Abstract:
A robust LED lamp may be assembly by forming a heat sinking sandwich with two metal heat sinks positioned around the circuit board and pinned together a heat conductive element. The assembly is positioned by pressing it into a base providing electrical connections. The robust assembly is rapidly assembled, thermally effective in draining or spreading heat from the circuit board and is readily adaptable to a variety of applications lighting. The heat sink may be decorated, colored or otherwise esthetically enhanced for consumer appreciation.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to electric lamps and particularly to LED electric lamps. More particularly the invention is concerned with LED lamps with heat sinks for rapid manufacture. 
         [0004]    2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98 
         [0005]    LED lamps are being developed as exterior vehicle light sources. A frequent problem is to dispose of the excess heat while at the same time protecting the LED light source or chip. One method is to use a flexible substrate and wrap the LED support onto a heat sinking body. The flexed substrate may not be reliable in manufacture, and actual use. The flexing and positioning of the substrate offers opportunities in manufacture for error in construction. Another method is to form some or all of the base with a heat sinking element, such as a metal core or similar heat transferring element. The most desirable place for the heat sink to extend to is the exterior and open air. This leads to base structures with enclosed heat sinks or heat sinks passing through the base to the outside. This requires co-molding, or some other method of constructing the multi-component base which can be expensive. This contrasts with filamented automobile lamps with molded plastic bases with staked in lamp sources and electrical connections. There is then a need for an LED lamp structure that is robust, easy to make and capable of distributing a substantial heat flow from one or more LEDs. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    An LED lamp assembly may be made with a planar circuit board having a substantially greater length and width than thickness, defining a first major side and a second major side. At least one LED is mounted on a major side of the circuit board. A sliding electrical contact is extended on or from an end of the circuit board. Electrical circuitry is supported on the circuit board, coupling the at least one LED to the sliding electrical contact. A first heat sink having a planar face is sized and shaped to substantially span and fit side by side to a major side of the circuit board. The heat sink includes one or more recesses or openings of sufficient size and shape to mechanically accommodate any adjacent electrical components formed on the circuit board, and includes at least one recess receiving the at least one LED permitting the transmission of light from the at least one LED to the exterior of the lamp assembly. The planar side of the first heat sink is mechanically positioned to be in close thermal contact with a major side of the circuit board. The circuit board and heat sink assembly form an axially extending body having substantially greater length and width than thickness, with the sliding electrical contact extending beyond the periphery of the first heat sink to be exposed for electrical connection. A base is mechanically coupled to the circuit board and heat sink assembly, and has at least one latching face for mechanically coupling the lamp assembly in a lamp socket. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0007]      FIG. 1  shows a perspective view of a preferred embodiment of a LED Lamp Assembly. 
           [0008]      FIG. 2  shows an exploded view of a preferred embodiment of a LED Lamp Assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0009]      FIG. 1  shows a perspective view of a preferred embodiment of an LED lamp assembly  10 . The LED lamp assembly  10  is formed generally with at least one LED  12 , a circuit board  14 , a heat first sink  16 , and a base  18  and an optional second heat sink  20 . The preferred LED may be an LED enclosed in a carrier (TOPLED), or may be an open LED chip (chip on board). 
         [0010]      FIG. 2  shows an exploded view of a preferred embodiment of an LED lamp assembly  10 . The circuit board  14  is a planar circuit board  14  having a first major side  22  and a second major side  24 . The preferred circuit board  14  is made from a heat conductive material, such as aluminum coated as needed with electrically insulating layers on one or both sides. The preferred circuit board  14  has a greater length and width than thickness and has the general form of an elongated rectangle. The circuit board  14  may be one typical of LED lamps supporting electrical circuits, having a heat conductive layer, electrically insulating layers, or patterns, and electrically conductive patterns for delivering electrical power to the LEDs and or other electrical devices mounted to the circuit board. In one embodiment the circuit board  14  was about 5.7 cm long, 2.6 cm wide and 1.57 mm thick. 
