Abstract:
A light source may comprise a thermally conductive frame comprising a base and a faceted portion extending from the base. The faceted portion may comprise a plurality of facets spaced circumferentially thereabout. Additionally, a hollow passageway may extend through the base and axially through the faceted portion. A plurality of LED chips may be arranged on the plurality of facets to provide an emission of light in an arc of 360 degrees.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application is a continuation of U.S. patent application Ser. No. 12/785,203, filed May 21, 2010, which is a continuation of U.S. patent application Ser. No. 11/397,323, filed Apr. 4, 2006, now U.S. Pat. No. 7,728,345, which is a continuation-in-part of U.S. patent application Ser. No. 10/773,123, filed on Feb. 5, 2004, now abandoned, which is a continuation-in-part of U.S. patent application Ser. No. 09/939,339, filed on Aug. 24, 2001, now U.S. Pat. No. 7,224,001, the disclosures of each of which are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to the field of light sources for illuminating physical spaces and, more particularly, to light sources comprising one or more semiconducting light emitting diodes (LEDs). 
       BACKGROUND 
       [0003]    This disclosure pertains to light sources, such as light bulbs, for illuminating physical spaces. In particular, the difficulty of generating sufficient light with a light emitting diode (LED) light source to illuminate a physical space is addressed. In the past, LED lights were often restricted to serving as accent lighting due to insufficient light output. 
       SUMMARY 
       [0004]    A 3-dimensional multiple-faced lead frame is used to create a compact and efficient light source. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  depicts a perspective view of a light source for illuminating a physical space using a 3-dimensional multiple-faced lead frame; 
           [0006]      FIG. 2  depicts a cross-sectional view of the device of  FIG. 1 ; 
           [0007]      FIG. 3  depicts some example shapes for lead frame; 
           [0008]      FIG. 4  depicts a perspective view of an alternative light source using a 3-dimensional multiple-faced lead frame; 
           [0009]      FIG. 5  depicts a cross-sectional view of the device of  FIG. 4 ; 
           [0010]      FIG. 6  depicts a perspective view of another alternative light source using a 3-dimensional multiple-faced lead frame; 
           [0011]      FIG. 7  depicts a perspective view of another alternative light source using a 3-dimensional multiple-faced lead frame; and 
           [0012]      FIG. 8  depicts a cross-sectional view of the device of  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    There are several ways to increase LED output. One is to increase the size of the chips. Another is to utilize more chips in the light source. Increasing chip size creates several issues. First, it increases cost because production processes must be more precise as chip size increases. Second, the chip will have a lower emitting efficiency due to heat issues. When an LED chip is enlarged, heat is also proportionally increased. Large amount of heat are not easily removed from the chip, therefore, the overall temperature of the chip will be increased and light emitting efficiency will decrease. 
         [0014]    In the prior art, multiple LED chips were integrated together in 2 dimensional plate form to achieve an increase in power. Integration of multiple chips in a 2 dimensional array also has disadvantages of a large footprint and a complicated production process. This disclosure relates to structures and processes for creating an LED light source using a 3-dimensional multiple facet lead frame to create a compact and efficient light source. 
         [0015]      FIG. 1  depicts an LED light source  100  having a 3-dimensional lead frame with multiple facets or faces to house multiple LED chips. A 3 dimensional lead frame  101  is provided with a shaft  102  and a standard screw thread  103 . With the thread, the light source can be twisted into a traditional light socket to replace prior art incandescent bulbs. Faces or facets  104  are provided on the lead frame  101 . The lead frame  101  itself acts as cathode for the LED  100 . A cap  105  of the anode is provided with an extended pin  106 . The cathode and anode are isolated by an insulation layer  107 . The LED chip(s)  108  are placed on each facet of the lead frame  101 . One or more chips per facet or face can be used. A wire  109  connects the anode of the chip  108  to the anode  105  of the lead frame and wire  110  connects the cathode of the chip to the main body of the lead frame. The lead frame with chips is covered by an epoxy cap  120 . The epoxy cap  120  acts as optical lens for light emitted from chip and also as protection layer for the chip and lead frame. The overall design achieves the following features for a light source: emission of light in an arc of 360 degrees; the light source is easily replaceable, and the light source is completely sealed and water proof. 
         [0016]      FIG. 2  depicts cross section  200  of the LED described in  FIG. 1 . Lead frame  201  is shown in cross section. Base  202  is the cathode of the LED, and the shaft  203  of the cathode connects to a threaded fitting  204 . The facet portion  205  of the cathode is almost perpendicular to the base  202  in this example. Based on design requirements, the facet may not be perpendicular to the base. Cap  206  of the anode of the lead frame has a pin  207  extending through cathode of lead frame. The anode and cathode are isolated by an insulation material  208 . The insulation material can be epoxy, AlO, and any other materials having insulation properties. The insulation layer will electrically insulate the anode and cathode. Chips such as  209  are attached to facets of the lead frame. Chip  209  is connected to anode  206  using wire  210   a  and is connected to cathode  201  using gold or Al wire  210   b.  There is a light conversion layer  211  coated on top of chip  209  to convert the emitted from the chip into different color when such conversion is required. The lead frame, anode, cathode and chips are covered by an epoxy cap  212 . The epoxy cap  212  acts as both optical lens and also as a protection layer for lead frame and chips. 
         [0017]      FIGS. 3   a - 3   f  depict example profiles for a lead frame. The main shape of the lead frame is defined by the shape of cathode. The anode has the same shape as cathode and both can be any shape as desired.  FIG. 4  depicts a multiple facet LED with a surface mount type package  400 . A base  401  is provided that acts as a heat conductor. It can be made from electrically insulating material, such as ceramics, plastics, etc. On the base  401 , electrodes  402  and  403  are laid on one side of the base and electrodes  404  and  405  are laid on the other side the base. Anodes  402  and  404  are also provided to complete the circuit with cathodes  403  and  405 . Electrodes may be made by coating a metal layer like Al or Au or other alloys on top of a ceramic base. On top of the  401  base, there sits a cathode  407  of lead frame  406 . The cathode  407  of lead frame  406  is connected to base  401 . There are multiple vertical facets  408  connected to base  407 . The anode cap  409  is placed on top of the cathode lead frame with an insulation layer  410  in between. A chip  411  is laid on one of the facets. The chip  411  is connected to cathode and anode through wires  412  and  413 . The lead frame and chips are capped with epoxy layer  414 , which will serve as a cap and also as an optical lens. Options include a surface mount type as well as a printed circuit board with various electronics. 
         [0018]      FIG. 5  depicts a cross-sectional view of an LED  500  such as that already discussed with respect to  FIG. 4 . A lead frame cathode  501  is provided with a base  502 . A cap  504  is provided as well as an anode pin  505 . An insulation layer  506  is located between the cathode and anode. An LED chip  507  is located on one of the frame faces such as  503 . An optional phosphor coating layer  508  may be used for light color conversion. Wires  509  and  510  connect the chip to anode and cathode. An epoxy cap  511  covers the whole lead frame. The base profile of the LED is shown at  512 . The material for base  512  has a property for heat conduction and electrical insulation. Electrodes are laid using metal coating layers  513  and  514  for cathode and anode, respectively. The cathode  503  of the lead frame is connected to cathode  513  in the base through connection  515  and anode  505  of the lead frame is connected to anode in the base  514  through connection  516 . 
         [0019]      FIG. 6  depicts another packaging style with light only emitted in one direction. Note the fewer faces on the frame. The LED  600  has a base  601  and electrodes  602 ,  603 ,  604 , and  605  respectively. The lead frame  606  only has multiple facets in one direction and chips are placed on the facet. There is an epoxy cap  607  to protect the lead frame and LED chips. The light will be emitted in one direction. Such light can be used for different backlighting applications. 
         [0020]      FIG. 7  depicts a cylinder style of two multiple face lead frames connected to each other. LED  700  has two cathode lead frames  701  and  702  with multiple facets. One anode  703  is placed to next to cathode  701  with insulation layer  704 . A chip  705  is placed on one of facets with wire connections to anode and cathode. Another anode  706  which is sandwiched by two insulation layers  708  and  709  is placed between frames  701  and  702 . LED chip  709  is placed on top of one of faces in  702 . An epoxy cap  711  is molded to cover the whole lead frame and components. Electrodes  712  and  713  are set up as the leads for anode and cathode, respectively. 
         [0021]      FIG. 8  depicts a cross sectional view of the LED illustrated in  FIG. 7 . This view shows the arrangement between anode and cathode. In the anode, there is a contact  801 . Platforms  802  and  803  connected by a rod  804 . There are two bonding facets  805  and  806  on platforms  802  and  803 , respectively. Two cathodes  807  and  808  with multiple facets are connected through connection rod  809 . Insulation layers  810  and  811  are used to fill the space between anode and cathode. The contact for cathode is  812 . A chip  813  is mounted on a facet of the lead frame. An optional phosphor coating  814  can provide wavelength conversion. Wires  815  and  816  connect the chip to anode and cathode. 
         [0022]    A light source with a multiple faceted lead frame with LED chip(s) attached to each facet can be provided to integrate multiple chip(s) into one small foot print package. The number of facets on the lead frame can be one to infinity depending on requirements. The lead frame is a 3-dimensional device with facets angled in desired directions. Cathode and anode of the lead frame isolated with insulation materials. One or more LED chips can be attached to each facet. A light conversion layer may be coated on top of LED chips to convert the color of the light emitted by the chips. The lead frame is covered by an epoxy capsule as both protection and optical lens. The lead frame can be a diode type with a thread on the base or surface mount type with electrodes on the base. The multiple faceted lead frame can be one section or multiple sections to form a bar type of light source. A white light source with multiple facet lead frame by applying a phosphor on top of a blue chip. The lead frame is made from a heat conducting material in order to draw heat away from the chips and avoid loss of lumen output due to heat effect. 
         [0023]    While the present invention has been described and illustrated in conjunction with a number of specific embodiments, those skilled in the art will appreciate that variations and modifications may be made without departing from the principles of the invention as herein illustrated, described, and claimed. The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects as only illustrative, and not restrictive. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.