JPWO2014112415A1 - Manufacturing method of glass substrate with laminated film - Google Patents

Abstract

A CVD method using a glass manufacturing apparatus comprising a melting furnace for melting glass raw materials, a float bath for floating glass on a molten metal to form a glass ribbon, and a slow cooling furnace for gradually cooling the glass ribbon A method for producing a laminated film-attached glass substrate by forming a laminated film on the glass ribbon with a plurality of injectors provided in the annealing furnace, and cutting the glass ribbon, wherein the laminated film comprises two or more layers The glass substrate has a strain temperature Ts (° C.) of 550 ° C. or higher, and when the dislocation temperature of the glass substrate is Tg (° C.), the laminated film is formed with Tg or lower, A glass substrate with a laminated film, wherein a temperature drop K1 per unit length of the glass ribbon in a temperature region for forming all the layers of the film is 0 ° C./m<K1<10° C./m The method of production.

Description

  The present invention relates to a method for manufacturing a glass substrate with a laminated film, and more particularly to a method for producing a glass substrate with a laminated film, which forms a laminated film on a glass ribbon in a slow cooling furnace by an on-line CVD (Chemical Vapor Deposition) method.

  As a method for forming a film on a glass ribbon by an on-line CVD method, for example, methods described in Patent Documents 1 to 3 are known.

  Patent Document 1 discloses that an oxide containing silicon and oxygen is formed on a glass ribbon in a float bath by a CVD method. In this case, it is disclosed that an unsaturated hydrocarbon compound and carbon dioxide are used as an oxygen source in order to prevent oxidation of molten metal in the float bath by oxygen gas.

  Patent Document 2 discloses a method of sequentially forming a silicon dioxide film and a tin oxide film on a glass ribbon at a coating station (injector) disposed in a float bath and a coating station disposed in a slow cooling furnace.

  Patent Document 3 discloses a method of forming a film on a glass ribbon by providing a nozzle (injector) in a region between the float bath outlet and the annealing furnace inlet.

  Patent Document 4 discloses a method of forming a conductive film made of fluorine-doped tin oxide or antimony-doped tin oxide on a glass substrate having a strain point of 525 ° C. or higher.

JP-A-1-201046 JP-A-3-33036 Japanese Patent Publication No. 4-35558 JP 2010-28068 A

  In the float bath, the periphery of the molten metal is usually a non-oxidizing atmosphere to prevent oxidation of the molten metal. Further, the glass ribbon is in a soft state in the float bath, and when the film is formed on the soft glass ribbon in the float bath by the CVD method, the glass ribbon is not easily warped or cracked due to a temperature difference.

  Patent Document 1 discloses that an unsaturated hydrocarbon compound and carbon dioxide are used as an oxygen gas source for preventing oxidation of molten metal in a float bath. This is because oxygen gas cannot be used when forming an oxide film in a non-oxidizing atmosphere, and a reaction gas containing oxygen molecules needs to be used. However, when an oxide containing silicon and oxygen is formed by this method, hydrocarbon or carbon dioxide (C) derived from carbon dioxide is mixed into the oxide film. As a result, the absorption of the film is increased, and the film has a reduced transmittance as compared with the film not containing carbon.

  For this reason, there is a problem that the film quality deteriorates when an oxide film is formed in the float bath by the CVD method, and film formation outside the float bath is desired.

  In Patent Document 2, when a coating station is provided in a slow cooling furnace, a problem arises because the temperature conditions for film formation are different from the temperature conditions for slow cooling of the glass ribbon, and a multilayer coating is formed. Points out that the problem is more complicated. For this reason, Patent Document 2 recommends that the premixed oxygen and the coating precursor are brought into contact with the glass ribbon in the float bath. However, this method requires a seal to seal the oxygen gas and complicates the apparatus. Also, when a coating station is provided in the slow cooling furnace and a metal oxide film is to be formed on the glass ribbon, the heat exchange between the glass ribbon and the injector causes a rapid heat removal from the glass ribbon compared to the case without the coating station. May occur, and the glass ribbon may be deformed or scratches and cracks may occur. In particular, the greater the number of coating stations, the greater the risk that scratches and cracks will occur, and the warped glass ribbon may come into contact with the coating stations and cause scratches and cracks with the glass.

  For this reason, Patent Document 2 discloses that when one or more coating stations are provided in a slow cooling furnace when forming a multilayer coating, there is a problem that different temperature controls must be established. On the other hand, there is no specific disclosure of an appropriate temperature management method in the case where a plurality of coating stations are arranged in a slow cooling furnace.

  Patent Document 3 discloses that a nozzle (injector) is provided in a region between the float bath outlet and the annealing furnace inlet so as to cover the entire width of the glass. However, even if the conventional float manufacturing apparatus is used as it is, there is not sufficient space for disposing the nozzle between the float bath and the slow cooling furnace. In addition, the temperature of the glass ribbon is not controlled in the space between the float bath and the slow cooling furnace, and if a film is formed in the space between the float bath and the slow cooling furnace, the glass ribbon is rapidly changed due to heat exchange between the nozzle and the glass ribbon. There is a problem of heat removal.

  In addition, Patent Document 4 discloses that a conductive film is formed by an off-line CVD method, but there is a description that the on-line CVD method forms a film using the heat in a plate glass production line. However, no specific film forming method is disclosed.

  The present invention has been made paying attention to the above-mentioned problems. In the on-line CVD method, the glass ribbon having a high strain point of 550 ° C. or higher is appropriately controlled and provided in the slow cooling furnace. Provided is a method for producing a laminated film-attached glass substrate, wherein a laminated film is formed on a glass ribbon using a plurality of injectors.

