Abstract:
A device and method for retrofitting a light fixture from use with a lamp socket that employs a conventional incandescent or metal halide lamp, to use with a light emitting diode (LED)-based lamp assembly. The lamp fixture has a collar with a base and an annular outer wall extending out from the base. The LED lamp device includes a neck base having an annular outer wall having a shaped outside surface that is placed into direct surface contact with the inner surface of the annular outer wall of the collar, to establish an effective heat-transferring interface. The shaped outer surface of the neck base provides proper fitting of the LED lamp device into the lighting fixture, and provides a heat-transferring interface over substantially all of the outer surface of the neck base, to dissipate heat away from the LED module. Aluminum material provides high thermal conductivity, light weight, availability, and low cost.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Outdoor lighting has evolved over the years from the earliest use of incandescent lamps, through the use of fluorescent, high intensity discharge (HID), and mercury-vapor lamps, and more recently to light emitting diode (LED) lamps. LED lamps offer several advantages, including improved quality, performance, lifespan and cost, and their use and popularity have been growing. LED lighting also provides, and has the potential for further providing, reduced power consumption per unit lumen. 
         [0002]    One drawback of LED lighting systems is the cost and inconvenience of removing conventional, non-LED-based light fixtures and installing new light fixtures that are design and optimized for LED-based lamps. To defray this expense, attempts have been made to retrofit, or force-fit, LED lamp technology into non-LED lamp fixtures. Examples include the incorporation of LED lamps inside and on the outside surface of “bulb” style lamps, with threaded electrical connections so that the LED bulb lamp can be screwed into a conventional socket. 
         [0003]    An alternative means for retrofitting LED lamps into a conventional light fixture is to replace both the conventional bulb and the electrical socket with an LED lamp assembly which incorporates or is augmented with a suitable power and control systems for LED service. Nevertheless, such retrofitting efforts often fail to address one or more of the functional differences characteristic of LED lamps. In particular, LED lamps are sensitive to heat generated by the LED itself, and may loose efficiency unless the heat and local temperature increases are minimized. LED lamps are also well known to emit light in a lambertian distribution, whereas most conventional incandescent and fluorescent lamps emit a spherical light pattern. Positioning and controlling the light emitted from an LED requires a different technique than the light from a conventional lamp. Furthermore, typical power convertors that convert off-line (110-377V AC) to 24V, constant current to drive the LEDs, are bulky and do not conveniently install into such socket-type light fixtures. 
         [0004]    Therefore, there remains a need to provide improved and effective means for retrofitting LED lamps into conventional light fixtures, and for new light fixtures, which provide for efficient and effective power consumption and utilization of the light emitted from the LED lamps. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention relates to a device and method for retrofitting a light fixture from use with a lamp socket that employs a conventional incandescent or metal halide lamp powered by off-line voltage, to use with a light emitting diode (LED)-based lamp assembly. The conventional non-LED lamp fixture is of a type having a collar that has a base and an annular outer wall extending out from the base. The base of the lamp fixture is securable to a structure, such as a pole, canopy, or wall. The LED lamp device has an annular outer wall having a shaped outside surface that is placed into direct surface contact with the inner surface of the annular outer wall of the collar, to establish an effective heat-transferring interface between the LED lamp device and the collar, and a means for affixing an LED module comprising at least one LED. 
         [0006]    The material of construction of the LED lamp device is typically a metal or engineering plastic having a high thermal conductivity. Metals are typically selected from aluminum, copper, brass, bronze, iron and steel. Aluminum is particular attractive for its high thermal conductivity, light weight, availability, and low cost. The shaped outer surface of the LED lamp device provides proper fitting of the LED lamp assembly into the lighting fixture, and provides a heat-transferring interface over substantially the entire outer surface of the adapter sleeve, to dissipate heat away from the LED module and its power and control units. 
         [0007]    The LED lamp module includes a light board  81  to which is affixed one or a plurality of LEDs, and optionally LED power and control components. 
