Fresnel lens were invented in the 1700's by a Frenchman with a similar sounding last name.  These lens were first used in lighthouses as a way of detracting lens into a wider area across the seas so that merchant ships could find their way into the channel & port at night.

Fresnel lens have a top smooth side and an under side that has groves laid out in a specific order of ridges.  When these ridges are exposed to light they end up magnifying a viewing surface.