JP2001139343A - Hypochromic high-transparency glass and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide hypochromic high-transparency glass, more particularly soda-lime glass having a hypochromic tone and high transmittance adequate as glass for solar battery panels, glass for buildings, etc., and also provide a method for manufacturing such glass. SOLUTION: This hypochromic high-transparency glass consists of a composition which contains 0.02 to 0.05%, by weight %, total iron oxide (Te-Fe2O3) in terms of Fe2O3, as a coloring component, does not substantially contain cerium oxide, Se, CeO, Cr2O3, NiO, V2O5 and MoO3 and is <=40 in the ratio of Feo in terms of Fe2O3 to T-Fe2O3 in the glass essentially consisting of a silica-component. The solar radiation transmittance at a thickness of 3.2 mm of the glass is >=87.5% and the visible light transmittance measured by using a C light source is >=90%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a soda-lime glass having a light color and a high transmittance which is suitable as a glass for a solar cell panel or a glass for an architectural glass, and a glass having such a low cost. Related to the method of manufacturing.

[0002]

2. Description of the Related Art In recent years, there has been a tendency to use lightly colored glass, particularly so-called white plate glass, which is hardly colored, for exteriors of buildings. In addition, solar power generation has been renewed attention as a countermeasure for reducing carbon dioxide gas or fossil fuel depletion, and among them, a cover glass for a solar cell panel used for increasing power generation efficiency is required. Further, as the substrate glass, a glass having a high light transmittance in a wavelength region having a high energy conversion sensitivity in sunlight is required.

[0003] As such a target glass, a glass having a low color and a high transmittance, which is obtained by using a raw material having a high purity and making the iron content extremely smaller than that of ordinary soda-lime glass, is used. Have been.

[0004] For example, the edge-colored transparent glass disclosed in Japanese Patent Publication No. 7-29810 contains less than 0.02% by weight of total iron oxide as a coloring agent expressed as Fe ₂ O _3. A soda-lime glass with a ratio of iron (FeO) in ferrous state to total iron oxide of at least 0.4, whereby a light transmission of at least 87% at a thickness of 5.66 mm (illumination C) It is a glass with little coloring and high transmittance.

[0005] The glass also has a low SO ₃ content to obtain the properties set forth above, and manufacturing features that the melting operation comprises separate liquefaction and fining steps;
It is characterized by the use of limestone and dolomite-free batch materials to reduce the iron content in the glass.

Further, in the edge-colored transparent glass disclosed in Japanese Patent Publication No. 8-715, glass containing the same level of iron oxide is added to a glass having an edge color that matches the wood tone.
Trace amounts of Se and CoO are added so as to obtain a glass having a main transmission wavelength of nm.

Alternatively, as a means for obtaining a glass having a pale color tone and a high transmittance in a glass containing a normal level of iron oxide, an oxidizing agent such as cerium oxide is added to the main component which causes coloring and a decrease in transmittance. Fe
Methods for reducing O are known.

For example, the transparent glass disclosed in Japanese Patent Application Laid-Open No. Hei 5-221683, in which the transmittance of radiated light is adjusted, is a conventional transparent glass containing 0.06 to 0.12% by weight of iron in terms of Fe ₂ O _3. A soda-lime glass sheet containing 0.1 to 0.5% of CeO ₂ as an oxidizing agent, and the ratio of Fe ²⁺ / Fe ^{3+ in} the glass is set to 38 in the case of ordinary soda-lime glass sheet. % To 3 to 10%, and a high transmittance is obtained in a wavelength region around 600 nm or more.

On the other hand, there has been proposed a method of reducing the coloring of a soda-lime glass containing a usual amount of iron oxide as an impurity by changing the mother composition of the glass.

For example, according to the transparent glass composition for producing a window glass disclosed in JP-A-8-40742, the total amount of iron oxide in terms of ferric oxide is 0.0%.
In a soda-lime-silica glass of 2 to 0.2% by weight, its mother composition is expressed in terms of% by weight and 69 to 75% of Si
O ₂ , 0-3% Al ₂ O ₃ , 0-5% B ₂ O ₃ , 2-1
0% CaO, less than 2% MgO, 9 to 17 percent of Na ₂
O, 0 to 8% of K ₂ O, optionally fluorine, zinc oxide, zirconium oxide, and include barium oxide of less than 4 wt%, the total of the oxides of alkaline earth metals by 10 wt% or less By shifting the absorption band of FeO to a longer wavelength, or by linearizing the gradient of the absorption band at the end of the visible range near infrared of the absorption band of FeO, a soda-lime-silica glass having a normal base composition. It is said that it is possible to produce a window glass with less coloring and good infrared absorption.

[0011]

Problems to be Solved by the Invention
In the edge-colored transparent glass disclosed in Japanese Patent Publication No. 10 or Japanese Patent Publication No. 8-715, the total iron oxide expressed as Fe ₂ O ₃ contained as a coloring agent is expressed as a weight percentage from 0.02%. To keep it low, it is not possible to use limestone or dolomite containing relatively large amounts of iron oxide as impurities. This necessitates the use of special raw materials such as calcium carbonate minerals and aluminum hydrates, which have a low iron oxide content, and the resulting glass is expensive.

Further, in the edge-colored transparent glass disclosed in Japanese Patent Publication No. 29810/1995, in order to obtain a desired pure and bright blue color (azure), ferrous iron (FeO) with respect to total iron oxide is used. ) Must be at least 0.4.

To this end, it is desirable to have a special manufacturing method involving separate liquefaction and fining steps as a melting operation and to keep the SO ₃ content low, so that the resulting glass is more expensive. .

In the transparent glass disclosed in Japanese Patent Application Laid-Open No. Hei 5-221683, in which the transmittance of radiated light is adjusted, iron oxide contained at the same level as ordinary soda-lime glass sheet is used.
It is oxidized by adding a required amount of an oxidizing agent, for example, cerium oxide, so that the iron oxide contained therein has a lower Fe ²⁺ / Fe ³⁺ ratio than that of a normal soda-lime glass sheet.

According to this method, although the absorption having a peak around 1000 nm can be reduced by reducing the absorption of FeO, the absorption of Fe ₂ O ₃ near 400 nm is increased. In addition, the color tone of the glass becomes yellowish, which is not desirable in some applications.

Further, since iron oxide is contained in the same degree as ordinary soda-lime glass sheet, a relatively large amount of oxidizing agent is required to lower the ratio of Fe ²⁺ / Fe ³⁺ , and therefore The costs are high.

Increasing the absorption around 400 nm in this way reduces the conversion efficiency of a solar cell made of amorphous silicon having the highest energy conversion sensitivity around 500 to 600 nm. Therefore, it is not preferable.

In a transparent glass composition for manufacturing window glass disclosed in Japanese Patent Application Laid-Open No. 8-40742, a soda-lime glass containing a normal amount of iron oxide can be prepared by changing the mother composition of the glass. Increases transmittance.

However, the effect of the method disclosed in this patent is such that the absorption of FeO is shifted to the longer wavelength side, and a glass for building materials where a light color tone is desired or a glass for a solar cell where a high transmittance is required. Is not enough.

The composition disclosed in the patent is M
Since the amounts of gO and MgO + CaO are small, and the disadvantages caused by melting are compensated for by making the amount of Na ₂ O larger than usual, the weather resistance is poor, burning tends to occur, and the cost is high. The composition is unfavorable for mass production.

The effect disclosed in the patent is F, B
Addition of components such as aO can be strengthened. However, the addition of these components is not preferable because it increases the cost, shortens the kiln life due to volatilization of F, and discharges harmful substances into the atmosphere.

