Abstract:
An LED apparatus is provided in which at least one LED is simply and reliably mounted. LEDs are connected mechanically, electrically, and thermally within a lighting assembly. An LED comprises an emission layer on a substrate such as a circuit board. The circuit board is both an LED support and a conductor for connection to LED terminals. A frame has a cutout receiving the printed circuit board. The frame is fastenable to a heat dissipating surface. The cutout also defines cantilevered beams cut out within the surface of the frame. The cantilevered beams surround the LED to distribute force across the LED. The circuit board includes copper vias providing power to terminals on the LED. The terminals may be soldered to the power contact without the need for additional wiring.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from Provisional Patent Application Ser. No. 62/268,369 filed on Dec. 16, 2015, which is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The present subject matter relates to a light emitting diode (LED) apparatus in which an emission layer is placed on a substrate including at least one circuit cooperating with the LED emission layer, the LED apparatus interacting in a structure providing heat dissipation and light projection. 
         [0004]    Background 
         [0005]    Light emitting diodes have come into wide use due to their energy efficiency in converting electricity into light. One application comprises one or more light emitting diodes supported to a substrate. The substrate may be planar or approximately planar. An individual light emitting diode generally comprises a matrix, or array, of smaller light emitting components. This is generally referred to in the art as an array. For convenience in description, the light emitting unit comprising an array of smaller light emitting components is referred to herein as a light emitting diode (LED). 
         [0006]    The term array in the present specification is used to describe an arrangement of light emitting diodes. A number of light emitting diodes may be arranged in an array. Significant applications of LED arrays include high-bay lighting, street lighting, and canopy lighting. 
         [0007]    Many parameters must be controlled to provide for efficiency and reliability. A major concern is removal of heat produced by the LED. Heat causes significant degradation in the number of lumens produced by an LED if the heat transfer from LEDs to a heat sink or other body has not been maximized. It is necessary to be able to predict that after a given number of years, the LED will provide at least a predetermined percentage of the illumination level provided at installation. This enables a warranty to be provided for the given number of years. 
         [0008]    Another concern is reliable mechanical mounting of a single LED or multiple LEDs in an array. Reliable mechanical mounting requires substantial uniformity in the stress applied to LEDs or applied to circuit boards on which the LEDs are mounted. Non-uniform mounting pressure affects thermal conduction from an LED to another layer of an assembly. In order to retain LEDs in place at a distance from a fastener, it may be necessary to have increased pressure on LEDs close to the fastener. This can result in structural failure of the LED or a substrate over time. Connection of power to LEDs can also present a challenge. 
         [0009]    For purposes of the present description, an LED comprises a light emitting layer formed on a surface of a substrate Mounting means which maintain the substrate against a heat dissipating surface provide non-uniform pressure on the circuit board. The uneven pressure may crack the substrate. However, the crack may not occur until three months after installation and will not be readily detectable. 
         [0010]    Prior art apparatus have particular shortcomings which, as a group, have not been addressed in the art. Prior arrangements also include wiring requirements for connecting the LED to a power source which require additional steps beyond plugging an LED into a holder. Many different structures are provided for connecting power to an LED from another layer of an assembly. These structures tend to be complex. 
         [0011]    U.S. Pat. No. 9,109,787 discloses an LED and heat sink module for mounting in a lighting assembly. A mounting assembly captures LED modules between top and bottom mounting plates. Each LED is mounted to a heat conducting body in the LED assembly. The LED modules are sandwiched between two plates by screws. As the number of LEDs in the assembly increases, distance between screws increases and non-uniformity of pressure on the LED modules increases. Inordinate stress may be placed on modules closer to the screws, thus decreasing reliability. Complexity in construction is provided by the need to run discrete power leads from a power socket to a substrate supporting the LEDs. 
         [0012]    United States Patent Application Publication No. 20110063849 discloses an LED light module removably coupleable to a receiving lighting assembly. The module comprises a plurality of layers within a cylindrical housing. An LED lighting element is coupled to a thermal interface member and is configured to resiliently contact one or more thermally conductive surfaces of a receiving lighting assembly. The LED lighting element is included on a thermal interface member and must be connected to a circuit board in a different layer. The LED light module also comprises one or more resilient members configured to generate a compression force when the LED light module is installed in the receiving lighting assembly. The compression members comprise metal loops disposed in the nature of leaf springs. However, the metal loops may simply be replaced by a gasket. The LED light module further comprises one or more electrical contact members of the LED light module configured to releasably contact one or more electrical contact elements of a socket of the receiving lighting assembly. The contact comprises a leaf spring. A leaf spring is subject to formation of corrosion and creating an impedance at the contact. 
