Features 02
The technology driving world-leading accuracy*
Achieving greater accuracy has been a key mission for CITIZEN ever since we first began making watches a century ago. After creating a purer, more refined individual second by rethinking the crystal oscillator, the next challenge we had to confront was how to keep marking those seconds precisely, reliably and beautifully, using light as the sole power source. You cannot make a watch accurate to ±1 second per year unless you are fanatical about the precision of every element that goes into it. CITIZEN succeeded in making this watch because we are a manufacture and developed all the components from scratch ourselves.
As of May 2021, for an analogue light-powered autonomous watch, according to research by Citizen Watch Co., Ltd.
LIGA TECHNOLOGY
The quest for more precise components
The use of precision-manufactured components is a prerequisite for telling the precise time. To achieve precision manufacturing, we adopted the LIGA fabrication process for components like gears and springs that are normally made by pressing and machining. Adopting this process eliminated even the smallest eccentricity from the gears, resulting in components of quite unprecedented precision.
BACKLASH SUPPRESSION MECHANISM
No play for the gears—
or the second hand
When a watch experiences gear backlash, the second hand visibly twitches. For normal quartz watches, this phenomenon is within tolerance, but it is something that we, in our quest for the purest, most refined individual second, were not prepared to accept. We developed and installed a special gear, made with the LIGA process, that pushes against the direction of rotation of the gears to prevent backlash. As a result, the second hand keeps telling the precise time, lining up perfectly with the minute tracks, second by second. Thanks to our first-of-a-kind system that is able to rotate the second hand both forwards and backwards, the watch can quickly display the correct time when it wakes up from power saving mode.
TEMPERATURE CORRECTION FUNCTION
Monitoring the temperature
once per minute
The integrated circuit, the “brain” of the watch, includes many CITIZEN proprietary technologies. One of these is a temperature correction function that monitors the temperature in the watch movement once per minute and adjusts its frequency accordingly. There are tiny individual differences between crystal oscillators. Which is why CITIZEN tests the thermal characteristics of every crystal oscillator it uses. Not only did we double the number of points we temperature test in the manufacturing process, we also improved the testing methodology for a tenfold jump in measurement precision.
THREE PROTECTIVE FUNCTIONS
Telling the precise time
whatever happens
Systems that correct, monitor and protect the second hand from external shocks like bumps and magnetism have an important role to play when it comes to marking the individual seconds with perfect purity. The watch includes a shock counteraction function (which locks the rotor to keep the hands in place and then release them instantly); an automatic hand correction function (which regularly checks the position of the hands and automatically resets them in the event of deviation); and an antimagnetic function which can resist magnetic fields of 4,800A/m.
MOTOR
A second hand that moves
with force and beauty
We wanted this watch to express each individual second beautifully. To do this, for the first time on an Eco-Drive watch, we used a brass second hand matched with a specially developed powerful high-holding-torque motor. Despite the brass second hand having roughly twice the unbalanced weight and moment of inertia of an aluminium hand, it rotates with confident elegance, coming to a precise stop every second.
Eco-Drive
Everything…
powered by nothing but light
Our mission is to tell the time with accuracy of ±1 second per year on a continuous basis. We achieved this by using light-powered Eco-Drive, a core CITIZEN technology with over 40 years of history. We aggressively reduced electricity consumption so that we could power the whole movement—the power-hungry AT cut crystal oscillator, the temperature correction function and the heavy brass second hand—with nothing but light. A single full charge will keep the watch running for over six months. We created a watch that keeps telling the precise time, and all you need is…light.
