RU2811705C2 - Coated window glass - Google Patents

Abstract

FIELD: window glass.

SUBSTANCE: present invention relates to a transparent substrate comprising a multilayer coating stack and its use in the manufacture of a double glazing unit, the multilayer coating stack comprising n functional metal layers m, where n is from 4 to 6, and (n+1) dielectric layers, d. Dielectric layers are located before and after each functional metal layer. Each dielectric layer contains one or more layers, characterized in that the geometric layer thickness for each functional metal layer in the coating package Gm is greater than the geometric layer thickness for each functional metal layer located before it in the multilayer coating package. For each dielectric layer d located before and after each functional metal layer m, the optical thickness of the layer (opl_n ) is greater than or equal to the optical thickness of the layer (opl_n-1) located before it in the coating stack, provided that twice the optical thickness of the layer of the first dielectric layer (opl₁) in the coating package is less than the optical thickness of the layer of the second dielectric layer (opl₂) in the coating package, the doubled optical thickness of the layer of the last dielectric layer (opl_n+1) in the coating package is greater than the optical thickness of the penultimate layer dielectric layer (opl_n).

EFFECT: optimization of the sun protection properties of window glass with high selectivity with minimal colour change.

15 cl, 4 ex, 5 tbl, 5 dwg

Description

The present invention relates to a coated substrate, and more specifically, the present invention relates to a transparent coated substrate, said coating comprising multiple layers, some of which contain functional layers that reflect solar radiation and/or infrared radiation.

Transparent substrates containing, for example, glass can be provided with coatings to reduce the emissivity ("low-emissivity coating") of the substrate and to achieve thermal insulating properties when the substrate is installed, for example, in a building, by reflecting infrared radiation emitted, for example, from inside the building , and/or to reduce its permeability to solar energy (“solar protection coatings”), to shield interior spaces from excess solar energy (heat).

Coatings that provide such low emissivity (low emissivity) and/or solar control when applied to glass substrates can be deposited, for example, by physical vapor deposition methods such as sputtering. Sprayed low-e and solar control coating packages typically consist of repeating sequences such as:

"substrate/ base dielectric layer sequence _a / silver (Ag)/ dielectric layer sequence _b ", wherein each of the dielectric sequences a and b does not necessarily have the same thickness or composition.

In layered systems of this type, the silver layer serves primarily as an infrared (IR) reflective layer, while dielectric layers ("D _L ") can be used, through suitable selection of material and thickness, to influence transmittance and reflections in the visible region of the spectrum, as well as the energy emitted as thermal energy, i.e., the emissivity and transmittance of solar energy for the coated glass substrate.

Reflections adversely affect visibility through glass substrates. This problem is especially significant for applications where good visibility through the glass substrate is critical to their functionality.

In addition, there is a continued demand in the glass industry for coated glass substrates that meet the stringent automotive and architectural oxidation performance requirements in terms of thermal insulation properties and desired low emissivity, resulting in the use of a range of dielectric materials to coat glass substrates. more complex sequences of layers (or packages). Consequently, in the glass industry, a number of dielectric sequences in a coated substrate of two or even three is becoming increasingly common.

For example, WO 2011/020974 describes a transparent glass substrate provided with a thin film multilayer structure comprising an alternating array of at least three metal functional layers and four anti-reflection coatings disposed on each side of the metal functional layers, the anti-reflection coatings also comprising multiple layers .

US Pat. No. 5,595,825 discloses a substrate coated with a film stack containing at least three films having reflective properties in the infrared (IR) region of the spectrum and which has high selectivity, i.e., a high ratio of light transmittance T _L to solar factor (SF), (TL/SF), for a given value of T _L .

US 2013/0057951 describes a layer system with n functional layers, for example based on silver and n+1 dielectric layers. The absorbent layer located in the bag is important.

US 2017/0059753 also describes a film with multiple metal functional layers (eg silver) with at least one absorbent layer. The functional layers are surrounded by phase control layers (dielectric layers).

CN 102372447 discloses low emissivity glass containing four layers of silver coating for automotive and architectural glass, as does US 2011/0169402, however US 2011/0169402 is not specific about the relationship between the thickness of the silver layers and the dielectric layers.

Similarly, US 2014/0347722, US 2018/0194675 and US 2018/0194676 describe a coating layer system with three silver layers, however, none of the documents describes the relationship between the silver layers and the dielectric layers specified in the present invention.

However, because sputtered dielectric layers are thicker and slower to deposit than, for example, sputtered metal layers such as silver, deposition of complex sequences of layers on a glass substrate often requires a large number of cathodes in the coating plant.

Initially, deposition of multiple complex coating stacks on a glass substrate was accomplished by installing expensive extensions to the coating line at the glass manufacturing plant to obtain enough cathodes suitable for depositing coating materials of the required thickness, quantity, etc.

This led, for example, to the installation of redundant pumping sections on extensions, which allows several reaction deposition processes to be launched sequentially. However, this is only achieved at great cost and often with enormous disruption, as the coating line usually needs to be shut down for extended periods of time to complete the required engineering work. Each new cathode and pumping section also requires power supply, vacuum pumps, conveyor sections, maintenance, instrumentation and control system integration. Such changes often lead to reconfigurations of logistics down the production line, and possibly even new construction work or building extensions. As requirements for multiple metal layers and/or more complex stacks become more common, these problems will increase.

In addition, while increasing the number of functional metal layers, such as silver, in a coating sequence helps optimize the solar control properties of the coated substrate, an increased number of functional metal silver layers adversely affects the light transmittance T _L of the glass substrate.

An additional effect of increasing the number of layers in a coated substrate is that it causes a change in the external color reflection of the coating when viewed from different angles.

Therefore, there is a need to provide a coated glass substrate that not only meets the requirements of the glass industry in terms of providing neutral color and effective light transmission, but which is also capable of providing the required thermal and solar control properties.

Thus, it is an object of the present invention to provide an improved transparent glass substrate that provides suitable optical and thermal properties.

That is, it is an object of the present invention to provide low emissivity and/or solar control coated glass substrates capable of withstanding normal environmental influences, such as storage, transportation and use, and which provide the desired substantially neutral color and optical properties.

It is a further object of the present invention to provide coated glass substrates with high selectivity, i.e., preferably greater than 2.0 (in which selectivity=ratio of light transmittance and g-value for a double glazed unit (GDU)) and low emissivity value , i.e., preferably less than 3%, which corresponds to low layer resistance.

For a double glazed unit (DGL) in a building produced with coated glass substrates, it is highly desirable that the coated glass has a uniform color upon external reflection. To achieve this and to demonstrate superior aesthetic appearance, it is important that the color change due to external reflection for the coated glass substrate when viewed from different viewing angles is minimal.

Since variations in thickness may occur during the manufacture of coated glass substrates, it is critical to minimize any color variations associated with changes in coating thickness to ensure a uniform color appearance to the building façade when installing a double glazing unit fitted with a coated glass substrate.

Therefore, in conclusion, it is an object of the present invention to solve the problems associated with the processes and products of the prior art that have been described in detail above, and to seek opportunities to provide cost-effective and commercially desirable coated glass substrates that meet the required optical properties in the glass industry , for example, in terms of turbidity, light transmission, and most importantly, color.

Therefore, according to a first aspect of the present invention, there is provided a transparent substrate comprising a multilayer coating stack, wherein the coating stack comprises:

i) n functional metal layers, m; And

ii) n plus 1 (n+1) dielectric layers, d, with dielectric layers located before and after each functional metal layer, and

wherein n is the total number of functional metal layers in the package, counted from the substrate, and greater than or equal to 3; And

wherein each dielectric layer contains one or more layers,

characterized by the fact that:

the geometric layer thickness for each functional metal layer in a multilayer coating package Gm is greater than the geometric layer thickness for each functional metal layer located before it in a multilayer coating package, i.e., Gm _i +1 ˃ Gm _i ,

where i is the position of the functional metal layer in a multilayer coating package, measured from the substrate, and at the same time

for each dielectric layer d located before and after each functional metal layer m, the optical layer thickness for each dielectric layer (opl _n ) is greater than or equal to the optical layer thickness for the dielectric layer (opl _n-1 ) located before it in the coating package, provided that:

the doubled optical thickness of the first dielectric layer (opl ₁ ) in the coating package is less than the optical thickness of the second dielectric layer (opl ₂ ) in the coating package, i.e., (2 × opl ₁ ) ˂ opl ₂ ; And

the doubled optical thickness of the layer of the last dielectric layer (opl _n+1 ) in the coating package is greater than the optical thickness of the layer of the penultimate dielectric layer (opl _n ), i.e., (opl _n ) ˂ (opl _n+1 ) × 2.

That is, for example, in relation to the present invention, when the multilayer coating stack contains three silver layers, the optical thickness of each dielectric layer can be expressed as:

(2 × opl ₁ ) ˂ opl ₂ ≤opl _n ˂ (opl _n+1 ×2),

where n is 3 and equal to the number of functional metallic silver layers.

When a multilayer plating stack contains four silver layers, the optical thickness of each dielectric layer can be expressed as:

(2 × opl ₁ ) ˂ opl ₂ ≤opl ₃ ≤opl _n ˂ (opl _n+1 ×2),

where n is 4 and equal to the number of functional metallic silver layers.

When a multilayer plating stack contains five silver layers, the optical thickness of each dielectric layer can be expressed as:

(2 × opl ₁ ) ˂ opl ₂ ≤opl ₃ ≤opl ₄ ≤opl _n ˂ (opl _n+1 ×2).

where n is 5 and equal to the number of functional metallic silver layers, and when the multilayer coating stack contains six silver layers, the optical thickness of each dielectric layer can be expressed as:

(2 × opl ₁ ) ˂ opl ₂ ≤opl ₃ ≤opl ₄ ≤opl ₅ ≤ opl _n ˂ (opl _n+1 ×2).

where n is 5 and equal to the number of functional metallic silver layers, etc.

In relation to the first aspect of the present invention, the functional metal layer may contain silver or gold, however, it is preferred that the functional metal layer contains silver.

It is preferred that the number of functional metal layers in the multilayer coating stack according to the present invention may be 3-6. It is more preferable that the number of functional metal layers in a multilayer coating stack is 4-6. However, it is most preferred that the number of functional metal layers in a multilayer coating stack be 4.

In relation to a transparent substrate coating stack according to the first aspect of the present invention, each dielectric layer may comprise one or more layers of material selected from: TiO _x , SnO ₂ , ZnO, ZnO:Al, ZrO _x , TiO _x , Nb ₂ O ₅ , Ta ₂ O ₅ , In ₂ O ₃ , Al ₂ O ₃ , SiO ₂ or their alloys or mixtures, such as, for example, ZnSnO _x , InSnO _x ; and/or (oxy)silicon nitride and/or (oxy)aluminum nitride and/or their alloys.

Between the functional metal layer and the subsequent dielectric layer in the coating stack, an absorbent layer selected from the group consisting of one or more of Ni, Cr, W, Nb, Ti, V or alloy and mixtures, for example NiCr or NiV, can be applied. It is preferred that the absorption layer be used to control the transmission of light and energy through the coating stack. However, in addition, the absorbent layer can also be used as a barrier layer.

In relation to the present invention, it is preferred that the coating package has an angular color shift of 0-60° for external reflection, when placed in a double glazed unit (DGL), Δa*, Δb*≤5. This means that for all visual angles up to 60°, the color shift to 0° visual angle for a* and b* will be less than 5.

It is more preferable for the coating package to have an angular color shift of 0-60° for external reflection when placed in a double glazed unit (DGL), with Δb*≤4. It is most preferred that the coating package has an angular color shift of 0-60° for external reflection when placed in a double glazed unit (DGL), with Δa*, Δb*≤3.

It is also preferred for the purposes of the present invention that the coating stack has a color shift for external reflection when placed in a double glazed unit (GDU) with thickness variations of 3% (or more) for a single dielectric or metal layer less than or equal to 5 for Δa* and less than or equal to 5 for Δb*. That is, if one dielectric or metal layer in a coating stack changes the target thickness by 3%, the observed color shift is less than 5 for a* and/or b*.

For purposes of the present invention, it is preferred that the coating stack has a color shift for external reflection when placed in a double glazed BDO unit, with thickness variations of 3% (or more) per dielectric or metal layer less than or equal to 4 for Δa * and less than or equal to 4 for Δb*.

With respect to the present invention, it is most preferred that the coating package have a color shift for external reflection when placed in a double glazed BDO unit, with thickness variations of 3% (or more) for one dielectric or metal layer, less than or equal to 3 for Δa* and less than or equal to 3 for Δb*.

In addition, in connection with the first aspect of the present invention, there is provided a transparent substrate in which the multilayer coating stack comprises:

- first dielectric layer, d ₁ ;

- first functional metal layer m ₁ ;

- second dielectric layer, d ₂ ;

- second functional metal layer m ₂ ;

- third dielectric layer, d ₃ ;

- third functional metal layer m ₃ ;

- fourth dielectric layer d ₄ .

In connection with this embodiment of the first aspect of the present invention, each of the first, second and third functional metal layer may comprise a layer of silver.

Also, in connection with this embodiment of the first aspect of the present invention, the first dielectric layer d1 closest to the glass substrate may comprise a titanium (Ti) oxide-based layer in series with the glass substrate or, alternatively, a first dielectric layer d1 closest to the glass substrate. substrate may comprise, in series with the glass substrate, a titanium oxide (Ti)-based layer and/or a zinc oxide (Zn)-based layer.

Additionally, the second dielectric layer d2 may comprise, sequentially from the glass substrate, a zinc oxide layer and a zinc oxide (Zn) and tin (Sn) layer.

The third dielectric layer d ₃ may preferably comprise, in series from the glass substrate, a zinc oxide (Zn) layer and/or a zinc oxide (Zn) and tin (Sn) layer. The third dielectric may also comprise a zirconium (Zr) oxide layer and/or a titanium oxide layer. The third dielectric layer may further comprise a zinc oxide layer located above the titanium oxide layer.

A NiCr absorbent layer may also be provided between the third metal layer and the fourth dielectric layer in the series. A NiCr layer may preferably be provided to control light transmission for a multi-layer coating stack.

Therefore, the multilayer coating stack may preferably comprise:

- first dielectric layer, d ₁ ;

- first functional metal layer m ₁ ;

- second dielectric layer, d ₂ ;

- second functional metal layer m ₂ ;

- third dielectric layer, d ₃ ;

- third functional metal layer m ₃ ;

- absorbing layer a ₁ ; And

- fourth dielectric layer d ₄ .

Additionally, the fourth dielectric layer may comprise a zinc oxide (Zn) layer and/or a zinc oxide (Zn) and tin (Sn) layer.

In addition, in connection with the first aspect of the present invention, there is provided a transparent substrate in which the multilayer coating stack comprises:

- first dielectric layer, d ₁ ;

- first functional metal layer m ₁ ;

- second dielectric layer, d ₂ ;

- second functional metal layer m ₂ ;

- third dielectric layer, d ₃ ;

- third functional metal layer m ₃ ;

- fourth dielectric layer d ₄ ;

- fourth functional metal layer m ₄ ; And

- fifth dielectric layer, d ₅ .

In connection with this embodiment of the first aspect of the present invention, the first, second, third and fourth functional metal layer may comprise a layer of silver.

Also, the first, second, third and fourth dielectric layers may be as described above, and the fifth dielectric layer may comprise a zinc oxide (Zn) layer and/or a zinc oxide (Zn) and tin (Sn) layer.

A NiCr absorbent layer may also be provided between the third metal layer and the fourth dielectric layer in the series. A NiCr layer may preferably be provided to control light transmission for a multi-layer coating stack. Likewise, a NiCr absorption layer may also be provided between the fourth metal layer and the fifth dielectric layer in the series.

Therefore, the multilayer coating stack may preferably comprise:

- first dielectric layer, d ₁ ;

- first functional metal layer m ₁ ;

- second dielectric layer, d ₂ ;

- second functional metal layer m ₂ ;

- third dielectric layer, d ₃ ;

- third functional metal layer m ₃ ;

- absorbent layer a ₁ ;

- fourth dielectric layer d ₄ ;

- fourth functional metal layer m ₄ ;

- absorbent layer a ₂ ;

- fifth dielectric layer, d ₅ .

Additionally, in relation to the first aspect of the present invention, each functional metal layer may have a thickness of 5-25 nm. It is more preferred that each functional metal layer may have a thickness of 6-23 nm. It is most preferred that each functional metal layer may have a thickness of 8-21 nm.

With respect to the first aspect of the present invention, it is preferred that the first dielectric layer d ₁ comprises, in sequential order from the glass substrate: a titanium oxide (Ti)-based layer and/or a zinc oxide (Zn)-based layer.

Also, in relation to the first aspect of the present invention, each of the second, third, fourth and fifth dielectric layers d ₂ , d ₃ , d ₄ and d ₅ may preferably comprise, in series from the glass substrate:

i) a zinc oxide (Zn)-based layer and/or a NiCr-based absorbent layer; And

ii) a layer based on zinc oxide (Zn) and tin (Sn) and/or tin oxide (Sn).

A NiCr-based absorbent layer may also be present in the coating package. The coating stack may preferably be in direct contact with the functional metal layer and may be used instead of a zinc oxide (Zn) based layer.

It is also preferred that the third dielectric layer d ₃ comprises a titanium oxide (Ti) based layer.

The fifth dielectric layer d ₅ may further comprise a layer based on zirconium oxide (Zr).

In addition, with respect to the first aspect of the present invention, it is preferable that the optical thickness of the first dielectric layer d ₁ be in the range of 30-70 nm. The optical thickness of the layer is equal to the product of the refractive index of the material (measured at a wavelength of 550 nm) and the geometric thickness of the material layer.

That is, with respect to the first aspect of the present invention, it is preferred that the double optical thickness of the first dielectric layer d ₁ be less than the optical thickness of the second dielectric layer d ₂ whereby, (2 xd ₁ ) ˂ d ₂ .

It is preferred that the optical thickness of the second dielectric layer d ₂ be in the range of 60-180 nm. It is also preferable that the optical thickness of the second dielectric layer d ₂ be less than or equal to the optical thickness of the third dielectric layer d ₃ , ie, d ₂ ≤d ₃ .

It is preferred that the optical thickness of the third dielectric layer d ₃ be in the range of 70-200 nm. It is also preferable that the optical thickness of the third dielectric layer d ₃ be less than or equal to the optical thickness of the fourth dielectric layer d ₄ ie, d ₃ ≤ d ₄ .

It is preferred that the optical thickness of the fourth dielectric layer d ₄ be in the range of 80-220 nm. It is preferred that the optical thickness of the fifth dielectric layer is in the range of 45-120 nm.

That is, with respect to the first aspect of the present invention, it is preferred that the optical thickness of the fourth dielectric layer d ₄ be less than twice the optical thickness of the fifth dielectric layer d ₅ , i.e., d ₄ ˂ (2 x d ₅ ).

According to a second aspect of the present invention, there is provided a double glazing unit including a transparent substrate with a multi-layer coating stack according to the first aspect of the present invention. It is preferred that all of the features described above in relation to the transparent substrate and multi-layer coating stack according to the first aspect of the present invention are also applied to the double glazing unit according to the second aspect of the present invention.

It is preferred for the first and second aspects of the present invention that the transparent substrate comprises glass, more preferably float glass.

Additionally, with respect to the double glazing unit according to the second aspect of the present invention, the double glazing unit may have a selectivity greater than or equal to 1.9. It is more preferable that the selectivity of the glass unit be greater than or equal to 2.0. It is most preferable that the selectivity of the glass unit be greater than or equal to 2.1. Selectivity is the ratio of the light transmittance and the g-value (total energy transmission) of a double glazing unit (GDU). Light transmittance and g-value are calculated according to EN 410, which is incorporated by reference in this work.

Also, in relation to the double glazing unit according to the second aspect of the present invention, it is preferable that the double glazing unit exhibits an angular dependence for external reflection a* and b* 0-60° less than or equal to 5; more preferably less than or equal to 4.0; and most preferably less than or equal to 3.0.

In addition, it is preferable that the double glazing unit according to the second aspect of the present invention further comprises a color shift with a thickness variation of 3% per layer, less than or equal to 5; more preferably less than or equal to 4.0; most preferably less than or equal to 3.0.

Embodiments of the present invention will be described herein by way of non-limiting examples and with reference to Figures 1-5, in which:

Figure 1 is a cross-section of a double glazed unit.

Figure 2 is a graphical representation of the angular reflection (in degrees) of a standard double glazed unit (GDU) versus b* and prepared with coated glass according to Example 1.

Figure 3 is a graphical representation of the angular reflection (in degrees) of a standard double glazed unit (GDU) versus b* prepared with coated glass according to Example 2.

Figure 4 is a graphical representation of the angular reflection (in degrees) of a standard double glazed unit (GDU) versus a* prepared with coated glass according to Example 3.

Figure 5 is a graphical representation of the angular reflection (in degrees) of a standard double glazed unit (GDU) versus a* prepared with coated glass according to Example 4.

In Figures 2 and 3, b* represents a color change from blue to yellow according to the CIE LAB color space, and in Figures 4 and 5, a* represents a color change from green to red according to the CIE LAB color space.

For the following examples, details of which are presented in Table 1, coatings were deposited on a standard 6 mm thick float glass panel, with approximately 90% light transmittance, using AC and/or DC magnetron sputtering devices (or pulsed DC devices), where The use of mid-frequency spray is suitable.

Dielectric layers of zinc oxide (Zn) and tin (Sn) were reactively sputtered from zinc-tin targets (Zn:Sn mass ratio approximately 50:50) in an argon/oxygen (Ar/O ₂ ) sputtering atmosphere.

Layers of titanium oxide (TiO _x ) were deposited from a target in the form of metallic titanium (Ti) or conductive titanium oxide (TiO _x ) in an argon/oxygen (Ar/O ₂ ) sputtering atmosphere.

Growth-accelerating ZnO:Al layers were sputtered from Al-doped zinc metal targets (aluminum (Al) content approximately 2 wt%) in an Ar/O ₂ sputtering atmosphere.

The functional layers, which in all examples consisted primarily of pure silver (Ag), were sputtered onto silver targets in an argon (Ar) sputtering atmosphere, without any addition of oxygen, and at a residual oxygen partial pressure of less than 10-4 mbar.

Al-doped zinc oxide barrier layers, also called ZAO, located above the silver-based functional layers, were sputtered from a conductive oxide target, a ZnO _x :Al target, in a pure argon (Ar) sputtering atmosphere, without the addition of oxygen.

NiCr layers (which can serve as absorber and/or barrier layers) located directly above the silver-based functional layers were sputtered from a NiCr metal target in a pure argon sputtering atmosphere.

Table 1

The table shows the geometric layer thicknesses in nm.

Layer Example 1 Example 2
(Comparative) Example 3
(Comparative) Example 4 1 TiO _x (19) TiO _x (33) TiO _x (22) TiO _x (22.5) 2 ZnO:Al(3.5) 3 Ag (9.3) Ag (14) Ag(11.3) Ag(8.9) 4 ZAO (2) ZAO (2) ZAO (2) ZAO (2) 5 ZnSnO _x (66) ZnSnO _x (73) ZnSnO _x (80) ZnSnO _x (66) 6 Ag (11.5) Ag (14) Ag (14.6) Ag (12) 7 ZAO (2) ZAO (2) ZAO (2) ZAO (2) 8 ZnSnO _x (31) ZnSnO _x (38) ZnSnO _x (25) ZnSnO _x (35) 9 TiO _x (29) TiO _x (30) TiO _x (33) TiO _x (30.5) 10 ZnO:Al(3.5) eleven Ag (15.6) Ag (14) Ag (15) Ag (14.5) 12 ZAO (2) ZAO (2) ZAO (2) NiCr (0.3) 13 ZnSnO _x (77) ZnSnO _x (63) ZnSnO _x (62) ZnSnO _x (79) 14 Ag (17.4) Ag (14) Ag(15.5) Ag(16.9) 15 ZAO (2) ZAO (2) ZAO (2) NiCr (0.8) 16 ZnSnO _x (41) ZnSnO _x (37) ZnSnO _x (17) ZnSnO _x (41) Substrate thickness 6 mm 6 mm 6 mm 6 mm Properties T _L 59 54 47 50 g-value 27 26 22 23 Selectivity 2.18 2.07 2.13 2.17 Δa*,
0-60° 1 3.9 12.1 2.2 Δb*,
0-60° 2.9 9.4 1.7 2.5 Δa*, 3% 2.5 6.2 10.6 2.9 Δb*, 3% 2.8 8.0 3.2 2.3

Table 1 provides details of the layer sequences for comparative coated glass panels and coated glass panels according to the present invention, along with the results for each layer sequence, with respect to:

light transmission (T _L ), g-value, selectivity, color shift Δa*, Δb* for angular measurement 0-60° and color shift Δa*, Δb* for a thickness change of 3%. All values are given for a double glazed unit (BDO). A color shift is always a shift in external reflection. For each example, layers were deposited sequentially onto a 6mm thick float glass panel, and are shown starting with the layer at the top of each column.

Color characteristics, i.e., color characteristics for each sample, were measured and presented using reliably established CIE LAB L*, a*, b* coordinates (as described for example in paragraphs [0030] and [0031] of the WO 2004 patent /063111A1, included in this work by reference).

In the following examples, in which the optical thickness of the coating layer is provided, the optical thickness of the layer is determined using a refractive index value of 2.45 for TiO _x , a refractive index of 2.07 for ZnO:Al (ZAO) and a refractive index of 2.07 for ZnSnO _x .

Example 1

The coating sequence described in Example 1 was prepared as follows. A first layer of titanium oxide (TiO _x ) was applied to a 6 mm float glass panel to form the first sequence of dielectric coatings with an optical layer thickness opl _{1 of} 46.6 nm. A layer of aluminum doped zinc oxide (ZnO:Al) with an optical thickness of 7.3 nm was then deposited on top of the titanium oxide (TiO _x ) layer. Consequently, the first dielectric layer is formed with an optical thickness opl ₁ of 53.9 nm. The first silver functional layer (Ag layer 1) was then deposited on top of the ZnO:Al layer to a coating thickness of 9.3 nm. An aluminum doped zinc oxide (ZAO) barrier layer with an optical layer thickness of 4.1 nm was then deposited onto the first silver functional layer (Ag layer 1), to protect the first silver functional layer from the subsequent second sequence of tin oxide and zinc oxide layer coatings. (ZnSnO _x ), deposited with an optical layer thickness of 136.6 nm. Consequently, a second sequence of dielectric layers was formed comprising a zinc tin oxide (ZnSnO _x ) layer and an aluminum doped zinc oxide (ZAO) layer with a combined optical layer thickness opl _{2 of} 140.7 nm. Next, a second silver functional layer (Ag layer 2) was deposited on top of the second dielectric layer, with a thickness of 11.5 nm. This was again followed by deposition of a second aluminum doped zinc oxide (ZAO) barrier layer, with an optical layer thickness of 4.1 nm, on top of the second silver functional layer (Ag layer 2). The second barrier layer of aluminum doped zinc oxide (ZAO) was then covered with a second layer of zinc tin oxide ( _ZnSnOx ) dielectric coating with an optical layer thickness of 64.2 nm. A second layer of titanium oxide (TiO _x ) was deposited to form a coating with an optical layer thickness of 71.1 nm. A second layer of aluminum doped zinc oxide (ZnO:Al) with an optical thickness of 7.3 nm was deposited on the titanium oxide to complete the third sequence of dielectric layers formed from an aluminum doped zinc oxide (ZAO) layer, a tin oxide layer, and a zinc oxide layer. (ZnSnO _x ), a zinc oxide layer (TiO _x ), and an aluminum doped zinc oxide layer (ZnO:Al) having an optical layer thickness opl _{3 of} 146.7 nm. Above the third sequence of dielectric layers, a third silver functional layer (Ag layer 3) with a thickness of 15.6 nm was then deposited. Then, a layer of aluminum doped zinc oxide (ZAO) with an optical layer thickness of 4.1 nm was deposited on top of the third silver functional layer (Ag layer 3), and a third layer of aluminum doped zinc oxide (ZAO) was deposited above the third layer of aluminum doped zinc oxide (ZAO). zinc and tin oxide ( _ZnSnOx ), with an optical layer thickness of 159.4 nm, forming a fourth sequence of dielectric layers, with a combined optical layer thickness, opl _4,163.5 nm. Above the third zinc tin oxide layer ( _ZnSnOx ) a fourth silver functional layer (Ag layer 4) was then deposited with a thickness of 17.4 nm. Then, above the fourth silver functional layer (Ag layer 4), a layer of aluminum doped zinc oxide (ZAO) was deposited with an optical layer thickness of 4.1 nm. Finally, above the fourth aluminum-doped zinc oxide (ZAO) layer, a fourth zinc tin oxide ( _ZnSnOx ) layer was deposited with an optical layer thickness of 82.8 nm, completing the fifth dielectric sequence with a combined optical layer thickness of opl ₅ 86. 9 nm.

Therefore, a layer sequence of e.g. 1 can be expressed in terms of optical layer thickness and geometric layer thickness for silver functional layers as:

glass/TiO _x , opl=46.6 nm/ZnO:Al, opl=7.3 nm/Ag ₁ 9.3 nm/ZAO, opl=4.1 nm/ZnSnO _x , opl=136.6 nm/Ag ₂ 11.5 nm/ZAO, opl=4.1 nm/ZnSnO _x , opl=64.2 nm/TiO _x , opl=71.1 nm/ZnO:Al, opl=7.3 nm/Ag ₃ 15, 6 nm/ZAO, opl=4.1 nm/ZnSnO _x 159.4 nm/Ag ₄ 17.4 nm/ZAO, opl=4.1 nm/ZnSnO _x , opl=82.8 nm,

The "opl" values expressed above and in relation to the following examples represent the optical thickness of the material layer and are derived from the product of the refractive index for the material and the geometric thickness of the material layer measured at a wavelength of 550 nm.

The optical layer thicknesses for each of the five dielectric layer sequences opl ₁ - opl ₅ can be summarized as:

opl ₁ =53.9 nm, opl ₂ =140.7 nm, opl ₃ =146.7 nm, opl ₄ =163.5 nm, opl ₅ =86.9 nm.

In addition, with respect to Example 1, the thickness of each dAg silver functional layer increases as the distance of the silver functional layer from the glass substrate increases. That is, for example, the thickness of the second silver functional layer dAg ₂ will be greater than the thickness of the first silver functional layer dAg ₁ .

Therefore, with regard to Example 1 and according to the present invention, the following relationships are satisfied:

i) regarding the thickness of the silver functional layers,

dAg ₁ ˂ dAg ₂ ˂ dAg ₃ ˂ dAg ₄ ; And

ii) in relation to the thickness of the combined sequence of dielectric layers before, after and between each of the silver functional layers,

(opl ₁ ×2) ˂ opl ₂ ˂ opl ₃ ˂ opl ₄ ˂ (opl ₅ ×2)

A double glazing unit (DGL) (1), as illustrated in Figure 1, was prepared using a glass sheet (2) coated (5) with a thickness of 6 mm as described in Example 1. That is, sheet (2) of coated float glass, 6 mm thick, as detailed in Example 1, was assembled with a second, uncoated sheet (3) of 4 mm thick float glass. The two sheets of glass (2, 3) were arranged so that the coated side (5) of the coated glass sheet (2) faced the gap (8) (referred to as position two in the BDO when installed), i.e., the coated glass sheet (2) is closer to the outside environment (10) than the uncoated glass sheet (3), forming a thermally insulated double glazing unit. The glass sheets were installed with a gap distance between them equal to 16 mm, and the gap (8) of the gap was filled 90% with argon gas and 10% with air. Thus, the uncoated surface (4) of the coated glass sheet (2) was represented by position 1, and the two uncoated surfaces (6) and (7) of the second glass sheet (3) were represented by positions 3 and 4, respectively. glazings with low-e coating under position 2 were measured in accordance with EN 410. The results are presented in Table 2:

table 2

Parameter Measured value Light transmittance (T _L ) 59 G-value 27 Selectivity 2.18 Δa*, 0-60° 1.0 Δb*, 0-60° 2.9 Δa*, 3% 2.5 Δb*, 3% 2.8

In Table 2, the selectivity value is equal to the ratio of the light transmittance and the g-value for a double glazed unit, in which each value is calculated using EN 410, which is incorporated herein by reference.

Regarding the difference in external reflection of the BDO prepared with the coating of Example 1 according to the present invention for a visual angle of 0-60°, with respect to a* and b*, it was found that Δa* = 1.0 and Δb* = 2, 9. A graphical representation of the change in b* as a function of viewing angle, eg 1, shown in Figure 2 indicates that the coating used in Example 1 is within the required limits.

Also, in relation to BDO prepared with a coating according to Example 1 according to the present invention, color shifts with a change in thickness of 3% are for Δa* = 2.5 and Δb* = 2.8. That is, the values for Δa* and Δb* for BDO prepared using the coating of the present invention are within the acceptable limit of 5, and are also within the preferred limit of 4, and are even within the particularly preferred limit of 3.

Comparative Example 2

The coating sequence described in Example 2 was prepared as follows. A first layer of titanium oxide (TiO _x ) was deposited onto a 6 mm float glass panel to form the first sequence of opl ₁ dielectric coatings, with an optical layer thickness of 80.9 nm. On top of the titanium oxide (TiO _x ) layer, the first silver functional layer (Ag layer 1) was then deposited, achieving a coating thickness of 14 nm. Next, an aluminum doped zinc oxide (ZAO) barrier layer with an optical layer thickness of 4.1 nm was applied to the first silver functional layer (Ag layer 1) to isolate the first silver functional layer from the subsequent second sequence of tin oxide coating layers and zinc (ZnSnO _x ), with an optical layer thickness of 151.1 nm. Thus, a second sequence of dielectric layers was formed comprising a zinc tin oxide (ZnSnO _x ) layer and an aluminum doped zinc oxide (ZAO) layer with a combined optical layer thickness of 155.2 nm. Then, above the second dielectric layer, a second silver functional layer (Ag layer 2), with a thickness of 14 nm, was deposited. Then, above the second silver functional layer (Ag layer 2), a second barrier layer of aluminum doped zinc oxide (ZAO) was again deposited with an optical layer thickness of 4.1 nm. A second aluminum-doped zinc oxide (ZAO) barrier layer was then coated with a second zinc tin oxide (ZnSnO _x ) dielectric coating layer with an optical layer thickness of 78.7 nm. A second titanium oxide (TiO _x ) layer was deposited, forming a coating with an optical layer thickness of 73.5 nm, completing a third sequence of opl ₃ dielectric layers formed from an aluminum doped zinc oxide (ZAO) layer, a zinc tin oxide layer ( ZnSnO _x ) and a zinc oxide layer (TiO _x ) and having a combined optical layer thickness of 156.3 nm. Above the third sequence of dielectric layers, a third silver functional layer (Ag layer 3) with a thickness of 14 nm was then deposited. Then, a layer of aluminum doped zinc oxide (ZAO) with an optical layer thickness of 4.1 nm was deposited on top of the third silver functional layer (Ag layer 3), and a third layer of aluminum doped zinc oxide (ZAO) was deposited above the third layer of aluminum doped zinc oxide (ZAO). tin oxide ( _ZnSnOx ) with an optical layer thickness of 130.4 nm, forming a fourth sequence of dielectric layers, opl ₄ , with a combined optical layer thickness of 134.6 nm. Then, above the third layer of zinc oxide (ZnSnO _x ), a fourth silver functional layer (Ag layer 4) with a thickness of 14 nm was deposited. Then, above the fourth silver functional layer (Ag layer 4), a layer of aluminum doped zinc oxide (ZAO) was deposited with an optical layer thickness of 4.1 nm. Finally, above the fourth aluminum-doped zinc oxide (ZAO) layer, a fourth zinc tin oxide ( _ZnSnOx ) layer was deposited with an optical layer thickness of 76.6 nm, completing the fifth dielectric sequence, opl ₅ , with a combined optical layer thickness 80.7 nm.

Thus, a sequence of layers, for example 2, can be expressed as:

glass/TiO _x , opl=80.9 nm/Ag 14 nm/ZAO, opl=4.1 nm/ZnSnO _x , opl=151.2 nm/Ag 14 nm/ZAO, opl=4.1 nm/ZnSnO _x , opl=78.7 nm/TiO _x , opl=73.5 nm/Ag 14 nm/ZAO, opl=4.1 nm/ZnSnO _x 130.4 nm/Ag 14 nm/ZAO, opl=4.1 nm /ZnSnO _x , opl=76.6 nm,

The optical layer thickness for each of the five dielectric layer sequences opl ₁ -opl ₅ in Comparative Example 2 can be summarized as:

opl ₁ =80.9 nm, opl ₂ =155.2 nm, opl ₃ =156.3 nm, opl ₄ =134.5 nm, opl ₅ =80.7 nm.

Therefore, for Comparative Example 2, the following relationship regarding the thicknesses of the silver functional layers is not satisfied:

dAg ₁ ˂ dAg ₂ ˂ dAg ₃ ˂ dAg ₄ .

Instead, with respect to the thickness of the silver functional layers for Comparative Example 2, the following relationship holds:

dAg ₁ =dAg ₂ =dAg ₃ =dAg ₄ .

That is, the thickness of each silver functional layer is equal for all layers.

Also, with respect to the thickness of the combined sequence of dielectric layers before, after and between each of the silver functional layers, for Comparative Example 2, the ratio is:

(opl ₁ ×2) ˂ opl ₂ ˂ opl ₃ ˂ opl ₄ ˂ (opl ₅ ×2)

is not satisfied, but instead, twice the optical thickness of the first dielectric layer (opl ₁ ×2) will be greater than the optical thickness of the second dielectric layer opl ₂ ; and the combined optical thickness of the opl ₃ layer is greater than the combined optical thickness of the opl ₄ layer.

Therefore, Comparative Example 2 has the following relationship between the combined optical thickness of the layers:

(opl ₁ ×2) ˃ opl ₂ ˂ opl ₃ ˃ opl ₄ ˂ (opl ₅ ×2)

A double glazing unit (DGL) (1), as illustrated in Figure 1, was prepared using a 6 mm glass sheet (2) with a coating (5) as described in Comparative Example 2. That is, a float glass sheet (2) coated with a thickness of 6 mm, as detailed in Example 2, was assembled with a second, uncoated sheet (3) of float glass, thickness 4 mm. The two sheets of glass (2, 3) were arranged so that the coated side (5) of the coated glass sheet (2) faced the gap (8) (referred to as position two in the BDO when installed), and so that the coated glass sheet (2) was closer to the external environment (10) than the uncoated glass sheet (3), forming a thermally insulated double glazing unit. The glass sheets were placed so that the distance between them was 16 mm, and the gap (8) of the gap was filled 90% with argon gas and 10% with air. Thus, the uncoated surface (4) of the coated glass sheet (2) was represented by position 1, and the two uncoated surfaces (6) and (7) of the second glass sheet (3) were represented by positions 3 and 4, respectively. The glazings with low-emissivity coating according to Comparative Example 2 under item 2 were measured in accordance with EN 410. The results are presented in Table 3:

Table 3

Parameter Measured value Light transmittance (T _L ) 54 G-value 26 Selectivity 2.07 Δa*, 0-60° 3.9 Δb*, 0-60° 9.4 Δa*, 3% 6.2 Δb*, 3% 8.0

In Table 3, the selectivity value is equal to the ratio of the light transmittance and the g-value for a double glazed unit, in which each value is calculated using EN 410, incorporated herein by reference.

It was found that the difference in external reflection of BDO prepared with the coating according to Comparative Example 2 for a visual angle of 0-60°, with respect to a* and b*, was Δa* = 3.9 and Δb* = 9.4. A graphical representation of the change in b* depending on the viewing angle, for example, 2 is shown in Figure 3.

Also, for BDO prepared with the coating of Example 2 (not in accordance with the present invention), color shifts with a thickness change of 3% are presented for Δa* = 6.2 and Δb* = 8.0. That is, the values for Δa* and Δb* for BDO using the coating detailed in Comparative Example 2 greatly exceed even the acceptable limit of 5.

Example 3

The coating sequence described in Comparative Example 3 was prepared as follows. A first layer of titanium oxide (TiO _x ) was applied to a 6 mm float glass panel to form the first sequence of dielectric coatings with an optical layer thickness opl ₁ of 53.9 nm. A first silver functional layer (Ag layer 1) was then deposited on top of the titanium oxide (TiO _x ) layer to achieve a coating thickness of 11.3 nm. A barrier layer was then deposited onto the first silver functional layer (Ag layer 1) to isolate the first silver functional layer from the subsequent second sequence of zinc oxide ( _ZnSnOx ) layers deposited at an optical layer thickness of 165.6 nm. aluminum doped zinc oxide (ZAO), with an optical layer thickness of 4.1 nm. Thus, a second sequence of dielectric layers was formed containing a zinc tin oxide (ZnSnO _x ) layer and an aluminum doped zinc oxide (ZAO) layer with a combined optical layer thickness opl _{2 of} 169.7 nm. Then, above the second dielectric layer, a second silver functional layer (Ag layer 2), with a thickness of 14.6 nm, was deposited. This was again followed by a second aluminum doped zinc oxide (ZAO) barrier layer with an optical layer thickness of 4.1 nm deposited above the second silver functional layer (Ag layer 2). A second aluminum-doped zinc oxide (ZAO) barrier layer was then coated with a second zinc tin oxide (ZnSnO _x ) dielectric coating layer, achieving an optical layer thickness of 51.8 nm. A second layer of titanium oxide (TiO _x ) was deposited, forming a coating with an optical layer thickness of 80.9 nm, completing a third sequence of dielectric layers formed from an aluminum doped zinc oxide (ZAO) layer, a zinc tin oxide layer (ZnSnO _x ) and a layer of zinc oxide (TiO _x ), having an optical layer thickness opl ₃ of 136.8 nm. Above the third sequence of dielectric layers, a third silver functional layer (Ag layer 3) with a thickness of 15 nm was then deposited. Then, a layer of aluminum doped zinc oxide (ZAO) with an optical layer thickness of 4.1 nm was deposited on top of the third silver functional layer (Ag layer 3), and a third layer of aluminum doped zinc oxide (ZAO) was deposited above the third layer of aluminum doped zinc oxide (ZAO). zinc and tin oxide ( _ZnSnOx ), with an optical layer thickness of 128.3 nm, to form a fourth sequence of dielectric layers with a combined optical layer thickness, opl _4,132.4 nm. Then, above the third layer of zinc oxide (ZnSnO _x ), a fourth silver functional layer (Ag layer 4), with a thickness of 15.5 nm, was deposited. Then, above the deposited fourth silver functional layer (Ag layer 4), a layer of aluminum doped zinc oxide (ZAO) was deposited with an optical layer thickness of 4.1 nm. Finally, above the fourth aluminum doped zinc oxide (ZAO) layer, a fourth zinc tin oxide ( _ZnSnOx ) layer was deposited with an optical layer thickness of 31.1 nm, completing the fifth dielectric sequence, with a combined optical layer thickness of opl ₅ 35 ,2 nm.

Thus, the layer sequence for Comparative Example 3 can be expressed as:

glass/TiO _x , opl=53.9 nm/Ag 11.3 nm/ZAO, opl=4.1 nm/ZnSnO _x , opl=165.6 nm/Ag 14.6 nm/ZAO, opl=4.1 nm/ZnSnO _x , opl=51.8 nm/TiO _x , opl=80.9 nm/Ag 15 nm/ZAO, opl=4.1 nm/ZnSnO _x 128.3 nm/Ag 15.5 nm/ZAO, opl=4.1 nm/ZnSnO _x , opl=31.1 nm.

The combined optical layer thicknesses for each of the five dielectric layer sequences opl ₁ -opl ₅ can be summarized as:

opl ₁ =53.9 nm, opl ₂ =169.7 nm, opl ₃ =136.8 nm, opl ₄ =132.4 nm, opl ₅ =35.2 nm.