         [0013]    United States Patent Application Publication No. 20150167910 discloses a method for producing a light emitting diode arrangement. A plurality of LED modules comprises at least one radiation emitting semiconductor component on a carrier body. A separately fabricated connection carrier provides a mechanically stable and electrically conductive connection between the carrier bodies of two LED modules. LED modules must be provided in pairs. A single assembly is not provided in which a selectable number of LEDs may be included. 
         [0014]    U.S. Pat. No. 7,866,850 discloses a light fixture assembly comprising an LED sz5frfedi919whousing. Operation of the compression element from a first position to a second position generates a compression force which reduces thermal impedance between the LED assembly and a thermally-conductive housing. The LED must be connected to a power terminal block through intermediate layers, increasing difficulty in assembly and reliability of ohmic contact. 
         [0015]    United States Patent Application Publication No. 20130183779 discloses an LED module mounted on parallel conducting wires in order to connect to the LED. The LED assembly is potted. This assembly may not easily be reassembled. 
       SUMMARY 
       [0016]    Briefly stated, in accordance with the present subject matter, an LED apparatus is provided in which at least one LED is simply and reliably mounted. LEDs are connected mechanically, electrically, and thermally within a lighting assembly. For purposes of the present description, an LED comprises a light emitting layer formed on a surface of a substrate. An LED emission layer is provided on a substrate. The circuit board is both an LED support and a conductor for connection to LED terminals. In one form, a frame is provided with a cutout receiving the substrate. The frame is fastenable to a heat sink or other heat dissipating surface. The cutout also defines cantilevered beams cut out within the surface of the frame. The cantilevered beams surround the LED on opposite sides allowing substantially uniform force to be applied to the circuit board across the extent of the LED. The use of the cantilevered beams provides the added benefit of uniform pressure on each LED in an array. In an alternating current embodiment, the circuit board includes copper vias providing rectified power to terminals on the LED. The terminals may be soldered to the power contact without the need for additional wiring. The frame and the circuit board are substantially coplanar at a lower side. When the frame and the circuit board are fastened to a surface, heat transfer is maximized. 
         [0017]    The present subject matter provides desirable qualities in an LED lighting fixture, namely selectability of the number of LEDs, reliability of the LEDs over time to provide a preselected level of illumination, non-hazardous arrangements for connecting power leads to the LED, and reliable methods of maintaining a circuit board in a holder on which an LED is mounted. 
         [0018]    It is also highly desirable to provide an LED apparatus which is simple in construction and easy to manufacture from basic materials. In many applications, an LED lamp must be certified as safe, primarily by such standard bodies as Underwriters Laboratories (UL), the CE mark of the European Community, and the Canadian Standards Association (CSA). The present subject matter provides for simple and safe construction. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1A  is a perspective view including a light-projecting surface of a lighting apparatus for housing and interacting with an LED assembly according to the present subject matter; 
           [0020]      FIG. 1B  is a perspective view illustrating an opposite side of the apparatus of  FIG. 1A ; 
           [0021]      FIG. 2A  is a perspective view of the lighting apparatus of  FIG. 1A  with the diffuser removed; 
           [0022]      FIG. 2B  is a perspective view of the chamber member included in  FIG. 2A ; 
           [0023]      FIG. 2C  is a perspective view of an alternate embodiment in which an alternative form of LED apparatus is incorporated; 
           [0024]      FIG. 3  is a cross-sectional view of the lighting apparatus taken along line  3 - 3  in  FIG. 2A ; 
           [0025]      FIG. 4A  is an isometric view of an LED used in one exemplary embodiment; 
           [0026]      FIG. 4B  is an isometric view of an LED used in another exemplary embodiment; 
           [0027]      FIG. 5A  is a perspective view of an embodiment comprising a single LED; 
           [0028]      FIG. 5B  is a cross-sectional view taken along line  5 - 5  of  FIG. 5A ; 
           [0029]      FIG. 5C  is a plan view of  FIG. 5A  with an insulation layer removed; 
           [0030]      FIG. 5D  is a plan view of an alternate frame for mounting a plurality of LEDs; 
           [0031]      FIG. 6  is a plan view of the LED assembly illustrating additional features for hazardous environments; 
           [0032]      FIG. 7  is a perspective view of an LED assembly including additional circuity on a printed circuit board; 
           [0033]      FIG. 8A  is an isometric view of the circuit board seen in  FIG. 4B ; 
           [0034]      FIG. 8B  is an isometric view of the underside of the assembly of  FIG. 8A ; 
           [0035]      FIG. 9  is a perspective view of a frame for holding a plurality of LEDs; 
           [0036]      FIG. 10  is an exploded perspective view of the frame, the plurality of LEDs, and a mounting surface comprising a heat sink; and 
           [0037]      FIG. 11  is a plan view of the arrangement of  FIG. 10 . 
       
    
    
     DETAILED DESCRIPTION 
       [0038]      FIG. 1A  is a perspective view including a light-projecting surface of a lighting apparatus  1  for housing and interacting with an LED assembly according to the present subject matter.  FIG. 1B  is a perspective view illustrating an opposite side of the apparatus of  FIG. 1A .  FIG. 1A  and  FIG. 1B  are discussed together. 
         [0039]    The lighting apparatus  1  may take many different forms. Typical applications include high bay lighting, street lighting, and ceiling lighting. In the present illustration, the lighting apparatus  1  comprises a canopy light  2 . A canopy is a permanent structure comprising a roof and supporting building elements. The area underneath the canopy is at least partially open to either the elements or to the volume of an enclosed space containing the canopy. A canopy may be described as a ledge projecting horizontally from a sidewall. In a typical application, the canopy light  2  is installed onto a horizontally disposed overhang  4 . In the present description, terms such as horizontal and vertical are used to describe relative orientation of components. They do not necessarily imply any orientation of the lighting apparatus  1  with respect to the surface of the earth. 
         [0040]    The canopy light  2  comprises a housing  20  generally provided in the form of a box. The housing  20  comprises a lower surface  22 . “Lower” is used to denote that the lower surface  22  is substantially parallel to the overhang  4  rather than to denote any particular spatial disposition. The housing  20  comprises sidewalls  28 . The housing  20  further comprises a mounting plate  32  ( FIG. 1B ). To install the canopy light  2 , mounting plate  32  is fastened to the overhang  4 . The sidewalls  28  are each secured at an upward vertical end thereof to the mounting plate  32 . Fasteners  36  each extend through a sidewall  28  and are screwed into the mounting plate  32 . The housing  20  may include vents  40 . The vents  40  may comprise apertures at mating edges of the lower surface  22  and a side wall  28 . 
         [0041]    Light is projected through a diffuser  50 . The diffuser  50  may include a matrix of individual lenses  54 . Various materials may be used to make the diffuser  50 . One suitable example for industrial applications is polycarbonate resin. Residential applications may use glass. The diffuser  50  is held to the lower surface  22  by a peripheral bracket  60 . Diffuser fasteners  64  extend through the peripheral bracket  60  and are received in the lower surface  22 . 
         [0042]      FIG. 2A  is a perspective view of the lighting apparatus of  FIG. 1A  with the diffuser  50  removed.  FIG. 2B  is a perspective view of a chamber member included in the structure of  FIG. 2A .  FIGS. 2A and 2B  are discussed together.  FIG. 2C  is a perspective view of an alternate embodiment in which an alternative form of LED apparatus is incorporated. 
         [0043]    A chamber member  100  is affixed to an interior wall of the lower surface  22 . The chamber member  100  comprises a mounting surface  106  which is fastened to the interior wall of the lower surface  22 . The mounting surface  106  includes a chamber perimeter  110  surrounding an opening  120  through which light is projected. The opening  120  is substantially in registration with the diffuser  50  ( FIG. 1A ). A chamber  130  is provided for housing light-emitting elements further discussed below. In the present illustration, the chamber  130  comprises a truncated pyramid  146  extending upwardly from the mounting surface  106 . The chamber  130  includes tilted sidewalls  134  closed by a horizontally disposed lighting support surface  142 . The lighting support surface  142  is thermally conductive. Heat may be radiated from the lighting support surface  142 . Heat may escape through the vents  40 . The mounting surface  106  includes vents  108  in registration with the vents  40 . 
         [0044]    In  FIG. 2A  an LED apparatus  200  is illustrated mounted to the lighting support surface  142 . The LED apparatus includes an LED  210  mounted in a frame  220 . 
         [0045]    In the illustration of  FIG. 2C  an alternative frame  234  is provided including first and second frame portion  236  and  238  laterally displaced from each other. LEDs  240  and  242  are mounted in the frame portions  236  and  238  respectively. 
         [0046]      FIG. 3  is a cross-sectional view of the lighting apparatus taken along line  3 - 3  in  FIG. 2A . The chamber  130  is enclosed within the volume of the housing  20 . The lighting support surface  142  is displaced from an interior surface of the mounting plate  32  ( FIG. 1B ). Room is allowed for convection currents. Heat is thermally conducted from the LED apparatus  200  to the lighting support surface  142 . This heat is dissipated via convection from the lighting support surface  142 . 
         [0047]      FIG. 4A  and  FIG. 4B  are each a view of one form of LED  210 . The term “LED” is used in many different ways in the art. In the present description, the LED  210  comprises a light-emitting layer  250  mounted on a substrate  260 . The light-emitting layer  250  comprises a matrix of light-emitting components. The substrate  260  may comprise a printed circuit board. For convenience, a substrate including the printed circuit board may be referred to as a substrate when referring to the shape of the substrate and as a printed circuit board when referring to circuitry in or on the substrate  260 . The substrate  260  comprises an upper surface  262  and a lower surface  264 . A perimeter  268  of the light-emitting layer  250  is contained within a perimeter  270  of the substrate  260 . The embodiment of  FIG. 4A  is intended to have a DC power input. A positive terminal  274  and a negative terminal  276  are formed adjacent opposite corners of the substrate  260 . 
         [0048]      FIG. 4B  illustrates an alternating current embodiment of the LED  210  in the form of an LED  280 . The same reference numerals are used to denote components corresponding to components in  FIG. 4A . Circuit components  300  are mounted on the upper surface  262  of the substrate  260 . The circuit components  300  may be mounted on either side or both sides of the light-emitting layer  250 . The substrate  260  is formed with an upper surface  262  having dimensions selected to support a preselected group of circuit components  300 . AC input terminals  320  and  324  are mounted on the upper surface  262 . A rectifier circuit  310  is coupled to receive an input from the AC terminals  320  and  324  and to provide a DC output. The remaining circuitry  312  within the group of circuit components  300  is selected to perform other preselected functions. 
         [0049]    Copper vias  332  and  334  are formed in the substrate  260  located adjacent to and conducting power to the terminals  276  and  274  respectively. Circuit traces  340  and  342  conduct power from the rectifier  310  to the vias  332  and  334  respectively. In this manner, connections may be made without the need for additional wires. 
         [0050]      FIG. 5A  is a perspective view of an embodiment comprising a single LED  210 .  FIG. 5B  is a cross-sectional view taken along line  5 - 5  of  FIG. 5A .  FIG. 5C  is a plan view of  FIG. 5A .  FIG. 5A  illustrates a frame  400  maintaining the LED  210  in engagement with the lighting support surface  142  of the chamber member  100  ( FIG. 2A ). The frame  400  is fastened to the lighting support surface  142  by fasteners  404 . The fasteners  404  may comprise machine screws. Other forms of fasteners may be used. The frame  400  has a cutout  440 . As seen in  FIG. 5C , a plan view of  FIG. 5A , the cutout  440  is shaped to receive the substrate  260 . The cutout  440  is also shaped to define first and second frame portions  420  and  422  unitary with the frame  400 . The first and second frame portions  420  and  422  are positioned to be in the vertical path of the substrate  260 . As best seen in  FIG. 5B , vertical projections of the first and second frame portions  420  and  422  are in registration with portions of the substrate  260 . 
         [0051]    In order to provide support, the first and second frame portions  420  and  422  need to be resiliently mounted. A first frame portion  420  is at an inward end of a cantilevered arm  424 . “Inward” is used to denote a direction toward a center of the cutout  440 . The second portion  422  is at an inward end of a second cantilevered arm  426 . The use of the cantilevered arms  424  and  426  provides the added benefit of uniform pressure on each LED  210  in an array. Reliability of the LEDs to provide a preselected level of illumination over time is facilitated by mechanical and thermal engagement of the frame  400  with the surface  142 . As seen in  FIG. 5B  the LED package  200  ( FIG. 3 ) has a lower surface mounted for substantially uniform force against the surface  142 . Uniform force on the substrate  260  minimizes stress and mechanical failures such as cracking of the substrate  260 . 
