Abstract:
A lighting unit including at least one elongated substrate having a plurality of light-emitting optoelectronic devices mounted thereon and an elongated housing supporting the elongated substrate. The housing includes integrally-formed reflectors positioned adjacent the optoelectronic devices. The lighting unit also includes a translucent output panel that transmits light from the optoelectronic devices. The light unit has a first wiring harness for connection to a power source, and a second wiring harness connectable to an adjacent lighting unit.

Description:
RELATED APPLICATIONS 
   This is a non-provisional patent application of U.S. provisional Patent Application Ser. No. 60/385,025 filed on Jun. 3, 2002, which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   This invention relates generally to lighting fixtures, and more particularly to fixtures that provide accent lighting. 
   BACKGROUND OF THE INVENTION 
   In commercial applications, accent lighting is typically used to capture the attention of potential customers. Accent lighting may highlight or supplement a primary display of some sort. Accent lighting may also be used to highlight store information, such as location, hours of operation, a slogan, etc. Accent lighting may also be used to advertise product information like the product name, a slogan related to the product, locations where to find the product, etc. 
   Commonly, accent lighting includes conventional light sources such as incandescent, fluorescent, or neon lights that provide the desired illumination. However, these light sources can have several drawbacks. Some of these light sources consume large amounts of electricity making them expensive to operate; particularly for outdoor signs that are illuminated for long periods of time. Conventional light sources can also generate a significant amount of heat that is not easily dissipated. In addition, conventional incandescent light sources can have a short life and/or are susceptible to damage when compared to some less conventional light sources, and as such must be inspected and replaced periodically. Neon or fluorescent lights require expensive power supplies, and typically operate at a high voltage. 
   SUMMARY OF THE INVENTION 
   The present invention provides a lighting unit including at least one elongated substrate including a plurality of light-emitting optoelectronic devices mounted thereon and an elongated housing supporting the elongated substrate. The housing also includes integrally-formed reflectors positioned adjacent the optoelectronic devices, and a translucent output panel that transmits light from the optoelectronic devices. 
   The present invention also provides a lighting unit including an elongated substrate having a plurality of optoelectronic devices mounted thereon and a first wiring harness extending from one end of the substrate and terminating with a first connector. The first wiring harness has two wires that electrically connect the plurality of optoelectronic devices with a power source. The lighting unit also includes a second wiring harness that electrically connect to the first wiring harness and the power source. The second wiring harness also has two wires that terminate with a second connector engageable with the first connector. The second wiring harness extends in a cavity or recess in the lighting unit to electrically connect an adjacent substrate or lighting unit module to the power source. 
   The present invention also provides a lighting unit including an elongated substrate having a plurality of optoelectronic devices mounted thereon, and a first wiring harness extending from one end of the substrate and terminating with a first connector. The first wiring harness electrically connects the plurality of optoelectronic devices with a power source. In one embodiment, the lighting unit also includes a second wiring harness extending from the same end of the substrate as the first wiring harness and terminating with a second connector engageable with the first connector. In another embodiment, the second wiring harness extends from an end of the substrate that is opposite to the end from which the first wiring harness extends. In both embodiments, the second wiring harness is electrically connected with the power source. The second wiring harness preferably extends along in a cavity or recess in the lighting unit to electrically connect an adjacent substrate or lighting unit module to the power source. 
   Further, the present invention provides a lighting assembly including a first lighting unit having an elongated substrate including a plurality of optoelectronic devices mounted thereon and a first wiring harness having a first connector. The first wiring harness is coupled to one end of the substrate to electrically connect the plurality of optoelectronic devices with a power source. The first lighting unit also has a second wiring harness including a second connector. The first wiring harness has either a male or female connector, and the second wiring harness has the other of the male or female connector. The second wiring harness may be coupled to the same end of the substrate as the first wiring harness to receive power from the power source, and is extendable along the substrate in a cavity of the lighting unit. The lighting assembly also includes a second lighting unit similar to the first lighting unit. The second lighting unit is positioned adjacent the first lighting unit such that the second connector of the first lighting unit engages the first connector of the second lighting unit to electrically connect the second wiring harness of the first lighting unit with the first wiring harness of the second lighting unit. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, wherein like reference numerals indicate like parts: 
       FIG. 1   a  is a cross-sectional view of a LED accent lighting unit embodying the present invention; 
       FIG. 1   b  is an enlarged, cross-sectional view of an integrally-formed reflector of the LED accent lighting unit of  FIG. 1   a;    
       FIG. 2   a  is a perspective view of multiple interconnected substrates, illustrating multiple LEDs on each substrate and insulated electrical connectors interconnecting the substrates; 
       FIG. 2   b  is an enlarged, perspective view of the electrical connector of  FIG. 2   a;    
       FIG. 3  is a perspective view of the LED accent lighting unit of  FIG. 1   a , illustrating a housing attached to a mounting strip; 
       FIG. 4   a  is a perspective view of multiple LED accent lighting units of  FIG. 1   a , illustrating multiple housings connected to a mounting strip; and 
       FIG. 4   b  is a perspective view of multiple, electrically connected LED accent lighting units of an alternate configuration. 
