Moore's Law for LED flashlights ?

Okay I have searched but can't find...

I am wondering about the parallels between LED development and transistors on an integrated circuit. Obviously LEDs (like transistors) are going through an amazing development literally day by day it seems. Now I am no engineer so I am wondering what others views on this are... not fantasy but real educated guesses as to what is possible in terms of output and efficiency in years to come?

It would also be really interesting to consider the limits (like the size limitation for transistors that Moore thinks we will reach sometime in the not to distant future) - would this mean that a single AA sized LED pushing 1000 lumens for 24 hrs (as an example) in 15 years time will be as far as we can go? To go further would mean bigger emitters or power sources?

Maybe. In the case of computers we've been in a place for quite a while where Moore's Law's numbers would seem to be holding up -- at first glance, anyway. While computers have continued, "...to double in power every 12-18 months..." it has less and less to do with continuing transistor shrinkage as it is more about improving other facets of the machine.

So IMO it is unlikely that LEDs will see infinite improvement merely because of smaller transisters alone but as with CPUs, everything about LEDs is NOT known, making it likely that related improvements will continue at some pace.

LEDs are ultimately limited by the efficiency with which they can turn electrical energy into light.

This is measured in Lumens per Watt, and LEDs are already pretty darn good at it. The Cree XP-G for instance runs at around 130 Lumens per Watt.

The theoretical maximum for any light source (where all the energy is turned into photons) is 683 Lumens per Watt. There are good reasons (phosphor efficiency etc.) for thinking that white LEDs might ultimately be limited to a bit less than half of this.

So we're much closer to the theoretical limits than in other areas of electronics. We can perhaps expect an improvement of around 50% in the next few years, but we won't be getting a Moore's-Law type of increase with LEDs.