Abstract:
A fountain lighting system including a light engine head containing an LED light engine and a control housing containing control gear electronics includes a fixture support providing thermal separation between the light engine head and the control housing. The fixture support includes a lid with a bar extending from the edge thereof. The lid closes the control housing while the bar mounts the light engine head. An anchoring mount is also on the bar. The lid includes receptacles for receiving power, control and light engine cables with wicking barriers separating the various components provided in the lid itself. Temperature sensors in the light engine head and in the control housing send data communication to the control gear electronics to limit power to avoid thermal loading. The control gear electronics modulates the power to prevent apparent cycling. A pool lighting system provides similar features in a niche. A gap open to the niche thermally separates the light engine head from the control housing.

Description:
BACKGROUND OF THE INVENTION 
   The field of the present invention is light fixtures using LED light engines. 
   High output light fixtures have been developed for outdoor lighting applications. Such fixtures may be employed, given different configurations and levels of sealing, for ingrade architectural lighting, fountain lighting, pool lighting and the like. In each of these cases, the fixture is intended to be or may be submerged. Therefore, as a consequence, such lighting requires protection far exceeding conventional lighting systems and even elevated outdoor lighting systems. 
   When sealing and structural protection is required for outdoor lighting, issues are presented regarding heat buildup. Poor thermodynamic characteristics can dictate size and limit light output. Heat generating elements in such sealed environments can result in component damage and problems with the sealing integrity of the fixture itself. 
   Outdoor fixtures which have undertaken to overcome thermal difficulties and enhance sealing are disclosed in U.S. Pat. Nos. 5,198,962, 5,276,583, 5,408,397, 5,486,988, 5,572,873, 6,068,384, and RE34,709, the disclosures of which are incorporated herein by reference. 
   LED (light emitting diode) light engines have recently found applicability in the replacement of incandescent lamps for specific uses. Traffic lights and vehicle rear brake lights are two ubiquitous applications. LED light engines have the advantage that they can be controlled for color and intensity. Such light engines, however, are subject to performance limitations based on input electronics and temperature control. Control and monitoring of LED light engines is undertaken in the teachings of U.S. Pat. Nos. 7,119,500, 7,119,501, and 7,132,805, the disclosures of which are incorporated herein by reference. Even with such controls, the incorporation of high output LED light engines in rigorous outdoor environments remains a challenge. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to high output lighting systems which employ an LED light engine and can withstand rigorous outdoor environments. These systems are contemplated for outdoor use where sealing and thermal effects are of concern. LED light engines are sensitive to thermal conditions and can be damaged by prolonged moisture. 
   In the present invention, a light engine head including a chamber, a lens assembly closing the chamber and an LED light engine. The chamber is sealed with the lens assembly closing the chamber. A control housing includes a cavity, control gear electronics in the cavity and a power supply. Particular protection is afforded for the lighting system. 
   In a first separate aspect of the present invention, a fixture support for the lighting system includes a lid closing the cavity of the control housing. A beam rigidly extending from one edge of the lid has a light engine head attachment location which displaces the light engine head from the control housing. The fixture support thus assists in sealing of the control housing and thermally separating that control housing from the light housing head. Thermally conductive potting material may further be employed where enhanced heat transfer is needed. 
   In a second separate aspect of the present invention, isolation of the control housing is facilely accomplished through the provision of first receptacles located in the lid of the housing which closes and seals the housing. These receptacles allow for both high voltage and low voltage power and control to be potted, creating wicking barriers in an easily fabricated environment. Such a system is contemplated for such environments as ingrade lighting, fountain lighting and pool lighting. 
   In a third separate aspect of the present invention, the LED light engine is associated with a thermally conductive plate which is fixed in the chamber of the light engine head. A first temperature sensor measures the temperature of the plate at one location and is in data communication with the control gear electronics. The control gear electronics are constructed and arranged to reduce power to the LED light engine with the temperature sensor reaching a predetermined threshold temperature profile. This is to insure protection of the fixture elements. The threshold temperature profile is adjusted to compensate for the thermal drop between portions of the LED light engine and the sensor to insure protection of each LED component of the engine. This power control is undertaken responsive to the rate of change of temperature to avoid visually apparent changes in light intensity. This consideration inhibits visible cycling of light intensity from a fixture. 
