Abstract:
A permanent adapter for incandescent lighting fixtures can removably receive LEDs but cannot itself be removed from the fixture.

Description:
TECHNICAL FIELD 
       [0001]    In various embodiments, the invention relates to adapters for lighting fixtures, and in particular to adapters that convert conventional fixtures to accommodate light-emitting diode (LED) lights. 
       BACKGROUND 
       [0002]    Organizations promoting energy efficiency often provide financial incentives to property owners for conversion from incandescent lighting sources to LEDs. Unfortunately, some property owners have been known to make the replacements, claim the financial incentive, and then revert to incandescent lighting; indeed, unscrupulous property owners may return the LEDs for a refund after falsely claiming the financial incentive. 
         [0003]    Some property owners leave the newly installed LEDs in place but revert to incandescent lighting when the LEDs wear out, because replacement LEDs can be relatively expensive. A permanently installed LED would solve this problem, but could not be replaced upon failure. Accordingly, there is a need for an LED adapter that permanently converts incandescent fixtures so they accept only LEDs, but allows replacement of an LED upon failure thereof. 
       SUMMARY OF THE INVENTION 
       [0004]    In various embodiments, the present invention features an adapter that, once installed in a receptacle for an incandescent lighting source, cannot be removed therefrom. This is generally achieved by surrounding at least a portion of the outer surface of the adapter with an activatable bonding agent. The adapter is installed in a conventional receptacle and the bonding agent is activated. The bonding agent thereupon adheres to the adjacent surfaces substantially permanently, thereby affixing the adapter to the conventional receptacle. The adapter generally includes an LED receptacle for removably receiving an LED. Because the adapter is affixed substantially permanently to the conventional receptacle, an incandescent light source cannot be installed therein. 
         [0005]    In addition, a power converter/limiter is also installed in the adapter to condition the A/C mains power received by the conventional receptacle into power suitable for use by the LED. The conditioned power is generally unsuitable and/or inadequate for use by an incandescent light source, and hence, it may not be feasible to install such a light source in the adapter. Therefore, once the adapter is installed in an existing receptacle, it can only receive LEDs-based lamps. 
         [0006]    Accordingly, in a first aspect, the invention relates to an adapter permanently affixable within a conventional receptacle for incandescent bulbs. In various embodiments, the adapter comprises a receptacle for an LED; an outer conductive surface receivable into the conventional receptacle for electrical coupling thereto; and a bonding agent surrounding at least a portion of the outer conductive surface and activatable to permanently retain the adapter within the conventional receptacle substantially without disrupting electrical coupling between the adapter and the conventional receptacle. (The terms LED, LED lamp, or LED module are used interchangeably herein to connote any LED-based lighting component receivable in a receptacle.) 
         [0007]    The conventional receptacle and the outer conductive surface may be threaded. Various embodiments further comprise circuitry for converting or limiting power delivered from the conventional receptacle to a power suitable for driving an LED received in the LED receptacle. 
         [0008]    In some embodiments, the bonding agent comprises or consists essentially of a solder or other metallic bonding agent. For example, the bonding agent may comprise at least one layer of foil comprising intermixed metal layers, where the solder is in contact with the foil. The solder may, for example, be activated by electricity, and may take the form of a wire. 
         [0009]    In other embodiments, the bonding agent is activatable by actinic radiation, e.g., ultraviolet or visible-light radiation. For example, the bonding agent may comprise an ultraviolet- or visible light-curable adhesive. In such cases, at least a portion of the outer conductive surface may be transparent. The adapter may, for example, be sufficiently transparent to facilitate curing of the adhesive by an external source of radiation. Alternatively, the outer conductive surface may be at least partially transparent, so that the adapter provides a substantially transparent light path to the outer conductive surface from a surface exposed when the adapter is received within the conventional receptacle. 
         [0010]    In another aspect, the invention relates to a method of permanently affixing an adapter within a conventional receptacle for incandescent bulbs. In various embodiments, the method comprises the steps of providing an adapter comprising (i) a receptacle for an LED, (ii) an outer conductive surface receivable into the conventional receptacle, and (iii) an activatable bonding agent surrounding at least a portion of the outer conductive surface; receiving the adapter in the conventional receptacle so that the outer conductive surface electrically couples to a surface of the conventional receptacle; and activating the bonding agent to permanently retain the adapter within the conventional receptacle substantially without disrupting electrical coupling between the adapter and the conventional receptacle. 
