JPH02116804A - Production of mgf2 film and production of low reflection film - Google Patents

Abstract

PURPOSE:To obtain the MgF2 film which is simple and stable and has low reflection characteristics by applying a liquid contg. Mg(BF4)2 and MgX2 on a substrate, then heating the substrate, thereby producing the MgX2. CONSTITUTION:The Mg(BF4)2 film is formed by applying the liquid contg. the Mg(BF4)2 and the MgX2 (X=halogen elements exclusive of fluorine) on the substrate, then heating the substrate. The low reflection film is thereby produced. Namely, the the MgX2 film is considered to be formed on the bases of the reaction Mg(BF4)2+3MgX2 4MgF2+2BX3 in forming the MgX2 film by bringing the Mg(BF4)2 and the MgX2 into reaction. The boron (B) of the Mg(BF4)2 removes X of MgX2 in the form of the gas of BX3. The extremely pure MgX2 is, therefore, formed efficiently if the Mg(BF4)2 and the MgX2 are used at 1:3 molar ratio. The excellent MgX2 and the low reflection film contg. MgF2 film are thereby obtd. efficiently in this way by the simple method.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method of manufacturing a low reflection film.

[Prior Art] Coating methods for low-reflection films have been studied extensively not only in optical equipment, but also in consumer equipment, especially cathode ray tubes (CR'r) for TVs and computer terminals.

Conventional methods include, for example, as described in JP-A-61-118931, in order to provide an anti-glare effect to the surface of a cathode ray tube, a SiO□ layer having fine irregularities is attached to the surface, or the surface is etched with hydrofluoric acid to remove irregularities. Methods such as establishing a However, these methods are called non-glare treatments that diffusely reflect external light, and are essentially not methods of providing a low-reflection layer, so there is a limit to the reduction in reflectance.

In addition, tAgF2, a stable low refractive index substance, has been applied to each lens and glass surface by physical means such as vacuum evaporation, but this method requires high equipment costs or requires a complete CRT sphere. The disadvantage is that it is difficult to accommodate large adherents such as these in a vacuum chamber.

[Problems to be Solved by the Invention] The purpose of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide a new method for producing a MgFz film that is simple, stable, and has excellent low reflection characteristics by a chemical method. By providing.

[Means for Solving the Problems] That is, the present invention provides an MgF2 film characterized in that a liquid containing Mg(BF4)a and MgX2 (X = halogen element excluding fluorine) is applied onto a substrate and then heated. and a method for forming a low reflection film consisting of a single layer or a multilayer film on a substrate, at least one of which is a MgF film, in which the MgF2 film is formed of Mg(BFn)z and Mg
The present invention provides a method for producing a low-reflection film, characterized in that it is formed by applying a liquid containing L (X = halogen element excluding fluorine) onto a substrate and then heating it.

The feature of the present invention is that Mg(BF4)z and Mgxz (hereinafter collectively referred to as starting materials) are reacted to form a MgF2 film.

In the present invention, it is thought that MgF 2 is produced based on the reaction of the following formula.

Mg (BF41 m + 3MgL→4MgF2+
28Xa↑ (1) The above reaction easily proceeds by dispersing or dissolving the starting material in a solvent and further heating.

As the starting material MgL, MgC1z, MgBrz
, MgIt, etc. can be used, but MgClg is particularly preferred because the reaction of the above formula (1) proceeds most easily.

The solvent is not particularly limited, but organic high dielectric constant solvents such as water, water-soluble solvents, alcohol propylene carbonate, and γ-butyrolactone can be used.

The reaction of formula (1) proceeds even in a solid phase, so even if the starting material is not dissolved in the solvent but dispersed as a lump,
Although the process progresses by heating, it is difficult to form uniform pus and it is difficult to obtain sufficient adhesion strength of the membrane to the substrate, so it is preferable to use a solution in which the starting material is dissolved. Also, considering the stability of the starting material in the solvent,
As the solvent, alcohols, particularly methanol, ethanol, propatool, butanol, etc. are preferred.

It is preferable to use Mg(BF4)z and Mgx2 in a molar ratio of 1:3 as the starting materials because the reaction of the above formula (1) proceeds most efficiently.

Further, it is preferable that the starting materials, together with Mg(BF-)2 and MgX2, are contained in an amount of 1 to 30 wt% based on the solvent.

Furthermore, Mg(BF4)z and MgL used in the present invention
In order to improve the adhesion strength and hardness of the film, sodium linear alkylbenzene sulfonate such as Si(OR)4 (R: alkyl group), alkyl ether sulfate, etc. may be added to the liquid containing . In addition, for the purpose of imparting conductivity, metal oxides having conductivity (for example, Sn
O. , Sn-containing IniOs (ITO), etc.), organic metal salts such as acetylacetonates, alkoxides, halides, acetates, nitrates, or chelate compounds of metals (e.g., Sn, In, etc.). , Mg(sp+)z and MgX used in the present invention
2 and In.2 containing Snow or Sn.
It is also possible to precipitate 03 (ITO) etc. at the same time.

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

The method of attaching the film to the substrate is spin code method, dip method,
Various methods can be considered, such as a spray method, a roll coater method, a meniscus coater method, etc., but the spin code method is particularly preferable because it has excellent mass productivity and reproducibility. By this method, it is possible to form a MgF2 film with a thickness of about 100 to 1 μm.

