DE102014114330B4 - Solar control layer system with neutral coating color on the side and glass unit - Google Patents

Abstract

Solar control layer system on a transparent dielectric substrate (S) with at least the following layers viewed from the substrate (S): - a silicon-containing dielectric base layer (GS), - a first functional layer (FS1), - a dielectric intermediate layer (ZS), A second functional layer (FS2), a silicon-containing dielectric cover layer (DS), the refractive index of the intermediate layer (ZS), referred to below as low-refractive dielectric interlayer (ZS), at a wavelength of 550 nm smaller than the refractive index of the base layer (Z) GS) and the cover layer (DS).

Description

The invention generally relates to a solar control layer system on a transparent, dielectric substrate and a glass unit.

Such solar control layer systems, hereinafter also referred to only as layer systems are, z. B. applied to glass by means of vacuum coating, mainly used in architecture for window and facade design and in the automotive industry. The goal is a reduction of the total energy transmittance g. The total energy is composed of the part of the solar radiation energy, which passes directly through the glass by means of transmission of visible light and radiation in the wavelength range of the near infrared (about 780 nm to 3 microns) in the interior of the room and the energy, the previous Glass heating is delivered to the inside, wherein at most the proportion can be delivered, which was previously absorbed. The smaller the g-value, the higher the sunscreen effect.

The layer system by its structure nonselectively reduces the transmission over the entire wavelength range of visible light from about 380 nm to 780 nm equally, depending on the specific application, a certain transmittance is desired.

In addition, a predetermined level of reflection and / or absorption capacity for radiation in the spectral infrared range, in particular for wavelengths λ> 3 μm, may be required in order to reduce heat input from the outside.

The usual solar control layer system usually comprises three layers. Occasionally, two or more functional layers are used ( WO 2012/096771 A1 . US 2011/0146172 A1 . DE 2524461 A1 ), wherein the functional layer is regularly embedded between two dielectric layers, a base layer and a cover layer, for example of silicon nitride Si ₃ N ₄ , the z. B. the anti-reflection, preventing diffusion processes, the adhesion improvement and / or increasing the mechanical stability of the layer system serve. The functional layer used here is a layer which has a relatively high absorption and low reflection in the solar range (visible light and near infrared to λ <2 μm). This reflection and / or absorption of the infrared radiation is realized within the layer system mainly by a metallic or metal nitride functional layer, hereinafter referred to only as a functional layer, for example of CrN, NiCr, Cr, Ni, NiNx, CrNx or NiCrNx.

Another property of the coating systems described is their suitability for a heat treatment (tempering), z. B. in the manufacture of safety glass in the architectural and automotive sector and the shaping, z. B. in the manufacture of windshields. Since the coating of the substrates for process engineering and cost reasons usually takes place before the heat treatment, layer systems are mainly used, the mechanical and optical properties of which do not worsen or not significantly by the heat treatment.

In this embodiment, in order to avoid predominantly temperature-induced diffusion and oxidation processes impairing the functional layer, a blocking layer can be deposited on one or both sides of the functional layer, which serves as a buffer for the diffusing components. These blocking layers are arranged according to the temperature load that occurs and protect the sensitive, often very thin functional layer against the influence of adjacent layers.

In the field of architectural glazing, a solar control layer system is generally applied to position 2, that is to say on the inside of the first, outer pane of a double-pane insulating glass unit. In special cases, however, an application to position 1, that is, on the outside of the first outer pane of a Zweiperibenisolierglaseinheit possible.

In particular for architectural glazings, the color impression of the coated substrates plays an important role. Neutral colors in the CIE L * a * b * color system are characterized by a * and b * color values of approximately zero, while green colors are characterized by negative a * color values, blue colors by negative b * color values, red colors by positive a * color values and yellow colors are characterized by positive b * color values.

As an alternative to the CIE L * a * b * color system, color values can also be specified in the XYZ system, where the Y coordinate is used as the brightness value (luminance). The larger the Y value associated with a color, the more intense the color appears.

Occasionally, for example, for the cladding of building facades a very specific, sometimes intense, substrate-side reflection color, characterized by certain a * (Rg) - and b * (Rg) values desired to a certain color association, that is, a certain emotional and to cause psychological effect or to bring about a harmonious adaptation to the environment. For example, from the document DE 10 2013 112 990 A1 a solar control layer system with an intense color impression known.

Especially in layer systems with specifically colored Rg values, eg. B. with a blue, green or golden substrate-side color impression, d. H. in the case of architectural glazing viewed from the outside, unfavorable, z. B. yellow-brown or reddish, layer-side color values (reflection color values a * (Rf) and b * (Rf) and transmission color values a * (T) and b * (T)). This is visually extremely unpleasant and therefore highly undesirable.

The object of the present invention is to specify a solar control layer system deposited on a substrate, which has as neutral as possible layer-side reflection color values as well as transmission color values. Furthermore, the transmittance and the substrate-side color values of such a layer system should be adjustable.

In particular, it is desired to provide such a layer system whose Y (Rg) value is as high as possible so that the substrate-side color impression is as intense as possible. The layer system should also have a high chemical and mechanical stability, including in terms of color, as well as be produced temperable and inexpensive.

Furthermore, the emissivity of the layer system, i. That is, the measure of the ability of a surface to return absorbed heat as radiation is to be as low as possible.

To achieve the object, a solar control layer system with the features of claim 1 and a glass unit with the features of claim 12 are given. Advantageous embodiments are the subject of the dependent claims.

The solar control layer system according to the invention is arranged on a transparent dielectric substrate, in particular made of glass or a polymer material.

The layer system comprises a silicon-containing dielectric base layer. In particular, it serves to reduce unwanted diffusion processes from the substrate into the overlying layer system and in particular into the functional layers, thereby contributing to the stability of the entire layer system. In addition, the base layer ensures good adhesion of the subsequent layers. The base coat can also serve for the anti-reflective coating and influences the color setting.

A good barrier effect, which is particularly important for layer systems to be tempered due to the increased tendency to diffusion at higher temperatures, is achieved in particular by those layers which, in addition to the specific ion scavengers, also have a dense structure, especially for sodium ions.

Due to its dense structure and the associated good barrier properties against diffusion of sodium ions and its temperature stability of the growth structure, Si ₃ N ₄ in particular is suitable for heatable layer systems.

The layer thickness of the base layer is preferably in the range between 9 and 115 nm.

Arranged above the base layer is a first functional layer which absorbs and / or reflects the incident solar radiation at least partially, in particular in the IR range. The layer thickness of the first functional layer is preferably in the range between 1 and 15 nm.

Over the first functional layer, a low-refractive dielectric interlayer is arranged. Low refractive index means that the refractive index of the intermediate layer at a wavelength of 550 nm is smaller than the refractive index of the base and top layers. The layer thickness of the intermediate layer is preferably in the range between 30 and 100 nm.

Arranged above the intermediate layer is a second functional layer which likewise absorbs and / or reflects the incident solar radiation at least partially, in particular in the IR range. The layer thickness of the second functional layer is preferably in the range between 15 and 40 nm.

Optionally, one or more further functional layers may be arranged above the second functional layer, the individual functional layers being separated from one another by low-dielectric intermediate layers.

At the top, the layer system is completed by means of a silicon-containing dielectric cover layer, which may consist, for example, of Si ₃ N ₄ or silicon oxynitride. The cover layer serves, in particular, for the mechanical and chemical protection of the layer system and the antireflection coating. With Si ₃ N ₄ as the material of the cover layer, due to its dense structure, particularly stable layer systems can be produced. The layer thickness of the cover layer is preferably in the range between 25 and 100 nm.

The layer system according to the invention can optionally further layers such. B. contain adhesion, germ and / or blocking layers, which support the function of the described layers.

For example, it can be deposited on the substrate by means of physical vapor deposition. Preferably, the deposition takes place by means of magnetron sputtering, which enables the production of dense individual layers even with small layer thicknesses.

The layer properties can be very good and reproducible by means of the type of sputtering process, such. DC (DC), MF (mid frequency), pulsed DC (pulsed DC) or DAS (dual anode sputtering) sputtering, and sputtering parameters. In addition, both tubular targets and planar targets can be used.

"Consisting of" includes, based on all layers of the layer system, that technologically related impurities or technologically related admixtures, the process control during deposition or, z. B. in the sputtering, are useful for target production, may be included. Such impurities or technological admixtures are usually in the range of less than 1 At .-%, but can also be a few percent. The stoichiometric compounds mentioned include minor stoichiometric deviations, provided that they are not associated with significant changes in properties. In addition, so-called gradient layers can also be used, ie layers whose composition changes over the layer thickness. Alternatively, in particular, the functional layer can be constructed from several partial layers of different materials.

The layer system of the invention is characterized by a largely neutral layer-side reflection color and transmission color, d. H. a * (Rf), b * (Rf), a * (T) and b * (T) are close to zero. Preferably, the color value a * (Rf) is in the range between -4 ≦ and ≦ 4. The color value b * (Rf) is preferably in the range between -7 ≦ and ≦ 0. In addition, the color value a

Adjust the transmittance and the substrate-side reflection color, the substrate-side reflection color is primarily adjusted over the thickness of the base layer, while the materials of the individual layers play only a minor role for the achievable color impression.

Furthermore, the layer system according to the invention has a high Y (Rg) value, which makes the substrate-side reflection color appear particularly intense.

The layer system according to the invention is also chemically and mechanically resistant according to the current standards and can be due to the simple structure effectively in terms of time and material requirements and thus produce cost. Cost-effectiveness is further enhanced by the ability to produce the desired color layer system with materials known and tested for their processing and variability used in regular plant configurations. This can be waived even with a desired reflection color, often on conversions, which increases the utilization of a plant.

When using Si ₃ N ₄ as the material of the base layer, the layer system according to the invention is also temperable, which includes the same or at least an optically imperceptible change in the reflection color of a tempered compared to the untempered layer system.

The functional layers of the layer system can optionally consist of the same material or of different materials.

Particularly suitable as material for the functional layers are metals, metal alloys, semiconductors or compounds of metals, metal alloys or semiconductors, in particular stoichiometric or substoichiometric nitrides. The functional layers can preferably consist, for example, of chromium, nickel-chromium NiCr, titanium or their stoichiometric or substoichiometric nitrides.

Particularly suitable is stoichiometric titanium nitride TiN, since with such a layer system a higher electrical conductivity than in the prior art can be achieved. This is accompanied by a desired reduction in the emissivity of the layer system. For example, depending on the specific design of the layer system after annealing, emissivities of less than 0.6 and, if blocker layers are used, even less than 0.5 can be achieved. Conventional solar control layer systems, however, have a much lower conductivity and therefore show the same emissivity as the uncoated substrate, in the case of glass about 0.87.

According to one embodiment variant, the low-refractive dielectric interlayer consists of Al ₂ O ₃ , an aluminum oxynitride, SiO ₂ or a silicon oxynitride with a refractive index of less than 2.0 at a wavelength of 550 nm. The intermediate layer is preferably made of silicon oxynitride having a refractive index between 1.75 and 1.95 at a wavelength of 550 nm. In the event that the layer system comprises a plurality of intermediate layers, also several or all intermediate layers may consist of one of said materials.

Optionally, the layer system may comprise one or more blocking layers, which are arranged adjacent to, in particular in direct contact with, at least one functional layer. Such blocker layers prevent a color change due to an annealing process. The blocking layers may be made of, for example, NiCr or a nickel-chromium nitride. The layer thickness of such a blocking layer is preferably in the range between 1 and 5 nm.

According to a preferred embodiment, a blocking layer of NiCr or a nickel-chromium nitride is arranged only directly above the last functional layer, since the layer system must be protected during an annealing process, in particular from oxidation processes with the surrounding atmosphere.

A glass unit according to the invention has at least two glass substrates, which are connected with or without a distance from each other via suitable means for connection. The glass unit can for example act as an insulating glass unit or as a laminated glass unit, z. B. as vehicle or safety glazings, in which two glass substrates as discs without space via a connecting means, for. As a film directly connected to each other.

One of the glass substrates has a layer system according to the invention, wherein the coated glass substrate within the glass unit is usually arranged such that the coating lies between the substrates, preferably at position 2 of the glass unit.

The invention will be explained in more detail with reference to two embodiments. The accompanying drawings show in

1 schematic structure of a solar control layer system according to the prior art,

2 schematic structure of a solar control layer system according to the first embodiment,

3 schematic structure of a solar control layer system according to the second embodiment,

4 Comparison of the achievable color values, resistances and emissivities of the untempered single pane.

A solar control layer system according to the prior art ( 1 ) has, viewed from the substrate S (6 mm thick glass), the following layers: a base layer GS of Si ₃ N ₄ with a layer thickness in the range between 18 and 228 nm, a functional layer FS of a chromium nitride CrN _x with a layer thickness between 9 and 17 nm and above a cover layer DS also of Si ₃ N ₄ with a layer thickness in the range between 18 and 54 nm. For such a layer system, the result in 4 given color values and a resistance greater than 1000 Ω, so that the layer system according to the prior art is classified as non-conductive.

According to a first exemplary embodiment of the layer system according to the invention ( 2 ) is on a 6 mm thick glass substrate S, a base layer GS of Si ₃ N _{4 arranged} with a layer thickness in the range between 9 and 115 nm. Directly thereafter follows a first functional layer FS1 of a nickel-chromium nitride NiCrN _x or a chromium nitride CrN _x with a layer thickness between 2 and 10 nm. Directly above the first functional layer FS1 is a low-refractive dielectric interlayer ZS of a silicon oxynitride SiO _x N _y with a layer thickness in the range between 30 and 100 nm arranged. The refractive index of the intermediate layer ZS at a wavelength of 550 nm is between 1.75 and 1.95.

