Abstract:
LED lighting systems employing plano optics, direct dissipation heat sinks, and linear AC direct current drivers are disclosed. The heat sink is configured to provide thermal management for the LED lights and AC linear current driver circuit elements, as well as to provide a means for holding lenses having diffractive optical elements. The LED lighting systems are compact, energy efficient, and may be used in many conventional incandescent or fluorescent lighting applications. Lenses having diffractive optical elements are designed to redirect light radiated from the LEDs into other directions.

Description:
RELATED APPLICATION INFORMATION 
       [0001]    The present application claims priority under 35 U.S.C. Section 119(e) to U.S. Provisional Patent Application Ser. No. 62/006,429 filed Jun. 2, 2014, entitled “LED LIGHTING FIXTURE DESIGN WITH PLANO OPTICS, DIRECT DISSIPATION HEAT SINK AND LINEAR AC DIRECT DRIVE,” the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates in general to solid state lighting systems. More particularly, the invention is directed to LED lighting systems having integrated heat sinks with lenses having diffractive optical elements. 
         [0004]    2. Description of the Related Art 
         [0005]    Solid state lighting apparatuses are becoming increasingly more common as they offer higher efficiencies and longer lifetimes as compared to conventional light sources such as incandescent lamps. However, conventional packaging of LED lighting systems may not adequately address the thermal management aspects, as well as emission pattern requirements, for many applications. 
         [0006]    Accordingly, a need exists to improve the packaging of LED lighting systems. 
       SUMMARY OF THE INVENTION 
       [0007]    In the first aspect, a lighting system is disclosed. The lighting system comprises an elongated heat sink, the heat sink having a back surface configured for mounting, the heat sink further comprising an internal cavity running along the length of the heat sink, the inner cavity having a generally flat bottom surface and two walls extending perpendicular from the generally flat bottom surface, each wall having a groove running along the length of the heat sink, each groove spaced equidistant from the flat bottom surface. The lighting system further comprises a printed circuit board assembly comprising a printed circuit board mounted on the generally flat bottom section of the heat sink, one or more light emitting diodes (“LEDs”) mounted on the printed circuit board, one or more electrical devices configured to energize the LEDs, a plurality of wire connectors configured for electrically coupling power cables to the printed circuit board. The lighting system further comprises a lens mounted in the grooves of the heat sink, a first end cap coupled to one end of the elongated heat sink, and a second end cap coupled to the other end of the elongated heat sink, the one end opposite that of the other end. 
         [0008]    In a first preferred embodiment, the back surface is generally parallel with the generally flat bottom surface of the internal cavity. The back surface is preferably generally parallel with the generally flat bottom surface of the internal cavity. The acute angle is preferably approximately 30 degrees. The lens preferably comprises a plurality of diffractive optical elements. The diffractive optical elements preferably comprise a diffractive grating having a periodicity in the range of approximately 10 micrometers to approximately 200 micrometers. The diffractive grating preferably comprises a plurality of triangularly-shaped ridges, each ridge having a first and a second grating surface, the first and the second grating surfaces slanted symmetrically opposite to each other, the first and second grating surfaces forming a predetermined angle, wherein the predetermined angle is in the range of approximately 50 degrees to approximately 120 degrees. 
         [0009]    The diffractive grating preferably comprises a plurality of triangularly-shaped ridges, each ridge having a first and a second grating surface, the first and the second grating surfaces slanted asymmetrically opposite to each other, the first and second grating surface forming a predetermined angle, wherein the predetermined angle is in the range of approximately 80 degrees to approximately 150 degrees. The diffractive grating preferably comprises a plurality of curved ridges emerging from the body of the lenses, each ridge formed by a symmetrical arc having one center emerging from the body of the lenses characterized by a predetermined angle, wherein the predetermined angle is in the range of approximately 50 degrees to approximately 120 degrees. 
         [0010]    The diffractive grating preferably comprises a plurality of curved ridges, each ridge having a first arced and a second arced grating surface, the first and the second grating surfaces slanted asymmetrically opposite to each other, the first and second grating surfaces emerging from the body of the lenses characterized by a predetermined angle, wherein the predetermined angle is in the range of approximately 80 degrees to approximately 150 degrees. The one or more electrical devices configured to energize the LEDs preferably further comprises a power supply configured to energize the plurality of LEDs using alternating current (“AC”) line current without employing a transformer. 