   

   Before at least one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limited. 
   DETAILED DESCRIPTION 
     FIG. 1   a  illustrates a cross-sectional view of an LED accent lighting unit  10 . The unit  10  includes a housing  14  extruded from plastic and cut to a pre-determined length. The housing  14  includes a slot portion  18  to insert and constrain multiple substrates  22  (see  FIG. 2   a ). One of the multiple substrates  22  is electrically connected at one end to a power source that provides DC voltage through a wiring harness  26 . Typically, either of the substrates  22  positioned at opposite ends of the unit  10  may be electrically connected to the power source via the wiring harness  26 . Each substrate  22  includes multiple wide-beam LEDs  30  that emit light over an angle of about 120 degrees. The LEDs  30  are energy efficient and as a result, large amounts of heat need not be dissipated. Each substrate  22  also includes at least one resistor  34  that provides the desired level of DC current to the LEDs  30 , which is about 20 mA. The LEDs  30  can thus be configured to operate at a low voltage, typically in the 12 to 60 volt range. 
   In one configuration of the substrate  22 , as shown in  FIG. 2   a , the resistor  34  is located toward the middle of each substrate  22 . Alternatively, the resistor  34  can be positioned toward either end of the substrate  22 . Also in the illustrated embodiment, four LEDs  30  are wired in series with the resistor  34 . This configuration provides a voltage of about 12–40 (preferably 12–24) VDC to each group of four LEDs  30 . Alternatively, more or fewer than four LEDs  30  may be wired in series with the resistor  34 . 
   As shown in  FIGS. 2   a  and  2   b , multiple substrates  22  are electrically connected to the power source by connector pins  38  that are soldered to adjacent substrates  22 . The substrates  22  include buses  40  extending along the length of the substrates  22  that electrically connect the LEDs  30  and resistors  34  to the power source when adjacent substrates  22  are electrically connected by the connector pins  38 . Insulating clips  42  support and substantially surround the connector pins  38 , and provide a mechanical connection between adjacent substrates  22  in addition to insulating the connector pins  38 . The clips  42  have nubs  43  that snap into existing apertures  46  located on the adjacent substrates  22  to interlock the adjacent substrates  22 . The clips  42  also have ramped or chamfered surfaces  45  and  47 , particularly in the region between pins  38 , to avoid interference with the LED wires and thereby aid in assembly to substrates  22 . 
   Upon interlocking two adjacent substrates  22  with an insulating clip  42  having the connector pins  38 , the connector pins  38  come into electrical and physical contact with contact plates  48 , which are exposed portions of the buses  40 . As a result, the substrate  22  that is directly electrically connected with the power source provides power to other interconnected substrates via the electrical contact between the buses  40  and the connector pins  38 . Also, the connector pins  38  may include chamfered ends to aid in the interconnection of two adjacent substrates  22 . 
   In the embodiment depicted in  FIG. 2   a , the substrates  22  are not designed to be cuttable, unlike the substrates  22   a  discussed below in connection with the second embodiment. As a result, a lighting unit comprising of several substrates  22  preferably has a first wiring harness  26  disposed at one end of the lighting unit, and a second wiring harness  27  disposed at an opposite end of the lighting unit. The first wiring harness  26  has a connector that is either a male or female connector like either connector  140  or  144  ( FIG. 4   b ). The second wiring harness will have a connector that is the other of a male or female connector like either connector  144  or  140 . Both wiring harnesses are connected to bus  40 . The first wiring harness of the end lighting unit in the assembly is connected to a power source. The second wiring harness of that same lighting unit is connected to the first wiring harness of an adjacent lighting unit in the assembly. In this way, a lighting assembly comprising multiple lighting units or modules may receive power from the power source via the bus and their respective first and second wiring harnesses. 
