Wikipedia
Eco-Drive
Eco-Drive is a model range of watches manufactured and marketed worldwide by Citizen Watch Co., Ltd. — and powered primarily by light. As of 2007, the company estimated the drive system had eliminated disposal of 10 million batteries in North America.
Citizen introduced the Eco-Drive line to Asia, Latin America and Europe in 1995 and to the United States in April, 1996.
The Eco-Drive concept introduced several technical refinements over previous solar powered watches, including light-capturing cells that could be made virtually invisible behind the dial instead of highly conspicuous--enhancing the appearance of the watch.