How Solar Watches Work

Energy for the Future

The Energy Crisis of the mid-1970s was one of the triggers that started CITIZEN on the quest for viable alternative energy sources. The social backdrop of the time led us to develop a “light-powered watch” that could run on the power of sunlight.

By the 1970s, battery-powered quartz watches had established the dominant market position in the Japanese watch market and became the most popular watches available. At the same time, CITIZEN noted several potential issues with quartz watches, such as a limited battery life, which would require periodic battery replacement, and the environmental impact of disposable batteries.

First Light-Powered Analog Watch

Early solar cells were too bulky and easy to break for wristwatches. However, reducing their size was thought impossible by CITIZEN’s R&D department.

In 1974, CITIZEN completed its first prototype of a light-powered analog watch with a round solar cell embedded in the dial. Two years later, in 1976, the Crystron Solar Cell, the world’s first light-powered analog watch, was launched.

How It WorksEco-Drive

The watch that never stops, wherever you are.

Inventing a technology to ensure watch that never stops anywhere in the world was one of the challenges for CITIZEN.

In 1976, we invented the world’s first light-powered analog quartz watch that runs using only light as a power source. This technology, now known as “Eco-Drive,” can generate power from any light source, artificial, natural and even dim light to keep watches running without ever replacing batteries.

As a pioneer of the field, we set new challenges for ourselves to bring forth the full potential of power generation using light.

CITIZEN’s Eco-Drive technology has won acclaim in Japan and other countries for its contribution to environmental protection. In 1996, an Eco-Drive watch was nominated as the first watch to qualify for the Eco Mark, a label managed by the Japan Environment Association (JEA). In 2014, CITIZEN became the first watchmaker to earn a Gold Prize in the JEA’s Eco Mark Awards.