Patent Abstract:
An LED tube includes a light guide, an LED and a reflector. The light guide includes a light incident face at an end thereof and a light emerging face adjacent to the light incident face. The reflector is mounted on an opposite end of the light guide. The reflector forms a light reflective face facing the light guide to reflect light backward into the light guide.

Full Description:
BACKGROUND 
     1. Technical Field 
     The disclosure generally relates to an LED (light emitting diode) tube, and more particularly, to an LED tube with a light reflective face. 
     2. Description of Related Art 
     Nowadays LEDs (light emitting diodes) are applied widely in various occasions for illumination. A typical LED tube includes a light guiding rod and an LED placed on an end of the rod. The rod generally forms micro structures for destroying total reflection of the light within the rod. Thus, light emitted from the LED and into the rod can be diffused by the micro structures to radiate out of the rod. 
     The LED is a highly pointed light source. The light passing through the end of the rod has a large ratio directly reaching the opposite end of the rod. However, the typical LED tube does not have any optical structure formed on the opposite end of the rod to collect the light. Thus, the light reaching the opposite end of the rod cannot be effectively utilized, thereby causing waste of the light. As a result, the light emitting efficiency of the LED tube is limited. 
     What is needed, therefore, is an LED tube with a reflective face which can address the limitations described. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the various views. 
         FIG. 1  shows an LED tube in accordance with a first embodiment of the present disclosure. 
         FIG. 2  shows an LED tube in accordance with a second embodiment of the present disclosure. 
         FIG. 3  shows an LED tube in accordance with a third embodiment of the present disclosure. 
         FIG. 4  shows an LED tube in accordance with a fourth embodiment of the present disclosure. 
         FIG. 5  shows the LED tube of  FIG. 4  mounted on a lamp supporter 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an LED (light emitting diode) tube  10  in accordance with a first embodiment of the present disclosure is shown. The LED tube  10  includes a light guide  20 , an LED  30  placed on a left end of the light guide  20  and a reflector  40  attached on a right end of the light guide  20 . 
     The light guide  20  may be made of transparent material such as epoxy, glass or the like. In this embodiment, the light guide  20  is elongated and straight. The light guide  20  includes a light incident face  26  at the left end thereof, an end face  28  at the right end thereof and a light emerging face  22  at a bottom face thereof. The light incident face  26  is a flat face. The end face  28  is a curved convex face. The light emerging face  22  is located between the light incident face  26  and the light reflective face  28 . A light diffusion face  24  is formed on a top face of the light guide  20 . The light diffusion face  24  may include a plurality of micro structures  50  such as protrusions or grooves which can diffuse light towards various directions. 
     The LED  30  is located at the light incident face  26  of the light guide  20 . The LED  30  may be a white LED  30  which can emit white light when being powered. The LED  30  directly contacts the light incident face  26  of the light guide  20  so that the white light emitted from the LED  20  can transmit to an interior of the light guide  20  through the light incident face  26 . 
     The reflector  40  is attached on the end face  28  of the light guide  20 . The reflector  40  may be formed by plating a metal film on the end face  28  of the light guide  20  or adhering a metal layer on the end face  28  of the light guide  20 . The reflector  40  includes a curved concave inner face and a curved convex outer face  44 . The inner face of the reflector  40  acts as a reflective face  42  directly contacting the end face  28  of the light guide  20 . The light transmitting to the end face  28  from the light incident face  26 , can be reflected by the reflective face  42  back to the interior of the light guide  20  through the end face  28 . The reflected light is then diffused by the light diffusion face  24  to radiate out of the light guide  20  through the light emerging face  22 . Therefore, the light transmitting to the end face  28  of the light guide  20  is not wasted, and a light emitting efficiency of the LED tube  10  is raised accordingly. 
     Alternatively, as shown in  FIG. 2 , the end face  28   a  of the light guide  20  can also be a flat face. The reflective face  42   a  of the reflector  40   a  is thus spaced from the end face  28   a  of the light guide  20  via a gap  200 . In this embodiment, the reflective face  42   a  has a curvature larger than that of the reflective face  42  of  FIG. 1 . The outer face  44   a  of the reflector  40   a  is flat. A distance between the outer face  44   a  and the reflective face  42   a  of the reflector  40   a  gradually decrease and then increase from a top to a bottom of the reflector  40   a . Light emerging from the end face  28   a  of the light guide  20  passes through the gap  200 , and is then reflected by the reflective face  42   a  of the reflector  40   a  back to the interior of the light guide  20  through the gap  200 . The backward light is then diffused by the light diffusion face  24  to radiate out of the light guide  20  through the light emerging face  22 . 
     Furthermore, as shown in  FIG. 3 , the reflector  40   a  of  FIG. 2  can be used with the light guide  20  of  FIG. 1 . The reflective face  42   a  of the reflector  40   a  is still spaced from the end face  28  via the gap  200  since the reflective face  42   a  has a curvature larger than that of the end face  28 . 
     Referring to  FIG. 4 , the LED tube  10  can further includes two lids  70  mounted on the left end and the right end of light guide  20 . Each lid  70  includes a housing  72  and a two pins  74  protruding outwardly from an outer face of the housing  72 . The housing  72  defines a gap  720  in an inner face thereof and a sidewall  78  surrounding the gap  720 . The left end and the right end of the light guide  20  are inserted to the two cavities  720  of the two housings  72 , respectively. The left end and the right end of the light guide  20  are engaged with and surrounded by the sidewalls  78  of the two housings  72 , respectively. Thus, the two lids  70  are fixed on the light guide  20 . The LED  30  is received in the gap  720  of a left lid  70 , and electrically connected to the two pins  74  of the left lid  70  via two wires  76 . The right lid  70  does not have LED  30  and wire  76  therein. In other words, the two pins  74  of the right lid  70  do not electrically connect with the LED  30 . In this embodiment, the reflector  40   a  of  FIG. 3  is incorporated within the right lid  70 , and the gap  200  of the reflector  40   a  is the gap  720  of the right lid  70 . That is to say, an inner face of the housing  72  of the right lid  70  defining the gap  720  forms the reflective face  42   a  of  FIG. 3 . Alternatively, the housing  72  of the left lid  70  may also incorporate the reflector  40   a  of  FIG. 3  therein for increasing light utilizing efficiency of the LED  30 . 
     Referring to  FIG. 5 , the LED tube  10  of  FIG. 4  can be mounted to a lamp support  60 . The lamp support  60  has a shape similar to a typical tube support. The lamp support  60  includes two sockets  62  and a lampshade  64  mounted on the two sockets  62 . The two pins  74  of each lid  70  are inserted to a corresponding socket  62  for fixing the LED tube  10  to the lamp support  60 . However, only the left socket  62  supplies power for the LED  30  through the pins  74  of the left lid  70 , the right socket  62  does not supply power for the LED  30  since no wire is connected to the pins  74  of the right lid  70 . The lampshade  64  covers the light guide  20  to prevent dust or other contaminant from falling on the light guide  64 . 
     It is to be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

Technology Classification (CPC): 5