Abstract:
A luminaire includes a rail, first and second pairs of wings formed at opposed edges of the rail, a pair of contacts on each one of the top and bottom surfaces of the rail, at least one LED module attachable to the rail via at least one magnetic element, such that the LED module is electrically coupled to one pair of the pairs of contacts. The rail configured to receive and power the at least one LED module on either one of the top and bottom surfaces.

Description:
RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application No. 61/728,615, filed Nov. 20, 2012, which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to field of luminaires, more specifically to the field of luminaires suitable for use with LED modules. 
     DESCRIPTION OF RELATED ART 
     Desktop luminaires are well known and have been used as a way to illuminate an area, typically the area on a desk (or table or the like). One issue with existing luminaires is that they tend to be relatively inflexible in their output. Typically about the most that can be accomplished with an existing luminaire is that it can be dimmed. Light emitting diodes (LED) based light sources have become more popular but most attempts to use LEDs have been based on attempting to package an LED bulb in a traditional luminaire. This can be accomplished but traditional luminaires were designed and intended to be used with incandescent bulbs and thus are not well optimized for use with LED-based modules. Consequentially, further improvements in lamps (and related fixtures) would be appreciated by certain individuals. 
     BRIEF SUMMARY 
     A fixture includes a rail with wings so as to provide an I-beam like shape. Powered contacts can extend along upper and lower surfaces of the rail. Modules are configured to be mated to the rail so as to be energized by the powered contacts. The modules can include a side configuration to facilitate moving of the module. The rail can be configured to provide powered contacts along a top surface and a bottom surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements and in which: 
         FIG. 1  is a perspective view of an embodiment of a lamp fixture and an LED module supported by the lamp fixture. 
         FIG. 2  is another perspective view of the embodiment depicted in  FIG. 1 . 
         FIG. 3  is an elevated side view of the embodiment depicted in  FIG. 1 . 
         FIG. 4  is another perspective view of the embodiment depicted in  FIG. 1 . 
         FIG. 5  is a perspective view of an underside of an embodiment of a rail suitable for use in a lamp fixture. 
         FIG. 6  is an elevated side view of the embodiment depicted in  FIG. 5 . 
         FIG. 7  is a simplified perspective view of the embodiment depicted in  FIG. 4 . 
         FIG. 8  is a perspective view of an embodiment of an LED module. 
         FIG. 9  is an exploded perspective view of an embodiment of an LED module. 
         FIG. 10  is a bottom view of an embodiment of an LED module 
         FIG. 11  is a perspective view of an underside of an embodiment of a housing suitable for use with an LED module. 
         FIG. 12  is an elevated side view of a cross section of an embodiment of an LED module. 
         FIG. 13  is a perspective view of a cross section of an embodiment of an LED module. 
         FIG. 14  is a schematic representation of an embodiment of a component arrangement in a lamp fixture and an LED module system. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description that follows describes exemplary embodiments and is not intended to be limited to the expressly disclosed combination(s). Therefore, unless otherwise noted, features disclosed herein may be combined together to form additional combinations that were not otherwise shown for purposes of brevity. 
       FIGS. 1-14  illustrate features of a luminaire  10  and an LED module  70  suitable for use therewith, the luminaire configured to use on a desktop. Convention luminaires often include a reflector that helps focus the light downward. As can be appreciated, the depicted LED module  70  can include an internal reflector (and/or lens) to help shape the emitted light and thus the luminaire does not need a reflector. Furthermore, due to the flexibility provided by rail  30 , the placement of the LED module  70  can be varied as desired. Furthermore, as the rail has powered contacts  34   a ,  35   a  and  34   b ,  35   b  on a top surface  36   a  and bottom surface  36   b , respectively, the LED modules  70  can be positioned so as to direct light up and/or down. This allows a wide range of potential illumination patterns. With three LED modules, for example, the system can be modified from three LED modules facing downward (to provide a high level of illumination on the supporting surface) to three LED modules facing upward so as to provide a more room-wide illumination effect. Naturally, combinations of one up, two down and two up, one down are also possible. 