In the present invention, a glass manufacturing apparatus including a melting furnace for melting a glass raw material, a float bath for floating a molten glass on a molten metal to form a glass ribbon, and a slow cooling furnace for gradually cooling the glass ribbon is used. A method for producing a glass substrate with a laminated film, wherein a laminated film is formed on the glass ribbon with a plurality of injectors provided in the slow cooling furnace by a CVD method, and the glass ribbon is cut.
The laminated film is composed of two or more layers,
The glass substrate has a strain temperature Ts (° C.) of 550 ° C. or higher,
When the transition temperature of the glass substrate is Tg (° C.), the laminated film is formed with Tg or less,
A glass substrate with a laminated film, wherein a temperature drop K1 per unit length of the glass ribbon in a temperature region for forming all the layers of the laminated film is 0 ° C./m<K1<10° C./m A manufacturing method is provided.

Here, in one embodiment of the method according to the present invention, the glass substrate, the linear expansion coefficient at 50 ° C. to 350 ° C. may be a ^{50 × 10 -7 / K~105 × 10} -7 / K. This is because the coefficient of thermal expansion is smaller than that of general glass such as soda lime glass, so that deformation is reduced when the same temperature change occurs, and the glass ribbon is less likely to warp or wave.

  In one embodiment of the manufacturing method according to the present invention, the glass substrate may have a Young's modulus of 75 GPa or more. This is because the Young's modulus is higher than that of general glass such as soda lime glass, so that deformation is reduced when the same stress occurs, and the glass ribbon is less likely to warp or wave.

  In one embodiment of the production method according to the present invention, the glass substrate has a temperature satisfying log η = 2 of more than 1500 ° C. and a temperature satisfying log η = 4 of 1100 when the viscosity is η (dPa · s). It may be ˜1260 ° C.

Moreover, in one aspect of the production method according to the present invention, the glass substrate is expressed in mass% based on oxide,
SiO ₂ 55~72,
Al ₂ O ₃ 5~18,
MgO 2-8,
CaO 0-8,
SrO 0-8,
BaO 0-10,
MgO + CaO + SrO + BaO 3.5-27,
Na ₂ O 0~15,
K ₂ O 0-12,
ZrO ₂ 0-5,
TiO ₂ 0-5,
Including
B ₂ O ₃ may have a substantially free composition of.

In this case, in particular, the glass substrate is expressed in mass% based on oxide,
ZrO ₂ 0.5-5
May be contained.

Further, the glass substrate is expressed in mass% based on oxide,
Na ₂ O ₊ K ₂ O 1~19
May be contained.

Further, the glass substrate is expressed in mass% based on oxide,
MgO + CaO 5-15
May be contained.

Further, the glass substrate is expressed in mass% based on oxide,
SiO ₂ + _{Al 2 O} 3 64~82
May be contained.

Further, the glass substrate is expressed in mass% based on oxide,
Fe ₂ O ₃ 0.005~0.1
May be contained.

  In one embodiment of the manufacturing method according to the present invention, at least two layers of the laminated film may be formed at a temperature of 510 ° C. or higher.

  In one embodiment of the manufacturing method according to the present invention, at least two layers of the laminated film may be formed at a temperature equal to or higher than Ts.

  In one embodiment of the manufacturing method according to the present invention, at least one layer may be formed at a temperature lower than Ts.

  In one aspect of the production method according to the present invention, the temperature drop per unit length in the temperature range from 510 ° C. to the outlet temperature of the slow cooling furnace is the unit length of the glass ribbon in the temperature range from Tg to 510 ° C. It may be larger than the hit temperature drop.

  Moreover, in the one aspect | mode of the manufacturing method by this invention, the heater may be provided between the injectors adjacent along the conveyance direction of the said glass ribbon.

Further, in one aspect of the manufacturing method according to the present invention, when the number of the plurality of injectors provided in the slow cooling furnace is N _INJ , the center-to-center distance T _INJ between the injectors adjacent in the transport direction is 1. It may be 0m ≦ T _INJ ≦ 25 / N _INJ m.

  Moreover, in one aspect of the production method according to the present invention, the distance between the lower surface of the injector and the glass ribbon may be 30 mm or less.

  According to the method for manufacturing a glass substrate with a laminated film of the present invention, in an on-line CVD method, appropriate temperature management is performed on a glass ribbon having a strain point of 550 ° C. or higher, and a plurality of injectors provided in a slow cooling furnace are provided. The manufacturing method of the glass substrate with a laminated film which uses and forms a laminated film on a glass ribbon is provided.

It is the schematic of the glass manufacturing apparatus by one Embodiment of this invention. It is sectional drawing of the injector by one Embodiment of this invention. It is sectional drawing of one Embodiment of the transparent conductive substrate for solar cells manufactured with the manufacturing method of the glass substrate with a laminated film of this invention. It is a graph explaining temperature control of the glass ribbon in the slow cooling furnace by one Embodiment of this invention.

  First, with reference to FIG. 1, one Embodiment of the glass manufacturing apparatus used for the manufacturing method of the glass substrate with a laminated film of this invention is described. In the following description, the term “film formation” may include the formation of at least one layer of a laminated film.

  As shown in FIG. 1, a glass manufacturing apparatus 50 includes a melting furnace 51 that melts a glass raw material, a float bath 52 that floats the molten glass on molten tin to form a flat glass ribbon, a lift-out After the glass ribbon is pulled out from the float bath 52 by the roll 53, the slow cooling furnace 54 that gradually cools the glass ribbon by gradually lowering the temperature of the glass ribbon is provided.

