Patent Publication Number: US-2007103904-A1

Title: Light emitting diode lamp

Description:
BACKGROUND AND SUMMARY OF THE INVENTION  
      The present invention relates to lamps and more particularly, to a light emitting diode lamp, which comprises a lamp base, a bulb fastened to the lamp base, and a light emitting diode lamp voltage-dropping circuit module mounted inside the lamp base and holding a light emitting diode close to the bottom end of the bulb to prevent an illumination dead angle, allowing the light emitted by the light emitting diode to pass to the outside through the whole area of the bulb.  
       FIGS. 1 and 2  show a conventional light emitting diode lamp  6 . The light emitting diode lamp  6  comprises a lamp base  61 , a bottom bulb shell  602  fastened to the lamp base  61 , a circuit board  62  mounted inside the bottom bulb shell  602  and electrically coupled to the threaded ring contact  611  and tip contact (not shown) of the lamp base  61 , a light emitting diode  63  installed in the circuit board  62 , and top bulb shell  601  fastened to the bottom bulb shell  602 . According to this design, the threaded ring contact  611  of the lamp base  61  can be fastened to a conventional lamp socket  7  for Christmas tree light string (see  FIG. 3 ) or a conventional lamp socket and plug assembly  8 . This light emitting diode lamp  6  may be decorated with a lamp-shaped ornament  80  before installation in a conventional lamp socket and plug assembly  8 . After connection of the lamp-shaped ornament  80  to the light emitting diode lamp  6 , the threaded ring contact  611  of the lamp base  61  extends out of the bottom opening  801  of the lamp-shaped ornament  80  for fastening to the lamp socket and plug assembly  8 . This design of light emitting diode lamp  6  is still not satisfactory in function because of the following drawbacks:  
      1. Because the body  630  of the light emitting diode  63  is suspending in the center area in the holding space surrounded by the bottom bulb shell  602  and the top bulb shell  601 , the circuit board  62  blocks the light of the light emitting diode  63  from passing to the outside through the bottom bulb shell  602 .  
      2. The circuit board  62  has installed therein related electronic component parts such as capacitor  621 , resistor  622  and voltage stabilizing diode  623 . These electronic component parts  621 ,  622 ,  623  block a part of the light of the light emitting diode  63 , thereby lowering the brightness of the light emitting diode lamp  6 .  
      3. Because the bottom bulb shell  602  and the top bulb shell  601  are transparent, the electronic component parts  621 ,  622 ,  623  are visible from the outside, i.e., the visible electronic component parts  621 ,  622 ,  623  destruct the sense of beauty of the light emitting diode lamp  6 .  
      Mounting the electronic component parts  621 ,  622 ,  623  in the bottom side of the circuit board  62  can eliminate the aforesaid second and third drawbacks. However, because the lamp base  61  has many different specifications in different countries, for example, E26, E17 and E12 in USA and Canada, E27, E14 and E10 in West Germany and some other European countries. According to E12, the lamp base has an outer diameter about 12 mm and an inner diameter about 10 mm. According to E10, the lamp base has an outer diameter about 10 mm and an inner diameter about 8 mm. The limited inside space of the lamp base provides no room for so many electronic component parts  621 ,  622 ,  623 .  
       FIG. 6  shows another design of light emitting diode lamp  9  according to the prior art. According to this design, the light emitting diode lamp  9  comprises a bulb  90 , a lamp base  91 , a holder frame  94  joining the bulb  90  and the lamp base  91 , a circuit board  92  mounted inside the holder frame  94 , and a plurality of light emitting diodes  93  installed in the circuit board  92 . The circuit board  92  has the related electronic component parts including capacitor  921 , resistor  922  and voltage stabilizing diode  923  mounted in the bottom side. Therefore, these electronic component parts  921 ,  922 ,  923  do not block the light of the light emitting diodes  93  or are kept from sight by the holder frame  94 . However, this design of light emitting diode lamp  9  still has drawbacks as follows:  
      1. It wastes much time and labor to join the holder frame  94 , the bulb  90  and the lamp base  91 .  
      2. Because the holder frame  94  does not admit light, it blocks a part of the light emitted by the light emitting diodes  93 , lowering the brightness of the light emitting diode lamp  9 .  
      3. An extra molding mold is necessary for molding the holder frame  94 , increasing the manufacturing cost of the light emitting diode lamp  9 .  