   In a fourth separate aspect of the present invention the LED light engine is associated with a thermally conductive plate which is fixed in the chamber of the light engine head. A first temperature sensor measures the temperature of the plate at one location and is in data communication with the control gear electronics. The control gear electronics are constructed and arranged to reduce power to the LED light engine with the temperature sensor reaching a predetermined threshold temperature profile. This is to insure protection of the fixture elements. The threshold temperature profile is adjusted to compensate for the thermal drop between portions of the LED light engine to insure protection of each LED component of the engine. A second temperature sensor is located on the control gear electronics to similarly reduce power upon the sensor reaching a predetermined threshold temperature profile. In this way, both the chamber of the light engine head and the cavity of the control housing can be thermally protected separately. 
   In a fifth separate aspect of the present invention, an open, underwater niche receives a light engine head and a control housing with the head and housing being separated by a gap open to the niche. These elements are stacked in the niche with the chamber being between the gap and a lens assembly. The lens assembly faces outwardly of the niche. This assembly can further accommodate a mounting ring including circulation holes extending radially outwardly of the niche and mounts the light engine head. 
   In a sixth separate aspect of the present invention, combinations of the foregoing separate aspects are contemplated for further advantage. 
   Accordingly, it is a principal object of the present invention to provide a high intensity LED lighting system capable of rigorous outdoor use. Other and further objects and advantages will appear hereinafter. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a first embodiment of a lighting system illustrating the wiring thereof. 
       FIG. 2  is a perspective view of the lighting system of  FIG. 1  illustrating the electronics thereof. 
       FIG. 3  is a back perspective view of the lighting system of  FIG. 1 . 
       FIG. 4  is a perspective view of a second embodiment of a lighting system illustrating the wiring thereof. 
       FIG. 5  is a perspective view of the lighting system of  FIG. 4  illustrating the electronics thereof. 
       FIG. 6  is a back perspective view of the lighting system of  FIG. 4 . 
       FIG. 7  is a side view in cress section illustrating the lighting system of  FIG. 4  in a niche. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Turning to the drawings of the first embodiment, a fountain light fixture is illustrated. The fountain light fixture includes a light engine head  10  defined by two molded housing components  12 ,  14 . The upper and lower components  12 ,  14  are preferably both electrically and thermally conductive. The upper component  12  includes an annular ring  16  having a circular opening  18  there through. Circular and radial bars  20  are integrally formed with the upper component  12  to extend across the opening  18 . An annular mounting surface  22  extends radially outwardly from the opening  18 . Bosses  24  extending about the annular ring  18  provide for attachment to the lower molded housing component  14 . 
   The lower molded housing component  14  of the light engine head  10  also includes an annular ring  26 . The bosses  24  seat upon the annular ring  26  and fasteners  28  extend through the annular ring  26  to engage the bosses  24  and retain the upper component  12 . An annular mounting surface  30  on the lower component  14  faces the mounting surface  22  on the upper component  12 . A cylindrical ring  32  radially outwardly of the annular mounting surface  30  extends to the mounting surface  22  when assembled. 
   The mounting surfaces  22  and  30  cooperate with the cylindrical ring  32  to define an annular seat for a gasket  34 . The gasket  34  provides an interior groove  36  for receipt of a lens  38 . The gasket  34  also includes an axially extending flange  40  for proper positioning within the opening  18  of the upper component  12 . The gasket  34  is of elastomeric material and sized for an interference fit with the light engine head  10  when the upper and lower components  12 ,  14  are assembled thereabout. 
   The lens assembly including the lens  38  and gasket  34  closes and seals the chamber  42  defined within the upper and lower components  12 ,  14 . The chamber  42  has an annular shelf  44 . Cooling fins  46  are arranged on the outside of the lower component  14 . A potting cavity  48  extends downwardly from the annular mounting surface  30 . 
   Two mounting bosses  50  are axially aligned on either side of the lower component  14  to receive pins or bolts  52 . These elements  52  receive a mounting yoke  54 . The mounting yoke  54  of the light engine head  10  is pivotally mounted through the elements  52  about an axis parallel to the plane of the annular ring  26 . 
   Located within the light engine head  10  is an LED light engine  56 . This light engine  56  includes a number of LED units  58  which are preferably a mix of red, green and blue for controlled colors and blendable as white light. The LED light engine  56  is mounted on a thermally conductive plate  60 . This plate  60  is mounted to a shelf  44  defined in the lower component  14  of the light engine head  10 . The contact between the plate  60  and the shelf  44  may be enhanced by a thin film of thermally conductive grease or putty, in that position, the LED light engine  56  is directed toward the opening  18  to direct light through the lens  38 . 
