Patent Publication Number: US-7914178-B2

Title: LED lamp

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to light emitting diode (LED) lamps and, more particularly, to an improved LED lamp having a novel structure for lighting. 
     2. Description of Related Art 
     LED lamp, a solid-state lighting, utilizes LEDs as a source of illumination, providing advantages such as resistance to shock and nearly limitless lifetime under specific conditions. Thus, LED lamps present a cost-effective yet high quality replacement for incandescent and fluorescent lamps. 
     Known implementations of LED modules in an LED lamp make use of a plurality of individual LEDs to generate sufficient light. The large number of LEDs, however, increases price and power consumption of the module. Considerable heat is also generated, which, if not adequately addressed at additional expense, impacts LED lamp reliability. 
     Further, since the LEDs are generally arranged on a printed circuit board having a planar surface, illumination is distributed at a wide variety of spatial angles with marked differences in intensity and brightness, making it unsuitable for environments requiring even and broad illumination. 
     What is needed, therefore, is an LED lamp which can overcome the limitations described. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present apparatus 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 apparatus. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an isometric, assembled view of an LED lamp in accordance with an embodiment of the present disclosure. 
         FIG. 2  is an exploded view of the LED lamp in  FIG. 1 . 
         FIG. 3  is a partly assembled view of a heat dissipation device of the LED lamp in  FIG. 2 . 
         FIG. 4  is an isometric, assembled view of the heat dissipation device of the LED lamp in  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1-2 , an LED lamp, particularly an hang LED lamp, in accordance with an embodiment comprises a heat dissipation device (not labeled) and three LED modules  50  coupled to the heat dissipation device. The heat dissipation device comprises a base  10 , a heat sink  20  attached to a bottom of the base  10 , three heat conducting plates  30  surrounding the heat sink  20  and connecting with the base  10  and the heat sink  20 , and two heat pipes  40  attached to a top surface of each heat conducting plate  30  and connecting with the base  10  and the heat sink  20 . The LED modules  50  are mounted on bottom surfaces of the heat conducting plates  30 , respectively. A first reflector  60  and a second reflector  70  are mounted on each LED module  50  to reflect light generated therefrom. The LED lamp further comprises a cover  80  and three envelopes  85  adhered to the cover  80 . The cover  80  engages the base  10  and covers the heat conducting plates  30 , the heat pipes  40 , the LED modules  50  and the first and second reflectors  60 ,  70  therein. A fixing member  90  is installed on the base  10 , for connecting with a hook attached to a bottom end of a mounting post (not shown) to thereby position the LED lamp at a desired position, for example, a position beneath a ceiling. 
     The base  10  comprises a round chassis  11  and a plurality of fins  12  extending upwardly from a top face of the round chassis  11 . Three holes  14  are defined symmetrically in a center of the chassis  11 . The fins  12  extend radially on the chassis  11  and surrounds the holes  14 . 
     Referring to  FIGS. 3 and 4 , the heat sink  20  comprises a tubular heat conducting body  22  and three symmetrical heat conducting branches  24  extending from an outer surface of the heat conducting body  22 . A longitudinal protrusion  222  is formed on the outer surface of the heat conducting body  22  and located between every two heat conducting branches  24 . Corresponding to the holes  14  of the base  10 , securing holes  224  are defined in top ends of the protrusions  222  for fasteners (not shown) such as screws extending through the holes  14  of the base  10  and screwing therein to securely connect the heat sink  20  and the base  10  together. Understandably, the heat conducting body  22  in the present embodiment, which is a round tube and defines a through hole in a center thereof, could be solid in alternative embodiments, and a cross-section thereof could be a parallelogram, rhombus or any other symmetrical geometrical figures. Each heat conducting branch  24  comprises a first branch  241  extending from the outer surface of the heat conducting body  22  and a plurality of second branches  242  crossing with the first branch  241 . The second branches  242  are apart from each other. An outermost second branch  242  which is far away from the heat conducting body  22  has a shape of a rectangular, flat panel, and other second branches  242  each have an arced shape which is homocentric with the heat conducting body  22 . The first and second branches  241 ,  242  function as fins to increase a heat dissipation area of the heat sink  20 . 
     The heat conducting plates  30  are made of metallic material with good heat conductivity such as aluminum or copper and each comprise a rectangular heat absorbing portion  31  and two engaging portions  32  bending from top and bottom ends thereof. The engaging portion  32  is narrow than the heat absorbing portion  31 . The engaging portion  32  at the bottom end of the heat absorbing portion  31  contacts the outer second branch  242  of the heat conducting branch  24 . The engaging portion  32  at the top end of the heat absorbing portion  31  contacts a bottom surface of the chassis  11 . The top surface of the heat conducting plate  30  which faces the heat sink  20  defines two curved grooves  34 , receiving the heat pipes  40  therein. 
