WO2011077153A2 - Procédé de dépôt - Google Patents

Procédé de dépôt Download PDF

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Publication number
WO2011077153A2
WO2011077153A2 PCT/GB2010/052189 GB2010052189W WO2011077153A2 WO 2011077153 A2 WO2011077153 A2 WO 2011077153A2 GB 2010052189 W GB2010052189 W GB 2010052189W WO 2011077153 A2 WO2011077153 A2 WO 2011077153A2
Authority
WO
WIPO (PCT)
Prior art keywords
coating
substrate
oxidant
fluid mixture
flame
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB2010/052189
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English (en)
Other versions
WO2011077153A3 (fr
Inventor
Kevin David Sanderson
Troy Darrell Manning
Allan Stuart Dale
Simon James Hurst
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pilkington Group Ltd
Original Assignee
Pilkington Group Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pilkington Group Ltd filed Critical Pilkington Group Ltd
Publication of WO2011077153A2 publication Critical patent/WO2011077153A2/fr
Publication of WO2011077153A3 publication Critical patent/WO2011077153A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
    • C23C16/453—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating passing the reaction gases through burners or torches, e.g. atmospheric pressure CVD

Definitions

  • This invention relates to processes for the deposition of an anti-reflection coating on a substrate and to coated substrates comprising an anti-reflection coating on at least one surface.
  • Reduced reflections are a desirable feature of many optical systems.
  • Anti reflection coatings increase transmission of incident light (by reducing reflection) and are a potentially useful feature of devices such as the covers for photovoltaic panels and photovoltaic cells.
  • the degree of anti reflection which is provided by a coating comprising a single layer of material on the surface of a substrate is often highest if porous coatings are deposited. However, the deposition of such porous coatings is not straightforward.
  • Sol gel type deposition processes have been proposed in which a silica sol is coated on to the surface of a substrate and heated at elevated temperature so as to drive off organic material resulting in the production of the anti reflective silica coating.
  • Processes of this type have been disclosed in EP 1429997, DE 10146687, EP1328483 and USP 6918957 and are in commercial use. However the process is time consuming and the cost of production is relatively high. Moreover the coatings produced may be insufficiently durable to resist secondary glass processing such as toughening and laminating processes without significant deterioration in their properties.
  • USPA 2006/003108 discloses a process for depositing a reflection reducing coating on to the surface of a glass substrate at 80°C in which a silicon containing precursor is decomposed with a flame and the substrate is introduced into the flame so as to apply the precursor to the substrate directly from the gas phase as an SiO x (OH) 4 _ x coating wherein 0 ⁇ x ⁇ 2.
  • the processes are used to coat glass panes which are passed repeatedly through the flame in order to deposit a coating having the desired properties.
  • WO-A-2009/00745 discloses flame pyrolysis processes for deposition of anti reflective coatings upon the surface of a continuous glass substrate. Another process for the deposition of silica coatings having a refractive index of 1.45 or greater on to the glass substrate formed during a float glass production process is disclosed in WO 2005/023723.
  • the present invention accordingly provides, in a first aspect, a process for the deposition of an anti-reflection coating on a substrate, the process comprising providing a substrate at a substrate temperature of 100°C to 350°C, passing a fluid mixture comprising a coating precursor through a flame, and contacting at least one surface of the substrate with the coating precursor during or after its passage through the flame.
  • coatings deposited at this relatively low temperature are both durable and have excellent anti reflection properties.
  • the substrate temperature is 105 to 310°C, 105 to 300°C, 105 to 250°C, more preferably 105 to 200°C and most preferably 105 to 190°C.
  • the most preferred temperature range is 160 to 190°C. Deposition on to substrates at a temperature of greater than 100°C is advantageous because it results in good coatings without requiring a subsequent heating step (which is time consuming and relatively inefficient in production).
  • the fluid mixture preferably further comprises a comburant and/or a carrier fluid (preferably a carrier gas).
  • a carrier fluid preferably a carrier gas.
  • the fluid mixture preferably further comprises an oxidant which will usually be oxygen e.g. from air.
  • the amount of oxidant in the fluid mixture is such that the parameter ⁇ ox idant,
  • a ox idant is the amount of oxidant
  • Aoxcomburant is the amount of oxidant necessary to fully oxidise the comburant
  • Aa Ixprecursor is the amount of oxidant necessary to fully oxidise the coating precursor.
  • ox idaiit is less than 1.3, more preferably less than 1.2 and most preferably 1 or lower.
  • the present invention provides, in a second aspect, a process for the deposition of an anti reflection coating on a substrate, the process comprising providing a substrate, passing a fluid mixture through a flame, the fluid mixture comprising a coating precursor, an oxidant, and, optionally, a comburant, contacting at least one surface of the substrate with the fluid mixture during or after its passage through the flame, characterised in that the amount of oxidant in the fluid mixture is such that the parameter ⁇ 0 , ⁇ ⁇ :,
