Electrochromic graduated filters with symmetric electrode configuration

Abstract

Graduated optical filters are commonly used for spatial image control as they are capable of darkening the overexposed parts of the image specifically. However, they lack flexibility because each filter has a fixed transmission distribution. We herein present a fully controllable graduated filter based on the electrochromic device. Its graduated transmission distribution can be spatially controlled by the application of multiple electric potentials. In this way, the control of the gradient's position and its width, transmission and angular orientation is possible. Simulation of both the spatial potential distribution and the resultant optical absorption distribution are conducted to optimize the electrode configuration and furthermore to derive a control dataset that facilitates the adjustment and thus the application of the graduated filter. Based on three objective and quantitative criteria, we identify the electrode configuration with the highest flexibility in all four controls, manufacture the device using a gravure printing process for the nanoparticle electrodes and show its successful application.