KR101126872B1 - Manufacturing Method of Glass Substrate for Flat Panel Glass - Google Patents

Abstract

This invention makes it a subject to provide the manufacturing method of the glass substrate for flat panel glass which can prevent Ag colloid coloration, and the flat substrate glass substrate obtained by the said manufacturing method, maintaining favorable scratch resistance. This invention is a manufacturing method of the glass substrate for flat panel glass which manufactures the glass substrate for flat panel glass by the float method, The shaping | molding process of shape | molding molten glass to a glass substrate on molten tin, and the said shape | molding by the said shaping | molding process A slow cooling process of slow cooling a glass substrate, The 1st supply process of spraying the inorganic substance containing an alkali metal on the surface of the side which contacts the said molten tin of the said glass substrate, and the said glass substrate after the said 1st supply process of a method for producing the glass substrate for a flat panel glass having a second supply step of spraying the SO ₂ gas to the surface of the side contacting the molten tin.

Glass Substrates for Flat Panel Glass, Float Method, Ag Colloidal Color

Description

The manufacturing method of the glass substrate for flat panel glass {PROCESS FOR PRODUCING GLASS SUBSTRATE FOR FLAT PANEL GLASS}

The present invention relates to a method for producing a glass substrate for flat panel glass.

In recent years, a flat panel display, especially a plasma display panel (hereinafter referred to as "PDP"), which is a kind of thin flat gas discharge display panel, has attracted attention as a thin and large flat panel color display device.

In the PDP, a cell is partitioned by a front glass substrate, a back glass substrate, and a partition wall. Plasma discharge is generated in this cell, and the phosphor layer on the inner wall of the cell emits light to form an image.

Generally, the float glass which is easy to enlarge a glass substrate, and is excellent in flatness and homogeneity, ie, the glass substrate formed on the molten tin by the float method, is used for the front glass substrate and the back glass substrate of PDP.

In addition, a transparent electrode containing ITO (indium-doped tin oxide) is formed on a surface (hereinafter referred to as an "top surface") on the side of the glass substrate used in the PDP that does not contact molten tin (hereinafter referred to as "top surface"). After apply | coating silver paste by the screen printing method, it bakes at 520-600 degreeC, and the silver electrode is formed.

However, when the silver paste is fired to form a silver electrode, the glass substrate yellows and the quality of the PDP color display deteriorates, specifically, a screen on which white is displayed has a yellowish color around the silver electrode, There was a problem that the luminance of the screen displaying blue was lowered.

This yellow coloration is reduced by Fe ²⁺ , Sn ^2+, etc., in which silver ions (Ag ⁺ ) diffused from the upper surface of the front glass substrate to the inside (surface layer) at the time of formation of the silver electrode are reduced to zero valent Ag ^0. It is considered that this is due to the color development of the colloid generated by aggregation (see Patent Documents 1 and 2, for example).

On the other hand, about the surface (henceforth a "lower surface") of the molten tin bath of a glass substrate manufactured by the float method including a PDP in contact with molten tin, it is conveyed by a roller after exiting a molten tin bath. It is necessary to prevent scratches from occurring. In order to achieve the object, sulfurous acid gas (SO ₂ gas) is sprayed and reacted with an alkali metal (for example, sodium) or alkaline earth metal (for example, calcium, etc.) present in the glass, A method of preventing scratches by forming a sulfate on the surface and functioning it as a protective film is known (see Patent Document 3, Non-Patent Document 1, etc.).

Patent Document 1: Japanese Patent Application Laid-Open No. 10-255669

Patent Document 2: Japanese Patent Laid-Open No. 2005-55669

Patent Document 3: International Publication No. 2002/051767

Non-Patent Document 1: U. Senturk etc, J. Non-Cryst. Solids, Vol. 222, p. 160 (1997)

<Start of invention>

Problems to be Solved by the Invention

The present inventors, the above-described Ag to be main cause entering back the upper surface of the SO ₂ gas is sprayed on the lower surface of the glass substrate is a glass substrate in order to form a result, the protective coating of extensive study further embodiment for the cause of the colloidal color development It turned out to be one of them.

That is, the SO ₂ gas enters the upper surface, whereby a protective film is formed on the upper surface, and at the same time, H ⁺ penetrates into the interior (surface layer) of the glass substrate from the upper surface, and as a result, at the time of electrode formation. It has been found that Ag ⁺ is easily introduced into the surface layer. Specifically, SO ₂ gas and water vapor in the atmosphere react to H ₂ SO ₃ (H ₂ O + SO ₂ → H ₂ SO ₃ ), and by substitution reaction of Na ⁺ and H ⁺ present in the surface layer (2Na ⁺ + H ₂ SO ₃ → 2H ⁺ + Na ₂ SO ₃ ) H ⁺ penetrates into the surface layer of the glass substrate, and Ag ⁺ is easily introduced into the surface layer during formation of the silver electrode by the exchange reaction between H ⁺ and Ag ⁺ . It turned out that

On the other hand, spraying SO ₂ gas on the lower surface of the glass substrate itself is a necessary treatment to some extent from the viewpoint of forming a glass protective film and preventing scratches of the glass substrate as described above.

Therefore, an object of this invention is to provide the manufacturing method of the glass substrate for flat panel glass which can prevent Ag colloid coloration, and the glass substrate for flat panel glass obtained by the said manufacturing method, maintaining favorable scratch resistance.

MEANS FOR SOLVING THE PROBLEMS [

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to achieve the said objective, in the manufacturing process by a float method, the inorganic material containing an alkali metal is sprayed on the lower surface and / or upper surface of a glass substrate, and an alkali metal is supplied, and then The present invention has been completed by discovering that spraying SO ₂ gas on the lower surface can prevent Ag colloidal color development while maintaining good scratch resistance.

That is, this invention provides the following (1)-(17).

(1) It is a manufacturing method of the glass substrate for flat panel glass which manufactures the glass substrate for flat panel glass by the float method,

A molding step of molding the molten glass onto a glass substrate on molten tin, and a slow cooling step of slowly cooling the glass substrate molded by the molding step,

A first supply step of spraying an inorganic substance containing an alkali metal on a surface of the glass substrate in contact with the molten tin and a surface of the glass substrate in contact with the molten tin after the first supply process. the method of the glass substrate for a flat panel glass having a second supply step of spraying the SO ₂ gas.

(2) It is a manufacturing method of the glass substrate for flat panel glass which manufactures the glass substrate for flat panel glass by the float method,

A molding step of molding the molten glass onto a glass substrate on molten tin, and a slow cooling step of slowly cooling the glass substrate molded by the molding step,

A first supply step of spraying an inorganic substance containing an alkali metal on a surface of the glass substrate that is not in contact with the molten tin, and a surface of the side that is in contact with the molten tin of the glass substrate after the first supply process a method for producing the glass substrate for a flat panel glass having a second supply step of spraying the SO ₂ gas.

(3) The method for producing a glass substrate for flat panel glass according to (1) or (2), wherein the first supply step is performed between the molding step and the slow cooling step.

(4) The method for producing a glass substrate for flat panel glass according to (1) or (2), wherein the first supply process is performed at a temperature in a glass transition point ± 100 ° C of the glass substrate.

