Glazing provided with a stack of thin films acting on the sunlight

0001The invention relates to glazing provided with stacks of thin layers acting on solar radiation, in particular those intended for thermal insulation and / or solar protection.

0002This type of glazing is more particularly suitable for equipping buildings: by acting, thanks to the thin layers, on the amount of energy of the solar radiation, it makes it possible to avoid inside the premises an excessive heating in summer and thus contributes to limit the energy consumption necessary for their air conditioning.

0003The invention also relates to this type of glazing once opacified so as to be part of a facade cladding panel, more concisely called light, and which makes it possible, in association with glazing for vision, to offer exterior surfaces of fully glazed buildings.

0004These layered glazing (and lighters) are subject to a certain number of constraints: with regard to glazing, the layers used must be sufficiently filtering with respect to solar radiation. In addition, these thermal performances must preserve the optical appearance, the aesthetics of the glazing: it is desirable to be able to modulate the level of light transmission of the substrate, and to keep an aesthetic color, in particular in external reflection. This is also true of the lighters with regard to the aspect in reflection. These layers must also be sufficiently durable, and this is all the more so if, in the glazing once mounted, they are on one of the outer faces of the glazing (as opposed to the "inner" faces, facing the interlayer of gas. double glazing for example).

0005Another constraint is gradually imposed: when the glazing consists at least in part of glass substrates, these may have to undergo one or more heat treatments, for example a bending if it is desired to give them a curve (window), a quenching or annealing if you want them to be more resistant / less dangerous in the event of impact. The fact that layers are deposited on the glass before its heat treatment risks causing their deterioration and a significant modification of their properties, in particular optical properties (depositing the layers after the heat treatment of the glass is complex and costly).

0006A first approach consists in providing for the change in optical appearance of the glass due to the layers after the heat treatment, and in configuring the layers so that they do not exhibit the desired properties, in particular optical and thermal, only after this treatment. But in fact, this means that two types of layer stacks have to be produced in parallel, one for the non-toughened / non-curved glazing and the others for the glazing which will be toughened / curved. We are now trying to avoid this, by designing stacks of thin (interference) layers which can be able to withstand heat treatments without modifying the optical properties of the glass too significantly and without degrading its appearance (optical defect). We can then speak of "bendable" or "quenchable" layers.

0007An example of anti-solar glazing for the building is given by patents <patcit id="pcit0001" dnum="EP0511901A"><text>EP-0 511 901</text></patcit> and <patcit id="pcit0002" dnum="EP0678483A"><text>EP-0 678 483</text></patcit> : these are functional layers in terms of filtration of solar radiation which are made of nickel-chromium alloy, possibly nitrided, made of stainless steel or tantalum, and which are placed between two layers of dielectric made of metal oxide such as SnO₂, TiO₂ or your₂O₅. These glazings are good anti-solar glazings, having satisfactory mechanical and chemical durability, but are not really "bombable" or "quenchable", because the oxide layers surrounding the functional layer cannot prevent its oxidation during bending or tempering, oxidation accompanied by a modification of the light transmission, and of the appearance in general of the glazing as a whole.

0008Many studies have been carried out recently to make the layers bumpable / hardenable in the field of low-emissivity glazing, rather targeting high light transmissions unlike anti-solar. It has already been proposed to use, above silver functional layers, dielectric layers based on silicon nitride, this material being relatively inert with respect to high temperature oxidation and proving suitable for preserving the underlying silver layer, as described in the patent <patcit id="pcit0003" dnum="EP0718250A"><text>EP-0 718 250</text></patcit>.

0009Other stacks of layers acting on solar radiation presumed to be bendable / hardenable have been described, using functional layers other than silver: the patent <patcit id="pcit0004" dnum="EP0536607A"><text>EP-0 536 607</text></patcit> uses functional layers of metallic nitride, of the TiN or CrN type, with protective layers of metal or of silicon derivatives, the patent <patcit id="pcit0005" dnum="EP0747329A"><text>EP-0 747 329</text></patcit> describes functional nickel alloy layers of the NiCr type associated with layers of silicon nitride.

0010Stacking structures are also known using as a layer acting on the solar radiation titanium dioxide (TiO₂), this layer being deposited in the enclosure of the float by a pyrolytic route, namely a decomposition by heat of liquid or solid precursor of precursors based on titanium.

