Patent Application
20180305972
The following disclosure relates to multi-pane vacuum insulating glass units (hereinafter “VIGUs” or “VIGs”) for use in fenestration applications (e.g., windows and doors for buildings), windows for transportation vehicles (e.g., buses, trucks, automobiles, planes, trains, and ships), solar collector panels; glass units for supermarket refrigeration systems, glass units for beverage vending machines, and other applications where insulating glass units having extremely high thermal insulation values are needed. In particular, it relates to VIGUs utilizing a glass-to-metal seal to hermetically seal the vacuum cavity between the panes and methods of assembling same.
Insulating glass units (also known as insulating glazing units or “IGUs” or “IGs”) and vacuum insulating glass units (also known as vacuum insulating glazing units or “VIGUs” or “VIGs”) are well known. Typical IGUs and VIGUs comprise two or more parallel but spaced-apart sheets of glass (also known as “panes” or “lites”) attached and/or sealed to one another around their respective peripheries. The enclosed gap between each pair of panes of glass defines a cavity bordered by the peripheral seal. In IGUs, the inter-pane cavity is filled with air or another insulating gas such as argon, krypton or xenon, whereas in VIGUs, the inter-pane cavity is “filled” with or contains a reduced-pressure atmosphere or a vacuum. Spacers (also known as “stand-offs,” “standoffs,” “pillars” or “suspenders”) may be disposed within the inter-pane gap of IGUs and VIGUs to maintain the gap and prevent the interior portions of the panes from touching one another in case of deflection. In the case of VIGUs, spacers are particularly necessary in order to support the panes of glass against the pressure of the outside air, which otherwise might distort or damage the glass, or cause the two adjacent panes of glass to come in contact with each other so as to produce a thermal “short circuit” (i.e., a thermally conductive path directly through the panes of glass).
Using vacuum to increase the insulating performance of window glazing components is not a new concept, and in fact many innovative approaches have been taught in the literature over the last 75 years. It is, however, readily observed by skilled practitioners of the art that the majority of the prior work relates to low-to-medium vacuum levels, i.e., vacuum levels within the range from about 760 torr (i.e., 1 torr=1 atmosphere of pressure at sea level) to about 10−3 torr. For purposes of this application, a “higher” level of vacuum is understood to correspond to a lower absolute pressure, e.g., a vacuum level of 10−4 torr is a higher vacuum than 10−3 torr. In a few cases the literature makes reference to the measured vacuum levels in glazing components, but in many cases the maintainable vacuum level must be interpreted from careful evaluation of the materials exposed to the vacuum enclosure, the methods used to create the vacuum seal and the methods used to produce the vacuum condition in the enclosed space.
While the literature describing vacuum insulating window glazing components may not rigorously define the vacuum levels, literature from other industries, such as the electronics industry, defines different vacuum levels and the types of materials and processing methods required to achieve and maintain those specified vacuum levels. The common distinction between medium-vacuum and high-vacuum devices is a vacuum level of 10−3 torr. In other words, the range of high-vacuum levels begins at about 10−3 torr and goes higher, i.e., in the direction toward and/or past 10−4 torr. In the case of VIGUs for windows, doors and other components, where it is desirable for the VIGUs to retain a prescribed minimum vacuum level for an extended operating lifetime (e.g., 25 years), a vacuum containment system capable of initially maintaining a higher level of vacuum (e.g., 10−5 torr), may be necessary.
High-vacuum insulating glass units (hereinafter “HVIGUs”) are VIGUs having a vacuum level in the inter-pane cavity of 10−3 torr or higher. One purpose of HVIGUs is to provide lower levels of conductive heat losses between temperature-controlled spaces and non-temperature-controlled spaces, or between different temperature-controlled spaces that are separated by this glazing unit (i.e., compared to VIGUs with low or medium-vacuum levels). In such cases, providing this desired lower level of conductive heat loss over a long period of time is desirable. Since the ambient conditions in the uncontrolled space, most commonly the external atmospheric environment, produce a variety of stresses including thermal, pressure and mechanical vibration, and since, to a lesser extent, this also happens in the conditioned space, various embodiments of the HVIGU will be more or less capable of surviving the applied stresses while maintaining the desired minimum vacuum level. Thus, the design lifetime, i.e., the period of time that the HVIGU will maintain its desired level of performance, is one of the performance features of the HVIGU.
In the case of VIGUs and HVIGUs, the periphery of the spaced-apart glass pane is sealed, typically along the edges, using some arrangement of sealing elements to isolate the evacuated inter-pane cavity from the surrounding atmospheric pressure. Since the primary objective of the VIGU or HVIGU is to provide a low thermally-conductive barrier between environmental spaces, each of which may have a higher or lower temperature with respect to the other, it is obvious to skilled practitioners of the art that the two panes of glass comprising a VIGU or HVIGU may reach temperature levels which vary distinctly from each other. In fact, for a given space-to-space temperature differential, the pane-to-pane temperature differential will typically increase as a function of reduced thermal conductivity of the VIGU or HVIGU. As a result of the temperature differential between the panes of glass, the panes may expand and contract differentially. This may also introduce differential movement of the spacers relative to one or both panes of glass.
For reference purposes, the outdoor-facing or outside-facing glass pane of an IGU/VIGU is typically referred to as lite #1, and the indoor-facing or inside-facing glass pane is typically referred to as lite #2. There are typically four glass surfaces of interest, denoted as surfaces 1, 2, 3 and 4. Surfaces 1 and 2 are, respectively, the outdoor-facing and indoor-facing surfaces of lite #1, and surfaces 3 and 4 are, respectively, the outdoor-facing and indoor-facing surfaces of lite #2. Thus, surfaces 2 and 3 are typically disposed on opposite sides of the inter-pane cavity of the IGU/VIGU/HVIGU.
As previously indicated, VIGUs are of interest for window applications because of their extremely high thermal insulating properties, with center-of-glass insulating or thermal resistance R values as high as R-13 or more, expressed in US units of British Thermal Units (i.e., BTUs) as ft2·cF·hr/BTU which equates to conductive U-Values or U-Factors of 0.07 BTU/(hr·° F·ft2) or lower as expressed in US units. The conversion between US and SI units of R-value is 1 ft2·° F·hr/BTU=0.176110 K·m2/W, or_1 K·m2/W=5.678263 ft2·° F·hr/BTU.
