Process for making a tempered and/or curved glass plate with a reduced transmission

The invention relates to a method for producing a biased and / or curved glass pane of soda Lime silicate glass with reduced transmission in (a) definable spectral region (s), in particular sunscreen disc in which at least one side of a glass support is at least a metal layer with a überwie ing from content to a metal or metal alloy the elements having the atomic numbers 22 to 28 of the Perio Indian system and remote on the glass carrier Side a protective layer of at least one metal oxide or Mixed metal oxide are deposited and a thermal Toughening and / or bending process in air at a Tem temperature of 580 ° C to 680 ° C, preferably 600 ° C to 650 ° C, is performed.

Glass panes, which superficially a coating of a metal or a metal alloy and subsequently thereon a protective layer of a metal oxide or metal mixed oxide have, be in the construction sector and in the Vehicle glazing used to the transmission of un coated glass substrate in specific spectral regions to reduce. This is done for. Example, a light attenuation effect and / or to obtain a sunscreen effect, wherein the metal layer preferably metals or metals Governments from the elements with atomic numbers 22-28 of the Periodic Table are used when color-neutral Glass panes are desired. In many such application cases it is necessary to thermally vorzu the glass support tighten. This happens, for. Example, to increase the mechanical Stability, to avoid thermal breakage and Redu cation of the injury risk in wheel breakage.

For the generation of thermal prestressing will be the almost exclusively used in said application Slices of soda lime silicate glass in air rapidly to a temperature above the transformation temperature heated the glass and then quenched. The are for the tempering process temperatures required in the range of 580 ° C thereby to 680 ° C, preferably in the Range from 600 ° C to 650 ° C. The same temperature range is also needed when the forth of the glassmaking plan glass sheets are subjected to a bending process, to, in certain applications, eg. B. on the car mobile sector, to obtain curved glass panes.

With the generic method previously carried on the bring the metal layer as well as of course the on bringing the metal oxide after completion of bias and bending process and cooling of the discs, which end in usually vacuum-coating process for application come.

This method, the coating subsequent to perform the toughening or bending process, has ver distinct disadvantages compared to a procedure where the first applied coating and then the toughening or bending process would be carried out. So may be coated in the former case only fixed dimensions, as biased discs known not cut can be. For the coating technique, it is because against much cheaper, unit dimensions, in particular the Tape measures of glass forming the float process to be layers. In the latter case can be with vacuum Coatings, the problems of a uniform layer much lighter and easier to solve thick, as if hard dimensions with respective gaps between the individual Discs are coated in the coating field. in addition is that the transport of such unit extent by the Coating systems, is less complicated than if transported individual pieces of various dimensions Need to become.

A further disadvantage is that by the high temperatures of the toughening or bending process Impurities on the glass surface often with received her such a strong bond that they in subsequent surface cleaning before implementation the coating process is no longer so far ent can be removed, such as for the subsequent Coating process is necessary. They are quasi baked into the glass surface. That leads to a disturbing deterioration of the coating quality.

In the case of the coating of curved panes are naturally the problems, a sufficient layer DC get temperance, particularly large, because angle and distance to the coating sources by additional change of curvature of the discs. Come in addition, that the expenditure for vacuum coating equipment for Coating curved discs substantially greater than the planner for coating disks, since A gangs- and output locks and locks between various coating stations considerably wider are formed as the coating of flat glass have to.

For these reasons, has a procedure in which flat glass, particularly in the form of unit dimensions, coated, and then - in particular after production of the fixed dimensions by cutting - pre clamped or bent, considerable advantages. These However, procedure is in the generic Method, ie when the metal layers, which for said applications are used, not feasible because the required Tem temperatures above 480 ° C disturbing layer modifier Derun gene - in particular by the oxidation of the layers - be caused.

This results, for. Example, from DE-OS 17 71 223. You be writes to a process for the production of oxide layers, after which by vacuum evaporation produced metal layers or sub-oxidic layers of these metals, the special layers from the group of the metals cobalt, Iron, manganese, cadmium, bismuth, copper, gold, lead, and Nickel a heat treatment step at temperatures subjected to between 315 ° C and 677.5 ° C and thus in the corresponding oxides are converted. By However, conversion into the oxides increases the transmission the layers, especially in the near infrared. In order to deteriorates undesirably Suns protective action against the metal layers.

In addition, combinations of these metal layers were proposed layers with transparent oxide layers. So can on the glass substrate side facing away from the Metal layer a transparent oxide layer as a protective layer to improve the mechanical properties or when formed as a quarter-wave layer of the visible area as antireflection coating to increase be arranged selective transmission. In another Formation of such coating systems, it is provided that Metal layer on both sides in high-index antireflection embed layers of metal oxides (see, eg. B. JP-OS 58 719 54-0). In addition, it has also been proposed to increase the long-term stability such layer systems between the metal layer and the anti-reflection layer, which on the glass base remote side of the metal layer is arranged, arranging another thin metal layer (EP-OS 00 35 906).

Investigations carried out have shown that at Layer arrangements such as those described above, in which a metal layer by an oxide layer on the is the glass substrate side remote protected, not from reaching stability can be achieved, if this exposed layer arrangements of temperature stress are, as occurs when biasing or bending process.

Such a layer arrangement, as well as the genus modern method is obtained, for example from the US-PS 38 46 152 generally known.

EP-OS 01 08 616 teaches the production of curved Vehicle window panes with electrically conductive Metalloxidbe coating the bending process in order to avoid cracking for a given sub-stoichiometric condition carry the metal oxide layer. The DE-PS 9 17 347 deals with a method for preparing electrically- conductive layers, wherein a sub-stoichiometric Tin oxide or indium oxide layer on a glass substrate applied and then by heating in air a Conversion is performed in the complete oxide. relate to US Patent No. 39 62 488 and US-PS 40 17 616 also the production of electrically conductive Be coatings with high light transmittance, in which However, a silver or gold layer on both sides in Titan oxide layers is embedded and the titanium oxide to avoid agglomeration of the noble metal layer be applied with an oxygen deficit. closing Lich, DE-OS 30 27 256 discloses the use of under stoichiometric titanium oxide as a component of cladding for transmission changing Metallschich th with the purpose, in this way, among other measures the corrosion resistance, etc. of the metal layers to improve. However, leave the latter in the Publications listed combinations of materials, in particular cially in a procedure according to DE-OS 30 27 256 not in a method of the generic type in a running such a manner that, in a modification of the previously known process control coating of the glass substrate took place before the opening process: Such Ver drive as leads namely thereby inevitably lead to an disturbing change in the metal layer, either by Oxidation, or by agglomeration, so that this Documents can not give any suggestion to the to avoid the disadvantages of the generic process.

The invention is therefore based on the object, the generic method to further develop, that only the coating of the glass substrate connected after toughening or bending process ver avoid driving even disadvantages and without the risk of layer changes the metal layer the neces sary coating measures before the Prior Clamping and / or bending process can be performed.

This object is achieved in that both the metal layer and the protective layer before the thermal toughening and / or bending process on the substantially planar glass substrate are applied; and that the protective layer having an oxygen deficit <i>x</i>, based on a metal atom of the metal oxide or metal oxides, from 0.05 <i>x</i> 0.4 and in a thickness of 10 nm to 100 nm is applied in such a composition that the toughening and / or bending process no appreciable Oxygen diffusion takes place up to the metal layer.

A preferred embodiment of the invention is characterized is characterized in that as a protective layer a layer of or with a preponderant content of at least one Metal oxide or metal oxide from the group Sn, In, Ta is applied.

It can be provided that the oxygen deficit in the range 0.1 <i>x</i> 0.3.

The invention further also provides that the protection layer an indium oxide layer having the composition InO_1,5-<i>x</i> is applied.

Alternatively, the invention provides, if necessary, in that, as Protective layer, a tin oxide with the composition SnO_2-<i>x</i> is applied.

Also can be inventively provided that the protection layer a tantalum oxide having a composition of TaO_2,5-<i>x</i> is applied.