(5) The manufacturing method of the glass substrate for flat panel glass of said (1) or (2) in which the said 1st supply process is performed at 550-750 degreeC.

(6) The method for producing a glass substrate for flat panel glass according to any one of the above (1) to (5), wherein the second supply step is performed between the molding step and the slow cooling step.

(7) The method for producing a glass substrate for flat panel glass according to any one of the above (1) to (5), wherein the second supply process is performed at a temperature in a glass transition point ± 100 ° C of the glass substrate.

(8) The manufacturing method of the glass substrate for flat panel glass in any one of said (1)-(5) whose said 2nd supply process is performed at 550-750 degreeC.

(9) It is a manufacturing method of the glass substrate for flat panel glass which manufactures the glass substrate for flat panel glass by the float method,

A molding step of molding the molten glass onto the glass substrate on the molten tin;

A first supply step of spraying an inorganic substance containing an alkali metal on a surface of the glass substrate in contact with the molten tin at 550 to 750 ° C., and the glass substrate at 550 to 750 ° C. after the first supply step. method of producing a glass substrate for a flat panel glass and a second supply step of spraying the SO ₂ gas to the surface of the side contacting the molten tin.

(10) It is a manufacturing method of the glass substrate for flat panel glass which manufactures the glass substrate for flat panel glass by the float method,

A molding step of molding the molten glass onto the glass substrate on the molten tin;

A first supply step of spraying an inorganic substance containing an alkali metal on a surface of the glass substrate at a side not in contact with the molten tin at 550 to 750 ° C., and the glass substrate at 550 to 750 ° C. after the first supply step in the production process of the glass substrate for a flat panel glass having a second supply step of spraying the SO ₂ gas to the surface of the side contacting the molten tin.

(11) The method for producing a glass substrate for flat panel glass according to any one of (1) to (10), wherein the inorganic substance containing the alkali metal contains sodium and boron.

(12) The method for producing a glass substrate for flat panel glass according to (11), wherein the inorganic substance containing the alkali metal is sodium tetraborate.

(13) The glass substrate for flat panel glass manufactured by the manufacturing method of said (11) or (12).

(14) It is a glass substrate for flat panel glass manufactured by the manufacturing method as described in said (11) or (12),

The glass substrate is expressed as a percentage of mass on an oxide basis,

SiO ₂ : 45-70%,

Al ₂ O ₃ : 0-20%,

CaO: 0-20%,

ZrO ₂ : 0-13%,

Total amount of alkaline earth metal oxide components: 5 to 40%,

Total amount of alkali metal oxide component: 5 to 30%

&Lt; / RTI &gt;

The average boron concentration of the surface on the side of the glass substrate in contact with the molten tin and / or the surface of the glass substrate in the side not in contact with the molten tin is 2 to 6 atomic%, and boron into the interior of the glass substrate. The glass substrate for flat panel glass whose diffusion depth of is 20-80 nm.

(15) The glass substrate for flat panel glass of the said (14) whose average H atom concentration to the depth of 0.1 micrometer from the surface of the glass substrate which does not contact the said molten tin is 2.5 mol% or less.

(16) It is a glass substrate for flat panel glass manufactured by the manufacturing method of said (11) or (12),

The glass substrate is expressed as a percentage of mass on an oxide basis,

SiO ₂ : 45-70%,

Al ₂ O ₃ : 0-20%,

CaO: 0-20%,

ZrO ₂ : 0-13%,

Total amount of alkaline earth metal oxide components: 5 to 40%,

Total amount of alkali metal oxide component: 5 to 30%

&Lt; / RTI &gt;

The glass substrate for flat panel glass whose average H atom concentration from the surface of the side of the said glass substrate which does not contact the said molten tin to 0.1 micrometer depth is 2.5 mol% or less.

(17) In the mass percentage indication on the basis of oxide,

SiO ₂ : 45-70%,

Al ₂ O ₃ : 0-20%,

CaO: 0-20%,

ZrO ₂ : 0-13%,

Total amount of alkaline earth metal oxide components: 5 to 40%,

Total amount of alkali metal oxide component: 5 to 30%

&Lt; / RTI &gt;

The glass substrate for flat panel glass whose average boron concentration of at least one surface is 2-6 atomic%, and the diffusion depth of boron from the said surface to the inside is 20-80 nm.

Effect of the Invention

As shown below, according to the present invention, a method for producing a glass substrate for flat panel glass capable of preventing Ag colloidal coloration while maintaining good scratch resistance and a glass substrate for flat panel glass obtained by the production method can be provided. Can be.

Furthermore, according to the present invention, not only PDP but also surface electric field display (FED (Field Emission Display)), surface conduction electron emission element display (SED (Surface-conduction Electron-emitter Display)), etc., maintains good scratch resistance. This is useful because it can prevent the development of Ag colloid.

FIG. 1: is a conceptual diagram which shows an example of the glass manufacturing line by a float method. FIG.

2 is a sectional view of a large tubular furnace used in the embodiment.

FIG. 3: is explanatory drawing which shows the part (wear part) which the abrasion ring of the taper experiment machine used for evaluation of abrasion resistance, and the number measurement site | part (measurement part) of a scratch.

<Brief description of symbols for the main parts of the drawings>

1: molten tin

2: molten tin bath

3: melting kiln

4: molten glass

5: withdraw roll

6: slow cooling furnace

11: large pipe furnace

12: quartz tube

13: glass substrate for flat panel glass

14: Alumina Bow

15: Reagent

16, 17: arrow

18: test body

19: wear parts

20: measuring unit

Best Mode for Carrying Out the Invention

The present invention is described in detail below.

The manufacturing method of the glass substrate for flat panel glass which concerns on the 1st aspect of this invention (henceforth "the 1st manufacturing method of this invention") is flat panel glass which manufactures the glass substrate for flat panel glass by the float method. It is a manufacturing method of the glass substrate for

A molding step of molding the molten glass onto a glass substrate on molten tin, and a slow cooling step of slowly cooling the glass substrate molded by the molding step,

A first supply step of spraying an inorganic material containing an alkali metal (hereinafter also referred to as an " alkali metal-containing inorganic material &quot;) on a surface of the glass substrate in contact with the molten tin; and after the first supply step, surface of the side contacting the molten tin in the glass substrate, that is, a method for manufacturing a glass substrate for a flat panel glass and a second supplying step in which the inorganic material spraying the SO ₂ gas to the atomizing surface.

Moreover, the manufacturing method (henceforth "the 2nd manufacturing method of this invention") of the glass substrate for flat panel glass which concerns on the 2nd aspect of this invention is the flat which manufactures the glass substrate for flat panel glass by the float method. It is a manufacturing method of the glass substrate for panel glass,

A molding step of molding the molten glass onto a glass substrate on molten tin, and a slow cooling step of slowly cooling the glass substrate molded by the molding step,

A first supply step of spraying an inorganic substance containing an alkali metal on a surface of the glass substrate that is not in contact with the molten tin, and a surface of the side that is in contact with the molten tin of the glass substrate after the first supply process to a method for manufacturing a glass substrate for a flat panel glass and a second supply step of spraying the SO ₂ gas.

