High-reflection glazing

The present invention relates to glazings which exhibit a high reflection in the visible range while retaining a significant part of transmission.

The glazing in question is useful in particular for limiting the natural energy supply, especially in buildings exposed to significant sunshine. Limiting energy intake saves the use of air conditioning. The glazings in question are also characterized by their “solar factor”, size designating the ratio of the energy both transmitted through the glazing and re-emitted by it towards the interior, after absorption, to the total incident energy.

Glazing of this type is most often formed by coating the glass sheet with a layer, or a system of so-called “hard” layers. These layers are traditionally deposited by pyrolysis on the hot glass immediately after formation of the sheet. The most usual is to carry out pyrolysis "online", that is to say on the very site of production of the glass. The glass ribbon formed on the “float” line is coated while it is still at high temperature.

A recognized characteristic of the products obtained by pyrolysis is that they are relatively hard. They are resistant to both chemical and mechanical attack. For this reason they are conveniently used, possibly exposing the coated side to external hazards. This feature distinguishes the layers obtained by pyrolysis from those produced by vacuum deposition techniques by sputtering, these two types of techniques constitute the two most widely used routes for the production of thin layers on a glass support.

In contrast, the layers obtained by sputtering under vacuum are said to be “soft”. Their insufficient mechanical or chemical resistance means that these layers are mainly used in configurations where they are not exposed to these attacks. This is the case in multiple glazing. In these glazings the layers are turned towards the spaces located between the sheets.

While the use of pyrolytic layers is technically satisfactory, it is however closely linked to the availability of suitable specific precursors. The available precursors do not make it possible to produce all of the accessible layers. Furthermore, the implementation of pyrolysis techniques requires the presence of very heavy specific installations which must be integrated into the production lines which, by nature and for the sake of economy of scale, are necessarily in limited numbers and therefore geographically discreetly distributed in the territories for which these products are intended.

The installations for coating by sputtering under vacuum are independent of that for manufacturing glass. The coating operations by these techniques are carried out "in recovery" according to the usual terminology, in other words on glass which has been manufactured previously and which in the meantime may have been stored, transported, re-cut etc.

For logistical reasons in particular, the possibility of providing glazing coated by cathode sputtering offering the qualities of the products obtained by pyrolysis is an object of the invention. It is obviously necessary that the production cost of these glazings remains comparable to that of glazings coated by pyrolysis.

Fr 2793889 describes glazing comprising for example a layer of doped titanium oxide obtained by sputtering. Layers deposited by sputtering under vacuum and which lead to interesting solar factors are known. This is particularly the case with titanium oxide layers. These layers however show, as indicated above, an insufficient mechanical strength to be able to be used outside the unexposed faces of the glazing considered.

The inventors have shown that a very specific choice of the materials constituting these layers deposited by sputtering makes it possible to achieve the resistance requirements indicated.

The inventors have also shown that by an appropriate choice of layers or layer systems produced, it is also possible to subject the glazings in question to vigorous subsequent heat treatments, such as bending or tempering treatments without altering the characteristics. essentials conferred by these layers.

The layers or layer systems considered according to the invention do not contain a metal type layer reflecting infrared, in particular silver-based layers, the systems comprising these silver-based layers systematically showing a certain fragility to attack. outside.

The object of the invention is to provide glazing units which meet the requirements set out above.

The inventors have shown that this object can be achieved by glazings as defined in claim 1. It is remarkable that the layers comprising titanium oxide associated with other oxides make it possible to achieve the desired characteristics, in particular of resistance , while layers of titanium oxide alone, as indicated above, are insufficiently resistant.

The reasons for the quality of the layers used according to the invention are not fully understood. It is likely that the fact of depositing a layer composed of titanium oxide with another oxide leads to a modification of the structure of the layer. The crystal formation is certainly modified. The presence of two or more constituents, whose crystallographic characteristics are not the same, leads to a very specific growth, probably by avoiding in particular the formation of more fragile structures like the columns.

A certain variety of oxides is likely to be associated with titanium oxide in this layer. Among the oxides which can be used are those of the following compounds: Al, Zr, Hf, V, Mn, Fe, Co, Ni, Cu, Si. Among these preferred oxides are especially those of Al, Zr, Hf, and very particularly Zr oxide.

Particularly advantageously, the zirconium oxide included in the layer based on titanium oxide is present in an amount of 25 to 60% by weight and preferably from 40 to 55%. Zirconium oxide is particularly advantageous insofar as, in addition to imparting the desired resistance properties, its refractive index being close to that of titanium oxide, the optical properties of coated glazings, and in particular the reflection, are also close to those observed with a layer of titanium oxide.

The resistance of the titanium oxide-based layer depends on its composition, it also depends on its thickness. If an increase in thickness is accompanied by increased resistance, beyond a certain threshold the improvement is not significant, the additional cost for a thicker deposit becomes unnecessary. The titanium oxide-based layer according to the invention has a thickness of between 15.0 and 90.0 nm, preferably between 20.0 and 50.0 nm, and advantageously from 25.0 to 35.0 nm . The choice of the thickness of the titanium oxide-based layer also depends on the presence of other layers, but also on the qualities sought in terms of reflection, transmission and absorption of the incident light. For the glazings according to the invention, the reflection which is generally at least 15% when the layer or the layer system is applied to clear glass 4 mm thick, is advantageously under the same conditions between 20 and 40%.

The thickness of the titanium oxide-based layer, or of the layer system in which it is included, in particular its index, determines the reflection obtained but also the other optical quantities, in particular the light transmission. For the glazings according to the invention the light transmission being at least 60%. The light absorbed by the glazing remains relatively low. It is advantageously less than 20% and preferably less than 10%.

In the glazings according to the invention, the layer based on titanium oxide can be combined with other layers in order to improve the properties thereof or to confer properties which the layer based on titanium oxide would not exhibit or not have. degree appropriate to the intended use.

The protection conferred by the layer based on titanium oxide does not necessarily imply that the reflection comes exclusively from this layer. Once the necessary resistance has been obtained, the layer system can include other layers, in particular to contribute to reflection. In this perspective, a layer with high reflection and therefore with a high index can be associated with the layer based on titanium oxide and on another oxide. Most conveniently this or these additional layers must also have a high reflection index, a particularly preferred layer is a layer of titanium oxide. This layer has the particularity, compared to layers based on titanium oxide, of having a higher refractive index. By way of indication, the layers comprising in association of titanium and zirconium oxide (50/50% by weight) deposited under vacuum have an index of the order of 2.35. TiO layers₂, stoichiometric or not, the latter usually denoted TXO, layers which can be obtained in particular by using ceramic cathodes, have an index of the order of 2.45-2.50. The combination of a TiO layer₂ or TXO, with a layer of alloy based on titanium oxide therefore makes it possible, if necessary, to simultaneously benefit from a good resistance imparted by this last layer, and overall a higher index.

The use of the glazing units according to the invention can take place without any other modification than the setting to the desired dimensions and introduction into frames. The glazing in question in this case is essentially flat. The need for scaling after coating means that the glass sheets used in the composition of these glazings are not subjected to a heat treatment beforehand. The heat treatments in question by ensuring the presence of stresses, give the glazing mechanical properties ensuring both better impact resistance and above all, in the event of a violent shock, these glazing break into multiple fragments of small dimensions.

When it is desired to have glazing which is curved or tempered, it is necessary to go through a heat treatment at high temperature after the application of layers. These treatments lead the glazing to temperatures which exceed 550 ° C. and often 600 ° C., and this for a more or less long time. In the case of bending or bending, the transformation may thus require maintaining these temperatures for several minutes taking into account in particular the thermal inertia of the glass. The holding time at these temperatures can reach 5 minutes or more depending on the techniques used and the thickness of the treated sheets.

Heat treatments of the quenching or bending type are known to be capable of altering the thin layers deposited on the glass sheets. Independently of the alterations which may appear in the structure of certain layers due to the very temperature, the glass substrate can also induce undesirable modifications.

Overall, the titanium oxide-based layers considered according to the invention do not undergo a detrimental change in structure under the conditions of these heat treatments. The structure of the layers remains substantially unchanged. However, glass sheets of the soda-lime-silica type, in other words the most common glasses, subjected to high temperatures can lead to deterioration of the layers with which they are coated. At the temperatures considered, the alkaline constituents of these glasses are liable to migrate and diffuse in the layers in contact with the glass. The diffusion of these mobile elements often leads to the appearance of a more or less pronounced haze.

The appearance of the veil corresponds to a light scattering mechanism due to the presence of elements foreign to the structure of the layer.

In practice, the products used must be very transparent. The proportion of scattered light in relation to the transmitted light should not exceed 2% and preferably not 1%. These limits can be exceeded if no precaution is taken to protect the layers of the type based on titanium oxide used according to the invention.

To prevent the phenomena of diffusion, in particular that of the alkaline ions of the glass in the layers, it is known to have layers which oppose the passage of these ions, layers which are interposed between the substrate and the layer to be protected. Protective layers of this type are especially the SiO layers₂. If their barrier quality is well known, their production by sputtering remains relatively expensive. Since it is desirable to deposit all of the layers in the same way and in a single pass, it may be preferable to replace the silica layers with layers having similar properties but easier to produce.

According to the invention, as a layer preventing the diffusion of the constituents of the substrate in the layer based on modified titanium oxide, it is proposed to use either a layer of SiO₂, either at least one layer based on tin oxide or another layer of silicon nitride Si₃NOT₄.