         [0011]    At least one LED  12  is electrically coupled to the circuit board  14 . Preferably a plurality of LEDs  12  is mounted on both the first major side  22  and the second major side  24  of the circuit board  14  to generally face in two directions. The LEDs  12  may be LED assemblies (TOPLEDs) mounted on the circuit board  14 , or may be LED chips mounted directly on the circuit board  14  (chip on board). The preferred LEDs  12  all provide white light, but it is understood the LEDs may be of differing colors (red, blue, green, white) and the circuitry  36  may selectively illuminate individually or in combinations, the various LEDs  12  for differing purposes. For example, one set of LEDs may provide only white light, (back up lighting), an alternative set of LEDs may provide only red light (brake lighting), another set of LEDs may provide amber light for signaling or flashing functions (turn or warning) and so on. 
         [0012]    Formed on an end of the circuit board  14  is an insertable tongue  26  with at least one sliding electrical contact  28 . The sliding electrical contact  28  may be a metal pad or strip that extends axially from the edge of the circuit board  14  and should be thick enough to reliably form a sliding electrical contact  28  with a corresponding socket element to make an electrical connection to an electrical power source or any relevant signal control input. The sliding electrical contact  28  may comprise a copper trace formed on the surface of the circuit board  14 . 
         [0013]    Formed on the circuit board  14  may be electrical circuitry  36  and possibly including other related components  38  supported on the circuit board  14  and coupling the at least one LED  12  to the sliding electrical contact  28 . In one embodiment, the circuitry  36  and components  38  provided a simple voltage step down from the typical 12 volts used in most vehicles. 
         [0014]    The first heat sink  16  has a planar face that substantially abuts the first major side  22  of the circuit board  14 . The preferred first heat sink  16  is made from metal, such as copper, aluminum or others and has the general form of an elongated rectangle similar in size and shape to the circuit board  14 , albeit shorter or gapped at a base end so as to leave some or all of the tongue  26  and the sliding electrical contact  28  formed thereon exposed for electrical contact. In one embodiment the first heat sink  16  was made of aluminum and was 4.9 cm long, 2.6 cm wide and 1.74 mm thick leaving a tongue  26  of the circuit board  14  about (5.7 cm−4.9 cm=) 0.8 cm long uncovered and exposed for electrical connection. The first heat sink  16  is otherwise shaped to include one or more recesses or openings that span or fit corresponding LEDs  12  and electrical components  38  formed on the circuit board  14 . The first heat sink  16  includes at least one open recess  42  for receiving the at least one LED  12 . The open recess  42  permits the transmission of light from the at least one LED  12  to the exterior of the lamp assembly. The interior wall  54  defining the recess for the at least one LED may be shaped or provided with a reflective surface to direct light emitted from the LED in a preferred fashion, for example by having a parabola, or ellipse of revolution or similar shape with a mirrored surface. The planar side of the first heat sink  16  is mechanically positioned to be in close thermal contact with a major side of the circuit board  14 . Heat from the circuit board  14 , and heat from the at least one LED  12  is then substantially transmitted to the heat sink  16 , where it is spread over a larger area, exposed to greater radiation or cooling effects and otherwise effectively removed from the circuit board  14  and or LED  12 . The circuit board  14  and heat sink  16  form an axially extending body extending from the sliding electrical contact  28 . The sliding electrical contact  28  extends beyond the periphery of the heat sink(s)  16 ,  20  to be exposed for electrical connection. 
