Abstract:
According to an aspect, a connector plug( 11 ) for a lighting device ( 12 ) is provided. The connector plug comprises a fastening arrangement ( 13 ) for mechanically coupling the lighting device to the connector plug, and an electronic contact ( 15 ) arranged to transfer power to, and communicate data with the lighting device coupled to the connector plug. Further, the connector plug comprises a heat sink ( 17 ) having a heat reception interface ( 18 ) arranged to receive heat from the lighting device coupled to the connector plug and a heat dissipation interface arranged to dissipate at least some of the heat received via the heat reception interface. The present aspect is based on a concept of utilizing the connector plug for dissipating heat from the lighting device, whereby the overall heat dissipation from the lighting device increases, which promotes a longer life time of the lighting device.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally relates to the field of connector plugs for supplying power to lighting devices, such as luminaires or light modules. 
       BACKGROUND OF THE INVENTION 
       [0002]    Connector devices, such as sockets, for lighting devices, such as luminaires or lighting modules have the purpose of supporting and supply power to the lighting device. A socket comprises a fastening arrangement for mechanically coupling the lighting device to the socket and an electronic contact for supplying power to the lighting device. Correspondingly, a lighting device comprises a fastening arrangement and an electronic contact adapted to mate with the fastening arrangement and electronic contact of the socket. Normally, sockets are standardized, which allows mating lighting devices and sockets of different producers. Standard socket arrangements include e.g. screw type sockets and bi-pin type sockets. 
         [0003]    Modern lighting device technologies, such as solid state (e.g. light emitting diode, LED) based lighting devices often require cooling for promoting longer life-time of the lighting devices. Normally, lighting devices based on such technologies comprise a heat sink for the purpose of dissipation of heat from the lighting device. However, such heat sinks may sometimes not suffice to achieve acceptable heat dissipation from the lighting device, which in particular may be the case for relatively small LED-based lighting devices, such as G4 and G9 type LED-based lighting devices, having limited heat dissipation surfaces due to the small dimensions of the lighting device. 
       SUMMARY OF THE INVENTION 
       [0004]    It would be advantageous to achieve a connector device and a lighting device overcoming, or at least alleviating, the above mentioned drawbacks. In particular, it would be desirable to enable an alternative connector device for a lighting device compared to prior art techniques. Further, it would be desirable to enable a connector device for a lighting device enhancing heat dissipation from the lighting device. 
         [0005]    To better address one or more of these concerns, a connector plug and a lighting device having the features defined in the independent claims are provided. Preferable embodiments are defined in the dependent claims. 
         [0006]    Hence, according to an aspect, a connector plug for a lighting device is provided. The connector plug comprises a fastening arrangement for mechanically coupling the lighting device to the connector plug, and an electronic contact arranged to transfer power to, and communicate data with the lighting device coupled to the connector plug. Further, the connector plug comprises a heat sink having a heat reception interface arranged to receive heat from the lighting device coupled to the connector plug and a heat dissipation interface arranged to dissipate at least some of the heat received via the heat reception interface. 
         [0007]    According to a further aspect, a lighting device for coupling to a connector plug as defined in the previous aspect is provided. The lighting device has a connector port arrangement comprising a fastening arrangement for mechanically coupling the lighting device to the connector plug, and an electronic contact arranged to receive power from, and communicate data with the connector plug. Further, the connector port arrangement comprises a heat dissipation interface arranged to transfer heat generated by the lighting device to the connector plug. Hence, the connector plug may be insertable in the connector port arrangement of the lighting device. 
         [0008]    The present aspects are based on a concept of utilizing the connector plug for dissipating heat from the lighting device, whereby the overall heat dissipation from the lighting device increases, which promotes a longer life time of the lighting device. Heat generated by the lighting device (e.g. by one or more light sources and/or driving electronics of the lighting device) may be transferred via the heat dissipation interface (which also may be referred to as a heat dissipation surface) of the lighting device to the heat reception interface (which also may be referred to as a heat reception surface) of the heat sink of the connector plug. The heat is then transferred to, and dissipated by the heat dissipation interface (which also may be referred to as a heat dissipation surface) of the heat sink of the connector plug to the surroundings or to an external heat sink. The inventors have realized that, since connectors able to transfer power and data are usually relatively small in size, such connectors may advantageously be used e.g. for lighting devices of relatively small size having a limited heat dissipation area facing the surroundings. With the present aspects, the enhanced heat dissipation from the lighting device by means of the connector plug increases the overall heat dissipation area for such small size lighting devices. However, it will be appreciated that the present aspects may be applied to lighting devices of any size. 
