Patent Publication Number: US-2009237922-A1

Title: LED tube light

Description:
BACKGROUND OF THE INVENTION  
     The invention relates to lighting. The invention more particularly, although not exclusively, relates to tube lighting with encased LEDs. 
     Fluorescent tubes have been used for many years as an energy-efficient alternative to incandescent lighting. Modern high-intensity LEDs are even more efficient than fluorescent tubes, however existing fluorescent light fittings are designed to receive fluorescent tubes of various standard form factors. Some manufacturers provide an LED replacement light in a standard fluorescent tube form factor for easy retrofitting. Such replacement tubes are known to comprise an elongate planar circuit board extending longitudinally within a plastics tube and comprising an array of LEDs which are soldered onto the circuit board—all facing in the same direction transverse to the longitudinal extent of the tube. 
     The above known configuration does not result in a desirable widespread dispersion of light as the known light fittings were originally designed for fluorescent tubes which radiate light in all radial directions transverse to the longitudinal extent of the fluorescent tubes. 
     Another problem associated with known fluorescent tubes is of course associated with breakage and disposal because the tubes contain a phosphor coating and Mercury. 
     OBJECTS OF THE INVENTION  
     It is an object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages and/or more generally to provide an improved LED Tube light. 
     DISCLOSURE OF THE INVENTION  
     There is disclosed herein a tubular light, comprising:
         a light-transmissive tube;   an end cap fitted to an end of the tube;   an electrical contact terminal extending from the end cap; and   an LED attached to the end cap and receiving electrical power via the contact terminal and configured to emit light along the tube to impinge upon the tube internally.       

     Preferably, the tube is cylindrical and has a said end cap fitted to each end thereof in such manner that the LED of each end cap is directed toward the other end cap. 
     Preferably, each end cap has a pair of said electrical contact terminals. 
     Preferably, each end cap comprises an array of LEDs, in which each LED of the array is configured to emit light along the tube to impinge upon the tube internally. 
     Preferably, the light-transmissive tube is substantially clear. 
     Alternatively, the light-transmissive tube is translucent. Alternatively, the light-transmissive tube is substantially clear with a translucent coating on its inner and/or outer surfaces. 
     Preferably, the tubular light is sized and shaped to be received by and functional with a light fitting designed for a fluorescent tube of standard form factor. 
     There is further disclosed herein a tubular light, comprising:
         a light-transmissive tube;   an end cap at an end of the tube;   an electrical contact terminal on the end cap;   an elongate member located within the tube;   a multitude of LEDs mounted upon the elongate member to receive electrical power via the electrical contact and wherein the LEDs are configured to emit light at a number of angularly offset substantially radial directions toward an inner surface of the tube.       

     Preferably, the elongate member is substantially cylindrical having a central longitudinal axis. 
     Preferably, the LEDs are provided in a number of linear arrays which extend longitudinally of the elongate member and wherein each said array is offset radially with respect to each other array, and wherein each LED is directed radially outwardly of the longitudinal axis. 
     Preferably, each end cap includes an electrical contact pin associated with the respective electrical contact terminal and the contact pin engages the elongate member to convey electrical power to the LEDs. 
     Preferably, each end cap has a pair of said electrical contact terminals and a pair of said electrical contact pins. 
     Preferably, the light-transmissive tube is substantially clear. 
     Alternatively, the light-transmissive tube is translucent. 
     As a further alternative, the light-transmissive tube can be substantially clear with a translucent coating on its inner and/or outer surfaces. 
     Preferably, the light is sized and shaped to be received by and functional with a light fitting designed for a fluorescent tube of standard form factor. 
     There is further disclosed herein a light fitting, comprising:
         a light-transmissive tube curved in a C-shape;   an end cap at an end of the tube;   an electrical contact terminal on the end cap;   a C-shaped internal member located within the tube;   a multitude of LEDs mounted upon the internal member to receive electrical power via the electrical contact and wherein the LEDs are configured to emit light at a number of angularly offset substantially radial directions toward an inner surface of the tube.       

