|Title of Invention||
GLAZING PROVIDED WITH A THIN-FILM MULTILAYER ACTING ON SOLAR RADIATION
|Abstract||The subject of the invention is a transparent substrate, especially a glass substrate, provided with a thin-film multilayer acting on solar radiation, the multilayer being deposited by magnetron sputtering, characterized in that it includes at least a lubricating film of high optical index n, this lubricating film being associated with at least one sublayer, which is based on silicon nitride or oxynitride or carbonitride, or based on aluminum and/or zirconium nitride or oxynitride or carbonitride, or a mixture of at least two of these compounds (mixed Si-Al or Si-Zr nitrides or oxynitrides or carbonitrides).|
GLAZING PROVIDED WITH A THIN-FILM MULTILAYER
ACTING ON SOLAR RADIATION
The invention relates to glazing provided with thin-film multilayers
acting on solar radiation, especially glazing intended for thermal
insulation and/or solar protection.
This type of glazing is more particularly suitable for fitting into
buildings: by virtue of the thin films, it makes it possible, by varying the
amount of solar radiation energy, to prevent the interior of rooms being
excessively heated in the summer and thus helps to limit the consumption
of energy needed for air-conditioning them.
The invention also relates to this type of glazing once it has been
opacificd so as to form part of wall-cladding panels, which is called, more
concisely, "curtain walling" and which, in combination with window
glazing, makes it possible to provide buildings with exterior surfaces that
arc entirely glazed.
Such multilayer glazing (and curtain walling) is subjected to a
number of constraints: with regard to window glazing, the films employed
must filter out the solar radiation sufficiently. Furthermore, the thermal
performance must preserve the optical and esthetic appearance of the
glazing: it is desirable to be able to modulate the level of light transmission
of the substrate and to retain an esthetically attractive color, most
particularly in external reflection. This is also true of curtain walling with
regard to the appearance in reflection. These films must also be
sufficiently durable, this being the more so if, in the glazing once fitted,
they are on one of the exterior faces of the glazing (as opposed to the
"interior" faces turned toward the intermediate gas-filled cavity of a
double-glazing unit, for example).
Another constraint is imposed progressively: when the glazing
consists at least partly of glass substrates, these may have to undergo one
or more heat treatments, for example a bending operation if it is desired to
shape them (shop window) or a toughening or annealing operation if it is
desired to make them stronger/less hazardous in the event of impacts.
The fact that films are deposited on the glass before its heat treatment
means that there is a risk of them being damaged and their properties,
especially optical properties, being substantially modified (to deposit the
films after the glass has been heat-treated is complicated and expensive).
A first approach consists in modifying the optical appearance of the
glass due to the films after the heat treatment and in configuring the films
so that they have the desired properties, especially optical and thermal
properties, only after this treatment. But in fact this means having to
manufacture two types of multilayers in parallel, one for non-
toughened/non-curved glazing and the other for glazing which will be
toughened/curved. It is endeavored henceforth to avoid this by devising
multilayers of thin (intcrferential) films which are able to withstand heat
treatments without the optical properties of the glass being modified too
significantly and without its appearance being degraded (optical defects).
The films may then be referred to as "bendable" or "toughcnable" films.
An example of solar-protection glazing for buildings is given in
patents EP-0 511 901 and EP-0 678 483: these refer to functional films for
filtering out solar radiation that are made of a nickel-chromium alloy,
optionally nitrided, made of stainless steel or of tantalum and are placed
between two dielectric films of metal oxides such as SnO2, TiO2 or Ta2O;,.
Such glazing makes for good solar-protection glazing with satisfactory
mechanical and chemical durability, but is not truly "bendable" or
"toughenable" since the oxide films surrounding the functional film do not
prevent it from being oxidized during the bending or toughening operation,
the oxidation being accompanied by a modification in the light
transmission and in the general appearance of the glazing in its entirety.
Many studies have been carried out recently to make the films
bcndable/toughenable in the context of low-cmissivity glazing, in which
the aim is rather to achieve high light transmission as opposed to solar
protection. It has already been proposed to use, above the silver functional
films, dielectric films based on silicon nitride, this material being relatively
inert with respect to high-temperature oxidation and proving suitable for
preserving the subjacent silver film, as described in patent EP-0 718 250.
