transparent plastics

[aljsk8]

what is the material that will offer the best light transmission(if i put an led behind the material i want the most light to pass through it)

out of

Clear Lexan (polycarbonate)
acrylic / perspex

are there any other clear plastics? i dont want to use glass

also what effect does the thickness have on light transmission

thanks

Alex

 

[LumenHound]

Those all have about a 92% maximum light transmittance in the visable light spectrum.
You can expect to find extruded sheets of all of them to have transmittance values between 85-90%.

 

[jhanko]

You pretty much summed up your choices.

Acrylic: It has slightly better light transmission than polycarbonate, but at thicknesses less than 1/4", they're both considered completely transparent. It maintains it's clairity over time. It passes UV light better. It's harder and more scratch resistant. It cracks and shatters much easier than polycarbonate.

Polycarbonate: It's flexible & impact resitant. It blocks almost all UV light. It turns yellow over time.

They both have their place. Which is "best" depends on the application.

 

[aljsk8]

thanks for the info

it is just to cover some bare leds to avoid damage its not a flashlight

it will just be a rectangular sheet bolted around 4 x mce leds
will be about a cm away from leds and id say about 5mm thick will be enough

it may fall over and hit concrete but the heads of bolts or nuts would probably contact the ground first

looking at ebay prices it will be easy to replace but obviously id rather it didnt break

 

[J_C]

Considering the potential for falls on concrete I'd definitely pick polycarbonate over acrylic unless there is a substantial amount of direct sunlight on it long term. Some polycarb products have UV protection, worthwhile to slow down yellowing.