   A control housing  62  is also preferably molded of electrically and thermally conductive material. The control housing  62  is open on one side, defining a mounting edge  64  with bosses  66  for receiving fasteners  68 . The opening further receives a gasket  70  for sealing of the interior as illustrated in  FIG. 3 . A cavity  72  is defined within the control housing  62 . 
   A power supply  76  is located within the cavity  72  of the control housing  62 . The power supply reduces the voltage from line voltage to 24 volts and also acts to rectify the current and shape the pulses. The power supply  76  is encased in thermally conductive polling material which is in turn fully in contact with the control housing  62  for heat transfer from the power supply  76  to the housing  62  for dissipation of heat. 
   Also located within the cavity  72  of the control housing  62  is control gear electronics  78  positioned on a circuit board  80 . The circuit hoard  80  with the control gear electronics  78  are also fully encased in thermally conductive potting material. The thermally conductive potting material is again engaged with the control housing  62  for transfer of heal to the housing for dissipation. A block of heat conductive material, such as copper, defines a heat sink  82 . the block  82  is integrated with the circuit board  80  adjacent to field effect transistors (not shown) which are a source of substantial heat. With the heat sink  82  thermally coupled with the control gear electronics, the assembly is fully potted in the thermally conductive potting material for heat transfer to the control housing  62 . The control gear electronics  78  control the LED light engine  56  according to known systems. Reference is again made to U.S. Pat. Nos. 7,119,500, 7,119,501, and 7,132,805 which are incorporated herein by reference above. 
   A fixture support, generally designated  84 , ties the light engine head  10  and the control housing  62  together and yet thermally separate and displaced from one another. The fixture support  84  includes a beam  86  with a lid  88  at one end. The beam  86  is connected to the lid  88  at one edge of the lid. The lid closes the opening in the control housing  62  with a flange  90  placed against the gasket  70  to seal the cavity  72 . 
   Two receptacles  92 ,  94  arc located on the inside of the lid  88  facing the cavity  72 . These two receptacles are each ported to the outside of the lid  88  to receive cables. The receptacles  92 ,  94  have sufficient depth to receive the cables and wires extending therefrom for forming junctions and subsequent potting. 
   The beam  86  extends rigidly from the lid  88 . A light engine head attachment  96  is located adjacent the end of the beam  86 . A tapped threaded hole forms the lighting head attachment  96 . The mounting yoke  54  of the light engine head  10  is pivotally fastened to the beam  86  by a bolt  98 . The axis of the pivotal fastening is normal to the axis of the elements  52  in order to form a gimbaled relationship. In this way, the light engine head  10  can be positioned at a wide range of angles, the locus of which approaches a hemisphere. 
   Between the light engine head attachment  96  and the lid  88 . A fixture attachment  100  opens in the opposite direction from the light engine bead attachment  96  and from the control housing  62 . The fixture attachment  100  is between the light engine head attachment  96  and the lid  88 . The fixture attachment  100  is for potential mounting to a supporting substrate. 
   A power cable  102  brings power to the lighting system. The sheath of the power cable  102  extends into the receptacle  92  in the lid  88 . Wires  104  within the sheath of the power cable  102  are then exposed with the ends of the wires  104  stripped bare. Pigtails  106  are placed on the ends of the wires  104  to join with lead wires (not shown) which run to the power supply  76 . Potting compound is then poured into and cured in the receptacle  92  to form a wicking barrier around the bare wire ends of the wires. A ferule may be placed around the end of the power cable  102  to prevent retraction and strain on the potting material within the receptacle  92 . Similarly, a control cable  108  extends through the lid  88  into the receptacle  94  in the same manner, this control cable is joined with leads (not shown) to the control gear electronics  78  with wicking barriers similarly formed. 
   A light engine cable  110  extends from the receptacle  94  and through the lid  88  to the light engine head  10 . The light engine cable  110  is similarly treated as the control cable  108  and the power cable  102  in termination within the receptacles. Lead wires (not shown) from the control gear electronics  78  are joined with the bare ends of the wires of the light engine cable  110  to drive the LED light engine  56 . The wires  112  in the sight engine cable  110  extend info the potting cavity  48  located in the light engine head  10  in a similar manner to that of the other end of the light engine cable  110  in the receptacle  94 . Leads to the LED light engine  56  are joined with these wires  112 , forming wicking barriers in the potting material found in the potting cavity  48 . Thus, the chamber  42  and the cavity  72  are completely isolated from one another. 
