Abstract:
A double-pane window having a light-control assembly within its peripheral frame. The light-control assembly has an upper section which is adapted to redirect light entering the window through the outside pane so that the light, exiting the window through the inside pane, is reflected upwardly against a ceiling surface of the interior of a room, on the wall of which the window is mounted; and a lower section which is adapted to inhibit light entering the window through the outside pane from exiting the window through the inside pane. The lower section and optionally the upper section can each comprise a plurality of laterally-extending slats which can be pivoted about their laterally-extending axes to inhibit or redirect light entering the window. If desired, the slats of the lower section can be pivoted independently of the slats of the upper section. The slats of at least the upper section preferably have a transverse cross-section with a concave surface facing upwardly. It is also advantageous that the upper surface of these slats be highly reflective, and these slats can also be perforated or partially translucent.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. utility application Ser. No. 09/141,494, filed Aug. 27, 1998 (the &#39;494 application), now U.S. Pat. No. 6,123,137, issued Sep. 26, 2000. The &#39;494 application corresponds to and claims priority to European Application No. 97202627.2, filed Aug. 28, 1997. The &#39;494 application and the corresponding European application are hereby incorporated by reference as though fully set forth herein. 
    
    
     BACKGROUND OF THE INVENTION 
     a. Field of the Invention 
     This invention relates to a multiple-glazed window containing an integral assembly for controlling the amount of daylight passing though the window into a room. In particular, the invention relates to a window having a peripheral frame enclosing inside and outside glass panes that are substantially parallel and define a space between them which is preferably sealed and in which the light-control assembly is mounted. 
     b. Background Art 
     Double-pane windows containing motorized venetian blinds as light-control assemblies have been described in U.S. Pat. Nos. 4,723,586 and 4,979,552. Such windows have satisfied most light-control requirements. In addition, the mere positioning of a venetian blind within the space between two glass panes in a window has long been known to reduce heat losses by radiation through the window to an extent approaching those of windows with triple panes. 
     Notwithstanding this, the increased use of computer monitors in office buildings has presented additional demands on windows and their associated light-control assemblies for providing protection against the glare from sunlight, without totally eliminating daylight illumination within such buildings. Blocking such glare by closing the window blinds has often diminished the level of illumination in offices below acceptable limits, but increasing the use of artificial illumination, such as electric lighting, has also been objectionable from an environmental point of view. 
     Anti-glare venetian blinds have also been previously described. For example, in European patent 0,303,107, an anti-glare venetian blind is provided with slats: which are upwardly concave, which have their inner longitudinal edges (facing towards the room) as high or higher than their outer longitudinal edges (facing away from the room), which are mirrored on at least their topsides and retro-reflecting on their undersides, and the spacing and position of which are so selected that the light passes through them mostly into an angular region above the horizon. In European patent application 0,606,543, an anti-glare blind is provided with slats which are: upwardly concave, mirrored on their topsides and at least partially perforated. Although these blinds appear to be able to guide light towards the ceiling of a room and avoid glare, they are not adapted to allow some sunlight to enter the rest of a room. In this regard, it would be desirable, on sunny days, to be able to block or inhibit heat and glare from entering the rest of the room, without blocking daylight illumination entirely from the rest of the room. 
     BRIEF SUMMARY OF THE INVENTION 
     For this reason, there has been a continuing interest in eliminating glare and sunlight from the lower portions of office windows while redirecting light from the upper portions of office windows within offices. It is therefore an object of this invention to provide an improved multiple-glazed window with an integral light-control assembly. 
     In accordance with this invention, a double-pane window is provided, containing, within a peripheral frame, a light-control assembly that includes: 
     i) an upper section which is adapted to redirect light entering the window through the outside pane so that the light exits the window through the inside pane; and 
     ii) a lower section which is adapted to reduce or eliminate light entering the window through the outside pane from exiting the window through the inside pane. Preferably, the light passing through the upper section of the window can be reflected upwardly, against a ceiling surface of the interior of a room, to provide additional illumination. In the lower section of the window, sunlight and glare from the outside, which might otherwise disturb the occupants of the room, can be substantially reduced or eliminated as desired without losing altogether the benefits of daylight illumination. 