  The slow cooling furnace 54 slowly cools the glass ribbon transported by the transport roller 55 to a temperature range close to room temperature by supplying a heat amount whose output is controlled to a required position in the furnace by a combustion gas or an electric heater, for example. Thereby, it has the effect | action which eliminates the residual stress which exists in a glass ribbon, and suppresses a curvature and a crack generating in a glass ribbon. A plurality of injectors 60 are provided in the slow cooling furnace 54, and a laminated film is formed on the glass ribbon by a CVD method.

  The injector 60 includes six injectors 60a to 60f, and forms a laminated film on the glass ribbon to be conveyed. An electric heater 56 is provided between the injectors. In addition, the number of the injectors 60 is not limited to this, Preferably it exists in the range of 2-9 pieces, and an electric heater can also be increased / decreased as needed. These electric heaters prevent the temperature of the glass ribbon from excessively decreasing from the inlet to the outlet in the slow cooling furnace. On the other hand, the heater installed between the injectors can heat the glass ribbon between the injectors, but since it does not heat the glass ribbon on the lower surface of the injector, it is cooled from the inlet to the outlet of the injector by the installation of this heater There is no effect on the temperature change of the glass ribbon.

  The injector 60 (60a-60f) is arrange | positioned above the glass ribbon 70 on the opposite side to the conveyance roller 55 on both sides of the glass ribbon 70, as shown in FIG. Each injector is provided with a slit-like air outlet 61 that is elongated in a direction perpendicular to the glass ribbon conveyance direction at a substantially central portion of the lower surface 65, and exhaust that extends in parallel with the air outlet 61 on both sides in the front-rear direction of the air outlet 61. A mouth 62 is provided.

  In the blower outlet 61, the first orifice 61a located in the center and the first orifice 61a are positioned in the front-rear direction so as to incline the flow path from the source gas supply source toward the first orifice 61a. The configured second and third orifices 61b and 61c are opened. The widths of these air outlets 61 and exhaust ports 62 are narrower than the width of the glass ribbon 70, and are set to be equal to or larger than the product width of the glass ribbon excluding the ears to be separated and recovered. Reference numerals 66a and 66b denote cooling ducts, which circulate a cooling medium such as cooling gas or oil, and maintain the injector 60 at an optimum temperature, for example, 100 ° C. to 220 ° C. (measured on the lower surface of the injector). The lower surface of the injector 60 is a surface in contact with the raw material gas. If the temperature is too high, the raw material gas in contact with the lower surface of the injector 60 reacts with heat and adheres to form an unnecessary film. For this reason, the upper limit is preferably 250 ° C. or less. On the other hand, if the temperature is too low, the amount of heat exchange with the glass ribbon increases, causing a rapid temperature drop of the glass ribbon. For this reason, the lower limit is desirably 100 ° C. or higher.

  The injector 60 is disposed above the glass ribbon 70 with an interval of 3 mm to 30 mm. Therefore, the lower surface 65 of the injector 60 is opposed to the glass ribbon 70 conveyed into the slow cooling furnace 54 through a gap of 3 mm to 30 mm. The smaller the gap, the more advantageous the film thickness, film quality, and film formation speed during film formation. However, when the gap fluctuates due to warping or vibration of the glass ribbon, the influence on the film thickness and film quality increases. In addition, when the gap is large, the efficiency of the raw material during film formation is reduced. Considering the film thickness, film quality, and film forming speed, the gap is preferably 4 to 12 mm, more preferably 5 to 10 mm.

  From the first orifice 61a, a gas containing the main raw material of the compound forming the oxide film is blown out. Further, a reactive gas (a gas that becomes an oxygen source) for forming the oxide film is blown out from the second and third orifices 61b and 61c. The exhaust port 62 exhausts excess gas after the CVD reaction.

  The composition of the glass ribbon is not particularly limited as long as it can finally obtain a high strain point glass substrate.

  In the present application, “high strain point glass (substrate)” means glass (substrate) having a strain temperature Ts of 550 ° C. or higher.

  The composition of the glass ribbon may be, for example, a composition that finally produces borosilicate glass or alkali-free glass.

  Hereinafter, an example of the composition of the glass ribbon will be described.

The glass ribbon (or the finally produced glass substrate, the same applies hereinafter), for example, in terms of mass% based on oxide,
SiO ₂ 55~72,
Al ₂ O ₃ 5~18,
MgO 2-8,
CaO 0-8,
SrO 0-8,
BaO 0-10,
MgO + CaO + SrO + BaO 3.5-27,
Na ₂ O 0~15,
K ₂ O 0-12,
ZrO ₂ 0-5,
TiO ₂ 0-5,
Including
B ₂ O ₃ may not be substantially contained.

Here, SiO ₂ (silicon oxide) is a main component that forms a skeleton of glass. When the SiO ₂ content is less than 55% by mass, the durability of the glass is lowered.

The content of SiO ₂ is preferably 57 to 72% by mass.

Al ₂ O ₃ (aluminum oxide) is a component that improves the durability of the glass, so it is contained in an amount of 5% by mass or more. However, if it exceeds 18% by mass, melting of the glass becomes extremely difficult.

The content of Al ₂ O ₃ is preferably 6 to 15% by mass, and more preferably 7.5 to 14% by mass.

Further, the total amount of SiO ₂ and Al ₂ O ₃ (SiO ₂ + Al ₂ O ₃ ) is preferably 64% by mass or more in order to increase the chemical durability of the glass, and the glass melt can be stabilized. In order to ensure that the high-temperature viscosity does not become too high, it is preferably 82% by mass or less.

  Alkaline earth metal oxides, that is, MgO (magnesium oxide), CaO (calcium oxide), SrO (strontium oxide) and BaO (barium oxide) improve the durability of the glass and the devitrification temperature during molding. Used to adjust viscosity.

