said membrane having formed therein {HEAD ~ a pleated structure} surrounding said contact region and defining {TAIL ~ a bellows portion} for increasing a displacement distance of said contact region of said membrane 
defining
said membrane having formed therein { HEAD ~ a pleated structure } surrounding said contact region and defining { TAIL ~ a bellows portion } for increasing a displacement distance of said contact region of said membrane
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH