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Electrochromic Material for Information Recording

IP.com Disclosure Number: IPCOM000081077D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Chang, IF: AUTHOR [+2]

Abstract

Tungsten trioxide (WO(3)) films up to several microns, formed by direct evaporation of the compound, have been shown to exhibit electrochromic behavior.

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Electrochromic Material for Information Recording

Tungsten trioxide (WO(3)) films up to several microns, formed by direct evaporation of the compound, have been shown to exhibit electrochromic behavior.

As shown in Fig. 1, WO(3) films, one to two microns thick, have been directly evaporated onto conventional paper. The double electrode stylus shown is then used to write on the coated paper. Current passing through the paper between the spaced electrodes causes a deep blue trace to be made on the originally white background. Typically, a field of 10/4/V/cm and a charge of 100 millicoulombs/cm/2/ have been found adequate. As might be expected, when the WO(3) coated paper is moistened, the writing speed is significantly enhanced.

An alternate arrangement is shown in Fig. 2. Here, a single electrode stylus is employed in place of the double electrode stylus used in Fig. 1, and the WO(3) coated paper is mounted upon a conducting base electrode, as shown. Where the single electrode stylus is W and a voltage of from 10 to 20 volts is applied between the electrodes, the stylus may be manually moved at normal handwriting speeds to write information. More effective results are achieved when the paper is somewhat moistened. Likewise, as the voltage is increased to provide higher currents, higher handwriting speeds may be achieved. Moreover, where the stylus is aluminum rather than tungsten (W), even higher handwriting speeds may be achieved. The WO may be deposited upon the...