When a layer based on tin oxide is used, it comprises at least 30% and preferably at least 40% by weight of tin oxide.

The tin oxide-based layer also preferably comprises zinc oxide. The combination of these two oxides offers the advantage, in addition to a high deposition rate by sputtering techniques, of leading to layers whose structure is very stable in the heat treatments considered.

Zinc oxide alone is not desirable as a layer preventing diffusion due to its tendency to form columnar structures, in particular when its thickness exceeds ten nanometers. These structures are not very effective against diffusion phenomena.

The combination of zinc and tin oxides prevents the formation of columnar structures as long as the content of tin oxide remains sufficient.

The presence of a layer preventing the diffusion of the constituents of the glass modifies the optical properties of the glazing. In particular, the presence of a layer based on tin oxide, the refractive index of which is lower than that of the layer based on titanium oxide, modifies the reflection.

In order not to excessively reduce the reflection of the glazing, it is preferable to make sure, when a layer based on tin oxide is used, to properly adjust its thickness. This is preferably less than 1.2 times the thickness of the layer based on titanium oxide.

The layers or layer systems used according to the invention must also lead to glazing whose coloration induced by these layers meets market demand. Certain colors, especially in reflection, must be discarded. This is particularly the case for overall "purple" colorings. These colors appear when analyzed in the CIE system (International Lighting Committee) the parameters a * and b * meet the following conditions: for an illuminant D and for a solid angle of 10 ° at most a * ≤0 and b * ≤6. It is particularly important to systematically have a * non positive. For negative values ​​of a * the coloring is either slightly blue or slightly green. These reflective stains are acceptable even if the preference is color neutrality.

It is also preferable, in the case of a heat treatment, that this does not cause a significant modification of the coloring in reflection. When the products offer substantially the same colorings, it is possible to use in the same set of products, for example domed and others which are not, without difference in appearance. The products can be juxtaposed without affecting the aesthetics.

In practice, the more "neutral" the products, the more their coloring, before and after heat treatment, allows them to be juxtaposed.

In practice, glazings which meet these coloring requirements preferably have, before and after heat treatment, variations of a * and b * such as ΔE * ≤ 2 and advantageously ΔE * ≤ 1, with: <maths id="math0001" num=""><math display="block"><mi>ΔE</mi><mo>*</mo><mo>=</mo><msup><mfenced><mrow><mi>Δa</mi><msup><mo>*</mo><mn>2</mn></msup><mo>+</mo><mi>Δb</mi><msup><mo>*</mo><mn>2</mn></msup></mrow></mfenced><mn>½</mn></msup></math><img file="EP2331475B1_D0001.tif" /></maths>

Apart from the layers which determine the optical characteristics of the glazings according to the invention, and with the aim of further protecting these layers against the risks of deterioration in subsequent operations, in particular storage and transport, it is possible and advantageous to cover these layers by a temporary coating which is removed before the installation of these glazings.

It is known to cover glazing with films of various soluble waxes or polymers which can be removed by washing. These products can be used to protect the layers used according to the invention.

The use of these protective products requires two additional operations on the glazing, the application on the one hand and the subsequent washing on the other hand. In the case of glazing to be heat treated, it is preferable to use a carbon coating, which can be integrated into the sputtering deposition operations, and the elimination of which takes place by itself during the heat treatment by combustion in contact with air.

The glazings according to the invention are made from glass sheets of different thicknesses. They can also consist of sheets of clear or colored glass in the mass, mainly to give them aesthetic characteristics, but also possibly to adjust their opto-energetic properties.

It is possible to use glasses that are more absorbent than clear glasses, especially gray glasses or glasses with a slight blue or green dominant. Preferably when colored glasses are used, the dominant wavelength in reflection λ_m, for a D65 illuminant in a solid angle of 2 °, is between 475 and 600nm.

The invention is described in detail below by examples of implementation of the invention, where appropriate with reference to the accompanying drawings in which the <figref idref="f0001">Figures 1 to 3</figref> are schematic representations of glazing according to the invention.<ul id="ul0001" list-style="none"><li>The <figref idref="f0001">figure 1</figref> shows a glazing 1 comprising a layer based on titanium oxide 2. The respective thicknesses are not respected for clarity.</li><li>The <figref idref="f0001">figure 2</figref> is a glazing according to the invention which, in addition to the layer based on titanium oxide 2, comprises a layer 3 whose role is to obstruct the diffusion of constituents of the glass sheet 1.</li><li>The <figref idref="f0001">figure 3</figref> represents a glazing according to the invention which, in addition to the preceding layers, comprises a protective coating 4. The coating in question which is applied on a temporary basis, has the essential role of preventing scratches, scratches and other mechanical alterations liable to reach functional layers 3. This layer in the case of glazing undergoing a heat treatment after the formation of the functional layers, advantageously consists of a material which is eliminated by combustion during this heat treatment. A carbon layer is particularly advantageous for constituting this coating.</li></ul>

The products according to the invention are analyzed in particular for their qualities of mechanical or chemical resistance. The tests to which they are subjected are the same as those used for the evaluation of similar glazings whose functional layers are produced by pyrolysis. The glazings according to the invention must achieve equivalent performance.

