1. FIELD OF THE INVENTION

[0001] The invention relates to a multiple glazing that comprises a vacuum insulating glazing unit wherein one or more of its glass panes is (are) further laminated, to provide thermal insulation as well as safety, security and/or acoustic performance.

2. BACKGROUND OF THE INVENTION

[0002] Multiple glazing such as double glazing or even triple glazing, is a very traditional answer to provide thermal insulation. Double glazing typically comprises two glass panes coupled along their periphery by a peripheral spacer creating an internal space sealed by a peripheral edge seal. Said peripheral spacer maintains a certain distance between the two glass panes. In general, said internal space is filled with air and/or an inert gas, to further lower the heat transfer and/or to reduce the sound transmission.

[0003] Therefore, the skilled person in that art would consider replacing one of the glass panes of such multiple glazing by a vacuum insulating glazing unit to provide superior thermal performance. EP860406A discloses a double glazing comprising one or two vacuum insulating glazing unit(s). However such configuration generates other technical problems. Indeed, it was expected that the vacuum insulating glazing unit would behave mechanically within a multiple glazing as a single pane since the internal volume of the vacuum insulating glazing unit is very thin and since both glass panes are strongly coupled by the hermetically bonding seal. However, it has been surprisingly found that the vacuum insulating glazing unit within a multiple glazing demonstrates very different mechanical and thermal performances.

[0004] Vacuum-insulating glazing units are recommended because of their high-performance thermal insulation. A vacuum-insulating glazing unit is typically composed of at least two glass panes separated by an internal volume in which a vacuum has been generated. In general, in order to achieve a high- performance thermal insulation (Thermal transmittance, Ug, being Ug<1.2 W/m ² K) the absolute pressure inside the glazing unit is typically 0.1 mbar or less and generally at least one of the two glass panes is covered with a low-emissivity layer. To obtain such a pressure inside the glazing unit, a hermetically bonding seal is placed on the periphery of the two glass panes and vacuum is generated inside the glazing unit by virtue of a pump. To prevent the glazing unit from caving in under atmospheric pressure (due to the pressure difference between the interior and exterior of the glazing unit), discrete spacers are placed between the two glass panes. [0005] Vacuum-insulating glazing units are carefully dimensioned to resist to different external loads. A major load to be considered is the load induced by a temperature difference between exterior and interior environments. Indeed, the glass pane facing the interior environment, takes up a temperature similar to the temperature of the interior environment and the glass pane facing the exterior environment, takes up a temperature similar to the temperature of the exterior environment. In most stringent weather conditions, the difference between the interior and exterior temperatures can reach 40°C and more. The temperature difference between the interior and exterior environments may cause stress inside the glass panes and in some severe cases, may lead to fracture of the vacuuminsulating glazing unit. Therefore, it is critical to control the level of thermal induced stress.

[0006] Furthermore, it is often required that the multiple glazing also brings safety, security and/or acoustic performances. Hence, one or more of the glass panes of the multiple glazing can typically be laminated. It can be necessary that the multiple glazing unit meets the safety requirements of the European Standard EN12600. European Standard EN356 deals with security glazing designed to resist to actions of force by delaying access of objects and/or persons to a protected space for a short period of time. It is well known in the art to use laminated glass to obtain such safety and security performances : two or more glass panes are bonded together by a durable plastic interlayer, which enables the glass to strongly resist penetration by impacting objects. If the glass would nevertheless break, it will tend to remain in its frame, minimizing the risk of injury from sharp edges and flying or falling glass particles. Therefore, laminated glass is usually used for applications such as protection against explosions, protection against burglary, for bullet resistance, in glass floors or stairs, protection from fallout of broken glass from building facades, earthquake resistance,... Lamination can also be applied to vacuum insulating glazing units. For example, EP 1 544 180 discloses a vacuum-insulating glazing unit wherein one of the glass panes has an outer surface bonded to a plate-shaped member via an adhesive layer to minimize distortions of reflected images while maintaining a low coefficient of heat transmission.

[0007] None of the art addresses the technical problem of controlling the level of induced thermal stress of vacuum-insulating glazing units when incorporated into multiple glazing that provides improved thermal performance as well as security, safety and/or acoustic benefits.

3. SUMMARY OF THE INVENTION

[0008] The present invention relates to a multiple glazing extending along a plane, P, defined by a longitudinal axis, X, and a vertical axis, Y comprising at least : a) a vacuum insulating glazing unit comprising a first glass pane having a thickness Z1, and having an inner pane face and an outer pane face and a second glass pane having a thickness Z2, and having an inner pane face and an outer pane face. The thicknesses are measured in the direction normal to the plane, P. The vacuum insulating glazing unit further comprises a set of discrete spacers positioned between the first and second glass panes, maintaining a distance between the first and the second glass panes; and a hermetically bonding seal sealing the distance between the first and second glass panes over a perimeter thereof. A internal volume, V, is defined by the first and second glass panes and the set of discrete spacers and closed by the hermetically bonding seal and wherein there is a vacuum having a pressure of less than 0.1 mbar. The inner pane faces face the internal volume, V; b) a third glass pane having an inner pane face and an outer pane face; and c) a peripheral spacer positioned between the outer pane face of the second glass pane and inner pane face of the third glass pane over a perimeter thereof, and that maintains a distance there between. The peripheral spacer, the outer pane face, and the inner pane face define an internal space, Sp.

[0009] The thickness of the first glass pane, Z1, is equal to the thickness of the second glass pane, Z2 (Z1 = Z2). The outer pane face of the first glass pane, GP1, is laminated via an interlayer polymer to a first panel, P1, comprising m glass sheet(s) each having a sheet thickness, Zfm; and/or the outer pane face of the second glass pane, GP2, is laminated via an interlayer polymer to a second panel, P2, comprising n glass sheet(s) each having a sheet thickness, Zsn. The thicknesses Zfm and Zsn are measured in the direction normal to the plane, P. The letter m is a positive integer greater than or equal to 0 (m ≥ 0). The letter n is a positive integer greater than or equal to 0 (n ≥ 0) and the sum of the m and n integers is greater than or equal to 1 (m + n ≥ 1).