         [0011]    In some embodiments, the activatable bonding agent is solder placed substantially in contact with the outer conductive surface. The activatable bonding agent may for example, be a solder wire wrapped around the outer conductive surface substantially in contact therewith. Alternatively, the activatable bonding agent may comprise or consist of a foil comprising intermixed metal layers around the outer conductive surface; the foil may be chemically deposited or mechanically affixed. In still other embodiments, solder is placed substantially in contact with the foil. Activating the bonding agent may, for example, comprise causing flow of electricity therethrough—e.g., by exposing the bonding agent to electromagnetic radiation sufficient to induce a current in the bonding agent. Alternatively, activating the bonding agent may comprise turning on an LED received in the LED receptacle, whereby an electric current flowing through the LED also flows through the bonding agent. In still other embodiments, the adhesive is a conventional glue, e.g., an RTV (moisture cure) silicone formulation. 
         [0012]    In still other embodiments, activating the bonding agent comprises exposing it to actinic radiation, e.g., ultraviolet or visible-light radiation. For example, activating the bonding agent may comprises turning on an LED received in the LED receptacle, and exposing the bonding agent to actinic radiation from the LED. The receptacle may be configured so that it will not work—i.e., power (or sufficient power) will not be provided to the LED—unless bonding has been achieved. The bonding agent may include a visible indication of a suitable bond, or may interact with the LED to produce such a visible indication (e.g., a green light to indicate a proper bond and a red light to indicate a faulty permanent bond. 
         [0013]    In some embodiments, the receptacle includes circuitry for conditioning the voltage or limiting the power that can be drawn from the receptacle. 
         [0014]    These and other objects, along with advantages and features of the present invention herein disclosed, will become more apparent through reference to the following description, the accompanying drawings, and the claims. Furthermore, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and can exist in various combinations and permutations. As used herein, the term “substantially” means±10%, and in some embodiments, ±5%. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference to the following drawings, in which: 
           [0016]      FIG. 1  shows a cross-sectional view of an exemplary adapter. 
           [0017]      FIGS. 2A-2C  show cross-sectional views of another adapter and bonding of the adapter to a conventional receptacle for incandescent light sources. 
           [0018]      FIG. 3  shows an elevational view of another adapter using UV-curable epoxy as a bonding agent. 
           [0019]      FIG. 4  shows a cross-sectional view of an adapter received in a conventional receptacle. 
       
    
    
     DESCRIPTION 
       [0020]    In the exemplary adapter  100  shown in  FIG. 1 , an LED or LED-based lamp  102  can be received into a LED receptacle  104 . The adapter  100  can be received in a conventional receptacle  112  for light bulbs (e.g., an Edison base socket).  FIG. 1  shows a threaded portion  114  of the inner surface  116  of the conventional receptacle  112 . The outer surface  126  of adapter  100  also includes a threaded portion  128  so that adapter  100  can be screwed into the conventional receptacle  112 . It should be understood however, that an adapter having a threaded outer surface is illustrative only, and that adapters having an unthreaded surface or mating features such as pins or bumps (e.g., GU10, MR16 sockets) are within the scope of the present invention. The outer surface  126  of adapter  100  is conductive, i.e., it may comprise or consist essentially of a conductive metal or metal alloy (e.g., copper, silver, aluminum, etc.). Once received in the conventional receptacle  112 , the outer surface  126  of adapter  100  is in contact with the inner surface  116  of receptacle  112 . 
         [0021]    The adapter  100  has an electrical contact  132  that is electrically coupled to a base contact  134  of the conventional receptacle  112  when the adapter  100  is installed therein. The electrical contact  132  is electrically isolated from the outer conductive surface  126  of adapter  100 . Such isolation can be achieved by surrounding the electrical contact  132  with an insulation material (e.g., plastic, ceramic, etc.) (not shown) so that the electrical contact  132  is not in direct physical contact with the outer conductive surface  126 . Alternatively or in addition, the electrical contact  132  can include an inner conductive portion and an outer non-conductive portion for insulation. 