The tests systematically include humidity resistance tests (21 days in a climatic chamber), chemical resistance tests (neutral salt spray of 21 days and exposure to SO₂ five cycles), an abrasion resistance test (AWRT for Automatic Web Rub Test) and scratch resistance (DBT for Dry Brush Test). The chemical resistance tests are those described in the draft standard prEN 1096-2. The abrasion tests are specific to the tests of the layers deposited by "magnetron sputtering". These two tests are appreciably more "severe" than the analogous tests described in the standard indicated above. In other words, the abrasion tests passed in the examples carried out, are necessarily satisfactory under the conditions of this standard.

The climatic chamber test consists in exposing the sample in an oven maintained at 40 ± 1.5 ° C for 21 days. The test is passed when the sample remains free of stains. Aging under these conditions for each day corresponds to a one-year exposure to the usual atmospheric hazards.

The sample must not be discolored, nor generally endure defects of any kind, such as peeling of the layer.

The acid atmosphere resistance test is carried out as follows: The sample is placed in an enclosure charged with an acid atmosphere (two liters of water for 2 liters of SO₂) brought to 40 ° C for 8 hours. Returned to room temperature, the sample remains another 16 hours in the atmosphere in question. The same cycle is repeated 4 times. The diaper should not come off.

The "AWRT" wet friction test (automatic wet rub test) is carried out with a circular teflon head covered with a cotton fabric (ADSOL ref. 40700004). This is moved under a load of 1050g on the layer. The cotton is kept moist throughout the test with demineralized water. The frequency of the oscillations is 60 to 90 per minute. The samples are observed to detect alterations to the layer.

The “dry brush test” test is carried out on an Erichsen apparatus (model 494) equipped with a standardized brush (ASTM D2486). Each fiber of the brush has a diameter of 0.3mm. The fibers are grouped together in a 4mm diameter bundle. The total weight applied by the brush and its support is 454g. The test includes 1000 cycles of back and forth.

The measurements of the optical quantities are made according to standard EN410.

The samples are made on sheets of clear float glass 4mm thick.

Example 1.

A layer of titanium oxide is deposited comprising 12% of aluminum atoms relative to all of the metal atoms. The thickness of the layer is 572Â.

The chemical and mechanical resistance tests are satisfactory. The optical properties of the sample are in transmission, reflection (under 2 °) and for colorimetric data (illuminating D65 under 10 °) in transmission and reflection:<tables id="tabl0001" num="0001"><table frame="all"><tgroup cols="6"><colspec colnum="1" colname="col1" colwidth="12mm" /><colspec colnum="2" colname="col2" colwidth="12mm" /><colspec colnum="3" colname="col3" colwidth="17mm" /><colspec colnum="4" colname="col4" colwidth="17mm" /><colspec colnum="5" colname="col5" colwidth="14mm" /><colspec colnum="6" colname="col6" colwidth="14mm" /><thead><row><entry valign="top">TL</entry><entry valign="top">R</entry><entry valign="top">a * trans.</entry><entry valign="top">b * trans.</entry><entry valign="top">a * ref.</entry><entry valign="top">in short.</entry></row></thead><tbody><row><entry>71,1</entry><entry>26,9</entry><entry>0,3</entry><entry>-0,3</entry><entry>-3,1</entry><entry>1,2</entry></row></tbody></tgroup></table></tables>

Examples 2, 3 and 4 and 2 ', 3', 4 '.

The samples of Examples 2 and 3 comprise a layer of titanium oxide at 50% by weight, the remaining 50% being zirconium oxide. In example 2 the layer has a thickness of 300Â. For example 3 the layer is 600Â.

Sample 4 comprises on the glass a first layer of 50% by weight tin oxide and 50% by weight zinc oxide. In this case the two layers each have a thickness of 300Â.

The samples 2 ', 3', 4 'are of identical structure to the previous ones. They underwent a heat treatment at 670 ° C for 8 minutes 30.

All samples without heat treatment pass chemical tests. The abrasion resistance is satisfied for samples 3 and 4.

Samples 2 'have a haze slightly above the limit of what is considered acceptable. The 3 'samples, of the same nature but whose layer is a little thicker, are a little better with regard to the formation of haze in the acid tests which prove to be the most severe.

The 3 'and especially 4' samples successfully withstand abrasion tests.