Other multilayers acting on solar radiation and assumed to be
bcndable/toughenable have been described, these employing functional
films other than silver: patent EP-0 536 607 uses functional films made of
a metal nitride, of the TiN or CrN type, with protective films made of metal
or of silicon derivatives; patent EP-0 747 329 describes functional films
made of a nickel alloy of the NiCr type that are combined with silicon
Multilayer structures are also known that use, as film acting on
solar radiation, titanium dioxide (TiO2), this film being pyrolytically
deposited in the float chamber, namely by thermally decomposing a liquid
or solid precursor of titanium-based precursors.
Although the product is satisfactory from the standpoint of
reflection properties with regard to solar radiation, its method of
manufacture no longer meets environmental regulations. This is because
the pyrolytic deposition technique requires the use of organomctallic
precursors in hydrocarbon-type solvents, which mean that the waste and
gaseous discharges have to undergo further treatment.
Furthermore, the pyrolytic deposition technique requires the use of
nozzles placed in the treatment chamber, facing the moving glass ribbon,
so as to be able to disperse the organometallic precursors as uniformly as
possible for the purpose of obtaining a film with optimum optical
However, these multilayers providing a solar-protection function
that arc deposited pyrolytically have reached performance levels that arc
not easily capable of being improved, considering the deposition technique
and the regulatory requirements.
The object of the invention is therefore to develop a novel type of
thin film multilayers acting on solar radiation, for the purpose of
manufacturing improved solar-protection glazing by a
magnetron-sputtering technique. The intended improvement is especially
to obtain a better compromise between durability, thermal properties,
optical properties and ability to withstand heat treatments without any
damage when the substrate carrying the multilayer is of the glass type.
The other object of the invention is to make this multilayer
compatible with the use of the glazing, once it has been opacificd, as
The subject of the invention is firstly a transparent substrate,
especially a glass substrate, provided with a thin-film multilayer acting on
solar radiation, the multilayer being deposited by magnetron sputtering,
which is characterized in that it includes at least a lubricating film of high
optical index n, this lubricating film being associated with at least one
sublayer, which is based on silicon nitride or oxynitride or carbonitride, or
based on aluminum and/or zirconium nitride or oxynitride or
carbonitride, or a mixture of at least two of these compounds (mixed Si-Al
or Si Zr nitrides or oxynitrides or carbonitrides).
The lubricating films of the invention allow the light transmission
value of the substrate to be varied within the desired ranges, as explained
in detail below, by adjusting their thicknesses, while still maintaining a
solar protection effect.
The presence of the sublayer makes it possible to vary, more flexibly,
the optical appearance conferred by the multilayer on its carrier substrate.
Furthermore, in the case of heat treatment, it constitutes an additional
barrier, especially with respect to oxygen and alkaline metals from the
glass substrate, which species arc liable to migrate toward the heat and to
degrade the multilayer.
Furthermore, the choice of an overlayer based on silicon nitride or
silicon oxide (abbreviated to Si3N4 and SiO2) or on silicon oxynitride
(abbreviated to SiON, without prejudicing the respective amounts of Si, O
and N) has also proved to be highly advantageous on several counts: this
type of material proves to be capable of protecting the films of the
multilayer (the lubricating layer and the sublayer) of the invention at high
temperature, especially from oxidation, while maintaining their integrity,
thereby making the multilayer according to the invention
bendable/toughcnablc when the substrate carrying the multilayer is made
of glass and when it is desired for said multilayer to undergo a heat
treatment of this type after deposition of the films: the change in optical
properties caused by a heat treatment of the toughening type is slight,
with the light transmission and external appearance in reflection both
being modified sufficiently slightly not to be significantly perceptible to the
Finally, it has been discovered that it is also compatible with a
subsequent enameling treatment, this being most particularly
advantageous in the case of curtain walling, since in general there are two
possible ways of opacifying the glazing for curtain walling: either a lacquer
is deposited on the glass, which is dried and cured with a moderate heat
treatment, or an enamel is deposited.