   Another configuration of the substrates, indicated by reference numeral  22   a , is partially illustrated in  FIG. 4   b  being utilized in lighting units  10   a . The substrates  22   a  are substantially similar to the substrates  22  of  FIG. 2   a , with like components having like reference numerals. Each substrate  22   a  is divided into multiple sections  49 , with each section  49  including two LEDs  30  wired in series with a resistor  34 . Each substrate  22   a  is cuttable, such that any number of sections  49  may be cut from the substrate  22   a  to shorten the substrate  22   a . This allows a user to custom-fit the substrate  22   a  to a user-specific application. 
   In each lighting unit  10   a , multiple substrates  22   a  may be interconnected using the same connector pins and clips (not shown in  FIG. 4   b ) as the substrates  22  of  FIG. 2   a , and power may be transferred to interconnected substrates via the buses  40  and connector pins. One of the multiple substrates  22   a  in each lighting unit  10   a  is directly electrically connected to the power source by a first wiring harness  26   a . The first wiring harness  26   a  includes two wires that are soldered or otherwise connected to the contact plates  48  of the buses  40  at one end of the substrate  22   a  to provide power to all the interconnected substrates  22   a . The first wiring harness  26   a  connects to the power source via an input connector  140  having a first configuration. The substrate  22   a  having the first wiring harness  26   a  also includes a second wiring harness  26   b  having two wires soldered or otherwise connected to the same contact plates  48  as the wires of the first wiring harness  26   a . The second wiring harness  26   b  includes an output connector  144 . This is either a male or female connector engageable with the first connector  140 . The length of the second wiring harness  26   b  allows the second wiring harness  26   b  to extend along the multiple interconnected substrates  22   a  and away from the end of the substrate  22   a  connected to the second wiring harness  26   b , in cavity  130  ( FIG. 1   a ). 
   At least one transient suppressor  50  is included in the units  10 ,  10   a  and electrically connected to one of the substrates  22 ,  22   a  within the units  10 ,  10   a . The transient suppressor  50  substantially prevents voltage spikes from damaging the LEDs  30  due to static electricity resulting from handling and other situations. As shown in  FIGS. 2   a  and  4   b , the transient suppressor  50  is shown toward the end of the substrate  22 ,  22   a  connected to the power source. Alternatively, the transient suppressor  50  can be located anywhere on any of the substrates  22 ,  22   a.    
   The substrates  22 ,  22   a  are also coated by a flexible waterproof transparent sealer for protection against the outside environment. The sealer protects the substrates  22 ,  22   a  and the LEDs  30  from the environment, while allowing the substrates  22 ,  22   a  to expand and contract with varying temperatures. 
   Since the substrates  22 ,  22   a  are also made of a fiberglass material and are relatively thin, the substrates  22 ,  22   a  include some degree of flexibility. This allows the substrates  22 ,  22   a  to be used in applications demanding the substrates  22 ,  22   a  to bend around some curved surfaces. 
   As shown in  FIGS. 1   a  and  3 , the housing  14  includes integrally-formed reflectors  54 . The reflectors  54  define the upper part of the slot portion  18  and help constrain the substrates  22 ,  22   a  within the slot portion  18 . The reflectors  54  include stems  58  projecting from opposing sides of the housing  14  that are integrally formed with opposing reflective surfaces  62 . Each reflective surface  62  includes a curved portion  66  and a straight portion  70  (most clearly shown in  FIG. 1   b ). The LEDs  30  are positioned at substantially the same level as the straight portion  70  such that the light emitted by the LEDs  30  is substantially incident on the reflective surfaces  62  above the straight portion  70 . The curved portion  66  is positioned above the straight portion  70  and reflects the light emitted by the LEDs  30 . The reflective surfaces  62  additionally diffuse the incident light. 
   As shown in  FIG. 1   a , a lens  74  including an inner surface  78  and outer surface  82  is positioned above the LEDs  30  and connected to the housing  14  via a hook and slot arrangement. The hooks  86  are integrally formed with the lens  74  of an impact-resistant acrylic. The slots  90  are integrally formed with the housing  14  and engage the hooks  86  to interconnect the lens  74  and housing  14 . The lens  74  is translucent and also acts as a diffuser for the light incident on the inner surface  78  so that the light transmitted from the outer surface  82  is diffused. As a result, a substantially uniform light is emitted from the outer surface  82  of the lens  74 . 
