Hello, how to narrow beam of flashlight with several leds? for exmaple TR-j12. will it work with one convex lens ? or it need 5 individual lenses ?
it wont work with a single aspheric as that produces a pattern that looks a bit like a biohazard symbol on the wall when used with a 3 emitter flashlight. I tried it with the dry and a 60mm Aspheric for kicks. Might be good for the zombie hunting crowd. (Kind of a biohazard batman symbol).
If i throw away a reflector and replace original glass with this ? http://www.dealextreme.com/p/59mm-20mm-15-120-degree-99-transmittance-glass-optic-13569
is there any other project with lenses and leds in internet ? i can't find any.
There is, you'd need 3 seperate aspherics. Search for Viffer750's work.
or 5, for the OPs question
what diameter and shape lens need for tr-j12??
The Ledil boomerang works well in multi-LED apps:
http://www.cutter.com.au/proddetail.php?prod=cut820
These look promising as well; I'm planning on ordering some with the next Cutter order:
ordered this http://www.dealextreme.com/p/12-5mm-mini-secondary-optics-plastic-20-pack-4588 will try to create something :D