Bendable sheet of plastic that intensifies heat from sun?

Question

I saw this on a solar panel website one time but am now unable to locate. It's a thin sheet of what appears to be plastic but it isn't clear... it's more opaque than anything. What the site claimed was that by shining the sun through this plastic (like shining the sun through a magnifying glass) you can intensify to some (great) degree onto a particular area. Anyone ever heard of it? Does this type of material exist? Is it a scam? Any information appreciate.

Answer 1

sounds like a fresnel lense