The optical properties of these samples are reported in the following table:<tables id="tabl0002" num="0002"><table frame="all"><tgroup cols="8"><colspec colnum="1" colname="col1" colwidth="8mm" /><colspec colnum="2" colname="col2" colwidth="14mm" /><colspec colnum="3" colname="col3" colwidth="14mm" /><colspec colnum="4" colname="col4" colwidth="17mm" /><colspec colnum="5" colname="col5" colwidth="17mm" /><colspec colnum="6" colname="col6" colwidth="14mm" /><colspec colnum="7" colname="col7" colwidth="14mm" /><colspec colnum="8" colname="col8" colwidth="15mm" /><thead><row><entry valign="top" /><entry valign="top">TL</entry><entry valign="top">R</entry><entry valign="top">a * trans.</entry><entry valign="top">b * trans.</entry><entry valign="top">a * ref.</entry><entry valign="top">in short.</entry><entry valign="top">ΔE * ref</entry></row></thead><tbody><row><entry>2</entry><entry>75,93</entry><entry>21,04</entry><entry>- 1,0</entry><entry>5,05</entry><entry>- 1,41</entry><entry>- 9,59</entry><entry /></row><row><entry>2'</entry><entry>75,44</entry><entry>21,33</entry><entry>- 0,99</entry><entry>5,14</entry><entry>- 1,54</entry><entry>- 9,32</entry><entry>0,43</entry></row><row><entry>3</entry><entry>64,88</entry><entry>32,16</entry><entry>- 0,05</entry><entry>0,98</entry><entry>- 2,22</entry><entry>- 0,81</entry><entry /></row><row><entry>3'</entry><entry>64,58</entry><entry>32,27</entry><entry>- 0,09</entry><entry>0,70</entry><entry>- 2,25</entry><entry>- 0,21</entry><entry>0,60</entry></row><row><entry>4</entry><entry>69,48</entry><entry>27,54</entry><entry>- 0,45</entry><entry>1,37</entry><entry>- 2,13</entry><entry>- 1,25</entry><entry /></row><row><entry>4'</entry><entry>70,41</entry><entry>26,06</entry><entry>- 0,58</entry><entry>1,51</entry><entry>- 2,00</entry><entry>- 1,74</entry><entry>1,45</entry></row></tbody></tgroup></table></tables>

Examples 5 to 12 and 5 'to 12'.

Different layer systems comprising a tin oxide layer and a zinc oxide layer are tested under the above conditions.

The composition of the layer systems used and their thicknesses in Å are reported in the following table in which:<ul id="ul0002" list-style="dash" compact="compact"><li>TZO indicates a layer of titanium oxide at 50% by weight of zirconium oxide;</li><li>ZSO5 indicates a layer of tin oxide at 50% by weight of zinc oxide;</li><li>TCrO indicates a layer of titanium oxide at 8% by weight of chromium oxide;</li><li>SnO₂ indicates a layer of tin oxide without other oxide</li></ul>

Examples 10 to 12 and 10 'to 12' are not according to the invention.<tables id="tabl0003" num="0003"><table frame="all"><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="9mm" /><colspec colnum="2" colname="col2" colwidth="14mm" /><colspec colnum="3" colname="col3" colwidth="14mm" /><colspec colnum="4" colname="col4" colwidth="12mm" /><colspec colnum="5" colname="col5" colwidth="14mm" /><thead><row><entry valign="top" /><entry valign="top">ZSO5</entry><entry valign="top">SnO₂</entry><entry valign="top">TZO</entry><entry valign="top">TCrO</entry></row></thead><tbody><row><entry>5</entry><entry>300</entry><entry /><entry>300</entry><entry /></row><row><entry>6</entry><entry>250</entry><entry /><entry>250</entry><entry /></row><row><entry>7</entry><entry /><entry>300</entry><entry>300</entry><entry /></row><row><entry>8</entry><entry /><entry>250</entry><entry>250</entry><entry /></row><row><entry>9</entry><entry /><entry>200</entry><entry>200</entry><entry /></row><row><entry>10</entry><entry /><entry>300</entry><entry /><entry>300</entry></row><row><entry>11</entry><entry /><entry>250</entry><entry /><entry>250</entry></row><row><entry>12</entry><entry>250</entry><entry /><entry /><entry>250</entry></row></tbody></tgroup></table></tables>

The abrasion test samples all achieved a score of 4 which is acceptable.

