Flexible interconnect structures for electrical devices and light sources incorporating the same

Abstract

A flexible interconnect structure allows for rapid dissipation of heat generated from an electrical device that includes light-emitting elements, such as light-emitting diodes (“LEDs”) and/or laser diodes. The flexible interconnect structure comprises: (1) at least one flexible dielectric film on which circuit traces and, optionally, electrical circuit components are formed and at least a portion of which is removed through its thickness; and (2) at least a heat sink attached to one surface of the flexible dielectric film opposite to the surface on which circuit traces are formed. The flexible interconnect structure can include a plurality of such flexible dielectric films, each supporting circuit traces and/or circuit components, and each being attached to another by an electrically insulating layer. Electrical devices or light sources having complex shapes are formed from such flexible interconnect structures and light-emitting elements attached to the heat sinks so to be in thermal contact therewith.

1 . A bendable electromagnetic radiation emitting semiconductor dice array comprising: 
 a plurality of metal heat spreaders;    at least one dielectric layer disposed above a first portion of each of the underlying plurality of metal heat spreaders, creating a first portion of a plurality of openings, each opening disposed over a corresponding metal heat spreader;    a bendable electrical interconnection layer disposed above a first portion of the at least one dielectric layer and creating a second portion of each said opening disposed over a corresponding metal heat spreader, wherein said bendable electrical interconnection layer comprises a plurality of electrical current pathways; and    a plurality of electromagnetic radiation emitting semiconductor dice, wherein each of the dice is mounted over a corresponding one of the plurality of metal heat spreaders with a corresponding thermal conduction means that provides a direct thermal pathway from the die to the underlying metal heat spreader, and wherein each die is electrically coupled to the bendable electrical interconnection layer.    
   
   
       2 . The bendable electromagnetic radiation emitting semiconductor dice array of  claim 1 , wherein said plurality of electromagnetic radiation emitting semiconductor dice comprises diodes selected from the group consisting of light emitting diodes (LEDs), ultraviolet emitting diodes, and laser diodes, and wherein each of the dice comprises a first electrical contact and a second electrical contact, said first electrical contact and said second electrical contact electrically coupled to separate pathways of said plurality of electrical current pathways.  
   
   
       3 . The bendable electromagnetic radiation emitting semiconductor dice array of  claim 1 , wherein each of said thermal conduction means comprises a thermally conductive adhesive.  
   
   
       4 . The bendable electromagnetic radiation emitting semiconductor dice array of  claim 1 , wherein said bendable electrical interconnection layer comprises a component selected from the group consisting of bendable printed circuit boards, flexible printed circuit boards, flex circuits, and metal lead frames.  
   
   
       5 . The bendable electromagnetic radiation emitting semiconductor dice array of  claim 1 , wherein said plurality of metal heat spreaders comprise metal with high thermal conductivity.  
   
   
       6 . The bendable electromagnetic radiation emitting semiconductor dice array of  claim 1 , wherein at least one die of said plurality of electromagnetic radiation emitting semiconductor dice is thermally coupled to each heat spreader of said plurality of metal heat spreaders.  
   
   
       7 . The bendable electromagnetic radiation emitting semiconductor dice array of  claim 1 , wherein at least one heat spreader of said plurality of metal heat spreaders comprises an optically reflective surface disposed to reflect light emitted by at least one die of said plurality of electromagnetic radiation emitting semiconductor dice.  
   
   
       8 . The bendable electromagnetic radiation emitting semiconductor dice array of  claim 1 , wherein said plurality of metal heat spreaders are thermally coupled to a heat sink.  
   
   
       9 . The bendable electromagnetic radiation emitting semiconductordice array of  claim 1 , wherein each heat spreader of said plurality of metal heat spreaders is structurally coupled to an adjacent heat spreader of said plurality of metal heat spreaders via at least one bendable interconnection member disposed therebetween.  
   
   
       10 . The bendable electromagnetic radiation emitting semiconductor dice array of  claim 1 , further comprising at least one optically transmissive material disposed around at least one die of said plurality of electromagnetic radiation emitting semiconductor dice to form at least one housing for said at least one die.  
   
   
       11 . The bendable electromagnetic radiation emitting semiconductor dice array of  claim 1 , wherein at least one heat spreader of said plurality of metal heat spreaders comprises an upper portion elevated above said bendable electrical interconnection layer and disposed through a corresponding opening of said plurality of openings, and wherein at least one of the dice of said plurality of electromagnetic radiation emitting semiconductor dice is disposed above and thermally coupled to the upper portion of the corresponding heat spreader.  
   