         [0008]    The means for affixing the LED module to the LED lamp device is generally disposed at the distal end, and typically is a recess formed in the distal end within which the LED module is positioned. Typically, a protective lens or transparent plate is positioned over the recessed LED module for protection from the environment and for personnel safety. Power wiring from the LED module to a power source is typically routed through openings in the LED lamp device and collar. 
         [0009]    The present invention also relates to the above-mentioned LED lamp device. 
         [0010]    The LED lamp device, and its use in a retrofitable retrofitting light fixture, can comprise an adapter sleeve having the annular outer wall with the shaped outside surface, and 2) a lamp head moveably affixed to the adapter sleeve that comprises a means for affixing the LED module. Typically the lamp head has an annular base portion having a proximal rim that associates with a shoulder on the annular wall of the adapter sleeve both to provide a broad contact interface for conducting heat through and away from the lamp head to the adapter sleeve, and to permit movement, typically rotation, of the lamp head with respect to the adapter sleeve, and more typically so that the LED module revolves around an axial centering line of the adapter sleeve. The LED module has a centerline disposed at an angle from the axial centering line of the adapter sleeve of from about 10° to about 70°. 
         [0011]    The LED lamp device can be configured with modular design features, such that the LED lamp device of the first embodiment can also be used as the adapter sleeve, configured with the shoulder on the annular wall so that a separate lamps head can be added for modifying the direction and distribution of the LED light, as well as the appearance of the LED lamp device itself. 
         [0012]    The present invention further relates to a method for retrofitting an existing lamp fixture to replace a threaded lamp socket with an LED-based lamp assembly, the lamp fixture having a collar having an annular wall with an inner wall surface, and a base to which the threaded lamp socket is secured for attaching the lamp fixture to the structure, and for communicating electrical power from an electrical power source to the threaded socket lamp, the method comprising the steps of: a. removing the threaded lamp socket from the collar; b. providing an LED lamp device having an annular wall having a shaped outside annular surface and an LED module; c. affixing the LED lamp device to the lamp fixture, wherein the shaped outside annular surface is placed into direct surface contact with the inner surface of the annular wall of the metallic collar, to establish a heat-transferring interface between the adapter sleeve and the collar, and d. connecting the electrical power source to the LED module. 
         [0013]    The invention also relates to the ornamental shape and design of the LED lamp device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  shows a perspective view of a light fixture having an LED lamp device with an LED light module. 
           [0015]      FIG. 2  shows a sectional view of the light fixture and LED lamp device taken through line  2 - 2  of  FIG. 1 . 
           [0016]      FIG. 3  shows an exploded view of the LED lamp device. 
           [0017]      FIG. 4  shows a perspective view of a light fixture having a second embodiment of the LED lamp device. 
           [0018]      FIG. 5  shows a perspective view of the LED lamp device of  FIG. 4  isolated from the light fixture and the LED module, showing a neck base and a lamp head. 
           [0019]      FIG. 6  shows a sectional, exploded view of the LED lamp device taken through line  6 - 6  of  FIG. 5 , showing an internal bracket and bolt for associating the neck base with the lamp head. 
           [0020]      FIG. 7  shows an exploded view of the LED lamp device of  FIG. 5 . 
           [0021]      FIG. 8  shows a partial sectional view of the LED lamp device taken through line  8 - 8  of  FIG. 5   
           [0022]      FIG. 9  is a perspective view of a first embodiment of the light device. 
           [0023]      FIG. 10  is a front and back view of the first embodiment of the light device. 
           [0024]      FIG. 11  is a right side and left side view of the first embodiment of the light device. 
           [0025]      FIG. 12  is a top view of the first embodiment of the light device. 
           [0026]      FIG. 13  is a bottom view of the first embodiment of the light device. 
           [0027]      FIG. 14  is a perspective view of a second embodiment of the light device. 
           [0028]      FIG. 15  is a front view of the second embodiment of the light device. 
           [0029]      FIG. 16  is a right side view of the second embodiment of the light device; the left side view is the mirror image. 
           [0030]      FIG. 17  is a back view of the second embodiment of the light device. 
           [0031]      FIG. 18  is a top view of the second embodiment of the light device. 
           [0032]      FIG. 19  is a bottom view of the second embodiment of the light device. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]    A typical LED-based lamp fixture is shown in  FIGS. 1 and 2 . The light fixture  1  includes a shade  2  and a collar  10 . The shade  2  has a frustoconical shade wall  6  that defines a distal rim  4  and a proximal rim  8  that associates with the collar  10 . The collar  10  has an annular outer wall  11  having an inner surface  12 . The outer wall  11  is generally a cylindrical shape, though more typically having one or more sidewall portions that taper outwardly from a proximal end  15  to the distal end. The shade  2  is typically fixed to the outer distal rim  14  of the collar  10 . 
         [0034]    As shown in  FIG. 2 , the base  17  located at the proximal end  15  of the collar has an opening  16 . The securing means is shown as an adapter  18  that extends through the opening  16  of the base  17  of the collar, and has an opening there through and a first end. The first end is secured, such as with threads, to an electrical conduit or cord (not shown) associated with the structure, such as a light pole, fence, and building wall, ceiling or roof (not shown). A nut  13  threads onto the outside threads of the adapter  18  to secure the base  17  of the collar  10  to the adapter  18  and to the structure. A collar bracket  19  is secured to the adapter  18 , using screws or equivalent means. An opening  21  passing through the collar bracket  19  and the opening in the adapter  18  provide access for electrical power wiring to within the light fixture. The collar bracket also has a pair of distally extending arms  22   a  and  22   b  disposed on opposite sides of the opening  21 , leading to respective tabs  24   a  and  24   b.    
         [0035]    The shade  2  and collar  10  are typically made of metal, such as aluminum or steel, or engineering plastic, that can efficiently conduct heat to the surrounding air, and typically have a thermal conductivity of at least 50 W/mK, or typically at least 200 W/mK. 
         [0036]    Disposed within the light fixture  1  is an LED lamp device  30 .  FIG. 3  shows the LED lamp device  30  after the shade  2  and collar  10  are removed in order to better illustrate the embodiment. The illustrated LED lamp device  30  has a neck base  31  having an annular wall  32  having a shaped outside surface  34  that is placed into direct surface contact with the inner surface  12  of the annular wall of the collar  10 , to establish a heat-transferring interface between the LED lamp device  30  and the collar  10 . The neck base  31  also has a recess  44  within which is disposed an LED module  80  that comprises an LED light board  81  to which is secured at least one LED  84 . 
         [0037]    A securement, such as a threaded bolt  28 , extends through flanges  33   a ,  33   b  to secure the LED lamp device  30  to the tabs  24   a,b  of the adapter  19 . The annular wall  32  has a proximal annular rim  36  that extends down proximate the outer wall  11  of the collar  10 . The proximal portion  35  of the outer surface  34  of the wall  32  that extends toward the rim  36  is configured and shaped to be placed into direct surface contact with the inner surface  12  of the annular wall  11  of the collar  10 , whereby a heat-transferring interface is established between the LED lamp device  30  and the collar  10 . The intimate, near continuous contacting surfaces of the annular wall  32  of the neck base  31  and annular wall  11  of the collar  10  provides effective heat transfer to dissipate the heat generated by the LED power source and controllers. The particular annular wall  32  is shown with a proximal outer surface  35  that is tapered or angled approximately between −5° and +10°, more typically between 1° and 5°, from vertical toward the centerline, though other surface taper properties can be formed or machined into the adapter sleeve to form the intimate surface contact with the inner surface of the collar. 
         [0038]    At the distal end of the neck base  31  is shown a pair of concentric, nested recesses  40  and  44 , disposed substantially centered on the centerline  100 . The outer recess  40  defines an upper annular sidewall  38  and the inner recess  44  defines a lower annular sidewall  42 . The inner recess  44  is sized to retain the LED light board  81 . In the floor of the recess  44  is an opening  70  through which pass electrical wiring for power and control of the LEDs. The opening  70  is preferably formed as an elongated slot  71  having a length and a width sufficiently sized to allow passing there through the LED light board  81 . In another embodiment of the LED lamp device  30 , the opening has at least one secondary slot  72  extending transversely from a middle portion along the length of the elongated slot  71 , that permits passage of the control wiring that extends normal to the PCB of the LED light board  81 . 