A further embodiment of the invention proposes, that the thickness of the protective layer is at least 13 nm.

It can be so proceeded that the thickness of the protective layer about 20 nm to 70 nm.

In a further embodiment it can be provided that on the protective layer a top layer of at least one Metal substantially stoichiometric composition is applied.

The invention is in a particular embodiment, further characterized in that the covering layer min least one metal of that group has, from the metal oxide or metal oxides for the Protective layer is or are selected.

It can be easily understood that the metallic Composition of the outer layer to that of the protection layer corresponds.

Finally, the invention provides, if necessary, also happens that on the glass support prior to applying the metal layer (s) at least one sub-layer of a metal, Metal alloy, a metal oxide or mixed metal oxide is applied.

The invention in the course, for example, when prestressed parapet plates or the like to be, the light transmittance of the glass sheet on Zero can be reduced, based on the surprising Recognizing that required for tempering or bending Protective effect of a on the glass substrate side facing away then reaches the metal layer deposited oxide , when the oxide layer of the in composition from stoichiometric composition of the relevant oxide differs. What is needed is an oxygen deficiency, which has a Maximum and minimum value does not exceed or fall below allowed. Also, it is necessary that, when a metal layer perform a predominant amount of a metal or Me tallegierung of the elements with atomic numbers having 22-28 of the Periodic Table, the protective layer of suitable, according to the invention's proposed material consists; a combination of materials, such as z. B. from the DE-OS 30 27 256 is known, would be totally useless because upon heating of the discs described therein to bending or bias temperature, the metal layer inevitable gets destroyed.

This result is unexpected. One would assume namely, that the action of oxygen on the metal layer upon heating then is the lowest when the Protective layer is present, the stoichiometric composition. The diffusion through a layer is namely known over imperfections in the layer. Their number is, however, on lowest when the stoichiometric composition of Oxide is present. The reasons for the observed protective effect in the range of a certain oxygen deficit are not known.

It is also surprising that the oxygen deficit Protective layer and a predetermined value does not may proceed. Thus, layers with higher Sauer material deficit unsuitable. When using such Layers it comes back to a stronger change the optical data of the protected metal layer, in particular occur after the temperature treatment Spotting and clouding phenomena. It's closed suggests that particularly strong in this unterstöchiomet aides, oxidizes the protective layer unevenly is so as to the formation of additional grain boundaries with increased oxygen diffusion or cracking in the Coating comes. However, again because of Komplexi ity of processes only guesses possible.

As materials for the metal layer are the elements with atomic numbers 22-28 of the Periodic Sy stems, in particular the metals chromium, iron, nickel, titanium and vanadium, and alloys of these metals, but also Compositions having a predominant content of one of the aforementioned metals or metal alloys.

Have proved z. B. chromium-iron-aluminum alloys.

As protective layers, layers have made or with egg nem predominant amount of at least one metal oxide or metal oxide from the group Sn, In, Ta as suitable proved. As already stated, this oxide must or Mixed oxide in deviation from stoichiometric Composition of oxides a certain oxygen deficit exhibit. This deficiency is, in each case based on a Metal atom of the corresponding oxides, approximately equal. The required composition meets the relationship InO_1,5-<i>x</i>, SnO_2-<i>x</i>, TaO_2,5-<i>x</i>, in which <i>x</i> in the range 0.05 <i>x</i> 0.4.

It has been found that the thickness of the oxide layer with not fall below a minimum value of oxygen deficit allows for in connection with the temperature cycle of the Toughening or bending process sufficient protection is effectively available. This minimum thickness is about 10 nm, preferably 13 nm.

Thicker layers can also be used. The is, for. example, the case when via their Interferenzwir kung on the metal layer additional optical effects, such. as an antireflection effect or a color effect, are to be achieved. The oxide layers required for this lie generally in the range of about 20 nm to 70 nm.

In the existing oxygen deficit of the protective layers , these generally have a hardness and abrasion resistance to as the for further manipulation coated glass carrier before the tempering or bending is required. However, these values ​​are slightly below those who stoichiometric with oxide layers to composition are achieved.