The present invention has been made in view of the above-mentioned problems of the prior art, and has a light color tone and high transmittance suitable for light-colored and highly-transmissive glass, particularly glass for solar cell panels or architectural glass. It is aimed at providing glasses and a method for producing them at low cost.

[0023]

That is, the present invention relates to a glass containing silica as a main component, as a coloring component.
In% by weight, containing total iron oxide in terms of 0.02 to 0.05% by weight of Fe ₂ O _{3 (hereinafter, T-Fe 2 O 3)} , cerium oxide, Se, CoO, Cr ₂ O ₃ , NiO, V ₂ O ₅
And does not substantially contain MoO _3, and ratio _{Fe 2 O 3 T-Fe 2} O 3 of FeO in terms of (hereinafter, Fe
O ratio) is less than 40%, and at a thickness of 3.2 mm, light transmittance is 87.5% or more, and visible light transmittance measured with a C light source is 90% or more. It is glass.

Here, the light-colored high-transmission glass of the present invention desirably has a dominant wavelength larger than 495 nm and smaller than 575 nm, and an excitation purity of 0.4% or less.

The desirable range of the present invention is that F
At an eO ratio of 15% or more and a thickness of 3.2 mm, it is preferable that the dominant wavelength measured using a C light source is smaller than 565 nm and the stimulus purity is 0.3% or less. % FeO and a composition having an FeO ratio of 20% or more.
At a thickness of m, the dominant wavelength measured using a C light source is 5
Desirably, it is smaller than 60 nm.

The above-mentioned desirable range is that the above-mentioned T is appropriately low.
The -fe ₂ O ₃ and not extremely low the FeO ratio is suitable as architectural glass with the desired light color. It is also particularly suitable as a glass for a solar cell made of amorphous silicon having the highest energy conversion sensitivity in the vicinity of 500 to 600 nm.

In this desirable range, when used for a solar cell, not only the transmittance in a wavelength region having high sensitivity is high, but also a suitable amount of FeO is contained.
It also has another favorable effect of appropriately absorbing solar radiation which causes a rise in the temperature of amorphous silicon, which adversely affects the conversion efficiency.

The above-mentioned desirable colorant component and the light-colored high-transmission glass having optical properties have a base glass composition of 65 to 80% SiO ₂ , 0 to 5% A in weight%.
l ₂ O ₃ , more than 2% MgO, 5-15% CaO, 1
0-18% of Na ₂ O, 0 to 5% of the K ₂ O, 7 to 15 percent of MgO + CaO (not inclusive of 7%), 10-20
% Of _{Na 2 O + K 2 O,} 0.05~0.3% of SO _3, and desirably made of 0-5% B ₂ O _3, 10%
It is desirable to contain more MgO + CaO, more than 0.1% SO ₃ . In addition, it is desirable that fluorine, barium oxide, and strontium oxide are not substantially contained.

Further, the light-colored high-transmission glass according to the present invention comprises:
It is desirable that the coloring component is not substantially contained other than iron oxide.

The above-mentioned light-colored high-transmission glass according to the present invention comprises:
Substrate glass for solar cell panel, cover glass for solar cell panel, material for solar water heater, solar heat transmission window glass material, high transmission non-colored mirror, high transmission non-colored window glass, display case protective case glass, front panel, etc. When used as a substrate glass or the like, the effect can be maximized.

In the production of the light-colored and highly transparent glass according to the present invention, dolomite, limestone and alumina-containing silica sand are usually used as raw materials in order to reduce the cost increase of the glass as much as possible. This is desirably made possible by controlling the iron oxide content within the above-mentioned range.

As for the melting method, the liquefaction stage and the fining stage used in a usual soda-lime glass melting furnace are carried out in a single kiln in order to reduce the cost increase of the glass as much as possible. It is desirable to melt in an upper heating tank type melting furnace.

The reason for limiting the composition of the light-colored high-transmission glass of the present invention will be described below. However, the following compositions are expressed in weight%.