      The present invention has been accomplished under the circumstances in view. According to one aspect of the present invention, the light emitting diode lamp comprises a lamp base connectable to a lamp socket, a bulb fastened to the top side of the lamp base, a light emitting diode lamp voltage-dropping circuit module, and a light emitting diode installed in the top side of the light emitting diode lamp voltage-dropping circuit module. The light emitting diode lamp voltage-dropping circuit module is fixedly mounted in the holding space inside the lamp base, and the light emitting diode is kept close to the bottom end of the bulb to prevent an illumination dead angle, allowing the light emitted by the light emitting diode to pass to the outside through the whole area of the bulb. According to another aspect of the present invention, there is no other electronic component parts provided above the elevation of the topmost edge of the lamp base except the light emitting diode, therefore the light emitting diode lamp causes a sense of beauty and, the light emitted by the light emitting diode passes through the whole area of the bulb to the outside, providing a high brightness. According to still another aspect of the present invention, the light emitting diode lamp voltage-dropping circuit module has a small size and can be installed in the holding space inside the lamp base, which is made subject to any of a variety of specifications. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       FIG. 1  is a perspective view of a light emitting diode lamp according to the prior art.  
       FIG. 2  is a sectional view of the light emitting diode lamp shown in  FIG. 1 .  
       FIG. 3  illustrates the use of the prior art light emitting diode lamp of  FIG. 1  with a conventional lamp socket for Christmas tree light string.  
       FIG. 4  illustrates the use of the prior art light emitting diode lamp of  FIG. 1  with a conventional lamp socket and plug assembly.  
       FIG. 5  illustrates the prior art light emitting diode lamp of  FIG. 1  decorated with a lamp-like ornament for use with a conventional electric socket and plug assembly.  
       FIG. 6  is a sectional view of another design of light emitting diode lamp according to the prior art.  
       FIG. 7  is a perspective view of a light emitting diode lamp according to the present invention.  
       FIG. 8  is a sectional view of the light emitting diode lamp according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to  FIGS. 7 and 8 , a light emitting diode lamp in accordance with the present invention is shown comprising a lamp base  2 , a bulb  1  fastened to the top end of the lamp base  2 , and a light emitting diode  3  mounted in the lamp base  2  and suspending in the bulb  1 . The lamp base  2  is a hollow cylindrical member having a bottom wall  21 , a peripheral wall  22  extending around the periphery of the bottom wall  21 , an outer thread  221  extending around the peripheral wall  22  for fastening to a lamp socket (not shown), a negative electrode  42  installed in the peripheral wall  22 , and a positive electrode  41  installed in the center of the bottom wall  21 .  
      Referring to  FIG. 8  again, the light emitting diode  3  is installed in a light emitting diode lamp voltage-dropping circuit module  4 , which is mounted in the holding space  20  inside the lamp base  2  and adapted to drop the input voltage to a suitable voltage level for the light emitting diode  3 . Further, the light emitting body  31  of the light emitting diode  3  is kept close to the bottom end of the bulb  1 . Therefore, the light emitted by the light emitting body  31  of the light emitting diode  3  pass to the outside through the whole area of the bulb  1 . Because there is no any other electronic component parts above the topmost edge  23  of the lamp base  2 , the light emitted by the light emitting body  31  of the light emitting diode  3  pass through the whole area of the bulb  1  to the outside. Therefore, the light emitting diode lamp has a high brightness. Further, because the light emitting diode lamp voltage-dropping circuit module  4  has a small size, it can be installed in the holding space  20  inside the lamp base  2 , which is made subject to any of a variety of specifications such as E26, E17 and E12 in USA and Canada, E27, E14 and E10 in West Germany and some other European countries.  
      Further, the aforesaid positive electrode  41  and negative electrode  42  are respectively electrically connected to the positive and negative terminals of the light emitting diode lamp voltage-dropping circuit module  4 .  
      In the aforesaid embodiment, only one light emitting diode  3  is installed in the voltage-dropping circuit module  4 . Alternatively, multiple light emitting diodes  3  can be used and installed in the voltage-dropping circuit module  4  to increase the brightness of the light emitting diode lamp. Further, the light emitting diode  3  can be a chip light emitting diode.  
      Further, the aforesaid light emitting diode lamp voltage-dropping circuit  4  comprises a circuit board (not shown), and the aforesaid light emitting diode  3  and an integrated circuit (not shown) installed in the circuit board.  
      As indicated above, the invention provides a light emitting diode lamp, which has the following features:  
      1. The light emitting diode  3  is installed in the top side of the light emitting diode lamp voltage-dropping circuit module  4 , which is fixedly mounted in the holding space  20  inside the lamp base  2 , and the light emitting body  31  of the light emitting diode  3  is kept close to the bottom end of the bulb  1  to prevent an illumination dead angle, allowing the light emitted by the light emitting body  31  of the light emitting diode  3  to pass to the outside through the whole area of the bulb  1 .  
      2. Except the light emitting diode  3 , there is no other electronic component parts provided above the elevation of the topmost edge  23  of the lamp base  2 , therefore the light emitting diode lamp causes a sense of beauty and, the light emitted by the light emitting diode  3  passes through the whole area of the bulb  1  to the outside, providing a high brightness.  
      3. The light emitting diode lamp voltage-dropping circuit module  4  has a small size and can be installed in the holding space  20  inside the lamp base  2 , which is made subject to any of a variety of specifications.