   As shown in  FIG. 4   a , translucent end caps  94  are coupled to the ends of the units  10 . The end caps  94  substantially cover the ends of the units  10  such that light emitted from the LEDs  30  is incident on the end caps  94  as well as the lens  74 . Since the end caps  94  are translucent, there are no dark spots shown on the surfaces of the lens  74  and end caps  94 . 
   As shown in  FIGS. 1   a  and  3 , a mounting strip  98  is fastened to a surface where the unit  10  is to be located and includes a ball-pivoting end  102  and a first locking tab  106  to interconnect to the housing  14 . The mounting strip  98  further includes a v-notch  110  disposed between the ball-pivoting end  102  and the first locking tab  106  wherein the v-notch  110  provides a guide to position the mounting strip fasteners  114  that support the unit  10 . The housing  14  has a socket end  118  to receive the ball-pivoting end  102  of the mounting strip  98  and a second locking tab  122  and guide tab  126  to engage the first locking tab  106  of the mounting strip  98 . To mount the housing  14  to the strip  98 , the socket end  118  of the housing  14  first engages the ball-pivoting end  102  of the strip  98 . The housing  14  is then pivoted such that the second locking tab  122  and guide tab  126  engage and interconnect with the first locking tab  106 . As shown in  FIGS. 3 and 4 , the mounting strip  98  can be bolted to a surface with the ball-pivoting end  102  facing upwards. Using this configuration, the weight of the housing  14  and lens  74  is supported by the ball-pivoting end  102  of the strip  98 . It should also be known that  FIG. 1   a  is also a representative cross-section of the lighting unit  10   a  and substrate  22   a.    
   As shown in  FIG. 4   a , several LED accent lighting units  10  may be positioned adjacent to each other to hide the individual wiring harnesses  26  attached to the individual units  10 . As shown in  FIGS. 1   a  and  3 , a cavity  130  is formed between the housing  14  and mounting strip  98  upon their interconnection. Wiring harnesses  26  from adjacent units  10  can be disposed in the cavity  130  to keep them hidden from view. The height of the cavity  130  may be increased as needed to accommodate the wiring harnesses  26 . The individual wiring harnesses  26  of the individual units  10  must then be electrically connected to the power source for operation. 
   As shown in  FIG. 4   b , several lighting units  10   a  utilizing the sectioned substrates  22   a  may also be positioned adjacent to each other to hide the wiring harnesses  26   a ,  26   b  attached to the individual units  10   a . However, rather than requiring each lighting unit  10   a  to directly electrically connect to the power source, the output connector  144  of the second wiring harness  26   b  of one unit  10   a  may engage the input connector  140  of the first wiring harness  26   a  of an adjacent unit  10   a  to provide power to the adjacent unit  10   a . Additional lighting units  10   a  may be electrically connected in the same way. 
   When positioned adjacent each other, the adjacent units  10 ,  10   a  will have the appearance of a continuous length rather than individual units  10 ,  10   a . To allow for expansion and contraction of the individual units  10 ,  10   a  about ¼ inch gap should exist between individual units  10 ,  10   a . The individual units  10 ,  10   a  can be manufactured between about 2 inches to typically 10 feet in length. In addition, the lighting units  10   a  utilizing the sectioned substrates  22   a  are field-cuttable such that the units  10   a  may be cut to a desired length during installation. The units  10 ,  10   a  also include a low profile such that they do not protrude high above the surface to which they are mounted. 
   In one embodiment of the present invention, the housing  14  (including the reflectors  54  and reflective surfaces  62 ), mounting strip  98 , and lens  74  are extruded of a plastic material that is dyed to match the color of the LED  30 . For example, a unit  16 ,  10   a  that emits green accent lighting can utilize green LEDs  30  in combination with a green housing  14  having green reflectors  54 . This configuration would minimize any losses during light transmission due to the surfaces  62  of the reflectors  54  having a color of the same wavelength of the incident light. If, however, the color of the surfaces  62  of the reflectors  54  does not have a wavelength similar to the incident light, then absorption occurs at the surfaces  62  of the reflectors  54 . 
   In another embodiment, the housing  14  is extruded of a plastic material with the reflectors  54  integrally formed within the housing  14 . The mounting strip  98  is also extruded from a plastic material similar in color and substance to the housing  14 . The lens  74  is extruded of a plastic material having a color of the desired accent lighting. The reflective surfaces  62  each include a white coating  134  to help maximize reflection and minimize absorption of the incident light. The coating  134  may be applied by a spinning fiber roller or by a spray nozzle. Using this configuration, white or any other color LEDs  30  can be used in combination with the colored lens  74  to achieve a desired color of accent lighting.