Abstract:
The embodiments disclosed herein relate to light shelves for daylighting, and more particularly to light shelves that include both a diffuser and a reflector. According to aspects illustrated herein, there is provided a light shelf that includes at least one anchor bracket suitable for attachment to a building structure; at least one support beam attached to the anchor bracket; and a plurality of light transmitting airfoil-shaped louvers each supported and positioned by the support beam at a preselected fixed profile angle, wherein each of the louvers includes a diffuser and a reflective surface.

Description:
BACKGROUND 
     Natural solar light, i.e., sunlight, is a very desirable light source for interior use. Daylighting is the method of lighting a building&#39;s interior with full-spectrum, sunlight which supplements or replaces electric lighting during the daytime. There are many benefits to using daylight for illuminating areas within enclosed structures such as buildings. The use of daylight over artificial illumination for interior illumination provides a more balanced color rendering of objects which is more aesthetically pleasant and also reduces the need for energy to illuminate the interior of the building artificially. An additional benefit is the reduced amount of radiant energy produced by artificial illumination sources which can, in turn, reduce the amount of cooling needed to maintain a comfortable temperature within a building. 
     A problem that is frequently encountered when an area is illuminated using artificial light sources or natural daylight is how to spread the light adequately and evenly. Simple diffusers in the form of a sheet of translucent material can be used to spread light but, although they are inexpensive, they do not transmit light efficiently and are also unable to direct light in a controlled manner to where it is needed. Interior light shelves are often used on the inside of buildings to block sunlight into a building space and “bounce” the sunlight upward and deeper into the interior space. The light shelves are attached to the interiors of the buildings and extend outward away from the buildings facade. Artificial light shelves have been proven to reduce requirements for perimeter artificial lighting, thereby conserving electrical energy costs. In many cases, architects are designing curtain wall systems where light shelves are directly integrated into the structural members of the curtain wall. 
     SUMMARY OF THE DISCLOSURE 
     There is provided in one aspect a light transmitting louver that includes a louver wherein: a first curved element of the louver has a first end and a second end, wherein the first curved element is composed of a plastic or metal; a second element of the louver has a first end and a second end, wherein the first end of the second element connects with the second end of the first curved element, and wherein the second element includes a diffuser; and a third curved element of the louver has a first end and a second end, wherein the second end of the second element connects with the first end of the third curved element, and wherein the third curved element includes a reflective surface, wherein the first curved element, the second element, and the third curved element connect such that the louver forms an airfoil-shaped body. 
     In an embodiment, the first end of the first curved element and the second end of the third curved element do not meet, resulting in an opening in the airfoil-shaped body which allows for the channeling of light to the diffuser of the second element. 
     In another aspect, the present invention provides a light transmitting louver that includes a louver wherein: a first curved element of the louver has a first end and a second end, wherein the first curved element is composed of a plastic or metal, and wherein at least a portion of a surface of the first curved element includes a reflective surface; and a second curved element of the louver has a first end and a second end, wherein the first end of the second curved element connects with the second end of the first curved element, and wherein the second curved element includes a diffuser; wherein the first curved element and the second curved element connect such that the louver forms an airfoil-shaped body. 
     In an embodiment, the first end of the first curved element and the second end of the second curved element do not meet, resulting in an opening in the airfoil-shaped body which allows for the channeling of light to the reflective surface of the first curved element. 
     In still another aspect of the present invention, there is provided a light shelf that includes at least one anchor bracket suitable for attachment to a building structure; at least one support beam attached to the anchor bracket; and a plurality of light transmitting airfoil-shaped louvers each supported and positioned by the support beam at a preselected fixed profile angle, wherein each of the louvers includes a diffuser and a reflective surface. 
     In an embodiment, the light transmitting airfoil-shaped louvers of the light shelf include a first curved element having a first end and a second end, wherein the first curved element is composed of a plastic or metal; a second element having a first end and a second end, wherein the first end of the second element connects with the second end of the first curved element, and wherein the second element includes the diffuser lens; and a third curved element having a first end and a second end, wherein the second end of the second element connects with the first end of the third curved element, and wherein the third curved element includes the reflective surface. 
     In another embodiment, the light transmitting airfoil-shaped louvers of the light shelf include a first curved element having a first end and a second end, wherein the first curved element is composed of a plastic or metal, and wherein at least a portion of a surface of the first curved element includes the reflective surface; and a second curved element having a first end and a second end, wherein the first end of the second curved element connects with the second end of the first curved element, and wherein the second element includes the diffuser. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The presently disclosed embodiments will be further explained with reference to the attached drawings, wherein like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the presently disclosed embodiments. 
