Abstract:
An architectural building panel comprises a sealed glazing unit having at least two spaced apart parallel glazing sheets which define a cavity closed by a peripheral seal. Opaque strip elements on the building panel provide the appearance of window frames surrounding transparent glass areas, with regions of the panel outside these frames being provided with surface area patterns that simulate the appearance of conventional building materials such as brick or the like. The building panel can be used in any convenient size, and may be of a size to extend between structural floors of a building so that a curtain wall for the building can be composed of exteriors of such building panels.

Description:
PRIOR ART 
     
       
         
               
               
             
               
               
               
               
               
             
           
               
                   
                   
               
               
                   
                 U.S. Pat. Nos. 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 4,598,520 
                 July 1986 
                 Ellstrom 
                  52/456 
               
               
                   
                 4,968,553 
                 November 1990 
                 Cesar 
                 428/203 
               
               
                   
                 5,465,539 
                 November 1995 
                 Rose 
                  52/204.53 
               
               
                   
                 5,494,715 
                 February 1996 
                 Glover 
                 428/34 
               
               
                   
                   
               
             
          
         
       
     
     INTERNATIONAL PATENTS 
     WO 95 15267 Stained, Glass Systems 
     WO 98 43832 Pearson 
     FIELD OF INVENTION 
     This invention relates generally to architectural building panels and more specifically to building panels that incorporate multiple pane sealed glazing units with decorative features. 
     DESCRIPTION OF THE PRIOR ART 
     Conventional curtain wall cladding systems are non-load bearing walls that are suspended in front of a main structural frame of a building. Typically, a curtain wall system consists of a rectangular grid of vertical and horizontal metal framing members with infill panels of clear vision glass and opaque insulating panel assemblies that can be clad with a metal, tile, stone or glass facing. 
     Particularly in cold weather climates, there are a number of performance drawbacks with these conventional curtain wall systems. There are four main issues: 
     1. Because of a metal grid framing system, there can be substantial conductive heat loss particularly through the framing system and at perimeter edges of glazing units and panel assemblies. 
     2. Because of a multi-component panel assembly, a jointing design for an air barrier and rain screen system can be very complex and prone to failure. 
     3. Particularly for elaborate heritage window designs, on-site installation can be very labor intensive. 
     4. Because of the need to insulate a panel wall assembly, potential rentable interior space is reduced. 
     In U.S. Pat. No. 5,494,715 issued to Glover, there is a description of various efforts that have been made in recent years to improve both energy efficiency and condensation resistance of multiple glazed sealed units. These improvements include: low-e coatings, argon or krypton gas fill, insulating spacing-and-desiccant systems for perimeter edge seals and narrow-width cavities (approximately ⅜″ spacing for argon gas filled units). 
     As also noted in U.S. Pat. No. 5,494,715, there is a growing consumer interest in heritage window features and these window features can include colonial style divided-lite windows, leaded or stained glass windows and decorative sun screens. These decorative features can be very labor intensive to produce and to simplify production, Glover describes how visual illusion of these features can be created by virtue of decorative stripe patterns that are applied to two or more glazing sheets of a multiple glazed unit. Because of potential durability problems, material of the stripe patterns must be non-outgassing and with high volume production methods, experience has shown that for typical coating materials, this is a very demanding technical requirement. 
     Various efforts have also been made to simulate the appearance of traditional building materials. U.S. Pat. No. 4,968,553,issued to Cesar, describes how a graphic laminate is created by heat laminating a printed sheet of extruded polyurethane between two plates of glass, using a conventional autoclave process. In WO 95/15267 issued to Stained Glass Systems, an alternative method for producing decorative glass panels is described by which ceramic decals with printed designs simulating marble or other materials are applied to a glass sheet which is then heated so that ceramic material of the decals is fused to the glass sheet. In producing large decorated glass panels, a series of ceramic transfers are placed side-by-side. However, because of a need for high accuracy, this process is very labor intensive and cannot be easily automated. 