Generally speaking, a VIGU must maintain a pressure (i.e., vacuum level) of less than 1 millitorr (i.e., 1×10−3 torr) over its desired 10-40 year life in order to maintain its high R-value (low U value). As a result, the seals of the VIGU must provide a hermetic bond between surface 2 of lite #1 and surface 3 of lite #2. A VIGU seal is herein referred to as “highly hermetic” for a stated number of years if the seal has a leak rate low enough to maintain a vacuum in the associated inter-pane cavity of 1×10−3 torr or higher (i.e., higher vacuum) for at least the stated number of years. In other words, there is a leak rate associated with a highly hermetic VIGU seal, but the leak rate is such that, over the rated time period, the vacuum level in the associated cavity will fall from an initial value of vacuum that is higher than 1×10−3 torr to a final value of vacuum that is not lower than 1×10−3 torr.
U.S. Pat. No. 8,944,308 B2 to Friedl et al., entitled “Method And Apparatus For Producing Multiple-Pane Insulating Glass Having A High-Vacuum Insulation,” discloses an apparatus and method for producing an insulating structural element from substrates. The substrates may be connected to one another at a periphery by applied pieces and may be insulated from one another by a vacuum. U.S. Pat. No. 8,944,308 B2 is incorporated by reference herein.
International Publication No. WO 2014/205193, entitled “Low-Temperature Bonding And Sealing With Spaced Nanorods,” discloses improved systems and methods for low-temperature bonding and/or sealing with spaced nanorods. In certain embodiments, the bond is achieved at room temperature with only pressure or at a temperature above room temperature (e.g., about 150° C. or less) at reduced pressure. Exemplary bonds are both mechanically strong and substantially impermeable to oxygen and moisture. WO 2014/205193 claims benefit of U.S. Provisional Application No. 61/837,814, filed Jun. 21, 2013. Both International Publication No. WO 2014/205193 and U.S. Provisional Application No. 61/837,814 are incorporated by reference herein.
In one aspect, a vacuum insulated glass unit (VIGU) comprises a first lite of transparent or semi-transparent material with first and second surfaces and a second lite of transparent or semi-transparent material with third and fourth transparent surfaces. The lites are disposed such that the third surface faces the second surface, and the two surfaces are spaced apart to define an inter-lite gap between the second and third surfaces. A low emissivity coating is disposed on the entirety of the second and/or third surface except for an optional, edge-reduced region disposed in a continuous band around the perimeter of the second and/or third surface. At least one continuous band of metal-alloy solder hermetically bonds across the inter-lite gap between an interior portion of the optionally edge-reduced region of the second and/or third surface and an opposing region of the other surface to define a hermetically sealed cavity in a first portion of the inter-lite gap surrounded by the continuous band. A plurality of stand-offs are disposed within the cavity. An adhesive or epoxy material is disposed within a second portion of the inter-lite gap not surrounded by the continuous band and structurally bonds across the inter-lite gap between an exterior portion of the edge-reduced region of the second surface and an opposing region of the third surface.
In another aspect, a method for producing a VIGU as described above is provided that uses three soldering processes. In another aspect, a method for producing a VIGU as described above is provided that uses two soldering processes. In another aspect, a method for producing a VIGU as described above is provided that uses one soldering processes.
In another aspect, a method for producing a VIGU is provided that does not include an adhesive or epoxy material surrounding the continuous band of metal solder.
In a further aspect, a vacuum insulated glass unit (VIGU) comprises a first glass pane defining an interior surface and an exterior surface on opposite sides thereof and lateral edges extending therebetween and a second glass pane defining an interior surface and an exterior surface on opposite sides thereof and lateral edges extending therebetween. The second glass pane is disposed such that the interior surface of the second glass pane opposes the interior surface of the first glass pane, and the second glass pane further is spaced apart from the first glass pane to define an inter-pane gap between the opposing interior surfaces. A first band of metal solder extends continuously between the opposing interior surfaces of the first and second glass panes and is disposed continuously around the peripheries of the first and second glass panes but inset from the lateral edges of the first and second glass panes. An inter-pane cavity is defined in a first portion of the inter-pane gap that is surrounded by the first band of metal solder and a channel is defined in a second portion of the inter-pane gap that is between the first band of metal solder and the lateral edges of the glass panes. The first band of metal solder is attached with a first hermetic glass-to-metal bond to the interior surface of first glass pane and is attached with a second hermetic glass-to-metal bond to the interior surface of the second glass pane, whereby the inter-pane cavity is hermetically sealed with respect to the first and second glass panes. A plurality of stand-offs is disposed within the inter-pane cavity and extends between the opposing interior surfaces of the first and second glass panes. An adhesive material is disposed within the channel and extends between the opposing interior surfaces of the first and second glass panes and structurally bonds the first glass pane to the second glass pane across the inter-lite gap.
In one embodiment, the VIGU further comprises a low emissivity coating disposed on substantially all of the interior surface of the second glass pane except for an edge-reduced region disposed in a continuous band around the perimeter of the second pane. The second hermetic glass-to-metal bond from the first band of metal solder to the interior surface of the second glass pane is formed on a portion of the edge-reduced region.
In another embodiment, the VIGU further comprises a first relief cut formed in a portion of the interior surface of one of the glass panes bordering the lateral edge thereof, the first relief cut extending along the lateral edge, thereby reducing the thickness of the first-relief-cut portion of the glass pane by a first amount and increasing the thickness of the first-relief-cut portion of the inter-pane gap by the first amount. The adhesive material is disposed within the first-relief-cut portion of the inter-pane gap and the first band of metal solder is disposed in the remaining portion of the inter-pane gap. The thickness of the adhesive material is greater than the thickness of the first band of metal solder.