     Furthermore, if different LED modules are configured to emit light with different colors then a number of interesting decorative effects are possible. This provides a luminaire with greater flexibility that previously was possible. For example, patriotic colors could be used in combination with regular lights so as to provide a luminaire that was both functional and made a statement. Other applications include light colors that are based on holidays and the like. And with the use of dual-colored lenses it would be possible to further increase the potential illumination effects. Variations in light output in each LED module can also be used to provide further variations in the illumination effect. 
     Turning to details depicted in the figures, a luminaire  10  includes a base  15  with a vertical member  20  and a power cord  17 . Conductors, not shown, can extend internally up the vertical member  20  to provide power to a rail  30 . The vertical member  20  supports the rail  30  and a first cap  50  and a second cap  60  are configured to cover up the connection between the rail  30  and the vertical member  20 . In an embodiment, a connector  68  can be provided to connect the conductors to the conductive members provided by the first cap  50 . While the vertical member extends upward from the base  15  (as the luminaire is configured so that the base can rest on a surface such as a desk or table), it should be noted that the vertical member could also extend above the rail  30  if desired (although the aesthetics of such a configuration would likely be inferior to the depicted design). Furthermore, the use of more than one vertical member is possible and the vertical member could extend downward to the rail. Thus, a suspended luminaire version is also contemplated. 
     As can be appreciated, the rail  30  includes wings  31   a ,  31   b  that are positioned on opposite sides of surfaces  36   a ,  36   b  of the respective upper channel  30   a  and lower channel  30   b . Powered contacts  34   a ,  34   b ,  35   a  and  35   b  are positioned in each channel and in an embodiment can be steel plated with a protective coating and can be adhered to the respective surface  36   a ,  36   b  with an insulating adhesive layer. Power is provided to the first and second caps  50 ,  60  and terminals supported by the caps (such as terminals  66   a , which would be provided on both the first and second caps  50 ,  60 ) are electrically connected to the powered contacts  34   a ,  34   b ,  35   a  and  35   b . As can be appreciated, an aperture  39  in the rail allows mating connectors  68  to electrically connect the first and second caps together (thus electrically connecting the powered contacts on both the upper and lower surfaces of the rail). 
     As depicted, the LED modules  70  are magnetically coupled to the rail  30 . In an embodiment, the powered contacts  34   a - 35   b  can be formed of a ferrite-based material so as to allow for magnets  98  supported by the LED module  70  to be attracted to the powered contacts  34   a - 35   b . This will allow terminals  92  supported by the LED module  70  to be electrically connected to the powered contacts  34   a - 35   b.    
     As can be appreciated, the depicted LED module  70  has a main body  72  configured for gripping. In an embodiment, the main body  72  has sides  79   a - 79   d  and each side has an upper edge  77   a - 77   d  and a lower edge  78   a - 78   d . In an embodiment, a distance A between upper edges  77   a ,  77   b  is greater than a distance B between lower edges  78   a  and  78   b . Similarly, a distance C between upper edges  77   c  and  77   d  can be greater than a distance D between lower edges  78   c  and  78   d . Thus, the sides  79   a - 79   d  can present an angled or tapered profile on all four sides. It should be noted that the particular ratio of A to B and C to D can be adjusted depending on aesthetic considerations but there is a benefit to having the surface area defined by distances B and D being less than a surface area defined by distances A and C as it helps keep the base  90  smaller. In addition, a benefit of having B less than A is that it has been determined such a configuration is useful for handling the LED module  70  as the resultant taper provides by sides  79   a ,  79   b  makes it easier to remove the LED module  70  from the rail  30 . It should be noted, however, that the depicted angle in the sides  79   a - 79   d  of the LED module was selected for aesthetic reasons and a wide range of angles can be provided. To further improve the handling characteristics, a recess  73  can be provided on sides  79   a ,  79   b . As can be appreciated, the actual shape of recess  73  was selected for aesthetic reasons and can varied as desired, thus the depicted recess  73  configuration is not intended to be limiting. 