  • a ox idant is the amount of oxidant
  • Aoxcomburant is the amount of oxidant needed for complete combustion of the comburant
  • Aoxprecursor is the amount of oxidant needed for complete combustion of the coating precursor.
  • the refractive index of the anti reflection coating is preferably 1.25 to 1.4 to provide good anti-reflection properties.
  • the effective refractive index varies with the porosity and the surface roughness of the deposited coating. These parameters are influenced by the temperature of the substrate, by the material from which the anti reflection layer is formed and the precursor of that material that is used and by the conditions under which the process is carried out.
  • the anti reflection coating will comprise a porous portion which is advantageous because a porous portion of e.g. a silicon oxide coating generally has a lower refractive index.
  • the fluid mixture comprises a silicon oxide, preferably silica
  • coating precursor and the anti reflection coating comprises a silicon oxide, preferably silica.
  • precursors which may be used in the formation of silicon oxide, preferably silica, coatings include compounds having the general formula SiX 4 wherein the groups X, which may be the same or different, represent a halogen atom especially a chlorine atom or a bromine atom, a hydrogen atom, an alkoxy group having the formula - OR or an ester group having the formula -OOCR wherein R represents an alkyl group comprising from 1 to 4 carbon atoms.
  • Particularly preferred precursors for use in the present invention include tetraethoxysilane (TEOS), hexamethyldisiloxane (HMDSO) and silane.
  • the precursor is directed to the substrate surface at a flow rate of 2 to 25 m/min, more preferably 3 to 21 m/min and most preferably 4 to 16 m/min (where the units are derived from chemical flow (in m 3 min _1 ) ⁇ burner face area (in m 2 ) to take account of flow rates in burners of different face areas.)
  • flow rates are advantageous because they result in excellent coatings with good properties.
  • the anti reflection coating is deposited to a thickness of 10 to 500 nm.
  • the thickness of the coating is greater than 25 nm, 40 nm, 50 nm, 80 nm or 100 nm and most preferably 105 to 500 nm. This is advantageous because it enables good anti- reflection properties to be provided. Very thin coatings are generally not significantly anti- reflective.
  • the thickness of the coating is preferably that which will result in destructive interference between the light reflected from the surface of the coating and the surface of the glass.
  • the length of the optical path in the coating should be equal to one half of the wavelength of the light. This thickness can be calculated from the equation: where t is the thickness of the coating, ⁇ is the wavelength of the incident light and n is the refractive index of the coating.
  • the substrate comprises glass, especially float glass (i.e. glass manufactured by the float glass process) or rolled glass. It is advantageous if the glass has an iron content of 0.015% by weight or lower because this tends to increase the visible light transmission.
  • the process of the invention may be conducted on line or off-line. If conducted on line during the float glass production the substrate will generally be a ribbon of float glass.
  • the coating if deposited on float glass, may be deposited on the gas side surface of float glass, but is preferably deposited on the tin side surface of float glass. This is advantageous because subsequent coating of the coated substrate may then be performed directly on the gas side surface of the glass.
  • the process may further comprise a step of depositing at least one further coating either on the same surface as the anti reflection coating or on another (or the other) surface.
  • The, or each, further coating may be deposited before, during (if on the other surface), or after deposition of the anti reflection coating.
  • One possible further coating is a coating of a transparent conductive oxide.
  • Transparent conductive oxide coatings include coatings of doped tin oxide, doped zinc oxide or indium oxides (e.g. indium tin oxide, ITO).
  • the coatings deposited by the process are of much better quality if the deposition is conducted when the flame is substantially stable.
  • Flame deposition processes usually comprise the steps of forming a fluid mixture comprising a precursor of an oxide of a metal or a metalloid, an oxidant and, optionally, a comburant. This fluid mixture may then be ignited at a point which is adjacent to the surface of the substrate.
  • the precursor for the oxide may be any compound of a metal or metalloid which may be dispersed in the fluid mixture and which will decompose to form an oxide when the mixture is ignited.
  • Processes in which the precursor is in the vapour phase are commonly termed combustion chemical vapour deposition processes (hereinafter for convenience CCVD processes).
  • the processes of this invention are CCVD processes.
  • the burner used in the flame deposition process preferably extends across the full width of the substrate although a series of smaller burners may be used.