The enamel, like that usually deposited, is composed of a powder
containing a glass frit (the glassy matrix) and pigments used as colorants
(the frit and the pigments being based on metal oxides), and a medium
also called a vehicle, allowing the powder to be applied to the glass and to
adhere to it at the time of deposition. To obtain the final enameled coating,
it must then be fired, and this firing operation is frequently carried out
concomitantly with the operation of toughening/bending the glass.
Reference may be made for further details about the enamel compositions
to patents FR-2 736 348, WO 96/41773, EP-718 248, EP-712 813 and
ICP-636 588. The enamel, a mineral coating, is durable, adherent to the
glass and therefore a useful opacifying coating. However, when the glazing
is provided beforehand with thin films, it is tricky to use it for two reasons:
- on the one hand, firing the enamel necessarily means subjecting
the multilayer to a high-temperature heat treatment, which is possible
only if the multilayer is capable of not being optically degraded during this
- on the other hand, over time the enamel tends to release chemical
substances which diffuse into the subjacent films and chemically modify
However, using a silicon nitride or oxynitride or silicon oxide film to
complete the thin-film multilayers has been very effective both for making
the overall multilayer capable of withstanding the heat treatments and for
acting as a barrier to these chemical compounds liable to diffuse out of the
Consequently, the multilayer according to the invention is
enamelablc in the sense that an enamel can be deposited on the face of
the substrate that is not coated with the multilayer and fired without
appreciably changing the optical appearance, with respect to window
glazing provided with the same films, in external reflection. This is
precisely the challenge for curtain walling, namely to provide harmony of
color and as far as possible similarity of external appearance with the
window glazing so as to be able to form entirely glazed walls which are
According to another embodiment, not exclusive of the previous one,
provision may be made to use multiple sublayers, especially having an
alternation of high refractive index (for example between 1.8 and 2.2) and
low refractive index (for example between 1.4 and 1.6). These are
preferably sequences of the SiaN4 (index ~ 2)/SiO2 (index ~ 1.45) or
Si3N4/SiO2/Si3N4 type. These sequences allow the external appearance of
the substrate in reflection to be adjusted, especially for the purpose of
reducing the value of R1 and/or its color.
Moreover, the film or films of the multilayer which are based on
silicon nitride or oxynitride also contain a metal in a minor amount with
respect to silicon, for example aluminum, especially up to 10% by weight
of the compound constituting the film in question. This is useful for
increasing the rate of deposition of the film by magnetically enhanced
reactive sputtering, in which the silicon target without any "doping" with a
metal is not conducting enough. The metal may furthermore confer better
durability on the nitride or oxynitride.
With regard to the thicknesses of the films described above, it is
usual to choose a thickness range from 5 to 50 nm for the lubricating film,
especially between 5 and 30 nm. The choice of its thickness allows the
light transmission of the substrate to be varied within ranges used for
glazing providing buildings with solar protection, i.e. especially 50 to 80%
or 60 to 70%. Of course, the light transmission level may also be modified
using other parameters, especially the thickness and the composition of
the substrate, most particularly when it is made of clear or colored glass.
The thickness of the sublayer is preferably between 5 and 70 nm,
especially between 10 and 35 nm. For example, it is 15, 20 or 25 nm.
The thickness of the optional ovcrlayer is preferably between 1 and
10 nm, especially between 2 and 7 nm.
When there is a single sublayer, of the Si3N4 type, its thickness, is,
for example, 5 to 50 nm, especially about 10 to 30 or 25 nm. When it is a
sequence of several films, each of the films may have a thickness of, for
example, 5 to 50 nm, especially 1 5 to 45 nm.
The sublayer and/or the overlayer may in fact form part of a
superposition of dielectric films. One or other may thus be combined with
other films of different refractive indices. Thus, the multilayer may
include, between the substrate and the functional film (or above the
functional film) an alternation of three, high index/low index/high index,
films, the "high index" (at least 1.8 to 2) film or one of them possibly being
the sublayer of the invention of the Si3N4 or A1N type and the "low index"
(for example less than 1.7) film possibly being made of silicon oxide SiO2.