Subject to the heat treatment previously used (670 ° C, for 8 minutes 30), they lead to the optical properties gathered in the following table in which g is the solar factor.<tables id="tabl0004" num="0004"><table frame="all"><tgroup cols="9"><colspec colnum="1" colname="col1" colwidth="10mm" /><colspec colnum="2" colname="col2" colwidth="12mm" /><colspec colnum="3" colname="col3" colwidth="12mm" /><colspec colnum="4" colname="col4" colwidth="12mm" /><colspec colnum="5" colname="col5" colwidth="15mm" /><colspec colnum="6" colname="col6" colwidth="17mm" /><colspec colnum="7" colname="col7" colwidth="17mm" /><colspec colnum="8" colname="col8" colwidth="14mm" /><colspec colnum="9" colname="col9" colwidth="14mm" /><thead><row><entry valign="top" /><entry valign="top">TL</entry><entry valign="top">R</entry><entry valign="top">g</entry><entry valign="top">Selec.</entry><entry valign="top">a * trans.</entry><entry valign="top">b * trans.</entry><entry valign="top">a * ref.</entry><entry valign="top">in short.</entry></row></thead><tbody><row><entry>5'</entry><entry>70,9</entry><entry>26,2</entry><entry>71,8</entry><entry>0,99</entry><entry>- 0,2</entry><entry>4,5</entry><entry>- 1,8</entry><entry>- 5,8</entry></row><row><entry>6'</entry><entry>74,7</entry><entry>23,1</entry><entry>74,3</entry><entry>1,01</entry><entry>- 0,5</entry><entry>4,3</entry><entry>- 1,5</entry><entry>- 7,8</entry></row><row><entry>7'</entry><entry>68,8</entry><entry>29,7</entry><entry>70,1</entry><entry>0,98</entry><entry>0</entry><entry>3,4</entry><entry>- 2</entry><entry>- 5,2</entry></row><row><entry>8'</entry><entry>68,8</entry><entry>26,3</entry><entry>70,8</entry><entry>0,97</entry><entry>0,5</entry><entry>7,4</entry><entry>- 1,8</entry><entry>- 7,9</entry></row><row><entry>9'</entry><entry>73,8</entry><entry>22,8</entry><entry>73,8</entry><entry>1</entry><entry>- 0,3</entry><entry>6,1</entry><entry>- 1,5</entry><entry>- 9,2</entry></row><row><entry>10'</entry><entry>71,4</entry><entry>26,6</entry><entry>71,7</entry><entry>1</entry><entry>- 0,4</entry><entry>6,9</entry><entry>- 1,9</entry><entry>- 9,4</entry></row><row><entry>11'</entry><entry>72,1</entry><entry>25,7</entry><entry>72,2</entry><entry>1</entry><entry>- 0,5</entry><entry>6,5</entry><entry>- 2</entry><entry>- 8,9</entry></row><row><entry>12'</entry><entry>7-,8</entry><entry>20</entry><entry>75,8</entry><entry>1,01</entry><entry>- 0,7</entry><entry>4,9</entry><entry>- 0,5</entry><entry>- 6,8</entry></row></tbody></tgroup></table></tables>

Examples 13 to 15.

For these examples we use a layer of SiO₂ in protection against diffusion. The thicknesses of the SiO layers₂ and of titanium oxide comprising 50% of zirconium oxide are the are expressed in Å. The table also includes the reflection values ​​and the variations in reflection and the values ​​a * and b * after the glazing has been subjected to the heat treatment indicated above:<tables id="tabl0005" num="0005"><table frame="all"><tgroup cols="7"><colspec colnum="1" colname="col1" colwidth="9mm" /><colspec colnum="2" colname="col2" colwidth="12mm" /><colspec colnum="3" colname="col3" colwidth="12mm" /><colspec colnum="4" colname="col4" colwidth="14mm" /><colspec colnum="5" colname="col5" colwidth="14mm" /><colspec colnum="6" colname="col6" colwidth="14mm" /><colspec colnum="7" colname="col7" colwidth="14mm" /><thead><row><entry align="center" valign="top" /><entry align="center" valign="top">SiO₂</entry><entry align="center" valign="top">TZO</entry><entry align="center" valign="top">R</entry><entry align="center" valign="top">ΔR</entry><entry align="center" valign="top">Δa *</entry><entry align="center" valign="top">Δb *</entry></row></thead><tbody><row><entry align="center">13</entry><entry align="center">100</entry><entry align="center">500</entry><entry align="center">29,49</entry><entry align="center">0,03</entry><entry align="center">- 0,01</entry><entry align="center">- 0,11</entry></row><row><entry align="center">14</entry><entry align="center">300</entry><entry align="center">500</entry><entry align="center">29,4</entry><entry align="center">0,05</entry><entry align="center">- 0,04</entry><entry align="center">- 0,31</entry></row><row><entry align="center">15</entry><entry align="center">170</entry><entry align="center">380</entry><entry align="center">24,64</entry><entry align="center">- 0,02</entry><entry align="center">- 0,08</entry><entry align="center">0</entry></row></tbody></tgroup></table></tables>

The modifications of the properties following the heat treatment remain very limited.

