What is a good LED light diffuser? Similar to the ring on Amazon Echo

Hi all,

I’ve been stuck for a while trying to find a good material and examples for diffusing LED lights. We have a board with 6 small (2 mm x 2 mm) LEDs on it. I want to make these look like a line instead of 6 single light dots! What material do you guys recommend? Any techniques? Thank you!

​