Fabrication of metal dielectric metal multilayer thin film: Color filter

A highly efficient color filters based on a multilayer thin film Ag/MgF2/Ag were deposited on a glass substrate using thermal evaporation technique. They were designed by taking into account the influence of the dispersion characteristics and the thickness of silver (Ag) metal and magnesium fluoride (MgF2) dielectric layer. The cavity thickness for the blue, green and red color filter was 273, 334, and 170 nm respectively, while the metal layer was fixed at 32 nm. The center wavelength were found to be 460, 540, 620 nm for the blue, green and red devices and the corresponding peak transmission were 73.12%, 69.18% and 63.19%, respectively and provided a satisfactory color image. The spectral response of the device was also analyzed for the oblique light incidence as the tilt angle varied up to 70 degrees and it was found to be angular dependent.