Abstract:
An LED lamp assembly includes a fixing holder adapted for positioning the LED lamp assembly at a desired position and a plurality of LED lamp modules superposed one by one on the fixing holder and spaced from each other. The LED lamp modules gradually increase in dimension along a superposing direction of the LED lamp modules. Each of the LED lamp modules includes a heat sink and an LED module attached to the heat sink. The heat sinks of the LED lamp modules gradually increase in dimension along the superposing direction of the LED lamp modules. The LED lamp modules are connected by a rod between the heat sinks of adjacent ones of the LED lamp modules.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The disclosure relates to LED (light emitting diode) lamp assemblies for illumination purpose and, more particularly, relates to an improved LED lamp assembly having a good heat dissipation capability and large illumination area. 
         [0003]    2. Description of Related Art 
         [0004]    An LED lamp is a type of solid-state lighting that utilizes LEDs as a source of illumination. An LED is a device for transferring electricity to light by using a theory that, if a current is made to flow in a forward direction through a junction region comprising two different semiconductors, electrons and holes are coupled at the junction region to generate a light beam. The LED has an advantage that it is resistant to shock, and has an almost eternal lifetime under a specific condition; thus, the LED lamp is intended to be a cost-effective yet high quality replacement for incandescent and fluorescent lamps. 
         [0005]    Since LED lamps have many advantages; the LED lamps often act as street, lawn or home lamps for illumination purpose. Known implementations of LED modules in an LED lamp make use of a plurality of individual LEDs to generate light that is ample and of satisfactory spatial distribution. 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. 
         [0006]    Further, since the LEDs are generally arranged on a printed circuit board having a flattened surface, illumination is distributed at a wide variety of spatial angles with sharp differences in intensity and brightness, making it unsuitable for environments requiring even and broad illumination. Finally, the LEDs mounted on the flattened surface of the printed circuit board cannot have a large area of illumination. 
         [0007]    What is needed, therefore, is an improved LED lamp assembly which can overcome the above problems. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    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 several views. 
           [0009]      FIG. 1  is an isometric, assembled view of an LED lamp assembly in accordance with an embodiment of the disclosure. 
           [0010]      FIG. 2  is an exploded view of the LED lamp assembly of  FIG. 1 . 
           [0011]      FIG. 3  is an inverted, exploded view of the LED lamp assembly of  FIG. 1 . 
           [0012]      FIG. 4  is a cross-sectional view of the LED lamp assembly of  FIG. 1 , taken along a line IV-IV thereof. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Referring to  FIGS. 1-2 , an LED lamp assembly in accordance with an embodiment of the disclosure is illustrated. The LED lamp assembly comprises a fixing holder  40  adapted for positioning the LED lamp assembly at a desired position, a third LED lamp module  30  securely disposed on the fixing holder  40 , a second LED lamp module  20  superposing on the third lamp module  30  and a first LED lamp module  10  superposing on the second LED lamp module  20 . The LED lamp assembly further comprises fixing rods  50  supporting the first, second and third LED lamp modules  10 ,  20 ,  30 . 
         [0014]    Also referring to  FIG. 3 , the first, second and third LED lamp modules  10 ,  20 ,  30  all have a similar configuration; only sizes of the first, second and third LED lamp modules  10 ,  20 ,  30  are different, in which the first LED lamp module  10  is larger than the second LED lamp module  20 , which in turn is larger than the third LED lamp module  30 . Taking the first LED lamp module  10  as an example, each of the first, second and third LED lamp modules  10 ,  20 ,  30  comprises a heat sink  12 , an LED module  14  attached on a bottom face of the heat sink  12  and an envelope  16  fixed to the bottom face of the heat sink  12  and covering the LED module  14 . 
         [0015]    The heat sink  12  is a circular and made of a metal with a good heat conductivity such as copper or aluminum. The heat sink  12  comprises a periphery portion  121 , a central portion  123  and four bridges  125  equidistantly and radially extending at a periphery of the central portion  123 . An outer portion of each bridge  125  interconnects the central portion  123  and the periphery portion  121 , and an inner portion of each bridge  125  define a threaded hole  1250  therein. The periphery portion  121  has a top face extending a plurality of fins  122  upwardly and perpendicularly, and a bottom face defining an annular concaved receiving portion  120  therein. In this embodiment, the receiving portion  120  is an annular trough between a periphery edge of the periphery portion  121  and the central portion  123 . The four bridges  125  evenly distributed between the periphery portion  121  and the central portion  123 . The bridges  125  have first ends thereof extending into the receiving portion  120  and second ends thereof extending to the central portion  123 . A circular recession is defined at a center of a top face of the central portion  123  for receiving a driving circuit module therein. The fins  122  radially surround the recession. A round back plate  18  is disposed on the top face of the heat sink  12  and correspondingly covers the recession. A hollow column-shaped first fixing portion  100  extends downwardly and perpendicularly from a center of a bottom face of the central portion  123 . 
