Abstract:
An LED lamp includes a lamp housing including an aluminum alloy substantially free of silicone. An electrical circuit trace is disposed on the lamp housing. An LED is attached directly to the lamp housing and electrically connected to the electrical circuit trace. LED driver circuitry is electrically connected to the electrical circuit trace. A housing contains the LED driver circuitry. A threaded incandescent light-type electrical plug may be configured for reception into a standard incandescent light-type socket. The LED driver circuitry is electrically disposed between the electrical plug and the LED. The lamp housing may include a generally frusto-conical shape. A solder mask may be affixed over at least a portion of the electrical circuit trace. The lamp housing may be press formed. The lamp housing is in direct thermal conductive relation to the LED such that heat energy is dissipated from the LED directly to the lamp housing.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally relates to light emitting diodes (LEDs). More particularly, the present invention relates to an LED light bulb with an integrated heat sink. 
       BACKGROUND OF THE INVENTION 
       [0002]    Light emitting diodes (LEDs) have been available since the early 1960s in various forms, and are now widely applied in a variety of ways, including signs and message boards, vehicle lights, and even interior lights. The relatively high efficiency of LEDs is the primary reason for their popularity. Tremendous power savings are possible when LEDs are used to replace traditional incandescent lamps of similar luminous output. 
         [0003]    One aspect of high powered LED technology that has not been satisfactorily resolved is the removal of heat generated by the LED. LED lamps exhibit a substantial light output sensitivity to temperature, and in fact are permanently degraded by excessive temperature. Recently, very high performance LEDs have been commercialized. However, these LEDs emit a substantial amount of heat during their operation, which can permanently degrade the LED over time, resulting in a lower output and operating life. In ideal conditions, the life of the LED is 50,000-100,000 hours, however, this life can be shortened to less than 10% of the designed life due to the heat generated by these new super bright LEDs. Until recently, the higher light output was the trade-off for the shortened life due to the heat it generated. 
         [0004]    To maximize the life of LEDs a heat sink coupled to the LEDs has been increasingly used. For example, aluminum or metal core printed circuit boards (PCB) have been used. These PCBs have a dielectric layer on top of the metal surface which acts as an electrical insulator between the circuitry and the metal base. The circuit traces are then formed on top of the dielectric, and the electronic components attached thereto. There are several ways to manufacture a metal core PCB. For example, thin FR4 or fiberglass circuit board that already has the circuitry printed onto it is mounted onto a metal substrate. Another method is to print the circuitry onto the dielectric material after it has already been mounted onto the metal substrate. 
         [0005]    Due to the rise in popularity of LEDs, they are now widely used in architectural lamps and are becoming the standard in energy saving lighting applications. There are currently 500 million recessed lamps in America today and most of them have to be replaced with more efficient and eco-friendly lamps within few years. Light fixture designers and engineers are always challenged by the fact that a massive heat-sink is required to remove the heat from the LED, which is crucial to the life and the performance of the LED. 
         [0006]    Currently designers use a die-cast aluminum alloy conical shape body/housing as the heat-sink. The LEDs are assembled on a metal core PCB and then mounted on the heat-sink with thermal conductive paste. The LED driver is then placed in a plastic housing which also houses the lamp socket and the whole assembly is attached to the aluminum alloy heat-sink. 
         [0007]    However, there are several key problems with these designs. The first problem is that the aluminum alloys generally used to die cast these parts have silicone mixture in them for flow characteristics and smooth finish. Silicone causes the die cast alloy mixture to have a very low thermal conductivity ranging from 96.2 to 121 W/m-K. The thermal conductivity of non die cast aluminum alloy, which don&#39;t contain silicone in the mixture, such as extruded or rolled aluminum alloy is much higher, 167 W/m-K. This is 57% higher thermal conductivity which means that these aluminum alloys would dissipate the heat more than twice as fast compared to a die cast aluminum alloy. The second problem is that die-cast parts are expensive and consume way too much energy to produce them. They also break easily because of the silicone mixture. Another problem associated with the current designs is that the metal core PCB which has an aluminum core and it is covered with either a ceramic or polymer material as the dielectric. The dielectric material acts as a barrier for the heat to dissipate from the LEDs. Although many methods are used to make the heat dissipation better, but the fact remains that it is still an existing problem. 
