The watch that never stops, wherever you are.
Inventing technology to ensure that a watch never stops anywhere in the world
was one of the challenges for CITIZEN.
In 1976, we invented the world's first light-powered analogue quartz watch
that uses 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 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 receive a Gold Prize in the JEA's Eco Mark Awards.
Features of Eco-Drive
Watches Powered by Light
Eco-Drive is designed to convert both natural and artificial light into energy to power watches. Watches with Eco-Drive do not require any battery replacement, charging or winding to maintain constant operation.
Easy to Charge Even in Dim Light
Eco-Drive is designed so that any light source, no matter how dim, will generate the energy needed to power the watch.
Light itself is the only energy source required to tell the time with an Eco-Drive watch.
Darkness Is Not a Concern
One of the factors that distinguishes CITIZEN's Eco-Drive from other methods of keeping watches running at all times is its “power life.”
Most Eco-Drive watches continue running for more than six months on a full charge, even in total darkness.
Thanks to our power saving function, we make watches that can operate for up to even seven years without light.
Eco-Drive efficiently converts any light, including artificial, natural and even dim light, into energy. CITIZEN has focused its development efforts on two different types of solar cells.
This is the most commonly used solar cell in our watches today. It converts light into energy with high efficiency because it sits under the dial.
This ring-shaped solar cell wraps around the dial and also converts light into energy efficiently. It allows more design flexibility on the dial, as the dial surface does not need to be transparent to allow light to pass through.
CITIZEN has dedicated itself to improving its technologies to develop power efficient watch movements. Our pursuit of innovation has allowed us to bring to the market many light-powered watches with advanced functions and designs.
Insufficient Charge Warning
When an Eco-Drive watch with this feature has an insufficient charge, the second hand jumps in 2-second intervals. Once the battery is fully charged, the second hand returns to normal operation.
When an Eco-Drive watch with this feature is left in the dark, the hands stop in order to save energy. Once light hits the watch, the hands move quickly and automatically to catch up to display the current correct time.
CITIZEN invented the world's first,∗ Light-Level Indicator for analogue watches. It detects the intensity of light striking the dial and displays the electricity generation level at the moment, allowing wearers to easily gauge the charge level in any given situation.
According to research by CITIZEN WATCH CO., LTD.
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, we were facing 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 Analogue 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, we 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.
The Watch that Never Stops
When the Crystron Solar Cell was brought into the market, solar cells and secondary batteries to store the surplus energy they generated were limited in terms of generation capacity. The product life was shorter than that of battery-powered watches, which continue ticking away regardless of the time of day.
The increasing demands for secondary batteries and the growth of light-powered products among many industries during the 1980s drove CITIZEN's engineers to advance our technologies and pursue further improvements in light-powered watches.
After strenuous development efforts, we introduced the world's first industrial watch that could run up to 200 hours on a full battery charge.
The development of thinner solar cells that could utilise room lighting, as well as sunlight, and more resilient electric double-layer capacitors inspired our engineers to continue improving light-powered watches.
Then, in 1995, we added a secondary lithium-ion cell for power storage, resulting in a light-powered analogue watch that runs for six months or more on a full charge.
CITIZEN's proprietary light-powered technology, now named as “Eco-Drive”, not only to represent our exceptional technological achievements, but also reflects our concern for the natural environment. Most importantly, the name and the logo mark show our dedication to be a brand for people all over the world.
CITIZEN's brand statement—Better Starts Now—was behind the many "world's first" products. It continues today with our pursuit to develop even more exquisite light-powered watches designed with diverse functions and materials all with the goal of improving the pleasure of wearing a watch.
The world's first
The world's thinnest∗
at the time of release in 2010
The world's smallest∗
at the time of release in 2010
which takes in light
from the side of its case
The world's first
Note : There are models which are no longer in production or not available in some markets.
A Material Designed for Scratch Resistance and Comfort Wearing
CITIZEN has always striven to innovate. When it comes to the materials we use,
we take the same approach.
In 1970, we launched the world's first watch using solid titanium that is lightweight,
hypoallergenic and resistant to rust.