     Preferably, the internal member has a curved central axis. 
     Preferably, the LEDs are provided in a number of linear arrays which extend along the internal member and wherein each said array is offset radially with respect to each other array, and wherein each LED is directed radially outwardly of the central axis. 
     Preferably, each end cap includes an electrical contact pin associated with the respective electrical contact terminal and the contact pin engages the internal member to convey electrical power to the LEDs. 
     Preferably, each end cap has a pair of said electrical contact terminals and a pair of said electrical contact pins. 
     Preferably, the light-transmissive tube is substantially clear. 
     Alternatively, the light-transmissive tube can be translucent. 
     Alternatively, the light-transmissive tube can be substantially clear with a translucent coating on its inner and/or outer surfaces. 
     The light fitting can be sized and shaped to be received by and functional with a light fitting designed for a fluorescent tube of standard form factor. 
     Preferably, the tube comprises mutually interconnected upper and lower C-shaped shells. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
       Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: 
         FIG. 1  is a schematic perspective illustration of an LED tube light; 
         FIG. 2  is a schematic side-on illustration of the LED tube light of  FIG. 1 ; 
         FIG. 3  is a schematic parts-exploded side-on illustration of the LED tube light of  FIGS. 1 and 2 ; 
         FIG. 4  is a schematic perspective illustration of another LED tube light; 
         FIG. 5  is a schematic side-on illustration of the LED tube light of  FIG. 4 ; 
         FIG. 6  is a schematic end elevation of inner parts of the LED tube light of  FIGS. 4 and 5 ; and 
         FIG. 7  is a schematic parts-exploded side-on illustration of the LED tube light of  FIGS. 4 and 5 . 
         FIG. 8  is a schematic plan illustration of yet another LED light fitting; 
         FIG. 9  is a schematic end elevation of inner parts of the LED light fitting of  FIG. 8 ; 
         FIG. 10  is a schematic plan illustration of the inner parts of the LED light fitting of  FIG. 9 ; 
         FIG. 11  is a schematic parts-exploded perspective illustration of the LED light fitting of  FIGS. 8 to 10 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     In  FIGS. 1 to 3  of the accompanying drawings there is depicted schematically a tube light  10  made in a standard fluorescent tube form factor for fitting into standard light fittings. The tube light  10  comprises a light-transmissive tube  11  with end caps  12  each having electrical contact terminals  13  projecting longitudinally therefrom for contact with corresponding terminals in the light fitting itself. 
     The tube  11  is typically of plastics material or glass and might be substantially clear or translucent. It might be of substantially clear material with a translucent coating on its inner and/or outer surfaces. 
     LEDs  14  are mounted to each of the end caps  12  and face in the longitudinal direction of the tube light  10 . The LEDs  14  are typically high-intensity devices capable of emitting very bright and narrowly diverging light which impinges upon the inner surface of the plastics tube  11  causing the tube  11  to glow and thereby radiate light in all radial directions. 
     As the tube light  10  is intended to be installed in standard high-voltage light fittings, a voltage transformer or transformers can be housed within one or both end caps  12  to supply the appropriate low voltage source to the LEDs  14 . 
     In  FIGS. 4 to 7  there is depicted schematically a tube light  100  made in a standard fluorescent tube form factor for fitting into standard light fittings. The tube light  100  comprises a light-transmissive tube  11  with end caps  12  each having external electrical contact terminals  13  projecting longitudinally therefrom for contact with corresponding terminals in the light fitting itself. There are two corresponding internal contact pins  15  at each end cap  12  which project internally of the tube  11 . 
     The tube  11  is typically of plastics material or glass and might be substantially clear or translucent. It might be of substantially clear material with a translucent coating on its inner and/or outer surfaces. 
     Located within the tube  11  is an elongate member  16  having a pair of electrical sockets  17  (see  FIG. 11  for detail) at each end and into which the internal contact pins  15  of each end cap are received. 
     The elongate member  16  has a multitude of LEDs  14  extending therealong and spaced radially thereabout. In the depicted embodiment, there are four elongate parallel rows of LEDs  14  with each row being spaced evenly about the elongate member  16  as shown in  FIG. 6 . 
     Alternatively, there could be two, three, or five or more rows of LEDs. As a further alternative, a single row or multiple rows of LEDs could be spiralled or zigzagged about the elongate member  16 . The LEDs are electrically connected internally of the elongate member with the electrical sockets (not shown) at each end thereof. 
     As the tube light  100  is intended to be installed in standard high-voltage light fittings, a voltage transformer or transformers can be housed within one or both end caps  12  to supply the appropriate low voltage source to the LEDs  14  via the pins  15  which are of course inserted into the sockets at each end of the elongate member  16 . 
     When the LEDs  14  are illuminated, they emit light upon the inside surface of the tube  11 . If by choice the tube  11  is substantially clear, the light from each LED passes through the tube  11  substantially unaffected. Where sufficient LEDs are provided, the resultant overall emission of light from the tube light is in substantially all radial directions. If on the other hand the tube  11  is translucent or substantially clear with a translucent inner and/or outer coating, the tube will defuse and thereby soften the light somewhat, but otherwise result in light emission in substantially all radial directions. 
     In  FIGS. 8 to 11  there is depicted schematically a light fitting  300  made in a standard C-shaped or “doughnut” fluorescent tube form factor for fitting into standard light fittings. The light fitting  300  comprises a light-transmissive C-shaped tube  11   a / 11   b  with end caps  12  each having external electrical contact terminals  13  projecting therefrom for contact with corresponding terminals in the light fitting itself. There are two corresponding internal contact pins  15  at each end cap  12  which project internally of the tube. 
     The tube  11   a / 11   b  comprises an upper tube shell  11   a  and a lower tube shell  11   b  which are mutually interconnected to form a C-shaped enclosure having a substantially circular cross-section. Each shell is typically of plastics material or glass and might be substantially clear or translucent. It might be of substantially clear material with a translucent coating on its inner and/or outer surfaces. 
     Located within the tube  11   a,    11   b  is an internal member  16  having a pair of electrical sockets  17  at each end and into which the internal contact pins  15  of each end cap are received. 
     Apart from the C-shaped nature of the internal member  16 , its function and provision of LEDs is for all intents and purposes the same as elongate member  16  which is described above in relation to the embodiment depicted in  FIGS. 4 to 7 . When the LEDs  14  are illuminated, they emit light upon the inside surface of the tube shells  11   a / 11   b.  If by choice the tube shells are substantially clear, the light from each LED passes through the shells  11   a,    11   b  substantially unaffected. Where sufficient LEDs are provided, the resultant overall emission of light from the light fitting is in substantially all radial directions. If on the other hand the tube shells  11   a,    11   b  are translucent or substantially clear with a translucent inner and/or outer coating, the tube will defuse and thereby soften the light somewhat, but otherwise result in light emission in substantially all radial directions. As there are two separate shells, it is of course not essential that they both be provided with the same diffusive features. For example, shell  11   a  might be clear, translucent or even opaque, whereas shell  11   b  might be clear, translucent or otherwise as described above. 
     It should be appreciated that modifications and alterations obvious to those skilled in the art are not to be considered as beyond the scope of the present invention. For example, the inside surface of the tube  11  could be roughened or be otherwise provided with surface imperfections or projections to better receive the light emitted by the LEDs  14 . Furthermore, instead of providing a single elongate member  16 , a pair of half length elongate members could be provided with each member being attached to only one of the end caps  12 .