         [0016]    The LED module  14  comprises an annular printed circuit board  140  and a plurality of LEDs  142  arranged evenly thereon. The printed circuit board  140  defines four cutouts  141  in an inner edge thereof, which are equidistantly spaced from each other. The LED module  14  is directly received in the receiving portion  120  of the heat sink  12  with the cutouts  141  thereof fitly receiving the first ends of the bridges  125  of the heat sink  12 . 
         [0017]    The envelope  16  is annular and correspondingly disposed on the receiving portion  120  of the heat sink  12 , with four ears evenly extending from an outer edge thereof and overlapping four ears evenly extending from an outer edge of the periphery portion  121  of the heat sink  12 , thereby cooperating with the receiving portion  120  to enclose the LED module  14  between the envelope  16  and the heat sink  12 . Screws (not shown) are used to extend through four holes (not labeled) defined in the envelope  16  near an inner hole (not labeled) thereof and screw into the threaded holes  1250 . Furthermore, screws (not shown) are used to extend through the ears  160  and screw into threaded holes  1210  defined in protrusions  1212  of the periphery portion  121 . Thus, the envelope  16  is secured to the heat sink  12 . 
         [0018]    Also referring to  FIG. 4 , the back plates  18  of the second and third LED lamp modules  20 ,  30  each further comprise a hollow, column-shaped second fixing portion  200  extending upwardly and perpendicularly from a center of a top face thereof. Diameters of the heat sinks  12  of the first, second and third LED lamp modules  10 ,  20 ,  30  gradually decrease from top to bottom. A diameter of the LED module  14  of the first LED lamp module  10  is larger than that of the heat sink  12  of the second LED lamp module  20 , and a diameter of the LED module  14  of the second LED lamp module  20  is larger than that of the heat sink  12  of the third LED lamp module  30 . 
         [0019]    The fixing holder  40  is a hollow tube with an opening (not labeled) defined at a bottom thereof. The opening is used to engagingly receive a top end of a supporting rod (not shown) in order to secure the LED lamp assembly at a required position. A hollow column-shaped third fixing portion  300  extends upwardly and perpendicularly from a center of a top face of the fixing holder  40 . 
         [0020]    The fixing rods  50  each are an elongated column. A first of the fixing rods  50  stands vertically between and connects the first and second LED lamp modules  10 ,  20 , wherein a top end of the first fixing rod  50  is engagingly received in the first fixing portion  100  of the first LED lamp module  10  and a bottom end of the first fixing rod  50  is engagingly received in the second fixing portion  200  of the second LED lamp module  20 . A second of the fixing rods  50  stands vertically between and connects the second and third LED lamp modules  20 ,  30 , wherein a top end of the second fixing rod  50  is engagingly received in the first fixing portion  100  of the second LED lamp module  20  and a bottom end of the second fixing rod  50  is engagingly received in the second fixing portion  200  of the third LED lamp module  30 . A third of the fixing rods  50  stands vertically between and connects the third LED lamp module  30  and the fixing holder  40 , wherein a top end of the third fixing rod  50  is engagingly received in the first fixing portion  100  of the third LED lamp module  30  and a bottom end of the third fixing rod  50  is engagingly received in the third fixing portion  300  of the fixing holder  40 . 
         [0021]    Referring to  FIGS. 1-4  again, in assembly, the first, second and third LED lamp modules  10 ,  20 ,  30  are parallel to and spaced from each other. The fixing rods  50  are aligned with each other, whereby the first, second and third LED lamp modules  10 ,  20 ,  30  are coaxial and superposed. Diameters of the heat sinks  12  of the first, second and third LED lamp modules  10 ,  20 ,  30  gradually decrease from top to bottom, which makes the LED lamp assembly integrally having an inverted cone configuration. 
         [0022]    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.