  When MgO exceeds 8 mass%, devitrification temperature will rise. When CaO exceeds 8 mass%, devitrification temperature will rise. When SrO exceeds 8% by mass, the devitrification temperature rises. When BaO exceeds 10 mass%, devitrification temperature will rise.

  Further, when the total amount (RO) of the oxide of the alkaline earth metal is less than 3.5% by mass, the durability of the glass is lowered, and when it exceeds 27% by mass, the devitrification temperature is increased.

Further, when the total amount (RO) of the oxide of the alkaline earth metal is 3.5 to 27% by mass, the Cl concentration in the tin oxide film formed on the glass substrate becomes low, and the tin oxide The mobility of the film is improved. Here, the generation source of Cl in the tin oxide film is a tin chloride compound (SnCl ₄ , SnHCl ₃ , SnH ₂ Cl ₂ , SnH) used as a Sn raw material when forming the tin oxide film by the atmospheric pressure CVD method. ₃ and inorganic tin compounds such as Cl, a monobutyltin trichloride, tin chloride compounds of organic, such as dibutyltin dichloride).

  The reason why the Cl concentration in the tin oxide film formed on the glass substrate is low when RO is in the above range is considered as follows.

  When forming a tin oxide film on a glass substrate using atmospheric pressure CVD, if the glass RO constituting the glass substrate has a composition in the above range, the number of nucleation sites on the glass substrate increases, and It is considered that the crystallinity of the tin oxide film formed is improved. As a result, it is considered that the Cl concentration in the tin oxide film decreases.

  On the other hand, when the RO of the glass constituting the glass substrate is outside the above range, the nucleation sites on the glass substrate are reduced, and the crystallinity of the tin oxide film to be formed is considered to be lowered. As a result, it is considered that the Cl concentration in the tin oxide film increases and the mobility of the tin oxide film decreases.

  It is preferable that RO of the glass which comprises a glass substrate is 5-27 mass%.

  In view of the action of reducing the Cl concentration in the tin oxide film formed on the glass substrate, the influence of MgO and CaO is large among the alkaline earth metal oxides. For this reason, it is preferable that it is 2-16 mass%, and, as for the total amount (MgO + CaO) of MgO and CaO, it is more preferable that it is 5-15 mass%.

Na ₂ O (sodium oxide) and K ₂ O (potassium oxide) are used as glass melting accelerators. However, if Na ₂ O exceeds 15% by mass, the durability of the glass is lowered. Moreover, since K ₂ O is more expensive than Na ₂ O, it is not preferable to exceed 12% by mass.

In order not to lower the durability of the glass, the total amount of Na ₂ O and K ₂ O (Na ₂ O + K ₂ O) is preferably 19% by mass or less, and acts as a glass dissolution accelerator. Therefore, it is preferable that Na ₂ O + K ₂ O is 1% by mass or more.

ZrO ₂ (zirconium oxide), like the alkaline earth metal oxide, has the effect of reducing the Cl concentration in the tin oxide film formed on the glass substrate, so it can be contained up to 5% by mass. it can. If the content of ZrO ₂ exceeds 5% by mass, the nucleation sites on the glass substrate are decreased, and the crystallinity of the tin oxide film formed is considered to be decreased. As a result, it is considered that the Cl concentration in the tin oxide film increases and the mobility of the tin oxide film decreases.

The content of ZrO ₂ is more preferably 0.5 to 5 mass%.

Since TiO ₂ (titanium oxide) has an effect of lowering the high temperature viscosity of the glass, it can be contained up to 5% by mass. When the content of TiO ₂ exceeds 5 mass%, the glass tends to be devitrified.

Since inconvenience during molding due to volatilization of B ₂ O ₃ is generated, the glass constituting the glass substrate is a composition that is substantially free.

The glass constituting the glass substrate can contain 0.005 to 0.1% by mass of Fe ₂ O ₃ (iron oxide).

When the content of Fe ₂ O ₃ is less than 0.005% by mass, the heat ray transmittance of the glass becomes high. Therefore, during glass production, the temperature distribution in the melting tank is difficult to occur, and convection of the molten glass is difficult to occur. Therefore, it is difficult to obtain a homogeneous glass. When the content of Fe ₂ O ₃ is more than 0.1% by mass, the heat ray transmittance of the glass is lowered, so that the battery efficiency of the solar cell produced using the substrate with a transparent conductive film is lowered, which is not preferable. The content of Fe ₂ O ₃ is more preferably from 0.007 to 0.08 wt%.

  A glass substrate made of glass having the above composition has a strain point of 550 ° C. or higher.

  By using glass having such a high strain point as the glass ribbon, the film forming temperature can be increased when forming a tin oxide film, which is a transparent conductive film, on the glass substrate by atmospheric pressure CVD. High-speed film formation is possible.

  The strain point of the glass substrate is preferably 565 ° C. or higher.

  In the present invention, the strain point is a strain point (strain point) measured according to “JIS R3103-2”.

Further, the glass substrate produced from a glass ribbon of the composition has an average thermal expansion coefficient at 50 to 300 ° C. is ^{50 × 10 -7 ~105 × 10 -7} / ℃.

The average thermal expansion coefficient of the glass substrate at 50 to 300 ° C. is preferably 54 × 10 ^{−7 to} 100 × 10 ⁻⁷ / ° C.

  The glass substrate composed of the glass having the above composition has a temperature satisfying log η = 2 of over 1500 ° C. and a temperature satisfying log η = 4 of 1100 to 1260 when the viscosity is η (dPa · s). ° C. Here, the temperature satisfying log η = 2 is a temperature serving as an index of solubility, and the temperature satisfying log η = 4 is a temperature serving as an index of formability of glass. If the temperature satisfying log η = 4 is in the above range, it is suitable for float forming.