         [0022]      FIG. 1  also shows solder  140  that is activated, i.e., melted so that a substantially permanent bond is formed between the outer surface  126  of adapter  100  and the inner surface  116  of the receptacle  112  when the solder  140  resolidifies. As a result, receptacle  112  can no longer receive an incandescent light bulb. The LED  102 , however, can be removed from the LED receptacle  104  and replaced. The activation of solder  140  is described below with reference to  FIGS. 2A-2C . 
         [0023]    A power converter/limiter  150  may be included in the adapter  100  and, if included, is connected to the electrical contact  132  and the outer conductive surface  126  of the adapter  100 . After the adapter  100  is installed within the conventional receptacle  112 , the power converter/limiter  150  receives the electric power supplied to the conventional receptacle  112  (e.g., AC line voltage) and converts it into a type of power suitable for the operation of the LED  102  (e.g., 12 V DC), and may also limit the total power consumption to eliminate the user&#39;s ability to modify a higher-power device for installation into the adapter. The power converter/limiter  150  provides the converted and/or conditioned power to the LED  102 . The power converter/limiter  150  may, for example, be a solid-state transformer and/or a AC-DC rectifier, and may also contain a power- or current-limiting element. 
         [0024]    In some situations, a user may replace the LED  102  with a relatively inexpensive light source receivable in the adapter  100  that consumes substantially more power than the LED  102 . This would eliminate or mitigate the low-power-consumption benefits of using an LED. In order to deter such a replacement, in some embodiments the total power output by the power converter/limiter  150  is limited to a predetermined threshold (e.g., the power required by the LED  102 ). Thus, another light source requiring substantially more power may not be received in the adapter  100 . 
         [0025]    Bonding of an adapter embodiment  200  within a conventional receptacle  212  is illustrated in  FIGS. 2A-2C .  FIG. 2A  shows a portion of the outer surface  206  of the adapter  200  and the inner surface  216  of a receptacle  212 . in this embodiment, surfaces  206 ,  216  are smooth, and surface  206  is surrounded by a foil  222 . The foil may comprise or consist essentially of intermixed metal layers (e.g., layers of aluminum and nickel). The foil may be chemically deposited to the surface or mechanically applied. Solder  240  sandwiches the foil  222 , i.e., is in contact with the inner and outer surfaces,  224 ,  226  of foil  222 . Solder  240  can be applied to both sides of foil  222  using known methods such as, for example, coating or electrochemical deposition. Solder  240  can also take the form of a wire or band or a pattern of beads in contact with the surfaces  224 ,  226 . Adapter  200  can be supplied with foil  222  wrapped around its outer surface  206 . 
         [0026]      FIG. 2B  shows adapter  200  received within receptacle  212 . As a result, foil  222  and solder  240  intervene between the outer surface  206  of adapter  200  and the inner surface  216  of receptacle  212 .  FIG. 2B  shows that solder  240  is not activated (i.e., not melted and, hence, not bonded to either surface  206  or surface  216 ). Therefore, adapter  200  can be removed from the conventional receptacle  212 . 
         [0027]    As shown in  FIG. 2C , the foil  222  and solder  240  may be activated by a current flow that occurs when electricity is supplied to the conventional receptacle  212  for the first time following introduction of adapter  200  therein. Specifically, when a line voltage is applied between the inner surface  216  and the base contact  234 , the conversion circuitry converts the line voltage to power the LED, and current flows through foil  222  and solder  240 . This current flow can activate foil  222  and solder  240 . In particular, the current flow causes foil  222  to release sufficient heat to melt the solder. Releasing heat in response to current flow is an inherent property of a foil having intermixed metal layers. 
         [0028]    The solder  240  surrounding foil  222  melts and bonds with surfaces  206 ,  216  as it cools and solidifies; the foil  222  may disintegrate or dissolve into solder  240 . As a result, adapter  200  is substantially permanently affixed to the conventional receptacle  212 , and receptacle  212  can no longer receive an incandescent light bulb. 