In the present invention, the substrate on which the MgFz film and the low reflection film containing MgFi are formed is not particularly limited, and depending on the purpose, soda lime silicate glass, aluminosilicate glass, borosilicate glass, lithium aluminosilicate glass can be used. , glasses such as quartz glass, single crystals such as corundum, translucent ceramics such as magnesia and sialon, and plastics such as polycarbonate can be used.

The method for manufacturing a MgF2 film of the present invention can also be applied to manufacturing a multilayer low reflection film including a MgFa film. The structure of a multilayer low-reflection film having anti-reflection performance is as follows: The wavelength to be anti-reflected is set to λ, and from the base side, a high refractive index layer and a low refractive index layer are formed with an optical thickness of λ/2-λ/4. A three-layer low-reflection film formed from the substrate side by forming a medium refractive index layer, a high refractive index layer, and a low refractive index layer with an optical thickness of λ/4-n/2-λ/4,
A 4-layer low-reflection film, etc., formed from the substrate with a low refractive index layer, a medium refractive index layer, a high refractive index layer, and a low refractive index layer with an optical thickness of /4-λ/4-e/2-e/4. This is known as a typical example, and in the present invention, MgF, a film (n
It is also possible to manufacture a multilayer low-reflection film using 1.38).

In addition, it is a solution to the problem that has been pointed out in cathode ray tubes (CRTs) and front panels, where the surface is charged due to static electricity generated during CRT operation, causing discharge between the CRT and the human body, and causing lumps to be easily attracted. It is known that one layer of a low-reflection film is made of a transparent and conductive material, but it can also be applied to the production of such a conductive low-reflection film. For example, substrate/SnO□/MgF2, substrate/I
A low reflection film such as TO/MgF2 can also be formed.

[Function] In the present invention, as described above, Mg(BF4)z+ 3MgL = 4MgF2+ 2
BXa↑ ... (It is thought that MgF2 film is generated based on the reaction 11. Mg(BF4)z boron (
Since Bl removes the
If used at a ratio of =3, efficient and extremely pure MgF can be obtained.
A film can be formed.

[Example] Example 1 ll1g(BF4)z and MgC1□ in a molar ratio of 1:3 to methanol-butanol mixed solvent (volume ratio 1:2)
Further, the total amount was added and dissolved in such a manner that the concentration was 5% by weight based on the solvent.

A glass substrate was coated by dipping into this solution, and further coated with a spin coater at a rotation speed of 3000 rpm. This glass substrate was baked in air at 250°C for 30 minutes to obtain a
After forming the human MgFa film, the wavelength 360~700 (
The single-sided reflectance at 100 nm) was measured.

Example 2 A MgFa film (1150 people) was formed in the same manner as in Example 1 except that the firing temperature was 150°C.

Example 3 MgFa)1 (1100 people) was formed in the same manner as in Example 1 except that methanol-butanol (volume ratio 1.1) was used as the solvent.

Example 4 A MgF2 film (1200 people) was formed in the same manner as in Example 1 except that the rotation speed of the spin coater was 300 rpm.

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

Wavelength 520 as measurement results of Examples 1 to 4 and comparative example
Table 1 shows the reflectance in (nm).

Table 1 Example 5 5 for a solvent consisting of methanol and water (volume ratio 1:1)
nC1,, 5bC1s to the solvent at 2°0.2wt each
A glass substrate was dip-coated in a solution in which the amount of 10% of Sn0w was added and dissolved, and further coated with a spin coater at a rotational speed of 300 rpm, and then baked in air at 400° C. for 30 minutes to form a 1100-layer Sn0w film. Next, Example 1
A MgFi film (film thickness: 950 mm) was formed in exactly the same manner as described above, and was made into glass/SnO□/MgFi. wavelength 520
(nm) reflectance was 1.4%.

[Effects of the Invention] According to the present invention, a liquid containing Mg(BF4)z and Mgx2 can be sprayed onto a substrate by a simple method such as spraying or using a spin cord, or immersing the substrate in the liquid.
, excellent λ! It becomes possible to provide a low reflection film including a gF 2 film and a MgFz film.

The present invention has excellent productivity and does not require a vacuum, so the apparatus may be relatively simple.

In particular, it can be sufficiently applied to large-area substrates such as the face of a CRT, and can be mass-produced, so its industrial value is extremely high.

Claims (3)

[Claims] (1) A method for producing an MgF_2 film, which comprises applying a liquid containing Mg(BF_4)_2 and MgX_2 (X = halogen element excluding fluorine) onto a substrate and then heating it to produce an MgF_2 film. (2) In a method of forming a low reflection film consisting of a single layer or a multilayer film on a substrate, at least one of which is an MgF_2 film, the MgF_2 film is replaced with Mg(BF_4)_2
and MgX_2 (X = halogen element excluding fluorine) is applied onto a substrate and then heated. (3) Form a transparent conductive film on the substrate, then apply a liquid containing Mg(BF_4)_2 and MgX_2 (X = halogen element excluding fluorine) thereon, and heat it to form the MgF
3. The method of manufacturing a low-reflection film according to claim 2, wherein a two-layer low-reflection film is formed by forming the _2 film.