Reflectance and transmittance tuning by polarizing and chaining particle suspensions for electronic paper displays

• Main Authors: Chiu, Cheng-Pu, 邱誠樸
• Other Authors: Fan, Shih-Kang
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/18341697458308659377

博士 === 國立交通大學 === 材料科學與工程學系奈米科技碩博士班 === 100 === Electronic paper display is an emerging area of the display technology. Here we proposed an electronic paper technology by polarizing and chaining the dyed particle suspensions. The particle chains formation results in the dramatic optical change of the display medium in both transmittance and reflectance. By applying electric field at a specific frequency range, suspended particles would be polarized and induced to have specific dipole moments. The electrically-polarized particles attract each other and form particle chains in the uniform electric field. Here we investigated the phenomena of particle-chain transformation, and proposed the possible commercialized models and patents. We also showed the experimental results of particle chains formation, the feasibility of realizing an electronic paper display on a 5x5 pixel array or a flexible substrate, and an optical component of a particle suspension droplet on a microfluidic platform. In the in situ observation and the reflectance measurements, we found that the polystyrene particle suspensions would be driven when we applied a uniform electric field of 500 kHz, 0.574 MVm-1. The electric field caused the reflectance change to twice of the initial value in 625 ms (the first data point) and the contrast ratio was 2:1. The reflectance was stabled in 23.7 s and reached a contrast ratio of 10:1 in a uniform AC electric field. By implementing the color particles or the synthesis of the core-shell particles, we would be able to achieve a color electronic paper display with a short response time.