JP2509291B2 - Glass substrate - Google Patents

Description

The present invention relates to a glass substrate having excellent weather resistance, and particularly to a glass substrate excellent for use as a magneto-optical disk substrate.

[Prior Art] Conventionally, as a glass substrate having an insulating film, a soda-lime glass substrate is coated with SiO 2 by a chemical vapor deposition (CVD) method.
_{The one in which two} films are formed is widely known. (Eg NG
oldsmith and W. Kern, RCA Review, 28 , 153 (1967)) Also, many glass substrates on which a SiO ₂ —P ₂ O ₅ based film is formed by the chemical vapor deposition method have been reported. (Eg W.ke
RCA, RCA Review 31 [4], 715 (1970)) On the other hand, as a glass substrate on which an insulating film is formed by a solution coating method, a soda lime glass substrate on which a SiO ₂ film is formed (for example, S. Sakka, et. al., J. Non-Cryst, Solids, 6
3, 223 (1984)) or, obtained by forming a composite oxide film based on SiO ₂ -P ₂ O ₅ system (for example, JP 62-158136)
Or those with a SiO ₂ -TiO ₂ film formed (for example, Thin Solid
Films, 77 129 (1981)) is known.

Conventionally, as a magneto-optical disk substrate, one in which irregularities are formed by performing an etching process on a glass substrate is known. (For example, J. Braar and KSImmi
nk, SPIE, 420 206 (1983)) Further, it is known that a glass plate is coated with a solution containing a silicon alkoxide and a mold is pressed to form irregularities. (For example, Japanese Patent Laid-Open No. 62-102445) [Problems to be Solved by the Invention] However, when the conventional glass substrate is kept at high temperature and high humidity (for example, 70 ° C. and relative humidity of 90%), sodium carbonate However, there is a problem in that it is deposited and the substrate is deteriorated.

The above problem has been a serious problem for a substrate such as a magneto-optical disk that requires a particularly high degree of reliability.

[Means for solving the problem]

The present invention has been made in order to solve the above-mentioned conventional problems, in a glass substrate having a surface coated with a SiO ₂ —TiO ₂ based oxide fired film obtained by firing an alkyl group-containing metal organic compound. In the fired film, the alkyl group is left in an amount of 0.5 to 5 wt% with respect to the oxide.

As the substrate that can be used in the present invention, any glass substrate such as soda lime glass, borosilicate glass, aluminosilicate glass can be used, but it is essentially the use of an alkali metal-containing glass such as soda lime glass of the present invention. The effect will be greatly reflected and the price will be low, which is preferable.

The metal organic compound used in the present invention may be any compound as long as it causes a polycondensation or a crosslinking reaction to increase the viscosity of the solution.

For example Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Ti (OC ₃ H ₇ ) ₄ , Ti
_{(OC 4 H 9) 4,} Zr (OC 3 H 7) 4, Zr (OC 4 H 9) 4, Al (OC 3 H 7) 3,
M (OR) _n [M is a metal such as Si, Ti, Zr, Ca, Al, Na, Pb, B, Sn, Ge, R is methyl, Al (OC ₄ H ₉ ) ₃ and NaOC ₂ H ₅ are alkyl groups such as ethyl, n represents a compound represented by the integer from 1 to 4] and _{-Cl, -COOH, -COOR, -NH 2} , Examples thereof include metal organic compounds containing a general functional group that undergoes polycondensation or cross-linking reaction.

The baked film of the metal organic compound on the glass substrate is a method of immersing the glass substrate in a solution containing the metal organic compound (hereinafter abbreviated as a solution) and then pulling it up (commonly called dipping method), and a method of dropping the solution and then rotating it. It is prepared by drying and baking a coating film prepared by a commonly used film forming method such as a so-called spin coating method and a spray method.