0011Although the product is satisfactory from the point of view of its properties of reflection with respect to solar radiation, its method of manufacture no longer meets environmental regulatory requirements. Indeed, the pyrolytic deposition technique requires the use of organometallic precursors in hydrocarbon-type solvents, requiring reprocessing of waste and gaseous discharges.

0012In addition, the pyrolytic deposition technique requires the use of nozzles arranged in the treatment enclosure and facing the glass ribbon in circulation in order to be able to disperse the organometallic precursors as homogeneously as possible for the purpose of obtaining a layer with optimal optical properties.

0013However, these stacks with an anti-solar function deposited by the pyrolytic route have achieved performances which are hardly likely to improve, if the deposition technique and the regulatory requirements are considered.

0014The object of the invention is then to develop a new type of stacks of thin layers acting on solar radiation, with a view to manufacturing, by a magnetron spraying technique, improved sun protection glazing. The improvement targeted is in particular the establishment of a better compromise between durability, thermal properties, optical properties and ability to withstand thermal treatments without damage when the substrate carrying the stack is of the glass type.

0015The other object of the invention is to make this stack of layers compatible with the use of the glazing, once opacified, as a lighter.

0016The invention relates to a transparent glass substrate provided with a stack of thin layers acting on solar radiation, the stack of layers being deposited by magnetron sputtering, comprising at least one lubricating layer with a high optical index n , this lubricating layer being associated with at least one sublayer, which is based on silicon nitride. More precisely, the subject of the invention is a substrate according to the claims below.

0017The lubricant layers of the invention allow the light transmission value of the substrate to be adjusted in the desired ranges detailed below, by adjusting their thicknesses, while retaining an anti-solar effect.

0018The presence of the sub-layer makes it possible to more flexibly modulate the optical appearance imparted by the stack of layers to its carrier substrate. In addition, in the case of heat treatment, it constitutes an additional barrier, in particular with respect to oxygen and alkalis of the glass substrate, species liable to migrate under heat and to degrade the stack.

0019In addition, the choice of an overcoat based on silicon nitride or silicon oxide (Si₃NOT₄ and SiO₂ for short) has also proven to be very advantageous for several reasons: this type of material has been found capable of protecting the layers of the stack (the lubricating layer and the sublayer) of the invention at high temperature, in particular with respect to oxidation, while preserving their integrity , which made the stack according to the invention bendable / hardenable in the case where the substrate carrying the stack is made of glass and that it is desired to subject it to such a heat treatment after deposition of the layers: the modification of the optical properties induced by a heat treatment of the quenching type is low with a light transmission and an appearance in external reflection sufficiently modified so as not to be significantly perceptible to the human eye.

0020Finally, it has been discovered that it is also compatible with a subsequent enamel treatment, which is of particular interest to the lighters. In fact, in order to opacify lighted glazing, there are generally two possible routes: either deposit a lacquer on the glass, which is dried and hardened with a moderate heat treatment, or deposit an enamel.

0021The enamel as it is deposited in the usual way is composed of a powder containing a glass frit (the vitreous 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 application of the powder to the glass and its adhesion with the latter at the time of deposition. To obtain the final enamel coating, it must then be baked, and it is common for this baking operation to be carried out concomitantly with the tempering / bending operation of the glass. Reference may be made for more details to patent enamel compositions.<patcit id="pcit0006" dnum="FR2736348"><text>FR-2 736 348</text></patcit>, <patcit id="pcit0007" dnum="WO9641773A"><text>WO96 / 41773</text></patcit>, <patcit id="pcit0008" dnum="EP718248A"><text>EP-718,248</text></patcit>, <patcit id="pcit0009" dnum="EP712813A"><text>EP-712 813</text></patcit>, <patcit id="pcit0010" dnum="EP636588A"><text>EP-636,588</text></patcit>. The enamel, mineral coating, is durable, adherent to glass and therefore an interesting opacifying coating. However, when the glazing is previously provided with thin layers, its use is delicate for two reasons:<ul id="ul0001" list-style="dash" compact="compact"><li>on the one hand, baking the enamel means having to subject the stack of layers to a high temperature heat treatment, which is only possible if the latter is capable of not deteriorating optically during this treatment,</li><li>on the other hand, the enamel tends to release over time chemical substances which come to diffuse in the underlying layers and modify them chemically.</li></ul>

0022However, using a nitride or silicon oxide layer to complete the stacking of thin layers has been very effective, both to make the entire stack capable of withstanding heat treatments and to act as a barrier to these compounds. chemicals that can diffuse out of the enamel layer.

