About: http://webisa.webdatacommons.org/170681779

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	The sheet of optical material can have a curved surface, such as a lens.
http://www.w3.org/ns/prov#wasQuotedFrom	freepatentsonline.com