Next, the shaping | molding process, slow cooling process, 1st supply process in the 1st manufacturing method of this invention, and the 2nd manufacturing method (Hereafter, it calls it "the manufacturing method of this invention" unless otherwise indicated.) A 2nd supply process is explained in full detail.

[Molding process]

The said molding process is a process of shape | molding a molten glass on a glass substrate on molten tin in a molten tin bath, and is a conventionally well-known process in the general float method.

1 is a conceptual diagram illustrating an example of a glass production line by the float method.

As shown in FIG. 1, in the float method, first, the molten glass 4 flows in continuously from the molten kiln 3 on the bath surface of the molten tin bath 2 which satisfy | filled the molten tin 1, and is glass. Ribbon is formed. Next, by advancing the glass ribbon while floating along the bath surface of the molten tin bath 2, the glass ribbon is molded into a plate shape at the same time as the temperature decreases. Then, the produced glass substrate is taken out by the take-out roll 5, and is conveyed to the slow cooling furnace 6 in the continuous state in the longitudinal direction.

Here, in FIG. 1, the said molding process is a process until the molten glass 4 is shape | molded in plate shape via a glass ribbon.

In the present invention, similarly to the general float method, the molten tin bath 2 is composed of a tin bath in which the inside of the metal case is lined with special refractory and a ceiling, and a sealed structure is used to prevent oxidation of tin. As an atmosphere gas in a molten tin bath, the mixed gas containing hydrogen and nitrogen (content of hydrogen is 2-10 volume%) can be used.

Moreover, the temperature conditions in the molten tin bath of the said shaping | molding process are 600-1050 degreeC similarly to the general float method, ie, the temperature of the molten glass which flows into a molten tin bath is 900-1050 degreeC in an upstream, and 600 in a downstream side. To 800 ° C. In addition, although this temperature is normally maintained by the amount of heat of a molten glass, you may use a heater and a cooler for temperature control.

Since the manufacturing method of this invention is a method of manufacturing the glass substrate for flat panel glass, the glass substrate shape | molded on molten tin is the mass percentage display of an oxide reference | standard,

SiO ₂ : 45-70%,

Al ₂ O ₃ : 0-20%,

CaO: 0-20%,

ZrO ₂ : 0-13%,

Total amount of alkaline earth metal oxide components: 5 to 40%,

Total amount of alkali metal oxide component: 5 to 30%

It is preferable that it is a composition containing.

In this invention, the glass substrate shape | molded on molten tin is the mass percentage display of an oxide reference | standard,

SiO ₂ : 50 to 65%,

Al ₂ O ₃ : 0% to 15%,

MgO: 0-15%,

CaO: 0-15%,

SrO: 0-20%,

BaO: 0-20%,

ZrO ₂ : 0-13%,

Total amount of alkaline earth metal oxide components: 5 to 40%,

Total amount of alkali metal oxide component: 5 to 30%

It is more preferable that it is a composition containing.

In addition, in this invention, the glass substrate shape | molded on molten tin is the mass percentage display of an oxide reference | standard,

SiO ₂ : 50 to 65%,

Al ₂ O ₃ : 2-15%,

MgO: 0-15%,

CaO: 0-15%,

SrO: 0-20%,

BaO: 0-20%,

ZrO ₂ : 0 to 6%,

Total amount of alkaline earth metal oxide components: 10 to 30%,

Total amount of alkali metal oxide component: 6-15%

It is more preferable that it is a composition containing.

In addition, in this invention, the glass substrate shape | molded on molten tin is the mass percentage display of an oxide reference | standard,

SiO ₂ : 52-62%,

Al ₂ O ₃ : 5-12%,

MgO: 0 to 5%,

CaO: 3-12%,

SrO: 4-18%,

BaO: 0 to 13%,

ZrO ₂ : 0 to 6%,

Total amount of alkaline earth metal oxide components: 15 to 30%,

Total amount of alkali metal oxide component: 6 to 14%

It is especially preferable that it is a composition containing.

In addition, in this invention, the glass substrate shape | molded on molten tin is the mass percentage display of an oxide reference | standard,

SiO ₂ : 52-62%,

Al ₂ O ₃ : 5-12%,

MgO: 0-4%,

CaO: 3 to 5.5%,

SrO: 6-9%,

BaO: 0 to 13%,

ZrO ₂ : 0.2-6%,

Total amount of alkaline earth metal oxide components: 17 to 27%,

Total amount of alkali metal oxide component: 7 to 14%

It is most preferable that it is a composition containing.

In this invention, it is preferable that the thickness of the glass substrate shape | molded on molten tin is 1-3 mm from a viewpoint of intensity | strength and transmittance | permeability.

[Slow cooling process]

The slow cooling step is a step of slowly cooling the glass substrate molded by the molding step.

Here, in FIG. 1, the said slow cooling process is a process to take out the manufactured glass substrate with the takeout roll 5, and to carry it to the slow cooling furnace 6 in the continuous state in the longitudinal direction, and to cool slowly.

In the present invention, the same slow cooling furnace as that used by a general float method can be used, and a heater or the like can be provided for temperature control.

In addition, the slow cooling conditions in the slow cooling furnace of the slow cooling process can be made into the temperature of 550-750 degreeC at the inlet of a slow cooling furnace and 200-300 degreeC at the outlet like the general float method, and the speed | rate of a temperature drop is 90 It can be set to ° C ± 10 ° C / m.

[First Supply Process]

In the first manufacturing method of the present invention, the first supply step is a step of spraying an alkali metal-containing inorganic material on the lower surface of the glass substrate to supply the alkali metal to the lower surface (hereinafter referred to as "first supply process ( First manufacturing method) ".

Flat panel glass which can prevent Ag colloidal coloration while maintaining good scratch resistance by supplying alkali metal to the lower surface of the glass substrate using an alkali metal-containing inorganic substance in a first supply process (first manufacturing method). The manufacturing method of the glass substrate for this can be provided.

This is considered to be because the SO ₂ gas sprayed by the second supply step described later preferentially reacts with the alkali metal supplied to the lower surface, thereby preventing returning to the upper surface of the glass substrate.

In addition, by supplying an alkali metal to the lower surface of the glass substrate by using an alkali metal-containing inorganic substance, it is possible to suppress the formation of sulfates (for example, calcium sulfate, strontium sulfate, etc.) derived from alkaline earth metals, Since the protective film of sulfate (for example, sodium sulfate etc.) can be produced efficiently, the amount of SO ₂ gas used can also be reduced. In addition, sulfates of alkaline earth metals such as calcium sulfate and strontium sulfate are poorly soluble substances which are difficult to dissolve in water, and are not preferable as reactive organisms.

On the other hand, in the second manufacturing method of the present invention, the first supplying step is a step of spraying an inorganic material containing an alkali metal on the upper surface of the glass substrate to supply the alkali metal to the upper surface (hereinafter, "manufactured by" 1 supply process (second manufacturing method) ".