The thickness of the additional metal nitride film is preferably
between 2 and 20 nm, especially between 5 and 10 nm. It: is therefore
preferably thin and therefore possibly contributes only very slightly to the
solar protection effect imparted by the metal film.
A preferred embodiment of the invention is a multilayer that
includes a lubricating film based on titanium dioxide (TiO2) or zirconium
dioxide (ZrO2) or a mixture of titanium oxide and zinc oxide (OTiZn) or a
mixed silicon zirconium nitride (SiZrN), a sublayer based on silicon nitride
and an optional overlayer, also based on silicon nitride (Si4N4) or silicon
The subject of the invention is also a substrate provided with the
multilayer which is described above, in general, and is bendable and/or
toughenable and/or enamelable. A multilayer which is "bendable and/or
toughenable" is understood within the meaning of the invention to be a
multilayer which, deposited on the substrate, undergoes a limited optical
change and may especially be quantified within the (L*,a*,b*) colorimetry
system by a AE* value of less than 3, especially less than 2.
AE* is defined as follows: AE* = (AL*2 + Aa*2 + Ab*2)1^, where AL*, Aa*
and Ab* are the differences in the L*, a* and b* measurements before and
after heat treatment.
That face of the substrate not provided with a multilayer is
considered as "enamelable" when it is possible to deposit on it, in a known
manner, an enamel composition without the appearance of optical defects
in the multilayer (which is on the other face of the substrate) and with a
limited optical change, which may be quantified as above. This also means
that it has a satisfactory durability, without any undesirable deterioration
of the films of the multilayer in contact with the enamel, either while it is
being fired or over time once the glazing has been fitted.
Of course, a multilayer of this type is advantageous when substrates
made of clear or bulk-tinted glass are used. However, it is possible just as
well not to seek to exploit its bendable/toughcnable nature but simply its
satisfactory durability, by using glass substrates but also substrates not
made of glass, especially made of a rigid and transparent polymer material
such as polycarbonate or polymethyl methacrylatc (PMMA) substituting
for the glass, or else a flexible polymer material, like certain polyurethanes
or like polyethylene tcrephthalate (PET), which flexible material can then
be fastened to a rigid substrate in order to functionalizc it, by making
them adhere by various means, or by a lamination operation.
The subject of the invention is also "monolithic" glazing (i.e. glazing
comprising a single substrate) or insulating multiple glazing of the double
glazing type. Preferably, whether monolithic glazing or double glazing, the
multilayers are placed on the 2 face (conventionally, the glass/substrate
faces of a glazing assembly are numbered from the outside toward the
inside of the compartment/room which is fitted therewith) and provide a
solar-radiation protection effect.
More particularly, advantageous glazing according to the invention
has a TL of about 50 to 80%, especially 60 to 70%, and a solar factor SF
close to the TL value. It also has preferably a blue or green color in external
reflection (on that side of the substrate which is not provided with films)
especially with, in the (L*,a*,b*) colorimetry system, negative a* and b*
values (before and after any possible heat treatment). Thus, an attractive
and not very strong color in reflection, desirable in buildings, is obtained.
The subject of the invention is also a substrate with a multilayer
and partially opacificd by a coating of the lacquer or enamel type, for the
purpose of making curtain walling, in which the opacifying coating is in
direct contact with the face of the substrate that is not coated with the
multilayer. The multilayer can therefore be absolutely identical both for
window glazing and for curtain walling.
Although the application more particularly intended by the
invention is glazing for buildings, it is clear that other applications can be
envisaged, especially for vehicle windows (apart from windshields, in
which a very high light transmission is required), such as the side
windows, sunroof and rear window.
The invention will be described below in greater detail with the aid of
All the substrates are made of 6 mm-thick clear glass of the
PLANILUX type sold by Saint-Gobain Glass France.
All the films arc deposited in a known manner by magnetically
enhanced sputtering, the metal films using a metal target in an oxidizing
atmosphere in the case of TiOa, the metal nitride or silicon nitride films
using a suitable metal or silicon (bulk-doped with 8% aluminum) target in
a reactive atmosphere containing nitrogen (100% N2 for TiN and 40%
Ar/60% N2 for Si3N4). The Si3N4 films therefore contain a little aluminum.
