Powered by Light
What is the ideal source of power for a watch? CITIZEN created the world’s first light-powered analogue quartz watch in 1976. We named the technology Eco-Drive in acknowledgement of its eco-friendly origins. It converts any kind of light into energy to power a watch and stores the surplus on a power cell. On a full charge, an Eco-Drive watch runs for months even in darkness with no need for regular battery replacement. As a light-power pioneer, we continue exploring new possibilities.
No need for regular battery replacement
Once upon a time, everyone accepted that quartz watches had to have their batteries replaced at regular intervals. But the advent of Eco-Drive overturned the conventional thinking. Eco-Drive is a light-powered technology that drives watches by capturing light and converting it into energy using an inbuilt solar cell. Suddenly the hassle of replacing batteries was a thing of the past.
Runs even in dim light
Eco-Drive is designed to charge from ordinary everyday light sources like indoor fluorescent lighting and desk lights. You can go about your everyday life confident that your watch will never stop.
* To get the most out of your watch, set aside about five or six hours per month to charge it in sunlight.
Runs for over six months even in darkness
Do you need light to generate power for your watch all the time? Not with Eco-Drive. A single full charge is enough to keep Eco-Drive working for over six months in total darkness. Indeed, some models equipped with power save function can run for as long as seven years.
* Some models run for less than six months.
Solar cells absorb light and convert it into energy. With Eco-Drive, we use different solar cells for different models to increase the range of designs we can offer.
As the name suggests, this is the most commonly used solar cell in our watches. It sits directly beneath the dial. Due to its excellent power-generation capabilities, it is used in many of our advanced-function models.
This ring-shaped solar cell sits above the dial, encircling it. With a ring solar cell, there is no need for the dial to be translucent, allowing for greater latitude in dial design.
Reducing energy consumption
How can we get the most out of the energy we generate from light? CITIZEN’s relentless focus on reducing energy consumption has driven the creation of advanced functions and other value-added innovations. We redesigned the circuits and programming of the integrated circuit (IC) and optimised the motor with numerous subtle tweaks to achieve better energy performance.
Insufficient charge warning
This function warns you when the watch is inadequately charged by making the second hand move at two-second, rather than one-second, intervals.
Power save function
This function, which temporarily stops the hands to save power when the solar cell is not exposed to light for a certain period, is what makes Eco-Drive’s long running time possible. When light is detected, the hands resume moving as normal to indicate the time.
CITIZEN was the first company in the world to build a Light-Level Indicator into its analogue quartz watches. The indicator detects the intensity of light striking the dial and displays the current level of electricity generation, allowing the wearer to gauge the amount of power being generated at any given moment.