A preferable metal foil is of aluminum or stainless steel in {HEAD ~ a thickness} of 10 to 20 μm having {TAIL ~ a total reflection rate} of 80% or more, against a tungsten lamp 
A preferable metal foil is of aluminum or stainless steel in { HEAD ~ a thickness } of 10 to 20 μm having { TAIL ~ a total reflection rate } of 80 % or more , against a tungsten lamp
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH