[time-nuts] White LED's

[Magnus Danielson]

Robert Atkinson wrote:
> Hi,I'm late to the thread (as usual), but have looked at these LED's in the past. It was for a biotech imaging application. There are two types, a red/green/blue cluster or a blue / near UV LED with a white phosphor. These phosphors seem to have a fairly continuous spectrum, at least compared to fluorescent lamps and HID lamps. What surprised me was the speed. We had a strobe application for which a xenon strobe was proposed. I tried LED's (our optics "expert" said even normal LED's would not be fast enough). I knew normal LED's are fast enough but was unsure about the phosphor types. To my surprise they where faster than the xenon tube! They were faster than my detector. This has has an impact on the mill illumination in that you can get strobe effects that could cause you to think the spindle was stationary when it was not. This is more of a problem in a noisy environment than a home shop with only one machine running.  

Traditional LEDs might not be optimized for speed, bug being GaAsP based 
they are probably not too shabby. InP and other fun (and fast) materials 
is used. Digging up on LEDs led me over YAG to bubble memories.

Interesting side-effects of this discussion is that one learns more in 
fields one does not ponder too much over normally.

Cheers,
Magnus