In the first supply step (second manufacturing method), an alkali metal is supplied to the upper surface of the glass substrate by using an alkali metal-containing inorganic substance, whereby the Ag colloidal color can be prevented. Can be provided.

The alkali metal-containing inorganic substance herein refers to an inorganic substance containing an alkali metal as described above, and for example, an inorganic substance containing lithium (Li), sodium (Na), potassium (K), cesium (Cs), or the like. This corresponds.

As the inorganic substance containing Na, specifically, for example, NaOH, Na ₂ S, NaCl, NaF, NaBr, NaI, soda ash, NaNH ₂ , sodium benzyloxide, NaBH ₄ , NaCN, NaNO ₃ , Na ₂ B ₄ O ₇ -10H ₂ O (sodium tetraborate decahydrate), Na ₂ B ₄ O ₇ , (C ₂ H ₅ ) ₄ BNa, and the like, and these may be used alone or in combination of two or more thereof. It can also be used in combination.

As the inorganic substance containing K, specifically, for example, KOH, KCl, KF, KBr, KI, KCN, K ₂ CO ₃ , potassium gluconate, KHF ₂ , KNO ₃ , K ₂ B ₄ O ₇ − 4H ₂ O may be made of (potassium tetraborate tetrahydrate), such as _{K 2 B 4 O 7, KBF} 4, and these may be used alone or may be used in combination of two or more.

Specific examples of the inorganic substance containing Cs include CsOH, CsCl, CsF, CsBr, CsI, cesium acetylacetonate, HCO ₂ Cs, CsNO ₃ , and the like, and these may be used alone. In addition, you may use 2 or more types together.

An alkali metal-containing inorganic substance is preferable from the reason shown below that it is an inorganic substance containing Na.

That is, in the 1st manufacturing method of this invention, since the production efficiency of the protective film (sodium sulfate) formed in the 2nd supply process mentioned later can be improved more, As a result, Ag colloid color development can be prevented more preferable.

Especially, since the alkali metal containing inorganic substance is an inorganic substance containing Na and boron, since the glass substrate for flat panel glass obtained by the manufacturing method of this invention becomes more wear-resistant, it is more preferable. Specifically, the alkali metal-containing inorganic substance is preferably Na ₂ B ₄ O ₇ -10H ₂ O, Na ₂ B ₄ O ₇ , and more preferably Na ₂ B ₄ O ₇ -10H ₂ O.

As a result of supplying not only Na but also boron by spraying an inorganic material containing Na and boron, boron diffuses from the lower surface into the glass substrate, and the strength of the glass substrate itself is improved.

For this reason, in addition to the glass substrate for flat panel glass, a high level of scratch resistance can be satisfied by using this boron diffusion with respect to the glass substrate for DNA chips, the glass substrate for microchips and biochips, etc., for example.

Although the said 1st supply process supplies an alkali metal to these surfaces by spraying such an alkali metal containing inorganic substance to the lower surface or upper surface of the said glass substrate, About the timing (timing) and the spraying method of this spraying of the following: The aspect shown to is illustrated preferably.

The timing for spraying the alkali metal-containing inorganic substance is not particularly limited as long as both the first supply process (first production method) and the first supply process (second production method) are before the second supply process described later. Although it may be simultaneous with the said shaping | molding process, and may be simultaneous with the slow cooling process mentioned later, it is preferable that it is between the said shaping | molding process and the said slow cooling process, since it can suppress the generation | occurrence | production of the flaw of the lower surface of a glass substrate more.

The term "simultaneous to the molding process" herein means a step immediately after the glass substrate is formed in the molding process and included in the molding process, for example, a molten tin bath (float bath) in the forming furnace and an outlet portion of the entire furnace (shield rare). ) Is installed, it means that the spray can also be sprayed on the shield rare. In addition, "simultaneous with a slow cooling process" means that it can also spray in the vicinity of the inlet of a slow cooling furnace, or upstream of a slow cooling furnace. In addition, "between the said molding process and the said slow cooling process" means that it can also spray between a formation furnace and a slow cooling furnace, conveying a glass substrate.

On the other hand, in the method of spraying the alkali metal-containing inorganic substance, both the first supply process (the first production method) and the first supply process (the second production method), for example, heat and vaporize the alkali metal-containing inorganic material. And spraying the vaporized material onto the lower or upper surface of the glass substrate using a nozzle; The method of heat-vaporizing an alkali metal containing inorganic substance by heater heating, infrared lamp heating, laser heating, etc. are mentioned preferably.

In addition, the spraying of the vaporized substance is preferably carried out at a temperature in the range of the glass transition point ± 100 ℃ of the glass substrate. In particular, it is preferable that it is the range of glass transition point -30 degreeC-glass transition point +100 degreeC of a glass substrate. This is because when the spraying is carried out in this temperature range, the glass becomes soft at the glass transition point, and thus, the formation of a film in that area can prevent the scratches from occurring more effectively.

Specifically, it is preferable to carry out at 550-750 degreeC from the point that a substrate temperature does not fall rapidly when a vaporized substance vaporizes efficiently and is sprayed on the glass substrate surface.

In addition, the spray amount of a vaporizing substance may be either a 1st supply process (1st manufacturing method) and a 1st supply process (2nd manufacturing method), It is preferable that it is 0.2-10 L / m <2>, It is 0.2-3 L It is more preferable that it is / m <2>, and it is especially preferable that it is 0.2-1 L / m <2>. In the first manufacturing method of the present invention, if the spraying amount is within the above range, the supplying amount of alkali metal supplied to the lower surface of the glass substrate is sufficient, and a protective film formed by reacting with SO ₂ gas sprayed in the second supplying step to be described later. The production efficiency of is further improved. Moreover, since the diffusion of boric acid to a glass substrate advances efficiently in the 2nd manufacturing method of this invention as the spray amount is the said range, it becomes possible to improve abrasion resistance efficiently.

When sodium tetraborate decahydrate is used as the alkali metal-containing inorganic substance, it is used at a temperature of about 850 ° C. in a furnace for forming a glass substrate and a furnace other than a slow cooling furnace (for example, a large tubular furnace used in the examples). After evaporating the sodium borate, the vaporizing material is sprayed onto a forming furnace or slow cooling furnace or a lower surface or upper surface of the glass substrate to be conveyed between the furnaces using a nozzle, and the like, and the like is a preferred embodiment. It can be mentioned as.

By spraying the said alkali metal containing inorganic substance by this method, an alkali metal is supplied to the lower surface or upper surface of the said glass substrate. The presence of an alkali metal on the lower surface or the upper surface of the glass substrate can be confirmed by analyzing the lower surface of the glass substrate by X-ray photoelectron spectroscopy (XPS) or fluorescent X-ray analysis.

Second Supply Process

In the first manufacturing method of the present invention, the second supply step sprays SO ₂ gas on the lower surface of the glass substrate supplied with the alkali metal after the first supply process to form a protective film on the lower surface. (Hereinafter also referred to as "second supply process (first production method)").

This 2nd supply process (1st manufacturing method) differs from the conventionally well-known process in the general float method in that a protective film is formed in the lower surface of the said glass substrate to which the said alkali metal was supplied.

