The Original 5mm LED diode
The LED chip would have been no more than 0.5mm
New Type LED Array Announced
The University of Miami College of Engineering has just announced the development of a new type of LED light. This new approach is based on various of arrays consisting of many very very tiny individual diodes. The diodes are said to be some 100 times smaller than the current LED diodes.
Now given the average LED chip is less than half a millimeter across - these little diodes must be some .005 of a millimeter. At that size, it would take a good microscope to see one!!
Central to the development of these LEDs is detailed analysis of thermal management, that is how heat is handled by the array. Heat is what degrades or destroys LEDs, so good heat management will be a major advance.
The stated advantages of the new LEDs are that these arrays should operate at lower temperatures which would mean higher efficiency and longer life-span.