         [0052]    Cantilevered arms  424  and  426  ( FIG. 5A ) are cut out within the surface of the frame  400 . The cantilevered arms  424  and  426  surround the LED  210  on opposite sides allowing substantially uniform force to be applied to the circuit board across the extent of the LED  210 . 
         [0053]    Electrodes  446  and  448  extend through opposite ends of the frame  400  for connection to the substrate  260  along circuit traces illustrated in  FIG. 5C . The frame  400  is coated with an insulation layer  450  ( FIG. 5B ). In  FIG. 5C  the frame  400  is shown with the insulation layer  450  removed. Connection of power to the electrodes  446  and  448  is further explained with respect to  FIG. 8A  and  FIG. 8B . 
         [0054]    In  FIG. 5B , the cantilevered arms  424  and  426  press the substrate  260  against the lighting support surface  142 . A number of factors influence the force applied by the cantilevered arms  424  and  426 . In one preferred form, the frame  400  comprises glass-epoxy printed circuit board material. Factors in determining the amount of force applied to the substrate  260  include the length and shape of the first and second cantilevered arms  424  and  426 , the thickness of the frame  400 , the material used to make the frame  400 , and the shape of the first and second connecting portions  430  and  434  ( FIG. 5A ). The angular displacement of the first and second cantilevered arms  424  and  426  is a function of the relative thicknesses of the frame  400  and the substrate  260 . 
         [0055]      FIG. 5C  is a plan view of the frame  400  with the insulating layer  450  removed. A trace  460  is connected to the electrode  446  and continues to a position in registration with the LED terminal  274 . A trace  462  is connected to the electrode  448  and continues to a position in registration with the LED terminal  276 . A solder joint  464  is formed to connect the terminal  274  to the trace  460 . A solder joint  466  is formed to connect the terminal  276  to the trace  462 . This structure allows the LED  210  ( FIG. 2A ) to be connected to a DC power supply without the need for a separate wire to connect each LED terminal  274  and  276  to a power source. Manufacture is simplified and cost is reduced. Reliability is enhanced. 
         [0056]      FIG. 5D  is a plan view of an alternative frame  458  for mounting a plurality of LEDs  210 . The frame  458  is an alternative to the frame  400 . The frame  458  is suitable for use, for example, in the lighting assembly of  FIG. 2C . A plurality of cutouts  440 , e.g., three in the present illustration, are provided. The frame  458  is rectangular, and cutouts  440  are parallel to each other. In other forms, the frame  458  may have other shapes and support differing numbers of LEDs  210 . An example is seen in  FIG. 9 , which is further discussed below. 
         [0057]      FIG. 6  is a view of the LED assembly  200  illustrating additional features useful in hazardous environments. The same reference numerals are used to denote components corresponding to those in  FIG. 4 ,  FIG. 5A ,  FIG. 5B . and  FIG. 5C . At least one shroud member  480  is provided in order to prevent sparks or other heating effects that may occur around exposed conductors. Exposed conductors in the LED assembly  200  include the solder joints at the positive terminal  274  and the negative terminal  276 . In the present illustration, a shroud member  480  is placed on the lighting support surface  142  and comprises a set of walls  482  surrounding the LED assembly  210 . The shroud member  480  is placed to prevent sparks or other heating effects from reaching the diffuser  60  ( FIG. 1 ). Consequently, the present construction will enable the user to comply with safety standards in a much more efficient manner than available with prior art apparatus. The shroud member  480  is shaped to minimally affect light issuing from the light-emitting surface  250 . 
         [0058]      FIG. 7  is a perspective view of an LED assembly  200  including additional circuity on the printed circuit board. The same reference numerals are used to denote components corresponding to those in  FIG. 4 ,  FIG. 5A ,  FIG. 5B , and  FIG. 5C . The embodiment of  FIG. 7  is suitable for use with an AC power input. The frame  400  comprises an alternative cutout  482  which accommodates the substrate  260 . The cantilevered arms  424  and  426  define a line  490  intersecting the LED  210 . The cutout  482  and the substrate  260  are disposed along a line  492  which is perpendicular to the line  490 . Separate substrate sections are disposed on opposite sides of the LED  210 . The separate substrate sections each support the circuitry  300 . 