     The heat pipes  40  each comprise a heat absorbing section  41  and two heat dissipating sections  42  bending from two ends of the heat absorbing section  41 . The heat absorbing section  41  corresponds to the heat absorbing portion  31  of the heat conducting plate  30 . The heat dissipating section  42  corresponds to the engaging portion  32  of the heat conducting plate  30 . It is understood that a number of the heat pipes  40  embedded in each heat conducting plate  30  could be varied in alternative embodiments. 
     The LED modules  50  each comprise a printed circuit board  51  and a plurality of LEDs  52  mounted on the board  51  in matrix. The LED modules  50  are mounted under the heat absorbing portions  31  of the heat conducting plates  30  respectively, of which heat generated can be absorbed by the heat conducting plates  30  and further dissipated. 
     The first reflector  60  mounted on the LED module  50  is a flat panel and defines a plurality of apertures  62  corresponding to the LEDs  52 . The second reflector  70  consists of four lateral walls, which surround the LED module  50  and are angled with the LED module  50 . The second reflector  70  defines a small open end adjacent to the LED module  50  and a large open end opposite to the small open end. An inner surface of the second reflector  70  facing the LED module  50  can reflect light generated by the LED module  50 . 
     The cover  80  has a substantially hemispherical shape with an open end thereof engaging the base  10 , thereby covering the heat sink  20  and the LED modules  50 , etc. therein. The cover  80  defines three windows  82  therein corresponding to the three LED modules  50 . The envelopes  85  engage the windows  82  respectively. Light generated by the LED modules  50  can project through the envelopes  85  to illuminate the surrounding environment. 
     The fixing member  90  comprises three chains with top ends thereof combined together. Bottom ends of the chains evenly connect to top of the chassis  11  of the base  10 . The top ends of the chains connect the mounting post to fix the LED lamp at a desired position. Understandably, the fixing member  90  could be a plurality of rods or the like in alternative embodiments. 
     In assembly, the heat sink  20  is secured on a center of the bottom surface of the chassis  11 . The heat pipes  40  are received in the grooves  34  of the heat conducting plates  30 . The engaging portions  32  of the heat conducting plates  30  couple to the chassis  11  and the outer second branches  242  respectively. Specifically, the engaging portion  32  at the top end engages the bottom surface of the chassis  11  at a portion far away from the center thereof (i.e., close to a periphery of the chassis  11 ), and the engaging portion  32  at the bottom end engages the outer second branch  242  close to a free end thereof (i.e., close to a free end of the heat sink  20 ). The heat conducting plate  30  is configured such that angled with the heat conducting body  22  of the heat sink  20  and the chassis  11  of the base  10 . In the present embodiment, the angle defined between the heat conducting plate  30  and the chassis  11  of the base  10  is substantially 60°. Understandably, the sharp angle could be properly varied to adjust an illumination area of the LED lamp. The engaging portions  32  have panel surfaces contacting the chassis  11  and the outer second branch  242 , increasing a contacting surface therebetween. Meanwhile, the dissipating sections  42  of the heat pipes  40  contact the chassis  11  and the outer second branch  242  respectively. 
     The LED modules  50  are mounted under the heat absorbing portions  31  of the heat conducting plates  30  respectively. The first reflectors  60  are mounted under the heat absorbing portions  31  and on the LED modules  50 . The second reflectors  70  surround the LED modules  50 . The cover  80 , with envelopes  85  adhered thereto, engages the chassis  11  of the base  10 , covering the heat sink  20 , the heat conducting plate  30 , the heat pipes  40 , the LED modules  50  and the first and second reflectors  60 ,  70  therein. 
     In operation, light generated by the LED modules  50  adjusted by the first and second reflectors  60 ,  70  project through the envelope  85 . The LED modules  50  are symmetrically coupled on the periphery of the heat sink  20 , increasing the illumination area of the LED lamp. The heat generated by the LED modules  50  can be absorbed by the heat conducting plates  30  and transmitted to the heat sink  20  and the base  10  for further dissipating. The heat pipes  40  can transmit the heat to the heat sink  20  and the base  10  more fast to increase a heat dissipation efficiency of the LED lamp. 
     It is noted that, numbers of the heat conducting branches  24  of the heat sink  20 , the heat conducting plates  24 , the LED modules  50  and the windows  82  of the cover  80  could be varied as desired in alternative embodiments. 
     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 invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.