     Advantageously the upper and lower sections each comprise a venetian blind assembly provided with a plurality of substantially parallel laterally-extending elongate slats, the slats of at least the lower section being pivotable about their laterally-extending axes. Such an assembly allows the use of standard components from existing double-pane windows containing enclosed venetian blinds such as are disclosed in U.S. Pat. No. 4,723,586. 
     Desirably, the lower section of the light-control assembly is adjustable independently of the upper section. This permits the assembly to be used to optimize light control under different conditions. 
     The slats of at least the upper section of the light-control assembly preferably have a highly reflective upper surface for improved control of daylight which these slats redirect through the window. For the same purpose and advantageously in combination therewith, the slats of at least the upper section can be perforated or partly translucent. 
     Further enhancement of light distribution with the window of the invention can be obtained by giving the slats of the upper section a cross-section, as taken transversely (i.e., from the outside to the inside of the window), that includes a concave surface facing upwardly. In certain embodiments of the invention, each of the upwardly concave slats of the upper section preferably has a mirrored top surface and a retro-reflective bottom surface. In other embodiments, the upwardly concave slats of the upper section preferably have a mirrored top surface and are wholly or partially perforated. 
     In addition, heat losses by radiation through the window of this invention, particularly in the winter, can be further substantially reduced by providing the surface on the inside- and/or outside-facing surfaces of preferably all of the slats with an emission coefficient lower than 0.5, and preferably lower than 0.3, for radiation with a wavelength larger than 1.5 micrometer. In this regard, advantageous are aluminium slats coated with a very thin zinc chromate layer, such as are described in British patent 1,536,600. 
     Although each slat of the light-control assembly in accordance with this invention can be individually suspended from pivots on laterally opposite sides of the window frame, it is preferred that the slats be tiltably suspended from laterally-spaced tilt cords. In this regard, the slats of the lower section of the light control assembly may be tiltably suspended from laterally-spaced tilt cords and the slats of the upper section be non-tiltably fixed in a position re-directing light upwardly towards the ceiling of the room. 
     Preferably an electric motor is used to adjust at least the slats of the lower section of the light-control assembly. A suitable electric motor is described in U.S. Pat. No. 4,979,552 and is preferably hermetically sealed in the space between the windowpanes. The use of such an electric motor is particularly advantageous when movement of the light-control assembly is to be adjusted with a microprocessor control so as to allow optimal light regulation under varying conditions without requiring the intervention of the room occupants. 
     In one embodiment of this invention, the top of the lower section is suspended from a laterally-extending intermediate bar, beneath the upper section. Such an arrangement allows an increased number of existing components of known double-pane windows containing venetian blinds to be used and also allows the upper and lower sections to be mounted in the window in essentially the same manner. Advantageously, the intermediate bar is suspended only at its lateral edges from laterally opposite sides of the frame, using a T-shaped connector at one lateral edge and an electric motor for the lower section as a connector at the other lateral edge. 
