JPH0688779B2 - Method of manufacturing MgF film 2 and method of manufacturing low reflection film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a method for producing an MgF ₂ film and a method for producing a low reflection film according to the present invention.

[Prior Art] The coating method of a low-reflection film has been studied so far not only in optical equipment but also in consumer equipment, particularly in televisions and cathode ray tubes (CRTs) of computer terminals.

The conventional method is, for example, as described in JP-A-61-118931, to attach an SiO ₂ layer having fine irregularities on the surface in order to have an antiglare effect on the surface of the cathode ray tube, or to etch the surface with hydrofluoric acid to form irregularities. Methods such as installation have been adopted. However, these methods are called non-glare processing for diffusively reflecting external light, and since there is essentially no method of providing a low reflection layer, there is a limit in reducing the reflectance.

Attempts have also been made to attach MgF ₂ , which is a stable low-refractive index substance, to lenses and glass surfaces by physical means such as vacuum deposition, but this method requires high equipment costs, or
There is a drawback that it is difficult to store a large adherend such as a CRT completed sphere in the vacuum chamber.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a method for producing a MgF ₂ film having a simple, stable and excellent low reflection property by a chemical method. By providing new.

[Means for Solving the Problems] That is, the present invention is based on MgX ₂ (X = halogen element excluding fluorine).
And a liquid containing BF ₃ complex salt is applied onto a substrate and then heated to produce an MgF ₂ film, and a method for producing an MgF ₂ film, and a single layer or a multilayer film on the substrate, of which: in the method at least more to form a low reflection film which is a MgF ₂ film, after the MgF ₂ film was coated with a liquid containing and BF ₃ complex (halogen excluding X = fluorine) MgX ₂ on the substrate,
The present invention newly provides a method for producing a low reflection film, which is characterized by being formed by heating.

As a fluorinating agent (halogen excluding X = fluorine) MgX ₂ in the present invention, MgF ₂ by BF ₃ complex which acts
Is believed to be produced, and this reaction proceeds easily by dispersing or dissolving the MgX ₂ and BF ₃ complex salt starting materials in a solvent and further heating.

3MgX ₂ + 2BF ₃ → 3MgF ₂ + 2BX ₃ ↑ (1) As starting material MgX ₂ , MgCl ₂ , MgBr ₂ , MgI _{2 and the} like can be used, but MgCl ₂ is a reaction of the above formula (1). Is most preferable because it proceeds most easily.

Further, as the BF ₃ complex salt, various ones can be used, preferably alkyl ether complex salt, alcohol complex salt, aqueous solution complex salt, particularly preferably ethyl ether complex salt, methanol complex salt, ethanol complex salt, acetic acid complex salt. .

The solvent is not particularly limited, but water, aqueous solution, alcohol, ester, ether, or organic high dielectric constant solvent such as propylene carbonate or γ-butyrolactone can be used.

Considering the stability of the starting material in a solvent, the solvent is preferably alcohol, particularly methanol, ethanol, propanol or butanol.

The starting material preferably has a molar ratio of MgX ₂ and BF ₃ complex salt in the range of 1: 2 to 4: 1, particularly in the range of 1: 1 to 2: 1, and the starting material is 1 to 30 wt% with respect to the solvent. It is preferably included.

Further, the solution used in the present invention contains Si (OR) ₄ (R: as a binder in order to improve the adhesion strength and hardness of the film.
Alkyl group) etc. are added to precipitate SiO ₂ at the same time,
Various kinds of surfactants can be used as the surfactant for improving the wettability with the substrate. For example, sodium linear alkylbenzene sulfonate, alkyl ether sulfate, etc. may be added.

Acetylacetonate of a metal (for example, Sn, In, etc.) capable of forming a conductive metal oxide (for example, SnO ₂ , In ₂ O ₃ (ITO) containing Sn, etc.) for the purpose of imparting conductivity. ,
Organic metal salts such as alkoxides, halides, acetates,
A metal salt such as a nitrate or a chelate compound is added to a liquid containing MgX ₂ and a BF ₃ complex salt used in the present invention, and SnO ₂
It is also possible to simultaneously deposit In ₂ O ₃ (ITO) containing Sn or Sn.

The heating temperature needs to be 50 ° C. or higher, but the upper limit is usually determined by the softening point of the glass, plastics, etc. used for the substrate. Considering this point, the preferable temperature range is 100 to 400 ° C.

The method for depositing the film on the substrate is spin coating, dipping,
Although various methods such as a spray method, a roll coater method, and a meniscus coater method can be considered, the spin coating method is particularly preferable because it is excellent in mass productivity and reproducibility. By this method, it is possible to form an MgF ₂ film having a film thickness of about 100Å to 1 μm.

In the present invention, the substrate forming the low reflection film containing MgF ₂ film and MgF ₂ is not particularly limited, depending on the purpose, soda lime silicate glass, aluminosilicate glass, borosilicate glass, lithium aluminosilicate. Glass, glass such as quartz glass, single crystal such as corundum, translucent ceramics such as magnesia and sialon,
Plastics such as polycarbonate can be used.

