| abstract |
A protectively coated optical device which includes an infrared transmissive optical surface and an infrared transmissive polymer coating on the surface having low hardness, high strength and low elastic (Young's) modulus and is transmissive in the 8 to 12 micrometer wavelength range. The hardness is less than 50 kg/mm 2 , the strength is from about 10,000 to about 100,000 psi and the elastic (Young's) modulus is from about 0.2×10 6 to about 3×10 6 psi. The polymer is one of propylene, diene, polyamides, styrene, copolymers thereof and ethylene-octene copolymer, polyvinylpyrrolidene, poly(acenaphthylene), styrene/ethylenebutylene copolymer, poly(1-butene), polybrene, poly(acrylic acid, ammonium salt), polyamide resin, ethylene/propylene copolymer and ethylene/propylene/diene terpolymer, which are infrared (8 to 12 micrometers) transparent and neoprene, polyurethane, fluorelastomer, polycarbonate, polyether sulfone, polyether ether-ketone, tetcel and polyacrylate which are rain erosion resistant and combinations thereof. |