     The window of the invention is substantially vertical. Normally it will be truly vertical but it may be mounted in a slanted position in which case the plane of its light-control assembly is advantageously positioned closer to the upper glass pane of the window, as so mounted. In this regard, it is especially advantageous that the attachment of the upper and lower sections of the light-control assembly to the intermediate bar be positioned closer to the upper glass pane to compensate for any sagging of the light-control assembly within the slanted window, and it is particularly advantageous that the upper end of the upper section and the lower end of the lower section also be positioned closer to the upper glass pane to compensate for any sagging of the light-control assembly within the slanted window. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the sealed double-pane window with a light-control assembly of this invention will now be described in more detail with reference to the accompanying drawings in which: 
     FIG. 1 is a schematic perspective view of a double-glazed window, shown partly in section, containing a light-control assembly according to the invention; 
     FIG. 1A is an enlarged view of a length of a slat from the upper section according to one alternative embodiment; 
     FIG. 2 is a vertical sectional view of the window of FIG. 1, showing in more detail the light-control assembly and its mounting within the window; 
     FIG. 3 is a front elevation view showing an assembled peripheral frame for the window of FIG. 2 prior to fitting the light-control assembly within the frame; 
     FIG. 4 is a transverse cross-sectional view, taken along line IV—IV in FIG. 3, showing one embodiment of the intermediate bar of the light-control assembly; and 
     FIG. 5 is partial vertical cross-sectional view, of an alternative embodiment of the window of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Schematically shown in FIGS. 1 and 2 is one embodiment of a substantially vertical, hermetically sealed, double-pane window of this invention, generally indicated by reference A. The window A is provided with a light-control assembly, generally indicated by reference B, that is mounted in the space between the two glass panes  1  and  3  of the window. The first or outside pane of glass  1  and the second or inside pane of glass  3  are positioned on opposite sides of a rectangular peripheral, plastic or metal (e.g., aluminum) frame  5  of the window A. 
     The glass panes  1  and  3  and the frame  5  are adhered together by a suitable sealing compound, such as is conventional in making hermetically sealed, multiple-glazed windows. 
     The light-control assembly B, mounted between the glass panes  1  and  3  and within the frame  5  of the window A of FIGS. 1 and 2, has an upper section  7  and a lower section  9 . Each section  7  and  9  comprises an array of parallel elongate slats  11  and  13  respectively, that are substantially horizontal and laterally-extending and can be pivoted or tilted about their laterally-extending axes. In alternative embodiments of the assembly B, the slats  13  of the lower section  9  can be pivoted or tilted about their laterally-extending axes while the slats  11  of the upper section are non-tiltably fixed in a position allowing the light to be guided towards the ceiling. Preferably, the upper section  7  occupies less of the area of the window A than does the lower section  9 . 
     The slats  11  and  13  each have a curved cross-section when viewed parallel to the panes of the window A. The slats  11  in the upper section  7  have their concave surfaces facing generally upwardly, and the slats  13  in the lower section  9  have their convex surfaces facing generally upwardly. Each section  7  and  9  of the light-control assembly B is provided with its own motor drive  15  and  17 , respectively, for tilting its slats. Of course, if the slats  11  of the upper section  7  are non-tiltably installed in the window, its motor drive  15  can be omitted. 
     The first motor  15  for tilting the slats  11  of the upper section  7  is mounted in the peripheral frame  5  as described in U.S. Pat. No. 4,979,552. 
     The second motor  17  for tilting the slats  13  of the lower section  9  is connected to a lateral edge of a substantially horizontal laterally-extending elongate intermediate bar  19  which separates the upper section  7  from the lower section  9  of the light-control assembly B of the double-pane window A. 
     The use of separate motors  15  and  17 , together with a suitable control for activating the motors individually, permits the slats  11  and  13  of the upper and lower sections to be tilted separately and independently. The use of a microprocessor as a control for the motors would permit the slats of the light-control assembly B to pivot automatically in response to changing light conditions in the room(s), in the walls of which the window is mounted, or in response to other parameters, such as time. 
     As a result of this arrangement, daylight can be reflected from the outside by the slats  11  of the upper section  7  of the window A on to a ceiling surface of a room to compensate for the light blocked out, for glare protection, by the slats  13  of the lower section  9  of the window. 
     A suitable proportion of light protection and light redirection can be obtained for many windows of office buildings and the like if the upper section  7  extends over roughly one-third of the height of the window A as indicated by “a” in FIG.  2  and the lower section  9  extends over roughly two-thirds thereof as indicated by “b” in FIG.  2 . 
     The light distribution effects of the upper section  7  of the light-control assembly B can be further improved by positioning its slats  11  with their upwardly concave surfaces  21  facing general vertically upward and additionally by providing these concave surfaces  21 , with highly reflective properties. In this regard, top surfaces of these slats can be mirrored as described in EP 0,303,107. The bottom surfaces of these slats  11  can likewise be provided with retro-reflective properties as described in EP 0,303,107 or instead, the slats  11  can be wholly or partially perforated as described in EP 0,606,543 and shown in FIG.  1 A. 