Iron oxide is composed of Fe ₂ O ₃ and FeO in the glass.
Exists in the state of. Fe ₂ O ₃ is a component that enhances the ultraviolet ray absorbing ability, and FeO is a component that enhances the heat ray absorbing ability.

In order to obtain a desired light color tone and high transmittance, T-Fe ₂ O ₃ is in the range of 0.02 to 0.05,
Cerium oxide, Se, CoO, Cr ₂ O ₃ , NiO, V ₂
O ₅ and MoO ₃ are not substantially contained and the FeO ratio is 40
%. When T-Fe ₂ O ₃ is less than 0.02%, it is necessary to use a high-purity raw material having a small amount of iron as a raw material, which significantly increases the cost. If the T-Fe ₂ O ₃ , FeO, and FeO ratios are equal to or more than the upper limits of the respective ranges, the visible light transmittance becomes too low, and the blue color tone is enhanced by FeO.

In the case of a glass for a solar cell using amorphous silicon, which desirably has a high transmittance in the vicinity of 500 to 600 nm and an appropriate solar absorption, the above-mentioned amount of T-Fe ₂ O ₃ In the range, FeO is 0.00
It is desirable that the FeO ratio is more than 4% and the FeO ratio is 15% or more. However, if the FeO, FeO ratio is too large, the color tone of the glass becomes strong, so that the FeO ratio is less than 0.012% and the FeO ratio is 20%. It is more desirable to be within the above range.

SiO ₂ is a main component forming the skeleton of glass. If the SiO ₂ content is less than 65%, the durability of the glass decreases, and if it exceeds 80%, melting of the glass becomes difficult.

Al ₂ O ₃ is a component for improving the durability of the glass, but if it exceeds 5%, it becomes difficult to melt the glass. Preferably, it is in the range of 0.1 to 2.5%.

MgO and CaO are used to improve the durability of glass and to adjust the devitrification temperature and viscosity during molding. When the content of MgO is 2% or less, the devitrification temperature increases. If the content of CaO is less than 5%, the solubility deteriorates, and if it exceeds 15%, the devitrification temperature increases. Desirably, CaO is less than 13%. If the total of MgO and CaO is 7% or less, the durability of the glass decreases, and if it exceeds 17%, the devitrification temperature increases. The total of MgO and CaO is preferably 15% or less. When the total amount of MgO and CaO is small, it is necessary to use a large amount of Na ₂ O in order to compensate for the deterioration in solubility and the increase in the viscosity of the glass melt, resulting in an increase in cost and a decrease in chemical durability of the glass. Therefore, the total of MgO and CaO is 10
% Is more desirable.

Na ₂ O and K ₂ O are used as glass melting accelerators. Na ₂ O is poor total dissolution accelerating effect is less than 10% of the or Na ₂ O and K ₂ O is less than 10%, or Na ₂ O exceeds 18% or Na ₂ O and K _2,
If the total amount of O exceeds 20%, the durability of the glass decreases. Since the raw material of K ₂ O is more expensive than Na ₂ O, 5
% Is not preferred.

SO ₃ is a component that promotes fining of glass. If it is less than 0.05%, the refining effect becomes insufficient with a usual melting method, and the desirable range is 0.1% or more. On the other hand, if it exceeds 0.3%, SO ₂ generated by its decomposition will remain in the glass as bubbles or bubbles will be easily generated by reboil.

B ₂ O ₃ is a component used for improving the durability of glass or as a melting aid. If B ₂ O ₃ exceeds 5%, inconvenience during molding due to volatilization of B ₂ O _{3 or} the like occurs, so the upper limit is 5%.

Although TiO ₂ is not an essential component, it can be added in an appropriate amount for the purpose of enhancing the ultraviolet absorbing ability as long as the optical properties aimed at by the present invention are not impaired.
If the amount is too large, the glass tends to take on a yellow tint,
In addition, since the transmittance around 500 to 600 nm decreases,
Its content is desirably kept low within a range of less than 0.2%.

Although the effects of the present invention are not impaired even when fluorine, barium oxide, and strontium oxide are contained, these components have undesirable effects such as an increase in cost, a kiln life, and emission of harmful substances to the atmosphere. Component that exerts
It is desirable not to make it contain substantially.

As a reducing agent, SnO ₂ may be added in a range of 1% or less. Further, the addition of a coloring agent enhances the color tone and lowers the visible light transmittance, so that cerium oxide, Se, CoO, Cr ₂ O ₃ , NiO, V ₂ O ₅ , M
It is desirable not to substantially add oO ₃ or the like.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to specific examples.

(Examples 1 to 9) Raw materials having the composition shown in Table 1 expressed in terms of% by weight in terms of oxide and converted to oxides, were prepared by using low-alumina-containing silica sand, limestone, dolomite, soda ash, boa glass and carbon dioxide. The mixture was prepared using a system reducing agent, and this raw material was heated and melted at 1450 ° C. in an electric furnace. After melting for 4 hours, the glass base was poured out onto a stainless steel plate and gradually cooled to room temperature to obtain a glass having a thickness of about 10 mm. All the concentrations in the table are expressed in weight%.

(Examples 10 to 13) Raw materials having the composition shown in Table 1 expressed in terms of% by weight in terms of oxide and converted to oxides were prepared by using low-iron-alumina-containing silica sand, limestone, dolomite, soda ash, boa glass and carbon dioxide. It was prepared using a system reducing agent. This raw material was melted using a usual soda-lime glass melting furnace (upper heating tank type melting furnace) and made into a plate by a float method to obtain glasses having various thicknesses. All the concentrations in the table are expressed in weight%.

Next, these glasses were polished to a thickness of 3.2 mm, and the optical characteristics were measured using a C light source, such as visible light transmittance, main wavelength, stimulus purity, solar transmittance, and ISO 9050. The specified UV transmittance was measured. Table 1 shows the optical characteristic values of the obtained samples.

[0050]

Table 1 Table 1 Example 1 Example 2 Example 3 Example 3------------------------------------------------------------------------------------------------ 4 Example 5 SiO ₂ 71.7 72.2 71.7 71.2 72.2 Al ₂ O ₃ ----------------------------------------------------------------- 1.7 1.7 1.7 1.8 1.7 MgO 4.2 4.2 4.4 4.2 4.2 CaO 8.5 8.5 8.8 8.5 8.5 Na ₂ O 13.0 12.5 12.5 13.1 12.5 K ₂ O 0.7 0.7 0.7 1.0 0.7 SO ₃ 0.12 0.20 0.15 0.18 0.20 T-Fe ₂ O ₃ 0.025 0.025 0.036 0.036 0.045 TiO ₂ 0.02 0.02 0.04 0.04 0.02 Cerium oxide 0 0 0 0 0 Total 100.0 100.0 100.0 100.0 100.0 FeO 0.008 0.005 0.010 0.008 0.009 FeO ratio 36 22 31 25 22 −−−−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−− Visible light transmittance (%) 91.2 91.5 91.3 91.3 91.3 Solar transmittance (%) 90.0 90.7 89.5 89.9 89.5 Ultraviolet transmittance (%) 79.4 79.7 77.9 76.9 75.0 Dominant wavelength (nm) 529 54 7 499 513 525 Stimulation purity (%) 0.08 0.10 0.14 0.08 0.15 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Example 6 Example 7 Example 8 Example 9 Example 9 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− SiO ₂ 70.4 69.8 69.8 68.0 Al ₂ O ₃ 1.9 2.9 4.9 2.5 MgO 2.1 3.9 2.1 5.9 CaO 11.2 7.8 8.9 8.1 Na ₂ O 12.9 14.6 13.2 14.4 K ₂ O 1.1 0.7 0.9 0.9 SO ₃ 0.22 0.28 0.22 0.27 T-Fe ₂ O ₃ 0.026 0.026 0.022 0.021 TiO ₂ 0.03 0.03 0.04 0.03 Cerium oxide 0 0 0 0 Manganese oxide 0 0 0 0 Total 100.0 100.0 100.0 100.0 FeO 0.008 0.006 0.005 0.004 FeO ratio 34 26 25 21 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− −−−− Visible light transmittance (%) 91.2 91.0 91.5 91.7 Ratio (%) 90.1 90.3 90.8 90.9 UV transmittance (%) 79.1 79.3 79.6 79.7 Dominant wavelength (nm) 530 533 520 551 Stimulation purity (%) 0.11 0.12 0.09 0.07 −−−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− −−−−−− Example 10 Example 11 Example 12 Example 13 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− −−− SiO ₂ 71.7 71.8 71.6 71.8 Al ₂ O ₃ 1.8 1.8 1.8 1.8 MgO 4.1 4.1 4.1 4.1 CaO 7.8 7.8 7.6 7.8 Na ₂ O 13.1 13.0 13.2 12.9 K ₂ O 1.34 1.31 1.34 1.37 SO ₃ 0.19 0.17 0.21 0.22 T-Fe ₂ O ₃ 0.045 0.033 0.027 0.022 TiO ₂ 0.02 0.02 0.02 0.02 Cerium oxide 0 0 0 0 Manganese oxide 0 0 0 0 Total 100.0 100.0 100.0 100.0 FeO 0.014 0.008 0.006 0.005 FeO ratio 35 28 26 23 −−−−−−−−−− −−−−−−−−−−−−−−−−− −−−−−−−−−−−− Visible light transmittance (%) 91.1 91.1 91.3 91.7 Solar transmittance (%) 89.2 89.5 89.9 90.2 Ultraviolet transmittance (%) 75.7 78.2 79.6 79.9 Principal wavelength (nm) 535 553 555 552 Stimulation purity (%) 0.23 0.22 0.22 0.19 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Examples 1 to 13 have compositions within the scope of claim 1. As is clear from Table 1, the visible light transmittance measured with a C light source at a thickness of 3.2 mm is 90% or more, It is a glass having optical characteristics of a solar transmittance of 87.5% or more. The first to thirteenth embodiments are all described in claim 2.
A preferred basic glass composition having a preferred color tone as described in claim 5 and yet as defined in claim 5.

Examples 1 to 13 are compositions in the range of claim 3 which is a more preferable range. The dominant wavelength at a thickness of 3.2 mm is smaller than 565 nm, and the excitation purity is 0.2.
It is a glass having a preferred color tone of 3% or less.

Examples 1 to 9 and 11 to 13 are compositions within the scope of claim 4 which is a more preferable range.
The dominant wavelength at a thickness of 2 mm is smaller than 560 nm,
It is a glass having a more preferable color tone.

Examples 1 to 13 all have compositions within the scope of claim 6 and are also glasses that do not substantially contain fluorine, barium oxide and strontium oxide according to claim 7. Furthermore, these Examples 1 to 13 are glasses which are substantially free of coloring components other than iron oxide and fall within the scope of Claim 8.

Further, in all of Examples 1 to 13, the substrate glass for a solar cell panel, the cover glass for a solar cell panel, the material for a solar water heater, the material for a solar heat transmitting window glass, and the highly transparent uncolored mirror according to the ninth aspect. It is a glass suitable for flat display substrate glass such as high-transparency non-colored window glass, display case protective case glass, and full panel.

(Comparative Examples 1 to 4) Table 2 shows the composition and optical characteristics of Comparative Examples for the present invention. The composition is% by weight.