         [0008]    Another problem exists in the life expectancy between the LEDs themselves and the components used to operate them. A typical light socket is running on alternating current (AC) power, whereas an LED requires direct current (DC). An AC to DC converter (or also called a driver) is used to convert the AC power to DC power. The LED driver is inside the lamp assembly. The drivers must have an isolated transformer inside the driver unit to isolate the AC from DC to protect the consumers from getting electrical shocks. These drivers also have capacitors and other electronic components that have relatively shorter life than the LEDs. The drivers have a 5 year life in general, whereas the LED cluster would last more than 100,000 hours or over 12 years. Also, the LED cluster is usually the most expensive part of the lamp. So when the driver fails, the whole lamp must be discarded. 
         [0009]    In summary the recessed lamps today that use die-cast heat-sink are expensive, have poor thermal conductivity, are heavy, require expensive tooling and use metal core PCBs that act as thermal barriers which slows heat dissipation. Also, when the LED driver fails, the whole light along with a functioning LED cluster must be discarded. Accordingly, there is a need for a LED light bulb with integrated heat sink and also a separable LED driver and cluster assembly that overcomes these drawbacks. The present invention fulfills these needs and provides other related advantages. 
       SUMMARY OF THE INVENTION 
       [0010]    The LED lamp of the present invention includes a lamp housing and an electrical circuit trace disposed on the lamp housing. An LED is attached directly to the lamp housing and electrically connected to the electrical circuit trace. The lamp housing is in direct thermal conductive relation to the LED such that heat energy is dissipated from the LED directly to the lamp housing. 
         [0011]    LED driver circuitry may be electrically connected to the electrical circuit trace. A housing may contain the LED driver circuitry. A threaded incandescent light-type electrical plug may be configured for reception into a standard incandescent light-type socket. The LED driver circuitry may be electrically disposed between the electrical plug and the LED. 
         [0012]    The lamp housing may include an aluminum alloy. The aluminum alloy may be substantially free of silicone. The lamp housing may include a generally frusto-conical shape. The lamp housing may be press formed. A solder mask may be affixed over at least a portion of the electrical circuit trace. 
         [0013]    Exemplary embodiments may include a first half of an electrical connector attached relative to the lamp housing and electrically connected to the LED. A second half of the electrical connector may be attached relative to and electrically connected to the LED driver circuitry. The first and second halves of the electrical connector are removably connected, such that various old or broken parts may be replaced with new parts. 
         [0014]    Exemplary embodiments may also include a light lens cap attached relative to the lamp housing. A lens may be disposed between the light lens cap and lamp housing. The lens may include a phosphor coating. A diffuser may be disposed within the lamp housing. The LED driver circuitry may be disposed directly on the lamp housing. 
         [0015]    In another exemplary embodiment of the present invention, an LED lamp includes a lamp housing including an aluminum alloy substantially free of silicone. An electrical circuit trace is disposed on the lamp housing. An LED is attached directly to the lamp housing and electrically connected to the electrical circuit trace. LED driver circuitry is electrically connected to the electrical circuit trace. A housing contains the LED driver circuitry. The lamp housing is in direct thermal conductive relation to the LED such that heat energy is dissipated from the LED directly to the lamp housing. 
         [0016]    A threaded incandescent light-type electrical plug may be configured for reception into a standard incandescent light-type socket. The LED driver circuitry is electrically disposed between the electrical plug and the LED. The lamp housing may include a generally frusto-conical shape. A solder mask may be affixed over at least a portion of the electrical circuit trace. The lamp housing may be press formed. 
         [0017]    Exemplary embodiments may include a first half of an electrical connector attached relative to the lamp housing and electrically connected to the LED. A second half of the electrical connector may be attached relative to and electrically connected to the LED driver circuitry. The first and second halves of the electrical connector may be removably connected. 
         [0018]    Exemplary embodiments may also include a light lens cap attached relative to the lamp housing. A lens may be disposed between the light lens cap and lamp housing. The lens may include a phosphor coating. A diffuser may be disposed within the lamp housing. The LED driver circuitry may be disposed directly on the lamp housing. 
