We propose a reflective display device using an array of encapsulated micro droplets of a room temperature ionic liquid mixed with pH indicator dyes. The array is embedded in and addressed by a passive matrix. Parylene- on-liquid deposition is employed to encapsulate the liquid droplet arrays. When applying current to each droplet, the liquid mixture changes its color, providing the ability to display a pixel of graphics information. Once changed, the droplets can be tuned back to their initial color by reversing the direction of the applied electric current. The on-off switching time is less than 0.5s. The response speed of the devices is at least 2Hz.

References :
Nguyen Binh-Khiem, Kiyoshi Matsumoto, Isao Shimoyama, “Reflective display using ionic liquid,” 22nd IEEE International Conference on Micro Electro Mechanical Systems (MEMS '09), pp. 168-171, Sorrento, Italy, 2009. [Proceedings]