In yet another embodiment, a second relief cut is formed in a portion of the interior surface of one of the glass panes bordering the first relief cut, the second relief cut extending along the first relief cut, thereby reducing the thickness of the second-relief-cut portion of the glass pane by a second amount and increasing the thickness of the second-relief-cut portion of the inter-pane gap by the second amount, where the second amount is smaller than the first amount. The adhesive material is disposed within the first-relief-cut portion of the inter-pane gap and the first band of metal solder is disposed within the second-relief-cut portion of the inter-pane gap. The thickness of the first band of metal solder is greater than the thickness of the remaining interior portion of the inter-pane gap.
In still another embodiment, the first band of metal solder is formed from a solder alloy including tin (Sn), silver (Ag), titanium (Ti) and magnesium (Mg).
In a further embodiment, the VIGU further comprises a second band of metal solder extending continuously between the opposing interior surfaces of the first and second glass panes and continuously spaced apart from the first band of metal solder, whereby an inter-band gap is defined between the first and the second bands of metal solder. The second band of metal solder is attached with a third hermetic glass-to-metal bond to the interior surface of first glass pane and is attached with a fourth hermetic glass-to-metal bond to the interior surface of the second glass pane. The inter-pane cavity is further hermetically sealed with respect to the first and second glass panes.
In another embodiment, the lateral width of the inter-band gap between the first and second metal solder bands is within the range from 1 μm to 500 μm.
In yet another embodiment, the lateral width of the inter-band gap between the first and second metal solder bands is within the range from 500 μm to 1 mm.
In another aspect, a vacuum insulated glass unit (VIGU) comprises a first glass pane defining an interior surface and an exterior surface on opposite sides thereof and lateral edges extending therebetween and a second glass pane defining an interior surface and an exterior surface on opposite sides thereof and lateral edges extending therebetween. The second glass pane is disposed such that the interior surface of the second glass pane opposes the interior surface of the first glass pane. The second glass pane further is spaced apart from the first glass pane to define an inter-pane gap between the opposing interior surfaces. A first band of metal solder extends continuously between the opposing interior surfaces of the first and second glass panes and is disposed continuously around the peripheries of the first and second glass panes, whereby an inter-pane cavity is defined in a first portion of the inter-pane gap that is surrounded by the first band of metal solder. The first band of metal solder is attached with a first hermetic glass-to-metal bond to the interior surface of first glass pane and is attached with a second hermetic glass-to-metal bond to the interior surface of the second glass pane, whereby the inter-pane cavity is hermetically sealed with respect to the first and second glass panes. A plurality of stand-offs is disposed within the inter-pane cavity and extends between the opposing interior surfaces of the first and second glass panes.
In one embodiment, the VIGU further comprises a low emissivity coating disposed on substantially all of the interior surface of the second glass pane except for an edge-reduced region disposed in a continuous band around the perimeter of the second pane. The second hermetic glass-to-metal bond from the first band of metal solder to the interior surface of the second glass pane is formed on a portion of the edge-reduced region.
In another one embodiment, a VIGU further comprises a first relief cut formed in a portion of the interior surface of one of the glass panes bordering the lateral edge thereof, the first relief cut extending along the lateral edge, thereby reducing the thickness of the first-relief-cut portion of the glass pane by a first amount and increasing the thickness of the first-relief-cut portion of the inter-pane gap by the first amount. The first band of metal solder is disposed within the first-relief-cut portion of the inter-pane gap. The thickness of the first band of metal solder is greater than the thickness of the remaining interior portion of the inter-pane gap.
In yet another embodiment, the first band of metal solder is formed from a solder alloy including tin (Sn), silver (Ag), titanium (Ti) and magnesium (Mg).
In a still further embodiment, the VIGU further comprises a second band of metal solder extending continuously between the opposing interior surfaces of the first and second glass panes and continuously spaced apart from the first band of metal solder, whereby an inter-band gap is defined between the first and the second bands of metal solder. The second band of metal solder is attached with a third hermetic glass-to-metal bond to the interior surface of first glass pane and is attached with a fourth hermetic glass-to-metal bond to the interior surface of the second glass pane, whereby the inter-pane cavity is further hermetically sealed with respect to the first and second glass panes.
In another embodiment the lateral width of the inter-band gap between the first and second metal solder bands is within the range from 1 μm to 500 μm.
In a further embodiment, the lateral width of the inter-band gap between the first and second metal solder bands is within the range from 500 μm to 1 mm.
In another aspect, a method for making a vacuum insulated glass unit (VIGU) comprises providing a first glass pane defining an interior surface and an exterior surface on opposite sides thereof and lateral edges extending therebetween and providing a second glass pane defining an interior surface and an exterior surface on opposite sides thereof and lateral edges extending therebetween. A first band of metal solder is applied continuously around the periphery of the interior surface of the first glass pane but inset from the lateral edges of the first glass pane. A plurality of stand-offs is placed on the interior surface of the first glass pane disposed within the portion of the interior surface surrounded by the first band of metal solder. The second glass pane is positioned at a position proximate to, but spaced apart from, the first glass pane such that the interior surface of the second glass pane opposes the interior surface of the first glass pane to define an inter-pane gap between the opposing interior surfaces and defining an inter-pane cavity in that portion of the inter-pane gap surrounded by the first band of metal solder and defining a channel in that portion of the inter-pane gap between the first band of metal solder and the lateral edges of the glass panes. A first hermetic glass-to-metal bond is formed attaching the first band of metal solder to the interior surface of the first glass pane and a second hermetic glass-to-metal bond is formed attaching the first band of metal solder to the interior surface of second glass pane, whereby the inter-pane cavity is hermetically sealed with respect to the first and second glass panes. A structural adhesive is inserted into the channel, the structural adhesive extending between the opposing interior surfaces of the first and second glass panes and structurally bonding the first glass pane to the second glass pane across the inter-lite gap.
In one embodiment, the step of applying a first band of metal solder further comprises pre-tinning the interior surface of the first glass pane with a band of metal solder continuously around the periphery of the interior surface of the first glass pane.
In another embodiment, the step of applying a first band of metal solder further comprises placing solid pieces of metal solder around the periphery of the interior surface of the first glass pane.
In yet another embodiment, the step of forming a first hermetic glass-to-metal bond further comprises heating the first band of metal solder sufficient to liquefy at least portions of the first band of metal solder contacting the interior surface of the first glass pane continuously around the periphery of the first band of metal solder. Ultrasonic vibrations are applied to the liquefied portions of the solder of the first band of metal solder in contact with the interior surface of the first glass pane.
In still another embodiment, the step of forming a second hermetic glass-to-metal bond further comprises heating the first band of metal solder sufficient to liquefy at least portions of the first band of metal solder contacting the interior surface of the second glass pane continuously around the periphery of the first band of metal solder. Ultrasonic vibrations are applied to the liquefied portions of the solder of the first band of metal solder in contact with the interior surface of the second glass pane.
In a further embodiment, a second band of metal solder is applied on the interior surface of the first glass pane, the second band of metal solder being continuously spaced apart from the first band of metal solder, whereby an inter-band gap is defined between the first and second bands of metal solder. A third hermetic glass-to-metal bond is formed attaching the second band of metal solder to the interior surface of the first glass pane and a fourth hermetic glass-to-metal bond is formed attaching the second band of metal solder to the interior surface of second glass pane, whereby the inter-band gap is hermetically sealed with respect to the first and second glass panes.
In another aspect, a method for making a vacuum insulated glass unit (VIGU) comprises providing a first glass pane defining an interior surface and an exterior surface on opposite sides thereof and lateral edges extending therebetween and providing a second glass pane defining an interior surface and an exterior surface on opposite sides thereof and lateral edges extending therebetween. A first band of metal solder is applied continuously around the periphery of the interior surface of the first glass pane but inset from the lateral edges of the first glass pane and a second band of metal solder is applied continuously around the periphery of the interior surface of the second glass pane but inset from the lateral edges of the second glass pane. A plurality of stand-offs is placed on the interior surface of the first glass pane disposed within the portion of the interior surface surrounded by the first band of metal solder. The second glass pane is positioned at a position proximate to, but spaced apart from, the first glass pane such that the interior surface of the second glass pane opposes the interior surface of the first glass pane to define an inter-pane gap between the opposing interior surfaces and defining an inter-pane cavity in that portion of the inter-pane gap surrounded by the first band of metal solder and defining a channel in that portion of the inter-pane gap between the first band of metal solder and the lateral edges of the glass panes and further such that the first band of metal solder at least partially overlaps the second band of metal solder continuously around the periphery of the first band of metal solder. A first hermetic glass-to-metal bond is formed attaching the first band of metal solder to the interior surface of the first glass pane, a second hermetic glass-to-metal bond is formed attaching the first band of metal solder to the interior surface of second glass pane forming a second hermetic glass-to-metal bond attaching the first band of metal solder to the interior surface of second glass pane and a hermetic solder bond is formed attaching the first band of metal solder to the second band of metal solder, whereby the inter-pane cavity is hermetically sealed with respect to the first and second glass panes. A structural adhesive is inserted into the channel, the structural adhesive extending between the opposing interior surfaces of the first and second glass panes and structurally bonding the first glass pane to the second glass pane across the inter-lite gap.
In yet another aspect, a method for making a vacuum insulated glass unit (VIGU) comprises providing a first glass pane defining an interior surface and an exterior surface on opposite sides thereof and lateral edges extending therebetween and providing a second glass pane defining an interior surface and an exterior surface on opposite sides thereof and lateral edges extending therebetween. A first band of metal solder is applied continuously around the periphery of the interior surface of the first glass pane. A plurality of stand-offs is placed on the interior surface of the first glass pane disposed within the portion of the interior surface surrounded by the first band of metal solder. The second glass pane is positioned at a position proximate to, but spaced apart from, the first glass pane such that the interior surface of the second glass pane opposes the interior surface of the first glass pane to define an inter-pane gap between the opposing interior surfaces and defining an inter-pane cavity in that portion of the inter-pane gap surrounded by the first band of metal solder. A first hermetic glass-to-metal bond is formed attaching the first band of metal solder to the interior surface of the first glass pane and a second hermetic glass-to-metal bond is formed attaching the first band of metal solder to the interior surface of second glass pane, whereby the inter-pane cavity is hermetically sealed with respect to the first and second glass panes.
For a more complete understanding, reference is now made to the following description taken in conjunction with the accompanying Drawings in which:
For purposes of this application, although in appropriate usage vacuum insulating glazing units capable of maintaining vacuum levels of 10−3 torr or higher may be termed as “high-vacuum insulating glazing units” or “high-vacuum insulating glass units” (i.e., “HVIGU” or, in the plural, “HVIGUs”), this application will hereinafter refer to both vacuum insulating glazing units and high-vacuum insulating glazing units as VIGs or VIGUs.
Further for purposes of this application, unless otherwise specifically denoted, the term “ hermetic” as applied to a material or a seal shall mean that the material or seal has a helium leak rate less than or equal to 1×10−12 atm.·cc/sec. More preferably, a hermetic material or seal may have a helium leak rate less than or equal to 1×10−13 atm.·cc/sec. Still more preferably, a hermetic material or seal may have a helium leak rate less than or equal to 1×10−14 atm.·cc/sec. Even more preferably, a hermetic material or seal may have a helium leak rate less than or equal to 1×10−15 atm.·cc/sec.
Still further for purposes of the application, unless otherwise specifically denoted, the term “structural adhesive” shall refer to relatively strong adhesives that are normally used well below their glass transition temperature, an important property for polymeric materials, above which polymers are rubbery and below which they are glassy. Common examples of structural adhesives include, but are not limited to, epoxies, cyanoacrylates, toughened acrylics, polyurethanes, anaerobics, phenolics and vinyl acetates. Such adhesives can carry significant stresses, and lend themselves to structural applications.
In preferred embodiments of the described VIGU assemblies, the glass used for the panes or lites is tempered glass. It will be appreciated that while the use of tempered glass provides many mechanical and thermal advantages when used as the glass lites for a VIGU, annealed or heat-strengthened glass may also be used for the described construction of the VIGU assemblies. One advantage of using tempered glass for the panes of the VIGUs is that, due to the high surface compression of tempered glass, the stand-offs can be placed much further apart (from one another) than when using annealed or heat-strengthened glass. The thermal conductivity of a system or array of stand-offs is proportional to the square of the distance between the centers of the stand-offs. Thus, keeping all aspects of an individual stand-off constant, then doubling the distance between stand-offs (i.e., in both the X and Y dimensions) will reduce the thermal conductivity of the system of stand-offs by 75%. Put another way, doubling the distance between stand-offs will increase the thermal resistance of the system of stand-offs by a factor of 4 times. It is for this and other reasons, including many code requirements, that use of tempered glass for VIGUs is preferred.
