Metallized viscoelastic control layers for light-valve projection displays

Abstract

In the first part of the three-paper series on light-valve projection with metallized viscoelastic control layers, the technologies for producing suitable layer systems as well as the observed performance of such light modulators are described. Optimum conditions for elastomer preparation and gel-layer formation by means of spin coating are given. Before metallization in a multistep vacuum evaporation process, the elastomer layers were coated with a thin pellicle whose mechanical properties and thermal expansion lie between those of the silicone gel and the silver mirror. For pellicle formation, a novel ‘soft’ plasma process was developed. The deformation behaviour of the completed control-layer systems was tested by means of an interferometry set-up and found to be sufficient for light-valve applications. Furthermore, the long-term and elevated-temperature performance of the metallized viscoelastic layers was investigated. Continuous operation over more than 1 year did not yield any appreciable deterioration, while the maximum deformation amplitude increased very remarkably if the operating temperature was elevated by a few tens of degrees Celsius. Finally, possible improvements of the present control-layer technology are proposed.