[0057]

[Table 2] --------------------------------------------------------------------- Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 ------ −−−−−−−−−−−−−−−−−−−−−−−−− SiO ₂ 72.4 73.07 73.50 70.80 Al ₂ O ₃ 1.42 1.80 0.90 1.90 MgO 4.1 0.08 − 3.70 CaO 8.0 10.11 9.00 8.90 SrO − 0.21 − − Na ₂ O 13.1 14.63 15.80 13.50 K ₂ O 0.72 0.01 0.29 0.60 SO ₃ 0.23 0.015 0.30 0.25 T-Fe ₂ O ₃ 0.10 0.010 0.1 0.09 TiO ₂ 0.03 − 0.04 − Cerium oxide − − − −0.20 ZrO ₂ − 0.028 − − Total 100.08 99.935 99.93 99.94 FeO 0.027 0.028 FeO ratio 30 60 31 Plate thickness (mm) 3.20 5.66 3.85 −−−−−−−−−−−−−−−−−−−−−−−−−−−−− − Visible light transmittance (%) 90.1 90.8 89.9 * − Solar transmittance (%) 85.0 88.5 − − UV transmittance (%) 60.8 − − − Dominant wavelength (nm) 502 490.5 541 − Stimulation purity (%) 0.34 0.27 0.30 − − −−−−−−−−−−−−−−−−−−−−−−−−−−−−−− *: Light source is A light source

Comparative Example 1 is a typical soda-lime glass. Comparative Example 2 is described in JP-A-7-298 cited in the text.
The examples in JP-A-10, Comparative Example 3 are the examples in JP-A-8-40742 cited in the text, and Comparative Example 4 are the examples in JP-A-5-221683 cited in the text. There is an example.

In Comparative Example 1, the solar transmittance and the visible light transmittance were lower than those of the glass of the present invention. Comparative Example 2 has the same properties as the glass of the present invention, but the iron oxide content is as low as 0.010%, and a special high-purity raw material is required to reduce the iron oxide content in this way. Cost increases. In Comparative Example 3, the color tone estimated from the visible light transmittance and the stimulus purity is not so different from that of the normal soda-lime glass. In Comparative Example 4, although the optical properties of the glass were not specifically described, when the transmittance at 400 nm was read from the described spectral transmittance curve, the ordinary soda-lime-based glass, which is also described for comparison, was obtained. Compared to about 87%, that of the glass of Comparative Example 4 was about 83%.
This indicates that Fe ₂ O ₃ is increased and the glass has a low transmittance in the visible short wavelength region.

[0060]

According to the first aspect of the present invention, the coloring component T-Fe
By limiting the ratio of ₂ O ₃ , FeO, cerium oxide and FeO, a light-colored high-transmission glass having a high solar radiation transmittance and a high visible light transmittance can be obtained.

According to the second aspect, by limiting the dominant wavelength and the excitation purity, a light-colored high-transmission glass having a color tone preferable for architectural glass and suitable as a glass for a solar cell made of amorphous silicon can be obtained.

According to the third aspect, by further limiting the FeO ratio, a glass having more preferable dominant wavelength and excitation purity can be obtained.

According to the fourth aspect of the present invention, by further limiting the ratio of FeO to FeO, it is possible to obtain a solar cell made of amorphous silicon having a light green color tone which is particularly suitable as architectural glass, and which has high power generation efficiency. A suitable light-colored high-transmission glass is obtained.

According to the fifth aspect, by limiting the basic glass composition, a light-colored high-transmission glass having the above-mentioned desirable optical characteristics can be obtained.

In the sixth aspect, MgO + CaO and SO ₃
By limiting the above, high quality glass can be obtained.

According to the seventh aspect, by limiting the content of fluorine, barium oxide and strontium oxide, generation of harmful substances and deterioration of the melting furnace can be prevented, and a low-cost glass can be obtained.

According to the eighth aspect, by limiting the content of coloring components other than iron oxide, a light-colored high-transmission glass having the above-mentioned desirable optical characteristics can be obtained.

Claim 9 discloses an application in which the light-colored high-transmission glass according to the present invention can exhibit its effects to the maximum.

According to the tenth and eleventh aspects, the cost of the glass can be reduced by limiting the raw materials to dolomite, limestone, and silica sand containing alumina, which are the same as those of the soda-lime glass.

According to the twelfth aspect, the cost of the glass is reduced by melting in an upper heating tank type melting furnace in which the liquefaction step and the fining step, which are used in a normal soda-lime glass melting furnace, are performed in one kiln. It is possible to reduce.

As described above, according to the light-colored high-transmission glass of the present invention, it is possible to obtain a glass having little or no coloring and high transmittance at low cost. Also,
The light-colored high-transmission glass of the present invention is useful as architectural glass, and is also useful as a glass requiring high sunlight transmittance, such as solar cell glass.

Claims (12)

[Claims] In a glass containing silica as a main component, 0.02 to 0.02% by weight as a coloring component.
Total iron oxide in terms of 0.05% Fe ₂ O ₃ (hereinafter referred to as T-
Fe ₂ O ₃ ), cerium oxide, Se, CoO, C
r ₂ O _3, NiO, is substantially free of V ₂ O ₅ and MoO _3, and ratio _{Fe 2 O 3 T-Fe 2} O 3 of FeO in terms of (hereinafter, FeO ratio) is less than 40% And a solar transmittance of 8 at a thickness of 3.2 mm.
A light-colored high-transmission glass having a visible light transmittance of at least 7.5% and a visible light transmittance of at least 90% measured using a C light source. 2. The method according to claim 1, wherein the dominant wavelength is greater than 495 nm and 57
The light-colored high-transmission glass according to claim 1, wherein the stimulus purity is less than 5 nm and the stimulus purity is 0.4% or less. 3. The method according to claim 1, wherein the FeO ratio is 15% or more and 3.2 m
At a thickness of m, the dominant wavelength measured using a C light source is 5
The light-colored high-transmission glass according to claim 1 or 2, wherein the stimulus purity is smaller than 65 nm and the excitation purity is 0.3% or less. 4. A composition containing less than 0.012% of FeO and having a FeO ratio of 20% or more in terms of% by weight, and measured with a C light source at a thickness of 3.2 mm. The light-colored high-transmission glass according to any one of claims 1 to 3, wherein a main wavelength is smaller than 560 nm. 5. The base glass composition, expressed in weight%,
65% to 80% of SiO _2, 0 to 5% of the Al ₂ O _{3, 2%} more than MgO, 5 to 15 percent of CaO, 10 to 18% of the N
a ₂ O, 0-5% K ₂ O, 7-15% MgO + CaO
(But not including 7%), 10-20% Na ₂ O +
K ₂ O, 0.05 to 0.3% of the SO _3, and light-colored high-transmittance glass according to any one of claims 1 to 4, characterized in that it consists of 0-5% B ₂ O _3. 6. More than 10% Mg, expressed as% by weight
O + CaO, light-colored high-transmittance glass according to claim 5, characterized in that it contains more SO ₃ than 0.1%. 7. The method according to claim 1, which is substantially free of fluorine, barium oxide and strontium oxide.
7. The light-colored high-transmission glass according to any one of 6. 8. The light-colored high-transmission glass according to claim 1, wherein the glass does not substantially contain a coloring component other than iron oxide. 9. A substrate glass for a solar cell panel, a cover glass for a solar cell panel, a material for a solar water heater, a window glass material for a solar heat transmission, a high transmission non-colored mirror, a high transmission non-colored window glass, a display case protective case glass, The light-colored high-transmission glass according to any one of claims 1 to 8, wherein the glass is used as a flat display substrate glass such as an entire panel. 10. The method for producing a light-colored and highly transparent glass according to claim 1, wherein dolomite and limestone are used as raw materials. 11. The method for producing a light-colored and highly transparent glass according to claim 10, wherein silica-sand containing alumina is used as a raw material. 12. The method according to claim 10, wherein the batch raw material is melted in an upper heating tank type melting furnace.