     In WO 98/43832, issued to Pearson, automated equipment for applying ceramic decals is described wherein heat release decals on a decal carrier are laminated onto glass sheets. Unlike an automated decal stamp pad equipment developed by Service Engineers for Stained Glass Systems, (See Product Literature: Fully Automated Multi-Color Glass Decorative Machine Designed for In-line Production, Stained Glass Systems, September 1996), decals are applied through a roller press system where glass sheets continuously pass through a laminating station. 
     Although large sized panels can be produced by this method, individual large scale decals are conventionally printed and their manufacturing process is not suitable for production of one-off custom products. 
     DE-U-295 05 223.6 discloses a building door that has an insulating glazing unit mounted in a casement frame. The glazing unit has two spaced apart parallel co-extensive glazing sheets sealed together at their peripheries. The sheets define a transparent window area that is surrounded by registering frames formed of plastic or metal and bonded to outer sides of the two sheets. An area of a door between the peripheries and the attached frames surrounding the transparent area is covered on each of the glazing sheets by a layer of opaque material which can be provided by various methods. 
     SUMMARY OF THE INVENTION 
     The invention provides an architectural building panel in the form of a sealed glazed unit comprising: at least two spaced apart parallel coextensive glazing sheets; peripheral seals extending continuously between edges of the glazing sheets to define an insulating cavity between adjacent glazing sheets. Each of the glazing sheets has a transparent area, wherein the transparent areas of respective sheets are in alignment to define a window region, and also has surface area patterns on part of at least two surfaces of the glazing sheets. Opaque strip elements are located on surfaces of two of the glazing sheets, with the opaque strip elements surrounding the transparent area of an associated one of the glazing sheets, and wherein strip elements on different surfaces are in mutually aligned registration with each other and have a width extending parallel to the glazing sheet surfaces that is sufficient to create a visual illusion of a solid member within a cavity. The combination of the transparent areas and the surface area patterns simulates the appearance of a window incorporated within a building wall. 
     Between a window region and peripheries of the panel, the surface area patterns on the two glazing sheets preferably comprise overlapping patterns that collectively simulate the appearance of a traditional building material, with exterior glazing sheet patterns including transparent areas and adjacent interior glazing sheet patterns registering at least partially with the transparent areas of the exterior glazing sheet patterns. 
     The sealed glazed unit consists of two or three glazing sheets that define one or two glazing cavities that are preferably filled with argon gas for improved energy efficiency. Also to provide for improved energy efficiency, a low-e coating is preferably incorporated on at least one surface of the glazing cavities. 
     Strip patterns may preferably define window frames surrounding the transparent area, and around the frames surface area patterns may be designed to simulate almost any kind of surface finish, and in particular the appearance of traditional building materials such as bricks, stone, granite, marble and clay tile, and the like, including mortar joints and the like. 
     The surface area patterns can be provided in any suitable manner, e.g.: by use of ceramic frit materials that can be deposited on glass by virtue of heat transfer decals in roll or strip form; by printing patterns on flexible plastic film material laminated onto a cavity surface of one or more of the glazing sheets; or by printing patterns on flexible plastic film material from which surface area patterns can be transferred to a plastic coating on one or more of the glazing sheets by virtue of a dye sublimation process. 
     The opaque strip elements can similarly be provided in many ways, e.g.: by use of ceramic frit material; by printing on flexible plastic film material; by use of strips of flexible plastic sheet material adhered to glass by virtue of a pre-applied pressure sensitive adhesive on strips; or by use of shaped form members adhered to exterior surfaces of the glazing sheets. In the latter case, the shaped form members can be vacuum formed from plastic sheet material or may comprise hollow linear profiles. The shaped form members can be adhered to the glazing sheets by virtue of double sided adhesive foam tape or by other manners. 
     However provided, the opaque strip elements are preferably designed to have one side that is of a relatively light shade and an opposite side that is of relatively dark shade, and are attached to the glazing sheets in an orientation such that the side of the relatively dark shade is adjacent to the glazing cavity. This, in conjunction with relatively close spacing of the glazing sheets, creates an illusion that the opaque strip elements constitute solid window frame elements extending through the building panel. 
     Building panels as described herein are useful in many applications. One notable example is their potential for use in providing a curtain wall structure in multi-story buildings. In this application, a panel will be sized to span a distance between structural floors of a building. The glazing sheets will preferably be of heat strengthened or tempered glass. Also, it is advantageous for the exterior glass sheet of the building panel to be slightly enlarged, i.e. to have perimeter edges that extend slightly beyond edges of the other glazing sheet or sheets, thereby providing peripheral support flanges. Rigid channels can be adhered to the support flanges by virtue of silicone sealant, and these channels can suitably be fibreglass. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The following is a description by way of example of certain embodiments of the present invention, reference being made in the accompanying drawings, in which: 
     FIG. 1 is a fragmentary exterior perspective view showing an architectural building panel that simulates the appearance of a window incorporated within a brick wall. 
     FIG. 2 is a vertical cross-sectional view of the architectural building panel taken generally on the line II—II in FIG. 1 showing the panel extending between structural floors of a high-rise building. 
     FIG. 3 is an enlarged vertical cross-sectional detail of the region indicated by the circle A in FIG. 2 showing a simulated window/wall junction; 
     FIG. 4 is an enlarged vertical cross-sectional detail of the region indicated by the circle B in FIG.  2  and showing a jointing system between two building panels and an interface with a metal grid structure; 
     FIG. 5 is a partially exploded perspective view of an architectural building panel that simulates the appearance of a traditional heritage window incorporated within a brick wall. 
     FIG. 6 is a fragmentary perspective view of a triple-glazed unit that simulates the appearance of marble, wherein there are different patterns on different surfaces of the triple-glazed unit. 
     FIGS.  7 ( i )- 7 ( v ) are series of fragmentary plan views of production steps for producing ceramic decorative patterns on a glass sheet. 
     FIG. 8 is a fragmentary perspective view of a double-glazed building panel that graphically simulates the appearance of a window incorporated within a brick wall 
     FIG. 9 is an enlarged cross sectional detail of the double-glazed building panel illustrated in FIG. 8 as seen on the line VIII—VIII. 
     FIG. 10 is a fragmentary perspective view of a double-glazed building panel, with attached linear hollow profiles, that simulates the appearance of a window within a brick wall. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 is a fragmentary exterior perspective view of an architectural building panel  20  that simulates the appearance of a window incorporated within a simulated brick-clad building wall. 
     The panel  20  consists of a triple-glazed sealed unit  21  that incorporates a transparent area  22  and surrounding exterior surface patterned area  23  (area pattern) that simulates the appearance of clay bricks. Located between the transparent area  22  and the exterior surface patterned area  23  are opaque strip elements  24  that simulate the appearance of window frame profiles. 
     FIG. 2 shows a vertical cross section of the architectural building panel  20  taken generally on the line II—II in FIG. 1 showing the panel  20  extending between structural floors  25  and  26  of a high-rise building  27 . The panel  20  incorporates a triple-glazed sealed unit  21  that is structurally adhered to a metal grid framing system  28  that is mechanically connected to the building&#39;s main structural floors  25  and  26 . 
     FIG. 3 shows an enlarged vertical cross section detail of the region indicated by the circle A in FIG.  2 . The triple-glazed sealed unit  21  consists of an exterior glass glazing sheet  30 , an interior glass glazing sheet  31  and a center glass glazing sheet  32 . Surface patterned areas  23  and  33  are applied to cavity surfaces  34  and  35  of the exterior and interior glazing sheets  30  and  31 , respectively. 
     Surface patterned area  33  (area pattern) consists of an opaque decorative surface coating  37  which is typically a light shade that is generally backed by a second surface coating  38  that is typically a dark shade. 
     Surface patterned area  23  consists of rectangular opaque areas  43  on the cavity surface  34 . Between the rectangular opaque areas  43 , there are transparent margin areas  44  such that when the combined patterns are viewed at an angle, a three dimensional illusion is created of a brick wall with traditional mortar joints. 