  The thickness of the glass ribbon can be selected as appropriate, and the glass thickness is preferably 0.1 to 6.0 mm. In thin glass, the temperature difference between the front and back is less likely to occur, so there is little warpage on the injector side, but because the glass itself is light, the glass that has warped once on the injector side does not return warp due to its own weight. Thick glass tends to cause a temperature difference between the front and back, but because of its own weight, it works to reduce warpage. For this reason, even if the glass thickness changes between 0.1 and 6.0 mm, the warpage amount itself does not change so much.

  In addition, one or more thin films may be formed on the surface of the glass ribbon in advance in the process prior to the slow cooling furnace within a range not impairing the effects of the present invention. For example, a base layer may be formed on the surface of the glass ribbon in a float bath.

  The type, configuration, and the like of the laminated film to be formed are not particularly limited and can be selected as appropriate. In the following description, an example of forming a transparent conductive film for a solar cell will be described. Examples of uses other than the transparent conductive film for solar cells include an antireflection film and a heat ray reflective film.

  FIG. 3 is a cross-sectional view of one embodiment of a transparent conductive substrate for a solar cell produced by the method for producing a glass substrate with a laminated film of the present invention. It is illustrated so that the incident light side of the transparent conductive substrate for solar cell is located on the lower side of FIG.

  As shown in FIG. 3, the transparent conductive substrate 10 for a solar cell includes a titanium oxide layer 14, a silicon oxide layer 16, and a first film as a laminated film 13 on the glass substrate 12 from the glass substrate 12 side. It has the tin oxide layer 18 and the 2nd tin oxide layer 20 in this order.

  The material of the glass substrate 12 is not particularly limited as long as it is a high strain point glass, and may be, for example, borosilicate glass or alkali-free glass.

  The thickness of the glass substrate 12 is preferably 0.1 to 6.0 mm. Within the above range, the balance between mechanical strength and translucency is excellent.

  In FIG. 3, a titanium oxide layer 14 is formed on the glass substrate 12. In the present invention, the aspect having the titanium oxide layer 14 between the glass substrate 12 and the silicon oxide layer 16 is the glass substrate 12 and tin oxide generated due to the difference in refractive index between the glass substrate 12 and the tin oxide layers 18 and 20. Since reflection at the interface with the layers 18 and 20 can be suppressed, this is one of preferred embodiments.

  In order to form the laminated film 13 of the transparent conductive substrate 10 for solar cells in the slow cooling furnace 54 of the glass manufacturing apparatus 50 shown in FIG. 1 by the CVD method, for example, the titanium oxide is formed on the glass ribbon by the first injector 60a. The layer 14 is formed, the silicon oxide layer 16 is formed by the second injector 60b, the first tin oxide layer 18 is formed by the third injector 60c, and the second is formed by the fourth to sixth injectors 60d to 60f. The tin oxide layer 20 is formed.

  In this case, vaporized tetraisopropoxy titanium is blown from the first orifice 61a and nitrogen gas is blown from the second and third orifices 61b and 61c at the outlet 61 of the first injector 60a. Thereby, tetraisopropoxy titanium undergoes a thermal decomposition reaction on the glass ribbon, and a titanium oxide layer 14 is formed on the surface of the glass ribbon being conveyed.

  At the outlet 61 of the second injector 60b, silane gas is blown from the first orifice 61a, and oxygen gas is blown from the second and third orifices 61b and 61c. Thereby, silane gas and oxygen gas are mixed and reacted on the titanium oxide 14 layer of the glass ribbon, and the silicon oxide layer 16 is formed on the surface of the titanium oxide layer 14 of the glass ribbon being conveyed.

  At the air outlet 61 of the third injector 60c, tin tetrachloride is blown from the first orifice 61a, and water vapor is blown from the second and third orifices 61b and 61c. Thereby, tin tetrachloride and water are mixed and reacted on the silicon oxide layer 16 of the glass ribbon, and the surface of the silicon oxide layer 16 of the glass ribbon being conveyed is not doped with fluorine. A tin oxide layer 18 is formed.

  At the outlets 61 of the fourth to sixth injectors 60d to 60f, tin tetrachloride is blown from the first orifice 61a, and hydrogen fluoride vaporized from the second and third orifices 61b and 61c is vaporized. Is sprayed. Thereby, tin tetrachloride, water, and hydrogen fluoride are mixed and reacted on the first tin oxide layer 18 of the glass ribbon, and the surface of the first tin oxide layer 18 of the glass ribbon in a state of being conveyed. A second tin oxide layer 20 doped with fluorine is formed.

  The glass ribbon on which the second tin oxide layer 20 is formed is discharged from the slow cooling furnace 54 while being transported, cooled to near room temperature, cut into a desired size, and carried out as the transparent conductive substrate 10 for solar cells. The

  As described above, it is preferable to form an oxide material such as titanium oxide, silicon oxide, or tin oxide in the film formation in the slow cooling furnace. This is because the atmosphere in the slow cooling furnace is air, and it is easy to supply oxygen molecules such as oxygen gas when forming oxides.

  Here, the temperature control of the glass ribbon during film formation will be described with reference to FIG.

  The surface temperature Tin of the glass ribbon when passing through the inlet of the slow cooling furnace 54 is defined as Tin, and the surface temperature of the glass ribbon when passing through the outlet of the slow cooling furnace 54 is defined as Tout. Moreover, let the glass transition temperature of a glass ribbon be Tg, and let it be glass distortion temperature Ts.