The samples also pass tests for resistance to humidity, salt spray, the climatic chamber and abrasion. Examples 16 to 19.

The examples relate to glazings in which the modified titanium oxide layer is associated with a diffusion-preventing layer composed of silicon nitride. Results similar to the previous ones are also shown in the table.<tables id="tabl0006" num="0006"><table frame="all"><tgroup cols="7"><colspec colnum="1" colname="col1" colwidth="9mm" /><colspec colnum="2" colname="col2" colwidth="14mm" /><colspec colnum="3" colname="col3" colwidth="12mm" /><colspec colnum="4" colname="col4" colwidth="14mm" /><colspec colnum="5" colname="col5" colwidth="14mm" /><colspec colnum="6" colname="col6" colwidth="14mm" /><colspec colnum="7" colname="col7" colwidth="14mm" /><thead><row><entry align="center" valign="top" /><entry align="center" valign="top">Yes₃NOT₄</entry><entry align="center" valign="top">TZO</entry><entry align="center" valign="top">R</entry><entry align="center" valign="top">ΔR</entry><entry align="center" valign="top">Δa *</entry><entry align="center" valign="top">Δb *</entry></row></thead><tbody><row><entry align="center">16</entry><entry align="center">100</entry><entry align="center">500</entry><entry align="center">29,94</entry><entry align="center">0,05</entry><entry align="center">0</entry><entry align="center">- 2,03</entry></row><row><entry align="center">17</entry><entry align="center">250</entry><entry align="center">250</entry><entry align="center">24,48</entry><entry align="center">- 0,98</entry><entry align="center">- 0,04</entry><entry align="center">- 0,29</entry></row><row><entry align="center">18</entry><entry align="center">300</entry><entry align="center">500</entry><entry align="center">28,06</entry><entry align="center">0,46</entry><entry align="center">- 0,11</entry><entry align="center">- 2,1</entry></row><row><entry align="center">19</entry><entry align="center">300</entry><entry align="center">200</entry><entry align="center">23,37</entry><entry align="center">- 1,01</entry><entry align="center">0,07</entry><entry align="center">- 0,26</entry></row></tbody></tgroup></table></tables>

As before, the variations caused by the heat treatment remain limited and the mechanical and chemical resistances meet practical requirements.

Examples 20 to 22 (outside the invention).

For these examples the TiO-based layer₂ (TNO) is modified by niobium oxide (50% by weight). The anti-diffusion layer is tin oxide. Results similar to the previous ones are also shown in the table.<tables id="tabl0007" num="0007"><table frame="all"><tgroup cols="7"><colspec colnum="1" colname="col1" colwidth="9mm" /><colspec colnum="2" colname="col2" colwidth="14mm" /><colspec colnum="3" colname="col3" colwidth="12mm" /><colspec colnum="4" colname="col4" colwidth="12mm" /><colspec colnum="5" colname="col5" colwidth="12mm" /><colspec colnum="6" colname="col6" colwidth="12mm" /><colspec colnum="7" colname="col7" colwidth="12mm" /><thead><row><entry align="center" valign="top" /><entry align="center" valign="top">SnO₂</entry><entry align="center" valign="top">TNO</entry><entry align="center" valign="top">R</entry><entry align="center" valign="top">ΔR</entry><entry align="center" valign="top">Δa *</entry><entry align="center" valign="top">Δb *</entry></row></thead><tbody><row><entry align="center">20</entry><entry align="center">300</entry><entry align="center">300</entry><entry align="center">30,0</entry><entry align="center">- 1,1</entry><entry align="center">- 1,4</entry><entry align="center">- 1,4</entry></row><row><entry align="center">21</entry><entry align="center">400</entry><entry align="center">200</entry><entry align="center">28,1</entry><entry align="center">- 0,5</entry><entry align="center">- 2,1</entry><entry align="center">- 2,1</entry></row><row><entry align="center">22</entry><entry align="center">400</entry><entry align="center">400</entry><entry align="center">29,6</entry><entry align="center">0</entry><entry align="center">- 3,6</entry><entry align="center">- 3,6</entry></row></tbody></tgroup></table></tables>

As before, the samples have good mechanical and chemical resistance.

Examples 23 to 29.

The examples are all carried out with several layers conferring the reflective properties. A layer of titanium oxide is associated with the layer which provides chemical and mechanical resistance. For examples 23 and 24 the upper layer (TZO) is based on titanium and zirconium oxide (50% by weight). Examples 25 to 29, outside the invention, have for top layer (TNO) a layer comprising niobium oxide (50% by weight).