The present invention provides a SiO ₂ —TiO ₂ -based fired film of the metal organic compound, wherein the alkyl group of the metal organic compound is 0.5 to the oxide.
It is assumed that the residual amount of the alkyl group is up to 5 wt%, but if the residual alkyl group in the fired film is more than 5 wt%, the mechanical properties of the fired film are extremely deteriorated. The residual alkyl group is 0.5wt
If it is less than%, the effect of improving the weather resistance of the present invention does not appear.

The present invention, as a baked film of a metal organic compound, SiO ₂ -TiO ₂
Although a SiO ₂ -TiO ₂ -based film is used, the weather resistance is remarkably improved. Among the SiO ₂ -TiO ₂ based amorphous films, SiO ₂ -TiO ₂
It is desirable to use a binary amorphous film because it is easy to manufacture.

The TiO ₂ content in the SiO ₂ —TiO ₂ amorphous film can be set arbitrarily, but is preferably 6 to 70 mol%.
Even if the TiO ₂ content of the film is less than 6 mol% and exceeds 70 mol%, the effect of improving the weather resistance of the glass substrate on which the film is formed is less likely to appear.

Particularly, a substrate having a TiO ₂ content of 6 to 12 mol% is preferable as a substrate for optical use. TiO _{2 of the} film body
When the content is less than 6 mol% or more than 12 mol%, light reflection tends to increase at the interface between the film body and the glass substrate.

In particular, when an organic polymer (polyethylene glycol, etc.) as a thickener is included in the coating film preparation solution, the fired film formed becomes a film with high porosity and the refractive index decreases. Therefore, the TiO ₂ content for the optical applications is
It is preferably 10 to 25 mol%. Even if the content is less than 10 mol% and more than 25 mol%, the reflection of light at the interface between the film body and the glass substrate is likely to increase.

In particular, in the method for producing a magneto-optical disk substrate by transferring a groove shape such as a press die to the coating film, it is preferable to add a thickener to the coating solution in terms of workability, In such a case, the TiO ₂ content is preferably 10 to 25 mol% as described above. (When it is performed without adding a thickener to the coating solution, it is preferably 6 to 12 mol%.) The metal organic compound in which the alkyl group of the starting metal organic compound remains 0.5 to 5 wt% with respect to the oxide. The baked film of is obtained, for example, by heat-treating the coating film of the metal organic compound at a temperature of 90 to 400 ° C.

When heat treatment is performed at a temperature of less than 90 ° C, residual alkyl groups are 5 wt%
% Or less, and a large amount of water remains in the film, and problems due to water are likely to occur. Further, as described above, the film tends to have low mechanical strength. When the heat treatment is performed at a temperature higher than 400 ° C, the residual alkyl groups are unlikely to reach 0.5 wt% or more, and during the heat treatment, alkali metal ions in the substrate glass enter the baked film of the metal-organic compound by diffusion, and 90 to 400
It tends to show a lower effect than the effect of improving the weather resistance of the coating film baked at ℃. Further, the firing temperature is preferably 90 to 200 ° C. because particularly good weather resistance can be obtained.

The average film thickness of the baked film of a metal organic compound such as the SiO ₂ —TiO ₂ amorphous film is preferably 0.02 to 2.0 μm. When the film thickness of the film body is less than 0.02 μm, the degree of improvement in weather resistance of the glass substrate by providing the film body is low. If the film thickness of the film exceeds 2.0 μm, the problem of delamination easily occurs.

Especially when used as a magneto-optical disk substrate,
The average film thickness of the SiO ₂ —TiO ₂ based amorphous film is preferably 0.15 to 2.0 μm.

By providing the film on both sides of the glass plate, both sides of the glass plate can be protected. However, it can be carried out in any form such as being provided on one surface of the glass plate if necessary.

When used as a magneto-optical disk substrate, an etching method or a sol-gel stamp method is applied to a glass substrate (Japanese Patent Laid-Open No. 62-
102445) or the like to form a groove, and then a baked film of a metal organic compound may be formed. However, a method of providing a film body having unevenness on the surface of a smooth glass substrate is preferable because of high productivity. The unevenness may be provided on at least one surface.