         [0015]    A similar second heat sink  20  may be mechanically coupled to the second major side  24  of the circuit board  14 . The second heat sink  20  has a similar planar face that substantially abuts the second major side  24  of the circuit board  14 . The first heat sink  16  and second heat sink  20  then sandwich the circuit board  14 , capturing the circuit board  14  intermediate first heat sink  16  and the second heat sink  20 . In a preferred embodiment, positioned intermediate the circuit board  14  and the first heat sink  16  is an insulating layer  50  to prevent electrical conduction from the circuit board  14  to the heat sink  16 . The intermediate insulating layer  50  may be any of the known insulating coatings formed on the face of the circuit board or the face of the heat sink  16 . Lacquers have been used. Alternatively, an intermediate sheet of electrically insulating material may be placed between the circuit board  14  and the heat sink  16  to prevent electrical conduction from the circuit board  14 &#39;s first major side  22  and the planar side of the heat sink  16 . The insulation is extended intermediate at least those regions of the circuit board  14  and the heat sink  16  that are directly opposite one another where both are electrically conductive. The preferred heat sink  16  (and  20 ) is further formed with a latch element  52  such as a snap connection adjacent the tongue  26  and the sliding electrical contact  28  portions. The latch element  52  may be shaped to fit known socket elements. In the preferred embodiment, the heat sink elements  16 ,  20  are formed with cavities or indentations that extend perpendicularly to the insertion direction of the sliding electrical contacts  28  to snap fit with a corresponding socket element. 
         [0016]    The preferred first heat sink  16  and the second heat sink  20  are mechanically coupled one to the other through or around the circuit board  14 . The first heat sink  16  and second heat sink  20  then press against the intermediate circuit board  14  for good thermal contact with the circuit board  14 . The preferred first heat sink  16  and the second heat sink  20  are riveted with rivets  46  one to the other to press against the intermediate circuit board  14 . The circuit board  14 , or the first heat sink  16  and second heat sink  20  may have other formed end features adjacent the base, and assembly tongue  26  to enhance coupling and alignment of the circuit board  14  and heat sink  16 ,  20  assembly with the base  18 . The exposed exterior surfaces of the heat sink  16 ,  20  may be modified for additional heat dispersion with ribs, fins, pins or similar feature, or may be colored or textured to aid heat radiation, improve light emission, decrease glare, decrease reflection or improve appearance (black, true color, white, silver, mirror reflective, dimpled, sand blasted, and so on). 
         [0017]    A base  18  may be mechanically coupled to the circuit board  14  and heat sink assembly. A base  18  may be made from molded plastic of sufficient heat tolerance so as to accommodate the support of the LED circuit board  14  and heat sink  16 ,  20  assembly. The preferred base  18  was integrally formed as a portion of the heat sink, providing further heat sinking capacity. The preferred base  18  has the general form of a flat plate with a wedgable end adjacent the tongue end  26  portion of the circuit board  14 , and a latching groove  52  transverse to the sliding contact  28 . The integrally formed metal base  18  portions may be shaped or positioned to be offset from direct contact with circuit board, in which case the insulation layer need not extend to or beyond the edged of the heat sink  16 ,  20 . The corresponding socket includes a slot shaped recess to receive the tongue  26  end of the circuit board  14 , and heat sink assembly  16 ,  20  such as the base portion  18 . The tongue  26  or base portion  18 , as the case may be, and the slot recess may include formed latching and aligning features to receive and mechanically couple with the circuit board  14  and heat sink  16 ,  20  assembly. In one embodiment, the circuit board  14  and heat sink  16 ,  20  assembly had a base end formed as a flat tongue, and the socket recess was correspondingly formed with a slightly larger rectangular slot to enable the snug insertion (coupling) of the circuit board  14  and heat sink  16 ,  20  assembly in the socket. The latched mounting may be sized, shaped or keyed according to differing lamp structures and purposes, so that a tail assembly lamp may be similarly constructed as is a turn signal lamp assembly, but the two lamp types are distinctly keyed to prevent confused use in actual application. 
         [0018]    While there have been shown and described what are at present considered to be the preferred embodiments of the invention, it will be apparent to those skilled in the art that various changes and modifications can be made herein without departing from the scope of the invention defined by the appended claims.