  In this embodiment, the surface temperature of the glass ribbon to be formed is Tg or less. If the surface temperature of the glass ribbon is higher than Tg, the glass ribbon is liable to cause “not-engraved marks” or planar defects. In addition, in the temperature region where the surface temperature of the glass ribbon is higher than Tg, the temperature is too high, and the vapor phase growth of the film forming raw material is increased, and the film forming rate is decreased, and film defects due to powder generation are likely to occur. Become.

  The lower limit of the surface temperature of the glass ribbon to be formed is not particularly limited as long as the temperature is higher than Tout, but the surface temperature of the glass ribbon is preferably 510 ° C. or higher. When the surface temperature of the glass ribbon is lower than 510 ° C., the deposition rate of the laminated film by the CVD method is remarkably reduced. Therefore, it is preferable to complete all the film formation when the glass ribbon has a surface temperature of 510 ° C. or higher.

  In this embodiment, at least two layers may be formed at a temperature equal to or higher than Ts. If it is Ts or more, the strain introduced between the laminated film and the glass ribbon can be relaxed.

  Here, in this embodiment, at least one layer of the laminated film may be formed at a temperature equal to or lower than Ts.

  In the glass ribbon used when producing a glass having a general composition other than the high strain point glass, the strain temperature is approximately 510 ° C. or less (for example, 510 ° C. for soda lime glass). Therefore, when the film is formed in a state where the temperature of the glass ribbon is equal to or lower than the strain temperature Ts, the film formation speed of the laminated film is remarkably reduced, and it becomes difficult to perform film formation at a realistic film formation speed.

  On the other hand, the glass ribbon used in this embodiment is a glass ribbon for high strain point glass, and has a strain temperature Ts of 550 ° C. or higher. Therefore, even if the temperature of the glass ribbon is equal to or lower than the strain temperature Ts, the advantage is obtained that the layer can be formed at an appropriate film forming rate if the temperature of the glass ribbon is 510 ° C. or higher. .

  From the above, the laminated film 13 composed of the titanium oxide layer 14, the silicon oxide layer 16, the first tin oxide layer 18, and the second tin oxide layer 20 is formed with Tg or less. Preferably, the laminated film 13 is formed within a temperature range of Tg or lower and 510 ° C. or higher.

  Since the injector 60 is maintained at a temperature lower than that of the glass ribbon, heat exchange is performed with the injector 60 during film formation, thereby lowering the temperature of the glass ribbon.

  For this reason, in the present invention, when “a temperature drop per unit length of the glass ribbon in the temperature region where all laminated films are formed” is K1 (hereinafter, also simply referred to as a temperature drop K1), K1 is 0. C / m <K1 <10 ° C./m. K1 is preferably set to 1 ° C./m≦K1≦5° C./m, more preferably 2 ° C./m≦K1≦3° C./m.

  Note that the temperature drop K1 is the “temperature difference between the glass ribbon temperature at the inlet of the first injector and the glass ribbon temperature at the outlet of the last injector when forming the laminated film” in the temperature region where the laminated film is formed. Divided by the difference in the distance between the inlet position of the first injector and the outlet position of the last injector. If the temperature drop K1 is 10 ° C./m or more, the glass ribbon may be greatly deformed, and the glass ribbon may be damaged or cracked due to contact between the injector and the glass ribbon. If the temperature drop K1 is 0 ° C./m, the film is formed. In some cases, the glass ribbon is not gradually cooled in the slow cooling furnace 54, and the slow cooling furnace 54 is lengthened because the glass ribbon is gradually cooled after film formation.

  The glass ribbon whose temperature has been lowered by the injector 60 may be heated by the electric heater 56 or the like provided between the injectors 60 adjacent to each other along the glass ribbon conveyance direction to moderate the temperature drop K1. The amount of heat removed by the injector 60 also depends on the area of the lower surface 65 of the injector 60 that faces the glass ribbon. Therefore, the area of the lower surface 65 may be reduced in advance in order to reduce the amount of heat removal.

  The temperature of the glass ribbon used for calculating the temperature drop K1 is the temperature of the upper surface (film formation side) of the glass ribbon. The temperature difference between the upper surface of the glass ribbon and the lower surface of the position during film formation is preferably within 10 ° C. By setting the temperature difference between the upper surface of the glass ribbon and the lower surface at that position to be within 10 ° C., the warp of the glass ribbon below the injector is further suppressed, and the contact between the injector and the glass ribbon is more reliably suppressed.

Here, it is desirable to make the total length of the slow cooling furnace as short as possible. More specifically, when the number of injectors provided in the slow cooling furnace is N _INJ , the center-to-center distance T _INJ between the injectors adjacent in the glass ribbon transport direction is 1.0 m ≦ T _INJ ≦ 25 / N _INJ m is preferable. The reason why the center-to-center distance T _INJ between the adjacent injectors is set to 1.0 m or more is that if the center-to-center distance T _INJ is shorter than 1.0 m, the adjacent injectors may be affected. In the above embodiment, since the number of injectors provided in the slow cooling furnace is six, the center-to-center distance T _INJ between the injectors is set to 1.0 m ≦ T _INJ ≦ 4.17 m. When the length of the injector in the conveying direction is L _INJ , the gap between adjacent injectors, in other words, the heater disposition possible length L _h is 1.0−L _INJ m ≦ L _h ≦ 4.17−L _INJ m.

  The gap between the lower surface 65 of the injector 60 and the glass ribbon needs to be stable at the time of film formation. However, if the glass ribbon is warped, the gap between the lower surface 65 of the injector 60 and the glass ribbon fluctuates. The film thickness and the film quality are likely to be uneven. In particular, when the film thickness is large (for example, 600 nm or more), the stress of the film is generated, so that the warp of the glass ribbon after the film formation tends to increase. For this reason, it is preferable to form all the layers in the temperature range from Tg to Ts, particularly when a thick film is formed.