         [0011]    In a second aspect, a lighting system is disclosed. The lighting system comprises an elongated heat sink, the heat sink having a back surface configured for mounting, the heat sink further comprising an internal cavity running along the length of the heat sink, the inner cavity having a generally flat bottom surface and two walls extending perpendicular from the generally flat bottom surface, each wall having a groove running along the length of the heat sink, each groove spaced equidistant from the flat bottom surface. The lighting system further comprises one or more light emitting diodes (“LEDs”) thermally mounted to the flat bottom surface, the LEDs mounted to emit light away from the flat bottom surface, and a lens mounted in the grooves of the heat sink. 
         [0012]    In a second preferred embodiment, the lens comprises a diffractive grating having a periodicity in the range of approximately 10 micrometers to approximately 200 micrometers. The diffractive grating preferably comprises a plurality of triangularly-shaped ridges, each ridge having a first and a second grating surface, the first and the second grating surfaces slanted symmetrically opposite to each other, the first and second grating surface forming a predetermined angle, wherein the predetermined angle is in the range of approximately 50 degrees to approximately 120 degrees. The diffractive grating preferably comprises a plurality of triangularly-shaped ridges, each ridge having a first and a second grating surface, the first and the second grating surfaces slanted asymmetrically opposite to each other, the first and second grating surface forming a predetermined angle, wherein the predetermined angle is in the range of approximately 80 degrees to approximately 150 degrees. 
         [0013]    The diffractive grating preferably comprises a plurality of curved ridges emerging from the body of the lenses, each ridge formed by a symmetrical arc having one center emerging from the body of the lenses characterized by a predetermined angle, wherein the predetermined angle is in the range of approximately 50 degrees to approximately 120 degrees. The diffractive grating preferably comprises a plurality of curved ridges, each ridge having a first arced and a second arced grating surface, the first and the second grating surfaces slanted asymmetrically opposite to each other, the first and second grating surfaces emerging from the body of the lenses characterized by a predetermined angle, wherein the predetermined angle is in the range of approximately 80 degrees to approximately 150 degrees. 
         [0014]    In a third aspect, a lighting system is disclosed. The lighting system comprises an elongated heat sink, the heat sink having a back surface configured for mounting, the heat sink further comprising an internal cavity running along the length of the heat sink, the inner cavity having a generally flat bottom surface and two vertical walls, each vertical wall having a groove running along the length of the heat sink, each groove spaced equidistant from the flat bottom surface, and a lens mounted in the grooves of the heat sink. 
         [0015]    In a third preferred embodiment, the back surface is generally parallel with the generally flat bottom surface of the internal cavity. The back surface preferably generally forms an acute angle with the generally flat bottom surface of the internal cavity. 
         [0016]    These and other features and advantages of the invention will become more apparent with a description of preferred embodiments in reference to the associated drawings. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a side, perspective view of an LED lighting system in one or more embodiments. 
           [0018]      FIG. 2  is a side, perspective view of a partially disassembled LED lighting system. 
           [0019]      FIG. 3  is a cross-sectional view of the heat sink. 
           [0020]      FIG. 4  is a cross-sectional view of the heat sink with the lens and printed circuit board assembly. 
           [0021]      FIG. 5  is a side, perspective view of the center section of the LED lighting system showing the connections to the power cord. 
           [0022]      FIG. 6  is a side, perspective view of an LED lighting system having LEDs positioned at an angle with respect to the mounting surface in one or more embodiments. 
           [0023]      FIG. 7  is a side, perspective view of a partially disassembled LED lighting system. 
           [0024]      FIG. 8  is a cross-sectional view of the heat sink where the LEDs are positioned at an angle with respect to the mounting surface in one or more embodiments. 
           [0025]      FIG. 9  is a cross-sectional view of the heat sink with the lens and printed circuit board assembly where the LEDs are positioned at an angle with respect to the mounting surface in one or more embodiments. 
           [0026]      FIG. 10  is a front, perspective view of the center section of the LED lighting system showing the connections to the power cord. 
           [0027]      FIG. 11  is a side, perspective view of an LED lighting system in one or more embodiments. 
           [0028]      FIG. 12  is a side, perspective view of a partially disassembled LED lighting system. 