         [0039]    Typically the inner recess  44  is a circular shape, though other shapes can be used. The recess  44  can also be offset from the centerline  100  as desired. The outer recess  40  generally overlays the inner recess  44 , and retains a lens or transparent plate  82  through which the light from the LEDs  84  can emit. The lens  82  protects the LEDs and the electronics from the environment and provides personnel safety. The lens  82  is typically secured within the recess  40  with adhesive or other well known securing means. 
         [0040]    The LED light board is typically a printed circuit board (PCB) on which is mounted one or a plurality of LEDs, as is well known in the art. The circuitry for controlling and powering the LEDs can also be mounted on the PCB, or remotely. The LEDs can be of any kind and capacity. They can emit colored or white light; they can have an optic built-in with the LED or placed over the LED, or no optic; and they can have a surrounding reflector that re-directs low-angle LED light. In one suitable embodiment, the LEDs  84  are white LEDs each comprising a gallium nitride (GaN)-based light emitting semiconductor device coupled to a coating containing one or more phosphors. The GaN-based semiconductor device emits light in the blue and/or ultraviolet range, and excites the phosphor coating to produce longer wavelength light. The combined light output approximates a white output. For example, a GaN-based semiconductor device generating blue light can be combined with a yellow phosphor to produce white light. Alternatively, a GaN-based semiconductor device generating ultraviolet light can be combined with red, green, and blue phosphors in a ratio and arrangement that produces white light. In yet another suitable embodiment, colored LEDs are used, such are phosphide-based semiconductor devices emitting red or green light, in which case the LED module  80  produces light of the corresponding color. In still yet another suitable embodiment, the LED light board includes red, green, and blue LEDs distributed on the PCB in a selected pattern to produce light of a selected color using a red-green-blue (RGB) color composition arrangement. In this latter exemplary embodiment, the LED light board can be configured to emit a selectable color by selective operation of the red, green, and blue LEDs at selected optical intensities. 
         [0041]    The LED lamp device  30  typically receives an external power supply having an off-line voltage of 110-277 V, depending upon the local power system. In one embodiment, an external low voltage power system can be provided that converts the off-line voltage of 110-277 V AC from the structure to the 24V constant current required for the LED power and control components of the LED light board  81 . In another embodiment, the LED lamp device is configured for installation of an integral LED power and control module  90 , which converts off-line power directly to the low voltage constant current power required by the LEDs. The conventional drivers and controllers of LED boards are routinely powered with 24V constant current, which is supplied by separate off-line power converts which are generally bulky, elongated and ill-suited for incorporation into such conventional light fixtures. The components of the LED power and control module  90  can be assembled on a board or substrate  92  that can be secured within the neck base  31 , as shown in  FIG. 2 , with the substrate  92  inboard and in heat-conducting contact with the floor of inner recess  44 . 
         [0042]    In another embodiment of the invention, the neck base  31  containing the LED power and control module  90  can be filled with an electrical potting compound, such as epoxy to complete encase the components. The potting provides several benefits, including a water and corrosion barrier, component shock absorption, and a heat sink for dissipating and removing heat generated by the LED power and control module  90 . 
         [0043]      FIG. 3  shows a cover plate  86  having a plurality of opening that register over the LEDs  84  to allow light transmission. A spaced ring  88  is used to stand off the cover plate  86  from the LED light board  81  and to control the positioning of the edges of the openings in the cover plate  86  from the LEDs  84 . The cover plate can be made from a reflective material or have a reflective coating, or other decorative pattern, which also serves to disguise the electronic circuitry of the LED light board  80 . 
         [0044]    In another alternative embodiment, a control means for dimming the light output can be provided, either as an external control means associated with the structure, or an internal control means built into the LED lamp device with control wiring passing externally to the structure. 
         [0045]    Various types, sizes and shapes of such lamp fixtures are known, though each generally provides a collar that conventionally retains and houses, in a retrofitted lamp fixture embodiment, the threaded socket of the incandescent lamp. 
         [0046]    Another example of a lamp fixture is shown in a second embodiment of the invention. In the second embodiment shown in  FIGS. 4-7 , the LED lamp device  130  is comprised of the neck base  31  that has the shaped outside surface  34 , including a tapered proximal outside surface  35 , and a lamp head  150  that is moveably affixed to the distal end  37  of the adapter sleeve. The lamp head  150  has an annular wall  158  having an annular rim  152  that associates with a shoulder  39  on the distal end  37  of the annular wall  32  of the neck base  31 , to permit rotation of the lamp head  150  around the centering line  100  of the neck base  31 . The lamp head  150  is fixed to the neck base  31  for rotation around the centering line  100  by securement bolt  160  passing through hole  154  in the distal end  137  of the lamp head. The bolt  160  threads into securing bracket  162  mounted into the distal recess  44  of the neck base  31 . As shown in  FIG. 6 , the securing bracket  162  is affixed to the distal recess  44  with bolts. The securement bolt  160  can be loosened sufficiently to permit rotation of the lamp head  150  around the centering line  100  relative to the stationary neck base  31 , and then threaded down to fix the lamp head  150  against rotation. The lamp head  150  can therefore be rotated to provide the desired radial direction of the light emitted from the LED module. 
         [0047]    Each of the annular rim  152  of the lamp head  150  and the shoulder  39  of the neck base  31  is configured and formed to provide a wide area of overlap and interface, thereby ensuring sufficient surface area between the two parts so that heat from the LED module  80  can pass to the adapter sleeve and on to the collar  10 . Typically the interface is metal against metal, for example, aluminum against aluminum, to optimize heat transfer between the parts. 
         [0048]    The lamp head  150  has the first recess  144  formed in the distal surface to receive the LED module  80 . As shown in  FIGS. 5 and 7 , the LED module  80  is disposed offset from the centerline  100  of the lamp head  150 . The LED module  80  itself has a centerline  200  disposed at an angle θ to the axial centering line  100  of the adapter sleeve, the angle θ typically being from about 10° to about 70°. 
         [0049]    As in the last embodiment, and as seen in  FIG. 7 , a second recess  140  is disposed at the distal end of the lamp head  150 , concentric with the first recess  144  and substantially centered on the centerline  200  of the LED module  80  (similar to the recesses  40  and  44  of the first embodiment), for retaining the transparent lens  82  and LED module  80 , respectively. In the floor of the recess  144  is an opening  170  through which pass electrical wiring for power and control of the LEDs. 
         [0050]    The LED lamp device  130  has a means for preventing over-rotation of the lamp head  150  about the neck base  31  that prevents the internal wiring of the LED module  80  from tangling.  FIG. 8  shows an embodiment of an over-rotation prevention means consisting of a pair of rotation stops  74  and  76  that prevent the lamp head  150  from rotating more than 360 degrees around the neck base  31 . The first rotation stop  74  is positioned on an inside surface of the shoulder  39  of the neck base  31 , and the second rotation stop  76  is positioned on the underside of the floor of recess  144  of the lamp head  150 . Other means for preventing over-rotation of the lamp head  150  can be used which are well known in the art. 
         [0051]    The LED lamp device are typically made by casting aluminum by well known methods such as die casting, permanent mold casting or sand casting. Other metals can be used such as bronze and brass. The parts can also be formed by machining the metal stock. The parts can also be made of plastic materials that have high heat transfer values, by injection molding. 
         [0052]    In the illustrated designs illustrated in  FIGS. 9-19 , the broken lines show environment, and form no part of the claimed design. 
         [0053]    While the invention has been disclosed by reference to the details of preferred embodiments of the invention, it is to be understood that the disclosure is intended in an illustrative rather than in a limiting sense, as it is contemplated that modifications will readily occur to those skilled in the art, within the spirit of the invention and the scope of the appended claims.