Abstract:
A window design that includes a thin semi-transparent reflective surface that is intentionally distorted, so as to disrupt and confuse reflected images without significantly impairing transmitted viewing, thereby providing energy-efficient properties while reducing inadvertent collisions, particularly from birds. The surface can be a layer of material suspended or supported between two panes of a window or sliding glass door, or can be a coating on a pane.

Description:
BACKGROUND AND SUMMARY  
       [0001]     Embodiments relate to windows for edifices, such as houses and office buildings. More particularly, embodiments relate to windows incorporating arrangements to reduce the likelihood of birds flying into and colliding with windows. Additionally, embodiments relate to windows incorporating arrangements to reduce thermal load on a structure.  
         [0002]     In order to improve the energy efficiency of traditional glass windows, a semi-transparent, semi-reflective coating, or tinting can be incorporated, which significantly improves the thermal insulating properties. However, that arrangement exacerbates the already serious problem of bird collisions, which unintentionally cause millions of unnatural deaths and injuries every year, which is a serious concern to many people.  
         [0003]     Embodiments thus contemplate an arrangement of glass and/or plastic and a semi-reflective material arranged to reduce the likelihood of a bird colliding with a window using embodiments while still reducing thermal load on the structure in which such a window is installed. In embodiments, a window includes at least one layer of semi-reflective material, such as Mylar® or acetate with a metallized coating, imbued with a distortion. The layer can be hung between and/or adjacent window panes, can be a coating on one or more of the panes, or can be a shade or drape mounted in, on, or adjacent the window. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0004]     Embodiments will be described with reference to the accompanying Figures.  
         [0005]      FIG. 1  is a schematic front view of a picture window incorporating an embodiment of the invention.  
         [0006]      FIG. 2  is a cross section of the window of  FIG. 1  taken along the line  2 - 2 .  
         [0007]      FIGS. 3 and 4  show an alternate implementation of the window of  FIGS. 1 and 2  in which the semi-reflective layer can be moved.  
         [0008]      FIG. 5  is a schematic front view of a window incorporating an embodiment of the invention using a different distortion.  
         [0009]      FIG. 6  is a schematic cross section of an alternate implementation of the window of  FIGS. 1-4  in which an alternate distortion induction method is used. 
     
    
     DETAILED DESCRIPTION  
       [0010]     The description that follows and the accompanying FIGS. deal with a picture window, but many other types of windows can use embodiments, including, but not limited to, casement windows, double-hung windows, sliding glass doors, French doors and windows, and louvered windows. Further, while the description and FIGS. deal with double pane windows, triple and other multi-pane windows can employ embodiments, and even single pane windows can employ aspects of embodiments.  
         [0011]     Beginning with  FIGS. 1 and 2 , embodiments are employed in a window  10  with a frame  11  and a casing  12 , and preferably including at least two panes  13 ,  14 . The panes are preferably glass, but can be plastic or any other suitable material. Further, not all of the panes need be of the same material(s). Embodiments incorporate a semi-reflective material  15 , such as metallic coated Mylar® or acetate, that is imbued with a distortion so as to confuse the apparent reflected image, while leaving the transmission characteristics essentially unaffected. For example, the material  15  can be intentionally distorted, warped, or embossed, or otherwise imbued with an image confusing distortion or the like. Preferably, the material  15  takes the form of a thin layer of material hung between the panes  13 ,  14  or applied to one of the panes  13 ,  14 . When employed in the typical situation where external illumination is significantly greater than inside ambient light level, outward viewing is transmission dominated, while the view from the exterior would seem mostly reflective. Confounding or confusing the reflected image breaks up any natural scene that might be seen from an exterior of a building in which the window  10  is installed, which can prevent wildlife from inadvertently interpreting the window as an open passage. Embodiments could also be useful in architectural situations where intense non-diffused reflections are undesirable, or in such applications as “one-way” security mirrors.  
         [0012]     A particular example according to embodiments, as seen in  FIGS. 2-4 , includes the semi-reflective material  15  in the form of a membrane or film suspended between two separated window panes  13 ,  14 , effectively forming a triple glazing. Standard glass panes can be mounted in the frame  11  or the casing  12  about, for example,  20  millimeters apart, while the material  15  can be hung between the two panes  13 ,  14  or otherwise attached to the casing  12  between the two panes.  
         [0013]     With regard to the coating, deposition of a material, such as chrome or silver, on some optically desirable material, such as a glass pane or a plastic film like Mylars, acetate, or the like, would likely be appropriate. Thinner films or materials will likely work better and should preferably provide about equal transmission and reflection; some absorption loss may occur, likely on the order of about 30%. Multi-layer coatings are also contemplated in embodiments inasmuch as they can be more efficient and can offer colored films. Additionally, chemical treatments of the optical material, as well as sprayed on coatings, might be used.  
         [0014]     To achieve the desired reflection confusing or altering effect, the material  15  is imbued with a distortion  16 , such as a wavy distortion. One way to effect the distortion  16  is to treat the material  15  so that is has a “natural” set or warping that causes it to hold a wavy surface when suspended. For example, embossing, crinkling, or otherwise imposing a shape memory into the material  15 . Alternatively, the material can be wrapped over a plurality of rods  60  or the like, such as dowel pins, along the sides of the frame, as seen, for example, in  FIG. 6 . For example, 10 mm diameter dowel pins can be arranged on 20 mm centers to create membrane waves with a 40 mm period and 10 mm amplitude, which would tend to appear like a series of odd-looking horizontal bars. Additional embodiments can employ a warped pattern embossed in the film to distort the reflected imagery, where various patterns or textures or diffusive characteristics could be offered.  
         [0015]     The particular pattern or distortion used can vary as desired and will have an aesthetic variable in the decision. “Wavy lines” are easy to implement and suffice, but a circular pattern or distortion, such as that shown in  FIG. 5 , may be preferred by others, and other, more intricate patterns or distortions could be used, too.  
         [0016]     In embodiments, it is also advantageous to tint the internal transparent window pane. Such tinting can reduce the reflective properties of the glass when viewing from inside outward, since reflected light would have to pass through the attenuating tint twice, compared to once for the transmitted light, thereby effectively reducing the reflective appearance. Other typical anti-reflection methods can also be employed, such as a circular-polarizing anti-reflection film, which would nearly eliminate the inside reflective component. Additionally, standard anti-reflection coatings on the flat glass surfaces can also reduce the unwanted specular reflections from treated flat transparent surfaces, although the warped semi-reflective component would tend to overwhelm such reflections. Such circular-polarizing and other anti-reflective films and/or coatings can be had from many vendors, such as American Polarizers, Inc., of Reading, Pa.  
         [0017]     Alternative embodiments can employ the semi-reflective plastic film as a window shade, such as Roman blinds, a zigzag or fan-fold form, or a wavy form like ribbon candy pierced by cords, which could be retractable like typical accessory shades for standard windows. In such embodiments, a typical roll shade would also be possible, if the material is made to automatically assume a non-flat profile. An example of an embodiment employing a folding film is seen in  FIGS. 4 and 5 . The reflection disruptive material  15  is affixed at its top edge to the casing  12  or frame  11 . A folding system  30  includes a line  31  extending from the exterior of the window  10  over a pulley  32  through the material  15  to a batten  33 . The batten  33  in the bottom edge of the material to serves as a downward biasing element as well as an attachment point for the line  31 . By pulling the line  31 , the batten  33  rises, folding the material  15  up out of the way—substantially out of interposition between the panes  13 ,  14  as seen in  FIG. 5 .  
         [0018]     Embodiments could further use a distorting semi-reflective surface embedded within a glass or plastic window pane, or even a composite structure such as safety glass. With the external surfaces flat and the index of refraction constant, the transmitted imaging would be optically faithful, while reflection off the embedded layer would be intentionally confused. Such an embedded layer could be achieved, for example, by forming one of the panes  13 ,  14  as a composite pane having end portions and the middle embedded layer. The end portions would each have a planar surface and complementary wavy surfaces. One of the wavy surfaces would support the embedded layer, as by static, gluing, coating, or the like. The other wavy surface would then be affixed, yielding a composite pane with two planar surfaces and a semi-reflective embedded layer.  
         [0019]     The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.