In relation to silver functional layers, the following relationship holds:

dAg ₁ ˂ dAg ₂ ˂ dAg ₃ ˂ dAg ₄

However, with respect to the thickness of the combined sequence of dielectric layers before, after and between each of the silver functional layers, the ratio in question is, for example, 1, namely,

(opl ₁ ×2) ˂ opl ₂ ˂ opl ₃ ˂ opl ₄ ˂ (opl ₅ ×2)

does not hold for Comparative Example 3, but instead, the combined optical thickness for the second sequence of dielectric layers opl ₂ will be less than twice the combined optical thickness of the opl ₁ layer; the combined optical thickness of the opl ₂ layer will be greater than the combined optical thickness of the opl ₃ layer; and the combined optical thickness of the opl ₃ layer will be greater than the combined optical thickness of the opl ₄ layer. That is, for Comparative Example 3 the following relationship is observed for the combined optical thickness of the opl ₁ -opl ₅ layer:

(opl ₁ ×2) ˃ opl ₂ ˃ opl ₃ ˃ opl ₄ ˂ (opl ₅ ×2)

A double glazing unit (DGL) (1), as illustrated in Figure 1, was prepared using a 6 mm glass sheet (2) coated with (5) as described in Comparative Example 3. That is, sheet (2) of coated float glass, 6 mm thick, as detailed in Example 3, was assembled with a second uncoated sheet (3) of 4 mm thick float glass. The two sheets of glass (2, 3) were arranged so that the coated side (5) of the coated glass sheet (3) faced the gap (8) (called position two in the BDO when installed), i.e., the coated glass the sheet (5) is closer to the external environment (10) than the uncoated glass sheet (3), forming a thermally insulated double glazing unit. The glass sheets were placed with a gap of 16 mm between them, and the gap (8) of the gap was filled 90% with argon gas and 10% with air. Thus, the uncoated surface (4) of the coated glass sheet (2) was represented by position 1, and the two uncoated surfaces (6) and (7) of the second glass sheet (3) were represented by positions 3 and 4, respectively. glazings with low-emissivity coating from Comparative Example 3 under item 2 were measured in accordance with EN 410. The results are presented in Table 4:

Table 4

Parameter Measured value Light transmittance (T _L ) 47 G-value 22 Selectivity 2.13 Δa*, 0-60° 12.1 Δb*, 0-60° 1.7 Δa*, 3% 10.6 Δb*, 3% 3.2

In Table 4, the selectivity value is equal to the ratio of the light transmittance and the g-value for a double glazed unit, in which each value is calculated using EN 410, incorporated herein by reference.

It was found that the difference in external reflection of BDO prepared with the coating according to Comparative Example 3 for a visual angle of 0-60°, with respect to a* and b*, was Δa* = 12.1 and Δb* = 1.7. A graphical representation of the change in a* depending on the viewing angle, for example, 3 is shown in Figure 4.

Also, in relation to BDO prepared with a coating according to Example 3, color shifts with a change in thickness of 3% are Δa* = 10.6 and Δb* = 3.2.

That is, the Δa* values for the BDO using the coating detailed in Comparative Example 3 greatly exceed even the acceptable limit of 5.

Example 4

The coating sequence described in Example 4 was prepared as follows. A first layer of titanium oxide (TiO _x ) was applied to a 6 mm float glass panel to form the first sequence of dielectric coatings, with an optical layer thickness opl ₁ of 55.1 nm. A first silver functional layer (Ag layer 1) was then deposited on top of the titanium oxide (TiO _x ) layer to achieve a coating thickness of 8.9 nm. A zinc oxide barrier layer was then deposited onto the first silver functional layer (Ag layer 1) to isolate the first silver functional layer from the subsequent second sequence of zinc oxide ( _ZnSnOx ) coating layers deposited at an optical layer thickness of 132.5 nm. doped with aluminum (ZAO), with an optical layer thickness of 4.1 nm. Thus, a second sequence of dielectric layers was formed containing a zinc tin oxide (ZnSnO _x ) layer and an aluminum doped zinc oxide (ZAO) layer with a combined optical layer thickness opl _{2 of} 136.6 nm. Then, above the second dielectric layer, a second silver functional layer (Ag layer 2), with a thickness of 12 nm, was deposited. This was again followed above the second silver functional layer (Ag layer 2) by deposition of an additional aluminum doped zinc oxide (ZAO) barrier layer with an optical layer thickness of 4.1 nm. The aluminum doped zinc oxide (ZAO) layer was then coated with a zinc tin oxide ( _ZnSnOx ) layer to achieve a thickness of 68.3 nm. A 74.7 nm thick layer of zinc oxide (TiO _x ) was then deposited to form a third sequence of opl ₃ dielectric layers, with a combined optical layer thickness of 147.1 nm. Above the third sequence of dielectric layers, a third silver functional layer (Ag layer 3), with a thickness of 14.5 nm, was then deposited. An absorbing layer of nichrome with a thickness of 0.3 nm was then applied to the silver layer, reducing the transmittance of the coating. Above the NiCr layer, a third layer of tin oxide ( _ZnSnOx ) was deposited with an optical layer thickness of 163.5 nm, forming a fourth sequence of dielectric layers, with a combined effective optical layer thickness of opl _4,163.5 nm. Above the third zinc tin oxide (ZnSnO _x ) layer, a fourth silver functional layer (Ag layer 4) was then deposited with a thickness of 16.9 nm. Then, above the fourth layer of silver, a layer of nichrome was deposited, with an optical layer thickness of 0.8 nm. Finally, a fourth zinc tin oxide (ZnSnO _x ) layer was deposited with an optical layer thickness of 84.9 nm, completing the fifth dielectric sequence, with a combined effective optical layer thickness opl ₅ of 86.9 nm.

Thus, a layer sequence, for example 1, can be expressed in terms of optical layer thickness and geometric layer thickness for silver functional layers as:

glass/TiO _x , opl=55.1 nm/Ag 8.9 nm/ZAO, opl=4.1 nm/ZnSnO _x , opl=132.5 nm/Ag 12 nm/ZAO, opl=4.1 nm/ ZnSnO _x , opl=68.3 nm/TiO _x , opl=74.7 nm/Ag 14.5 nm/NiCr 0.3 nm/ZnSnO _x 163.5 nm/Ag 16.9 nm/NiCr 0.8 nm /ZnSnO _x , opl=84.9 nm.

The optical layer thicknesses for each of the five dielectric layer sequences opl ₁ - opl ₅ can be summarized as:

opl ₁ =55.1 nm, opl ₂ =136.6 nm, opl ₃ =147.1 nm, opl ₄ =163.5 nm, opl ₅ =84.9 nm.

In addition, with respect to Example 4, the thickness of each dAg silver functional layer increases with increasing distance from the silver functional layer to the glass substrate. That is, for example, the thickness of the second silver functional layer dAg ₂ will be greater than the thickness of the first silver functional layer dAg ₁ .

Therefore, in relation to Example 4 according to the present invention, the following relationships are satisfied:

i) regarding the thicknesses of the silver functional layers,

dAg ₁ ˂ dAg ₂ ˂ dAg ₃ ˂ dAg ₄ ; And

ii) in relation to the thickness of the combined sequence of dielectric layers before, after and between each of the silver functional layers,

(opl ₁ ×2) ˂ opl ₂ ˂ opl ₃ ˂ opl ₄ ˂ (opl ₅ ×2)

A double glazing unit (DGU) (1), as illustrated in Figure 1, was prepared using a 6 mm glass sheet (2) coated with (5) as described in Example 4. That is, sheet (2) of The 6 mm thick coated float glass as detailed in Example 4 was assembled with a second, uncoated 4 mm thick float glass sheet (3). The two sheets of glass (2, 3) were arranged so that the coated side (5) of the coated glass sheet (3) faced the gap (8) (called position two in the BDO when installed), i.e., the coated glass the sheet (5) is closer to the external environment (10) than the uncoated glass sheet (3), forming a thermally insulated double glazing unit. The glass sheets were arranged so that the gap between them was 16 mm, and the gap (8) of the gap was filled 90% with argon gas and 10% with air. Thus, the bare surface (4) of the coated glass sheet (2) is present at position 1, and the two bare surfaces (6) and (7) of the second glass sheet (3) are present at positions 3 and 4, respectively. The properties of double glazing with low-e coating under position 2 were measured in accordance with EN 410. The results are presented in Table 5:

Table 5

Parameter Measured value Light transmittance (T _L ) 50 G-value 23 Selectivity 2.17 Δa*, 0-60° 2.2 Δb*, 0-60° 2.5 Δa*, 3% 2.9 Δb*, 3% 2.3

In Table 5, the selectivity value is equal to the ratio of the light transmittance and the g-value for a double glazed unit, in which each value is calculated using EN 410, incorporated herein by reference.