Referring now to
Referring now also to
The metal seal 118 of the VIGU 100 may be inset by a distance, denoted DC, from the outer edges of the glass panes 102, 108 thereby defining a channel 120 extending laterally around the periphery of the VIGU. A layer of non-hermetic structural adhesive 122 may be provided in the channel 120. The structural adhesive 122 is bonded to the interior surfaces 106, 110 of the glass panes 102, 108 with a glass-to-adhesive bond. The mechanical strength of structural adhesive 122 with its glass-to-adhesive bond is one component of the overall mechanical bond between the two glass panes 102, 108, the second component being the mechanical strength of the metal seal 118 with its glass-to-metal bond.
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The VIGU 100 may further include a drilled hole 126 formed through one of the glass panes 102, 108 for subsequent placement of a vacuum septum for evacuating the inter-pane cavity 114 after the hermetic seals are established. In the illustrated embodiment, a evacuation hole 126 is provided on the second pane 108, however, in other embodiments a evacuation hole may be provided on the first pane 102. In still other embodiments, for example when the VIGU 100 is assembled in a vacuum, the VIGU 100 may not have a evacuation hole.
The VIGU 100 may further include a low-e coating 128 disposed on one or more surfaces 104, 106, 110, 112 of the glass panes 102, 108. The low-e coating 128 is typically provided on at least one of the interior surfaces 106, 110 to reduce the radiated energy between the two glass panes 102, 108 since the opposing interior surfaces are so close to one another.
In one embodiment of the VIGU 100, the hermetic cavity 114 is created using a metal seal 118 comprising one or more ultrasonically soldered active metal-alloy solders adhered to the opposing interior surfaces 106, 110 (i.e., surfaces 2 and 3) of the VIGU to create the hermetically sealed cavity between these two inside surfaces of the VIGU. The VIGU 100 of this embodiment also includes an array of stand-offs 116 that maintain the physical separation of the glass panes 102, 108 (i.e., lites #1 and #2), as well as a structural adhesive 122 or epoxy that surrounds the exterior of the hermetic solder seal 118 and is bonded to the opposing interior surfaces 106, 110 of the glass panes.
In one embodiment, the VIGU 100 has a low-e coating 128 extending over the entire cavity-facing surface 110 of the second glass pane 108. In another embodiment of the VIGU 100, the second glass pane 108 (lite #2) contains an edge-deleted low-e coating 128 on its cavity-facing surface 110, which is VIGU surface 3. Alternatively, the low-e coating 128 may be disposed on the first glass pane 102 (lite #1) on the cavity-facing surface 106, which is VIGU surface 2, or on both surfaces 2 and 3. The low-e coating 128 may be deleted (removed) from the edge of the lite 108 by relief cut 124, or by other means including physical abrasion and chemical solvents, to a distance towards the center of the lite at least as far as where the ultrasonically-soldered metal-alloy 118 will be applied. Whether or not this length of deletion is necessary depends on: 1) the adhesion properties of the low-e coating 128 to its glass surface 106, 110 (the low-e coating 128 must have sufficient shear and peel strength that it will not delaminate from the glass 102, 108 during the life of the VIGU 100 when the VIGU is used in its intended application and environment); 2) the adhesion strength in shear and peel of the chosen structural adhesive 122 to the low-e coating 128; and 3) whether an extremely hermetic solder bond can be achieved to the low-e coating 128 or through the low-e coating to the underlying glass surface 106, 110 by ultrasonically soldering an active solder to either the glass surface or to the low-e coating.
A preferred active solder for the metal seal 118 is a flux-free and lead-free solder called S-Bond 220M, produced by S-Bond Technologies, LLC of Lansdale, Pa. U.S.A. This solder is composed principally of Sn—Ag—Ti—Mg. Ultrasonic energy is used during soldering to allow/cause the solder to hermetically bond to glass 106, 110 or an appropriate low-e coating 128, thereby forming the metal seal 118. The preferred ultrasonic frequency range for soldering to glass 106, 110 or an appropriate low-e coating 128 using an active solder such as S-Bond 220M is within the range from 10,000 Hz to 40,000 Hz, although lower or higher frequencies may sometimes be used. In some other cases the ultrasonic frequency range is within the range from 10,000 Hz to 60,000 Hz.
As previously described, disposed within the inner perimeter of the soldered seal 118 is the array of stand-offs 116. In various embodiments of VIGU 100, ultrasonic application of the solder to surface 106 of glass pane 102 and positioning of the stand-offs 116 onto surface 106 may be performed in either order, i.e. first the placement of the stand-offs 116 onto the surface 106 of the lite 102 and then secondly, ultrasonically pre-tinning the surface of the lite 102; or alternatively, first ultrasonically pre-tinning the surface 106 of the lite 102 followed by placement of the stand-offs 116 onto the surface 106 of the lite 102. Surrounding the outer perimeter of the soldered seal 118 is the structural adhesive 122 or epoxy in the cavity or channel 120 that surrounds the hermetic soldered seal. The structural adhesive 122 or epoxy is bonded to the interior surfaces 106, 110 (VIGU surfaces 2 and 3). An optional hole 126 may be provided through one of the glass panes 102, 108 for a pump-out tube assembly. A pump-out tube assembly (not shown) is typically disposed proximate to one corner of the VIGU and is used to evacuate the hermetic cavity 114 contained between the VIGU surfaces 2 and 3 subsequent to formation of the hermetic cavity by use of the active metal solder to create the glass-to-metal seal 118.