The residual alkyl group in the metal organic compound can be measured, for example, by infrared spectrophotometry, thermogravimetric analysis, or the like.

The amount of the alkyl group of the metal organic compound contained in the solution used for coating changes when the degree of polymerization of the metal organic compound changes, but the residual amount of the alkyl group of the metal organic compound referred to in the present invention means the metal organic compound. Is evaluated on the basis of the weight when it is completely oxidized. (For example, if the raw material Si (OC ₂ H ₅ ) is not hydrolyzed and exists as a monomer, unreacted alkyl groups are contained in 247 wt% based on the weight of the oxide SiO ₂ . In addition, when three alkyl groups are present in the monomer after being hydrolyzed, that is, in the form of Si (OC ₂ H ₅ ) (OH) ₃ , unreacted alkyl groups are present. The amount of unreacted alkyl groups decreases as the degree of polymerization increases and the degree of hydrolysis progresses, that is, in an inorganic polymer consisting of 10 silicon (Si) atoms. 1 unreacted ethoxy group
In the case where there is one, 6 wt% alkyl group is contained. ) [Operation] According to the present invention, the fired film of the SiO ₂ —TiO ₂ -based metal organic compound acts as a diffusion preventing layer for sodium ions from the glass substrate side, and protects the glass substrate to improve weather resistance. Plays the role of a membrane.

When a material in which the alkyl group of the metal organic compound remains in an amount of 0.5 to 5 wt% with respect to the oxide is used as the fired film of the metal organic compound, the alkyl group in the fired film performs an action such as capturing an alkali metal. It is thought that excellent weather resistance can be realized.

Further, in such a fired film having a residual alkyl group of 0.5 to 5 wt%, the inorganic skeleton has already been sufficiently developed, and the mechanical strength is not significantly impaired.

〔Example〕

Example 1 As a starting material, silicon tetraethoxide (Si (OC
₂ H ₅ ) ₄ ) and titanium tetra n-butoxide (Ti
_{(O-nC 4 H 9)} 4) using, the solvent ethanol, the hydrolysis catalyst using hydrogen chloride, respectively. The amount of water added was 4 times the molar ratio of silicon tetraethoxide. Dilute hydrochloric acid (1 wt%) was added to an ethanol solution of silicon tetraethoxide, and the mixture was stirred at room temperature for 30 minutes. Then, an ethanol solution of titanium tetra-n-butoxide was gradually added, and the mixture was reacted at room temperature for another 30 minutes. The molar ratio of silicon tetraethoxide and titanium tetra n-butoxide was set to 91: 9.

The solution thus obtained is yellow to colorless and transparent, and the oxide conversion concentration is 8.5 wt%. The solution was diluted with ethanol to twice the volume to obtain a coating solution.

By dipping a soda lime glass substrate in the coating solution and pulling it up at a constant speed (1.6 mm / Sec), 91 SiO ₂ · 9
A TiO ₂ coating film was formed on a glass substrate. The coating film is made of acetyl cellulose having a large number of peaks with a peak height of 0.15 μm, a peak width of 2 μm, and a peak interval of 4 μm (modulus of elasticity 10 ⁴ kg
A mold with a thickness of 50 μm (f / cm ² ) was pressed and joined.

Then, the glass substrate with a coating film bonded to the mold was dried at room temperature for 15 minutes, then primary baking was performed in the atmosphere at 90 ° C. for 30 minutes in a clean oven, and then the mold made of acetylose was released from the mold. . The glass substrate with the coating film after the mold release was finally baked at 400 ° C. for 15 minutes.

By this final baking, the coating film was an amorphous film with an average thickness of 210 nm (refractive index 1.52).

The surface and cross section of the magneto-optical disk substrate produced by the above operation were observed by a scanning electron microscope. As a result, a good groove shape having a groove depth of about 75 nm, a groove width of about 2 μm and a groove interval of about 4 μm was formed.

FIG. 1 shows a schematic cross section of a magneto-optical disk substrate manufactured by the above-mentioned embodiment.

Next, a weather resistance test was conducted on the magneto-optical disk substrate. The weather resistance test was conducted by once dew condensation, and then keeping it in an atmosphere of 70 ° C. and 90% relative humidity for 4 days.

The surface of the magneto-optical disk substrate after the weather resistance test was uniform as in the case before the weather resistance test, and neither surface deterioration nor generation of precipitates was observed.

The same weather resistance test was performed on the magneto-optical disk substrate manufactured by the same manufacturing method as in this example except that the final firing temperature was changed to 90 ° C and 200 ° C.

Whether the final heat treatment at 90 ° C or the final heat treatment at 200 ° C was the same as the final heat treatment at 400 ° C, the surface of these magneto-optical disk substrates after the weather resistance test was uniform and the surface was not deteriorated. No generation of deposits was observed.

When the residual alkyl group in the baked film baked at each of the above 90 ° C, 200 ° C and 400 ° C was measured by thermogravimetric analysis, the alkyl group of the starting metal organic compound (before dehydration condensation) was compared with the oxide. It was found that 4.4, 3.7 and 0.8 wt% remained respectively. The composition of the SiO ₂ —TiO ₂ -based amorphous film is 91SiO ₂ ·
It is not limited to 9TiO _2, TiO ₂ in the present system the 6
A magneto-optical disk substrate having similar weather resistance was obtained in the composition range containing ~ 12 mol%.

Comparative Example-1 The same weather resistance test as in Example-1 was carried out on the glass substrate with the SiO ₂ amorphous film having the surface irregularities instead of the glass substrate with the SiO ₂ —TiO ₂ based amorphous film having the surface irregularities. I went.

In the method for producing the SiO ₂ amorphous film, silicon tetraethoxide was used as a starting material. Hydrogen chloride was used as the solvent for the ethanol hydrolysis catalyst. The amount of water added and the amount of ethanol were 6 and 5 with respect to silicon tetraethoxide in a molar ratio, respectively.

Dilute hydrochloric acid (1 wt%) was added to an ethanol solution of silicon tetraethoxide, and the mixture was stirred at room temperature for 1 hour. The solution thus obtained was colorless and transparent, and the solution was diluted with ethanol to a volume three times as large as a coating solution.

Using the coating solution, the same operation as in Example-1 was performed to prepare a glass substrate with a SiO ₂ amorphous film having irregularities on the surface. After the final baking at 400 ° C. for 15 minutes, the SiO ₂ amorphous film had an average thickness of 200 nm and a refractive index of 1.45.

A schematic cross section of the magneto-optical disk substrate manufactured by the above operation is shown in FIG. The same weather resistance test as in Example-1 was performed on the magneto-optical disk substrate manufactured according to this comparative example.

The diameter of the surface of the magneto-optical disk substrate after the weather resistance test
Precipitated particles of 0.1 μm to 0.2 μm were deposited on the entire surface at a density of 32 per square micrometer. As a result of analysis, the deposited particles were found to be sodium carbonate.
A schematic cross section of the magneto-optical disk substrate after the weather resistance test
Shown in the figure. The same weather resistance test was conducted on the magneto-optical disk substrate manufactured by the same manufacturing method as in this comparative example except that the final firing temperature was changed to 90 ° C and 200 ° C. Both the final heat treatment at 90 ° C and the final heat treatment at 200 ° C are
Precipitated particles having a diameter of 0.1 to 0.2 .mu.m were observed to the same extent on the surfaces of these magneto-optical disk substrates as in the case of the final heat treatment at .degree.