This example uses a TiO2 lubricating film and an Si3N4 sublayer
according to the following sequence:
glass / Si3N4 (25 nm)/TiO2 (20 nm).
After depositing the films, the substrate underwent the following
heat treatment: 620°C heating for 10 minutes.
This example uses the same lubricating film and the same sublayer
as in Example 1, with an additional SiO2 ovcrlaycr according to the
glass / Si3N4 (20 nm) / TiO2 (20 nm) / SiO2 (5 nm).
The coated substrate then underwent the same heat treatment as in
Table 1. below combines, for Examples 1, 2, the following properties:
- optical transmission TL: light transmission in % under illuminant
external reflection (i.e. that measured on the external side when
the coated glass is fitted as monolithic glazing in a room with the
multilayer on face 2: external reflection (RLEXT) in %; a* (REXT), b*(REXT), the
colorimctric coordinates in external reflection according to the (L*,a*,b*)
internal reflection: the value of RLINT in % and the colorimctric data
a*(RINT), b*(RINT); and
- energy transmission: TE in %.
All these properties are given twice: once before heat treatment and
once after heat treatment. Also measured arc E*(T) in transmission,
E*(REXT) in external reflection and E*(RINT) in internal reflection, where
E* (L*2 + a*2 + b*2)1/2 for transmission, with:
a* = a* (after treatment) - a* (before treatment);
b* = b* (after treatment) - b* (before treatment);
L* = L* (after treatment) - L* (before treatment).
This table shows that Examples 1 and 2 according to the invention
provide a good E* before heat treatment/E* after heat treatment
compromise (little variation) and they provide good solar protection. They
are also good from the point of view of esthetic appearance, most
particularly in external reflection where the a* and b* values are negative
giving a color in the blue-green that is not very strong, regarded as
attractive for glazing with strong external reflection.
What is notable is that all these advantages are retained after heat
treatment: the TL and TE values are retained to within 1%, the colorimetric
data change very little and there is no switch from one color to another in
external reflection. There are no optical defects. The AE* value, quantifying
a possible colorimetric change, remains at most 1.2 in transmission, in
internal reflection and in external reflection: this is indeed a multilayer
capable of undergoing a treatment of the bending or toughening type
without significant degradation. Whether it is desired to have a glass
which may or may not be toughened, annealed or curved, the invention
provides a solar-protection multilayer with identical, retained, properties.
The comments made with regard to Example 1 also apply to Example 2,
except as regards the value of AE* in transmission, which is substantially
less than the corresponding value in both internal and external reflection.
In conclusion, the solar-protection glazing according to the invention
is highly advantageous for fitting into buildings, but not to the exclusion
of applications in automobiles and any other vehicle: side windows, rear
window and sunroof, which may also have enameled coatings. With a fixed
multilayer, especially with the desired T1, and TE values, it is thus possible,
without having to modify the multilayer, to manufacture window glazing
which is not intended to undergo heat treatments or which must be
bent/toughcncd/anncaled and to manufacture curtain walling in
complete colorimetric harmony with the window glazing, which may be
lacquered or enameled: it is thus possible to standardize the manufacture
of interfcrential films on large-sized substrates, this being a great
advantage from the industrial standpoint.
The invention has resulted in the development of toughenable
solar control glazing with E* values in external reflection of 1.2 or less.
It is also possible to make enameled, rather than lacquered,
multilayer-coated curtain walling, this also being highly advantageous
from an industrial standpoint (the enameling taking place during the
toughening process, whereas lacquering requires an additional
1. A transparent substrate, espeeially a glass substrate, provided with
a thin-film multilayer acting on solar radiation, the multilayer being
deposited by magnetron sputtering, characterized in that it includes at
least a lubricating film of high optical index n, this lubricating film being
associated with at least one sublayer, which is based on silicon nitride or
oxynitridc or carbonitride, or based on aluminum and/or zirconium
nitride or oxynitride or carbonitride, or a mixture of at least two of these
compounds (mixed Si-Al or Si-Zr nitrides or oxynitrides or carbonitrides).