     As seen in FIG. 2, the upper ends of both the upper and lower blind sections  7  and  9  of the light-control assembly B of this invention are pivotally suspended from respective transversely-extending tilt bars  23  and  25  by means of parallel ladder strings  27 , the upper ends of which are attached to the transverse edges of the tilt bars. The lower end of each blind section  7  and  9  carries a transversely-extending terminal slat  29  and  30  respectively, which preferably is identical to the upper tilt bars  23  and  25 . The lower ends of the parallel ladder strings  27  are attached to the transverse edges of the terminal slats  29  and  30 . The upper tilt bar  23  and the lower terminal slat  30  are pivotally connected to conventional, horizontali upper and lower carriers or glass spacers  31  and  32  respectively, which are mounted within the frame  5 , on its top and bottom respectively. The lower tilt bar  25  and the upper terminal slat  29  are pivotally connected to the bottom and top of the intermediate bar  19 . 
     The tilt bars  23  and  25  and terminal slats  29  and  30  can be pivotally connected to their respective spacers  31  and  32  and intermediate bar  19  in a conventional manner. Preferably, these elements are connected in the manner described in U.S. Pat. No. 4,723,586, using detent grooves (not shown) in the top and bottom of the spacers  31  and  32  and the intermediate bar  19  and using hanger pivots  33  mounted in the grooves and pivotally connected to the respective tilt bars and terminal slats. 
     The transverse spacing “c” in FIG. 2 between the panes of glass  1  and  3  is a function of the thickness of the peripheral frame  5 , including its spacers  31  and  32 . The transverse spacing “c” must accommodate the transverse thickness “d” of the blind slats  11  and  13  and the transverse thickness of the spacers  31  and  32  as shown in FIG.  2 . In sealed glass blind units as described in U.S. Pat. No. 4,979,552, it is not uncommon for such spacers to have a transverse width of only about 22 millimeters and for the blind slats to have a transverse width of only about 12 to 16 millimeters. 
     With such reduced dimensions of the slats  11  and  13  in accordance with this invention, as compared to the dimensions of conventional venetian blinds, the intermediate bar  19  should be as unobtrusive as possible, and its height “e” as shown in FIG. 2 should be about the same as the vertical spacing between adjacent slats  11  and  13 . At the same time, the intermediate bar  19  should be sturdy enough to carry the weight of the bottom section  9  of the light control assembly B. 
     If desired, the transverse edges of the intermediate bar  19  can be mounted on the opposed inner surfaces of the glass panes  1  and  3  in a manner similar to that used for mounting the spacers  31  and  32  on the frame  5 . The sealing compound used to bond and seal the frame  5  and glass panes  1  and  3  together could also be used for this purpose. However, it is possible that the intermediate bar  19  to be free of attachment to the inner surfaces of the glass panes  1  and  3 , and, in particular, for the intermediate bar  19  to be free-floating relative to the panes  1  and  3 . Alternatively, the intermediate bar  19  could be suspended from the terminal slat  29  of the upper section  7  of the light control assembly B, and if desired, the motor  17  for driving the slats  13  of the lower section  9  could also be free-hanging with the intermediate bar  19  within the window A of this invention. 
     However, it is preferred to suspend the intermediate bar  19 , as shown schematically in FIG. 3, from laterally opposite sides of the frame  5  so as not to put too much strain on the ladder cords  27  or tilt cords (not shown) or on the supporting components of the upper section  7  of the light control assembly B. To this end, laterally opposite sides of the frame  5  are provided with vertical frame members  35 ,  37 ,  39  and  41 , two of the frame members  35  and  37  being located above the intermediate bar  19 , the other two frame members  39  and  41  being located below the intermediate bar  19 , and an upper frame member  35  and a lower frame member  39  being located on opposite lateral sides of the frame from the other upper and lower frame members  37  and  41  respectively. The motor  15  for the upper section  7  of the light-control assembly B is connected to both the upper spacer  31  and the top of the left upper vertical frame member  35 , thereby forming the left upper corner of the frame. The other motor  17  for the lower section  9  of the light-control assembly B is connected to the bottom of the left upper vertical frame member  35 , as well as to the top of the lower left vertical frame member  39 . The remaining three corners of the frame are connected by L-shaped comer connectors  43 . 
     The intermediate bar  19  is connected to the right upper and lower frame members  37  and  41  by a T-shaped connector  45  which is separately shown to an enlarged scale in an insert to FIG.  3 . The T-shaped connector is adapted to be inserted into the bottom of the upper frame member  37 , into the top of the lower frame member  41  and into a lateral side of the intermediate bar  19 . 
     As shown in FIG. 3, the motors  15  and  17  each have a laterally-protruding, slotted shaft  47 . Each of these shafts  47  is adapted to engage a lateral edge of one of the tilt bars  23  and  25  of the upper and lower sections  7  and  9  of the light-control assembly B of the window A of this invention as shown in FIG.  2 . As described in U.S. Pat. No. 4,979,552, electrical conduits (not shown) pass through the frame, preferably in a sealed manner, and are connected to the motors  15  and  17  to power them. 
     A cross-section of the intermediate bar  19  is shown in FIG.  4 . Upwardly extending, hanger attachment flanges  49  and  51  define an undercut detent groove between them on the upper side of the intermediate bar  19 . Similar detent grooves are also provided between the downwardly extending, hanger attachment flanges  53  and  55  on the lower side of the intermediate bar  19 . The pivot hangers  33 , such as are described in U.S. Pat. No. 4,723,586, are engaged in such grooves and are connected to the tilt bars  23  and  25  and the terminal slats  29  and  30 . 
     If a double-pane window A as shown in FIGS. 1-4 were to be mounted in an inclined position, as is sometimes required from an architectural point of view, there would be a tendency for its slats  11  and  13  to hang against the lower pane of glass. 
     Such an arrangement is shown in FIG.  5 . 
     In the following description, corresponding parts of the alternative embodiment of the invention shown in FIG. 5 are referred to by reference numerals which differ by “ 100 ” from those of the embodiment shown in FIGS. 1-4. 
     FIG. 5 shows an inclined sealed double-pane window, generally A′, with a light-control assembly B′ of this invention having a modified intermediate bar  119 . 
     In the window A′ of FIG. 5, the tendency for the slats  111  and  113  to sag and, as a result, to hang against the lower pane  103  of glass is compensated for by displacing the hanger attachment flanges  149 ,  151 ,  153  and  155  on the top and bottom of the intermediate bar  119  toward the upper pane  101 . This results in there being unequal distances “f” and “g” in FIG. 5 between i) the pivot points of the blind sections  107  and  109  with the intermediate bar  119  and ii) the panes  101  and  103 . Preferably, the hangers (not shown in FIG. 5) on the tilt bar (also not shown in FIG. 5) at the upper end of the upper section  107  and on the terminal slat (also not shown in FIG. 5) at the lower end of the lower section  109  also are mounted on their respective upper and lower spacers closer to the upper glass pane  101  to compensate further for any sagging of the light-control assembly B′within the slanted window A′. However, the transverse spacing “h” in FIG. 5 of the intermediate bar  119  from the upper and lower panes  101  and  103  is preferably kept equal, so that the intermediate bar can be connected to the vertical frame members (not shown) in the same manner as is described in relation to FIG.  3 . 
     This invention is, of course, not limited to the above-described embodiments of FIGS. 1-5, which may be modified without departing from the scope of the invention or sacrificing all of its advantages. In this regard, the terms in the foregoing description, such as “left”, “right”, “lateral”, “bottom”, “top”, “transverse”, “upper”and “lower”, have been used only as relative terms to describe the relationships of the various elements of the combined multiple-glazed window and light-control assembly of the invention.