   A temperature sensor  114  is located on the thermally conductive plate  60  to monitor the temperature of that plate. This temperature sensor most advantageously a thermistor, is in data communication with the control gear electronics  78 . The location of the thermistor  114  is conveniently arranged. However, the system is adjusted to compensate for the thermal drop between portions of the thermally conductive plate  60  so as to anticipate overheating of the LED light engine  56  at any more vulnerable locations. 
   The control gear electronics  78  receives the data communication representing the temperature of the thermistor  114 . The electronics  78  are constructed and arranged to measure the rate of change of the data and vary the power input to the LED light engine  56  responsive to the rate of change of that temperature. With the electronics  78  sensing the LED light engine  56  approaching an overheated condition, power is reduced using techniques presented in the aforementioned control patents. Such actions are taken when the data communication reflects the reaching of a predetermined threshold temperature profile. The response is such that there is no on/off cycle or any cycling that would be visibly noticeable. 
   A second temperature sensor  118  is on and in data communication with the control gear electronics  78 . This second temperature sensor  116  also provides input for the electronics  78  to reduce power with the sensor  118  reaching a predetermined threshold temperature profile. In this way both the LED light engine  56  and the control gear electronics  78  can be protected from overheating. 
   In the embodiment of  FIGS. 4 through 7 , a light fixture is illustrated in a configuration most useful for employment in the niche of a swimming pool. Of course, other applications are contemplated.  FIG. 7  illustrates a niche  118  typical for the side of a pool. The niche  118  is open to the pool at one end and behind a mounting ring  120  which extends radially outwardly to cover the niche  116 . Circulation holes  122  allow for water within the pool to move in and out of the niche  118 . This lighting fixture associated with the niche  118  has many of the same functions as the fountain light fixture which will not be necessary to repeat here. However, the configuration does vary in notable respects which are addressed. 
   The mounting ring  120  is associated with the niche  118  in a typical manner. A hock on the mounting ring  120  engages one position of the niche while a screw at a diametrical location from the hook retains the mounting ring  120  in place. The lens  124  and mounting ring  120  provide a seal with the addition of a gasket on the front of the light engine bead  128 . For additional safety, an electro-grid  128  located between the lens  124  and the LED light engine  56  is grounded to the chamber to capture stray currents if the seal or lens  124  falls. 
   The control housing  130  is associated with the light engine head  126  directly without the need for a supporting bar or light engine cable. A threaded hole  132  in the control housing  130  and a like threaded hole  134  in the light engine head  126  receive a double threaded nipple  136 . The device is assembled by rotating the light engine head  124  on the control housing  130  to engage both components with the nipple  136 . This creates a pass through between the control housing  130  and the light engine head  126 . 
   The leads  138  of the LED light engine  56  and the wires  140  located in the control housing  130  define light engine connectors extending through the nipple  136 , into a receptacle  142  in the control housing  130  facing the lid  144  and then into one of the receptacles in the lid  144 . Potting compound is placed in the receptacle  146  found in the light engine head  124  to prevent moisture flow around the insulated light engine connectors. The assembled device may then be inverted and potting compound poured into the receptacle  146  which can form a wicking barrier at the pigtails. The light engine connectors can then be potted in the lid  144  before it is assembled with the control housing  130 . 
   In addition to the connection through the nipple  136 , the light engine head  126  and the control housing  130  are also attached by a plate  148  fastened to both the light engine head  126  and the control housing  130 . This arrangement leaves a gap between these components which is open to the niche  118 . Water in the niche then is able to flow between the components, cooling both and forming a thermal barrier. By stacking the components in this manner, the LED light engine  56  directs light outwardly of the niche  118  with the components stacked and thermally separated deeper into the niche. The entire assembly is supported at the front of the niche  118  by the mounting ring  120 . The LED light engine  56 , the power supply  76 , the control gear electronics  78  and the temperature sensors  114 ,  116  provide similar functions to that of the first embodiment. 
   Thus, LED lighting systems of great utility in underwater and wet environments are here disclosed. While embodiments and applications of this invention have been shown and described, it would be apparent to those skilled in the ad that many more modifications are possible without departing from the inventive concepts herein. The invention, therefore is not to be restricted except in the spirit of the appended claims.