         [0029]    The foil  222  and solder  240  can be activated alternatively or additionally by radiation of energy  242 . Radiation  242  can be provided by a source  244  of radiation positioned proximate to the surface  206  of adapter  200 . For example, source  244  can be a microwave emitter, radiating electromagnetic energy that induces Eddy currents in foil  222 , causing it to release heat and thereby activate solder  240 . The source of radiation  244  can alternatively be a laser emitter, or a separate electrical power supply. 
         [0030]    Permanent bonding agents other than solder can be employed. For example, as shown in  FIG. 3 , a UV- or visible light-curable epoxy can be used as a bonding agent. The adapter  300  has an LED receptacle  304  and a conducting outer surface  306  through which one or more windows  308  provide a line of sight. Although surface  306  is shown two rectangular windows  308 , fewer (i.e., only one) or more windows circumferentially distributed around receptacle  304 , and windows of different shapes and sizes (e.g., circle, oval, square, etc.) are within the scope of the present invention. Windows  308  can be formed by cutting out portions of surface  306  or by punching or drilling holes in surface  306 . 
         [0031]    Windows  308  may be fitted with flexible transparent panes  310 . Such panes can be formed using a material sufficiently transparent to allows passage of UV or visible light. Examples of such materials include clear plastic (e.g., polycarbonate). Transparent panes  310  are affixed within the windows  308  substantially permanently using methods such as gluing, clamping, riveting, etc. The conducting outer surface  306 , fitted with window panes  310 , can be threaded so that it may be screwed into a conventional incandescent receptacle. A layer  312  of a UV- or visible-light-curable epoxy is positioned in direct contact with the outer surface of window panes  310 . For example, window panes  310  can be coated with the curable epoxy. For a threaded adapter  300 , the epoxy may be applied as a bead in the spiral trough of the threads. 
         [0032]    The adapter  300  can be received in a conventional receptacle. Initially, the epoxy layer  312  is not bonded to, but is in contact with, the adjacent inner surface of the conventional adapter. The conductive outer surface  306  of adapter  300  is in electrical contact with the inner surface of the conventional receptacle. For example, if the epoxy is only within the trough of the adapter threads, or is applied in a spiral or striped pattern around the outer adapter surface  306 , areas of direct mechanical contact between the outer surface  306  and the inner surface of the receptacle remain (where the epoxy is not present and does not intervene). 
         [0033]    When the optical radiation emitted from an optical source  314  positioned above the LED receptacle  304  is directed inside the adapter  300 , the light propagates through the transparent windows  308  and activates—i.e., causes cross-linking of—the UV or visible light-curable epoxy layer  312 . As a result, the adapter  300  is substantially permanently bonded to the conventional receptacle, while allowing the epoxy-free portions of conductive outer surface  306  to maintain electrical contact with the inner surface of the conventional receptacle. As a result, an LED can be received in and removed from the LED receptacle  304  of adapter  300 , but the adapter itself cannot be removed. 
         [0034]    In the embodiment illustrated in  FIG. 3 , the adapter  300  is typically exposed to a source  314  before receiving an LED in the LED receptacle  304  so that the light from the source  314  can be directed, without obstruction, inside the adapter  300 . Alternatively, in the adapter embodiment  400  shown in  FIG. 4 , a UV LED  402  is received in the LED receptacle  404 . When the LED is turned on for the first time, UV radiation  420  therefrom exposes the epoxy layers  412 . Areas of the threaded portion may be fitted with flexible transparent regions  410  to permit transmission of UV radiation. 
         [0035]    Although a UV-curable epoxy may be used as a bonding agent in adapters  300 ,  400 , and a UV source used to activate the epoxy, it should be understood that any adhesive cross-linked by actinic radiation is suitable. Other examples include UV-curable acrylic or methacrylic polymers combined with a tackifying resin and a photoinitiator, 
         [0036]    Having described certain embodiments of the invention, it will be apparent to those of ordinary skill in the art that other embodiments incorporating the concepts disclosed herein may be used without departing from the spirit and scope of the invention. Accordingly, the described embodiments are to be considered in all respects as only illustrative and not restrictive.