           [0029]      FIG. 13  is a cross-sectional view of the heat sink. 
           [0030]      FIG. 14  is a schematic representation of an LED lighting system illustrating light radiated from an LED, where the lens does not have diffractive optical elements. 
           [0031]      FIG. 15  is a typical emission pattern of the lighting system depicted in  FIG. 14 . 
           [0032]      FIG. 16  is a schematic representation of an LED lighting system illustrating light radiated from an LED through a lens, where the lens has symmetrical, saw-tooth ridges. 
           [0033]      FIG. 17  is a schematic representation of an LED lighting system illustrating light radiated from an LED through a lens, where the lens has symmetrical, curved ridges. 
           [0034]      FIG. 18  is a typical emission pattern of the lighting system depicted in  FIG. 17 . 
           [0035]      FIG. 19  is a schematic representation of an LED lighting system illustrating light radiated from an LED through a lens, where the lens has asymmetrical, saw-tooth ridges. 
           [0036]      FIG. 20  is a schematic representation of an LED lighting system illustrating light radiated from an LED through a lens, where the lens has asymmetrical, curved ridges. 
           [0037]      FIG. 21  is a schematic electrical circuit diagram of the LED power source in one or more embodiments. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]    One or more embodiments are directed to LED display case fixtures capable of replacing inefficient fluorescent tubes in commercial freezer and display cases. The LED lighting systems may provide a versatile, modular solution for commercial cold case and retail display case lighting applications. Embodiments may offer reduced energy costs, higher quality lighting, reduced maintenance costs, and significantly better lumen maintenance over the service life. 
         [0039]    Embodiments may exhibit up to 80% power savings over the commonly used fluorescent tube ballast combinations and, due to reduced heat generation, reduced strain and demand on refrigeration compressors and controls. Embodiments having AC current drivers eliminate the need for bulky external ballasts which may be the primary weakness of traditional lighting systems. Embodiments having a custom optical design assure the perfect light distribution for many applications. 
         [0040]    One or more embodiments are directed to LED lighting fixtures having plano optics, heat sinks which dissipate heat directly, and linear AC direct current drivers. One or more embodiments employ integrated power converters on printed circuit boards having linear AC direct LED drivers, and micro optics lenses (i.e., plano optics) to change the direction of the emitted radiation. One or more embodiments offer a compact profile that saves space in many applications. 
         [0041]    Conventional LED lighting fixtures often protrude from the ceiling and may require significant space. Moreover, many applications require a specific beam emission pattern and direction such as when illuminating products on the shelves. In an embodiment, the special design of the extruded heat sink enables direct heat dissipation. Specially designed plano optics uses minimum space and allows light to radiate at designated angles. The linear AC direct LED driver uses minimum components to save space. 
         [0042]    One or more embodiments are directed to cabinet lighting or storage boxes which may need a special angle of lighting. One or more embodiments project light output uniformly, and have a unique lens designed to solve the problem of different beam direction requirements. Embodiments enable user to illuminate a desired location, and position. 
         [0043]      FIGS. 1-5  illustrate a lighting system  101  in one or more embodiments. As depicted in  FIG. 1 , the lighting system  101  comprises an elongated heat sink  110 , a lens  130 , a first end cap  150 , and a second end cap  154 . As used herein, heat sinks may refer to passive heat exchangers that cool devices by dissipating heat to the surrounding medium, and may be fabricated by various manufacturing techniques including extrusion. In one or more embodiments, heat sinks may be fabricated in aluminum, aluminum alloys, or other materials for example. In one or more embodiments, single, one-piece heat sinks are contemplated. 
         [0044]      FIG. 2  illustrates a partially exploded view of the lighting system  101 . The first end cap  150  has an end cap base  152  which attaches to the heat sink  110  through an end cap plate  160  with a plurality of screws  166 . The end cap base  152  is configured to receive an electrical connector  162  which is held in place with the nut  164 . The electrical connector  162  receives the power cord  170  which provides power to the LEDs. Housing  158  is placed over the end cap base  152 . 
         [0045]    The second end cap  154  has a second end cap base  156  which attaches to the heat sink  110  through an end cap plate  160  with a plurality of screws  166 . Housing  158  is placed over the end cap base  156 . A printed circuit board assembly  140  is placed in the heat sink  110 . 