2. A transparent substrate provided with a thin-film multilayer acting
on solar radiation, characterized in that said multilayer includes at least
one lubricating film based on a partially or entirely oxidized metal, said
metal belonging to the group consisting of titanium and zirconium, said
lubricating film being associated with at least one sublayer based on
silicon nitride or oxynitride or carbonitride, or based on aluminum and/or
zirconium nitride or oxynitride or carbonitride, or a mixture of at least two
of these compounds (Si-Al or Si-Zr mixed nitrides or oxynitrides or
3. The substrate as claimed in claim 1 or 2, characterized in that the
multilayer also includes, on top of the lubricating film, at least one
overlayer made of a transparent dielectric, especially one chosen from
silicon nitride and/or aluminum nitride, silicon oxynitride and/or
aluminum oxynitride and silicon oxide.
4. The substrate as claimed in one of the preceding claims,
characterized in that the multilayer includes a plurality of sublayers
between the substrate and the functional film, especially an alternation of
high index and low-index films, such as Si3N4/SiO2. or Si3N4/SiO2/Si3N4.
5. The substrate as claimed in one of the preceding claims,
characterized in that the lubricating film has a thickness of between 5 and
50 nrn, especially between 5 and 30 nm.
6. The substrate as claimed in one of the preceding claims,
characterized in that the thickness of the sublayer is between 5 and
70 nm, especially between 10 and 35 nm.
7. The substrate as claimed in one of the preceding claims,
characterized in that the thickness of the optional overlayer is preferably
between 1 and 10 nm, especially between 2 and 7 nm.
8. The substrate as claimed in one of the preceding claims,
characterized in that the multilayer uses a titanium dioxide lubricating
film, a silicon nitride sublayer and an optional overlayer, also made of
silicon nitride or silicon dioxide.
9. The substrate as claimed in one of the preceding claims,
characterized in that it is bendable/toughenable and/or enamclablc.
10. The substrate as claimed in one of the preceding claims,
characterized in that it is made of glass, whether clear or bulk-tinted, or
made of a flexible or rigid, transparent polymer material.
11. A monolithic glazing or double glazing incorporating the substrate
as claimed in one of the preceding claims, the thin-film multilayer
preferably being on face 2, numbering the substrate faces from the outside
toward the inside of the compartment/room which is fitted therewith,
giving the glazing a solar radiation protection effect.
12. The glazing as claimed in claim 10, characterized in that it has a
light transmission TL of 50 to 80%, or 60 to 75%, and a solar factor SE
close to the TL value.
13. The glazing as claimed in claim 10 or 11, characterized in that it is
blue or green in external reflection, on the substrate side, with, in
particular, negative a* and b* values.
1.4. The substrate as claimed in one of claims 1 to 9, characterized in
that it is at least partially opacified by a coating in the form of a lacquer or
15. A wall-cladding panel, of the curtain-walling type, incorporating the
opacified substrate as claimed in claim 14.
The subject of the invention is a transparent substrate, especially a glass substrate, provided with a thin-film multilayer acting on solar radiation, the multilayer being deposited by magnetron sputtering, characterized in that it includes at least a lubricating film of high optical index n, this lubricating film being associated with at least one sublayer,
which is based on silicon nitride or oxynitride or carbonitride, or based on aluminum and/or zirconium nitride or oxynitride or carbonitride, or a mixture of at least two of these compounds (mixed Si-Al or Si-Zr nitrides
or oxynitrides or carbonitrides).
|Indian Patent Application Number||395/KOLNP/2008|
|PG Journal Number||14/2014|
|Date of Filing||29-Jan-2008|
|Name of Patentee||SAINT-GOBAIN GLASS FRANCE|
|Applicant Address||18, AVENUE D'ALSACE, F-92400 COURBEVOIE, FRANCE, A FRENCH COMPANY|
|PCT International Classification Number||C03C 17/34|
|PCT International Application Number||PCT/FR2006/050727|
|PCT International Filing date||2006-07-18|