         [0009]    According to an embodiment, the electronic contact of the connector plug and/or the electronic contact or the lighting device may be a universal serial bus (USB) type contact or a modular connector type contact. Connectors having these standard contact types are usually smaller in size compared to e.g. standard screw type sockets. However, conventional USB and modular connectors are not able to dissipate any significant amount of heat generated by the device connected to the connector, as such connectors are thermally insulated by materials such as PVC (polyvinyl chloride) and does not comprise any cooling means. With the present embodiment, heat dissipation is enhanced by the configuration of the heat sink of the connector plug, whereby the USB or modular type connector may be used for supplying power to and (optionally) communicating data with the lighting device. The USB type contact may e.g. be of any one of the USB standards: type A, type B, mini-A, mini-B, micro-A, and micro-B. The modular connector type contact may e.g. be of any one of the standards: Category 6 (CAT-6), Category 5 (CAT-5), Category 5e (CAT-5e), 10P10C, 8P8C, 6P6C, 6P4C and 4P4C. 
         [0010]    Modular connectors may also be referred to as “modular phone jack/plug”, “RJ connector,” and “Western jack/plug.” The term “modular connector” arose from its original use in a novel system of cabling designed to make telephone equipment more modular. It is common to use a registered jack number to refer to the physical connector itself. For example, the 8P8C modular connector type is often referred to as RJ45 because the Registered Jack standard of that name was an early user of 8P8C modular connectors. Conventional 8P8C modular connectors are currently used e.g. for Ethernet over twisted pair. Further, the 4P4C connector may be referred to as RJ9 or RJ22 and various 6P connectors as RJ11. 
         [0011]    According to an embodiment, the heat sink of the connector plug may comprise a material having a thermal conductivity of at least 1 W/(mK), such as metal, ceramics, silicon and/or thermal plastics, for conducting heat from the heat reception interface to the heat dissipation interface. The heat sink may e.g. comprise a solid piece of metal or a thermally insulating material with embedded metal pieces (or chips or particles). Further, the heat sink may comprise one or more heat pipes for improving cooling of the lighting device. With the present embodiment, the material of the heat sink enhances the heat dissipation from the lighting device via the connector plug. 
         [0012]    Optionally, the lighting device may comprise a heat sink adapted to absorb heat generated by the lighting device, wherein the heat dissipation interface of the lighting device may be (at least partly) formed by a portion of a surface of the heat sink of the lighting device. The heat sink of the lighting device may comprise metal for conducting heat generated by the lighting device to the heat dissipation interface of the heat sink of the lighting device. However, the heat dissipation interface of the lighting device may be a surface of any component in the lighting device able to transfer heat generated by the lighting device. For example, the heat dissipation surface of the lighting device may (additionally or alternatively) be (at least partly) formed by the electronic contact. Further, the heat dissipation interface of the lighting device may be part of a surface of an optical element (e.g. reflector, collimator, etc.) of the lighting device. 
         [0013]    According to an embodiment, the heat dissipation interface of the heat sink of the connector plug may comprise one or more fins (or wings). The fins increases the heat dissipation area, whereby cooling of the lighting device is enhanced. 
         [0014]    According to an embodiment, the heat dissipation interface of the connector plug may comprise an optical element, such as a reflector and/or a collimator, thereby adding optical functionality to the connector plug. 
         [0015]    According to an embodiment, the fastening arrangement of the connector plug may be of a positive lock type, such as of a bayonet type and/or a snap fit type. Correspondingly, the fastening arrangement of the lighting device may be of a positive lock type, such as of a bayonet type and/or a snap fit type, preferably adapted to mate with the fastening arrangement of the connector plug. The present embodiment is advantageous in that the fastening arrangements are more rigid, e.g. compared to the friction fastening mechanism of standard USB connectors, and reduces the risk of unintended separation of the connector plug and the lighting device. For example, the present fastening arrangements may allow suspending the lighting device in the connector plug. 
         [0016]    According to an embodiment, the heat sink is formed as a sleeve. This provides for a simple solution for an improved heat transfer between the lighting device and the connector plug. In a further embodiment the sleeve is covered by a cover layer. The cover layer may provide for improved handling of the connector plug and/or protect a user from contacting the potentially hot or warm sleeve of the heat sink directly. 
         [0017]    According to an embodiment, the connector plug may further comprise driving electronics for driving the lighting device. Hence, at least a part of the driving electronics for driving the lighting device may not necessarily be located in the lighting device, but instead in the connector plug. The present embodiment allows a more stripped (less complex) design of the lighting device. Further, it may be advantageous to separate the driving electronics from the light source of the lighting device, since driving electronics are typically rather sensitive to heat and most of the heat produced in the lighting device is generated by the light source. The driving electronics may e.g. comprise a circuit for controlling a light source of the lighting device. Optionally, other features related to the lighting device may be located in the connector plug, such as sensors, dimming circuits etc. 