According to literature released by S-Bond Technologies, LLC, the S-Bond® solders such as aforementioned S-Bond 220M solder feature the addition of titanium and/or rare earth elements to conventional solder alloy bases. It is believed that these active elements migrate to any interface and react or interact with the opposing material surface to either remove oxides and nitrides and transport them into the bulk of the solder as an inert material or adhere to them. It is believed that this process occurs while solder is molten, after the thin oxide “skin” that forms on the surface of the molten solder is broken, thus allowing contact between the bulk solder and the substrate surface. The breaking of this skin is referred to as “activation,” and is done by application of a low level of mechanical shear forces at the interface between the solder material and the substrate. The level of shear required is small and can be delivered by the application of high frequency vibration to the parts to be joined or to the bulk solder when it is molten.
The S-Bond 220M solder (and other preferred active solders) have a shear strength in the range of 5,000 psi to 6,000 psi and have high ductility, similar to other tin-silver solders. Hermeticity between the S-Bond 220M solder (and preferred active solders) and a substrate (e.g., glass panes 102, 108) can be achieved with bond line widths as low as 2 mm. The shear strength of adhesives and epoxies vary significantly.
For the VIGU 100, the ratio of the width of the metal seal 118 (which may be formed from relatively more expensive active solder) to the width of the structural adhesive 122 (which may be formed from relatively less expensive adhesive or epoxy), where the respective widths are measured in the direction parallel to the interior surfaces 106, 110 of the glass panes, depends on several variables, including but not limited to: 1) the desired width of the solder bond 118 to obtain sufficient hermeticity with an adequate safety factor (for end-use conditions, the size of the VIGU and the thermal environment in which it will be used); 2) the height TC of the pocket/channel 120 for the structural adhesive 122 and this height's interaction with the ease or difficulty of injecting an adhesive or epoxy into this material's cavity between the two lites of the VIGU; and 3) the optimization of the amount of active solder and adhesive or epoxy to achieve a low or the lowest cost for the combined use of both materials.
It will be appreciated that the advantages of using “active solder” for the metal seals 118 of the VIGU 100 in the embodiments illustrated in
With respect to
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Further in
Referring now to
In VIGU 200, for example, if a crack initiates (i.e., starts) in the hermetic glass-to-metal solder joint between one of the metal seals 218, 219 and one of the glass panes 102, 108, then this crack might eventually propagate (i.e., grow in length) and pass through the entire width of that respective solder bond joint. Although this event might cause a of loss of hermeticity for the respective one of the metal seals 218 or 219 in which the crack first occurred, the remaining metal seal would remain intact and vacuum tight. Further, the continuous gap 221 between the metal seals 218, 219 would halt the propagation of the crack so that it could not move into and damage the remaining metal seal. The gap 221 between solder bonds of the seals 218, 219 only needs to be wide enough to ensure physical separation between the two reflowed solder seals. In one embodiment of the VIGU 200, the lateral width of the inter-band gap 221 between the first and second metal solder bands 218, 219 is within the range from 1 μm to 500 μm. In another embodiment of the VIGU 200, the lateral width of the inter-band gap 221 between the first and second metal solder bands 218, 219 is within the range from 500 μm to 1mm.
The VIGU 200 further includes an array of spacers 116 inside the inner perimeter of the inner soldered metal seal 218. The structural adhesive 122 or epoxy surrounds and/or abuts the outer perimeter of the outer soldered metal seal 219. Although not shown, stand-offs 116 of an appropriate height to contact the interior surfaces 106,110 of the VIGU 200 may also be placed in the regions/channels 120 in which the structural adhesive 122 or epoxy is contained.
It will be appreciated that the VIGU 200 shown in
Referring now to
Referring first to
The first two soldering processes (i.e., the pre-tinning processes just described) may be performed in any order, e.g., the pre-tinning of the interior surface 106 may be performed first, or the pre-tinning of the interior surface 110 may be performed first, or the pre-tinning of both interior surfaces 106 and 110 may be performed simultaneously. Preferably, the two pre-tinning processes are performed using ultrasonically activated metal-alloy solder to form the pre-tinned metal elements 334, 336. Preferably, the metal-alloy solder of the respective pre-tinned metal elements 334, 336 is hermetically bonded to the respective interior surface 106, 110 of the glass lites 102, 108, or optionally, to the low-e coating 128 which may be on either or both surfaces 106 or 110.
Referring still to
Referring still further to
It will be appreciated that the application of ultrasonically applied metal-alloy solder may sometimes be referred to as “solder pre-tin”, but is also known by those skilled in the art by this and other names or terms including, but not limited to, “applying solder pre-tin,” “pre-tinning the surface of a lite” and “pre-tin soldering.” Additionally, the terms “pretin” and “pre-tin” are interchangeable as are “pretinning” and “pre-tinning.” Further, in the solid state of the active metal-alloy solder after the solder has been ultrasonically applied to the surface of one or both lites and the solder is allowed or forced to cool to solidification, this solid-state solder (as opposed to “liquid-state solder” or “molten solder”) is often referred to as “pre-tinned solder.” Additionally, the lite onto which the active solder has been ultrasonically soldered may be referred to as “the pre-tinned lite.” When the temperature of the pre-tinned lite is at or above the liquidus temperature of the metal solder, the pre-tinned solder might remain molten, depending on conditions surrounding the pre-tinned solder.
Referring yet further to
As previously described, after both lites 102, 108 have had their appropriate surfaces 106, 110 ultrasonically and hermetically solder pre-tinned to form the pre-tinned metal elements 334, 336, the VIGU 300 is pre-assembled by aligning the two lites so that the center of the top lite 108 is centered above the center of the bottom lite 102 and the pre-tinned solder 336 on the bottom surface 110 of the top lite is aligned above the pre-tinned solder 334 on the top surface 106 of the bottom lite. The alignment of the pre-tinned metal elements 334, 336 may be performed when the pre-tinned metal elements are in either a solid state or in a liquid state.