0023In fact, the stack of layers according to the invention is glazable, in the sense that it is possible to deposit on the face of the substrate not coated with the stack of layers and to bake it without substantially modifying the optical appearance thereof with respect to vision glazing with the same layers, in external reflection. And this is precisely the issue of the lighters, namely to offer a harmony of color, the greatest possible similarity in external appearance with the glazing, in order to be able to constitute aesthetic entirely glazed facades.

0024Furthermore, the layer or layers of the stack which are based on nitride also contain a minority metal with respect to silicon, for example aluminum, in particular up to 10% by weight of the compound constituting the layer in question. This is useful for accelerating the deposition of the layer by sputtering assisted by magnetic field and reactive, where the target in silicon without a "doping" by a metal is not sufficiently conductive. The metal can also give nitride better durability.

0025With regard to the thicknesses of the layers described above, a thickness range of 5 to 50 nm is chosen for the lubricating layer, in particular between 5 and 30 nm. The choice of its thickness makes it possible to modulate the light transmission of the substrate in ranges used for sun protection glazing for the building, namely in particular from 50 to 80% or from 60 to 70%. Of course, the level of light transmission can also be modified using other parameters, in particular the thickness and composition of the substrate, whether it is made of clear or particularly colored glass.

0026The thickness of the sublayer is between 5 and 70, in particular between 10 and 35 nm. It is for example 15, 20 or 25 nm.

0027The thickness of the overcoat is between 1 and 10 nm, in particular between 2 and 7 nm.

0028When it is a single underlay, of the Si type₃NOT₄, it is for example from 5 to 50 nm, in particular about 10 to 30 or 25 nm.

0029The subject of the invention is the substrate provided with the stack of layers described in the claims below, in general, and which is bendable and / or hardenable and / or enamelled. For the purposes of the invention, the term “bombable and / or hardenable” means a stack, which, deposited on a substrate, undergoes a limited optical evolution, which can in particular be quantified by placing it in the colorimetry system (L *, a *, b *), by a value ΔE * less than 3, in particular less than 2.

0030ΔE * is defined as follows: <maths id="math0001"><math display="block"><msup><mi>ΔE</mi><mo>*</mo></msup><mo>=</mo><msup><mfenced><msup><mi>ΔL</mi><mrow><mo>*</mo><mn>2</mn></mrow></msup><mo>+</mo><msup><mi>Δa</mi><mrow><mo>*</mo><mn>2</mn></mrow></msup><mo>+</mo><msup><mi>Δb</mi><mrow><mo>*</mo><mn>2</mn></mrow></msup></mfenced><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup><mo>,</mo></math><img file="EP1919838B1_D0001.tif" /></maths>with ΔL *, Δa * and Δb * the difference in the measurements of L *, a * and b * before and after heat treatment.

0031We consider as "enamelable", the face of the substrate without stacking and on which one can deposit in a known manner an enamel composition, without appearance of optical defects in the stack (which is on the other face of the substrate) and with a limited optical evolution, which can be quantified as above. This also means that it has satisfactory durability, without annoying deterioration of the layers of the stack in contact with the enamel, neither during its firing, nor over time once the glazing is mounted.

0032Of course, a stack of this type is advantageous when using substrates made of clear glass or tinted in the mass. However, it is equally possible not to seek to exploit its bombable / quenchable nature, but simply its satisfactory durability, by using glass substrates.

0033The subject of the invention is "monolithic" glazing (that is to say consisting of a single substrate) or multiple insulating glazing of the double glazing type. Preferably, whether it is monolithic glazing or double glazing, the stacks of layers are arranged on face 2 (conventionally, the faces of the glasses / substrates of a glazing are numbered from the outside to the inside of the interior / of the room it equips), and provide a protective effect against solar radiation.

0034Glazing of particular interest to the invention has a T_L of the order of 50 to 80% or 60 to 70%, and a solar factor FS close to the value of T_L. They also preferentially have a blue or green color in external reflection (on the side of the substrate devoid of layers), with in particular in the colorimetry system (L *, a *, b *) negative values ​​of a * and b * (before and after any possible heat treatment). We thus have a pleasant shade and not very intense in reflection, sought after in the building.