To further improve the coating hardness and Abriebfestig speed, a method has been proven, in which first the Protective layer having oxygen deficit in the required set minimum thickness and about a further oxide layer is introduced. The second oxide layer may be an oxide layer stoichiometric composition of the same metal, as it is used in the protective layer be. It can however, an oxide layer of another metal on to be brought. This method of applying a Double layer is particularly advantageous if it is due to wünschter optical effects, the layer thickness required is above the minimum value for the protective effect, since then this aspect with an even improved Coating hardness can be combined. Within the He making idea, it is otherwise quite naturally possible between the glass substrate and the metal layer further layers, for example, silver or Palladium layers or the like to arrange, according to the desired spectral or generally optical properties companies, as long as in the invention substantially Way remote the metal layer on the glass carrier Side by a substoichiometric applied Protective layer of the composition and thickness according to the invention against the Herandiffundieren of oxygen in the Bending and / or toughening processes required times and temperatures will be protected.

The coating according to the invention it is usually followed by vacuum coating. The Layers can by evaporation from resistance heated evaporator devices or else by Electron beam evaporation are applied. Further suitable sputtering as DC or Niederfrequenzzerstäubung, but especially high frequency and MAGNETRON sputtering. The metal or Metal alloy layers can either by di rektes evaporation or sputtering in neutral Atmos phere are produced. For the production of oxide layers the process is suitable reactive Ver evaporation, especially the method of reactive Atomization. Particularly economical this is the Ver drive the reactive Magnetron sputtering, in which appropriate metal or metal alloy targets in an Atmosphere containing oxygen and Others atomized, will. This method can be the necessary Setting the oxygen deficit of layer well defined.

Further features and advantages of the invention result from the following description, in the embodiment examples reference to the schematic drawing, in are explained. In which:

<b>Fig.</b> 1 shows a first embodiment of an after The method according to the invention can be prepared glass slice in a section perpendicular to the disk plane;

<b>Fig.</b> 2 shows a further embodiment of an after produced the inventive method Glass, perpendicular also in section to the disc plane;

<b>Fig.</b> 3 shows the spectral transmittance before and after Carrying out the tempering process for according to Example I produced glass sheet;

<b>Fig.</b> 4, the spectral transmittance before and after Carrying out the tempering process for Example II;

<b>Fig.</b> 5, the spectral transmission according to Example III Glass produced before and after the Tempering process; and

<b>Fig.</b> 6 the results of appropriate Spektralmes ments of methods according to Example IV.

In the in <b>Fig.</b> 1 illustrated embodiment is on a glass slide <b>10</b> a metal layer <b>12</b> of nickel with a thickness of 10 nm is applied, to which a protective layer <b>14</b> connects with a thickness of 20 nm, the front the tempering process, the composition SnO_1.7 Has.

In the embodiment of <b>Fig.</b> 2 transmits the glass substrate <b>10</b> successively an underlayer <b>16</b> from In₂O₃ with a Thickness of 6 nm, which acts as an adhesion-promoting layer, a metal layer <b>12</b> of cobalt with a thickness of 22 nm, a protective layer <b>14</b>That before the tempering process the composition SnO_1.7 has, with a thickness of 16 nm and a covering layer <b>18</b> of SnO₂ thick of 20 nm.

Slices of in <b>Fig.</b> 1 and 2 are reproduced in Art By working analogously to the hereinafter be written examples produced:

example I

In a vacuum coating plant, which with Beschich relief devices for Magnetron sputtering from the armed men were on a float glass pane in the format 10 cm × 10 cm in succession the following layers are applied: First, a nickel layer to a thickness of 8.5 nm by Sputtering of a nickel target in an argon atmosphere at a pressure of 5 · 10^-3 mbar. Subsequently, the Nickel layer, a tin oxide by reactive Zer pollination of a Zinntargets in an argon-oxygen Atmos phere with 40% oxygen at a pressure of 4 x 10^-3 mbar applied. The coating parameters of the reactive sputtering were chosen so that the Layer, the composition SnO_1.83 exhibited. Together tion was there to prepare the overall coating determined by Auger electron analysis. The thickness of the Layer was 28 nm.

