Surface Finish for Light Pipe Diffused Exit surface

[sgnpinoy]

Hi,

I am new to lightpipe design and just could not find any information on what kind of surface finish/texture of the area where light is supposed to exit (Diffused Exit surface)? I am aware the other areas are to be high;y polished. Can any one kindly elaborate or point to somewhere I can get some info?

Thanks so much

I had also posted this in the Plastic design/tooling engineering Forum since they are related.