         [0046]      FIG. 3  is a side, cross-sectional view of the elongated heat sink  110 . The heat sink has a back surface  112  configured for mounting and an internal cavity  114  running along the length of the heat sink  110 . The inner cavity  114  has a generally flat bottom surface  116  and two walls  118   a  and  118   b  running perpendicular from the bottom surface  116 . Each wall  118   a  and  118   b  has a groove  120   a  and  120   b  running along the length of the heat sink  110 . Each of the grooves  120   a  and  120   b  are spaced equidistant from the flat bottom surface  116 . The back surface  112  is generally parallel with the generally flat bottom surface  116  of the internal cavity  114 . 
         [0047]      FIG. 4  is a cross-sectional view of the heat sink  110 . The printed circuit board assembly  140  is placed in the heat sink  110 . The printed circuit board assembly  140  comprises a printed circuit board  142  mounted on the generally flat bottom section  116 , one or more light emitting diodes (“LEDs”)  144  mounted on the printed circuit board  142 , one or more LED current drivers  146 , and a plurality of wire connectors  148  configured for electrically coupling power cables  170  (see  FIG. 2 ) to the printed circuit board  142 . In one or more embodiments, the LED current drivers  146  may comprise one or more electrical devices or components, as discussed below and illustrated in  FIG. 21 .  FIG. 4  also illustrates the lens  130  secured in the grooves  120   a  and  120   b  to the heat sink  110 . 
         [0048]      FIG. 5  illustrates the electrical connections of the power cord  170  to the printed circuit board assembly  140 . In one or more embodiments, the power cord has a live or “hot” wire  172 , a neutral wire  174 , and a ground wire  176 . The hot wire  172  and the neutral wire  174  are connected to respective wire connectors  148 , and the ground wire  176  is connected to the ground tab  122 . 
         [0049]      FIGS. 6-10  illustrate a lighting system  201  having LEDs positioned at an angle with respect to the mounting surface in one or more embodiments. As depicted in  FIG. 6 , the lighting system  201  comprises an elongated heat sink  210 , a lens  230 , a first end cap  250 , and a second end cap  254 .  FIG. 7  illustrates a partially exploded view of the lighting system  201 . The first end cap  250  has an end cap base  252  which attaches to the heat sink  210  through an end cap plate  260  with a plurality of screws  166 . The end cap base  252  is configured to receive the electrical connector  162  which is held in place with the nut  160 . The electrical connector  162  receives the power cord  170  which provides power to the LEDs. Housing  258  is placed over the end cap base  252 . 
         [0050]    The second end cap  254  has a second end cap base  256  which attaches to the heat sink  210  through an end cap plate  260  with a plurality of screws  166  Housing  258  is placed over the end cap base  256 . A printed circuit board assembly  140  is placed in the heat sink  210 . 
         [0051]      FIG. 8  is a side, cross-sectional view of the elongated heat sink  210 . The heat sink has a back surface  212  configured for mounting the lighting system  201 , and an internal cavity  214  running along the length of the heat sink  210 . The inner cavity  214  has a generally flat bottom surface  216  and two walls  218   a  and  218   b  running perpendicular to the flat bottom surface. Each wall  218   a  and  218   b  has a groove  220   a  and  220   b  running along the length of the heat sink  210 . Each of the grooves  220   a  and  220   b  are spaced equidistant from the flat bottom surface  216 . The flat bottom surface  216  forms an acute angle α  217  with respect to the back surface  212 . In one or more embodiments, the acute angle α  217  is approximately 30 degrees. 
         [0052]      FIG. 9  is a cross-sectional view of the heat sink  210 . The printed circuit board assembly  140  is placed in the heat sink  110 . The printed circuit board assembly  140  comprises a printed circuit board  142  mounted on the generally flat bottom section  216 , one or more light emitting diodes (“LEDs”)  144  mounted on the printed circuit board  142 , one or more LED current drivers  146 , and a plurality of wire connectors  148  configured for electrically coupling power cables  170  (see  FIG. 2 ) to the printed circuit board  142 .  FIG. 9  also illustrates the lens  230  secured in the grooves  220   a  and  220   b  to the heat sink  310 . 