Referring now to
Referring now to
In some embodiments where the pre-tinned solders on one or both lites 102, 108 are still liquid and sufficiently hot when the pre-tinned metal elements 334, 336 are brought into contact with one another, the reflowing necessary to form the metal seal 118 having a hermetic glass-to-metal bond between the two interior surfaces 106, 110 may occur without adding more heat to one or both solder pre-tins. In other embodiments, additional heat and/or ultrasonic vibration energy must be applied to the pre-tinned solders on lites 102, 108 to cause the pre-tinned metal elements 334, 336 to combine and form a metal seal 118 having a hermetic glass-to-metal bond between the two interior surfaces 106, 110. Ultrasonic frequencies ranging from 10,000 Hz to 40,000 Hz may be used for the ultrasonic vibration as these frequencies are understood to break up any surface oxides on the pre-tinned surfaces of the earlier-applied solder pre-tins 334, 336 helping assure a hermetic soldered bondline between the interior surfaces 106, 110 of the two lites 102, 108. In some other cases the ultrasonic frequency is within the range from 10,000 Hz to 60,000 Hz. Once the two solder pre-tins 334, 336 have been combined to form a hermetic seal 118 and the interior surface 110 of the lite 108 is in contact with the top surfaces 342 of some or all of the stand-offs 116 inside the periphery of the resulting hermetic bondline, the solder bondline is allowed to cool (or made to cool) past the point of solidification.
After the hermetic glass-to-metal seal has been formed between the metal element 118 and the interior surfaces 106, 110 of the glass panes 102, 108, the resulting inter-pane cavity 114 may be evacuated via the evacuation hole 126 (e.g., using a septum) to create a vacuum in the cavity. The channel 120 between the lateral outer edges of the metal element 118 and the lateral edges of the glass panes 102, 108 may be filled with the structural adhesive 122 (
Referring now to
Referring first to
The pre-tinned metal element 434 has an associated original height HO measured from an inward-facing surface 438 to the surface 106 to which it is attached. Preferably, the original height HO is the minimum height of the pre-tinned metal element 434 around the entire continuous element. Similarly, each stand-off 116 has an associated height HS measured from an inward facing surface 442 of the stand-off to the surface 106 to which it is attached. Preferably, the original height HO of the pre-tinned metal element 434 is greater than the height HS of the stand-offs 116.
The order in which the solder 434 is ultrasonically applied to the lite 102 and the placement of the stand-offs 116 onto the surface 106 of the lite 102 can be performed in either order, i.e. first placing the stand-offs and then ultrasonically pre-tinning the surface 106 to form metal elements 434, or alternatively, first ultrasonically pre-tinning the surface of the lite and then placing the stand-offs onto the surface of the lite.
Referring now to
When the second glass pane 108 is moved into contact with the pre-tinned metal element 434, it will be appreciated that the upper surface 442 of the stand-offs 116 may not contact the interior surface 110 of the pane 108 (or alternatively, may not contact the low-e coating 128 of the pane, if present).
Referring now to
In some embodiments, ultrasonic energy may be applied to one or both lites 102, 108 when at least a portion of the solder of the pre-tinned metal element 434 is liquid and in contact with the interior surface 110 of lite 108, to cause the solder to become hermetically bonded to the interior surface 110. The interior surface 110 may or may not have a low-e coating 128 on the glass where the solder of the metal element 434 is bonded to the surface 110.
During reflowing, pressure may be applied to bias the two panes 102, 108 towards each other while the solder of the pre-tinned metal element 434 is liquid, thereby causing the two panes to move until the interior surface 110 (including any low-e coating 128 or other performance enhancing coating thereon) contacts the top surfaces 442 of some or all of the stand-offs 116. This applied pressure may be supplied by the weight of second pane 108, or by an outside force applied perpendicular to the first outer surface 104, or by an outside force applied perpendicular to the second outer surface 112, or some combination of external forces applied perpendicular to both surfaces 104 and 112. During reflowing, the pre-tinned metal elements 434, which have the original height HO, at least partially melt and subsequently solidify into the continuous metal seal 118, which has the final height HF, where the value of HF is less than the value of HO. It is believed that allowing the final height HF of the metal seal 118 to be determined by actual contact of the interior surfaces 106, 110 with the stand-offs 116 while the material of the seals is liquid provides VIGU 400 with improved tolerance for variation in the thickness of the glass panes 102, 108 and for variation in the height of the stand-offs 116 compared with VIGUs having a predetermined seal height.
In some embodiments, after the pre-tinned metal element 434 of active metal-alloy solder has been completely ultrasonically bonded to the interior surface 110 of pane 108 during reflowing (having been previously bonded to the interior surface 106 of pane 102), the solder is allowed, or alternatively forced, to cool to a temperature at or below its associated solidification temperature (thereby becoming the metal seal 118). Allowing or forcing the solder to cool to or below its solidification temperature in a timely manner may require forced partial cooling of first lite 102 and/or second lite 108, or another method to cause the solder to become solid.
After the hermetic glass-to-metal seal has been formed between the metal seal element 118 and the interior surfaces 106, 110 of the glass panes 102, 108, the resulting inter-pane cavity 114 may be evacuated via an evacuation hole 126 (e.g., using a septum) to create a vacuum in the cavity. The channel 120 between the lateral outer edges of the metal element 118 and the lateral edges of the glass panes 102, 108 may be filled with the structural adhesive 122 (
Referring now to
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An array of stand-offs 116 are placed on the same interior surface 106 of the glass pane 102 as the pre-placed solder band or pieces 534 and within the inside periphery of the solder piece or pieces. Preferably, the pre-placed solder pieces 534 have an original height, HO, which is greater than the height, HS, of the stand-offs. The order in which the solder band or pieces 534 are placed onto the surface 106 of the pane relative to the placing of the stand-offs 116 onto the same surface can be performed in either order, i.e., first placing the stand-offs 116 and then placing the solid solder pieces 534 onto the surface of the lite, or alternatively, first placing the solid solder pieces 534 onto the surface of the lite and then placing the stand-offs 116 onto the surface of the lite.
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Preferably, the temperature of the glass panes 102, 108 in the region to be soldered to the solder band/pieces 534 is at or above the liquidus temperature of the solder in the band/pieces. If not, heat may be applied to either or both glass panes 102, 108 or the to-be-soldered contact surfaces 106, 110 in order to raise the temperatures of these surfaces. In some embodiments, ultrasonic energy may be applied to one or both lites 102, 108 when at least a portion of the solder of the solder band/pieces 534 is liquid and in contact with the interior surfaces 106 and/or 110, to cause the solder to become hermetically bonded to the interior surfaces 106 and 110. The interior surfaces 106 and 110 may or may not have a low-e coating 128 on the glass where the solder of the band/pieces 534 is bonded to those surfaces.
