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