Maximum Deformation Amplitude Research Articles

Deformable segmented mems mirror

A MEMS device having a deformable segmented mirror. The mirror includes a plurality of movable segments supported on a substrate using spring vertices, each vertex having a fixed plate and one or more springs. In a representative embodiment, three springs support each movable segment, where each spring connects the movable segment to a different spring vertex. The MEMS device also has a plurality of electrodes, each of which can be individually biased. A movable segment moves in response to a voltage applied to an electrode located beneath that segment while the deformed springs attached to the segment provide a restoring force. Due to the fixed plates, motion of each movable segment is substantially decoupled from that of the adjacent segments, which makes the shape of the segmented mirror relatively easy to control. In addition, segments in a deformable mirror of the invention can be displaced by a distance that is significantly larger than the maximum deformation amplitude for a membrane mirror of the prior art. The MEMS device can be fabricated using two silicon-on-insulator (SOI) wafers and an etch fabrication technique.

Metallized viscoelastic control layers for light-valve projection displays

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.

Possibility of investigating the characteristics of controlled gelatinous dynamic light-modulating media by laser interferometry

A report is given of the application of laser interferometry to a study of dynamic deformations of a gelatinous medium. It is shown that the shape of vibrations of the gel can be determined and the amplitude of the acoustic field can be found with a resolution of ∼3 μ in steps of 10−3 λ /2. The dependence of the vibration amplitude on the applied voltage is determined for part of the surface with the maximum deformation amplitude.