     It should be noted that while it is desirable to have two opposing sides have angled sides to facilitate holding the module, in an alternative embodiment just one side  79   c  or  79   d  could be angled inwardly. Of course, the angle of the side might be different than what is depicted but, as can be appreciated, even having one angled side can provide noticeable assistance in aiding the removal of the LED module from the rail. Naturally, to obtain the full benefits of the improvements in handling, one of the sides that is not going to be facing the wings  31   a - 31   b  should have the angled side (e.g., side  79   c  or  79   d  in the depicted configuration). The depicted LED module  70  is rectangular in shape and that is helpful in ensuring the LED module  70  is positioned correctly in the rail. While LEDs are directional and thus don&#39;t work when facing an inverted current, the inclusion of a bridge rectifier in the LED module can help mitigate potential polarity issues. 
     The depicted LED module  70  includes a cover  71  that can function as a lens if desired and can be heat stacked to the main body  72 . The main body  72  includes an upper pocket  82  and a reflector  79  that is configured to direct light from an LED engine  100  that includes phosphor block  102  over a plurality of LEDs mounted on a substrate  105 . A base  90  attaches to the main body  72  and be secured in position with stakes  84  (that can be heat staked), although other conventional fastening systems can also be used if desired. A thermal interface  120  can then be applied to a lower side of the base  90  so as to provide thermal coupling between the LED engine  100  and the resulting rail  30  surface. It should be noted that the LED engine  100  is a chip-on-board (COB) style LED and any similar suitable configuration, including LED engine designs with remote phosphor blocks, could be used. The substrate  105  is positioned in a recess in the base  90  that includes a lower pocket  97  that, together with the upper pocket  82 , forms a magnet box  110 . The base further supports terminals  92  that are configured with a mating contact  92   a  and a tail  92   b . The terminals  92  electrically connect components  93  (and the LED engine  100 ) to the powered contacts  34   a - 35   b . As can be appreciated, the components  93  can include resistors, capacitors, controllers (including wireless controllers that are separately addressable), bridge rectifiers drivers and other known components that are useful to provide a desired energy input to the LED engine  100 . Thus, the LED module can configured to include a driver that coverts lower voltage AC to DC or it can be configured to provide constant current based on an input voltage. In an embodiment the LED engine can be attached directly to the base  90  via solder attach and in an embodiment the LED engine and the components can be mated together via a single soldering operation (e.g., by running the components through a solder oven). It should be noted that the base  90  can be formed of an LCP material with traces provided on the surface (e.g., using a laser direct structuring or LDS technology). 
     As can be appreciated from the schematic representation of  FIG. 14 , the LED engine  100  is supported on a substrate  105  (these components are typically provided as part of a COB LED) and uses the thermal interface  120  between the substrate  105  and surface  36   a  of the rail  30  to ensure there is a reliable and suitable thermal connection to the surface  36   a  (or surface  36   b  if the LED module is positioned on a bottom side) of the rail  30 . The thermal interface  120  can be a thermally conductive compressive pad that allows the magnets  98  to compresses the thermal interface  120  when the LED module  70  is placed on the rail  30  so that the thermal junction between the substrate and the surface  36   a  has a low thermal resistance. The magnets  98  also cause the terminals  92  to deflect, thus ensuring there is a good electrical connection to the powered contacts  34   a - 35   b.    
     It should be noted that one potential issue with the depicted rail design is that the number of LED modules placed on the rail might cause the thermal load to exceed the recommended design level. For example, a particular rail might be configured and sized so that it can dissipate 25 watts in a 22 C room while maintaining a temperature below 40 C. If each LED module is configured to output 6 watts, then placing 5 modules on the rail could potentially exceed the thermal dissipation capability of the rail. To avoid potential issues with thermal load, a resistor can be provided in series with the power contacts  34   a - 35   b  and the resister can be used to help limit the amount of power that is delivered to the rail by decreasing the voltage as addition modules are added (as additional current draw will increase the voltage drop provided by the resistor). In other words, the fixture  10  can be configured so that increasing the number of LED modules will decrease the amount of power used by each individual LED module, thus ensuring that the total number of watts used by the LED modules does not exceed the thermal limits of the rail. As it is difficult to perceive small drops in illumination, the resistor can be sized so that there negligible impact for some desired number of modules and the addition of additional modules will decrease the amount of light emitted by each module in a more perceptable manner. 
     The disclosure provided herein describes features in terms of preferred and exemplary embodiments thereof. Numerous other embodiments, modifications and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure.