I just saw your post after playing with one of the free ray tracing packages (Optical Ray Tracer 9.6) that berkeman suggested (Thanks berkeman).
It really does show how TIR sends light into all directions, as you pointed out.
This is the best simulation I can muster given the constraints, and...
No, the light pipe is necessary to insert the light source to the proper location.
If I had some idea of the optically optimal shape of the top face to concentrate the emerging light into a reasonably narrow beam, then that would solve the problem.
The LED is a 3W SMD high power one and is mounted on an aluminium PCB for good heat dissipation.
I agree that you can get narrow angle through-hole ones, but they are low power.
I've already looked through Digi-Key and Mouser, but they all attempt to have a wide angle of visibility - the...
The intent is just to deliver as much of the light to a small area about the same distance from the exit as the light pipe's length (approx 25mm) away.
Uniformity is unimportant, as is visibility.
I am trying to design an acrylic light pipe that has a 3W power red LED input with 60 degree beam angle.
I need a reasonably collimated exit light beam or at least a narrow angle output.
What I'd like to know is - what is the optimum shape of the exit end of the light pipe to produce the...