[0010] The cubic root of the sum of the thickness(es) to the third power of the m glass sheet(s) of the first panel and/or of the n glass sheet(s) of the second panel, is equal to or lower than 126.7% of the sum of the thicknesses of the first glass pane and of the second glass pane,

[0011] In a preferred embodiment, the outer pane face of the first glass pane, GP1, is laminated via an interlayer polymer to a first panel, P1, comprising m glass sheet(s) each having a sheet thickness, Zfm; and the outer pane face (22) of the second glass pane, GP2, is laminated via an interlayer polymer to a second panel, P2, comprising n glass sheet(s) each having a sheet thickness, Zsn. In this instance, it is further preferred that the cubic root of the sum of the m glass sheet(s) of the first panel, is equal to the cubic root of the n glass sheet(s) of the second panel , [0012] The present invention further relates to a multiple glazing wherein cubic root of the sum of the thickness(es) to the third power of the m glass sheet(s) of the first panel and/or of the n glass sheet(s) of the second panel, is lower than or equal to 114.0% of the sum of the thicknesses of the first glass pane and of the second glass pane preferably lower than or equal to 101.4% of the sum of the thicknesses of the first glass pane and of the second glass pane more preferably lower than or equal to

88.7% of the sum of the thicknesses of the first glass pane and of the second glass pane even more preferably lower than or equal to 76.6% of the sum of the thicknesses of the first glass pane and of the second glass pane

[0013] The present invention further relates to a multiple glazing wherein cubic root of the sum of the thickness(es) to the third power of the m glass sheet(s) of the first panel and of the n glass sheet(s) of the second panel, is equal to or greater to 24% of the sum of the thicknesses of the first glass pane and of the second glass pane , preferably equal to or greater to 32% of the sum of the thicknesses of the first glass pane and of the second glass pane preferably is equal to or greater than 48% of the sum of the thicknesses of the first glass pane and of the second glass pane preferably is equal to or greater than 64% of the sum of the thicknesses of the first glass pane and of the second glass pane more preferably is equal to or greater than 80% of the sum of the thicknesses of the first glass pane and of the second glass pane

[0014] In a preferred embodiment, the cubic root of the sum of the thickness(es) to the third power of the m glass sheet(s) of the first panel and/or of the n glass sheet(s) of the second panel, is comprised between 64% and 101.4% of the sum of the thicknesses of the first glass pane and of the second glass pane preferably between 76% and 88.7% of the sum of the thicknesses of the first glass pane and of the second glass pane

[0015] Preferably, the positive integers are such that m + n ≤ 2, preferably equals 1. Preferably the positive integer n equals 0.

[0016] In a preferred embodiment of the present invention, the thickness of the m glass sheet of the first panel, Zfm, and/or of the n glass sheet of the second panel, Zsn; is/are equal to or greater than 1mm (Zfn and Zsm≥ 1 mm), preferably equal to or greater than 2 mm (Zfn and Zsm ≥ 2 mm); preferably is equal to or greater than 3 mm (Zfn and Zsm ≥ 3 mm); more preferably is equal to or greater than 4 mm (Zfn and Zsm ≥ 4 mm).

[0017] Within the multiple glazing of the present invention, the thickness of the first glass pane and/or of the second glass pane, is preferably comprised between 1mm and 10mm (1mm ≤ Z1,Z2 ≤ 10mm), preferably between 2mm and 8mm (2mm ≤ Z1, Z2 ≤ 8mm), more preferably between 3mm and 6mm (3mm ≤ Z1, Z2 ≤ 6mm). The thickness of the third glass pane, Z3, is preferably comprised between 1mm and 12mm (1mm ≤ Z3 ≤ 12mm), preferably between 3mm and 8mm (3mm ≤ Z3 ≤ 8mm), more preferably between 4mm and 6mm (4mm ≤ Z3 ≤ 6mm).

[0018] Preferably, the polymer interlayer comprises a material selected from the group consisting of ethylene vinyl acetate (EVA), Cyclo olefin polymers (COP), autoclave-free polyvinyl butyral (Autoclave- free PVB), polyurethane (PU), ionomers and combinations thereof, more preferably from ethylene vinyl acetate (EVA) and/or autoclave-free PVB.

[0019] In a preferred embodiment, the third glass pane of the multiple glazing is laminated to a glass sheet via an interlayer polymer. In such instance, preferably, the third glass pane has a thickness, Z3, comprised between 4mm and 8mm (4mm ≤ Z3 ≤ 8mm), preferably between 4mm and 6mm (4mm ≤ Z3 ≤ 6mm), and the glass sheet has a thickness Zs comprised between 4mm and 8mm (4mm ≤ Zs ≤ 8mm), preferably between 4mm and 6mm (4mm ≤ Zs ≤ 6mm), and more preferably the interlayer polymer is an acoustic PVB polymer interlayer. The thicknesses are measured in the direction normal to the plane, P.

[0020] In one preferred embodiment of the present invention, one glass pane of the multiple glazing is prestressed glass. In one embodiment, it is preferred that the first glass pane and/or the third glass pane is prestressed glass. In another embodiment, it is preferred that the second glass pane is prestressed glass.

[0021] Preferably, the first glass pane has a coefficient of linear thermal expansion, CTE1, and the second glass pane has a coefficient of linear thermal expansion, CTE2, and wherein the absolute difference between CTE1 and CTE2 is at most 1.2 10-6/°C ( | CTE1-CTE2 | ≤ 1.2 10-6/°C), preferably is at most 0.8 10-6/°C ( | CTE1-CTE2 | ≤ 0.8 10-6/°C), more preferably at most 0.4 10-6/°C ( | CTE1-CTE2 | ≤ 0.4 10-6/°C) , more preferably at most 0.2 10-6/°C ( | CTE1-CTE2 | ≤ 0.2 10-6/°C) even more preferably equals 0 ( | CTE1-CTE2 | = 0 /°C).

4. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] According to one embodiment of the present invention, Figure 1 shows a cross sectional view of a double glazing assembly comprising a single glass pane and a vacuum insulating glazing unit, wherein exterior glass pane of the vacuum insulating glazing unit has been laminated by one glass sheet.

[0023] According to one embodiment of the present invention, Figure 2 shows a cross sectional view of a double glazing assembly comprising a single glass pane and a vacuum insulating glazing unit, wherein both the single glass pane and the exterior glass pane of the vacuum insulating glazing unit have been laminated by one glass sheet respectively.

[0024] According to one embodiment of the present invention, Figure 3 shows a cross sectional view of a double glazing assembly comprising a single glass pane and a vacuum insulating glazing unit, wherein both glass panes of the vacuum insulating gazing unit have been laminated by one glass sheet respectively.

[0025] According to one embodiment of the present invention, Figure 4 shows a cross sectional view of a double glazing assembly, comprising a single glass pane and vacuum insulating glazing unit wherein the interior glass pane of the vacuum insulating glazing unit, has been laminated by two glass sheets.

5. DETAILED DESCRIPTION OF THE INVENTION

[0026] It is an object of the present invention to provide a multiple glazing that demonstrates a very high thermal insulation by the inclusion of a vacuum insulating glazing unit and that further provides the additional benefits of safety, security, anti-burglary and/or acoustics. [0027] Within this multiple glazing, the level of stress of the laminated vacuum insulating glazing unit should be controlled so that the thermal induced stress of the laminated VIG should at least not exceed its level of stress induced by a temperature difference between interior and exterior environments when not laminated. Another object of the present invention is even to reduce the level of thermal induced stress faced by the vacuum insulating glazing unit when incorporated into a multiple glazing, by laminating one or more additional glass sheet(s) to the outer pane face of the first and/or second glass pane(s) of the vacuum insulating glazing unit.

