Electrochromic voxel array for 3D display

We developed an electrochromic voxel array for realizing a three-dimensional (3D) display. A voxel is a unit of 3D graphic data just as a pixel of 2D data. The color of voxels is tuned not by their light emission but by their light absorption in the same way as the coloration of things in the real world. Our voxels consist of ITO electrodes on glass substrates and 1 mm cubes of an UV-curing polymer coated with electrochromic material which can change its color electrically. We utilized poly-(3,4-ethylenedioxy- thiophene):polystyrenesulfonate (PEDOT:PSS) as the electrochromic material. Our voxel array and its Al counter electrode were soaked in CaCl₂ solution. Voxels were operated with a very low voltage of about 1.0 V We demonstrated a 4x4 voxel array, and the color change of the voxels was observed not only in the top view but also in the side view.