Stretchable Yarn of Display Elements

We developed the processing technique to form three-dimensionally coiled yarns of display elements from microfabricated organic displays on flat plastic foils in order to realize stretchable electronics. Three dimensional fabrics like sweaters have been much attention as elastic substrates for stretchable electronic devices, but the deposition and patterning of functional materials on the fabric are incompatible to planar process technique of MEMS. To solve this problem, we propose the fabrication technique where firstly display components are constructed on flat plastic foils and the foils are, then, processed to form them into coiled yarns. In detail of the process, organic electrochromic displays are fabricated on the releasable parylene films above the glass. The foils with displays are cut into yarns with dicing cutters and released from the glass. To make yarns stretchable, the resultant foils are spirally rolled around elastic core fibers, forming helical coiled structure. The stretch ratio of the fabricated yarn is tuned with its pitch angle, ranging from 1 to 2. Finally, we demonstrate the projection of the selected one pixel out of 4 pixels both before and after the yarn is stretched at its ratio of 1.3.