  • the burner is preferably positioned above the substrate in close proximity to the surface of the glass substrate.
  • the distance between the burner and the substrate will typically be in the range of from 2 to 20 mm and preferably in the range 5.0 to 15.0 mm.
  • Such close proximity results in a coating having improved properties possibly because it minimises the amount of recombination between the species produced by burning the precursor before they are deposited upon the surface of the substrate. It may be necessary to adjust the distance between the burner and the surface of the glass substrate in order to optimise the properties of the desired coating.
  • a plurality of burners positioned along the length of the substrate may be used in order to deposit a coating having the desired thickness.
  • the thermal output of the burners useful in the processes of this invention may be from 0.5 to 10 kW/10cm 2 , preferably from 1 to 5 kW/10cm 2 .
  • the concentration of precursor in the fluid mixture which is delivered to the burner is typically from 0.05 to 25 vol%, preferably from 0.05 to 5 vol% gas phase concentration.
  • the burner is preferably associated with means for extracting the exhaust gases from the area adjacent to the surface of the substrate.
  • at least one means for extraction is positioned adjacent to each burner.
  • the extraction means is typically a conduit associated with a fan which produces an updraft at the mouth of the conduit.
  • Each extraction means is preferably provided with control means whereby the draft provided may be adjusted.
  • the extraction means are controlled so as to isolate the burner flames from each other, to control the direction of the flame so as to optimise the impingement of the flame over the surface of the substrate and to efficiently remove the by products which are generated by the combustion.
  • the inventors have discovered that the quality of the coating which is deposited can be improved by extracting the exhaust gases in a manner which causes the tail of the flame to be positioned above the surface of the substrate i.e. when the burner is located above the substrate surface the tail of the flame is also located above the substrate surface and when the burner is located below the substrate surface the tail of the flame is also below the substrate surface. Extracting the gases in this way has been found to reduce powder formation and to improve the uniformity of the coating. These are significant advantages, especially in an on line coating process where a high deposition speed is advantageous.
  • the temperature of the flame varies with the choice of comburant. Any gas which can be burnt to generate a sufficiently high flame temperature to decompose the precursor is potentially useful. Generally the comburant will be one which generates a flame temperature of at least 1700°C.
  • the preferred comburants include hydrocarbons such as propane, butane, acetylene, methane and natural gas or hydrogen.
  • the process uses an oxidant which may comprise a source of oxygen.
  • the oxidant may be air.
  • the ratio of precursor and/or comburant to oxidant e.g. air
  • the use of an oxygen rich flame favours the production of a fully oxidised coating whereas the use of an oxygen deficient flame favours the production of a coating which is less than fully oxidised.
  • the present invention provides, in a third aspect, a substrate having an anti reflection coating obtainable by a process as discussed above in the first and second aspects.
  • coated substrates provided by the present invention include in photovoltaic modules to increase visible light transmission and thereby improve efficiency of the module.
  • the present invention is illustrated by the Figure which is a graph of light transmission (%) against wavelength for Example 10 (see below).
  • the invention is also illustrated by the following Examples in which a fluid mixture comprising propane, air and hexamethyldisiloxane (HMDSO) was fed to a burner for flame deposition of silica coatings. Six passes of the substrate under the burner were made. The substrate was reduced iron ( ⁇ 0.015 wt %) float glass. Deposition conditions for the silica coatings were as indicated in Table 1.
  • the HMDSO precursor was introduced by syringe drive/evaporator (200 °C) directly into air flow.
  • HMDSO flow is given in m/min (chemical flow ⁇ burner face area) to allow comparison to burners of different size.
  • Table 2 is ordered by temperature of base glass.
  • T v is of base glass (without AR coating) for the examples was 90.3%.
  • T v i s values were calculated from the spectra of the samples to ISO9050 and EN410/673.
  • the silica coating significantly improves the transmission of light into PV cells with consequent improvement in efficiency. Surprisingly, the durability of the coatings did not appear to be affected by temperature of deposition and was good even at the low temperature (180°C ) deposition.
  • c-Si refers to crystalline silicon PV cell, CdTe to a cadmium telluride PV cell, a-Si to amorphous silicon PV cell, uc-Si to microcrystalline silicon PV cell and CIGS to copper indium gallium selenide PV cell.
  • Results for Example 2 are not reproduced in Table 2 or 3 because it was observed that the flame was not stable during deposition resulting in poor and uneven coating quality.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Surface Treatment Of Glass (AREA)
  • Surface Treatment Of Optical Elements (AREA)