  In addition, since the influence on the warpage of the glass is small in a temperature region lower than 510 ° C., after the formation of all the layers of the laminated film 13, the temperature is higher than the temperature drop of the glass ribbon in the temperature region where the laminated film 13 is formed. The glass ribbon can be cooled at a temperature lowering rate.

  Examples of the present invention will be described below.

  In the examples described below, the temperature was measured with a contact-type K-type thermocouple (sensor, manufactured by Anri Keiki Co., Ltd .: 213K-TC1-ASP).

<Example 1>
In this embodiment, when manufacturing the high strain point glass, as shown in FIG. 1, the electric heaters 56 are arranged between the six injectors 60 a to 60 f and each injector in the slow cooling furnace, and the first on the glass ribbon. The titanium oxide layer 14 is formed by the second injector 60a, the silicon oxide layer 16 is formed by the second injector 60b, the first tin oxide layer 18 is formed by the third injector 60c, and the fourth to sixth injectors are formed. The 2nd tin oxide layer 20 was formed by 60d-60f, and it cut | disconnected after that in the desired magnitude | size, and formed the transparent conductive film 10 for solar cells shown in FIG. The gas blown out from each injector 60a-60f is as described above. Six injectors were arranged at regular intervals of 2 m between the centers of the injectors. The flow rate P of the glass ribbon was 300 ton / day, and the area S of the lower surface of the injector was 0.36 m ² . In particular, since oxygen gas can be used when producing silicon oxide, the film has no deterioration in film quality and has a low absorption. The gap from the lower surface of the injector to the glass ribbon was 7 mm ± 1 mm.

As a glass ribbon, in terms of mass% based on oxide, SiO ₂ is 57.6, Al ₂ O ₃ is 7.0, SiO ₂ + Al ₂ O ₃ is 64.6, MgO is 2.0, and CaO is 5 0.0, SrO 7.0, BaO 8.0, RO (MgO + CaO + SrO + BaO) 22.0, MgO + CaO 7.0, Na ₂ O 4.1, K ₂ O 6.3, Na ₂ O + K ₂ A composition having O of 10.4 and ZrO ₂ of 3.0 was used.

  The temperature of the glass ribbon was measured before and after the injector. The distance between measurement points was 2 m. The temperature of the glass ribbon on the lower surface of the center of the injector was calculated. Since the decrease in the temperature of the glass ribbon is mainly due to radiation cooling to the injector, the average temperature before and after the injector was taken as the temperature of the glass ribbon on the lower surface of the center of the injector. Table 1 shows the temperature measurement position and the temperature of the glass ribbon at the center of the injector when the transparent conductive film was formed using six injectors.

徐冷炉の入口におけるガラスリボン温度を６２０℃、徐冷炉の出口におけるガラスリボン温度を２５０℃とし、ガラス転位温度Ｔｇが６２５℃、ガラス歪温度Ｔｓが５７０℃の高歪点ガラスにおいて、ＴｇからＴｇ−３５℃の温度領域、すなわち６２５℃から５９０℃の温度領域に３つのインジェクターを配置し、ＴｇからＴｇ−３５℃の温度領域で３層形成した。また、５９０℃から５５０℃の温度領域に３つのインジェクターを配置し、Ｔｇ−３５℃からＴｓ−１０℃の温度領域で３層形成した。

In a high strain point glass where the glass ribbon temperature at the inlet of the slow cooling furnace is 620 ° C., the glass ribbon temperature at the outlet of the slow cooling furnace is 250 ° C., the glass transition temperature Tg is 625 ° C., and the glass strain temperature Ts is 570 ° C., Tg to Tg−35 Three injectors were arranged in a temperature region of ℃, that is, a temperature region of 625 ° C. to 590 ° C., and three layers were formed in a temperature region of Tg to Tg−35 ° C. In addition, three injectors were arranged in a temperature range from 590 ° C to 550 ° C, and three layers were formed in a temperature range from Tg-35 ° C to Ts-10 ° C.

  At this time, by heating the glass ribbon with an electric heater, the temperature drop per unit length in the temperature range from Tg to Tg-35 ° C. is 5 ° C./m to 7 ° C./m, and the average is 6 ° C./m. Maintained. The temperature drop per unit length in the temperature range from Tg-35 ° C. to Ts was also 2 ° C./m to 3.5 ° C./m. The temperature drop K1 per unit length of the glass ribbon in the temperature region for forming all the laminated films was 4.3 ° C./m. At this time, the temperature of the glass ribbon cooled from the inlet Iin to the outlet Iout of each injector was 4 ° C to 14 ° C. From the glass strain temperature Ts to the outlet temperature of 250 ° C., the glass ribbon was gradually cooled at a temperature drop of 14 ° C./m to 18 ° C./m and an average of 16 ° C./m per unit length.

  During the formation of the laminated film by the CVD method, no cracking or warping of the glass ribbon was observed. After cooling, the glass ribbon was cut into a desired size to obtain a substrate with a transparent conductive film for solar cells.

  When the warpage of the transparent conductive substrate for solar cell thus manufactured was measured, the warpage was 0.3 mm, which was within the allowable range (1 mm). Also, no scratches or cracks were generated. In addition, the measurement of the curvature is performed by measuring the distance from the sensor to the surface of the transparent conductive substrate for solar cells while horizontally supporting both ends of the transparent conductive substrate for solar cells having a product size (1100 mm × 1400 mm). The transparent conductive substrate for solar cells was turned over, the distance from the sensor to the back surface of the transparent conductive substrate for solar cells was measured, and the measurement was performed by eliminating the influence of deflection due to its own weight.