We processed solid titanium and then treated it with our proprietary
surface hardening technology, Duratect, to create Super TitaniumTM.
Achieving more than 5 times the hardness of stainless steel and
providing better wearing comfort,
Super TitaniumTM represents our commitment to providing people
with something better.
Features of Super TitaniumTM
Harder Materials, Fewer Scratches
Keeping your watch scratch free and undamaged doesn't mean you have to hide it away in your dresser. Super TitaniumTM provides the ideal solution to the "beauty vs. preservation" dilemma.
Thanks to CITIZEN's proprietary surface hardening technology, Duratect, watches made of Super TitaniumTM are incredibly resistant to everyday wear and tear.
Super TitaniumTM is more than
5 times harder than stainless steel
Super TitaniumTM(Duratect TIC)
Scratch comparison test by CITIZEN WATCH CO., LTD.
Light, for Better Comfort
Super TitaniumTM is approximately 40% lighter than stainless steel.
It’s so light that you almost forget you’ve got a watch on at all.
And it feels good on your wrist, whatever you’re doing.
Super TitaniumTM is approximately 40% lighter
than stainless steel
Note: Comparison of watch models with the same design,
one made of stainless steel and the other of Super TitaniumTM.
A Gentle Metal That’s Kinder on Your Skin.
Super TitaniumTM reduces the risk of adverse skin reaction to metals thanks to the use of hypoallergenic solid titanium and CITIZEN's proprietary surface hardening technology. And that’s true even for people with unusually sensitive skin.
Super TitaniumTM does not prevent all allergic reactions to metal.
More Resistant to Corrosion, for Lasting Beauty
Super TitaniumTM is more resistant to corrosion even when it comes to contact with salt water.
Wherever you are and whatever you do, you can rely on Super TitaniumTM to ensure your watch looks its best.
The pins used for the band may tarnish. CITIZEN recommends regular cleaning.
Titanium is the fourth most abundant structural metal on Earth. An incredible material that does not react to sunlight, salt water, or human body chemistry, it reduces the possibility of metal allergic reaction and is corrosion resistant.
Titanium is an active metal that reacts easily with oxygen, carbon, nitrogen, and other elements. Titanium atoms have a tendency to adhere to, and fuse with the metal molds used in pressing. To prevent the titanium sticking to the mold and to make it easier to shape, CITIZEN altered its qualities by heating it to a high temperature before pressing. This innovation considerably reduced its resistance to shaping—and opened up numerous possibilities.
Titanium is quick to react to the oxygen in the air. As a result, when titanium is drilled, metal filings tend to stick to the sides of the drill, causing friction, reducing the thickness of the drill and making it difficult to stabilise the bore diameter. CITIZEN experimented with numerous cooling oils, lubricants and machining speeds to refine traditional titanium-machining techniques and achieve stable and predictable results.
Polishing is yet another hurdle when using titanium for watchmaking. Owing to slight variations in the hardness of the crystal grains that form titanium, the conventional polishing process creates surface irregularities likely to mar the sheen of a watch. At CITIZEN we combine a number of polishing techniques, including barrel and Sallaz polishing, to achieve superior surface quality for our watches made of Super TitaniumTM.
Surface Hardening Technology: Duratect
CITIZEN's proprietary technology, Duratect, was developed to harden the surface of watch materials.
CITIZEN has various ways of surface harfening materials.
It provies a range to surface hardness (up to more than five times the surface hardness of stainless steel) while at the same time, colouring the watches in silver, black, and gold, which were once thought impossible.
The Vickers hardness test involves measuring the hardness value of the surface of a material by forcing a diamond indenter into it.
It is very widely used, including as a basis for other hardness tests.
Note that the test only measures the hardness value of the surface coating with a low load. The Vickers hardness test is not designed as a measurement to indicate scratch resistance in an everyday context.
Colour Variations of Watch Cases Made of Super TitaniumTM
Duratect Surface Hardening Technologies
This technology, which includes ionizing and coating the metal surface, makes possible diverse color variations, such as silver and pink gold.
Duratect TIC (HV1,000-1,200)
IP technology is used to harden the surface by coating it with a hard membrane for mirror and hairline finishes.