When the residual alkyl groups in the respective baked films at 90 ° C., 200 ° C. and 400 ° C. were measured in the same manner as in Example-1, 4.3, 4.1 and 1.1 wt% of alkyl groups remained on the oxide (SiO ₂ ) respectively. I found out that

Comparative Example-2 A photoresist film was formed on a chemically strengthened soda lime glass substrate by a spin coating method, and a groove shape as a magneto-optical disk substrate was selectively exposed using an exposure device. After the development process, a continuous groove shape having a width of about 1.6 μm and a depth of about 70 nm was formed on the substrate by dry etching. FIG. 4 shows a schematic cross-sectional view of the glass substrate after removing the photoresist.

The same weather resistance test as in Example-1 was performed on the magneto-optical disk substrate manufactured by the above operation. The surface of the magneto-optical disk substrate after the weather resistance test was extremely deteriorated, and a mesh-like precipitate having pores with a diameter of 1 to 5 μm was observed on the entire surfaces of both surfaces.

As a result of analysis, the reticulated precipitate was found to be sodium carbonate. A schematic cross section of the magneto-optical disk substrate after the weather resistance test is shown in FIG.

Example-2 Polyethylene glycol having an average molecular weight of 600 (PEG600) was added to the coating solution prepared in Example-1 in a weight ratio (PEG60) of the final product of 91SiO ₂ .9TiO ₂ composition.
The amount of (0) / (oxide) = 1 was added and uniformly dissolved to obtain a coating solution.

Using the coating solution, the same operation as in Example-1 was performed to prepare a PEG600-added 91SiO ₂ .9TiO ₂ amorphous film-coated glass substrate having irregularities on the surface. After the final baking at 400 ° C. for 15 minutes, the coating film was an amorphous film having an average thickness of 400 nm. The refractive index was decreased to 1.46 after the final baking by adding PEG; the porosity of the thin film was increased.

When the surface and cross section of the magneto-optical disk substrate manufactured by the above operation were observed with a scanning electron microscope, a good groove shape having a groove depth of 69 nm, a groove width of about 2 μm and a groove interval of about 4 μm was formed.

The same weather resistance test as in Example-1 was performed on the magneto-optical disk substrate manufactured in this example.

The surface of the magneto-optical disk substrate after the weather resistance test was uniform as in the case before the weather resistance test, and neither surface deterioration nor generation of precipitates was observed.

The same weather resistance test was performed on the magneto-optical disk substrate manufactured by the same manufacturing method as in this example except that the final firing temperature was changed to 90 ° C and 200 ° C.

Both the final heat treatment at 90 ° C and the final heat treatment at 200 ° C were similar to those of the previous final heat treatment at 400 ° C, and the surface of those magneto-optical disk substrates after the weather resistance test was uniform and the surface was not deteriorated. No generation of deposits was observed.

The amount of unreacted alkyl groups remaining in each of the baked films at 400 ° C. was 1.2 wt% (vs 91 SiO ₂ : 9TiO ₂ oxide).

The composition of the PEG600-added SiO ₂ -TiO ₂ -based amorphous film is 91
Not limited to SiO ₂ · 9TiO ₂ , but TiO _{2 in} this system
A magneto-optical disk substrate with similar weather resistance was obtained in the composition range containing 10 to 25 mol% of. Especially TiO ₂
A film body of this composition containing PEG 600, containing 17 mole percent, has a refractive index of 1.51 after heat treatment at 400 ° C. for 15 minutes,
The reflectance of light at the interface between the film body and the glass substrate was small and excellent. (The residual alkyl groups in the above-mentioned 83SiO ₂ · 17TiO ₂ 400 ° C. calcined film was 0.7 wt% with respect to the oxide.) Example-3 A soda lime glass plate was added to the coating solution prepared in Example-1. It was dipped and pulled up at a constant speed (1.8 mm / Sec) to prepare a coating film.

Glass substrate with the coating film at 90 ° C for 30 minutes at 200 ° C, 1
Heat treatment was performed at 400 ° C. for 15 minutes for 5 minutes.

