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Electrochromic materials are of great interest, owing to their potential application in large area displays, active camouflage and energy saving smart windows. The effectiveness of devices fabricated for most applications depends in part on the ability to tailor the observed color in a predictable manner. Several color-tailoring strategies such as polymer blends, copolymers, and layered composites have been investigated recently. Another technique utilizing patterns of electrochromes is currently under development in our labs and affords a false way to modify a device's observed color. The pattern is composed of materials that have different observed colors; at least one of which is an electrochrome. When the pattern is viewed at a distance, the observer perceives a different color than those of the materials comprising the pattern. This `confusion' is due to diffraction. By knowing the color of the patterning materials the observed color can be predicted in a straight forward manner by color subtraction theory. The patterns are produced by screen-printing the electrochrome and other materials onto a Mylar/ITO substrate that is then used as the working electrode in a device. Following this strategy, geometrical patterns composed of thick stripes, fine stripes, small dots, and checkerboards were studied using different materials as the foreground and background colors. We will report on the fabrication of these patterned devices and their characterization by spectrocolorimetry.
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