[0028] The vacuum insulating glazing unit will be hereinafter referred to as the "VIG". The present invention will be herein described further by reference to a double glazing assembly comprising a VIG and a single glass pane but it could be extended to any multiple glazing comprising one or more VIG(s) and one or more single glass pane(s). Another common multiple glazing is a triple glazing assembly comprising one or two VIG(s). All technical features and preferred technical features described herein further in relation to a double glazing assembly can be applied to triple and any other multiple glazing.

Thermal Induced stress calculation

[0029] Thermal induced stress is the stress induced on the glass panes of the VIG when said glass panes have significantly different temperatures. The thermal induced stress is the combination of shear and bending stresses across the thickness of the VIG. The thermal induced stress profile across a VIG is known in the art as per Timoshenko in the article "Timoshenko, S., Analysis of Bi-metal Thermostats. JOSA, 1925. 11(3): p. 233-255" used to calculate stresses in bimetallic strips and, which can be easily extended to vacuum insulating glazing. The thermal induced stress profile as per Timoshenko can easily be extended further to consider laminated VIG: the assumption is made that the shear transfer coefficient of the polymer interlayer equals to 0. This assumption, widely accepted in the art, is based on the slow variations of temperature observed when a VIG is exposed to the daily temperature differences of its environment. Therefore, only the bending stress is considered within the additional glass sheet(s) laminated to the glass pane of the VIG.

[0030] The above described analytical solution allows to calculate the thermal induced stress for all VIG configurations. The thermal induced stress for a non-laminated VIG construction having a first glass pane of a given thickness Z1 and a second glass pane of a given thickness Z2, is calculated and its maximal tensile stress on its external surface will be considered as the reference thermal induced stress value that should not be exceeded by the corresponding laminated VIG. Similarly, for a given VIG construction, the above described analytical solution allows to calculate thermal induced stresses and the value of the maximal tensile stress on the VIG external surface; for different lamination configurations of increasing thickness, i.e. wherein the VIG construction is laminated to one or more additional glass sheet(s) of increasing thicknesses.

Thermal induced stress of the VIG within the multiple glazing

[0031] In use, glazing are typically used to close the partition separating an interior space from an exterior space. The temperature of the interior space is typically from 20 to 25°C whereas the temperature of the exterior space can extend from -20°C in the winter to +35°C in the summer. Therefore, the temperature difference between the interior space and the exterior space can typically reach more than 40°C in severe conditions.

[0032] In the present invention, the VIG within the multiple glazing is separating a space A, characterized by a temperature, TempA, from the internal space of the double gazing unit characterized by an internal temperature, Tempint. If the VIG is positioned so that its first glass pane, GP1, is facing the first space, A, the temperature of said first glass pane (T1) will adjust with the temperature of the first space (TempA). Similarly, the third glass pane, GP3, is separating a space B, characterized by a temperature, TempB from the internal space. The temperature of said third glass pane, (T3) will adjust with the temperature of the second space (TempB). The temperature (T2) of the second glass pane, GP2, facing the internal space will adjust with the temperature of the internal space (Tempint).

[0033] Typically for double glazing, the temperature of the internal space (Tempint) was expected to reach a mean temperature between TempA and TempB, slightly affected by solar radiation. It has been surprisingly found that in a double glazing wherein at least one of the single glass pane has been replaced by a VIG, the temperature of the internal space (Tempint) is strongly affected by solar radiation and can reach a much higher temperature than TempA and TempB.

[0034] Thermal induced stress occurs as soon as there is a temperature difference between the first glass pane (GP1 and T1) and the second glass pane (GP2 and T2) and increases with increasing difference between T1 and T2. The temperature difference (ΔT) is the difference between the mean temperature T1 calculated for the first glass pane, GP1, and the mean temperature T2 calculated for the second glass pane, GP2. The mean temperature of a glass pane is calculated from numerical simulations known to the skilled people. Thermal induced stress becomes problematic - up to potential breaking of the VIG, when the absolute value of the temperature difference ( | ΔT | ) between the glass panes, reaches 20°C and becomes critical when such absolute value of the temperature difference reaches 30°C and even more when it reaches 40°C in severe conditions. [0035] It has been further found that when the VIG is included into a multiple glazing, such absolute value of the temperature difference between the glass panes ( | ΔT | ) can reach even higher values than the corresponding temperature difference typically reached in a stand-alone VIG.

[0036] The table below shows data (from the location of Munich Airport) wherein the absolute value of the temperature difference ( | ΔT | ) in the summer is much higher for the VIG within the multiple glazing than for the stand-alone VIG.

[0037] Data temperature have been measured for a double glazing configuration comprising a VIG a single glass pane facing the exterior of the building. The single glass pane is separated from the VIG by a peripheral spacer of 15mm and the internal space is filled with argon. The single glass pane has a solar control coating, on its surface facing the internal space of the double glazing. The VIG comprises a first glass pane, GP,1 and a second glass pane, GP2, both having a thickness of 4mm each. The second glass pane faces the internal space of the double glazing. The first glass pane has a low-emissivity coating on its surface facing the internal volume of the VIG.

[0038] The outside temperature can reach 32°C in summer and -23°C in winter for a temperature of 20°C inside the building. The absolute value of the temperature difference ( | ΔT | ) would therefore amount to about 11°C in summer and about 39°C in winter for a stand-alone VIG. When the VIG is configurated as a double glazing, the temperature in the internal space (Tempint) can reach 68°C in summer and -10°C in winter. Therefore, the absolute value of the temperature difference ( | ΔT | ) faced by the VIG within the multiple glazing, would amount to about 31°C in summer and 27°C in winter. It can be seen from these data, that for a VIG within a multiple glazing, the absolute value of the temperature difference ( | ΔT| ) in summer is similar to the absolute value of the temperature difference ( | ΔT | ) in winter. This is in contrast, for a VIG stand-alone for which the absolute value of the temperature difference ( | ΔT | ) in winter is higher than the absolute value of the temperature difference ( | ΔT | ) in summer. Therefore, the skilled person in the art needs not only to consider the absolute value of the temperature difference ( | ΔT | ) in winter but also, the absolute value of the temperature difference ( | ΔT| ) in summer, to control the thermal induced stresses in the VIG and avoid breakage.

[0039] The table below illustrates the temperature difference (ΔT) being the difference between the mean temperature T1 calculated for the first glass pane, GP1, and the mean temperature T2 calculated for the second glass pane, GP2.

[0040] In such instances where the absolute value of the temperature difference ( | ΔT | ) in winter and summer are close to one another and hence both summer and winter conditions must be considered, it has been surprisingly found that the VIG when incorporated in a multiple glazing, should be configured so that the thickness of the first and the second glass panes are the same and that lamination of the VIG glass pane(s) increases the resistance to thermal induced stress. It has been further found that lamination of the VIG glass pane(s) increases the resistance to thermal induced stress up to a certain point and that further increasing the thickness of the glass pane(s) of the VIG by lamination, does surprisingly then deteriorate the resistance to thermal induced stress.