         [0019]    In another exemplary embodiment of the present invention, a method for manufacturing an LED lamp assembly includes the steps of cutting a flat substrate into a first shape, forming electrical circuit traces on the flat substrate to establish discrete and electrically conductive paths for electrically interconnecting electronic components, the circuit traces including at least one LED landing, electrically and mechanically attaching an LED to the at least one LED landing, and press forming the flat substrate into a second shape. The flat substrate may include aluminum alloy which is substantially free of silicone. 
         [0020]    The first shape may include a generally circular shape. The second shape includes a generally conical or frusto-conical shape. The second shape includes a flat section connected to a non-planar press formed section, where the electrical circuit traces and LED are disposed along the flat section. 
         [0021]    The method may include the step of curing the electrical circuit traces. The method may include the step of applying a solder mask over at least a portion of the flat substrate and electrical circuit trace. 
         [0022]    The method may include the step of attaching a lens to one end of the second shape of the press formed substrate. The method may include the step of attaching a housing for the LED driver circuitry to an opposite end of the second shape of the press formed substrate. 
         [0023]    The method may include the step of attaching a threaded incandescent light-type electrical plug configured for reception into a standard incandescent light-type socket to a free end of the housing. The method may include the step of attaching an LED driver circuitry within the driver housing in electrical communication with the electrical plug and LED. 
         [0024]    Other features and advantages of the present invention will become apparent from the following more detailed description, when taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The accompanying drawings illustrate the invention. In such drawings: 
           [0026]      FIG. 1  is a perspective view of an exemplary recessed lamp embodying the present invention; 
           [0027]      FIG. 2  is a perspective view of the structure of  FIG. 1  being mounted into a ceiling; 
           [0028]      FIG. 3  is a perspective view of the structure of  FIG. 1  already mounted into a ceiling; 
           [0029]      FIG. 4  is an exploded sectional view of an embodiment of the structure of  FIG. 1 ; 
           [0030]      FIG. 5  is an assembled view of the structure of  FIG. 4 ; 
           [0031]      FIG. 6  is an exploded sectional view of another embodiment of the structure of  FIG. 1 ; 
           [0032]      FIG. 7  is an assembled view of the structure of  FIG. 6 ; 
           [0033]      FIG. 8  is a top view of an embodiment of surface interruptions on the inside surface of a conical-shaped housing taken along line  8 - 8  of  FIG. 4 ; 
           [0034]      FIG. 9  is a top view of another embodiment of surface interruptions on the inside surface of a conical-shaped housing taken along line  9 - 9  of  FIG. 4 ; 
           [0035]      FIG. 10  is an exploded sectional view of another embodiment of the structure of  FIG. 1 ; 
           [0036]      FIG. 11  is an assembled view of the structure of  FIG. 10 ; 
           [0037]      FIG. 12  is an enlarged sectional view of the structure of  FIG. 11  taken along line  12 - 12 ; 
           [0038]      FIG. 13  is a perspective view of another exemplary recessed lamp embodying the present invention; 
           [0039]      FIG. 14  is a top view of the structure of  FIG. 13 ; and 
           [0040]      FIG. 15  is a sectional of the structure of  FIG. 14  taken along line  15 - 15 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0041]    This disclosure fully incorporates herein the teachings of U.S. Pat. No. 7,676,915 issued on Mar. 16, 2010. 
         [0042]    As shown in the drawings for purposes of illustration, the present invention for an LED light bulb with integrated heat sink is referred to generally by the reference number  10 .  FIG. 1  is a perspective view of an exemplary recessed lamp  12  embodying the present invention. The recessed lamp  12  has a threaded lamp/light bulb cap  14  to attach the device to existing light sockets used today. The cap  14  is connected to a driver housing  16 . (It is known to those skilled in the art that the cap  14  comprises a threaded metallic outside which screws into a standard electrical light bulb socket. At the bottom of the cap  14  is an electrical contact separated by an insulator from the metallic threaded outside.) The driver housing  16  is typically plastic, but can be any other suitable material such as metal, carbon fiber, composites and the like. The conical-shaped lamp housing  18  is shown connected to the driver housing  16 . 
         [0043]      FIG. 2  is a perspective view of the structure of  FIG. 1  being mounted into a ceiling  20 .  FIG. 3  is a perspective view of the structure of  FIG. 1  already mounted into a ceiling  20 . A plastic lens  22  protects the internal parts of the recessed lamp  12 . 