         [0018]    According to an embodiment, the connector plug may further comprise a cable arranged to be electrically connected to the electronic contact, wherein the cable may be arranged to transfer power and data. Further, the cable and the fastening arrangement (such as the dimensions and the rigidity of the cable and the fastening arrangement) may be adapted for suspending the lighting device. Hence, the cable used for supplying the power and data may additionally be used for suspension of the lighting device, e.g. in a ceiling. Further, the cable may comprise electromagnetic interference (EMI) shielding, which may comprise twined metal strings, which may function as an additional heat sink of the connector plug. 
         [0019]    According to an embodiment, the lighting device may further comprise at least one solid state light source, such as one or more light emitting diodes (LEDs). Solid state light sources typically put a higher demand on cooling of the lighting device for achieving acceptable life times compared to traditional incandescent light sources. Solid state light sources normally generate less heat than incandescent light sources, but the heat generated by solid state light sources may not dissipated by means of radiation (as is the case with incandescent light sources) but in general only by means of conduction and convection. With the present embodiment, heat dissipation from the lighting device is increased by means of the connector plug. 
         [0020]    According to an embodiment, a lighting system may be provided. The lighting system may comprise a connector plug as defined in any one of the preceding embodiments and a lighting device as defined in any one of the preceding embodiments, the lighting device being adapted for connection to the connector plug. 
         [0021]    According to an embodiment, the heat reception interface of the connector plug may be arranged to be in direct (physical) contact with the heat dissipation interface of the lighting device, whereby the heat transfer from the lighting device to the connector plug is enhanced, which in turn improves cooling of the lighting device. For example, the locations and surface structures of the heat dissipation interface of the lighting device and of the heat reception interface of the connector plug may be adapted to mate with each other so as to provide physical contact. 
         [0022]    It is noted that embodiments of the invention relates to all possible combinations of features recited in the claims. Those skilled in the art realize that different features of the present invention can be combined to create embodiments other than those described in the following. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    These and other aspects will be described in more detail with reference to the appended drawings. 
           [0024]      FIG. 1  shows a lighting system of a lighting device and a connector plug according to an embodiment. 
           [0025]      FIG. 2  shows a lighting system of a lighting device and a connector plug according to another embodiment. 
           [0026]      FIG. 3  shows a lighting system of a lighting device and a connector plug according to yet another embodiment. 
           [0027]      FIG. 4  shows a lighting system of a plurality of lighting devices and a connector plug according to yet another embodiment. 
           [0028]      FIG. 5  shows a lighting system of a lighting device and a connector plug according to yet another embodiment. 
           [0029]      FIG. 6  shows a connector plug according to an embodiment. 
           [0030]      FIG. 7  shows a cross-section of the connector plug shown in  FIG. 6 . 
           [0031]      FIG. 8  shows a lighting system of a lighting device suspended by means of the connector plug shown in  FIG. 6 . 
           [0032]    All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the embodiments, wherein other parts may be omitted or merely suggested. Like reference numerals refer to like elements throughout the specification. Parts being obscured by other parts in the drawings are illustrated with dashed lines. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]    A lighting system according to an embodiment will be described with reference to  FIG. 1 .  FIG. 1  shows a lighting system  1  comprising a lighting device  12 , such as a luminaire  12  or a lighting module, and a connector plug  11  for supplying power and (optionally) data to the lighting device  12 . For example, data may be transmitted to the lighting device  12  via the connector plug  11  for controlling the lighting device  12 . Further, data may be transmitted from the lighting device  12  via the connector port, e.g. for retrieving operation information regarding the lighting device  12 . In the present example, the connector plug  11  is a universal serial bus (USB) type connector plug and the lighting device comprises a USB connector port  14  adapted to receive the connector plug  11 . The lighting device  12  may e.g. be a bulb type lighting device  12 . The connector plug  11  comprises a fastening arrangement  13  adapted to mate with a fastening arrangement of the lighting device  12  (not shown) so as to mechanically couple (fixate) the lighting device  12  to the connector plug  11 . In the present example, the fastening arrangements of the lighting device  12  and the connector plug comprise a (preferably releasable) snap fit connection. For example, the snap fit connection may comprise a hook arranged at one of the connector plug  11  and the lighting device  12  and a recess adapted to mate with the hook arranged at the other one of the connector plug  11  and the lighting device  12  (such as within the connector port  14  of the lighting device  12 ) so as to lock the mechanical connection between the lighting device  12  and the connector plug  11 . 