0035The subject of the invention is also the substrate with layers at least partially opacified by a coating of lacquer or enamel type, with a view to making lighters, where the opacifying coating is in direct contact with the face of the substrate which is not coated. of the stack of layers. The stacking of layers can therefore be perfectly identical for vision glazing and for lighters.

0036If the application more particularly targeted by the invention is glazing for the building, it is clear that other applications are possible, in particular in vehicle glazing (apart from the windshield where very high light transmission), such as the side windows, the car roof, the rear window.

0037The invention will be described below in more detail with the aid of nonlimiting examples.

0038All the substrates are made of 6 mm thick clear glass of the Planilux type sold by the company Saint-Gobain Glass France.

0039All the layers are deposited in a known manner by sputtering assisted by magnetic field: the metal layers from a metal target in an oxidizing atmosphere for TiO₂ , the layers of metal or silicon nitride from the metal or silicon target (doped with 8% by mass of aluminum) suitable in a reactive atmosphere containing nitrogen (100% N₂ for TiN, 40% Ar and 60% N₂ for if₃NOT₄). The Si layers₃NOT₄ therefore contain a little aluminum.

<u>EXAMPLE 1</u>

0040This example uses a TiO lubricant layer₂ and an Si underlay₃NOT₄ according to the following sequence: <maths id="math0002"><math display="block"><mi>glass</mi><mo mathvariant="normal">/</mo><msub><mi>Yes</mi><mn mathvariant="normal">3</mn></msub><mo>⁢</mo><msub><mi mathvariant="normal">NOT</mi><mn mathvariant="normal">4</mn></msub><mspace width="1em" /><mfenced><mn mathvariant="normal">25</mn><mspace width="1em" /><mi>nm</mi></mfenced><mo mathvariant="normal">/</mo><msub><mi>TiO</mi><mn mathvariant="normal">2</mn></msub><mfenced><mn mathvariant="normal">20</mn><mspace width="1em" /><mi>nm</mi></mfenced></math><img file="EP1919838B1_D0002.tif" /></maths>

0041After deposition of the layers, the substrate undergoes the following heat treatment: heating at 620 ° C. for 10 minutes.

<u>EXAMPLE 2</u>

0042This example uses the same lubricating layer and the same undercoat as in Example 1, with an SiO overcoat₂ additional according to the following sequence: <maths id="math0003"><math display="block"><mi>glass</mi><mo mathvariant="normal">/</mo><msub><mi>Yes</mi><mn mathvariant="normal">3</mn></msub><mo>⁢</mo><msub><mi mathvariant="normal">NOT</mi><mn mathvariant="normal">4</mn></msub><mspace width="1em" /><mfenced><mn>20</mn><mspace width="1em" /><mi>nm</mi></mfenced><mo mathvariant="normal">/</mo><msub><mi>TiO</mi><mn mathvariant="normal">2</mn></msub><mfenced><mn mathvariant="normal">20</mn><mspace width="1em" /><mi>nm</mi></mfenced><mo>/</mo><msub><mi>SiO</mi><mn mathvariant="normal">2</mn></msub><mfenced><mn>5</mn><mspace width="1em" /><mi>nm</mi></mfenced></math><img file="EP1919838B1_D0003.tif" /></maths>the coated substrate then undergoes the same heat treatment as in Example 1.

0043Table 1 below groups together for Examples 1, 2 the following data:<ul id="ul0002" list-style="dash" compact="compact"><li>optical transmission T_L : light transmission in% according to illuminant D₆₅</li><li>external reflection (i.e. that measured on the external side, when the coated glass is mounted in monolithic glazing in a room with the stack of layers opposite 2: external reflection (R_LEXT) in%, a * (R_EXT), b * (R_EXT) the colorimetric coordinates in external reflection according to the colorimetry system (L *, a *, b *)</li><li>inner reflection: the value of R_LINT in%, and the color data a * (R_INT), b * (R_INT),</li><li>energy transmission: T_E in %</li></ul>