Duratect PTIC (Hv1,000-1,200)
Duratect TIC is further coated with platinum, a noble metal. Thickness can be controlled in this way without sacrificing hardness to achieve the exquisite color of platinum and color tones comparable to stainless steel.
Duratect GOLD (Hv1,300-1,500)
CITIZEN's original IP technology is used to coat titanium nitride film with gold and an alloy compound. The result is a beautiful gold hue unattainable with previous technologies.
This technology involves the plasmafication of gases containing raw materials for coating on the metal surface. Duratect DLC has a diamond-like amorphous structure for a very hard and smooth coating that gives a distinctively luxurious dark gray hue to treated surfaces.
Duratect DLC (Hv1,000-1,400)
DLC (Diamond Like Carbon) is a coating technology using a hard amorphous carbon film made up mainly of carbon and hydrogen. The result is a bold dark gray color.
Argon ions are bombarded onto the target metal with this technology. The atoms deposited are then used to coat metallic surfaces. In addition to achieving about twice the surface hardening of conventional technologies, this technique results in excellent hypoallergenic properties.
Duratect α (Hv2,000-2,500)
This is CITIZEN's ultimate new surface hardening technology, offering twice the hardness of Duratect TIC/PTIC. Coating materials that contain no noble metals results in high scratch resistance and gentleness on the wearer’s skin.
Nitrogen and oxygen injected into a vacuum furnace are processed using heat to form a hard layer 20 μm to 30 μm thick.This technology can be used to produce surfaces resistant to scratching even under harsh usage conditions.
Duratect MRK (Hv1,300-1,500)
The titanium surface is hardened by coating it with a material infiltrated by nitrogen and oxygen for a mirror finish that is highly resistant to scratches.
This technology represents a combination of gas curing technology with low-temperature plasma or sputtering technology. Overlapping the hardened layer with a hard coating further improves overall material hardness and hypoallergenic properties.
Duratect MRK/DLC (Hv1,000-1,400)
Duratect DLC hard amorphous carbon film is applied to Duratect MRK surfaces made with gas curing.
Duratect MRK/α (Hv2,200-2,500)
Titanium materials with Duratect MRK surfaces are coated with Duratect α, the ultimate surface hardening technology in CITIZEN's Duratect lineup.
Exploring Ideal Materials for Watches
The origins of Super TitaniumTM stretch back to the 1960s, when the Apollo moon mission first revealed titanium’s potential as an industrial material. Inspired by this glimpse of the future, CITIZEN engineers set about exploring how they could apply titanium to watch manufacturing
The First Titanium Watch
In 1970, we produced the X-8 Chronometer, the world’s first watch with a solid titanium case. The name expressed our high hopes for titanium and its infinite possibilities as a material.
Titanium Watches for Everyone
CITIZEN was impressed with titanium's hypoallergenic properties. In fact, we made it our mission to create innovative watches that were safe and gentle on the skin, so that everyone could enjoy wearing a watch.
The Attesa, introduced in 1987, was an all-titanium hypoallergenic watch created in-house.
Super TitaniumTM, a CITIZEN original
CITIZEN wanted to explore titanium’s infinite possibilities as a material for watchmaking. It was never going to be easy. But we met the challenge by creating our own titanium-processing technology, and following that up with our proprietary surface hardening technology, Duratect. The challenge goes on in line with the spirit of "Better Starts Now", as we look forward to making future breakthroughs.
Improvements in our titanium-processing technology have enabled our designers to create a wide range of great designs. Thanks to advances in our surface-hardening technology, we have also succeeded in creating models with higher resistance to scratches in a wide range of colours and with stronger hypoallergenic properties.
We are on a never-ending journey to provide everyone, everywhere, with the chance to wear a beautifully designed and comfortable watch. This was the dream that first led the team at CITIZEN to develop Super TitaniumTM—and it still drives us today, as we address the challenges that come up en route to creating ever better timepieces.
Titanium diver watch
with the world's
to the depth of
∗At the time of release in 1982
allergy resistant watch
Note : There are models which are no longer in production or not available in some markets.
Satellite Wave & Radio-Controlled