That is, the second supply process (first manufacturing method) causes the alkali metal and the SO ₂ gas to react by spraying SO ₂ gas on the lower surface of the glass substrate supplied with the alkali metal by the first supply process, It is a process of forming the protective film containing an alkali sulfate (for example, sodium sulfate etc.) in the lower surface of the said glass substrate.

On the other hand, in the second manufacturing method of the present invention, the second supply step is a step of spraying SO ₂ gas on the lower surface of the glass substrate after the first supply process to form a protective film on the lower surface (hereinafter, "The 2nd supply process (2nd manufacturing method)", and the same process as the conventionally known process in the general float method.

Wherein the embodiments described below both for spray time (timing) and the spraying of the SO ₂ gas method according to the second supplying step and the second supply process (first method) and a second supply step (the second method) is preferred Is illustrated.

The time for spraying the SO ₂ gas is not particularly limited as long as it is later than the first supply step, but is preferably immediately after the first supply step from the viewpoint of preventing scratches on the surface of the glass substrate during transport. It is more preferable that it is between the said slow cooling processes. Moreover, spraying each gas simultaneously is not preferable because each gas reacts and formation of a film becomes difficult.

On the other hand, a method of spraying the SO ₂ gas can be carried out by conventional methods known to a method similar to in the general float method. Specifically, it can implement by the method (for example, the method of Claim 12 of patent document 3) sprayed from the nozzle provided below the glass substrate in the width direction of a glass substrate.

However, in the 1st manufacturing method of this invention, compared with the conventional example which can also use the sulfate (for example, calcium sulfate) derived from alkaline-earth metal as a protective film of the glass substrate for flat panel glass, the equivalent protective effect is achieved. It is possible to reduce the spray amount of the SO ₂ gas while ensuring. As described above, it is considered that the SO ₂ gas sprayed by the second supply process preferentially reacts with the alkali metal supplied to the lower surface, and the reaction with alkaline earth metals (Ca, Sr, etc.) is suppressed. Specifically, in the first production method of the present invention, the spray amount of the SO ₂ gas can be reduced to 0.05 to 2.5 L / m 2, particularly to 0.05 to 0.3 L / m 2.

Further, the spraying of the SO ₂ gas is preferably carried out at a temperature in the range of the glass transition point ± 100 ° C of the glass substrate, more preferably at 550 to 750 ° C. When spraying is performed at this temperature, the production efficiency of the protective film is further improved, and as a result, Ag colloidal color development can be more prevented.

Although the manufacturing method of this invention is a manufacturing method of the glass substrate for flat panel glass provided with the shaping | molding process, slow cooling process, the 1st supply process, and the 2nd supply process which were mentioned above, you may further comprise the washing | cleaning process shown below.

(Cleaning process)

In the manufacturing method of this invention, it is also possible to provide the washing | cleaning process which wash | cleans and removes the protective film formed by the said 2nd supply process as needed in order to perform defect inspection of foam | bubble, a foreign material, a scratch, etc., and to obtain high permeability. have.

This washing | cleaning process is a conventionally well-known process in a general float method, About the timing (timing) and a washing | cleaning method, the aspect shown below is illustrated preferably.

Although the timing of the said washing process is not specifically limited if it is after the said 2nd supply process, but since the protective film was made with respect to the flaw to the surface (lower surface) of the glass substrate which arises during roller conveyance, the last step of the said slow cooling process Or it is preferable just after the said slow cooling process.

On the other hand, the cleaning method in the cleaning step can be removed by an easy method since a protective film containing a sulfate (for example, a water-soluble salt such as sodium sulfate) derived from an alkali metal is formed in the present invention. For example, it can remove by water washing process. In addition, when SO ₂ gas is sprayed without performing the said 1st supply process, the protective film formed in the lower surface of a glass substrate is a sulfate (for example, hardly water-soluble salts, such as calcium sulfate) derived from alkaline earth metals. It becomes difficult to wash easily.

The manufacturing method of the glass substrate for flat panel glass which concerns on the 3rd aspect of this invention (henceforth "the 3rd manufacturing method of this invention") is for flat panel glass which manufactures the glass substrate for flat panel glass by the float method. It is a manufacturing method of a glass substrate,

A molding step of molding the molten glass onto the glass substrate on the molten tin;

A first supply step of spraying an inorganic substance containing an alkali metal on a surface of the glass substrate in contact with the molten tin at 550 to 750 ° C., and the glass substrate at 550 to 750 ° C. after the first supply step. a manufacturing method of a glass substrate for a flat panel glass having a second supply step of spraying the SO ₂ gas to the surface of the side contacting the molten tin.

Here, the shaping | molding process in the 3rd manufacturing method of this invention is the same as what was demonstrated in the manufacturing method of this invention, and the thing which prescribed | regulated temperature to 550-750 degreeC also about a 1st supply process and a 2nd supply process. Other than that is the same as what was demonstrated in the 1st manufacturing method of this invention. Moreover, also in the 3rd manufacturing method of this invention, you may further provide the said washing process.

In addition, the manufacturing method of the glass substrate for flat panel glass which concerns on the 4th aspect of this invention (henceforth "the 4th manufacturing method of this invention") is a flat panel which manufactures the glass substrate for flat panel glass by the float method. It is a manufacturing method of the glass substrate for glass,

A molding step of molding the molten glass onto the glass substrate on the molten tin;

A first supply step of spraying an inorganic substance containing an alkali metal on a surface of the glass substrate at a side not in contact with the molten tin at 550 to 750 ° C., and the glass substrate at 550 to 750 ° C. after the first supply step of a manufacturing method of a glass substrate for a flat panel glass having a second supply step of spraying the SO ₂ gas to the surface of the side contacting the molten tin.

Here, the shaping | molding process in the 4th manufacturing method of this invention is the same as what was demonstrated in the manufacturing method of this invention, except having prescribed | regulated temperature to 550-750 degreeC also about a 1st supply process and a 2nd supply process. Is the same as that described in the second manufacturing method of the present invention. Moreover, also in the 4th manufacturing method of this invention, you may further provide the said washing process.

This invention provides the glass substrate for flat panel glass obtained by these methods, when the inorganic substance containing Na and boron is used in the 4th manufacturing method from the 1st manufacturing method of this invention.

Specifically, an inorganic material containing Na and boron is sprayed onto the lower surface and / or the upper surface of the glass substrate in the first supply process, and then the cleaning process is performed as necessary, followed by the glass substrate for flat panel glass. Can be provided.

It is preferable that the glass substrate for flat panel glass of this invention is the following compositions.

That is, in the glass substrate for flat panel glass of this invention, the said glass substrate is the mass percentage display of an oxide basis,

SiO ₂ : 45-70%,

Al ₂ O ₃ : 0-20%,

CaO: 0-20%,

ZrO ₂ : 0-13%,

Total amount of alkaline earth metal oxide components: 5 to 40%,

Total amount of alkali metal oxide component: 5 to 30%

&Lt; / RTI &gt;

The average boron concentration of the lower surface and / or the upper surface of the glass substrate, preferably the upper surface, is 2 to 6 atomic%, preferably 2 to 4 atomic%, and the diffusion depth of boron into the glass substrate is 20 to 80 nm, preferably 30 to 50 nm.