Directly above the intermediate layer ZS is the second functional layer FS2 made of a titanium nitride TiN _x with a layer thickness between 15 and 40 nm. Directly above the second functional layer FS2 is a cover layer DS of Si ₃ N ₄ with a layer thickness in the range between 30 and 100 nm arranged.

With the layer structure mentioned can be in 4 reach specified color values. In comparison with the prior art, the layer system according to the invention has a neutral layer-side reflection color and transmission color, ie a * (Rf), b * (Rf), a * (T) and b * (T) are close to zero. In addition, the layer system according to embodiment 1 has a significantly reduced resistance, which is reflected in a reduced emissivity.

The second embodiment ( 3 ) differs from the first embodiment in that between the second functional layer FS and the cover layer DS a blocking layer BS of NiCr or a nickel-chromium nitride NiCrN _{x is} arranged. The layer thickness of the blocking layer BS is in the range between 1 and 5 nm, the other layer thicknesses are formed according to the embodiment 1.

Also, the color values associated with the second embodiment can 4 be removed. Compared to the embodiment 1, the resistance and thus the emissivity are reduced again.

LIST OF REFERENCE NUMBERS

• S

  substratum

  S1

  second substrate

  GS

  base layer

  FS, FS1, FS2, FSx

  functional layers

  ZS

  interlayer

  BS

  blocker layer

  DS

  topcoat

Claims (12)

 Solar control layer system on a transparent dielectric substrate (S) with at least the following layers viewed from the substrate (S) upwards: A silicon-containing dielectric base layer (GS), A first functional layer (FS1), A dielectric intermediate layer (ZS), A second functional layer (FS2), A silicon-containing dielectric covering layer (DS), - wherein the refractive index of the intermediate layer (ZS), hereinafter referred to as low-refractive dielectric interlayer (ZS), at a wavelength of 550 nm is smaller than the refractive index of the base layer (GS) and the cover layer (DS). Layer system according to claim 1, wherein the low-refractive dielectric interlayer (ZS) of Al ₂ O ₃ , an aluminum oxynitride, SiO ₂ or a silicon oxynitride having a refractive index less than 2.0, in particular a refractive index between 1.75 and 1.95, at one wavelength of 550 nm. Layer system according to claim 1, wherein over the second functional layer (FS2) one or more further functional layers (FSx with x = 3, 4, ...) are arranged, which are separated from the respectively underlying functional layer (FSx - 1) by a further low-refractive dielectric layer Intermediate layer (ZS) are separated. Layer system according to claim 1, 2 or 3, wherein the functional layers (FS) consist of the same material or of different materials. Layer system according to one of the preceding claims, wherein the functional layers (FS) consist of a metal, a metal alloy, a semiconductor or a metal or semiconductor compound, in particular a stoichiometric or substoichiometric nitride. Layer system according to claim 5, wherein the functional layers (FS) consist of chromium, NiCr, titanium or their stoichiometric or substoichiometric nitrides, in particular TiN. Layer system according to one of claims 3 to 6, wherein at least one of the low-refractive dielectric intermediate layers (ZS) of Al ₂ O ₃ , an aluminum oxynitride, SiO ₂ or a silicon oxynitride having a refractive index less than 2.0, in particular a refractive index between 1.75 and 1 , 95, at a wavelength of 550 nm. Layer system according to one of the preceding claims, wherein the base and cover layer (GS, DS) consists of Si ₃ N ₄ . Layer system according to one of the preceding claims, wherein one or more blocking layers (BS) are arranged adjacent to at least one functional layer (FS). Layer system according to claim 9, wherein only directly above the last functional layer (FS) a blocking layer (BS) of NiCr or nickel chromium nitride is arranged. Layer system according to one of the preceding claims, wherein the color value a * (Rf) of the layer system in the range -4 ≤ a * (Rf) ≤ 4 and the color value a * (T) of the layer system in the range -4 ≤ a * (T) ≤ 4 and / or the color value b * (Rf) of the layer system in the range -7 ≦ b * (Rf) ≦ 0 and the color value b * (T) of the layer system in the range -6 ≦ b * (T) ≦ 2. Glass unit comprising at least two glass substrates (S, S1) which are interconnected with or without a distance from one another via means for connecting the glass substrates (S, S1), one of the glass substrates (S, S1) comprising a layer system according to one of the preceding claims.

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