U.S. Philips Corporation

Ralph M Hanzen

Paul Van Der Sluis

Freddy Roozeboom

Peter Alexander Duine

Reiner Maria Jungblut

Friedrich J Den Broeder

Cornelis Draijer

A description is given of an optical switching device (1) comprising a transparent substrate (3), a switching film (5) of a hydride compound of a trivalent transition or rare earth metal having a thickness of 300 nm, and a palladium capping layer (7) having a thickness of 30 nm. The capping layer is in contact with hydrogen. An electric current through the switching film (5) can be switched on and off between the terminals (9, 11). Joule heating of the switching film (5) causes a rapid transition from the transparent trihydride state to the absorbing dihydride state. By switching off the current, the switching film (5) cools down, which results in the formation of the absorbing dihydride state. The conversion between both states is reversible and can be repeated many times. The device can be used for controlling light beams, or it can be used in or for a display. Optionally, cooling of the switching film (5) is obtained with a Peltier element in thermal contact with the switching film (5).

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Eindhoven, Netherlands

Ralph M Hanzen