   
       12 . A bendable electromagnetic radiation emitting semiconductor dice array comprising: 
 a bendable metal frame comprising a plurality of metal heat spreaders and a plurality of bendable electrical current pathways;    at least one dielectric material disposed between each heat spreader of said plurality of metal heat spreaders and at least one pathway of said plurality of bendable electrical current pathways; and    a plurality of electromagnetic radiation emitting semiconductor dice, wherein each of the dice is mounted above a portion of the corresponding heat spreader's top surface with a corresponding thermal conduction means that provides a direct thermal path from the die to the corresponding heat spreader, and wherein each of the dice is electrically coupled to at least two pathways of said plurality of bendable electrical current pathways; and wherein a heat transfer surface of each heat spreader of said plurality of metal heat spreaders has a greater surface area than the bottom surface of each die of said plurality of electromagnetic radiation emitting semiconductor dice.    
   
   
       13 . The bendable electromagnetic radiation emitting semiconductor dice array of  claim 12 , wherein at least one heat spreader of said plurality of metal heat spreaders is thicker than at least one pathway of said plurality of bendable electrical current pathways, and wherein each of the dice comprises a first electrical contact and a second electrical contact, said first electrical contact and said second electrical contact electrically coupled to separate pathways of said plurality of bendable electrical current pathways.  
   
   
       14 . The bendable electromagnetic radiation emitting semiconductor dice array of  claim 12 , wherein at least one heat spreader of said plurality of metal heat spreaders comprises a heat spreading region that widens as the distance from the die mounted above that heat spreader increases, and wherein each of the dice comprises a first electrical contact and a second electrical contact, said first electrical contact and said second electrical contact electrically coupled to separate pathways of said plurality of bendable electrical current pathways.  
   
   
       15 . The bendable electromagnetic radiation emitting semiconductor dice array of  claim 12 , wherein at least one heat spreader of said plurality of metal heat spreaders is structurally attached to a corresponding electrical current pathway of said plurality of bendable electrical current pathways via an electrically conductive adhesives, and wherein each of the dice comprises a first electrical contact and a second electrical contact, said first electrical contact and said second electrical contact electrically coupled to separate pathways of said plurality of bendable electrical current pathways.  
   
   
       16 . The bendable electromagnetic radiation emitting semiconductor dice array of  claim 12 , further comprising a heat sink thermally coupled to said plurality of metal heat spreaders, and wherein each of the dice comprises a first electrical contact and a second electrical contact, said first electrical contact and said second electrical contact electrically coupled to separate pathways of said plurality of bendable electrical current pathways.  
   
   
       17 . A method of assembling a bendable electromagnetic radiation emitting semiconductor dice array comprising: 
 providing a bendable electrical interconnection layer;    attaching a plurality of heat spreaders to the bendable electrical interconnection layer via at least one adhesive dielectric layer, wherein a portion of a first surface of each heat spreader is exposed;    attaching a plurality of electromagnetic radiation emitting semiconductor dice to said plurality of heat spreaders by mounting each die of said plurality of electromagnetic radiation emitting semiconductor dice to the exposed portion of the first surface of a corresponding heat spreader via a corresponding thermal conductor; and    electrically coupling each die of said plurality of electromagnetic radiation emitting semiconductor dice into a functional electrical circuit configuration via said bendable electrical interconnection layer.    
   
   
       18 . The method of providing a dice array of  claim 17 , wherein each said thermal conductor comprises a thermally conductive adhesive.  
   
   
       19 . The method of providing a dice array of  claim 17 , wherein said bendable electrical interconnection layer comprises a component selected from the group consisting of bendable printed circuit boards, flexible printed circuit boards, flex circuits, and metal lead frames.  
   
   
       20 . The method of providing a dice array of  claim 17 , further comprising the step of bending the bendable electrical interconnection layer into a 3 dimensional configuration.  
   
   
       21 . The method of providing a dice array of  claim 17 , further comprising the step of thermally coupling said plurality of heat spreaders to a heat sink for enhanced heat dissipation.  
   
   
       22 . The method of providing a dice array of  claim 17 , further comprising the step of providing at least one optically transmissive material around at least one of the dice to form at least one housing.  
   
   
       23 . A method of providing a bendable electromagnetic radiation emitting semiconductor dice array comprising: 
 providing a bendable lead frame structure, wherein said bendable lead frame structure comprises a plurality of predefined metal heat spreader regions and a plurality of predefined bendable metal electrical current pathways;    attaching a plurality of electromagnetic radiation emitting semiconductor dice to said plurality of predefined metal heat spreader regions by mounting each of the dice to a corresponding one of the predefined metal heat spreader regions via a corresponding thermal conductor; and    electrically coupling each die of said plurality of electromagnetic radiation emitting semiconductor dice into a functional electrical circuit configuration via at least two pathways of said plurality of predefined bendable metal electrical current pathways.    
   
   
       24 . The method of providing a dice array of  claim 23 , further comprising the step of bending said bendable lead frame structure into a 3 dimensional configuration.  
   
   
       25 . The method of providing a dice array of  claim 23 , further comprising the step of thermally coupling said plurality of predefined metal heat spreader regions to a heat sink for enhanced heat dissipation.  
   
   
       26 . The method of providing a dice array of  claim 23 , further comprising the step of providing at least one optically transmissive material around at least one of the dice to form at least one housing.