A Complex Multilayer Screen-Printed Electroluminescent Watch Display on Fabric

A screen-printed electroluminescent (EL) digital watch display on fabric is presented. This paper demonstrates the process of creating interactive printed smart fabrics suitable for a broad range of applications. In order to control the display, a series of tracks were printed that are 400 mu m wide with a pitch of 1 mm; these dimensions are lower than the previously reported literature for connections to an EL lamp. An optimized design for a bus bar layer is designed, modeled, and tested. The design improvement reduces the amount of the emitting area covered by an opaque conductor and is shown to have no negative impact on the function of the EL lamp. The design for the EL watch display includes 28 EL lamps on fabric forming four seven-segment displays. The display is the first demonstration of multiple EL seven-segment displays on fabric. The brightness is characterized and compared to commercially available blue EL lamps. The watch segments had similar brightness to commercially available lamps.