[0041] As demonstrated above, when incorporated into a multiple glazing, the VIG must be carefully dimensioned to resist to the thermal induced stress specific to its environment of use and to the multiple glazing configuration. Therefore, the object of the present invention is to bring additional performances to the glazing such as safety, security, anti-burglary and/or acoustics by lamination of one or more of the glass panes of the VIG while maintaining and even reducing the level of thermal induced stress, when incorporated into a multiple glazing. It has been surprisingly found that by carefully designing the thickness(es) of the additional glass sheet(s) that will be laminated to the one or both of the glass pane(s) of the VIG, the benefit of safety, security, anti-burglary and/or acoustics can be added without impairing and even improving its mechanical resistance to thermal induced stress. It has further been found that in such configuration circumstances, the benefit of laminating one or both glass pane(s) of the VIG does work even better when the glass panes of the VIGs have the same thickness.

[0042] Such additional glass sheet that will be laminated to the VIG will be hereinafter referred to as the "panel". This panel will be laminated to the outer pane face of the first and/or second glass pane(s) of the VIG via an interlayer polymer to form a laminated vacuum insulating glazing unit hereinafter referred to as "laminated VIG". The outer pane face of the first glass pane is facing the exterior of the glazing and the outer pane face of the second glass pane is facing the internal space of the multiple glazing. The interlayer polymer is positioned between the outer pane face of the first and/or the second glass panes of the VIG and the first and/or second panel repectively, to form a laminated assembly.

The present invention

[0043] Hence, as illustrated in Figures 1 to 4, the present invention relates to a multiple glazing (10) extending along a plane, P, defined by a longitudinal axis, X, and a vertical axis, Y comprising at least a vacuum insulating glazing unit. The VIG comprises a first glass pane, GP1, having a thickness Z1, and having an inner pane face (11) and an outer pane face (12) and a second glass pane, GP2, having a thickness, Z2, and having an inner pane face (21) and an outer pane face (22). The thicknesses are measured in the direction normal to the plane, P. The VIG further comprises a set of discrete spacers (3) positioned between the first and the second glass panes, maintaining a distance between the first and the second glass panes; and a hermetically bonding seal (4) sealing the distance between the first and that second glass panes over the perimeter thereof. An internal volume, V, is defined by the first and second glass panes and the set of discrete spacers and closed by the hermetically bonding seal; wherein there is vacuum having a pressure of less than 0.1 mbar. The inner pane faces of the VIG face the internal volume, V. The thickness of the first glass pane, Z1, is equal to the thickness of the second glass pane, Z2 (Z1 = Z2).

[0044] Within the VIG, the outer pane face (12) of the first glass pane, GP1, is laminated via an interlayer polymer to a first panel, P1, comprising m glass sheet(s) - each glass sheet having a sheet thickness, Zfm; and/or the outer pane face (22) of the second glass pane, GP2, is laminated via an interlayer polymer to a second panel, P2, comprising n glass sheet(s) - each glass sheet having a sheet thickness, Zsn. The thicknesses Zfm and Zsn are measured in the direction normal to the plane, P. The letter m is a positive integer greater than or equal to 0 (m ≥ 0), the letter n is a positive integer greater than or equal to 0 (n ≥ 0) and the sum of the m and n integers is greater than or equal to 1 (m + n ≥ 1). When the integer m or n equals 0 (m=0 or n= 0), then the corresponding sheet thickness equals 0 (Zs0 = 0 or Zf0 = 0). The first panel can be a single glass sheet (m=1) or can comprise m glass sheets (m>1) laminated together via an m-1 interlayer polymer. Similarly, the second panel can be a single glass sheet (n=1) or can comprise n glass sheets (n >1) laminated together via an n-1 interlayer polymer.

[0045] The present invention is based on the surprising finding that there is a critical correlation between the thickness of the glass panes of the VIG and of the glass sheet(s) of the panel to maintain and even improve the resistance of the VIG to thermal induced stress, also in the more stringent thermal profile of the multiple glazing. It has been surprisingly found that laminating the first and/or second glass pane of the VIG with first and/or second panel(s) of specific thickness and designing the VIG such that the first and the second glass panes of the VIG have the same thickness, allows to maintain and even improve the resistance to thermal induced stress of such VIG when incorporated into a multiple glazing. Therefore, it has been found that the thickness of the glass sheet(s) within the first and/or that second panel should but such that the cubic root of the sum of the thickness(es) to the third power of the m glass sheet(s) of the first panel, P1 and of the n glass sheet(s) of the second panel, P2, is equal to or lower than 126.7% of the sum of the thicknesses of the first glass pane and of the second glass pane,

[0046] The multiple glazing of the present invention further comprises a third glass pane, GP3, having an inner pane face (31) and an outer pane face (32); and a peripheral spacer (6) positioned between the outer pane face (22) of the second glass pane, GP2, of the VIG and the inner pane face (31) of the third glass pane, GP3, over a perimeter thereof, and maintaining a distance there between. The peripheral spacer (6), the outer pane face (22), and the inner pane face (31) define an internal space, Sp.

[0047] In a preferred embodiment of the present invention, the outer pane face (12) of the first glass pane, GP1, is laminated via an interlayer polymer to a first panel, P1, comprising m glass sheet(s) - each glass sheet having a thickness, Zfm and the outer pane face (22) of the second glass pane, GP2, is laminated via an interlayer polymer to a second panel, P2, comprising n glass sheet(s) - each glass sheet having a thickness, Zsm. In such instance, it is then further preferred that the cubic root of the sum of the m glass sheet(s) to the third power of the first panel, P1, is equal to the cubic root of the n glass sheet(s) to the third power of the second panel, P2,

[0048] In a preferred embodiment of the present invention, the cubic root of the sum of the thickness(es) to the third power of the m glass sheet(s) of the first panel, P1 and of the n glass sheet(s) of the second panel, P2, is lower than or equal to 114.0% of the sum of the thicknesses of the first glass pane and of the second glass pane preferably lower than or equal to 101.4% of the sum of the thicknesses of the first glass pane and of the second glass pane more preferably lower than or equal to 88.7% of the sum of the thicknesses of the first glass pane and of the second glass pane even more preferably lower than or equal to 76.6% of the sum of the thicknesses of the first glass pane and of the second glass pane

