Nadine Carchon

Elastic Interconnects for Stretchable Electronic Circuits using MID (Moulded Interconnect Device) Technology

An MID (Moulded Interconnect Device) technology was developed for the production of elastic electronic interconnections. The stretchability is obtained using tortuous horseshoe shaped metallic wiring, embedded in a matrix of PDMS (poly dimethyl siloxane). In this way stretchable interconnects have been realized, consisting of 4 micron thick gold wires, embedded in 250 − 500 μm thick silicone material. . Stretchable interconnections, realised with this technology, have a maximum stretchability above 100%, with a stable resistivity of about 1.5 Ω per running cm for a track width of 100μm. A first simple operating stretchable electronic circuit has been fabricated, consisting of a blue LED driven by stretchable wiring. The technology is under development for use in biomedical applications in the first place, but has potential to be extended for various other applications like smart textiles, robotic skins, etc.

Silicon-based reflective polymer-dispersed LC display for portable low-power applications

Recently LCOS microdisplays are becoming available for personal IT applications, despite some problems which are less critical in poly silicon or amorphous silicon based displays. The most common problems which must be encountered are the polarization of the pixels and the light shielding of the silicon substrate. In this paper a methods proposed which solves the light shielding and pixel flatness problem. A non-critical back-end processing which can be applied outside the silicon foundry has been developed. The effectiveness of the light shielding on a working demonstrator display is shown. To avoid light losses caused by a polarization filter, a polymer dispersed LC has been chosen. By decreasing the cell gap we made the PDLC voltage compatible with a standard 3 micrometers CMOS process and its response fast enough to be used for video applications. It is shown that this choice is very suited in direct view and portable applications. The realized prototype has 3 bit grey levels and is video compatible and can be used in a number of applications, such as personal viewers, PDAs and data displays.

On the development of VAN LCOS microdisplays

A number of years ago it was recognized that the research on liquid crystal on silicon (LCOS) looked very promising. Right from the start it became clear that the vertically aligned liquid crystal mode yielded the best contrast, so most of the effort was reoriented towards the assembly of vertically aligned LCOS cells. In order to limit the voltage required to drive the VAN LCOS, it was decided to use inorganic alignment layers. The Microsystems lab participated in an ambitious European funded R&D project. The goal of this project was to develop a 5 million pixel - GXGA - microdisplay for high-end monitor applications. In collaboration with the Taiwan company TMDC a 0.9 inch XGA vertically aligned nematic liquid crystal on silicon (VAN LCOS) cells was developed.