Abstract:
A fluorescent light source includes at least one tube surrounding an interior region. The tube has a plurality of tubular portions, each one of which is disposed adjacent to at least one other tubular portion. The fluorescent light source has a support member, and each one of the tubular portions is configured to extend vertically from the support member and to curve outwardly away from the interior region.

Description:
PRIORITY CLAIM 
   This application is a continuation of and claims priority to and the benefit of U.S. patent application Ser. No. 10/799,466, filed on Mar. 12, 2004 now U.S. Pat. No. 7,012,373 and entitled “Electronic Energy-Saving Fluorescent Lamp of Ultra-Short Chayote-Shaped Compact Type,” which, in turn, claims priority to Chinese Patent Application No. CN03222136.3, filed May 26, 2003, entitled “Ultra-Short Chayote-Like Compact Electronic Energy-Saving Fluorescent Lamp.” 

   BACKGROUND OF THE INVENTION 
   This utility model relates to illuminating lamps, in particular to an ultra-short Chayote-like compact electronic energy-saving fluorescent lamp. 
   The existing compact electronic energy-saving fluorescent lamps (hereinafter referred to as CFL) with medium and low power smaller than 24 W have basically a column structure in their structural configuration, e.g., U-shape, N-shape, H-shape, the shape of double screw bolt, etc. These existing CFL&#39;s have a cylindrical source of light in common, meanwhile the lower cover used to secure the luminous tube in these lamps is of planar construction. The electronic ballast is usually assembled by separate type components. These separate type components (including a current limiting inductor with larger size occupying relatively larger space) are totally mounted on the component side of the Printed Circuit Board (PCB), making the upper and lower covers for receiving the electronic ballast have larger size. Therefore, such a CFL has many disadvantages. One of the disadvantages is the light utilization rate is much lower because the light sent out from the inside surface of the luminous tube is kept out by the near and the opposite luminous tubes. Another disadvantage is the heat generated by the luminous tubes is difficult to be emitted because the luminous tubes of the fluorescent lamp are abutted against one another. Thus, a considerable amount of heat is accumulated, resulting in too high temperature in the working area of the luminous tube and the luminous efficiency is reduced. An additional disadvantage is the luminous tube is longer. 
   SUMMARY OF THE INVENTION 
   Based on the full analysis of the CFL&#39;s with power smaller than 24 W, the present invention eliminates or decreases their deficiencies, provides solutions for solving these problems and implements the corresponding technical measures which, in one embodiment, results in a Chayote-like compact electronic energy-saving fluorescent lamp (hereinafter referred to as Chayote-like lamp). 
   In one embodiment, the Chayote-like lamp comprises a base, an upper cover, a lower cover, a luminous tube combination or luminous tube and an electronic ballast. The luminous tube is formed by bridge connection of several luminous tubes. The current limiting inductor of the electronic ballast is welded and assembled on the face of the weld of the Printed Circuit Board (PCB). A cylindrical cavity protrudes downward from the bottom center of the lower cover, characterized in that said Chayote-like lamp is formed by assembling several Chayote-like lamp units—finger-shaped luminous tubes bent so as to have a certain curvature and uniformly distributed about the lamp axis. The current limiting inductor welded and assembled on the face of the weld of the Printed Circuit Board (PCB) is placed in a cylindrical cavity protruding downward from the bottom center of the lower cover. 
   There are several beneficial effects of the present invention. One beneficial effect is that pulling apart the gap (identified in the figures as gap  19 ) between each unit luminous tube (about six times or more than that of the column structure) causes the light sent out from the inside of the luminous tube to be directly sent out through the adjacent gaps and the opposite gaps. Thereby, the light utilization rate is greatly improved. Another beneficial effect is that, for each unit U-shaped luminous tube of the Chayote-like lamp, the U-shaped luminous tube is bent at a certain curvature into a finger shape. Thereby, the length of the luminous tube is shortened. The length of the luminous tube of the Chayote-like lamp is much shorter compared to the columnar luminous tube with the same power. 
   Yet another beneficial effect of the present invention is that the cylindrical cavity protrudes downward from the bottom of the lower cover in the Chayote-like lamp for receiving the current limiting inductor. This configuration shortens the length of the upper cover on the basis of decreasing the length of the electronic ballast. 
   Still another beneficial effect is that the gap between the unit luminous tubes of the Chayote-like lamp becomes larger, which results in sufficient heat emission and lowers the temperature in the working area of the luminous tube. Thus the luminous efficiency of the Chayote-like lamp is greatly improved. Meanwhile, the temperature rise of the electronic ballast can be reduced and thus, the reliability of the Chayote-like lamp is improved, and its service life is prolonged. 
