Reflectivity Improvement by Particle Neutralization in a Charged Particle-Type Electronic Display

Eight sample panels using an indium tin oxide(ITO)-coated glass substrate were fabricated, with barrier ribs formedof 55 height and 10 width. The upper and lower substrates were designed with the same panel condition, so acell gap of 110 was obtained. The charged particles in a cell consisted of TiO2 (for white color) or carbon black (blackcolor), negative or positive charge control agents, and a polymer. The average diameter of the two types of particleswas commonly 10 , and their q/m value was -4.5 μC/g and +4.5 μC/g, respectively. The electrically opposite particlesmixed by an agitator were loaded into their cells by a simple particle-loading method. The discharging processproceeded at a humidity of 80% and a temperature of 30℃. Reflectivity was measured depending on discharging time,and a hysteresis curve by bias voltage obtained for comparison between the neutralized and non-neutralized panel, inwhich the superior optical property of the neutralized panel was ascertained.