         [0053]      FIG. 10  illustrates the electrical connections of the power cord  170  to the printed circuit board assembly  140 . In one or more embodiments, the power cord has a live or “hot” wire  172 , a neutral wire  174 , and a ground wire  176 . The hot wire  172  and the neutral wire  174  are connected to respective wire connectors  148 , and the ground wire  176  is connected to the ground tab  222 . 
         [0054]      FIGS. 11-13  illustrate a lighting system  301  having LEDs in one or more embodiments. As depicted in  FIG. 11 , the lighting system  301  comprises an elongated heat sink  310 , a lens  330 , a first end cap  350 , and a second end cap  354 .  FIG. 12  illustrates a partially exploded view of the lighting system  301 . The first end cap  350  has an end cap base  352  which attaches to the heat sink  310  through an end cap plate  360  with a plurality of screws  166 . The second end cap  354  has a second end cap base  356  which attaches to the heat sink  310  through an end cap plate  360  with a plurality of screws  166 . A printed circuit board assembly  340  is placed in the heat sink  210 . The printed circuit board assembly  340  comprises a printed circuit board mounted on the generally flat bottom section  316 , one or more light emitting diodes (“LEDs”)  144  mounted on the printed circuit board, one or more LED current drivers, and a plurality of wire connectors  348  configured for electrically coupling power cables  170  (see  FIG. 2 ) to the printed circuit board  142 . 
         [0055]      FIG. 13  is a side, cross-sectional view of the elongated heat sink  310 . The heat sink  310  has a back surface  312  configured for mounting the lighting system  301 , and an internal cavity  314  running along the length of the heat sink  310 . The inner cavity  314  has a generally flat bottom surface  316  and two walls  318   a  and  318   b  running perpendicular to the flat bottom surface  316 . Each wall  318   a  and  318   b  has a groove  320   a  and  320   b  running along the length of the heat sink  310 . Each of the grooves  320   a  and  320   b  are spaced equidistant from the flat bottom surface  316 . The flat bottom surface  316  is parallel with the back surface  312 . 
         [0056]      FIG. 14  is a schematic representation of a lighting system  401  having a heat sink  410 , an LED  144 , and a flat lens  430  having no diffractive optical elements. The light  405  radiating from the LED  144  passes through the flat lens  430 , and illuminates the surroundings.  FIG. 15  is a typical emission pattern  480  of the LED  144  and the flat lens  430  without diffractive optical elements. In this configuration, the light  405  radiates between approximately −45 degrees to approximately +45 degrees with respect to the normal of the lens  430 . 
         [0057]      FIGS. 16-20  are schematic representations of light systems employing lenses having diffractive optical elements.  FIG. 16  depicts a lighting system  501  employing diffractive optical elements on the bottom surface of the lens  530 , where the diffractive optical elements comprise a plurality of triangularly-shaped ridges  1  formed by a first surface  2  and a second surface  3 . The first surface  2  and the second surface  3  are slanted symmetrically opposite to each other with respect to the normal of the lens  530 , depicted by the Z-axis. The periodicity of the ridges is in the range of approximately 10 micrometers to 200 micrometers. The intersection of the first surface  2  and the second surface  3  forms a predetermined angle θ 501    503 , wherein the predetermined angle θ 501    503  is in the range of approximately 50 degrees to approximately 120 degrees in one or more embodiments. 
         [0058]      FIG. 17  depicts a lighting system  601  employing diffractive optical elements on the bottom surface of the lens  630 , where the diffractive optical elements comprise a plurality of curved ridges  4  having a periodicity in the range of approximately 10 micrometers to 200 micrometers. The ridges  4  are symmetrical and emerge from the body of the lens  630  at point  5 , extend to the distal point  6  which coincides with the center normal of the ridge depicted by the z-axis, and curves back to the body of the lens  630  to point  7 . The ridge  4  is a symmetrical arc having one center. The ridge  4  emerges from the body of the lens  630  having a difference in slope in the range of approximately 50 degrees to approximately 120 degrees.  FIG. 18  is a typical emission pattern  680  of the lighting system  601 . In this configuration, the light  605  radiates having a first lobe  602  centered at approximately −30 degrees and a second lobe  684  centered at approximately +30 degrees. 
