Patent Publication Number: US-2016223164-A1

Title: Wall washer lighting system with light emitter, optical lens and reflector

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 62/109,837, filed Jan. 30, 2015, and titled WALL WASHER LIGHTING SYSTEM WITH LIGHT EMITTER, OPTICAL LENS AND REFLECTOR, which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to wall washer lighting and, more particularly, to secondary optics for wall washer lighting. 
     BACKGROUND 
     Wall washer lighting systems generally have an optical component focused on distributing light along a vertical plane. Traditionally, fluorescent, or linear fluorescent, lamps have been used as the light source, and a reflector is used to kick light out for a wall wash effect from the lamp. Such a reflector is designed to uniformly illuminate the wall vertically, with no special considerations taken in the horizontal plane. As a result, the horizontal distribution and, therefore, the spacing criteria (SC) of the wall washer fixture are both dependent on the natural distribution of light from the lamp in the horizontal direction. A wall washer fixture with a small SC will result in more fixtures being required to sufficiently illuminate the wall, with increased material and labor resulting from the additional fixtures that are required. A small SC may also generate hot spots, which are areas of greater light intensity, on the wall right below the fixtures. 
     Light emitting diodes (LEDs) have become an increasingly popular lamp source in various luminaires, including wall washers. LEDs have been recognized as providing increased efficiency and decreased costs, relative to conventional lamp sources, and also offer advantages including long life, compact size, and direct illumination. For these reasons, lighting manufacturers have used LEDs in wall washer designs and also in the design of linear wall washers. For linear wall washers, manufacturers may construct LED strips with multiple LEDs, spaced so that the LED strips physically represent linear fluorescent lamps. Despite the many previously-discussed advantages of using LEDs in wall washer systems, LED wall washers encounter the same issues as fluorescent wall washers with regard to lighting distribution, spacing criteria, and hot spots. 
     Therefore, it is desirable to provide a wall washer system with increased efficiency and decreased costs, relative to conventional lamp sources, as well as providing uniform lighting distribution, increased spacing criteria, and elimination of hot spots. The present disclosure is responsive to such an endeavor and is directed to one or more of the problems or issues set forth above. 
     SUMMARY OF THE DISCLOSURE 
     In one aspect, a wall washer lighting system includes a light emitter mounted relative to a first surface that is about perpendicular to a second surface. The wall washer lighting system is configured to direct light from the light emitter toward the second surface. The wall washer lighting system includes an optical lens shaped to redirect light from the light emitter about uniformly along a horizontal axis of the second surface, with the horizontal axis extending to both sides of the light emitter. The wall washer lighting system also includes a reflector shaped to redirect light along a vertical axis of the second surface, the reflector uniformly shaped along its horizontal axis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevational view in partial section depicting an exemplary embodiment of a wall washer lighting system, according to one aspect of the present disclosure; 
         FIG. 2  is a side view in partial section of a light emitter and optical lens of the wall washer lighting system of  FIG. 1 ; 
         FIG. 3  is a front perspective view of the optical lens of  FIGS. 1 and 2 ; 
         FIG. 4  is a back perspective view of the optical lens of  FIGS. 1 and 2 ; and 
         FIG. 5  is a bottom perspective view of an exemplary linear wall washer lighting system including a plurality of linearly aligned light emitters, according to another aspect of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , there is shown an elevational view of a wall washer lighting system  10 , according to an exemplary embodiment of the present disclosure. The exemplary wall washer lighting system  10  is shown mounted relative to a first surface  12 , such as a ceiling, which is about perpendicular to a second surface  14 , such as a wall. The wall washer lighting system  10  is configured to direct light from one or more light sources, examples of which will be provided below, toward the second surface  14 . 
     The wall washer lighting system  10  may generally include a housing  16 , such as a rectangular shaped housing, supporting and/or protecting at least a light emitter  18 , a reflector  20 , and an optical lens  22 . According to the exemplary embodiment, the housing  16  is configured to support the wall washer lighting system  10  relative to the first surface  12 . For example, when properly installed, the housing  16  may support the light emitter  18 , reflector  20 , and optical lens  22  above, or recessed relative to, the first surface  12 . Additional components, such as fasteners and the like, may be required to secure the position of the housing  16  relative to the first surface  12 . 
     The light emitter  18  may be supported within the housing  16  at a position and orientation for directing light from the light emitter  18  toward the second surface  14 . For example, a vertical support structure  24  may be provided within the housing  16  and may provide a surface for mounting the light emitter  18 . As shown, the light emitter  18  may have a vertical orientation when secured to or mounted on the support structure  24 . 