         [0059]      FIG. 8A  is an isometric view of a DC version of the circuit board seen in  FIG. 4B .  FIG. 8B  is an isometric view of the underside of the assembly of  FIG. 8A . The substrate  260  is illustrated in registration with the cutout  440  in a juxtaposition in which the LED apparatus  210  is not pressed against the lighting support surface  142  ( FIG. 2C ). A power cable  500  includes a first conductor  502  and a second conductor  504  which are connected to the substrate  260  via terminals  274  and  276  ( FIG. 5C ) respectively. The power cable  500  is connected to a power source  524  by a plug  520 . The trace  460  of  FIG. 5C  connects the terminal  274  to the conductor  502 . The trace  462  of  FIG. 5C  connects the terminal  476  to the conductor  504 . 
         [0060]    The embodiment of  FIGS. 9-11  includes an array of LEDs  210 . A frame provides substantially equal pressure on a plurality of the LEDs  210  in a lamp assembly. Cutouts  608  are arranged substantially symmetrically in a frame  606 . When fasteners are placed to maintain the frame  606  in engagement with the surface  622 , force is evenly distributed against the LEDs  610 . Mechanical integrity and minimal stress are provided. Simplified wiring may also be provided. 
         [0061]      FIGS. 9, 10, and 11  together illustrate a lighting assembly  600  for enclosure in a housing such as the housing  24  in  FIG. 1A .  FIGS. 9, 10, and 11  are discussed together.  FIG. 9  is a perspective view of a frame  606  with apertures  604  and cutouts  608 . The apertures  604  receive fasteners. The cutouts  608  provide for structures that retain each LED  610  in a proper position for cooperatively providing lighting. Any or all of the cutouts  608  hold an LED  610  in the LED frame  606 . The frame  606  and the LEDs  610  taken together comprise an LED assembly  614 . In the present description, each combination of an LED  610  and the adjacent portion of the frame  600  is referred to as a subassembly  612  ( FIG. 11 ). The embodiment of  FIGS. 9-11  comprises components corresponding to a plurality of the LED assemblies  200  in the embodiments of  FIGS. 1-8 .  FIG. 10  is an exploded perspective view of the frame  606 , the plurality of LEDs  610 , and a mounting surface  622 , which is an upper surface of a heat sink  620 .  FIG. 11  is a plan view of the arrangement of  FIG. 10 . 
         [0062]    In the present embodiment, nine subassemblies  612  are provided. The subassemblies are referred to as  612   a  through  612   i.  In the present embodiment, the LED unit  612   a  is positioned at a center of the frame  606 . First, second, third, and fourth pairs of subassemblies  612  are provided. Pairs of subassemblies,  612   b - 612   c,    612   d - 612   e,    612   f - 612   g,  and  612   h - 612   i  are spaced equidistantly from a center of the frame  606  and are equiangularly displaced. 
         [0063]    In the present embodiment, the LED assembly  614  is mounted to the heatsink  620  comprising the mounting surface  622 , which is substantially flat, and radial fins  624 . Briefly described, the flat surface  622  absorbs heat from the LEDs  610 . The radial fins  624  radiate heat. Heat is carried away from the radial fins  624  by moving air. Air may move by convection or be propelled by a fan. The mounting surface  622  of the heatsink  620  includes a plurality of bores  626 . Each bore  626  is positioned to be in registration with an aperture  604  in the frame  606 . 
         [0064]    The cutouts  608  define openings for receiving the LEDs  610 . First and second cantilevered arms maintain each LED  610  in place in a manner similar to the embodiments of  FIGS. 1-8 . 
         [0065]    The embodiment of  FIGS. 9-11  demonstrates an unexpected way of maintaining substantially equal pressure on a plurality of the LEDs  610  in the lighting assembly  600 . The cutouts  608  are arranged substantially symmetrically. When fasteners are placed to maintain the frame  606  in engagement with the surface  622 , force is evenly distributed against the LEDs  610 . Mechanical integrity and minimal stress are provided. Simplified wiring may also be provided. 
         [0066]    In accordance with the present subject matter, an LED assembly and an LED assembly interacting with a light unit are provided in which assembly is simplified and reliability is maximized. Simplicity in assembly is facilitated by the provision of a frame that is relatively easily mounted to a surface and which conveniently receives LEDs. Connecting terminals of an LED on a circuit board to copper vias within the board minimizes steps in wiring and minimizes the presence of loose wires. The construction necessarily provides for heat dissipation. It is not necessary to optimize heat dissipation versus reliability in mechanical connection.