         FIG. 1  depicts a side view of an illustrative embodiment of a light transmitting louver of the present invention. 
         FIG. 2  depicts a side view of an illustrative embodiment of a light transmitting louver of the present invention. 
         FIG. 3  depicts a perspective view of an illustrative embodiment of a light shelf of the present invention having a plurality of the light transmitting louvers of  FIG. 1 . 
         FIG. 4  depicts a perspective view of an illustrative embodiment of a light shelf of the present invention having a plurality of the light transmitting louvers of  FIG. 2 . 
         FIGS. 5A and 5B  show the light shelf of  FIG. 3  integrated into structural members of a curtain wall.  FIG. 5A  is a floor plan view of the light shelf.  FIG. 5B  is a cross-sectional view of the light shelf taken along line A-A of  FIG. 5A . 
         FIGS. 6A and 6B  show the light shelf of  FIG. 4  integrated into structural members of a curtain wall.  FIG. 6A  is a floor plan view of the light shelf.  FIG. 6B  is a cross-sectional view of the light shelf taken along line B-B of  FIG. 6A . 
         FIG. 7  depicts a side view of an illustrative embodiment of an end cap of the present invention for use with a light transmitting louver of the present invention. 
         FIG. 8  depicts a side view of the light transmitting louver of  FIG. 2  having the end cap of  FIG. 7 . 
     
    
    
     While the above-identified drawings set forth presently disclosed embodiments, other embodiments are also contemplated, as noted in the discussion. This disclosure presents illustrative embodiments by way of representation and not limitation. 
     DETAILED DESCRIPTION 
     The present invention is now discussed in more detail referring to the drawings that accompany the present application. In the accompanying drawings, like and/or corresponding elements are referred to by like reference numbers. 
     Light shelves provide the advantage of shifting light from a window so that the light comes from a more overhead direction, improving the quality of illumination. Light shelves require direct sunlight, and provide useful daylighting of a zone that lies along the exterior wall. The width of this zone depends on the height of the top of the window, the orientation of the window, the latitude of the site, the time of day, and the clarity of the sky. The width of the zone varies with sunlight conditions. With typical clear windows, for example, the zone may extend inward a distance of about 10 feet to about 20 feet. The light penetration may be deeper if the window is very tall. 
     Windows that face the sun receive energy that could be useful for daylighting. In principle, if a window faces anywhere between southeast and southwest and if the window receives direct sunlight, each unit of window area could illuminate 20 to 100 units of interior area. However, this is possible only if the sunlight can be distributed efficiently. The challenges of distributing this free lighting energy are lighting geometry and glare. In order for illumination to be useful, illumination must come from overhead. Raw sunlight coming through a window falls on the floor, so some method is needed to redirect the sunlight so that the sunlight comes from overhead. 
     Many concepts have arisen for taming the sunlight that enters through windows. A typical prior art light shelf is essentially a mirror that is installed inside a window, facing upward. The mirror reflects incoming sunlight toward the ceiling. The reflection is controlled by the law of optics that says the angle of reflection equals the angle of incidence. The ceiling then distributes the light into the working areas of the space. If the sun is low in the sky, sunlight penetrates deeply into the space. If however, the sun is high, the ceiling is illuminated close to the wall. 
     Pure specular reflection creates a sharply defined rectangular bright spot on the ceiling. You can reduce this effect by making the reflecting surface of the light shelf more diffuse. This spreads out the light on the ceiling. However, it also concentrates the ceiling illumination close to the light shelf. If the reflection is very diffuse, penetration into the space is sacrificed. 
     As used herein, the term “daylighting” refers to applications in which natural daylight is allowed into buildings or other structures (such as vessels or aircraft) through openings provided with means by which the amount of usable light entering through the opening is enhanced by various means. This may be achieved, for example, by diverting light from incident angles at which they would not otherwise provide useful light within the building or other structure, or by capturing light passing the opening which would not otherwise enter the building through it. 
     As used herein, the term “diffuser” refers to a medium that scatters light. In an embodiment, the light is scattered evenly. 
     As used herein, the term “reflective surface” refers to a surface that reflects or shifts light. 
     As used herein, the term “light transmitting louver” refers to a louver of the present invention having a diffuser for scattering sunlight, and a reflector for shifting sunlight. 
     As used herein, the term “airfoil-shaped body” refers to the shape of a louver of the present invention as seen in cross-section. The airfoil-shape resembles the cross-section of a wing. 
     As used herein, the term “channeling of light” refers to the redirection of light (e.g., sunlight) to the inside of a space. The channeling of light provides a better distribution of light into a room (e.g., for task lighting or ambient lighting). 
     As used herein, the term “curtain wall” refers to a building facade, typically spanning multiple floors, which does not carry any dead load from the building other than its own dead load. 
       FIG. 1  is a side view of an illustrative embodiment of a light transmitting louver  10  of the present invention. The light transmitting louver  10  includes a first structural element  12 , a second element  14 , and a third element  16 . The first element  12  and the third element  16  connect with the second element  14 , such that the louver  10  forms an airfoil-shaped body, as viewed in cross-section. The first element  12  and the third element  16  are structural elements, and are fabricated from a plastic or metal material. The second element  14  has lips  13 , that are responsible for the connection of the second element  14  with both the first element  12  and the third element  16 . The lips  13  provide a means for the second element  14  to rest on the structural elements of the first element  12  and the third element  16 . The second element  14  essentially is held by gravity between the first element  12  and the third element  16 . In an embodiment, the second element  14  can be easily removed from the remaining elements of the louver  10  such that the second element  14  can be cleaned or replaced, for example, in the event that dust collects on top of the second element  14 . In an embodiment, fasteners can be used to attach the second element  14  to the first element  12  and the third element  16 . In an embodiment, the second element  14  includes a diffuser. In an embodiment, the second element  14  is composed of a diffuser. In an embodiment, the second element  14  is manufactured from a diffuser material, such as a diffuser lens that scatters light. An opening  17  is created in the airfoil-shaped body of the louver  10 . The opening  17  is created due to a first end  12   a  of the first element  12  not meeting up with a second end  16   b  of the third element  16 . The third element  16  includes a reflective material. In an embodiment, the third element  16  includes a reflective surface. In an embodiment, the third element  16  is composed of a reflective material. In an embodiment, the third element  16  is manufactured from a reflective material. In an embodiment, the third element  16  is manufactured from a plastic or metal material that further includes a surface having a reflective material. Connecting means  11  are used to connect the louver  10  to a structural element to create a light shelf. 
       FIG. 2  is a side view of an illustrative embodiment of a light transmitting louver  20  of the present invention. The light transmitting louver  20  includes a first structural element  22  and a second element  24 . The first element  22  connects with the second element  24  such that the louver  20  forms an airfoil-shaped body, as viewed in cross-section. The second element  24  has two lips  25 . One of the lips  25 , connects the second element  24  with the first element  22 , while the other lip  25  is capable of connecting with an end cap, as will be described in detail below. In an embodiment, the first element  22  and the second element  24  can be easily disassembled such that the various elements can be cleaned or replaced if needed. The first element  22  is a structural element, and is fabricated from a plastic or metal material. In an embodiment, at least a portion  23  of the first element  22  includes a reflective material. In an embodiment, the portion  23  is manufactured from a reflective material. In an embodiment, the portion  23  is composed of a reflective material. In an embodiment, the portion  23  is manufactured from a plastic or metal material that further includes a surface having a reflective material. The second element  24  is manufactured from a diffuser material, such as a diffuser lens that scatters light. An opening  27  is created in the airfoil-shaped body of the louver  20 . The opening  27  is created due to a first end  22   a  of the first element  22  not meeting up with a second end  24   b  of the second element  24 . Connecting means  21  are used to connect the louver  10  to a structural element to create a light shelf. 
     In an embodiment, the plastic material of the structural elements of the present invention are reinforced with fiberglass. In an embodiment, the metal material of the structural elements of the present invention are an aluminum or aluminum composite material (ACM). In an embodiment, the diffuser is fabricated from a polycarbonate plastic material. In an embodiment, the diffuser is fabricated from an acrylic material. In an embodiment, the diffuser is a clear material. In an embodiment, the reflective surface is made from an aluminum material. In an embodiment, the reflective surface is a highly polished aluminum surface. In an embodiment, the reflective material is a plastic material displaying a highly polished reflective surface. 
       FIG. 3  is a perspective view of an illustrative embodiment of a light shelf  30  of the present invention having a plurality of the light transmitting louvers  10 . As shown in  FIG. 3 , the light shelf  30  includes two support beams  34  separated by, and engaged to, a center anchor bracket  32 . In the embodiment shown in  FIG. 3 , the light shelf  30  is integrated into structural members of a curtain wall  39 . For example, the center anchor bracket  32  can attach to a vertical mullion  36  of the curtain wall  39 . Attached to surface “a” of each of the support beams  34  are the plurality of louvers  10 . For example, in the embodiment depicted in  FIG. 3 , three of the louvers  10  engage each of the support beams  34 . The louvers  10  engage the support beam  34  through at least one of the connecting means  11 . In an embodiment, each of the louvers  10  are attached to the support beam  34  by running a screw through the support beam  34  and into connecting means  11 . The connecting means  11  can run an entire length of the louvers  10 . In an embodiment, each of the louvers  10  are attached to the support beam  34  by a shear clip. In an embodiment, each of the louvers  10  are attached to the support beam  34  by an adhesive bonding. 