         [0059]      FIG. 19  depicts a lighting system  701  employing diffractive optical elements on the bottom surface of the lens  730 , where the diffractive optical elements comprise a plurality of asymmetrical, triangular shaped ridges  10  formed by a first surface  11  and a second surface  12 . The first surface  11  and the second surface  12  are slanted asymmetrically opposite to each other with respect to the normal of the lens  730 , depicted by the Z-axis. The periodicity of the ridges  10  is in the range of approximately 10 micrometers to 200 micrometers. The intersection of the first surface  11  and the second surface  12  forms a predetermined angle θ 701    703 , wherein the predetermined angle θ 701    703  is in the range of approximately 80 degrees to approximately 150 degrees in one or more embodiments. 
         [0060]      FIG. 20  depicts a lighting system  801  employing diffractive optical elements on the bottom surface of the lens  830 , where the diffractive optical elements comprise a plurality of asymmetrical, arc shaped ridges  14  formed by a first surface  16  and a second surface  18 . The first surface  16  and the second surface  18  are slanted asymmetrically opposite to each other with respect to the normal of the lens  830 , depicted by the Z-axis. The ridges  14  are asymmetrical and emerge from the body of the lens  830  at point  15 , extend to the distal point  17  which is offset with respect to the center normal of the ridge depicted by the z-axis, and curves back to the body of the lens  830  to point  19 . Ridge  14  has two asymmetrical arcs. The ridge  14  emerges from the body of the lens  830  having a difference in slope in the range of approximately 80 degrees to approximately 150 degrees. The periodicity of the ridges  14  is in the range of approximately 10 micrometers to 200 micrometers. The intersection of the first surface  16  and the second surface  18  forms a predetermined angle θ 801    803 , wherein the predetermined angle θ 801    803  is in the range of approximately 80 degrees to approximately 150 degrees in one or more embodiments. 
         [0061]      FIG. 21  is a schematic diagram of the electrical circuit  901  for energizing LEDs  910   a - 910   x . An AC power source  902  is connected to a bridge rectifier  908  through fuse  904  and resistor  906 . Pin  2  of the bridge  908  is connected to ground, and pin  4  of the bridge  908  is connected to a drive circuit employing a stack of Three-Terminal Current Controllers (“TTCC”)  920   a ,  920   b , and  920   c . The TTCC  920   a - 920   c  is configured in parallel with the LED strings. Pin  4  of the bridge  908  is connected to LEDs  910   a ,  910   b , and  910   c , in parallel with LEDs  910   f ,  910   g , and  910   h , in parallel with LEDs  910   k ,  9101 , and  910   m , in parallel with LEDs  910   p ,  910   q , and  910   r . LEDs  910   d  and  910   e , are in parallel with LEDs  910   i  and  910   j , in parallel with  910   n  and  910   o , in parallel with LEDs  910   s  and  910   t , and in parallel with resistor  930 . The cathodes of LEDs  910   c ,  910   h ,  910   m , and  910   r  are connected to the anodes of LEDs  910   d ,  910   i ,  910   s , and resistor  930 . Pin  4  of the bridge  908  is also connected to resistor  940 , which leads to ground via diode  938  and is employed to bias transistor  936 . Pin  4  of bridge  908  is also connected to resistor  942 , which in turn leads to pin  3  of TTCC  940   a  as well as diode  932 . Pin  4  of TTCC  920   a  is connected to pin  3  of TTCC  920   b , as well as to a parallel combination of LEDs  910   u ,  910   v ,  910   w , and  910   x . Pins  4 ,  5 , and  6  of TTCC  920   b  are connected to transistor  936 , as well as resistor  924  which act as a path to LEDs  910   u ,  910   v ,  910   w , and  910   x . Transistor  936  is also connected to pin  3  of TTCC  920   c.    
         [0062]    Although the invention has been discussed with reference to specific embodiments, it is apparent and should be understood that the concept can be otherwise embodied to achieve the advantages discussed. The preferred embodiments above have been described primarily as LED lighting systems. In this regard, the foregoing description of the LED lighting systems are presented for purposes of illustration and description. 
         [0063]    Furthermore, the description is not intended to limit the invention to the form disclosed herein. Accordingly, variants and modifications consistent with the following teachings, skill, and knowledge of the relevant art, are within the scope of the present invention. The embodiments described herein are further intended to explain modes known for practicing the invention disclosed herewith and to enable others skilled in the art to utilize the invention in equivalent, or alternative embodiments and with various modifications considered necessary by the particular applications or uses of the present invention.