It was found that the difference in external reflectance of BDO prepared with the coating according to Comparative Example 4 for a visual angle of 0-60°, with respect to a* and b*, was Δa* = 2.2 and Δb* = 2.5. A graphical representation of the change in a* depending on the viewing angle, for example, 4 is shown in Figure 5.

Also, in relation to BDO prepared with a coating according to Example 4, color shifts with a change in thickness of 3% are Δa* = 2.9 and Δb* = 2.3. That is, the values for Δa* and Δb* for BDO prepared using the coating of Example 4 according to the present invention are within the acceptable limit 5, as well as within the preferred limit 4, and even within the particularly preferred limit 3.

Review of results

Thus, from the above results, it is clear that the coated glass sheets prepared according to the present invention (ie, Examples 1 and 4) provide good solar control performance, with a high selectivity of 2.18-2.17. Also, both Examples 1 and 4 show a slight change in external color at different viewing angles when placed on the façade. For both Examples, it is preferred that the color change under different viewing angles, when placed in a double glazing unit, have a value of Δa* and Δb* of less than 3.0.

With regard to the production of double glazed units (DGUs), an important advantage associated with the present invention is the ability to produce DGUs that exhibit little color change with changing thickness of the coating layer. For both Examples 1 and 4, a change of less than 3 was observed for both Δa* and Δb* when the thickness of the fourth dielectric layer of the coating stack changed by 3%.

In contrast, in Comparative Example 2, where all the silver layers had the same thickness, and the relationship for the optical thicknesses for each of the required dielectric layers for the present invention is not satisfied, the selectivity is 2.07, and the color shift for the coated substrate at different viewing angles ( 0-60°), when forming the BDO, is more than 5 for b*, and in fact Δb* = 9.4. The color change with a 3% change in thickness for the second dielectric layer in Example 2 is also more than 5, respectively, with values of Δa* = 6.2 and Δb* = 8.0.

In Comparative Example 3, the required ratio for the optical thickness for the dielectric layers according to the present invention is again not satisfied. Instead, the optical layer thicknesses for the dielectric layers in Example 3, instead of increasing, decrease away from the glass substrate. In addition, the selectivity is 2.13 and the color shift at different viewing angles (0-60°) for the BDO formed with coated glass according to Example 3 is more than 5 for a*, and in fact, Δa* = 12.1. Finally, the color change recorded with a 3% thickness change for the fourth dielectric layer in Example 3 for a* is also greater than 5, with a value of Δa* = 10.6.

Claims (44)

1. Window glass containing a multi-layer coating package, wherein said coating package contains: i) n functional metal layers, m; And ii) n plus 1 (n+1) dielectric layers, d, with dielectric layers located before and after each functional metal layer, and wherein n is the total number of functional metal layers in said package, counted from the substrate, and greater than or equal to 4; And wherein each dielectric layer contains one or more layers, characterized by the fact that: the geometric layer thickness for each functional metal layer in a multilayer coating package Gm is greater than the geometric layer thickness for each functional metal layer located before it in a multilayer coating package, i.e., Gm _i+1 ˃ Gm _i , where i is the position of the functional metal layer in the multilayer coating package, measured from the substrate, and at the same time, for each dielectric layer d located before and after each functional metal layer m, the optical layer thickness for each dielectric layer (opl _n ) is greater than or equal to the optical layer thickness for the dielectric layer (opl _n-1 ) located before it in said coating package , provided that: the doubled optical layer thickness of the first dielectric layer (opl ₁ ) in said coating package is less than the optical layer thickness of the second dielectric layer (opl ₂ ) in said coating package, i.e., (2 × opl ₁ ) ˂ opl ₂ ; And the doubled optical thickness of the layer of the last dielectric layer (opl _n+1 ) in the mentioned coating package is greater than the optical thickness of the layer of the penultimate dielectric layer (opl _n ), i.e., (opl _n ) ˂ (opl _n+1 ) × 2; And wherein the functional metal layer contains silver; And the number of functional metal layers n in a multilayer coating package ranges from 4 to 6. 2. Window glass according to claim 1, in which the number of functional metal layers in the multilayer coating package is 4; and/or each dielectric layer contains one or more layers of material selected from: TiO _x , SnO ₂ , ZnO, ZAO, ZnO:Al, ZrO _x , TiO _x , Nb ₂ O ₅ , Ta ₂ O ₅ , In ₂ O ₃ , Al ₂ O ₃ , SiO ₂ or their alloys or mixtures, including ZnSnO _x , InSnO _x , and/or silicon (oxy)nitride and/or aluminum (oxy)nitride and/or alloys thereof. 3. Window glass according to claim 1 or 2, in which the multilayer coating package contains: first dielectric layer, d ₁ ; first functional metal layer m ₁ ; second dielectric layer, d ₂ ; second functional metal layer m ₂ ; third dielectric layer, d ₃ ; third functional metal layer m ₃ ; fourth dielectric layer d ₄ ; fourth functional metal layer m ₄ ; fifth dielectric layer, d ₅ . 4. Window glass according to any of the previous paragraphs, in which each functional metal layer has a thickness of 5-25 nm. 5. Window glass according to claim 3 or 4, in which the first dielectric layer d ₁ contains, in succession from the glass substrate: a layer based on titanium oxide (Ti) and/or a layer based on zinc oxide (Zn). 6. Window glass according to paragraphs. 3, 4 or 5, in which each of the second, third, fourth and fifth dielectric layers d ₂ , d ₃ , d ₄ and d ₅ contains in series from the glass substrate: i) zinc oxide (Zn) based layer; And ii) a layer based on zinc oxide (Zn) and tin (Sn) and/or tin oxide (Sn). 7. Window glass according to claim 6, in which the third dielectric layer d ₃ additionally contains a layer based on titanium oxide (Ti). 8. Window glass according to any one of paragraphs. 3-7, in which the fifth dielectric layer d ₅ further comprises a layer based on zirconium oxide (Zr). 9. Window glass according to any one of paragraphs. 3-8, in which the optical thickness of the first dielectric layer d ₁ is in the range of 30-70 nm; and/or in which the optical layer thickness of the second dielectric layer d ₂ is in the range of 60-180 nm; and/or in which the optical layer thickness of the third dielectric layer d ₃ is in the range of 70-200 nm; and/or in which the optical layer thickness of the fourth dielectric layer d ₄ is in the range of 80-220 nm; and/or in which the optical thickness of the fifth dielectric layer d ₅ is in the range of 45-120 nm. 10. Window glass according to any one of paragraphs. 3-9, wherein said coating package further comprises one or more NiCr-based layers. 11. The window glass of claim 10, wherein one or each NiCr-based layer is in direct contact with one or more silver functional layers. 12. A block with double glazing, including window glass with a multilayer coating package according to any one of paragraphs. 1-11. 13. A block with double glazing according to claim 12, in which the angular dependence for external reflection a* and b* 0-60° is less than or equal to 5; more preferably less than or equal to 4.0; most preferably less than or equal to 3.0. 14. Double glazing block according to claim 12 or 13, additionally having a color shift with a thickness change of 3% for one layer, less than or equal to 5; more preferably less than or equal to 4.0; most preferably less than or equal to 3.0. 15. Block with double glazing according to paragraphs. 12, 13 or 14, further having a selectivity greater than or equal to 1.9, more preferably greater than or equal to 2.0, and most preferably greater than or equal to 2.1.