       FIG. 4  is a perspective view of an illustrative embodiment of a light shelf  40  of the present invention having a plurality of the light transmitting louvers  20 . As shown in  FIG. 4 , the light shelf  40  includes two support beams  44  separated by, and engaged to, a center anchor bracket  42 . In the embodiment shown in  FIG. 4 , the light shelf  40  is integrated into structural members of a curtain wall  49 . For example, the center anchor bracket  42  can attach to a vertical mullion  46  of the curtain wall  49 . Attached to surface “a” of each of the support beams  44  are the plurality of louvers  20 . For example, in the embodiment depicted in  FIG. 4 , three of the louvers  20  engage each of the support beams  44 . The louvers  20  engage the support beams  44  through at least one of the connecting means  21 . In an embodiment, each of the louvers  20  are attached to the support beam  44  by running a screw through the support beam  44  and into connecting means  21 . The connecting means  21  can run an entire length of the louvers  20 . In an embodiment, each of the louvers  20  are attached to the support beam  44  by a shear clip. In an embodiment, each of the louvers  20  are attached to the support beam  44  by an adhesive bonding. 
     The support beams and anchor brackets of any of the light shelves of the present invention can be fabricated from an extruded aluminum. In an embodiment, the light shelves of the present invention serve as an interior extension to a curtain wall horizontal, reflecting sunlight deeper into the interior of a building by “bouncing” natural light up to the ceiling In an embodiment, the light shelves of the present invention serve as an interior extension to a curtain wall horizontal, diffusing sunlight to the space below the light shelf by “scattering” natural light down. 
       FIG. 5A  shows a floor plan view of the light shelf  30  of the present invention integrated into the structural members of the curtain wall  39 .  FIG. 5B  is a cross-sectional view taken along line A-A of  FIG. 5A . As illustrated in  FIG. 5B , sunlight rays s cross through a glass window  50  and reach the louvers  10 . The louvers  10  are positioned and attached to the support beams  34  such that rays of sunlight s hit the second element  14  and diffuses through the second element  14  to the space below V, thus providing a source of natural ambient light in the vicinity under the light shelf  30 . Sun rays s also are capable of hitting the third element  16 , where they are reflected off of the third element  16  in an upward direction towards the ceiling C. The light shelf  30  provides both natural ambient light to the area V below the light shelf  30 , as well as natural ambient light to an area D deep within the interior space of the room. 
       FIG. 6A  shows a floor plan view of the light shelf  40  of the present invention integrated into the structural members of the curtain wall  49 .  FIG. 6B  is a cross-sectional view taken along line B-B of  FIG. 6A . As illustrated in  FIG. 6B , sunlight rays s cross through a glass window  60  and reach the louvers  20 . The louvers  20  are positioned and attached to the support beams  44  at an angle such that sunlight s hits the reflective surface  26  of the first element  22  and reflects off of the reflective surface  26  onto the second element  24 . The reflective rays are diffused out towards the ceiling C, followed by incident rays bouncing off of the ceiling C and penetrating to an area D deep within the interior space of the room. The angle at which the louvers  20  are positioned and attached to the support beams  44  can be determined based on the buildings elevation and position to the sun. The angle will control the intensity of the reflected light which ultimately determines that amount of light wash to the interior of the space. The angle of the louvers  20  can be determined by the placement of the connecting means  21  for the fasteners that hold the louver  20  to the support beams  44 . 
       FIG. 7  is a side view of an illustrative embodiment of an end cap  70  of the present invention. The end cap  70  is a light shelf end treatment that can be used, for example, in punched opening applications. The end cap includes at least one catch  72  which helps engage the end cap  70  with a light transmitting louver of the present invention.  FIG. 8  shows a side view of end cap  70  positioned and engaged with the louver  20 . The end cap  70  is designed to provide engagement points for the lip  25  of the louver  20  via at least one catch  72 . The lip  25  engages the first element  22  and the end cap  70 . 
     The light shelves of the present invention can be attached directly to a curtain wall system or to a building structure if the window area is essentially a punched area. Any of the light shelves of the present invention can include end caps for punched opening applications. In an embodiment, a depth of the light shelves of the present invention range from about 20 inches up to about 40 inches. In an embodiment, the light shelves of the present invention have a depth of about 30 inches. In an embodiment, a length of the light shelves of the present invention range from 30 inches to about 72 inches. In an embodiment, the light shelves of the present invention have a length of about 60 inches. 
     It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.