Moreover, as another specific composition, the composition similar to what was mentioned above as a composition of the glass substrate shape | molded on molten tin is mentioned.

In this invention, the average boron concentration of the said lower surface or upper surface of the said glass substrate can be calculated | required as an average value at the time of measuring five points arbitrarily by X-ray photoelectron spectroscopy.

In the X-ray photoelectron spectroscopy, an X-ray AlKα ray monochromated with a monochromator was used as an X-ray source using an XPS spectrometer (5500 type, manufactured by PHI). In addition, the detection angle of the X-ray photoelectron was 75 degrees, and the measurement was performed by irradiating an electronic shower for charge correction.

In the present invention, the depth of diffusion of boron into the glass substrate can be approximated from the depth reaching the same level of secondary ionic strength as the background by secondary ion mass spectrometry (SIMS).

Specifically, 5 points of diffusion depths were measured at 5 points on the glass substrate by the secondary ion mass spectrometer (ADEPT1010, Albag Pai Co., Ltd.), respectively, and the average value was calculated | required.

Here, conversion of the sputtering time to the sputtering depth was performed in terms of SiO ₂ (4 nm = 1 min). In addition, the primary ion was measured under an oxygen ion beam, the acceleration voltage was 5 keV, the beam current was 400 nA, the incident angle of the primary ion was 45 degrees with respect to the normal of the sample surface, and the beam scanning range was 400 × 400 μm ² . .

In the glass substrate for flat panel glass of this invention, the average boron concentration of the lower surface or upper surface of the said glass substrate is 2-6 atomic%, Preferably it is 2-4 atomic%, and the boron inside the said glass substrate Since the diffusion depth is 20 to 80 nm, preferably 30 to 50 nm, the strength of the glass substrate itself is improved, the wear resistance is excellent, and the scratch resistance is also excellent in the transport and processing steps after the protective film is removed. The reason that boron diffuses from the lower surface or the upper surface into the glass substrate and remains in the surface layer of the glass substrate is considered to be because the network structure of the glass is firm.

In the glass substrate for flat panel glass of this invention, since boron remains in the surface layer of a glass substrate not only before performing the said washing process but also after performing the said washing process as needed, the generation | occurrence | production of the back surface of a glass substrate is suppressed continuously. It is preferable because it can be done.

Moreover, in the glass substrate for flat panel glass of this invention, that boron remains in the surface layer of a glass substrate is easy to enter boron into the inside of a glass substrate by the said 1st supply process, and it is easy to remain in the surface layer of a glass substrate. I guess it is because of the reason.

Moreover, it is preferable that the average H atom concentration from the upper surface of the said glass substrate to the depth of 0.1 micrometer is 2.5 mol% or less, and, as for the glass substrate for flat panel glass of this invention, it is more preferable that it is 2.0 mol% or less. If the average H atom concentration is in this range, the chance of the above-described exchange reaction between Ag ⁺ and H ⁺ occurs is reduced, Ag ⁺ is not introduced into the surface layer during formation of the silver electrode, and Ag colloidal color can be more prevented.

Here, the average H atom concentration from the upper surface of the glass substrate to the depth of 0.1 µm is 5 between the upper surface and the depth of 0.1 µm using a secondary ion mass spectrometer (ADEPT1010, manufactured by Albag Pai). It can measure about a point and can obtain | require as an average value. In addition, primary ions can be measured under conditions of Cs ⁺ , acceleration voltage of 5 keV, beam current of 400 nA, primary ion of 60 degrees with respect to the normal of the sample surface, and beam scanning range of 200 x 200 μm ² . Can be.

Therefore, the present invention is expressed in terms of mass percentage based on oxide,

SiO ₂ : 45-70%,

Al ₂ O ₃ : 0-20%,

CaO: 0-20%,

ZrO ₂ : 0-13%,

Total amount of alkaline earth metal oxide components: 5 to 40%,

Total amount of alkali metal oxide component: 5 to 30%

&Lt; / RTI &gt;

The glass substrate for flat panel glass whose average boron concentration of at least one surface is 2-6 atomic%, and the diffusion depth of boron from the said surface to the inside is 20-80 nm can also be provided.

Although an Example is given to the following and this invention is concretely demonstrated to it, this invention is not limited to this.

(Example 1)

The experimental apparatus shown in FIG. 2 was used. 2 is a cross-sectional view of the large tubular furnace used in the embodiment.

Specifically, the quartz tube 12 is provided in the large tubular furnace 11 whose temperature can be adjusted, and the glass substrate 13 for flat panel glass (10 cm each side) of thickness 2.8 mm is placed in the quartz tube 12. The large tubular furnace 11 was heated to 600 ° C. Here, as the "flat panel glass substrate for a glass", by mass percentage display of the oxide _{basis, SiO 2: 58.6, Al 2} O 3: 6.9, MgO: 1.9, CaO: 4.8, SrO: 6.9, BaO: 7.9, Na 2 A glass having a composition of O: 4.0, K ₂ O: 6.1, ZrO ₂ : 2.8, and Fe ₂ O ₃ : 0.09 was used. In addition, the glass transition point of the said glass is 600 degreeC.

Subsequently, the reagent 15 of sodium tetraborate decahydrate placed in the alumina boat 14 is locally heated to about 850 ° C. to vaporize, and the vaporized substance is sprayed from the end of the quartz tube in the direction indicated by the arrow 16. Thus, sodium tetraborate was supplied to the surface (lower surface) of the glass substrate 13 for flat panel glass. At this time, the spray amount of sodium tetraborate decahydrate was 0.4 L / m <2>, and the temperature of the glass substrate 13 for flat panel glass was 600 degreeC.

Next, SO ₂ gas is sprayed in the direction indicated by the arrow 17 so that the spray amount to the surface (lower surface) of the glass substrate 13 for flat panel glass supplied with sodium is 0.1 L / m ₂ , thereby forming a protective film. The glass substrate for flat panel glass with a protective film was produced. The temperature of the glass substrate 13 for flat panel glass at this time was 600 degreeC.

In addition, the present embodiment is the same as the condition of spraying the alkali metal-containing inorganic material between the forming step and the slow cooling step, and spraying the SO ₂ gas immediately.

(Example 2)

A glass substrate for a flat panel glass with a protective coating was produced in the same manner as in Example 1 except that the spray amount of the SO ₂ gas was 0.4 L / m 2.

(Example 3)

A glass substrate for a flat panel glass with a protective coating was produced in the same manner as in Example 1 except that the spray amount of the SO ₂ gas was 1.0 L / m 2.

(Comparative Example 1)

A glass substrate for a flat panel glass with a protective coating was produced in the same manner as in Example 1 except that only SO ₂ gas was sprayed without using sodium tetraborate.

(Comparative Example 2)

A glass substrate for a flat panel glass with a protective coating was produced in the same manner as in Example 2 except that only SO ₂ gas was sprayed without using sodium tetraborate.

(Comparative Example 3)

A glass substrate for a flat panel glass with a protective coating was produced in the same manner as in Example 3 except that only SO ₂ gas was sprayed without using sodium tetraborate.

(Comparative Example 4)

A glass substrate for a flat panel glass was produced in the same manner as in Example 1, except that sodium tetraborate was not used and SO ₂ gas was not sprayed, but was simply heated at 700 ° C. for 15 minutes.

(Comparative Example 5)

A glass substrate for flat panel glass was produced in the same manner as in Example 1 except that sodium tetraborate was not used and SO ₂ gas was not sprayed.

About the glass substrate for flat panel glass with each protective film obtained by Examples 1-3 and Comparative Examples 1-3, the adhesion amount of a protective film, abrasion resistance, average boron concentration-diffusion depth, average H atom concentration of an upper surface, Yellowness and wear resistance of the upper surface were measured and evaluated by the method shown below. The results are shown in Table 1 below.

Since In Comparative Example 4, and for each of the flat panel glass substrate obtained from glass 5, not to form the protective film without having to spray the SO ₂ gas was measured by the method shown below is representative of the wear resistance. The results are shown in Table 1.

<Protective film adhesion amount>

The protective film of the obtained glass substrate for flat panel glass with each protective film was dissolved in pure water, sulfur was quantified using ICP emission spectrometry, and sodium, calcium and strontium were quantified using atomic absorption method.

From these quantitative values, the amount of sulfate adhered to the lower surface was calculated as the amount of adhesion of the protective film. In addition, this adhesion amount was calculated | required as an average value computed from 10 sheets of the glass substrate for flat panel glass with a protective film obtained.

<Scratch resistance>

Evaluation of scratch resistance was performed by the taper test based on JISR3221 (1990). In addition, the taper test was carried out using a taper tester (Tdedyne Taber Model 503), the wear ring is fixed to CS-10F, the load is 250g, the number of wear is fixed three times.

Then, in order to remove the protective film of the glass substrate for flat panel glass with each protective film used as a test body, the board | substrate was washed with water for 30 second in 30 degreeC water flow (3 L / min) in order to remove the protective film.

The surface of the glass substrate obtained by removing the protective film was observed under a microscope, and the number of scratches (the number of scratches) whose length in the major axis direction existing within 1 cm x 1 cm of each side was 0.2 mm or more was measured. The measurement part was the center part of the site | part provided for the taper test (refer FIG. 3). In FIG. 3, although the abrasion part 19 by a wear wheel is formed in the test body (glass substrate for flat panel glass) 18, the measurement part 20 becomes a center part of the abrasion part 19. In FIG.

In addition, the measurement of the number of scratches was performed about arbitrary ten points with respect to each glass substrate, and the average value was calculated | required. Furthermore, the number of scratches was calculated | required as the average value computed from 10 sheets of the obtained glass substrate.

<Average Boron Concentration-Diffusion Depth>

(1) The obtained glass substrate for flat panel glass with each protective film was washed with water at the place where 20 degreeC pure water (flow rate: 3 L / min) flows, and the protective film was removed. Then, the average boron concentration of the glass substrate lower surface after washing was calculated | required as an average value when 5-point measurement was carried out by X-ray photoelectron spectroscopy. In the X-ray photoelectron spectroscopy, an XPS spectrometer (5500 type, manufactured by PHI Co., Ltd.) was used to make an X-ray AlKα ray monochromated with a monochromator as an X-ray source. In addition, the detection angle of the X-ray photoelectron was 75 degrees, and the measurement was performed by irradiating an electronic shower for charge correction.

In the following Table 1, although the column of the average boron concentration of Comparative Examples 1-3 is "-", it shows that boron was not detectable.

(2) The diffusion depth of boron into the glass substrate was estimated from the depth reached by the secondary ion mass spectrometry (SIMS) at the secondary ion intensity at the same level as the background.

Specifically, 5 points of diffusion depths were measured at 5 points on the glass substrate after washing | cleaning by the secondary ion mass spectrometer (ADEPT1010, Albag Pai Co., Ltd.), respectively, and the average value was calculated | required. Here, conversion of the sputtering time to the sputtering depth was performed in terms of SiO ₂ (4 nm = 1 min).

In addition, the primary ion is measured under an oxygen ion beam, the acceleration voltage is 5 keV, the beam current is 400 nA, the incident angle of the primary ion is 45 degrees with respect to the normal of the sample surface, and the beam scanning range is 400 × 400 μm ² . It was.

In the following Table 1, although the column of the diffusion depth of Comparative Examples 1-3 is "-", it shows that a diffusion cannot be confirmed.

<Average H atom concentration in the upper surface>

The average H atom concentration from the upper surface of the glass substrate of the glass substrate for flat panel glass with each obtained protective film to a depth of 0.1 micrometer was used for the upper surface using a secondary ion mass spectrometer (ADEPT1010, Albag Pai Corporation). It measured about five points from to to depth of 0.1 micrometer, and calculated | required as the average value. The primary ions were measured under Cs ⁺ , the acceleration voltage was 5 keV, the beam current was 400 nA, the incidence angle of the primary ions was 60 degrees with respect to the normal of the sample surface, and the beam scanning range was 200 × 200 μm ² . .

<Yellow degree of upper surface (b *)>

The yellowness of the upper surface of the obtained glass substrate for flat panel glass with each protective film was a sample (Ag was applied to the upper surface with a thickness of 20 μm, dried at 110 ° C. for 20 minutes, fired at 560 ° C. for 60 minutes, and cooled. And Ag removed with nitric acid) were measured according to JIS-Z8729 with a Hitachi Seisakusho magnetic spectrophotometer (type U-3500). In addition, the thermal expansion coefficient of 50-350 degreeC was 83 * 10 <^-7> / degreeC, and the distortion point was measured on condition of 570 degreeC.

<Wear resistance>

Wear resistance was performed by examining the change rate (haze change rate) of the haze rate before and after a taper test.

First, the haze rate of each obtained glass substrate for flat panel glass was measured with the haze meter.

Next, about each obtained glass substrate for flat panel glass, the taper test according to JIS R3221 (1990) was done. In addition, the taper test was performed using the taper tester (Tdedyne Taber Model 503), the wear ring was fixed to CS-10F, and the load was fixed at 500g.

Next, the haze rate after 1000 times of taper wear was measured by a haze meter, and the rate of change thereof was determined from the haze rate before the taper test.

Here, the haze value is defined by the scattered light Td and the transmitted light Tt as in the following equation.

Haze rate = (Td / Tt) × 100%

In addition, the change rate (DELTA) H of the haze rate H is represented by the following formula.

Haze rate H before ΔH = 1000 times of abrasion test

From the results shown in Table 1, preferably to more than equal to the tetraborate Examples 1-3 flat panel glass substrate side of the Comparative Examples 1 to 3 equal to less than the SO ₂ gas spray amount even abrasion resistance as compared to for the obtained using a sodium It was found that yellowness of the upper surface, that is, color development of Ag colloid can be suppressed.

Moreover, even if the same amount of sodium sulfate adhered, that is, even if it compares Example 1 and Comparative Example 2, it turns out that the glass substrate for flat panel glass of Example 1 obtained using sodium tetraborate reduced the number of scratches. Can be. This is because the friction resistance of the glass substrate itself improved because boron diffused into the glass substrate.