The method for producing a MgF ₂ film of the present invention can be applied to the production of a multilayer low reflection film containing a MgF ₂ film. As the structure of the multilayer low-reflection film having antireflection performance, the wavelength to be antireflection is set to λ, and the high refractive index layer-low refractive index layer is formed with an optical thickness of λ / 2-λ / 4 from the substrate side. The low reflection film of the layer, the medium refractive index layer-high refractive index layer-low refractive index layer from the substrate side to the optical thickness λ / 4-λ / 2
-Three-layer low-reflection film formed with λ / 4, lower refractive index layer than substrate-medium refractive index layer-high refractive index layer-low refractive index layer with optical thickness λ / 4
A four-layer low reflection film formed of −λ / 4−λ / 2−λ / 4 is known as a typical example, and in the present invention, a MgF ₂ film (n = 1.38) is used as the low refractive index layer. It is also possible to manufacture a multilayer low reflection film using

In addition, as a solution to the problem pointed out in cathode ray tubes (CRTs) and front panels, etc., where the surface is charged by static electricity generated during CRT operation and discharge between human body and dust is easily adsorbed. It is known that one layer of the low reflection film is made of a transparent and conductive material, but it can also be applied to the production of such a low reflection film having conductivity. For example, the substrate / SnO ₂ / MgF _2, a low-reflection film such as substrate / ITO / MgF ₂ can be formed.

Example 1 Example 1 MgCl ₂ and BF ₃ MeOH complex salt were added and dissolved in a molar ratio of 3: 2 and a total amount of 5% by weight based on the solvent.

A glass substrate was dip-coated in this solution and further coated with a spin coater at a rotation speed of 3000 rpm. The glass substrate was baked in air at 250 ° C. for 30 minutes to form a 960Å MgF ₂ film, and then the reflectance on the other side at a wavelength of 360 to 700 (nm) was measured.

Example 2 An MgF ₂ film (1150Å) was formed in the same manner as in Example 1 except that the firing temperature was 150 ° C.

Example 3 A MgF ₂ film (thickness: 1000) was prepared in the same manner as in Example 1 except that a solvent was methanol butanol (volume ratio 1: 1).
Å) formed.

Example 4 Example 1 except that the rotation speed of the spin coater was 300 rpm.
A MgF ₂ film (film thickness 120Å) was formed in the same manner as in.

Example 5 SnC was added to a solvent consisting of methanol and water (volume ratio 1: 1).
l ₄ and SbCl ₃ were added to a solvent so that each of them would be 2,0.2 wt% and dissolved, and a glass substrate was dipped and coated on the solution, which was further coated with a spin coater at 3000 rpm, and then in air.
It was baked at 00 ° C. for 300 minutes to form a 1100Å SnO ₂ film. Next, the same method as in Example 1 was applied to coat 960Å MgF ₂
A film was formed.

Comparative Example The reflectance of an untreated glass substrate was measured as in Example 1.

As the measurement results of Examples 1 to 5 and Comparative Example, a wavelength of 520 (n
Table 1 shows the reflectance at m).

EFFECTS OF THE INVENTION According to the present invention, a liquid containing MgX ₂ and BF ₃ complex salt is sprayed or spin-coated on a substrate, or a simple method such as immersing the substrate in the liquid is used to efficiently and excellently produce MgF. ₂
It is possible to provide a low reflection film including a film and an MgF ₂ film.

The present invention is excellent in productivity and does not require a vacuum, so that the device may be relatively simple. In particular, it can be applied to a large area substrate such as the face of CRT and can be mass-produced, and its industrial value is very high.

Claims (4)

[Claims] 1. A MgF ₂ film produced by applying a liquid containing MgX ₂ (X = a halogen element excluding fluorine) and a BF ₃ complex salt onto a substrate and then heating the same to produce an MgF ₂ film. Production method. 2. A method for forming a low reflection film comprising a single layer or a multilayer film on a substrate, at least one layer of which is a MgF ₂ film, wherein the MgF ₂ film is MgX ₂ (X = halogen element excluding fluorine). ) And a liquid containing BF ₃ complex salt are applied on a substrate and then heated to form a low reflection film. 3. A transparent conductive film is formed on a substrate, and then a MgX ₂ film (X = halogen element excluding fluorine) and BF are formed thereon.
_3. A low reflection film having isoelectric properties consisting of _two layers is formed by applying a liquid containing ₃ complex salts onto a substrate and heating it to form an MgF ₂ film. Method for manufacturing reflective film. 4. The BF ₃ complex salt is BF ₃ alkyl ether complex salt, BF
_At least one selected from the group consisting of ₃ phenol complex salt, BF ₃ alcohol complex salt, and BF ₃ aqueous solution complex salt, the method for producing a MgF ₂ film according to claim 1, or the low reflection film according to claim 2 or 3. Manufacturing method.