The results obtained are as follows:<tables id="tabl0008" num="0008"><table frame="all"><tgroup cols="7"><colspec colnum="1" colname="col1" colwidth="9mm" /><colspec colnum="2" colname="col2" colwidth="12mm" /><colspec colnum="3" colname="col3" colwidth="20mm" /><colspec colnum="4" colname="col4" colwidth="12mm" /><colspec colnum="5" colname="col5" colwidth="12mm" /><colspec colnum="6" colname="col6" colwidth="12mm" /><colspec colnum="7" colname="col7" colwidth="12mm" /><thead><row><entry align="center" valign="top" /><entry align="center" valign="top">TiO₂</entry><entry align="center" valign="top">TZO / TNO</entry><entry align="center" valign="top">R</entry><entry align="center" valign="top">ΔR</entry><entry align="center" valign="top">Δa *</entry><entry align="center" valign="top">Δb *</entry></row></thead><tbody><row><entry align="center">23</entry><entry align="center">200</entry><entry align="center">300</entry><entry align="center">32,4</entry><entry align="center">- 2,5</entry><entry align="center">1,0</entry><entry align="center">1,0</entry></row><row><entry align="center">24</entry><entry align="center">400</entry><entry align="center">400</entry><entry align="center">29,5</entry><entry align="center">0,8</entry><entry align="center">0</entry><entry align="center">0</entry></row><row><entry align="center">25</entry><entry align="center">300</entry><entry align="center">300</entry><entry align="center">34,6</entry><entry align="center">- 2,1</entry><entry align="center">2,3</entry><entry align="center">2,3</entry></row><row><entry align="center">26</entry><entry align="center">200</entry><entry align="center">200</entry><entry align="center">30,7</entry><entry align="center">- 2,4</entry><entry align="center">1,6</entry><entry align="center">1,6</entry></row><row><entry align="center">27</entry><entry align="center">300</entry><entry align="center">250</entry><entry align="center">34,3</entry><entry align="center">- 1,2</entry><entry align="center">1,4</entry><entry align="center">1,4</entry></row><row><entry align="center">28</entry><entry align="center">300</entry><entry align="center">350</entry><entry align="center">33,6</entry><entry align="center">0,6</entry><entry align="center">- 0,3</entry><entry align="center">- 0,3</entry></row><row><entry align="center">29</entry><entry align="center">300</entry><entry align="center">350</entry><entry align="center">34,3</entry><entry align="center">- 2,4</entry><entry align="center">2,8</entry><entry align="center">2,8</entry></row></tbody></tgroup></table></tables>

The superposition of high index layers leads to an increase in overall reflection. The mechanical and chemical qualities are satisfactory.

Examples 30 to 32.

All these examples are produced using a system of reflective layers, including a layer of titanium oxide deposited from a ceramic target (TXO). The upper layers are of an alloy of titanium oxide and zirconium oxide at 50% by weight (30), or at 25% of zirconium oxide (31), again with a layer similar to the previous one topped a layer of a triple alloy of titanium oxide of zirconium and silicon (respectively 45/45/6% by weight, the target still contains yttrium oxide with no particular function) designated TZSO (32) .<tables id="tabl0009" num="0009"><table frame="all"><tgroup cols="7"><colspec colnum="1" colname="col1" colwidth="9mm" /><colspec colnum="2" colname="col2" colwidth="12mm" /><colspec colnum="3" colname="col3" colwidth="22mm" /><colspec colnum="4" colname="col4" colwidth="14mm" /><colspec colnum="5" colname="col5" colwidth="14mm" /><colspec colnum="6" colname="col6" colwidth="14mm" /><colspec colnum="7" colname="col7" colwidth="14mm" /><thead><row><entry align="center" valign="top" /><entry align="center" valign="top">TXO</entry><entry align="center" valign="top">TZO (TZSO)</entry><entry align="center" valign="top">R</entry><entry align="center" valign="top">ΔR</entry><entry align="center" valign="top">Δa *</entry><entry align="center" valign="top">Δb *</entry></row></thead><tbody><row><entry align="center">30</entry><entry align="center">350</entry><entry align="center">100</entry><entry align="center">30,96</entry><entry align="center">3,16</entry><entry align="center">- 0,14</entry><entry align="center">2,52</entry></row><row><entry align="center">31</entry><entry align="center">107</entry><entry align="center">352</entry><entry align="center">28,38</entry><entry align="center">- 1,03</entry><entry align="center">- 0,13</entry><entry align="center">- 0,31</entry></row><row><entry align="center">32</entry><entry align="center">107</entry><entry align="center">352+100</entry><entry align="center">29,98</entry><entry align="center">- 0,19</entry><entry align="center">0,15</entry><entry align="center">- 0,35</entry></row></tbody></tgroup></table></tables>

The role of the TXO layer on reflection is again well illustrated. Even for similar total thicknesses, Example 30 comprising the thickest TXO layer is more reflective than Example 31. The addition of the TSZO layer also increases the reflection of Example 32 compared to that of example 30.