0044All these data are indicated twice: before heat treatment and after heat treatment. Are also measured in transmission ΔE * (T), in external reflection ΔE * (R_EXT) and in internal reflection ΔE * (R_INT), with ΔE * = (ΔL *² + Δa *² + Δb *²)^1/2 for transmission, with: <maths id="math0004"><math display="block"><mi mathvariant="normal">Δa</mi><mo mathvariant="normal">*</mo><mo mathvariant="normal">=</mo><mi mathvariant="normal">at</mi><mo mathvariant="normal">*</mo><mfenced><mi mathvariant="normal">after treatment</mi></mfenced><mo mathvariant="normal">-</mo><mi mathvariant="normal">at</mi><mo mathvariant="normal">*</mo><mfenced><mi>before treatment</mi></mfenced><mo mathvariant="normal">,</mo></math><img file="EP1919838B1_D0004.tif" /></maths><maths id="math0005"><math display="block"><mi mathvariant="normal">Δb</mi><mo mathvariant="normal">*</mo><mo mathvariant="normal">=</mo><mi mathvariant="normal">b</mi><mo mathvariant="normal">*</mo><mfenced><mi mathvariant="normal">after treatment</mi></mfenced><mo mathvariant="normal">-</mo><mi mathvariant="normal">b</mi><mo mathvariant="normal">*</mo><mfenced><mi>before treatment</mi></mfenced></math><img file="EP1919838B1_D0005.tif" /></maths><maths id="math0006"><math display="block"><mi mathvariant="normal">ΔL</mi><mo mathvariant="normal">*</mo><mo mathvariant="normal">=</mo><mi mathvariant="normal">L</mi><mo mathvariant="normal">*</mo><mfenced><mi mathvariant="normal">after treatment</mi></mfenced><mo mathvariant="normal">-</mo><mi mathvariant="normal">L</mi><mo mathvariant="normal">*</mo><mfenced><mi>before treatment</mi></mfenced></math><img file="EP1919838B1_D0006.tif" /></maths><tables id="tabl0001" num="0001"><table frame="all"><title><b><u>TABLE 1</u></b></title><tgroup cols="13"><colspec colnum="1" colname="col1" colwidth="21mm" /><colspec colnum="2" colname="col2" colwidth="38mm" /><colspec colnum="3" colname="col3" colwidth="14mm" /><colspec colnum="4" colname="col4" colwidth="18mm" /><colspec colnum="5" colname="col5" colwidth="18mm" /><colspec colnum="6" colname="col6" colwidth="14mm" /><colspec colnum="7" colname="col7" colwidth="12mm" /><colspec colnum="8" colname="col8" colwidth="11mm" /><colspec colnum="9" colname="col9" colwidth="11mm" /><colspec colnum="10" colname="col10" colwidth="13mm" /><colspec colnum="11" colname="col11" colwidth="12mm" /><colspec colnum="12" colname="col12" colwidth="17mm" /><colspec colnum="13" colname="col13" colwidth="16mm" /><thead><row><entry align="center" valign="middle"><b>EXAMPLE</b></entry><entry align="center" valign="middle"><b>Heat treatment</b></entry><entry namest="col3" nameend="col5" align="center" valign="middle"><b>TRANSMISSION</b></entry><entry namest="col6" nameend="col9" align="center" valign="middle"><b>EXTERNAL REFLECTION</b></entry><entry namest="col10" nameend="col13" align="center" valign="middle"><b>INTERNAL REFLECTION</b></entry></row><row><entry namest="col1" nameend="col2" align="center" valign="middle" /><entry align="center" valign="middle">T_L</entry><entry align="center" valign="middle">AT* _(REXT)</entry><entry align="center" valign="middle">b * _(REXT)</entry><entry align="center" valign="middle">R_LEXT</entry><entry align="center" valign="middle"><b>L</b>*</entry><entry align="center" valign="middle">at*</entry><entry align="center" valign="middle">b *</entry><entry align="center" valign="middle">R_LINT</entry><entry align="center" valign="middle"><b>L</b>*</entry><entry align="center" valign="middle">at* _(RINT)</entry><entry align="center" valign="middle">b *_(RINT)</entry></row></thead><tbody><row><entry morerows="1" valign="middle">Example 1</entry><entry valign="middle">Before</entry><entry align="center" valign="middle">66.7</entry><entry align="center" valign="middle">-1.2</entry><entry align="center" valign="middle">5.7</entry><entry align="center" valign="middle">31.4</entry><entry align="center" valign="middle">62.9</entry><entry align="center" valign="middle">-1.4</entry><entry align="center" valign="middle">-9.1</entry><entry align="center" valign="middle">29.8</entry><entry align="center" valign="middle">61.5</entry><entry align="center" valign="middle">-3.3</entry><entry align="center" valign="middle">-8.6</entry></row><row><entry valign="middle">After</entry><entry align="center" valign="middle">65.6</entry><entry align="center" valign="middle">-1</entry><entry align="center" valign="middle">6.3</entry><entry align="center" valign="middle">32.3</entry><entry align="center" valign="middle">63.6</entry><entry align="center" valign="middle">-1.3</entry><entry align="center" valign="middle">-9.9</entry><entry align="center" valign="middle">30.7</entry><entry align="center" valign="middle">62.3</entry><entry align="center" valign="middle">-3.2</entry><entry align="center" valign="middle">-9.4</entry></row><row><entry namest="col1" nameend="col2" align="left" valign="middle">ΔE *</entry><entry namest="col3" nameend="col5" align="center" valign="middle">1.2</entry><entry namest="col6" nameend="col9" align="center" valign="middle">1.2</entry><entry namest="col10" nameend="col13" align="center" valign="middle">1.2</entry></row><row><entry morerows="1" valign="middle">Example 2</entry><entry valign="middle">Before</entry><entry align="center" valign="middle">68.8</entry><entry align="center" valign="middle">-0.4</entry><entry align="center" valign="middle">4.4</entry><entry align="center" valign="middle">29.0</entry><entry align="center" valign="middle">60.8</entry><entry align="center" valign="middle">-2.3</entry><entry align="center" valign="middle">-7.4</entry><entry align="center" valign="middle">30.0</entry><entry align="center" valign="middle">61.7</entry><entry align="center" valign="middle">-1.3</entry><entry align="center" valign="middle">-7.5</entry></row><row><entry valign="middle">After</entry><entry align="center" valign="middle">67.6</entry><entry align="center" valign="middle">-0.3</entry><entry align="center" valign="middle">5.2</entry><entry align="center" valign="middle">30.1</entry><entry align="center" valign="middle">61.7</entry><entry align="center" valign="middle">-2.1</entry><entry align="center" valign="middle">-8.1</entry><entry align="center" valign="middle">31.1</entry><entry align="center" valign="middle">62.6</entry><entry align="center" valign="middle">-1.1</entry><entry align="center" valign="middle">-8.2</entry></row><row><entry namest="col1" nameend="col2" align="left" valign="middle">ΔE *</entry><entry namest="col3" nameend="col5" align="center" valign="middle">1.0</entry><entry namest="col6" nameend="col9" align="center" valign="middle">1.2</entry><entry namest="col10" nameend="col13" align="center" valign="middle">1.2</entry></row></tbody></tgroup></table></tables>

