High density multi-chip led devices

Abstract

High density multi-chip LED devices are described. Embodiments of the present invention provide high-density, multi-chip LED devices with relatively high efficiency and light output in a compact size. An LED device includes a plurality of interconnected LED chips and an optical element such as a lens. The LED chips may be arranged in two groups, wherein the LED chips within each group are connected in parallel and the groups are connected in series. In some embodiments, the LED device includes a submount, which may be made of ceramic. The submount may include a connection bus and semicircular areas to which chips are bonded. Wire bonds can be connected to the LED chips so that all the wire bonds are disposed on the outside of a group of LED chips to minimize light absorption.

1 . An LED device comprising:
 a plurality of interconnected LED chips; and   an optical element disposed to affect light from the LED chips;   wherein the optical element is less than 12 mm in diameter while maintaining a clearance between any of the LED chips and an edge of the optical element such that the clearance is from approximately 0.2 to 0.8 the width of the plurality of interconnected LED chips.   
     
     
         2 . The LED device of  claim 1  wherein the optical element is less than 10 mm in diameter. 
     
     
         3 . The LED device of  claim 2  wherein the clearance is from approximately 0.3 to 0.65 the width of the plurality of interconnected LED chips. 
     
     
         4 . The LED device of  claim 2  wherein the plurality of interconnected LED chips further comprises at least two groups of LED chips wherein the LED chips within each group are connected in parallel and the groups are connected in series. 
     
     
         5 . The LED device of  claim 4  wherein each group comprises six LED chips. 
     
     
         6 . The LED device of  claim 4  wherein at least one group of LED chips includes LED chips of at least two different sizes. 
     
     
         7 . The LED device of  claim 4  wherein each group comprises seven LED chips. 
     
     
         8 . The LED device of  claim 6  wherein one size of LED chips is about 1000 microns square and another size of LED chips is about 700 microns or less square. 
     
     
         9 . The LED device of  claim 4  wherein each group comprises eight LED chips. 
     
     
         10 . The LED device of  claim 6  wherein one size of LED chips is a vertical LED chip and another size of LED chips is a sideview LED chip. 
     
     
         11 . The LED device of  claim 1  sized to fit in an LED lamp with a form factor of an M16 halogen bulb. 
     
     
         12 . The LED device of  claim 1  where, when the LED chips are energized, the device emits light with an efficiency of at least 80 lm/W and a color rendering index of at least 80. 
     
     
         13 . The LED device of  claim 12  wherein the optical element is about 9.1 mm in diameter, the efficiency is at least about 95 lm/W and the CRI is at least 82. 
     
     
         14 . The LED device of  claim 13  where, when the LED chips are energized, the device emits light with an efficiency of at least 150 lm/W. 
     
     
         15 . An LED device comprising:
 a submount including a connection bus;   at least one group of LED chips fixed to the submount; and   a plurality of wire bonds, each connected between an LED chip and the submount, wherein at least some of the wire bonds are connected to the connection bus.   
     
     
         16 . The LED device of  claim 15  further comprising an optical element disposed to affect light from the LED chips. 
     
     
         17 . The LED device of  claim 16  wherein the at least one group of LED chips comprises two groups of LED chips, wherein the connection bus is a central bus, and wherein at least some of the wire bonds connected to the LED chips in each group are connected to the central bus. 
     
     
         18 . The LED device of  claim 17  wherein each group comprises eight LED chips. 
     
     
         19 . The LED device of  claim 17  wherein each group comprises six LED chips approximately equal in size. 
     
     
         20 . The LED device of  claim 17  wherein each group comprises seven LED chips approximately equal in size. 
     
     
         21 . The LED device of  claim 17  wherein at least one group of LED chips includes LED chips of at least two different sizes. 
     
     
         22 . The LED device of  claim 21  wherein one size of LED chips is about 1000 microns and another size of LED chips is about 700 microns or less.