     The rectangular opaque areas  43  located on the exterior glazing sheet  30  can be textured with transparent voids within the surface pattern, and an optional surface coating  45  can be applied to the center glazing sheet  32 . The optional surface coating  45  on the center glazing sheet  32  can be a different color such that when viewed from the exterior, three patterns in combination create the illusion of a textured surface. 
     Although a brick wall surface is shown in FIG. 3, it can be appreciated by those skilled-in-the-art that the visual appearance of various other traditional building materials can be simulated including stone, granite, marble and clay tiles. 
     The surface coating  45  and surface patterned areas  23 ,  33  are fabricated from ceramic frit material that is fused to the glass glazing sheets  30 ,  31  and  32  at high temperatures. After ceramic coatings have been applied and the glass glazing sheets  30 ,  31  and  32  have been tempered, sputtered low-e coatings  40  and  41  can be applied to the cavity surfaces  34  and  35 . Although transparent, the low-e coatings  40  and  41  reduce radiative heat loss across glazing cavities  52  and  53 . To further reduce conductive heat loss, the glazing cavities  52  and  53  can be filled with argon gas. A width of the glazing cavities is typically about 12.5 mm; however, if a decorative window design incorporates narrow muntin bars or other similar details, the width can be reduced to ⅜″ or less. 
     A width of the triple-glazed unit  21  is typically less than 2 inches. However, because of various energy efficient features such as low-e coatings and argon gas, and also because there is reduced perimeter heat loss through window frames and spandral panels, such a narrow width unit provides comparable insulating performance relative to a conventional curtain wall assembly where a width or thickness of a wall of the assembly is typically at least 6 inches. This potential reduced wall thickness is important because under most building zoning regulations, the allowable size of a building is determined based on exterior building dimensions while rentable space is determined based on interior building dimensions. Specifically, when a slim wall cladding system is retrofitted to an existing building, rentable space can be increased resulting in increased revenue to the building owner. 
     Typically, the exterior glass glazing sheet  30  is thicker than the interior and center glass glazing sheets  31  and  32 , and this helps ensure that the exterior glass glazing sheet remains flat and does not bow inwards or outwards due to pressure changes within the glazed sealed unit  21 . 
     Opaque strip elements  24  are applied at boundary areas  44  between transparent glazing areas  22  and the surface patterned areas  23  and  33 . The opaque strips  24  are generally in register with each other. Generally, outwardly facing sides  58  and  59  of the opaque strip elements  24  are of a light shade while inwardly facing sides  60  and  61  of the opaque strip elements are typically of a dark shade with black being the preferred color. 
     The opaque strip elements  24  are of a sufficient width such that when viewed at an oblique angle, a visual illusion is created of a solid framing member that spans between the glass glazing sheets  31  and  30 . Depending on a width of the opaque strip elements  24 , an optional flat strip  62  can be applied to the center glass glazing sheet  32 . The opaque strip elements  24  can be made from various materials and as shown in FIG. 3, one option is for the opaque strip elements to be made from hollow linear profiles  55  that are adhered to outwardly facing sides of the glass glazing sheets  30  and  31  with two-sided adhesive foam tapes  57 . The hollow linear profiles  55  are made from aluminum, but various other materials can be used including: fibreglass, PVC plastic and wood. Typically, the two-sided adhesive foam tape is made from polyethylene foam and acrylic is the preferred material for a pressure sensitive adhesive. 
     FIG. 4 is an enlarged vertical cross section detail of the region indicated by the circle B in FIG.  2 . There are two adjacent triple-glazed sealed units  21  and  63  that are both structurally connected to a metal support frame  64 . The triple-glazed sealed units  21  and  63  are sealed at their perimeter edges using a tri-seal combination consisting of an inner flexible desiccant-filled foam spacer  65  that is structurally adhered to the glass glazing sheets  30 ,  31  and  32 ; an outer layer of structural thermosetting silicone sealant  66 , and a layer of hot melt thermoplastic butyl  67  or polyisobutylene sealant sandwiched between the foam spacer  65  and silicone sealant  66 . A key advantage of this tri-seal design is that as the glass glazing sheets  30 ,  31  and  32  flex back and forth, a butyl moisture/barrier seal remains firmly held against the glass glazing sheets  30 ,  31  and  32 , and this ensures outstanding edge seal durability. 