  As is apparent from Table 1, in each injector, the temperature of the glass ribbon cooled from the inlet to the outlet of the injector was 14 ° C. or less.

  From Table 1, find the temperature difference between the first injector inlet temperature and the last injector outlet temperature, and form the temperature range that forms all the layers divided by the difference of 10.5m in the distance between the first injector inlet position and the last injector outlet position Table 2 shows the temperature drop K1 per unit length.

表２より、全ての層を形成する温度領域の単位長さ当たりの降下温度Ｋ１は、５．０℃／ｍであった。

From Table 2, the temperature drop K1 per unit length of the temperature region forming all the layers was 5.0 ° C./m.

  As described above, according to the method for manufacturing a glass substrate of the present embodiment, when a laminated film is formed on a high strain point glass ribbon in a slow cooling furnace by an on-line CVD method, the laminated film is formed at a temperature of Tg or less. At the same time, by setting the temperature drop of the glass ribbon in the temperature region for forming all the layers of the laminated film to 0 ° C./m<K1<10° C./m, contact between the injector and the glass ribbon is avoided, It was possible to suppress the occurrence of scratches and cracks.

  The present invention is not limited to the embodiment described above, and can be implemented in various forms without departing from the gist of the present invention.

  For example, although an electric heater has been exemplified as the heater, any heating means can be used without being limited thereto.

  Moreover, this application claims the priority based on the Japan patent application 2013-005029 for which it applied on January 16, 2013, and uses all the content of the Japan application for this application by reference.

10 Transparent conductive substrate for solar cells (Glass substrate with laminated film)
13 Laminated Film 50 Glass Manufacturing Equipment 51 Melting Furnace 52 Float Bath 54 Slow Cooling Furnace 56 Electric Heater 60 Injector 70 Glass Ribbon

Claims (17)

A CVD method using a glass manufacturing apparatus comprising a melting furnace for melting glass raw materials, a float bath for floating glass on a molten metal to form a glass ribbon, and a slow cooling furnace for gradually cooling the glass ribbon A method for producing a laminated film-attached glass substrate by forming a laminated film on the glass ribbon with a plurality of injectors provided in the slow cooling furnace, and cutting the glass ribbon,
The laminated film is composed of two or more layers,
The glass substrate has a strain temperature Ts (° C.) of 550 ° C. or higher,
When the transition temperature of the glass substrate is Tg (° C.), the laminated film is formed with Tg or less,
A glass substrate with a laminated film, wherein a temperature drop K1 per unit length of the glass ribbon in a temperature region for forming all the layers of the laminated film is 0 ° C./m<K1<10° C./m Production method. The glass substrate manufacturing method according to claim 1, wherein the coefficient of linear expansion at 50 ° C. to 350 ° C. is ^{50 × 10 -7 / K~105 × 10} -7 / K.   The manufacturing method according to claim 1, wherein the glass substrate has a Young's modulus of 75 GPa or more.   2. The glass substrate has a temperature satisfying log η = 2 of more than 1500 ° C. and a temperature satisfying log η = 4 of 1100 to 1260 ° C. when the viscosity is η (dPa · s). The manufacturing method as described in any one of thru | or 3. The glass substrate is expressed by mass% based on oxide,
SiO ₂ 55~72,
Al ₂ O ₃ 5~18,
MgO 2-8,
CaO 0-8,
SrO 0-8,
BaO 0-10,
MgO + CaO + SrO + BaO 3.5-27,
Na ₂ O 0~15,
K ₂ O 0-12,
ZrO ₂ 0-5,
TiO ₂ 0-5,
Including
B ₂ O ₃ is not substantially contained, The manufacturing method as described in any one of the Claims 1 thru | or 4 characterized by the above-mentioned. The glass substrate is expressed by mass% based on oxide,
ZrO ₂ 0.5-5
The manufacturing method of Claim 5 characterized by the above-mentioned. The glass substrate is expressed by mass% based on oxide,
Na ₂ O ₊ K ₂ O 1~19
The manufacturing method of Claim 5 or 6 characterized by the above-mentioned. The glass substrate is expressed by mass% based on oxide,
MgO + CaO 5-15
The production method according to any one of claims 5 to 7, further comprising: The glass substrate is expressed by mass% based on oxide,
SiO ₂ + _{Al 2 O} 3 64~82
The production method according to claim 5, further comprising: The glass substrate is expressed by mass% based on oxide,
Fe ₂ O ₃ 0.005~0.1
The production method according to any one of claims 5 to 9, further comprising:   The manufacturing method according to claim 1, wherein at least two layers of the laminated film are formed at a temperature of 510 ° C. or higher.   The manufacturing method according to claim 1, wherein at least two layers of the laminated film are formed at a temperature equal to or higher than Ts.   The manufacturing method according to claim 1, wherein at least one layer is formed at a temperature lower than Ts.   A temperature drop per unit length in a temperature range from 510 ° C. to the outlet temperature of the annealing furnace is larger than a temperature drop per unit length of the glass ribbon in a temperature range from Tg to 510 ° C. The manufacturing method as described in any one of Claims 1 thru | or 13.   The manufacturing method according to any one of claims 1 to 14, wherein a heater is provided between injectors adjacent to each other in the conveyance direction of the glass ribbon. When the number of the plurality of injectors provided in the slow cooling furnace is N _INJ , the center-to-center distance T _INJ between the injectors adjacent in the transport direction is 1.0 m ≦ T _INJ ≦ 25 / N _INJ m The manufacturing method according to any one of claims 1 to 15, wherein:   The manufacturing method according to any one of claims 1 to 16, wherein a distance between the lower surface of the injector and the glass ribbon is 30 mm or less.

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