Anyone here an automotive headlight engineer?


Newly Enlightened
Oct 5, 2016
Acrylic isn't used for headlamps because it is much more easily damaged than polycarbonate. It's inherent UV resistance is better than polycarbonates, sure, but its refracrive index is likely different as well, which could effect the beam pattern and intensity.

Edit- I remember reading something in the automotive subforum about polycarbonate alternatives that were being tested in the EU, grilamid is a name that sticks out in my mind. I believe it was a UV stable plastic of similar mechanical properties to polycarbonate.
Acrylic is fine to use for the face plate. Its actually clearer by a few percent than Lexan and the refraction won't affect the pattern. The reason why the auto manufacturers use polycarbonate is because its very strong and they wanted assurance. But acrylic will be fine for my application. Poly and Acrylic both scratch very easily. And since this is an DIY, working with acrylic is much easier since poly is a super tough material. One needs heavy duty power tools to work and shape Lexan. The acrylic sheet thickness I'm working with is .093


Flashlight Enthusiast
Feb 20, 2009
While I hate to point you somewhere off this forum, there is a poster "Yoshi I" on Tacomaworld . Com who is apparently someone related to Morimoto. He has posted in response to some discussion about fog/driving lights and has provided beam iso-plots showing how aim effects beam pattern appearance.