Reflective Display using Ionic Liquid

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 0.5 s. The response speed of the devices is at least 2 Hz.