium, vanadium, niobium and tantalum is applied to the surface of the transparent substrate and then baked. The method for producing a hydrophilic low-reflection member according to any one of claims 1 to 8, wherein
Magnesium hydroxide fluoride fine particles, at least one metal compound selected from the group consisting of tungsten, molybdenum, chromium, vanadium, niobium and tantalum, silicon, aluminum, cerium, zirconium, titanium, tin, indium, The coating liquid in which at least one metal compound selected from the group consisting of zinc, antimony and lanthanum is dispersed is applied to the surface of the transparent substrate and then baked. The manufacturing method of the hydrophilic low-reflection member of description.