Abstract:
An LED light band has a thin elongated housing with an open front face covered by an elongated transversely corrugated polycarbonate lens having crests and nadirs spaced at a first predetermined interval. A linear array of LEDs extending behind and along the bottom edge of the lens are spaced at a second predetermined interval different from the first. Because of the difference in the intervals, the light dispersion from the lens appears to the eye to be random so that, for example, a red lens can be used to suggest the presence of licking flames. The polycarbonate lens can be made by pressing long narrow lengths of flat polycarbonate in a sheet metal press.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to lighting fixtures and more particularly concerns the use of LED light bands in creating lighting effects. 
     LED technology can be used to facilitate simulation of natural phenomena. The shapes of the LED housings, the reflective and refractive qualities of the lenses and the configurations of the arrays, colors and diffusion patterns of the LEDs can be coordinated to produce a wide variety of effects. But the use of such coordination to produce, for example, attractive “twinkling starlight” or “licking flames” simulations, often comes with a high price tag. 
     One of the problems in some applications is that sheets of polycarbonate material, unlike metal sheets, cannot be economically, if at all, cold pressed. Polycarbonate LED lighting lenses are economical and, using presently known technology, crests and nadirs can, in some applications, be shaped into a sheet of polycarbonate material using a “wavy” roller. However, the rollers are limited in length so the nadirs and crests must run parallel to the length of the material. Thus, known technology cannot be used to create an elongated lens of polycarbonate with transverse crests and nadirs. But an elongated lens of polycarbonate with transverse crests and nadirs could be useful in the creation of attractive LED effects in long bands without any visual interruption of the simulated phenomena. 
     It is, therefore, an object of this invention to provide a relatively inexpensive elongated lens of polycarbonate with transverse crests and nadirs. It is also an object of this invention to provide a relatively inexpensive lens of polycarbonate capable of contributing to the attractive simulation of certain visual phenomena and images. A further object of this invention is to provide an LED light band which is capable of simulation of certain visual phenomena and images, such as “licking flames.” 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, an LED light band has a thin elongated housing with an open front face covered by an elongated polycarbonate lens. The lens has transverse corrugations with crests and nadirs at a first predetermined interval and a linear array of LEDs extending behind and along the bottom edge of the lens. The LEDs of the array are spaced at a second predetermined interval. The first and second predetermined intervals are different so that the lens display appears to be random. 
     The first predetermined interval is preferably greater than the second. The ratio of the first to second predetermined intervals is preferably approximately ⅔. Preferably, the first predetermined interval is approximately 2½″ and the second predetermined interval is approximately 1⅔″ with the depth of the corrugation from crest to nadir being approximately ½″, the height of the lens being approximately 15″ and the depth of the housing being approximately 2½″. 
     The housing has a rear wall with a lower vertical portion and a forwardly tilted upper portion. The base of the housing extends forwardly from the bottom of the lower vertical portion. Upper and lower opposed channels are attached to the top of the forwardly tilted upper portion and to the forward edge of the lower vertical portion, respectively, for sliding reception of the lens therebetween. 
     The linear array of LEDs are mounted on an elongated LED circuit board pitched toward the lens by a bracket extending lengthwise in the housing behind the lens and along the junction of the rear wall and base of the housing. The angle of the pitch is approximately 12°. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which: 
         FIG. 1  is a perspective view of the LED light band; 
         FIG. 2  is a front plan view of the LED light band of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view taken along the line  3 - 3  of  FIG. 2 ; 
         FIG. 4  is a cross-sectional view taken along the line  4 - 4  of  FIG. 2 ; 
         FIG. 5  is a cross-sectional view taken along the line  5 - 5  of  FIG. 4 ; 
         FIG. 6  is a perspective view of a typical end cap for the LED light band of  FIG. 1 ; 
         FIG. 7  is a perspective view of an outside corner for the LED light band of  FIG. 1 ; 
         FIG. 8  is a perspective view of an inside corner for the LED light band of  FIG. 1 ; and 
         FIG. 9  is a cross-sectional view of the LED light band of  FIG. 1  mounted on a parapet. 
     
    
    
     While the invention will be described in connection with a preferred embodiment thereof, it will be understood that it is not intended to limit the invention to that embodiment or to the details of the construction or arrangement of parts illustrated in the accompanying drawings. 
     DETAILED DESCRIPTION 
     Looking first at  FIGS. 1-3 , an LED light band  10  includes a thin, elongated housing  11  with an open front face covered by an elongated polycarbonate lens  13 . The lens  13  is transversely corrugated to provide vertically aligned crests  15  or nadirs  17  spaced at a first predetermined interval  19 , respectively. 
     Turning to  FIGS. 4-5 , a linear array of LEDs  21  extends behind and along the bottom edge of the lens  13 . The LEDs  21  of the array are spaced at a second predetermined interval  23 . As best seen in  FIG. 5 , the first and second predetermined intervals  21  and  23  are different. Therefore, the angles of reflection between consecutive LEDs  21  and the corrugated lens  13  are different and the dispersion of light through the lens  13  varies accordingly along the length of the lens  13 . 
     This variation of dispersion results in a random appearance of light to a passing observer such that, as the observer moves in relation to the light band  10 , the light seems to flicker. The effect may be accentuated by external conditions, such as wind striking the face of the lens  13  and causing slight and irregular distortions of the polycarbonate material of the lens  13 . If, for example, the lens  13  were red in color, the lens  13  would take on the appearance of a flickering flame. 