[0049] In a preferred embodiment of the present invention, the cubic root of the sum of the thickness(es) to the third power of the m glass sheet(s) of the first panel and of the n glass sheet(s) of the second panel, is equal to or greater than 24% of the sum of the thicknesses of the first glass pane and of the second glass pane preferably equal to or greater than 32% of the sum of the thicknesses of the first glass pane and of the second glass pane preferably equal to or greater than 48% of the sum of the thicknesses of the first glass pane and of the second glass pane x (Z1 + Z2)), preferably is equal to or greater than 64% of the sum of the thicknesses of the first glass pane and of the second glass pane more preferably equal to or greater than 80% of the sum of the thicknesses of the first glass pane and of the second glass pane

[0050] In a further preferred embodiment, the thickness(es) of the glass sheets to be laminated to the first and/or the second glass pane of the VIG are such that the cubic root of the sum of the thickness(es) to the third power of the m glass sheet(s) of the first panel, P1, and of the n glass sheet(s) of the second panel, P2, is(are) comprised between 64% and 101.4% of the sum of the thicknesses of the first glass pane and of the second glass pane more preferably between 76.6% and 88.7%

It is further preferred that the sheet thickness(es), Zfm and/or Zsn, is(are) equal to or greater than 1mm (Zfm and/or Zsn ≥ 1mm), preferably equal to or greater than 2mm (Zfm and/or Zsn ≥ 2mm), preferably equal to or greater than 3mm (Zfm and/or Zsn ≥ 3mm); preferably equal to or greater than 4mm (Zfm and/or Zsn ≥ 4mm). In a preferred embodiment, the sheet thickness(es), Zfm and/or Zsn, are comprised between 1mm and 8mm (1mm ≤ Zfm and/or Zsn ≤ 8mm), preferably between 1mm and 6mm (1mm ≤ Zfm and/or Zsn ≤ 6mm), more preferably 2mm and 6mm (2mm ≤ Zfm and/or Zsn ≤ 4mm), preferably equals 4mm (Zfm and/or Zsn = 4mm). When two or more glass sheets are laminated to the outer pane face of the first and/or the second glass pane of the VIG, the thickness of each glass sheet can be identical or different. The sheet thicknesses are measured in the direction normal to the plane, P.

[0051] In one preferred embodiment of the present invention, the sum of the m and n integers is equal to or lower than 2 (m + n ≤ 2), preferably is equal to 1 (m + n = 1). More preferably, the integer m equals 1 (m=1) and the integer n equals 0 (n=0) as shown in Figure 1. Figure 1 illustrates a multiple glazing wherein only the first glass pane of the VIG is laminated to a first panel comprising one glass sheet. The outer pane face (12) of the first glass pane, GP1, is laminated to a first panel, P1, comprising one glass sheet having a thickness, Zf ₁ , by one polymer interlayer (7) to form a first laminated assembly. The thickness of the single glass sheet, Zf ₁ is measured in the direction normal to the plane, P.

[0052] In another preferred embodiment of the present invention, the sum of the m and n integers is equal to or lower than 2 (m + n ≤ 2), preferably is equal to 2 (m + n = 2). More preferably, the integer m equals 1 (m=1) and the integer n equals 1 (n=1) as shown in Figure 2. Figure 3 illustrates a multiple glazing wherein the first glass pane of the VIG is laminated to a first panel comprising one glass sheet and the second glass pane is laminated to a second panel comprising one glass sheet. Hence, the outer pane face (12) of the first glass pane, GP1, is laminated to a first panel, P1, comprising one glass sheet having a thickness, Zf ₁ , by one polymer interlayer (7) to form a first laminated assembly. The outer pane face (22) of the second glass pane, GP2, is laminated to a second panel, P2, comprising one glass sheet having a thickness, Zs ₁ , by one polymer interlayer (7) to form a second laminated assembly. The thicknesses of the first and of the second glass sheets, Zf ₁ and Zs ₂ , are measured in the direction normal to the plane, P.

[0053] In the embodiment of the present invention wherein the VIG of the multiple glazing of the present invention, is laminated to a first panel and a second panel, it is further preferred that the sum of the thicknesses of the m glass sheet(s) within the first panel equals the sum of the thicknesses of the n glass sheet(s) within the second panel. In this embodiment, the cubic root of the sum of the m glass sheet(s) of the first panel, is equal to the cubic root of the n glass sheet(s) of the second panel, It has been found that such lamination configuration brings additional resistance to the thermal induced stress especially when the thickness of the glass sheets within each first and second panels are equal, since it avoids bringing asymmetry to the VIG. [0054] In another embodiment of the present invention as illustrated in Figure 4, the second glass pane, GP2, is laminated to a second panel, P2 via an interlayer polymer. The second panel, P2, comprises two glass sheets (n = 2) having respectively a thickness Zs ₁ and Zs ₂ , and one (n-1) interlayer polymer (7). When the second glass pane of the VIG is laminated to a second panel via an interlayer polymer, it can be that the second panel is of smaller dimension. The panel, P2, and the second glass pane, GP2, comprise peripheral edges. The peripheral edges of the second Panel are recessed from the peripheral edges of the second glass pane.

The interlayer polymer

[0055] The interlayer polymer comprises typically a material selected from the group consisting of ethylene vinyl acetate (EVA), polyisobutylene (PIB), polyvinyl butyral (PVB), autoclave-free polyvinyl butyral (Autoclave-free PVB), polyurethane (PU), polyvinyl chlorides (PVC), polyesters, copolyesters, polyacetals, cyclo olefin polymers (COP), ionomers and/or an ultraviolet activated adhesive, and others known in the art of manufacturing glass laminates. Reinforced acoustic insulation can be provided with a polymer interlayer with specific acoustic performance, such as specific PVBs (Saflex® acoustic PVB interlayer from Eastman or Trosifol® acoustic PVB interlayer from Kuraray). Preferably, the polymer interlayer is selected from the group consisting of ethylene vinyl acetate (EVA), Cyclo olefin polymers (COP), autoclave-free polyvinyl butyral (Autoclave-free PVB), polyurethane (PU), ionomers like SentryGlas™ and combinations thereof, more preferably from EVA and/or autoclave- free PVB.

[0056] The thickness of the interlayer polymer is not particularly limited and may be for example, from 0.25 mm to 5 mm, preferably from 0.3 mm to 5 mm, preferably 0.3 to 4mm, more preferably from 0.3mm to 2.5mm. To achieve the desired thickness, one or more films of commercially available interlayer polymer can be used. Examples thereof are the commercially available polyvinyl butyral (PVB) films of 0.38 mm.

[0057] In a preferred embodiment, the third glass pane, GP3, of the multiple glazing can also be laminated to at least a glass sheet by a polymer interlayer to form a laminated glass pane. As illustrated in Figure 2 , the first glass pane is laminated to a first panel comprising a single glass sheet as illustrated in Figure 1 and outer pane face (32) of the third glass pane, GP3, is laminated to one glass sheet, Gs, via an interlayer polymer (7). The glass sheet has a thickness Zs, measured in the direction normal to the plane, P.

