Optical Materials

One of the major topics of the department „Optical Materials“ is the material glass and the improvement of its characteristics as well as increasing its functionality by glassy, organic-inorganic and ceramic coatings. Systems developed so far include

  • coatings for the increase of the bending strength of glass
  • coatings for the conservation of the bending strength of glass
  • transparent coloured coatings based on noble metal nanoparticles in glassy (silicate glass) or ceramic (TiO2, ZrO2) coatings
  • antireflection, near infrared reflection and colour filter coatings built up as multilayer interference stacks, where up to five single layers can be coated before densification in a single firing run
  • antiglare coatings on the basis of glassy coatings containing microparticles
  • thin (a few µm) translucent as well as nontransmissive white coatings free of heavy metals and fluorides, based on pigments in a silica matrix
  • photochromic coatings on the basis of organic photochromic dyes in an organic-inorganic nanocomposite matrix

A second field of work are new optical materials on the basis of nanocomposites. These exploit the fact that light scattering can be neglected in composite materials if the size of the nanoparticles is below 10-15 nm. Thus, new solid state physical characteristics can be “imported” in materials via nanoparticles, without sacrificing their transparency. This requires an exact control of the surface properties of the nanoparticles. Examples are:

  • transparent fillers for optical adhesives and electronic moulding resins with low dilatation, low shrinking, increased elastic modulus or customised refractive index
  • new holographic materials for the production of optical microstructures by laser imaging
  • embossed optical microstructures on glass, polymer and metal substrates for light control or product identification
  • photocatalytically active coatings on substrates of all sorts, particularly on sensitive substrates like polymers or textiles

A third topic is the development of glassy coatings on metals (noble metal, aluminium, brass, copper etc) as

  • highly scratch- and abrasion-resistant protective coatings
  • high temperature tarnish protection coatings
  • corrosion protection coatings for high temperatures
  • easy-to-clean anti-fingerprint coatings
  • anti-adhesive coatings for technical applications requiring high working temperatures

In addition to materials development, all three working areas depend on the development of economic coating technologies leading to high quality results. We are experienced in:

  • spin-coating for small-sized substrates
  • dip coating for small- and medium-sized substrates (up to 1 sqm)
  • spray coating
  • flexo printing
  • screen-printing
  • continuous coating of plastic films, textiles and paper by roll or doctor blade methods in a pilot coating line up to a width of 60 cm