Moreover, the glass substrate for flat panel glass of Examples 1-3 was confirmed that the protective film formed in the surface of the glass substrate was removed after normal water washing, and the clean surface was shown. On the other hand, as a glass substrate for flat panel glass of Comparative Examples 1-3, the protective film formed in the surface of the glass substrate was not removed even if normal water washing was carried out. In addition, when the component of the film | membrane which remained was measured, it was calcium sulfate and strontium sulfate.

Moreover, as for the glass substrates for flat panel glass of Examples 1-3, since a boron spread | diffused, it turned out that haze change rate decreases and wear resistance is also improved compared with the glass substrates for flat panel glass of Comparative Examples 1-5.

Although this invention was detailed also demonstrated with reference to the specific embodiment, it is clear for those skilled in the art that various changes and correction can be added without deviating from the mind and range of this invention.

This application is based on the JP Patent application (Japanese Patent Application 2006-188036) of an July, 2006 application, The content is taken in here as a reference.

According to this invention, the manufacturing method of the glass substrate for flat panel glass which can prevent Ag colloid coloration, and the flat substrate glass glass substrate obtained by the said manufacturing method can be provided, maintaining favorable scratch resistance.

Furthermore, according to the present invention, Ag colloidal color can be prevented while maintaining good scratch resistance not only in PDP but also in FED, SED and the like.

Claims (17)

It is a manufacturing method of the glass substrate for flat panel glass which manufactures the glass substrate for flat panel glass by the float method, A molding step of molding the molten glass onto a glass substrate on molten tin, and a slow cooling step of slowly cooling the glass substrate molded by the molding step, A first supply step of spraying an inorganic substance containing an alkali metal on a surface of the glass substrate in contact with the molten tin and a surface of the glass substrate in contact with the molten tin after the first supply process. the method of the glass substrate for a flat panel glass having a second supply step of spraying the SO ₂ gas. It is a manufacturing method of the glass substrate for flat panel glass which manufactures the glass substrate for flat panel glass by the float method, A molding step of molding the molten glass onto a glass substrate on molten tin, and a slow cooling step of slowly cooling the glass substrate molded by the molding step, A first supply step of spraying an inorganic substance containing an alkali metal on a surface of the glass substrate that is not in contact with the molten tin, and a surface of the side that is in contact with the molten tin of the glass substrate after the first supply process a method for producing the glass substrate for a flat panel glass having a second supply step of spraying the SO ₂ gas. The manufacturing method of the glass substrate for flat panel glass of Claim 1 or 2 in which the said 1st supply process is performed between the said molding process and the said slow cooling process. The manufacturing method of the glass substrate for flat panel glass of Claim 1 or 2 in which the said 1st supply process is performed at the temperature of the glass transition point ± 100 degreeC of the said glass substrate. The manufacturing method of the glass substrate for flat panel glass of Claim 1 or 2 in which the said 1st supply process is performed at 550-750 degreeC. The manufacturing method of the glass substrate for flat panel glass of Claim 1 or 2 in which the said 2nd supply process is performed between the said molding process and the said slow cooling process. The manufacturing method of the glass substrate for flat panel glass of Claim 1 or 2 in which the said 2nd supply process is performed at the temperature of the glass transition point ± 100 degreeC of the said glass substrate. The manufacturing method of the glass substrate for flat panel glass of Claim 1 or 2 in which the said 2nd supply process is performed at 550-750 degreeC. It is a manufacturing method of the glass substrate for flat panel glass which manufactures the glass substrate for flat panel glass by the float method, A molding step of molding the molten glass onto the glass substrate on the molten tin; A first supply step of spraying an inorganic substance containing an alkali metal on a surface of the glass substrate in contact with the molten tin at 550 to 750 ° C., and the glass substrate at 550 to 750 ° C. after the first supply step. method of producing a glass substrate for a flat panel glass and a second supply step of spraying the SO ₂ gas to the surface of the side contacting the molten tin. It is a manufacturing method of the glass substrate for flat panel glass which manufactures the glass substrate for flat panel glass by the float method, A molding step of molding the molten glass onto the glass substrate on the molten tin; A first supply step of spraying an inorganic substance containing an alkali metal on a surface of the glass substrate at a side not in contact with the molten tin at 550 to 750 ° C., and the glass substrate at 550 to 750 ° C. after the first supply step in the production process of the glass substrate for a flat panel glass having a second supply step of spraying the SO ₂ gas to the surface of the side contacting the molten tin. The manufacturing method of the glass substrate for flat panel glass of any one of Claims 1, 2, 9, and 10 in which the said inorganic material containing an alkali metal contains sodium and boron. The method for producing a glass substrate for flat panel glass according to claim 11, wherein the inorganic substance containing the alkali metal is sodium tetraborate. The glass substrate for flat panel glass manufactured by the manufacturing method of Claim 11. It is a glass substrate for flat panel glass manufactured by the manufacturing method of Claim 11, The glass substrate is expressed as a percentage of mass on an oxide basis, SiO ₂ : 45-70%, Al ₂ O ₃ : 0-20%, CaO: 0-20%, ZrO ₂ : 0-13%, Total amount of alkaline earth metal oxide components: 5 to 40%, Total amount of alkali metal oxide component: 5 to 30% &Lt; / RTI &gt; The average boron concentration on the surface of the glass substrate on the side in contact with the molten tin and / or the surface of the glass substrate on the side not in contact with the molten tin is 2 to 6 atomic% (wherein the average boron concentration is X-ray The glass substrate for flat panel glass whose diffusion depth of boron into the inside of the said glass substrate is 20-80 nm. The glass substrate for flat panel glass of Claim 14 whose average H atom concentration from the surface of the side of the said glass substrate which does not contact the said molten tin to a depth of 0.1 micrometer is 2.5 mol% or less. It is a glass substrate for flat panel glass manufactured by the manufacturing method of Claim 11, The glass substrate is expressed as a percentage of mass on an oxide basis, SiO ₂ : 45-70%, Al ₂ O ₃ : 0-20%, CaO: 0-20%, ZrO ₂ : 0-13%, Total amount of alkaline earth metal oxide components: 5 to 40%, Total amount of alkali metal oxide component: 5 to 30% &Lt; / RTI &gt; The glass substrate for flat panel glass whose average H atom concentration from the surface of the side of the said glass substrate which does not contact the said molten tin to 0.1 micrometer depth is 2.5 mol% or less. In terms of mass percentages in terms of oxides, SiO ₂ : 45-70%, Al ₂ O ₃ : 0-20%, CaO: 0-20%, ZrO ₂ : 0-13%, Total amount of alkaline earth metal oxide components: 5 to 40%, Total amount of alkali metal oxide component: 5 to 30% &Lt; / RTI &gt; The average boron concentration of at least one surface is 2 to 6 atomic% (wherein the average boron concentration is obtained as an average value when five points are randomly measured by X-ray photoelectron spectroscopy), and the diffusion depth of boron from the surface to the inside is Glass substrate for flat panel glass which is 20-80 nm.

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