   The aforementioned and the other objects, features and advantages of the present invention, to those skilled in the art, will be better understood with regard to the following Detailed Description and accompanying figures. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
       FIG. 1A  is a front elevation view of one of the finger-shaped unit luminous tubes of the luminous tube combination or luminous tube in one embodiment of the present invention. 
       FIG. 1B  is a side elevation view of the finger-shaped luminous tube of  FIG. 1A . 
       FIG. 1C  is a top or plan view of the finger-shaped luminous tube of  FIG. 1A . 
       FIG. 2A  is a top or plan view of the luminous tube combination or luminous tube in one embodiment of the present invention. 
       FIG. 2B  is a side elevation view of the luminous tube combination or luminous tube of  FIG. 2A . 
       FIG. 3A  is a side elevation view of the upper cover of the lamp in one embodiment of the present invention. 
       FIG. 3B  is a bottom view of the upper cover of  FIG. 3A . 
       FIG. 4A  is a side elevation view of the lower cover of the lamp in one embodiment of the present invention. 
       FIG. 4B  is a bottom view of the lower cover of  FIG. 4A . 
       FIG. 5A  is a diagrammatic side elevation view of the electronic ballast of the lamp in one embodiment of the present invention. 
       FIG. 5B  is a bottom view of the electronic ballast of  FIG. 5A . 
       FIG. 6A  is a side elevation view of the lamp in one embodiment of the present invention. 
       FIG. 6B  is a side elevation view of the lamp diagrammatically illustrating the inner components of the lamp in one embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to  FIGS. 1A-2B , in one embodiment, the luminous tube combination or luminous tube  4  of the lamp  18  (illustrated in  FIGS. 6A-6B ) is the combination of several unit luminous tubes  7 . Each unit luminous tube  7  is formed by bending a U-shaped tube at certain curvature into a finger-shaped unit luminous tube  7  and building up the finger-shaped unit luminous tubes  7  according to the shape of Chayote. According to the different requirements to the designed unit luminous tubes  7 , two to five finger-shaped unit luminous tubes  7  with the same curvature are connected in a manner of bridge connection to form a fluorescent lamp with the shape of a Chayote. The tube diameter of the finger-shaped unit luminous tube  7  is in the range of eight to eleven millimeters. The finger-shaped unit luminous tubes  7  are connected to one another in the sequence of connection bridge  8 . The filaments  9  (illustrated in  FIG. 6B ) are cased in both the beginning and the end finger-shaped unit luminous tubes  7 , meanwhile rare earth tricolor phosphor powder is uniformly coated on the inner walls of all the finger-shaped unit luminous tubes  7 . Also, a certain amount of mercury and inert gas is filled in the luminous tube combination or luminous tube  4  of the Chayote-like lamp  18 . 
   As illustrated in  FIGS. 3A-3B , the lamp  18  has an upper cover  2  in one embodiment of the present invention. The upper cover  2  is of a horn shape. There is external thread structure  2   a  on its upper half section and there is annular key and groove structure  2   b  inside of the lower section. The external thread  2   a  is used for connecting and securing the base  1 . The key and groove structure  2   b  is used for the mechanical connection of upper cover  2  to lower cover  3 . The inner cavity  2   c  of the upper cover  2  is used for receiving electronic ballast  5 . 
   As illustrated in  FIGS. 4A-4B , the lamp  18  also has a lower cover  3  in one embodiment of the present invention. The lower cover  3  is of a funnel shape. A cylindrical cavity  3   a  is protruded downward from its bottom center. Eight (or four or six or ten) circular through holes  3   b  are distributed around the cavity  3   a . A circular peripheral border  3   c  with certain thickness of the lower cover  3  is provided on the outmost edge. Annular key and groove  3   d  are located on the upper part of the peripheral border  3   c . The protruded cylindrical cavity  3   a  is used for placement of current limiting inductor  6 . The circular through holes  3   b  are used for mounting and securing the luminous tube of the Chayote-like lamp  18 . The portion  3   e  between the peripheral border  3   c  and the cavity  3   a  is used for filling the securing glue. The annular key and groove  3   d  is used for the mechanical connection to the upper cover  2 . 
   In one embodiment, the lamp  18  also includes an electronic ballast  5 , as illustrated. The electronic ballast  5  comprises a Printed Circuit Board (PCB)  11 , current limiting inductor  6  and several resistors, capacitors, diodes, triodes, etc. (not shown). As illustrated in  FIG. 6B , a plane  21  extends through the PCB  11  and the cover  3 . The upper surface  11   a  of the PCB  11  is the face of component and its lower surface  11   b  is the face of weld. The electronic ballast  5  defines a space  5   a  for positioning the resistors, capacitors, diodes, triodes, etc. These components are welded and assembled on the face  11   a  of component  11 . The current limiting inductor  6  is welded and assembled on the face  11   b  of the weld. In the embodiment illustrated in  FIG. 6B . the inductor  6  extends less than twenty-five percent (and therefore less than fifty percent) of the distance (D) from the plane  21  to the end  23  of the luminous tubes  7 . In addition, two input junction points  13  and four output junction points  14  are also disposed on PCB  11 . The input junction points  13  are electrically connected to power supply connecting wire  12  so as to provide the AC power supply to the electronic ballast  5 . The four output junction points  14  are electrically connected to the filament outlet  10  of the luminous tube combination or luminous tube  4  of the Chayote-like lamp  18  so as to provide high frequency voltage and current to the luminous tube combination or luminous tube  4  of the Chayote-like lamp  18  and two sets of filaments  9 . 
   As illustrated in  FIGS. 6A and 6B , in one embodiment the Chayote-like lamp  18  includes a base  1 , an upper cover  2 , a lower cover  3 , a luminous tube combination  4  of the Chayote-like lamp  18  and an electronic ballast  5 . Their connection is divided into electrical connection and mechanical connection. The electrical connection includes the electrical connection of one end of the two power supply connecting wires  12  of the base  1  to the center point of the base  1  and the thread portion  17 , respectively. The thread portion  17  extends along an axis  25 . The electrical connection also includes the other end of the wires  12  being connected to the two input junction points  13 , respectively. In this electrical connection, the four output junction points  14  on PCB  11  are connected to the terminals of the four filament outlets  10  of the Chayote-like lamp  18 . 
   The mechanical connection of the lamp  18  includes: (a) the connection of base  1  to upper cover  2 ; (b) the connection of lower cover  3  to the luminous tube combination or luminous tube  4  of the Chayote-like lamp  18 ; and (c) the connection of upper cover  2  to lower cover  3  after the electrical connection. In the case of (a), the base  1  and upper cover  2  are connected by thread and clasped after they are screwed down. In the case of (b), the upper one end of the luminous tube combination  4  of the Chayote-like lamp  18  is inserted into the circular through holes  3   b  of the lower cover  3  and their joint is fixed using securing glue. In the case of (c), this connection is located in the cylindrical cavity formed after the current limiting inductor  6  is placed into the lower cover  3 . The electronic ballast  5  falls into the lower cover  3  and, at the same time, the upper cover  2  is used to cover the electronic ballast  5 . The upper cover  2  and the lower cover  3  are tightly connected to one another through annular key groove. 
   Because the luminous tube combination  4  of the present invention has a shape of a Chayote, a cylindrical cavity is protruded from the center of the bottom of the lower cover  3  towards the direction of the luminous tube combination or luminous tube  4 . The current limiting inductor  6  is welded and assembled on the face  11   b  of weld of the PCB board  11 . The special structures mentioned above bring the Chayote-like lamp advantages e.g., novel structure, ultra-short size, small and exquisite, higher luminous efficiency, higher reliability, longer service life and wide application for the illumination in all places, particularly suitable for the lamps and lanterns with covers. 
   The foregoing example is only used for the description of the present invention, other than the limit to the present invention. To those skilled in the art, variations or modifications can be made without departing from the spirit and the range of the present invention. Therefore, all equivalent technical solutions shall belong to the category of the present invention and shall be covered by the claims. 
   The following is a list of terms used herein and the identification numbers corresponding to such terms: 
   base  1   
   upper cover  2   
   lower cover  3   
   luminous tube combination or luminous tube  4  (of the lamp  18 ) 
   electronic ballast  5   
   current limiting inductor  6   
   finger-shaped unit luminous tube  7   
   connection bridge  8   
   filament  9   
   filament outlet  10   
   Printed Circuit Board (PCB)  11   
   power supply connecting wire  12   
   input junction point  13   
   output junction point  14   
   connection securing glue  15   
   center point  16  (of the base  1 ) 
   thread  17  (of the base  1 ) 
   Chayote-like lamp  18   
   gap  19