During reflowing, pressure may be applied to bias the two panes 102, 108 towards each other while the solder of the pre-placed solder pieces 534 is liquid, thereby causing the two panes to move until the interior surface 110 (including any low-e coating 128 or other performance enhancing coating thereon) contacts the top surfaces 542 of some or all of the stand-offs 116. This applied pressure may be supplied by the weight of second pane 108, or by an outside force applied perpendicular to the first outer surface 104, or by an outside force applied perpendicular to the second outer surface 112, or some combination of external forces applied perpendicular to both surfaces 104 and 112. During reflowing, the pre-placed solder pieces 534, which have the original height HO, at least partially melt and subsequently solidify into the continuous metal seal 118, which has the final height HF, where the value of HF is less than the value of HO. It is believed that allowing the final height HF of the metal seal 118 to be determined by actual contact of the interior surfaces 106, 110 with the stand-offs 116 while the material of the seals is liquid provides VIGU 500 with improved tolerance for variation in the thickness of the glass panes 102, 108 and for variation in the height of the stand-offs 116 compared with VIGUs having a predetermined seal height.
In some embodiments, after the pre-placed solder pieces 534 of active metal-alloy solder are completely ultrasonically bonded to the interior surfaces 106 and 110 of panes 102 and 108, respectively, during reflowing, the solder is allowed, or alternatively forced, to cool to a temperature at or below its associated solidification temperature (thereby becoming the continuous metal seal 118). Allowing or forcing the solder to cool to or below its solidification temperature in a timely manner may require forced partial cooling of first lite 102 and/or second lite 108, or another method to cause the solder to become solid.
After the hermetic glass-to-metal seal has been formed between the metal seal element 118 and the interior surfaces 106, 110 of the glass panes 102, 108, the resulting inter-pane cavity 114 may be evacuated via the evacuation hole 126 (e.g., using a septum) to create a vacuum in the cavity. The channel 120 between the lateral outer edges of the metal element 118 and the lateral edges of the glass panes 102, 108 may be filled with the structural adhesive 122 (
Referring now to
Referring first to
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If the shape of the lites of the VIGU are non-rectangular, then one or more active metal-alloy solder ribbons 602-610 or combination of multiple pieces of solder ribbon may be used to conform to the outline shape of the VIGU.
Referring still to
In yet another embodiment (not shown), a continuous hermetic metal seal having a glass-to-metal bond may be formed by depositing an active solder in its liquid or molten state onto the interior surface (e.g., surface 106 or 110) of one or more glass panes (e.g., panes 102 or 108) to be incorporated into a VIGU. Ultrasonic vibration may be applied to the liquid solder and/or glass panes during bonding of the solder to increase the hermeticity and/or strength of the resulting glass-to-metal bond.
In yet another embodiment (not shown), an active solder in its liquid or molten state may be droplet-jetted (in a fashion similar to ink-jetting) onto the interior surface (e.g., surface 106 or 110) of one or more glass panes (e.g., panes 102 or 108) to be incorporated into a VIGU. Ultrasonic vibration may be applied to the liquid solder and/or glass panes during bonding of the solder to increase the hermeticity and/or strength of the resulting glass-to-metal bond.
In yet another embodiment (not shown), a so-called “metallic glue” such as one of the low-temperature nanorod-based metallic adhesive materials described in International Publication No. WO 2014/205193 (incorporated by reference herein), entitled “Low-Temperature Bonding And Sealing With Spaced Nanorods,” may be substituted for one or both of the pre-tinned metal elements 334, 336 of the VIGU 300, for the pre-tinned metal element 434 of the VIGU 400, for the pre-placed solder band/pieces 534 of the VIGU 500 and/or for the solder ribbon pieces 602-610 of the VIGU 600. In certain embodiments, the use of the metallic glue may allow hermetic glass-to-metal bonds to be achieved at room temperature with only pressure or at a temperature above room temperature (e.g., about 150° C. or less) at reduced pressure. It is understood that such bonds may be both mechanically strong and substantially impermeable to oxygen and moisture.
Referring now to
It will be appreciated that the VIGU 700 may be assembled using any of the assembly methods described herein in connection with VIGUs 300, 400, 500 and 600, except that the application of the structural adhesive is omitted after the metal seal has been hermetically bonded to the glass panes.
Although the preferred embodiments have been described in detail, it should be understood that various changes, substitutions and alterations can be made therein without departing form the spirit and scope of the invention as defined by the appended claims.
This application is a 371 of International Application No. PCT/US16/17626, filed on Feb. 11, 2016, entitled VACUUM INSULATED GLASS UNIT WITH GLASS-TO-METAL SEAL AND METHODS OF ASSEMBLING SAME (Atty. Dkt. No. STRK-32916), which published as WO 2016/130854 on Aug. 18, 2016. Application No. PCT/US16/17626 claims priority to and/or benefit of U.S. Provisional Application No. 62/115,108, filed Feb. 11, 2015, entitled EDGE SEAL ASSEMBLIES FOR HERMETIC VACUUM INSULATING GLASS UNITS AND METHODS OF ASSEMBLING SAME (Atty. Dkt. No. STRK-32518), U.S. Provisional Application No. 62/157,290, filed May 5, 2015, entitled VACUUM INSULATED GLASS UNIT AND METHOD (Atty. Dkt. No. STRK-32600), and U.S. Provisional Application No. 62/157,299, filed May 5, 2015, entitled VACUUM INSULATED GLASS UNIT AND METHOD (Atty. Dkt. No. STRK-32601). Application Nos. PCT/US16/17626, 62/115,108, 62/157,290 and 62/157,299, and Publication No. WO 2016/130854 are incorporated by reference herein in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US16/17626 | 2/11/2016 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62115108 | Feb 2015 | US | |
| 62157290 | May 2015 | US | |
| 62157299 | May 2015 | US |