The thickness of the film body heat-treated at 90 ℃ is about 280 nm, the one heat-treated at 200 ℃ is 260 nm and the one heat-treated at 400 ℃ is 22
It was 0 nm respectively.

All the film bodies were amorphous. A weather resistance test was performed on each lath substrate with different heat treatment temperatures.

For the weather resistance test, first test each glass substrate at 70 ° C and 90% relative humidity.
It was carried out by holding in the atmosphere of 4 days.

The surface of each glass substrate after this weather resistance test was as uniform as before the weather resistance test, and neither surface deterioration nor generation of precipitates was observed.

Further, a dew condensation test was carried out in which each glass substrate was once condensed and then kept in an atmosphere of 70 ° C. and 90% relative humidity for 4 days.

After the dew condensation test, the surface of each glass substrate was found to have deposited particles of only about 0.1 μm in the one heat-treated at 400 ° C, but no deterioration or precipitation was observed in the one heat-treated at 90 ° C and 200 ° C. No matter was observed, and it was found that the glass substrate manufactured by this method as a whole has extremely excellent weather resistance.

In particular, the glass substrate formed with the film has a weather resistance of 90.
What was heat-treated at ℃ ~ 200 ℃ was very excellent.

Example 4 Silicon tetraethoxide was added to an ethanol solution of titanium tetra-n-butoxide, stirred at room temperature for 20 minutes, concentrated hydrochloric acid (36 wt%) was added, and the mixture was reacted at room temperature for 20 minutes. Next, the molar ratio to all metal alkoxide is 4
Insufficient water was added to double the amount, and stirring was continued at room temperature for 20 minutes.

The molar ratio of titanium tetra-n-butoxide and silicon tetraethoxide was set to 70:30.

The solution thus obtained was diluted with ethanol to a 4-fold volume to give a coating solution.

Using the solution, the same operation as in Example-3 was performed to obtain 30Si.
An O ₂ · 70TiO ₂ coating film was formed on a soda lime glass substrate.

The glass substrate with the coating film was treated at 90 ° C. as in Example-4.
Heat treatment was performed for 30 minutes, 200 ° C. for 15 minutes, and 400 ° C. for 15 minutes.

The thickness of the film body heat-treated at 90 ° C is about 240 nm, the thickness of heat-treated at 200 ° C is 210 nm, and the thickness of heat-treated at 400 ° C is 18 nm.
It was 0 nm respectively.

All the film bodies were amorphous. The residual alkyl groups in the baked film were measured at 90 ℃, 200 ℃ and 400 ℃.
It was 4.2, 3.9 and 0.6 wt (vs. 30 SiO ₂ · 70 TiO ₂ oxide).

The same weather resistance test and dew condensation test as in Example-1 were performed on the glass substrates manufactured in the above Examples.

Consequently 30SiO ₂ · 70TiO ₂ amorphous film with a glass substrate manufactured by this example we described in the previous Example -3 91SiO ₂
・ As with the glass substrate with 9TiO ₂ amorphous film, no surface deterioration or precipitates were observed after the test, indicating that it has excellent weather resistance. Moreover, the one heat-treated at 90 ° C to 200 ° C was particularly excellent in terms of weather resistance.

The composition of the SiO ₂ —TiO ₂ -based amorphous film is 91SiO ₂ · 9TiO ₂ or 30SiO ₂ · 70T of the above-mentioned Example-4 and Example-5.
It is not limited to iO ₂ , but TiO ₂ of 6 to 7 is used in this system.
A glass substrate having similar weather resistance was obtained in the composition range containing 0 mol%.

Comparative Example-3 A soda lime glass plate having no film body was subjected to the same weather resistance test as in Example-4.

The surface of the glass substrate having no film body after being kept at 70 ° C. and 90% relative humidity for 4 days was extremely deteriorated, and a network-like precipitate having pores with a diameter of 1 to 7 μm or a diameter of 0.2 Precipitated particles of ˜0.4 μm were observed.