0045This table shows that Examples 1 and 2 according to the invention offer a good compromise ΔE * before heat treatment and after heat (little variation): they offer good sun protection. They are also good from an aesthetic point of view, especially in external reflection where the values ​​of a * and b * are negative, giving a color that is not very intense and in blue-green appreciated for glazing with strong external reflection.

0046What is notable is that all these advantages are retained after heat treatment: the values ​​of T_L and T_E are kept to within 1%, the colorimetric data change very little, there is no change from one shade to another shade in external reflection. There are no optical defects. The value of ΔE *, quantifying a possible colorimetric evolution, remains at most 1.2 in transmission, in internal and external reflection: it is indeed a stack capable of undergoing a treatment of bending or quenching type without significant degradation. Whether a tempered glass, annealed, curved or not, the invention provides an anti-solar stack with identical properties, preserved. The remarks made with regard to example 1 also apply to example 2, except with regard to the value of ΔE * in transmission which is appreciably lower than that corresponding for the reflection both inside and outside.

0047In conclusion, the sun protection glazings according to the invention are very advantageous for equipping buildings, without excluding applications in the automobile and all vehicles: the side windows, rear, the car roof, which may also have enamel coatings. With a fixed stack of layers, in particular according to the values ​​of T_L and T_E that we are looking for, we can thus, without having to modify it, manufacture glazing for vision which is not intended to undergo heat treatments or which must be curved / tempered / annealed, manufacture lighters in good colorimetric harmony with vision glazing, which can be lacquered or enameled: it is thus possible to standardize the production of interference layers on large substrates, which is a great advantage on an industrial level.

0048The invention has developed hardenable solar control glazing, with ΔE * in reflection and outside less than or equal to 1.2.

0049We can also make lighters with enameled layers, rather than lacquered, which is also industrially very interesting (the enameling is done during the quenching process while the lacquering requires an additional manufacturing step).