The coated disc had in the review and in Be trachtung from the glass side a neutral appearance. The coated wheel was then in a preload Oven heated to 600 ° C and quenched. By ago span process changed the appearance of the disc practically not.

In <b>Fig.</b> 3 is a curve 1 and curve 2 the spectral Trans mission before and after carrying out the tempering process for the wavelength area of ​​300 to 800 nm reproduced. As out <b>Fig.</b> 3 can be seen, the change in the transmission, in particular in the visible spectral range, slightly. These minimal changes are probably due to the further oxidation of the outer protective layer in front of span process and the associated decrease in the Oxygen deficit existing residual absorption caused. Added to this are Tempereffekte by this temperature treatment, as they generally occur in vacuum layers.

example II

The procedure was as in Example I, with the difference that the tin oxide layer by appropriate choice of Be coating parameters without measurable oxygen deficit, ie corresponding to the stoichiometric composition of the SnO₂was applied.

The results of the spectral measurements prior to and after passing implementing the tempering process at 600 ° C are as curve 1 and 2 in <b>Fig.</b> 4 reproduced. They show that by the tempering process significantly increases the transmission, ie a noteworthy light attenuation and sunscreen effectively no longer exist.

example III

The procedure was as in Example I, with the difference that the coating parameters in the preparation of Tin oxide were adjusted so that a sub oxide layer of the composition SnO revealed.

The spectral transmittance of the coated pane before the tempering process is as curve 1 in <b>Fig.</b> 5 reproduced. Due to the high absorption capacity of the SnO layer results in substantially lower transmittance values ​​than in Example I and II. After completion of the Vorspannpro zesses (curve 2) delivers a significant Transmissionser increase on. In addition, a coating mottled appearance, and is therefore for the above Applications not suitable.

example IV

In the coating system according to Example I were tested for a float glass plate of 10 cm × 10 cm in succession The following layers are applied:

<ul><li>- A SnO₂Layer of 20 nm thickness by reactive Zer atomization of a tin target at a pressure of 4 x 10^-3 mbar in an argon-oxygen atmosphere, the Composition 50% O₂, 50% Ar;</li><li>- A nickel layer of thickness 2 nm by sputtering from a nickel target in an argon atmosphere at a Pressure of 4 x 10^-3 mbar;</li><li>- A silver layer of 8 nm thickness by sputtering of a silver target in an argon atmosphere at a pressure of 3 x 10^-3 mbar;</li><li>- A nickel layer of 3 nm thickness by sputtering of a nickel target in an argon atmosphere at a pressure of 4 x 10^-3 mbar;</li><li>- A tin oxide of the composition SnO_1.70 with a Thickness of 30 nm by reactive sputtering from a Tin target at a pressure of 4 x 10^-3 mbar in a Argon-oxygen atmosphere of the composition 35% O₂. 65% Ar.</li></ul>

The coated pane exhibited in transmission a easy umbral on color cast when viewed from the glass side was the disc practically neutral. The carried out spectral measurements (curve 1, <b>Fig.</b> 6) show that the disc in the visible area a high Light transmission combined with a low trans mission in the near infrared has, ie the Suns protective effect is very good.

After carrying out the tempering process resulted in the reproduced as curve 2 transmission curve. She shows, that the optical data for the total radiation field the sun are essentially retained. Only in the shortwave visible spectral region is the Trans mission somewhat higher than previously. This increase in transmission, presumably by the post-oxidation of SnO_1.70-Layer is caused, reduce the originally present slight color cast, thereby improving the transparency.

The in the above description, in the drawing and the claims disclosed features of the invention may, both separately and in any combination for realizing the invention in its various NEN embodiments be essential.

<ul><li>LIST OF REFERENCE NUMBERS<b>10</b> glass slides<b>12</b> metal layer<b>14</b> protective layer<b>16</b> interlayer<b>18</b> topcoat</li></ul>