Design of plasmonic color filters to realize full-color reflective displays

Abstract

With the huge growth of display market, reflective color filters are one of on-demand component of market nowadays. Because conventional color pixels are horizontally aligned, it is impossible to get high reflectance for primary colors. Here we suggest and develop a new type of reflective color filter using vertically aligned active layers. Firstly we investigated the possibility of designing vertical color cell. The total number of possible cell combination and its color expression mechanism is obtained. After that, using plasmonic metasurfaces, the resonance tuning ability of MEMS and microfluidic channel was investigated and optimized by simulation. Each method can shift the plasmon resonance wavelength at least 80nm, which can cover whole visible range by 3-level active tuning. Finally, we demonstrated the index tuning method which can be combined with microfluidic channel. The prototype sample is fabricated by evaporation and e-beam lithography. The observed color changes significantly by dropping liquids on it. By reflection spectrum measurement of small spot, the dip reflectance about 30% was obtained and resonance dip at 436, 528, 608nm. Therefore, the full color expression can be accomplishable by designed structure.