Abstract

L'invention porte sur le dépôt par fusion de couches antireflets à une température relativement basse, lesquelles couches étant à la fois durables possédant d'excellentes propriétés antireflets. L'indice de réfraction est compris dans la plage de 1,25 à 1,40. Le mélange de couche contient un précurseur de couche, un oxydant (par exemple l'air) et facultativement un comburant (un hydrocarbure ou de l'hydrogène de façon à générer une flamme à une température plus élevée) et/ou un gaz porteur selon un rapport spécifié.
PCT/GB2010/052189 2009-12-22 2010-12-22 Procédé de dépôt Ceased WO2011077153A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0922395.9 2009-12-22
GB0922395A GB0922395D0 (en) 2009-12-22 2009-12-22 Deposition process

Publications (2)

Publication Number Publication Date
WO2011077153A2 true WO2011077153A2 (fr) 2011-06-30
WO2011077153A3 WO2011077153A3 (fr) 2011-10-06

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PCT/GB2010/052189 Ceased WO2011077153A2 (fr) 2009-12-22 2010-12-22 Procédé de dépôt

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WO (1) WO2011077153A2 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013014423A1 (fr) 2011-07-22 2013-01-31 Pilkington Group Limited Procédé de dépôt

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10146687C1 (de) 2001-09-21 2003-06-26 Flabeg Solarglas Gmbh & Co Kg Glas mit einer porösen Antireflex-Oberflächenbeschichtung sowie Verfahren zur Herstellung des Glases und Verwendung eines derartigen Glases
EP1328483A1 (fr) 2000-10-18 2003-07-23 Flabeg Solarglas GmbH & Co. KG Verre trempe thermiquement pourvu d'une couche antireflet en sio2, poreuse et resistante a l'usure
EP1429997A1 (fr) 2001-09-21 2004-06-23 MERCK PATENT GmbH Nouveau sol hybride pour la realisation de couches antireflets sio 2 resistantes a l'usure
WO2005023723A1 (fr) 2003-08-29 2005-03-17 Pilkington North America, Inc. Depot de couches de silice sur un substrat
US6918957B2 (en) 2000-10-18 2005-07-19 Merck Patent Gmbh Aqueous coating solution for abrasion-resistant SiO2 antireflection layers
US20060003108A1 (en) 2004-04-20 2006-01-05 Bernhard Zobel Method for production of transmission-enhancing and/or reflection-reducing optical coatings
WO2009000745A1 (fr) 2007-06-22 2008-12-31 Glaxo Group Limited Composés hétérocycliques pour le traitement de la tuberculose

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4237921A1 (de) * 1992-10-23 1994-04-28 Flachglas Ag Verfahren und Vorrichtung zum Modifizieren der Oberflächenaktivität eines Silikatglassubstrates
US20110287178A1 (en) * 2007-07-06 2011-11-24 Pilkington Group Limited Deposition process
US8440256B2 (en) * 2007-12-17 2013-05-14 Guardian Industries Corp. Combustion deposition of metal oxide coatings deposited via infrared burners

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1328483A1 (fr) 2000-10-18 2003-07-23 Flabeg Solarglas GmbH & Co. KG Verre trempe thermiquement pourvu d'une couche antireflet en sio2, poreuse et resistante a l'usure
US6918957B2 (en) 2000-10-18 2005-07-19 Merck Patent Gmbh Aqueous coating solution for abrasion-resistant SiO2 antireflection layers
DE10146687C1 (de) 2001-09-21 2003-06-26 Flabeg Solarglas Gmbh & Co Kg Glas mit einer porösen Antireflex-Oberflächenbeschichtung sowie Verfahren zur Herstellung des Glases und Verwendung eines derartigen Glases
EP1429997A1 (fr) 2001-09-21 2004-06-23 MERCK PATENT GmbH Nouveau sol hybride pour la realisation de couches antireflets sio 2 resistantes a l'usure
WO2005023723A1 (fr) 2003-08-29 2005-03-17 Pilkington North America, Inc. Depot de couches de silice sur un substrat
US20060003108A1 (en) 2004-04-20 2006-01-05 Bernhard Zobel Method for production of transmission-enhancing and/or reflection-reducing optical coatings
WO2009000745A1 (fr) 2007-06-22 2008-12-31 Glaxo Group Limited Composés hétérocycliques pour le traitement de la tuberculose

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013014423A1 (fr) 2011-07-22 2013-01-31 Pilkington Group Limited Procédé de dépôt

Also Published As

Publication number Publication date
WO2011077153A3 (fr) 2011-10-06
GB0922395D0 (en) 2010-02-03

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