     The exterior glass glazing sheet  30  extends about one inch beyond the edge seal, thus creating a perimeter flange  69 . A fibreglass channel  68  is structurally adhered to perimeter flange  69  using structural silicone sealant  70 . The fibreglass channel  68  is mechanically connected to the support frame  64  by virtue of a swivel toggle connector  71  and bolt  72 . An outer rain screen joint between the two triple-glazed sealed units  21  and  63  is sealed by hollow silicone rubber extrusions  73  adhered to perimeter edges  74  of respective glass glazing sheets  30 . Two inner air seal joints between the metal support frame  64  and the triple-glazed sealed units  21  and  63  are sealed by silicone sealant  75 . 
     FIG. 5 is a partially exploded perspective view of an architectural building panel  20  that simulates the appearance of a traditional heritage window incorporated within a simulated brick wall. Building panel  21  consists of a double glazed unit  76  with a window attachment  47  that is adhered to the double-glazed unit with double sided pressure sensitive adhesive sheet foam. To provide for additional structural support, silicone sealant can also be used as a structural seal between the window attachment  47  and exterior glazing sheet  30 . The window attachment  47  is made from plastic sheet material such as polyethylene that is vacuum formed, and which is coated with a durable material such as a fluoro elastomer coating. For improved rigidity, the window attachment  47  can be foam filled with a light rigid foam material such as polyurethane. 
     FIG. 6 is a fragmentary perspective view of a triple-glazed unit that simulates the appearance of polished marble stone. Exterior glazing sheet  30  incorporates a series of decorative patterns  78  that are located on glazing cavity face  34  and which simulate in part the appearance of specific colored features of a particular marble stone. 
     Center glazing sheet  32  incorporates a second and different series of decorative patterns  79  that also simulate the appearance of other features of the marble stone. Third interior glazing sheet  31  can also incorporate a third and different series of decorative patterns  80  that are located on glazing cavity surface  35 , and that also simulate the appearance of additional colored features of a particular marble stone. Particularly when viewed at a distance, the three overlapping decorative patterns  78 ,  79  and  80  collectively simulate a rich textured appearance of polished marble. 
     Although a marble surface pattern is given as an example in FIG. 6, it can be appreciated by those skilled-in-the-art that other decorative textured surface finishes can also be simulated with different surface patterns being applied to multiple glazing sheets. 
     Ceramic decorative patterns shown in FIGS. 1-6 can be produced in various ways. One option is to directly apply the ceramic patterns to the glazing sheets using conventional silk screen printing processes. However, because of limitations of silk screen printing processes, there is a need for relatively high volume printing runs and as a result, building panel designs generally have to be standardized. 
     A second option is to produce the ceramic decorative patterns using a single large scale decal that is applied using a heat transfer process. Again, because of limitations of decal printing processes which are presently available, building panel designs generally have to be standardized. However, in the future these limitations may be overcome with development of ink jet printers suitable for ceramic inks. 
     A third option is to assemble the decorative patterns from a series of decal strips that are separately applied to a glazing sheet while the glazing sheet is in a stationary position. A width of the decal strips can vary and can be as wide as typical wallpaper rolls. The decal strips can be produced by various printing processes, and one preferred option is to use a rotor gravure process. 
     FIGS.  7 ( i )- 7 ( v ) show a series of fragmentary plan views of production steps for producing custom decorative patterns of ceramic frit material on a glass sheet  31  that is in a stationary position. 
     FIG.  7 ( i ) shows application of a single decal strip  81  incorporating opaque rectangular patterns  43 , wherein the strip  81  is applied using a heated roller that moves horizontally or vertically across the glass sheet  31 . 
     FIG.  7 ( ii ) shows application of a second decal strip  82  incorporating opaque rectangular patterns  43 , that is located about a half inch away from the strip  81 , and wherein transparent margins  84  between rectangular patterns of the strip  82  are located at about a center line of the rectangular patterns  43  on the decal strip  81 . 
     FIG.  7 ( iii ) shows application of a third decal strip  85 , wherein the strip is cut off at a mid point  86  of a second rectangular pattern. 