[0058] In a preferred embodiment, the third glass pane has a thickness, Z3, measured in the direction normal to the plane, P; comprised between 4mm and 8mm (4mm ≤ Z3 ≤ 8mm), preferably between 4mm and 6mm (4mm ≤ Z3 ≤ 6mm), and the third glass pane is laminated to a glass sheet having a thickness Zs comprised between 4mm and 8mm (4mm ≤ Zs ≤ 8mm), preferably between 4mm and 6mm (4mm ≤ Zs ≤ 6mm), preferably by an acoustic PVB polymer interlayer. It is further preferred that the thickness of the third glass pane and the thickness of the glass sheet(s) are different (Z3 ≠ Zs).

[0059] Typically, the glass panes and glass sheet(s) are annealed glass panes and annealed glass sheet(s). However, to provide a multiple glazing with higher mechanical performances and/or to improve further the safety, it can be contemplated to use prestressed glass for one or more glass pane(s), preferably for the first glass pane and/or the third glass pane. By prestressed glass, it is meant herein a heat strengthened glass, a thermally toughened safety glass, or a chemically strengthened glass. In a preferred embodiment, the multiple glazing comprise a third glass pane, GP3, made of prestressed glass, and a VIG wherein the second glass pane, GP2, is laminated to a second panel comprising one sheet and the first glass pane, GP1, is prestressed. In another preferred embodiment, the second glass pane is a prestressed glass.

[0060] Heat strengthened glass and thermally toughened safety glass are heat treated using a method of controlled heating and cooling which places the glass surface(s) in compression and the other core under tension. The heat treatment method delivers a glass with a bending strength greater than annealed glass but less than thermally toughened safety glass. The thermally toughened safety glass when impacted, breaks into small granular particles instead of splintering into jagged shards. The granular particles are less likely to injure occupants or damage objects. The chemical strengthening of a glass article is a heat induced ion-exchange, involving replacement of smaller alkali sodium ions in the surface layer of glass by larger ions, for example alkali potassium ions. Increased surface compression stress occurs in the glass as the larger ions "wedge" into the small sites formerly occupied by the sodium ions. Such a chemical treatment is generally carried out by immerging the glass in an ion-exchange molten bath containing one or more molten salt(s) of the larger ions, with a precise control of temperature and time. Aluminosilicate-type glass compositions, such as for example those from the product range DragonTrail® from Asahi Glass Co. or those from the product range Gorilla® from Corning Inc., are known to be very efficient for chemical tempering.

VACUUM INSULATING GLAZING

[0061] VIGs typically comprise a first glass pane and a second glass pane that are associated together by means of a set of discrete spacers that hold said panes a certain distance apart, typically in the range of between 50 μm and 1000 μm, preferably between 50 μm and 500 μm and more preferably between 50μm and 150μm, and between said glass panes, an internal space comprising at least one first cavity, in which cavity there is a vacuum of absolute pressure of less than 0.1 mbar. Said space being closed by a peripheral hermetically bonding seal placed on the periphery of the glass panes around said internal space. In general, in order to achieve a high-performance thermal insulation (Thermal transmittance, Ug, being Ug<1.2 W/m ² K, preferably Ug<0.8 W/m ² K), the pressure inside the glazing unit is typically O.lmbar or less and generally at least one of the two glass panes is covered with a low-emissivity coating.

[0062] The present invention relates to a multiple glazing (10) comprising at least one vacuum insulating glazing unit (20), a third glass pane, GP3, and a peripheral spacer (6). In one embodiment of the present invention, the multiple glazing can comprise only VIG units so that above described single glass pane, GP3, is incorporated within a vacuum insulating unit comprising the single glass pane, GP3, and an additional glass pane, GP4, forming together a second VIG unit similar to the VIG described above. All technical features and preferred technical features described herein above and further in relating to the double glazing or multiple glazing comprising a single glass pane, can be applied respectively to multiple glazing configuration. Therefore, in this embodiment, the third glass pane, GP3, is further associated to a fourth glass, GP4, by a set of discrete spacers (3) positioned between the third and the fourth glass panes, maintaining a distance between them; a hermetically bonding seal (4) sealing the distance between them over a perimeter thereof; creating an internal volume, V, wherein there is a vacuum having a pressure of less than 0.1 mbar.

[0063] The thickness of the first and/or second glass panes, Z1, Z2, of the VIG, and/or of the third glass pane, Z3, of the multiple glazing are typically equal to or greater than 2mm (Z1, Z2, Z3 ≥ 2mm), preferably are equal to or greater to 3 mm, (Z1, Z2, Z3 ≥ 3mm), more preferably equal to or greater to 4 mm, (Z1, Z2, Z3 ≥ 4 mm) more preferably equal to or greater to 6 mm, (Z1, Z2, Z3 ≥ 6mm). Typically, the thickness of the first and/or second glass panes, and/or of the third glass pane, Z3, will be not more than 12mm (Z1, Z2, Z3 ≤ 12mm), preferably not more than 10mm (Z1, Z2, Z3 ≤ 10mm), more preferably not more than 8mm (Z1, Z2, Z3 ≤ 8mm). The thicknesses are measured in the direction normal to the plane, P. In a preferred embodiment of the present invention, the thickness of the first and second glass pane, Z1 and/or Z2, is comprised between 1mm and 10mm (1mm ≤ Z1,Z2 ≤ 10mm), preferably between 2mm and 8mm (2mm ≤ Z1, Z2 ≤ 8mm), more preferably between 3mm and 6mm (3mm ≤ Z1, Z2 ≤ 6mm). In a preferred embodiment, the thickness of the third glass pane, Z3, is comprised between 1mm and 12mm (1mm ≤ Z3 ≤ 12mm), preferably between 3mm and 10mm (3mm ≤ Z3 ≤ 10mm), more preferably between 4mm and 8mm (4mm ≤ Z3 ≤ 8mm).

[0064] Preferably, the thickness of the m glass sheet(s) of the first panel, Zfm, and/or of the n glass sheet(s) of the second panel, Zsn; is/are equal to or greater than 1mm (Zfn and Zsm≥ 1 mm), preferably equal to or greater than 2 mm (Zfn and Zsm ≥ 2 mm); preferably is equal to or greater than 3 mm (Zfn and Zsm ≥ 3 mm); more preferably is equal to or greater than 4 mm (Zfn and Zsm ≥ 4 mm).

[0065] In a preferred embodiment of the present invention, the multiple glazing has a length, L, measured along the vertical axis, Y; equal to or greater than 500 mm, (L ≥ 500 mm), equal to or greater than 800 mm (L ≥ 800 mm), more preferably equal to or greater than 1200 mm, (L ≥ 1200 mm). In a preferred embodiment of the present invention, the multiple glazing has a width, W, measured along the longitudinal axis, X; equal to or greater than 300 mm, (W ≥ 300 mm), preferably equal to or greater than 400mm, (W ≥ 400 mm) more preferably equal to or greater than 500mm, (W ≥ 500 mm), more preferably equal to or greater than 750 mm, (W ≥ 750 mm); more preferably equal to or greater than 1000 mm, (W ≥ 1000 mm); even more preferably equal to or greater than 1000 mm, (W ≥ 1000 mm).