         [0044]      FIG. 4  is an exploded sectional view of an embodiment of the structure of  FIG. 1  and  FIG. 5  is an assembled view of the structure of  FIG. 4 . The plastic lens  22  (light lens cap) is connected to the conical-shaped lamp housing  18 . Inside the lamp housing  18  are the LEDs  24 . Connected to the driver housing  16  is the LED driver circuitry  26 . There is an electrical connection  28  from the LED driver circuitry  26  to the cluster of LEDs  24 . There is another electrical connection  30  between the LED driver circuitry  26  and the cap  14 .  FIGS. 6 and 7  are similar to  FIGS. 4 and 5  but now have the addition of an intermediate lens  32  that now may be made from glass or plastic and may also include a phosphor coating. 
         [0045]    In these embodiments of the present invention, the lamp housing/body  18  is also a heat sink. Accordingly, the present invention discloses an integrated heat-sink lamp housing  18  or ILB (integrated lamp body)  18 . A new and improved method of manufacturing the device  10  is disclosed where the ILB  18  is made from a flat sheet of aluminum alloy with the LEDs  24  mounted directly in the center of the sheet. Then the ILB  18  is shaped into a conical shape using a press. A special press is used such that it forms the flat sheet of aluminum alloy into the conical-shape without exerting forces or stress onto the LEDs  24 . This way the LEDs can be placed upon a flat sheet of aluminum alloy using standard techniques and devices, and then the conical shape be formed thereafter. The cone-shaped ILB  18  could be shaped into different sized conical shapes depending on various factors to create a plurality of different sized and shaped lamps  12 . Then the LED driver circuitry  26  along with the cap  14  is then mounted to the bottom of the conical shaped lamp housing  18  from the back and the lens  22  is mounted to the wide section of the conical-shaped lamp housing  18 . 
         [0046]    An exemplary embodiment is hereafter discussed in more detail. For example, to build a PAR  30  lamp with an ILB  18 , a flat sheet of anodized aluminum alloy with typical 1 to 1.5 mm thickness material would be used. The specific thickness of the flat sheet is not critical, but due to the bending and shaping from the press, it is preferred to use a thickness that would be easy to work with. A circular shape of about 8-9″ inches in diameter is cut from the flat sheet. Specifically located and sized holes could also be punched on the surface of the flat sheet so that after forming the ILB  18 , the lamp socket assembly  16  along with the LED driver circuitry  26  could be mounted to it. It is also necessary to have input wire access hole on the bottom of the ILB  18 . Conductive electrical circuit traces for the LEDs  24  are then screened, sputtered or formed onto the center of the circular sheet which forms approximately a 2 inch circle. After curing the electrical traces a solder mask is applied using traditional methods and the LEDs  24  are mounted in the center of the flat sheet. Using a specially designed tooling for press forming, the flat sheet of alloy is then pressed into a desired conical shape which becomes the lamp body or ILB  18 . 
         [0047]    The cross section shapes of the ILB  18  are important to add airflow and convection for better heat dissipation. The inside surface of the ILB  18  could also be used as a circuit board and other electronic components could be mounted. This might be useful for higher wattage lamps  12  to remove the high temperature components from the driver  26  and place them inside the ILB  18  where there is better heat dissipation. 
         [0048]    There are many advantages achievable through the teaching of this disclosure. First, the recessed lamps  12  are much easier and cheaper to make. The present invention requires no metal core or any PCB, because the ILB  18  is the PCB. Also, the thermal dissipation of stock aluminum alloy is 57% better than die-cast parts. This means that the LEDs  24  will last significantly longer than current designs. Additionally, the present invention results in a lighter lamp  12  by a factor of 5. This therefore means lower shipping costs. Furthermore, expensive tooling is not required and very little energy is required to press form the ILB  18 . In various embodiments, the parts may be made to snap together through snap connections and appropriately sized and shaped features. For instance, the lens  22  can be snapped onto the lamp housing  18  at the wide end and then the driver housing  16  can be snapped onto the lamp housing  18  at the small end. The cap  14  can then snap onto the driver housing  16 . 