     FIG. 7 ( iv ) shows application of additional decal strips  87  that are cut off to form a transparent area  23 . Because the opaque rectangular patterns are separated by a transparent margin, there is no need to very accurately match up the patterns at decal edges, and large customized panel designs can be easily and efficiently manufactured. A width of the decal strips can vary and can be as wide as a typical wallpaper roll, with wider strips incorporating a series of rectangular patterns side by side. 
     FIG.  7 ( v ) shows application of an optional perimeter strip  88  around a perimeter of the transparent area  23 . The perimeter strip  88  is of ceramic frit material and can feature one side that is a light shade and another side that is a dark shade. 
     FIG. 8 is a perspective view of an architectural building panel  20  that simulates the appearance of a window incorporated within a simulated brick wall. The building panel  20  consists of a double-glazed unit  76  with a transparent area  22 , exterior and interior surface area patterns  23  and  33 , and opaque strip elements  24  that divide the transparent area  22  from the exterior and interior surface area patterns  23  and  33 . 
     The exterior surface area pattern  23  consists of rectangular opaque areas  43 , and between the rectangular opaque areas there are transparent margin areas  44 . The interior surface area pattern  33  typically consists of light and dark shade patterns  61 , wherein the light shade patterns face a building interior (not shown) and the dark shade patterns  61  face a glazing cavity. When viewed from the exterior, the two surface area patterns  23  and  33  create a three dimensional illusion of a brick wall with traditional mortar joints. At boundary areas between transparent areas  22  and surface area patterns  23  and  33 , there are opaque strip patterns  24 . Two opaque strip elements  24  are generally in register with each other. Typically, outwardly facing sides of the opaque strip elements  24  are of a light shade while inwardly facing sides of the strip elements are a dark shade with black being the preferred color. 
     FIG. 9 is an enlarged cross sectional detail of the double-glazed unit illustrated in FIG. 8 as seen on the line VIII—VIII. For interior glazing sheet  31 , various opaque and surface pattern areas are produced by first printing light shade patterns  89  onto a transparent adhesive plastic film sheet  90 . A second transparent adhesive film sheet  91  is laminated onto the first film sheet  90  with dark shade patterns  92  being printed where appropriate in register with the light shade patterns  89 , such that a double layer plastic film sheet is provided. This double layer plastic film sheet is then laminated onto a cavity face of the interior glazing sheet  31 . 
     For exterior glazing sheet  30 , various light shade surface patterns  93  are first printed on a transparent adhesive film sheet  94 . A second film sheet  95  is laminated onto the first film sheet  94  with dark shade patterns  96  being printed where appropriate in register with the light shade patterns  93  such that a double layer plastic film sheet  98  is provided. This double layer plastic film sheet material  98  is then laminated onto the rigid exterior glazing sheet  30 . A pre-applied low-e coating  97  may be incorporated on a cavity surface of the second film sheet  95 . 
     The preferred material for the plastic film sheets is polyethylene terephthalate (PET), and the preferred material for the adhesive is an optically clear, pressure sensitive acrylic adhesive. Various printed patterns are typically produced using pigmented ink and large format ink jet printers. 
     To prevent color fading, the plastic film sheet adjacent to the exterior glazing sheet  30  incorporates UV-absorbing material. As a further measure to prevent color fading, a glazing cavity can be filled with argon gas and a perimeter edge-seal can incorporate oxygen-scavenging material to remove all oxygen from the glazing cavity. 
     Instead of laminating printed plastic film sheets onto glazing cavity surfaces, decorative opaque and patterned areas can be produced through various other methods. For example, decorative patterns can be printed on a flexible plastic film that is suspended within the glazing cavity. Alternatively, one or more of the glazing sheets can incorporate a plastic polyester coating on a cavity glazing face. Decorative patterns can also be printed on paper and then transferred to the glazing sheet through a dye sublimation process. 
     A further alternative option is to create decorative patterns from strips or rolls of plastic sheet material that are adhered to the glazing sheets with pre-applied pressure sensitive adhesive. These strips can be fabricated from plastic sheet material that features a light shade on one side and a dark shade on another side. 
     FIG. 10 is a perspective view of an architectural building panel that is similar in construction to the building panel shown in FIG. 8 except that opaque strip elements  24  that surround transparent area  22  are hollow linear profiles that are adhered to glazing sheets  30  and  31  with pressure sensitive adhesive.