Solid State Light Sheet Having Wide Support Substrate and Narrow Strips Enclosing LED Dies in Series

Abstract

A solid state light sheet and method of fabricating the sheet are disclosed. In one embodiment, bare LED chips have top and bottom electrodes, where the bottom electrode is a large reflective electrode. The bottom electrodes of an array of LEDs (e.g., 500 LEDs) are bonded to an array of electrodes formed on a flexible bottom substrate. Conductive traces are formed on the bottom substrate connected to the electrodes. A transparent top substrate is then formed over the bottom substrate. Various ways to connect the LEDs in series are described along with many embodiments. In one method, the top substrate contains a conductor pattern that connects to LED electrodes and conductors on the bottom substrate.

1 - 20 . (canceled) 
     
     
         21 . An illumination device comprising:
 a light-emitting element, the light-emitting element comprising:
 a non-packaged light-emitting diode (LED) die having a top electrode and a bottom electrode formed on opposite surfaces of the LED die; 
 a cup including an indentation, the indentation having substantially the same height as the LED die and at least a reflective surface, wherein the LED die is disposed in the indentation; 
   a transparent top substrate having a first surface and a second surface opposing the first surface, wherein the first surface of the top substrate faces the light-emitting element; and   first electrical conductors disposed on the first surface of the top substrate such that the top electrode of the LED die is in contact with the first electrical conductors, wherein the first electrical conductors are configured to provide power to the LED die.   
     
     
         22 . The illumination device of  claim 21 , further comprising:
 a bottom substrate having a third surface; and   second electrical conductors disposed on the third surface of the bottom substrate such that the bottom electrode of the LED die is coupled to the second electrical conductors, wherein the second electrical conductors are configured to provide power to the LED die.   
     
     
         23 . The illumination device of  claim 22 , wherein the cup is dielectric. 
     
     
         24 . The illumination device of  claim 23 , further comprising a conductive via formed through an opening in the cup such that the conductive via is in contact with the bottom electrode of the LED die and the second electrical conductors of the bottom substrate. 
     
     
         25 . The illumination device of  claim 22 , wherein the bottom substrate is transparent and the illumination device further comprises a reflective layer coupled to the bottom substrate. 
     
     
         26 . The illumination device of  claim 22 , comprising a plurality of light-emitting elements like the light-emitting element. 
     
     
         27 . The illumination device of  claim 26 , wherein at least a portion of the plurality of light-emitting elements are connected in series through the first and second conductors. 
     
     
         28 . The illumination device of  claim 21 , further comprising a light conversion layer coupled with the transparent top substrate. 
     
     
         29 . The illumination device of  claim 28 , wherein the light conversion layer is coupled to the second surface of the transparent top substrate. 
     
     
         30 . The illumination device of  claim 28 , wherein the light conversion layer is coupled to the first surface of the transparent top substrate. 
     
     
         31 . The illumination device of  claim 28 , wherein the transparent top substrate comprises the light conversion layer. 
     
     
         32 . The illumination device of  claim 28 , wherein the light conversion layer comprises phosphor. 
     
     
         33 . The illumination device of  claim 28 , wherein coverage of the conversion layer is configured to allow a portion of light emitted by the LED die to be output through the transparent top substrate without passing through the conversion layer. 
     
     
         34 . The illumination device of  claim 21 , further comprising an optical layer coupled to the transparent top substrate. 
     
     
         35 . The illumination device of  claim 34 , wherein the optical layer comprises a pattern to create a desired illumination pattern. 
     
     
         36 . The illumination device of  claim 35 , wherein the pattern comprises at least one of a lens, diffuser, or collimator. 
     
     
         37 . The illumination device of  claim 21 , wherein the reflective surface comprises a reflective coating. 
     
     
         38 . The illumination device of  claim 21 , wherein the indentation of the cup is conical. 
     
     
         39 . The illumination device of  claim 21 , wherein the indentation of the cup is parabolic. 
     
     
         40 . The illumination device of  claim 21 , further comprising an encapsulant encapsulating the LED die. 
     
     
         41 . The illumination device of  claim 40 , wherein the encapsulant comprises phosphor. 
     
     
         42 . The illumination device of  claim 21 , wherein the LED die is coated with a light conversion material. 
     
     
         43 . The illumination device of  claim 21 , wherein the transparent top substrate comprises phosphor.