         [0034]    The connector plug  11  further comprises a heat sink  17 , the outer surface of which forms a heat dissipation interface towards the surroundings. Further, the heat sink  17  has a heat reception interface  18  in thermal connection with the heat dissipation interface, e.g. via a core of the heat sink  17 . The heat sink  17  may comprise metal for providing a thermal path from the heat reception interface  18  to the heat dissipation interface. The lighting device  12  comprises a heat dissipation interface  19  able to dissipate heat generated by the lighting device  12 . Such heat may e.g. be generated by one or more light sources, such as light emitting diodes (LEDs), and/or by driving electronics comprised in the lighting device  12 . The heat dissipation interface  19  of the lighting device  12  may e.g. be a surface portion of the port  14  and/or of a heat sink of the lighting device  12  (not shown), or of any component of the lighting device  12  able to absorb (and conduct) heat generated in the lighting device  12 . The heat dissipation interface  19  of the lighting device  12  and the heat reception interface  18  of the connector plug  11  are arranged such that heat can be transferred there between when the lighting device  12  is coupled to the connector plug  11 . Preferably, the heat dissipation interface  19  of the lighting device  12  and the heat reception interface  18  of the connector plug  11  are adapted to mate with each other so as to provide physical contact there between when the lighting device  12  is coupled to the connector plug  11 . 
         [0035]    The connector plug  11  may further comprise an electronic contact  15  and a cable  16  electrically connected to the electronic contact  16  for supplying power and communicating data. The lighting device  12  may comprise a corresponding electronic contact (not shown), e.g. arranged in the port  14 , adapted to mate with the electronic contact  15  of the connector plug  11  when the connector plug  11  is coupled to the lighting device  12 . In the present example, the electronic contacts of the lighting device  12  and the connector plug  11  are USB type electronic contacts. 
         [0036]    The connector plug  11  may be coupled to the lighting device  12  by inserting the connector plug  11  in the port  14  such that the fastening arrangements (the snap fit mechanism) locks the lighting device  12  to the connector plug  11 , whereby the electronic contacts of the lighting device  12  and the connector plug  11  are electrically connected and power (and optionally data) can be supplied to the lighting device  12 . When the lighting device  12  is switched on, heat is generated by the components of the lighting device  12 , which heat is conducted via the heat dissipation interface  19  of the lighting device  12  to the heat reception interface  18  of the connector plug  11  and then further on, via the core of the heat sink  17  of the connector plug  11 , to the heat dissipation interface (i.e. the outer surface of the heat sink  17 ) of the connector plug  11 , where the heat is dissipated to the surroundings. In this way, the lighting device  12  is cooled by means of the connector plug  11 . 
         [0037]    Optionally, the driving electronics for driving the lighting device  12  and/or other components for controlling/monitoring the lighting device  12  (such as sensors) may be arranged in the connector plug  12 . 
         [0038]    In the following, systems and devices according to further embodiments will be described, which in principle may be similarly configured as the system and devices described with reference to  FIG. 1  and operate according to the same principle as described above. It will be appreciated that various features described in the following may be combined with the embodiment described with reference to  FIG. 1  and with each other. 
         [0039]      FIG. 2  shows a lighting system  2  comprising a lighting device  22  and a connector plug  21  according to an embodiment. In the present example, an electronic contact  25  of the connector plug  21  and a corresponding electronic contact of the lighting device  22  are mini USB contacts, which in particular may be advantageous for small lighting devices. In the present example, the lighting device  22  may be G4 or G9 type lighting device having a port  24  compatible for connection to the mini USB type connector plug  21 . Further, a heat sink of the connector plug  21  may be formed as a sleeve  27  having a heat reception interface  28  on the inside of the sleeve adapted to surround a portion  29  of the lighting device  22 . The outer surface of the portion  29  of the lighting device  22  surrounded by the sleeve  27  may form (at least a part of) a heat dissipation interface  28  of the lighting device  22 . Further, the outside (or outer surface) of the sleeve  27  may form a heat dissipating interface of the connector plug  22 . The sleeve  27  may extend substantially from the end portion of the connector plug  22  and along a portion of a cable  26  of the connector plug  21 . In the present example, heat generated by the lighting device  22  is conducted to, and dissipated by the sleeve  27  of the connector plug  21 . 
         [0040]      FIG. 3  shows a lighting system  3  comprising a lighting device  32  and a connector plug  31  according to another embodiment. In the present example, a heat sink of the connector plug  31  may comprise a flexible metal foil  37 , optionally covered by a flexible cover  33 . The foil  37  (and the cover  33 ) may be pleated (or curved) and extend along a portion of the cable  36 . In the present example, the connector plug  31  is a USB connector plug having a USB electronic contact  35  and the lighting device  32  may comprise a corresponding USB connector port  34 . A thermal interface between the connector plug  31  and the lighting device  32  may e.g. be provided at the USB plug/port interface. Further, in the present example, the lighting device  32  comprises an LED  38  (e.g. of the type L2) and a light guide  39  optically coupled to the LED  38 . The light guide  39  may comprise a light out coupling surface for emitting light propagating in the light guide  39 . In the present example, heat generated by the lighting device  31  is conducted via the plug/port interface and then dissipated via the metal foil  37  and the cover  33  of the connector plug  31 . 
         [0041]      FIG. 4  shows a lighting system  4  comprising a plurality of lighting devices  42  connected to a connector plug  41  according to an embodiment. The lighting devices  42  may comprise light guides, as shown in  FIG. 4 , and/or other optical elements, such as reflectors, total internal reflection (TIR) collimators and/or lenses (not shown). In the present example, the connector plug  41  may comprise a heat sink block  47 , preferably made of metal. The block  47  may comprise one or more fins  48  for increasing the heat dissipation area of the connector plug  41 . The connector plug  41  may comprise one or more ports  44  in which the electronic contacts of the connector plug  41  may be arranged. The lighting devices  42  may comprise plugs  43  for insertion in the ports  44 . The electronic contacts of the lighting devices  42  may be arranged in the plugs  43 . In the present example, heat generated by the lighting devices  42  is dissipated via the block  47  of the connector plug  41 . 
         [0042]      FIG. 5  shows a lighting system  5  comprising a lighting device  52  and a connector plug  51  according to another embodiment. In the present example, the connector plug  51  comprises a Category 5 (CAT-5) contact having a snap fit fastening arrangement  53  and the lighting device  52  comprises a corresponding CAT-5 connector port  56  with a mating snap fit fastening arrangement. The lighting device  52  further comprises a heat sink forming a projecting portion  55  of the lighting device  52  and having a heat dissipation interface  59 . The connector plug  51  comprise a heat sink  57  having a heat reception surface  54  arranged such that the heat dissipation interface  59  of the lighting device  52  overlaps and directly contacts the heat reception interface  54  of the connector plug  51  when the lighting device  52  is coupled to the connector plug  51 . In the present example, the heat sink  57  of the connector plug  51  may comprise one or more fins (or wings)  58 , the surface of which forms (at least a part of) the heat dissipation interface of the connector plug  51 . Optionally, the fins  58  may be pleated. When the connector plug  51  is coupled to the lighting device  52 , the heat dissipation interface  59  slides in place over the heat reception interface  54  of the connector plug  51 , whereby heat is enabled to be conducted from the lighting device  52  to the connector plug  51  and subsequently dissipated via the fins  58 . 
         [0043]      FIG. 6  is a perspective view of a connector plug  61  according to an embodiment.  FIG. 7  shows a cross-section of the connector plug  61  shown in  FIG. 6 . In the present example, the connector plug  61  is a CAT-x type contact, such as a CAT-5 or CAT-6 connector plug, comprising a CAT-x electronic contact  65 . The electronic contact  65  is at least partly surrounded by a sleeve  64  comprising a heat sink layer  67  and an outer cover layer  68 . At the end of the sleeve  64 , a snap fit fastening arrangement  63  is arranged. When a lighting device is connected to the connector plug  61 , a corresponding CAT-x connector port of the lighting device is inserted in the sleeve  64  such that the electronic contact  65  of the connector plug  61  comes in contact with the electronic contact in the connector port of the lighting device (not shown). The outside of the connector port of the lighting device may then come into contact with the inner surface of the heat sink layer  67  of the sleeve  64 , whereby heat may be conducted from the lighting device to the heat sink layer  67  of the connector plug  61 . The heat may then dissipate from the heat sink  67  via the cover  68  to the surroundings. 
         [0044]      FIG. 8  shows the connector plug  61  described with reference to  FIGS. 6 and 7  connected to a lighting device  62 . The cable  66  of the connector plug  61  may be used for suspending the lighting device  62 . Optionally, the connector plug  61  may comprise a reflector  64  arranged to reflect light emitted by the lighting device  62 . 
         [0045]    While embodiments of the invention have been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. For example, the fastening arrangement may be of a bayonet type or any other, preferably rigid, fastening arrangement type. Further, the lighting device may be any kind of lighting device, such as any kind of solid state lighting device or a gas discharge lamp. 
         [0046]    Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.