On Tue, Mar 11, 2008 at 11:35 AM, Vasile Surducan wrote: > Coherent light is defined by energy at a known wavelenght, while non > coherent by a sum of energies at different wavelenght. You're confusing coherency with monochromaticity. Coherency is different. http://library.thinkquest.org/27356/d_coherentlight.htm > A LED has wavelenght disperssion of about 10-20nm , while a good laser > diode below 1nm in the worst situation. About the laser spot, that > depends on distance between the laser sourse and the target point. For this app, broad-fan illumination, say 100-ish degrees by 50-ish would be good. > Only you know what do you want... :) Most picture per milliwatt of illumination. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist