Counterelectrode for an electrochromic indicating device

US4561729A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Jutta Heinz · Gerlingen, DE
• Helmut Sautter · Ditzingen, DE
• Rainer Schink · Leonberg, DE
• Lothar Weber · Stuttgart, DE

Key dates

• Filing date: Mar 25, 1983
• Grant date: Dec 31, 1985
• Expiry date: Mar 25, 2003

Classification

• Technology area (CPC G): Physics
• CPC primary: G02F1/155
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

The counterelectrode (16) of an electrochromic indicator device is made of a paste of activated carbon and an organic binder baked on a metal plate (15). The shape of the metal plate can be dished after the layer is baked on without damage. Activated carbon in the counterelectrode, operating with the usual electrolyte and a transition metal oxide electrochromic electrode, makes possible a high-charge density from migration of ions with the application of very small voltages. The electrochromic effect can be extinguished simply by a short-circuit, especially if polyvinyl alcohol is provided as a supplementary binder by dipping the baked counterelectrode therein and baking again, and even more so if the activated carbon paste contains finely divided gold from decomposition of a gold compound during baking. The counterelectrode layer can be applied by screen printing.