Studies On Color Filters Of Metal-dielectric Thin Film Structure

Compared with the traditional process of making color filters with pigments or dyes,color filters based on micro-nano structure have the advantages of bright color,low pollution and long service life.It has important applications in the fields of panel display,decorative printing,sensing detection,information storage and anti-counterfeiting identification.With the development of micro-nano processing and preparation technology color filter based on nano-structure becomes an important research direction.This paper mainly involves the research of optical devices of color filter based on nano-structure,including the principle of thin film structure based on the resonance effect caused by optical Tamm state,the design of color filter structure,numerical simulation method,experimental preparation of color filter and spectral measurement.The research results mainly include:We designed metal-dielectric thin film color filters,based on the principle of optical Tamm state.The structure is composed of Bragg reflector formed by alternating two dielectric materials and intermediate metal Ag layer.We have numerically simulated the influence of the thickness of Ag film and the number of cycles of Bragg reflector on the filter characteristics of the device,by using the transmission matrix method preliminaryly.By changing the thickness of the dielectric layer,we can realize the color display controllability.With the optimized structural parameters,we have respectively calculated the structure by finite element method,finite difference time domain method and transmission matrix method.We have fabricated three kinds of color filters,including the red,green and blue filters by electron beam evaporation,and measured the transmission spectra at different incident angles.We have measured the transmission spectra at different incident angles,and analyzed the filtering characteristics,color characteristics and angle characteristics of the structure.The red,green and blue filters achieved high transmission of 76%,73% and 64%,respectively.The color filters display the same perceived color with the increased incident angle from 0° up to 40°.Compared with other sub-wavelength periodic grating structures,the metal-dielectric structure has the advantages of simple and convenient fabrication in this paper,without the process of etching complex nano patterns,and only requiring a simple coating deposition process.And it is suitable for mass production.Compared with traditional multi-layer dielectric thin film interference filter,the color filter which is based on metal-dielectric structure can be used in wide-angle applications while achieving high transmittance,and it also has a good application in the whole visible light wavelength,...