About: http://webisa.webdatacommons.org/388740251

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Such a Fresnel lens is preferably made of a synthetic resin, for example PMMA or PC. To avoid lens errors, the projection lens is preferably embodied so as to be an aspherical lens.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com