Spacers

[0066] The discrete spacers (also referred to as "pillars") are positioned between the first and the second glass panes, maintaining a distance there between them and forming an array having a pitch, λ, comprised between 10 mm and 100 mm (10 mm ≤ λ ≤ 100 mm). By pitch, it is meant the interval between the discrete spacers. In a preferred embodiment, the pitch is comprised between 15 mm and 80 mm (15 mm ≤ λ ≤ 80 mm), preferably between 15 mm and 50 mm (15 mm ≤ λ ≤ 50 mm) preferably between 15 mm and 40 mm (25 mm ≤ λ ≤ 40 mm), more preferably between 15 mm and 25 mm (15 mm ≤ λ < 25 mm), even more preferably is about 20 mm. The array within the present invention is typically a regular array based on an equilateral triangular, square or hexagonal scheme, preferably based on a square scheme. The discrete spacers can have different shapes, such as cylindrical, spherical, filiform, hourglass, C-shaped, cruciform, prismatic shape... It is preferred to use small pillars, i.e. pillars having in general a contact surface with the glass pane, defined by its external circumference, equal to or lower than 5 mm ² , preferably equal to or lower than 3 mm ² , more preferably equal to or lower than 1 mm ² . These values may offer a good mechanical resistance whilst being aesthetically discrete.

[0067] Typical discrete spacers are made of a material with durable resistance to the pressure and high-temperature faced during the production process of the VIG and hardly emitting any gas after the glazing is manufactured. Such a material is preferably a hard material such as metal material, quartz glass or a ceramic material, in particular a metal material such as iron, tungsten, nickel, chrome, titanium, molybdenum, carbon steel, chrome steel, nickel steel, stainless steel, nickel-chromium steel, manganese steel, chromium-manganese steel, chromium-molybdenum steel, silicon steel, nichrome, duralumin or the like. Another such material can be a ceramic material such as corundum, alumina, mullite, magnesia, yttria, aluminum nitride, silicon nitride or the like. However, if such material provides higher mechanical resistance, they provide rather poor performance in thermal conductivity (high thermal conductivity). Therefore, preferred discrete spacers for the VIG element of the multiple glazing of the present invention are made of material of lower conductivity such as resins, preferably made of polyimide resin. In this case, it is possible to minimize the thermal conductivity of the spacer and heat is hardly transferred via the discrete spacers in contact with the first and the second glass panes.

The hermetically Bonding Seal

[0068] The internal volume of the VIG is closed with a hermetically bonding seal placed on the periphery of the glass panes around said internal space. The hermetically bonding seal is impermeable to air or any other gas present in the atmosphere. Various hermetically bonding seal technologies exist. A first type of seal (the most widespread) is a seal based on a solder glass for which the melting point is lower than that of the glass panes of the glazing unit. Typically lower than 500°C, preferably lower than 450°C, more preferably lower than 400°C. Examples are low melting point glass frits such as bismuth based glass frits, lead based glass frits, vanadium based glass frits and mixtures thereof. A second type of seal comprises a metal seal, for example a metal strip of a small thickness (<500 μm) soldered to the periphery of the glazing unit by means of a tie underlayer covered at least partially with a layer of a solderable material such as a soft tin-alloy solder.

Internal volume

[0069] A vacuum of absolute pressure less than 0.1 mbar, preferably less than 0.01mbar is created, within the internal volume, V, defined by the first and second glass panes and the set of discrete spacers and closed by the hermetically bonding seal. A getter can be used to maintain for the duration a given vacuum level in a vacuum-insulating glazing unit. Generally, such a getter consists of alloys of zirconium, vanadium, iron, cobalt, aluminum, etc., and is deposited in the form of a thin layer (a few microns in thickness) or in the form of a tablet placed between the glass panes.

PANES and SHEETS

[0070] The VIG glass panes, GP1 and GP2 and the third glass pane, GP3, can be chosen among float clear, extra-clear or colored glass. Typically, the glass panes are soda-lime-silica glass, aluminosilicate glass or borosilicate glass; preferably soda-lime-silica glass. Textured, structured, printed glass are suitable. The glass panes can optionally be edge-ground for safety.

[0071] Preferably, the composition of the glass pane comprises the following components in weight percentage, expressed with respect to the total weight of glass (Comp. A). More preferably, the glass composition (Comp. B) is a soda-lime-silicate-type glass with a base glass matrix of the composition comprising the following components in weight percentage, expressed with respect to the total weight of glass. [0072] Other preferred glass comprises the following components in weight percentage, expressed with respect to the total weight of glass:

[0073] In a preferred embodiment, within the VIG, the first glass pane has a coefficient of thermal expansion, CET1, and the second glass pane has a coefficient of thermal expansion, CET2, whereby the absolute difference between CET1 and CET2 is equal to or at most 0.40 10-6/°C ( | CET1-CET2 | ≤0.40

10-6/°C); preferably is at most 0.30 10-6/°C ( | CET1-CET2 | ≤0.30 10-6/°C), more preferably equal to or at most 0.20 10-6/°C ( | CET1-CET2 | ≤0.20 10-6/°C). Ideally, the first and second glass panes have the same coefficient of thermal expansion ( | CTE1-CTE2 | = 0 /°C). The "coefficient of thermal expansion" (CTE) is a measure of how the size of an object changes with a change in temperature. Specifically, it measures the fractional change in volume of the glass pane per degree change in temperature at a constant pressure. [0074] In some embodiments of the present invention, functional coatings such as low emissivity coatings, solar control coatings (heat ray reflection coatings), anti-reflective coatings, anti-fog coatings, preferably a heat ray reflection coating or a low emissivity coating, can be provided on at least one of the glass panes of the multiple glazing unit. Preferably, the inner pane face of the first and/or second glass pane(s); the inner pane face and/or outer pane face of the third glass pane; and/or the outer sheet face of the glass sheet - if one of the glass panes of the multiple glazing has been further laminated to a glass sheet; is provided with at least a heat ray reflection coating or a low-emissivity coating. As illustrated in Figures I to 4, the inner pane face (11) of the first glass pane, GP1, can typically be coated with a low-emissivity coating (5).

[0075] In one embodiment, the outer pane face of the first glass pane (12) can be provided with at least one spall shield polymer film, preferably with a polyester spall shield film.

THE MULTIPLE GLAZING

[0076] Within the multiple glazing of the present invention, the peripheral spacer maintains a certain distance between the third glass pane and the second glass pane of the VIG . The peripheral spacer extends along the edges of the glazing and is positioned between the outer pane face of the second glass pane GP2 and the inner pane face of the third glass pane GP3 over a perimeter thereof, and maintaining a distance there between, wherein the peripheral spacer and said outer pane faces define an internal space, Sp.

[0077] Typically said spacer comprises a desiccant and has typically a thickness comprised between 4 mm to 32 mm, preferably 4 to 22 mm preferably 4 to 16 mm, more preferably 6 to 12 mm. In general, said second internal volume is filled with air and/or an inert gas. The nature of gas and the distance between GP2 an GP3 are selected to provide appropriate reduction of heat transfer and/or sound transmission. The internal space Sp is filled with air and/or inert gas selected from dry air, argon, xenon, krypton, or mixtures thereof, preferably from argon or a mixture of air and argon.

[0078] In its role of maintaining an internal space Sp, the peripheral spacer must of course provide proper tightness properties. It is critical for a peripheral spacer to prevent the release of inert gas from the internal space Sp and/or also to prevent the entry of water vapor. The peripheral spacer is typically an object of elongated shape and constant cross section. The peripheral spacer may be a solid or hollow element. [0079] Examples of peripheral spacer include metal spacer, ceramic spacer, glass spacer, polymeric spacer, and combinations or composites thereof. Examples of polymeric peripheral spacer include polyisobutylene-butyl mixture, silicone rubber foam, polypropylene, PVC, styrene acrylo nitrile or biopolymers, and mixtures or combinations of these. Further examples of polymeric peripheral spacer include transparent rigid materials such as polymethylmethacrylate (PMMA), polycarbonate, polystyrene, polyamide and/or polyester, which may provide transparency along the edges. Metal, ceramic or glass peripheral spacers are also suitable materials. Examples of metal include galvanized steel, stainless steel, aluminum alloy. Examples of composite peripheral spacer include polypropylene/stainless steel.

[0080] In a preferred embodiment of the present invention, the peripheral spacer within the multiple glazing is a warm edge peripheral spacer that has a better thermal performance than standard aluminum spacer bar. A thermally improved spacer has a thermal conductance value of ≤ 0.007 W/K calculated according to EN10077-1 annex E.

[0081] The peripheral spacer may have adhesive properties, such that it adheres directly to the glass pane faces in contact with it. For instance, polyisobutylene-butyl mixture (also known as thermoplastic spacer or TPS), in extruded form, have intrinsic tightness and adhesion properties. They offer the advantage of allowing good adhesion to the glass panes, and to compensate for irregularities in the flatness of these panes, thus ensuring a good seal. They also offer the advantage to adapt to all possible shapes.

[0082] In other instances where the peripheral spacer does not have adhesive properties such as silicone rubber foam, a first peripheral seal is required between the third glass pane and the peripheral spacer and between the second glass pane and the peripheral spacer. The adhesive provides the tightness and contributes to the mechanical strength of the construction. Examples of first peripheral seal materials include polyisobutylene, acrylic resin, epoxy resin, polyurethane resin, and mixtures or combinations thereof. Preferred first peripheral seal materials are polyisobutylene and/or acrylic resin.

[0083] The peripheral spacer may typically be provided with a desiccative material. When the paripheral spacer is a hollow frame, the desiccative material will at least partially fill the hollow space. Examples of desiccative materials capable of filling the hollow space are silica gels, zeolite and other molecular sieves. When the peripheral spacer is a solid polymeric frame, the desiccative material may be incorporated into the polymer matrix. An example of such a desiccative polymer is a polymer comprising an integrated molecular sieve. [0084] If the first peripheral seal is not enough to provide the required gas tightness and/or mechanical strength, a second peripheral seal may be present between the single glass pane and the VIG and cover the peripheral spacer and first peripheral seal towards the exterior. This second peripheral seal may serve for the air tightness of the internal space and for mechanical support of the glazing. The second peripheral seal typically has a very good mechanical strength, in addition to adhesion of glass and possibly water vapor and gas tightness. Examples of second peripheral seal materials include polyisobutylene, silicone, polysulfide, polyurethane or mixtures or combinations thereof. Preferred second peripheral seal materials are silicone, polysulfide and/or polyuretane.

[0085] The multiple glazing of the present invention is typically used to close an opening within a partition in buildings, in transport such as cars, train, boats,... and in appliances such as fridges, cold cabinets,.... The partition typically separates the exterior environment from an interior space such as the interior of a building or a car. In the present invention, the multiple glazing can be used such that the single glass pane, GP3, faces the exterior environment or the interior space, preferable faces the exterior environment.

[0086] The person skilled in the art realizes that the present invention is by no means limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. It is further noted that the invention relates to all possible combinations of features, and preferred features, described herein and recited in the claims. It is well understood by persons skilled in the art that, as used herein the terms "a", "an" or "the" means at least "one" and should not be limited to "only one" unless explicitly stated otherwise. Furthermore, the terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0087] The following examples are provided for illustrative purposes, and are not intended to limit the scope of this invention. Examples

[0088] The thermal induced stress has been calculated for different double glazing configurations comprising a VIG and a single glass pane that faces the exterior of the building. The single glass pane is separated from the VIG by a peripheral spacer of 15mm and the internal space is filled with argon. The single glass pane has a solar control coating, on its surface facing the internal space of the double glazing. The VIG comprises a first glass pane, GP1 and a second glass pane, GP2 that faces the internal space of the double glazing. The first glass pane has a low-emissivity coating on its surface facing the internal volume of the VIG. Examples 1 to 3 illustrate a multiple glazing comprising different embodiments of a laminated VIG. The examples 1 and 3 of the present invention demonstrate reduced thermal induced stress while meeting the safety and security requirements.

The thermal induced stress is calculated by an analytical linear solution at the conditions below and is the highest value obtained for the first and second glass panes. - Temperature: ΔT = -29°C. ΔT is calculated as the temperature difference between the mean temperature of the first glass pane, T1, and the mean temperature of the second glass pane, T2; - Glass panes are float annealed glass panes with a Young's modulus, E = 72GPa and a Poisson's ratio, μ = 0.21; and - Unconstraint edges, i.e. not positioned within a window frame.

[0089] Example 1 illustrates that when the first glass pane of the VIG within the double glazing has been laminated via an interlayer polymer to a first panel comprising a single glass sheet of 6mm so that the cubic root of the sum of the thickness(es) to the third power of the m glass sheet of the first panel and/or of the n glass sheet of the second panel (6mm), is equal to or lower than 126.7% of the sum of the thicknesses of the first glass pane and of the second glass pane (10.14mm), it reduces the thermal induced stress from 5.79MPa to 0.69MPa. Example 2 is a comparative example that illustrates that when such thickness relationship is not fulfilled (12mm > 10.14mm) it does not provide the technical benefit of reduced thermal induced stress. Example 3 further demonstrates that the benefit of reduced thermal induced stress is even greater when both panes of the VIG are laminated with panels comprising glass sheets of the same overall thickness (Zf ₁ = Zs ₁ ).