Optical elements - have embossed surface of transparent composite materials, with in polymer matrix, three-dimensional structure

: Krug, H.; Nass, R.; Schmidt, H.; Spanhel, L.

Abstract
DE 4130550 A UPAB: 19931122 Elements (I) have embossed surface structure of the composite material having in a polymer matrix a 3-dimensional structure from inorganic or organic-modified inorganic components in form of nanoscale particles and/or a mol. network. Prepn. of (I) comprises the following: (a) cpd. (II) polymerisable or hardenable thermally or photochemically to a transparent polymer is mixed with sol of nanoscale particles in an organic solvent and with a polymerisation initiator, (b) mixt., opt. after adjustment of viscosity, is applied on a substrate and opt. dried, (c) coating formed is embossed with a die, with simultaneous thermal or photochemical hardening, (d) opt. prod. is post-hardened. Polymer matrix is pref. poly(meth)acrylic acid, poly(meth)acrylate, polyolefin, polystyrene, polyamide, polyimide, polyvinyl cpd., polyester, polyarylate, polycarbonate, polyether, polyether ketone, polysulphone, polyepoxide, fluoropolymer, or organopolysiloxane. Nanoscaleparticles are of oxide, chalcogenide, halide, carbide, arsenide, antimonide, nitride, phosphide, phosphate, silicate, titanate, zirconate, stannate, and/or aluminate, Mol. network is formed from hydrolysed and condensed cpds. of element of main gps. III-V, subgps. III-VI, and/or lamthanide. USE/ADVANTAGE - Optical refraction grids, interferometers, Fresnel lenses, in/out couplers for integrated optics, optical filters, couplers, branchers, multiplexers, strip waveguides, optical switches and sensors, CD discs, Bragg mirrors, and holographic elements. (I) are embossed with very low shrinkage (max. 3-5 vol.%, compared with about 15 vol.% for poly-Me methacrylate and polycarbonates and up to 500 vol.% for some inorganic/organic composite materials) with high precision and substantially to final measure