     The light emitter  18  may be, but is not limited to, an LED emitter commonly used in commercial lighting in combination with a driver. Alternatively, for example, the light emitter  18  may be a laser diode or other alternative diode light source. The light emitter  18  may include a single chip containing one or more light sources or may include multiple chips. According to the example provided, the light emitter  18  may be provided on a substrate  26 , or chip, and may include a primary optic  28  for protecting and/or shaping the light output of the light emitter  18 . The primary optic  28  may, according to some embodiments, have a semi-circular shape. The light emitter  18 , according to the exemplary embodiment, may also be referred to as a planar light emitter. 
     The reflector  20  may be shaped to redirect light along a vertical axis  30  of, or parallel to, the second surface  14 . More specifically, the reflector  20  may be shaped to redirect, or reflect, light from the light emitter  18  and distribute it vertically along the second surface  14 . The position, including orientation, of the light emitter  18 , relative to the second surface  14 , along with the configuration of the reflector  20 , are all selected based on a desired vertical light intensity distribution or wall wash effect provided by the wall washer lighting system  10 . 
     The reflector  20  may include a first segment  32  closest to the light emitter  18  that is curvilinear and a second segment  34  furthest from the light emitter  18  that is about flat, or linear. The first segment  32  may be shaped to redirect light downward and toward a lower portion of the second surface  14 , while the second segment  34  may be shaped to redirect light toward an upper portion of the second surface  14 . It should be appreciated that, since the exemplary light emitter  18  is directional (i.e., illuminating only 180 degrees), light is only being emitted from a light emitting side  36  of the substrate  26 . Some portions of the light need not be redirected and, thus, may be emitted directly from the light emitter  18  toward the second surface  14  and, possibly, a lower surface, or floor. As will be discussed below with reference to  FIG. 5 , the reflector  20  may be uniformly shaped along its horizontal axis. 
     The optical lens  22  may be shaped to redirect light from the light emitter  18  about uniformly along a horizontal axis of the second surface  14 , as will be described below. The optical lens  22  may be positioned over the primary optic  28  and, therefore, may be referenced as a secondary optic. In addition, a transparent cover  38  may be provided to enclose the housing  16  and protect the components therein. As shown, the transparent cover  38  may be angled relative to the first surface  12 . 
     Turning now to  FIG. 2 , the optical lens  22  will be discussed in greater detail. As stated above, the optical lens  22  may be shaped to redirect light from the light emitter  18  about uniformly along a horizontal axis  50  of the second surface  14 . As shown, the optical lens  22  may have at least two lobes  52  and  54 , with each of the lobes  52  and  54  being positioned on either side of a centerline  56  through the light emitter  18  and having a generally convex surface shaped to achieve a greater intensity distribution in the horizontal plane than what would be achieved without the optical lens  22 . That is, the optical lens  22  may be shaped to redirect light away from the centerline  56  to increase the light intensity distribution in the horizontal plane. 
     An inner surface  57  of the optical lens  22  may have a shape matching that of the primary optic  28  or may have an alternative shape. According to some embodiments, the inner surface  57  may be shaped to contribute to the horizontal distribution of the light. 
     According to the exemplary embodiment, the optical lens  22  may have four lobes  52 ,  54 ,  58 , and  60  and two axes  62  and  64  of symmetry, as shown in  FIGS. 3 and 4 . Although a specific embodiment is shown, it should be appreciated that alternative embodiments, including different lens configurations, may be substituted for the exemplary embodiment. The optical lens  22  of the preferred embodiment is designed to be made of acrylic, however the optical lens  22  could be make of any material with high light transmittance, including, for example, polycarbonate, resin, and glass. The surface of the optical lens  22  may be smooth or textured. 
     Turning now to  FIG. 5 , an exemplary linear wall washer lighting system  70  is shown. The linear wall washer lighting system  70  is similar to the wall washer lighting system  10  described above; however, the linear wall washer lighting system  70  includes a plurality of linearly aligned light emitters  72 , with each of the linearly aligned light emitters including a separate optical lens  74 . A single reflector  76  may be provided for the linear wall washer lighting system  70 . As mentioned above, the reflector  76  may be uniformly shaped along its horizontal axis  78 . In addition, the reflector  76  may have a length corresponding to the number of light emitters used. 
     The wall washer lighting system  10  of the present disclosure provides increased horizontal distribution of light transmitted from the wall washer. As such, a larger spacing criteria is provided, requiring less fixtures, which results in less material and labor. Further, since the spacing criteria is greater, less hot spots are generated. As a result, the wall washer lighting system  10  of the present disclosure provides a more uniform lighting distribution with increased efficiency and decreased costs. 
     It should be understood that the above description is intended for illustrative purposes only, and is not intended to limit the scope of the present disclosure in any way. Thus, those skilled in the art will appreciate that other aspects of the disclosure can be obtained from a study of the drawings, the disclosure and the appended claims.