As a result of analysis, these precipitates were found to be sodium carbonate.

SiO ₂ -TiO ₂ type SiO ₂ instead of glass substrate with amorphous film
The same weather resistance test as in Example-3 was performed on the glass substrate with an amorphous film.

Using the coating solution prepared in Example 2, the same operation as in Example 3 was performed to form a SiO ₂ coating film on a soda lime glass plate.

The glass substrate with the coating film is heated at 90 ° C for 30 minutes at 200 ° C for 15 minutes.
Each heat treatment was performed at 400 ° C. for 15 minutes.

The thickness of the film heat-treated at 90 ° C is about 280 nm. The thickness of the film heat-treated at 200 ° C is about 23 nm at that of 260 nm and 400 ° C.
It was 0 nm respectively.

 All the film bodies were amorphous.

The weather resistance test similar to that of Example-3 was performed on the glass substrate manufactured according to this comparative example.

The surface of the glass substrate after the condensation test has a diameter of 0.1 to 0.2 μ.
Precipitated particles of m were deposited on the entire surface.

Further, the amount of precipitation of particles increased as the temperature of the heat treatment increased, and particularly in the sample heat-treated at 400 ° C., streak-like precipitates having a width of 2 to 4 μm were observed on the entire surface.

As a result of analysis, these precipitates were found to be sodium carbonate.

Table 1 shows the weather resistance and the residual alkyl groups (relative to the final oxide) in the fired films of the glass substrates and other glass substrates produced in the above Examples and Comparative Examples.

The weather resistance in Table 1 is that all the surfaces of the glass substrates after the weather resistance test were inspected and evaluated by a scanning electron microscope (SEM), and ⊚ indicates that the weather resistance is good. △
>×>××> ×××× indicates deterioration, and ×××× indicates poor weather resistance.

Alkyl group residual firing film-coated glass substrate using a metal organic compound as a starting material, a glass substrate obtained by firing the metal organic compound at a temperature of 500 ° C. or higher as is clear from the above table,
Compared to a glass substrate that does not have a film body, it is extremely excellent in weather resistance.

The glass substrate with a film obtained by low-temperature firing of the metal organic compound of the present invention is not only a substrate for a magneto-optical disk, but also an electroluminescent element, an electrochromic element, a display element such as a liquid crystal element, and an electronic component such as a thin film transistor. It can also be applied as a glass substrate to be formed. Also, by forming this film body on optical parts,
The environment resistance can be improved.

〔The invention's effect〕

As is clear from Examples and Comparative Examples, the glass substrate of the present invention is very excellent in weather resistance as compared with the glass substrate manufactured by the conventional method. Therefore, it can be used as a substrate having higher reliability than the conventional glass substrate.

[Brief description of drawings]

FIG. 1 is a sectional view showing the outline of the magneto-optical disk substrate manufactured in Example-1, FIG. 2 is a sectional view showing the outline of the magneto-optical disk substrate manufactured in Comparative Example-1, and FIG. 3 is a comparative example. FIG. 3 is a cross-sectional view showing an outline of the magneto-optical disk substrate manufactured in -1 after a weather resistance test. FIG. 4 is a sectional view showing the outline of the magneto-optical disk substrate manufactured in Comparative Example-2, and FIG. 5 is a sectional view showing the outline of the magneto-optical disk substrate manufactured in Comparative Example-2 after the weather resistance test. Is.

Claims (3)

(57) [Claims] 1. A glass substrate having a surface coated with a SiO ₂ —TiO ₂ -based oxide calcined film obtained by calcining an alkyl group-containing metal organic compound, wherein the alkyl group in the calcined film is 0.5 A glass substrate characterized in that it remains up to 5 wt%. 2. The glass substrate according to claim 1, wherein the fired film is a fired film at a temperature of 90 to 400 ° C. 3. The glass substrate according to claim 1, wherein the fired film is a film having unevenness on the surface.