     As seen in  FIG. 5 , the first predetermined interval  19  is preferably greater than the second predetermined interval  23 . The ratio of the first to second predetermined intervals  19  to  23  is preferably approximately ⅔. Preferably, the first predetermined interval  19  is approximately 2½″ and the second predetermined interval  23  is approximately 1⅔″ with the depth  25  of the corrugation from crest  15  to nadir  17  being approximately ½″. Also preferably, as seen in  FIG. 4 , the height  27  of the lens  13  is approximately 15″ and the depth  29  of the housing  11  is approximately 2½″. 
     Continuing to look at  FIGS. 4-5 , the housing  11  has a rear wall  31  with a lower vertical portion  33  and a forwardly tilted upper portion  35 . The base  37  of the housing  11  extends forwardly from the bottom of the lower vertical portion  33  of the rear wall  31  and is turned upward, rearward and upward to form a seat  39  on and against which the lower edge and rear face of the lens  13  rests. The forwardly tilted upper portion  35  of the rear wall  31  extends to an upper channel  41  opposed to the seat  39 . The channel  41  has an internal flange  43  which secures the lens  13  in, and against the back inside face of, the channel  41 . As can be understood by reference to  FIG. 4 , the lens  13  can be mounted by sliding longitudinally onto the seat  39  and into the channel  41  or by vertical insertion into the channel  41  and rotation onto the seat  39 . The lower portion of the lens  13  is secured against the back of the seat  39  by the upper flange  45  of a facia  47  extending across the front of the upward portion of the base  37 . 
     The linear array of LEDs  21  are mounted on an elongated LED circuit board  51  pitched toward the lens  13  by clips  53  spaced lengthwise in the housing  11  behind the lens  13  and along the junction of the lower portion  33  of the rear wall  31  and the base  37  of the housing  11 . The angle  55  of the pitch is approximately 12°. 
     Turning to  FIGS. 6, 7 and 8 , accessories for the light band  10  include end caps  60 , outside corners  70  and inside corners  80 , respectively. The left end cap  60  shown has left end, top, bottom, front and rear walls  61 ,  63   65 ,  67  and  69 , respectively, contoured to enclose and conform to the left end of a light band  10  inserted into its open right face. The right end cap, not shown, is an opposite hand configuration of the left hand cap  60  shown. The outside corner  70  and inside corner  80  are right angle corners having frames  71 / 81  identical in cross-sectional configuration, each with a top, a bottom and a side wall  73 / 83 ,  75 / 85  and  77 / 87 , respectively, contoured for insertion into and conformance with the left and right ends of two light bands  10 . For the outside corner  70 , an outside piece of corner trim  79  completes the junction of the frames  71  and, for the inside corner  80 , an outside piece of corner trim  89  completes the junction of the frames  81 . 
     Looking at  FIG. 9 , one manner of mounting the light band  10  on a parapet P is illustrated. A base plate  91  is secured atop the parapet P, perhaps as shown by an anchor bolt  93 . A generally S-shaped mounting bracket  95  has a base portion  97 , an upward angled leg  99 , a horizontal top  101  and a downward vertical leg  103 . The base  37  of the light band  10  is positioned on the horizontal top  101  of the mounting bracket  95  with the front face of the base  37  and the front face of the leg  103  are in a common plane. Nested identical angle irons  105  and  107  are telescoped to a generally desired length adjustable by use of screws  109 . The distal ends of the nested angle irons  105  and  107  have flat extensions  111  and  113 , respectively. The upper flat extension  111  will be secured to the angled portion  35  of the housing  11 , as shown by screws  115 . The lower flat extension  113  will be secured to the mounting bracket  95 , the parapet P, the mounting plate  91  or such other structure as may be available, depending on the building/parapet structure. As shown, the lower flat extension  113  will be secured between the base portion  97  of the mounting bracket  95  and the base plate  91 . This is accomplished by bending the upper flat extension  111  at a point  117  below the screws  115  to generally position the lower flat extension  113  to be secured to the selected support structure. As shown, the lower flat extension  113  is bent at points  119  and  121  as required to accommodate the support structure and, once positioned between the base plate  91  and the mounting bracket  95 , is secured by an anchor bolt  123 , as shown extending into the parapet P. The bends  117 ,  119  and  121  and the positions of the screws  109  can then be adjusted to provide a most stable mount for the light band  10 . To finish the installation, the facia  47  can be selected to extending across the front of the upward portion of the base  37  and also across the leg  103  of the mounting bracket  95  to the base plate  91  on the parapet P. 
     A lens  10  suitable for the purposes of this disclosure has been made by starting with a roll, perhaps  450 ′ or more in length, of 15.5″ wide×⅛″ thick flat polycarbonate stock. The stock is rolled off its drum 7.5′ to 8.0′ at a time into a sheet metal die press where the desired corrugation is pressed into the unrolled polycarbonate. A 230 T hydraulic press has been found suitable to the purpose. After each 7.5′ to 8.0′ length is pressed, the press is relaxed to receive the next unrolled 7.5′ to 8.0′ length of polycarbonate. Preferably, each next length is rolled out only so far as will permit the die to overlap the trailing end of the previous length. As the pressed polycarbonate exits the press it is wound onto a coiler from which it can later be unwound and cut into any length desired. 
     Thus, it is apparent that there has been provided, in accordance with the invention, a corrugated lens LED light band that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with a specific embodiment thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art and in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit of the appended claims.