         [0049]      FIG. 8  is a top view of an embodiment of surface interruptions  34  on the inside surface of the conical-shaped body  18  taken along line  8 - 8  of  FIG. 4 . The surface interruptions  34  can comprise a diffuser  34 . Here, the surface interruptions/diffuser  34  is rounded.  FIG. 9  is a top view of another embodiment of surface interruptions  34  on the inside surface of a conical-shaped body  18  taken along line  9 - 9  of  FIG. 4 . Now the surface interruptions  34  are angled. The surface interruptions  34  may be formed form a separate piece attached inside the conical-shaped body  18  or may be formed as part of the conical-shaped body  18  during the press stage of manufacture. The surface interruptions  34  may be formed in a multitude of shapes and sizes by one skilled in the art. Electrical circuit traces  40  are also shown in simplified form. The circuit traces  40  may include LED landings  42  for facilitating the connection to the LEDs  24 . 
         [0050]      FIG. 10  is an exploded sectional view of another embodiment of the structure of  FIG. 1  and  FIG. 11  is an assembled view of the structure of  FIG. 10 .  FIG. 12  is an enlarged sectional view of the structure of  FIG. 11  taken along line  12 - 12 . In these embodiments, the driver housing  16  has been rotated 90 degrees such that it can fit between and connect the LEDs  24  and the cap  14  without the need for additional electrical connections  28  and  30  shown in the previous embodiments in  FIGS. 1-7 . Referring now to  FIG. 12 , the LED driver circuitry  26  electrically connects to the LEDs  24  through a metal contact cathode  36  and a metal contact anode  38 . Assembly has now been simplified as all parts can be snapped together in an extremely quick and efficient assembly process. 
         [0051]    Another advantage of the design embodied in  FIGS. 10-12  is that the AC to DC circuitry  26  can be separated from the rest of the lamp housing  18  and LEDs  24 . The lamp housing  18  and LEDs  24  can be manufactured as a stand-alone assembly. Then, the threaded light bulb cap  14 , driver housing  16  and LED driver circuitry can also be manufactured as a stand-alone assembly and UL approved just like another AC/DC adapter. The two stand-alone assemblies can then be designed to physically connect or attach to each other and at the same time electrically connect with each other.  FIG. 12  shows one embodiment where the LED driver  26  contains a male-type electrical plug and the lamp housing  18  contains a female-type electrical plug. It is to be understood by one skilled in the art that the male and female-type plugs may be reversed. Now, when either portion of the lamp  12  fails, the functioning part may be retained and reused. This lowers the overall cost of maintaining the lamp  10 ,  12 . 
         [0052]    For instance, it is likely that the LED driver circuitry  26  will fail before the LEDs  24 . A maintenance worker would unscrew the whole lamp  10 ,  12  from the electrical socket. (These sockets are commonly referred to as Edison-type sockets) Then the maintenance worker would separate the cap  14  and driver housing  16  from the lamp housing  18 . A new cap  14  and driver housing  16  can be attached to the older and yet still functioning lamp housing portion  18 . Because the LED driver circuitry  26  is cheaper than the LED cluster  24 , it is economical to replace only the broken portion. Furthermore, the two assemblies can be sold separately. For instance, a consumer can buy the converter/socket assembly and then choose the type of LED cluster or lamp housing they want to use for their specific space and lighting needs. 
         [0053]    Attaching the two stand-alone assemblies can be obtained with fasteners, screw connections, interferences fits, and a range of other methods known to those skilled in the art as this teaching is not limited to a precise form of connection. Furthermore, once the two stand-alone assemblies are attached, additional locking mechanisms may be used to insure the two assemblies do not come apart unexpectedly such as spring loaded locking mechanisms or special release features known to those skilled in the art. 
         [0054]      FIG. 13  is a perspective view of another exemplary recessed lamp  12  embodying the present invention and  FIG. 14  is a top view of the structure of  FIG. 13 .  FIG. 15  is a sectional of the structure of  FIG. 14  taken along line  15 - 15 . In these embodiments, the ILB  18  has taken an irregular rectangular shape as opposed to a conical shape. These embodiments demonstrate that a series of different shapes may be devised by one skilled in the art through the use of special manufacturing and press tooling. Any shape of a lamp housing  18  can be manufactured according to the present invention and this disclosure is not intended to limit it just to the specific forms shown and described herein. 
         [0055]    Although several embodiments have been described in detail for purposes of illustration, various modifications may be made to each without departing from the scope and spirit of the invention. Accordingly, the invention is not to be limited, except as by the appended claims.