Failure modes analysis of electrofluidic display under thermal ageing

Abstract

Dielectric failure as well as optical switching failure in electrofluidic display (EFD) are still a bottleneck for sufficient device lifetime. In this study, a dielectric redundancy-designed multilayer insulator of ParyleneC/AF1600X was applied in an EFD device. The reliability performance was systematically studied by tracking the applied voltage-dependent leakage current and capacitance changes (I–V and C–V curves) with thermal ageing time. The multilayer insulator shows a more stable performance in leakage current compared to a single-layer insulator. The failure modes during operation underlying the single-layer and the multilayer dielectric appear to be different as exemplified by microscopic images. The single-layer AFX shows significant detachment. In addition, by quantitatively analysing the C–V curves with ageing time, we find that for the single AFX device, the dominant failure mode is ‘no-opening’ of the pixels. For the multilayer device, the dominant failure mode is ‘no-closing’ of the pixels. This study provides tools for distinguishing the basic failure modes of an EFD device and demonstrates a quantitative method for evaluating the reliability performance of the device under thermal ageing.

Driving Waveform Design of Electrowetting Displays Based on a Reset Signal for Suppressing Charge Trapping Effect

“…However, the charge trapping phenomenon can cause an asymmetric electrowetting effect [11], contact angle saturation, and oil backflow [12]. These problems not only directly lead to dielectric failure [13], but also make a challenge for the stable display and precise control of grayscales. The strength of the charge trapping effect is related to the polarity of the driving voltage, type, and pH value of the solution.…”

3.1: Invited Paper: Electrowetting display: Towards full‐color video reflective display

“…By constructing an organic-polymer and AF multilayer structure, the reliability of EWD can be enhanced. For example, our research showed that the double-layer structure of parylene C and AF 1600 could be used to prevent dielectric breakdown, and the stability of EWD can be improved [19] . The epoxy resin, which is the main component of photoresist has a dielectric constant ε around 3 to 4, and it has good filmforming properties.…”

Progress in Advanced Properties of Electrowetting Displays

“…Dong et al [ 18 ] fabricated a Parylene C and AF 1600 double layer structure to prevent dielectric breakdown. The advantages of a double layered dielectric material in terms of stability and reliability over a single layer dielectric material were evaluated by measuring the leaking electric charge.…”

“…The corresponding microscopy picture of the damage is given. (Images are reproduced from reference [ 18 ] with the permission of the Royal Society).…”