Citizen is celebrating the 50th anniversary of its first analog light-powered watch with the release of its Eco-Drive Photon watch in a limited edition, with two variants of 5,000 units each that pay homage to the peculiar physics of light.
In the 1970s, the world of the watch was undergoing a revolution that even those who instigated it could scarcely understand. In the late 1960s, the Swiss Centre Électronique Horloger consortium developed the Beta 21 quartz movement, which went into production in 1970, though Japan’s Seiko beat them to market with its Quartz Astron 35SQ in December 1969. These were followed by the US Hamilton Watch Company, which in May 1970 revealed its Pulsar P1 digital watch.
Along with a number of other pioneers, they caused a sensation. They displayed an accuracy that before could only be found in nautical chronometers, and watches like the Pulsar did away with hands in favor of LED digital displays. By 1973, even James Bond was wearing one.
Photon
However, these early quartz marvels had a couple of drawbacks. Until the economies of scale kicked in that would shove mechanical movements into near oblivion within a decade, quartz watches were priced well at the luxury end of the market. The other was that the silver oxide batteries that ran them had the longevity of a peanut at an elephant convention – especially if the watch had an electromechanical analog display with its power-hungry step motor.
That sort of battery consumption can be a real dealbreaker. It’s the reason why I gave up on quartz watches a few years ago and now wear a mechanical job with an automatic movement. Before this, I wore a nearly identical watch except it had a quartz movement that ate batteries at a rate of one every 12 to 18 months. That’s a real pain when you have a dive watch that requires a certified watchmaker to replace the batteries and such technicians aren’t easy to find in my neck of the woods.
In 1974, Citizen produced its first prototype of a light-powered analog quartz watch that incorporated a solar cell on the watch face. A production version called the Crysotron Solar Cell hit the market in 1976 with a grid of eight solar cells on the dial.
Citizen
These helped to top up the battery as well as taking some of the work of powering the movement off it, but the watch had to spend a lot of time in the light because of efficiency issues. In the 1980s the company focused on making solar cells and rechargeable batteries more efficient. As a result, by 1986 Citizen’s watches could run for 200 hrs on a single charge.
In 1995, Citizen officially called their proprietary tech the Eco-Drive and released its Eco-Drive Calibre 7878 that had the solar cell mounted underneath the dial using a non-transparent surface that allows non-visible light to filter through. Around the same time, lithium-ion batteries came along, extending the power reserve to 180 days in total darkness. For context, lithium-ion batteries also drove nuclear pacemakers out of the market for the same reason.
Today, the Eco-Drive line includes professional dive watches, are capable of receiving GPS signals for exact timekeeping, and some models are as thin as 2.98 mm. Meanwhile, the Eco-Drive 365 had boosted the power reserve to 365 days per charge.
Citizen
Released on March 19, 2026, the Eco-Drive Photon pays tribute to this technological innovation by also paying a bit of homage to the physics of light and its paradoxical nature. The dial consists of two metal plates that boast ripple-like slits layered over a structural color film. The result is a three-dimensional effect with the interplay of light in the slits creating shifting hues.
The idea behind this is to invoke the double-slit experiment, which demonstrates how light behaves as both a particle and a wave, depending on how it is observed. The experiment involves a metal plate with two slits, through which light passes from a coherent source such as a laser. When the light passes through the slits and hits a sensor or photographic plate, it can behave either like a wave or like a stream of particles. It may form an interference pattern, as if two sets of waves are overlapping, or produce two distinct bands, as particles would, depending on how the measurement is made.
Anyway, that’s all for science class.
As to the Photon, it runs on a Calibre E036 (Eco-Drive) with a 365-day power reserve and has an accuracy of ±15 seconds per month. This is sealed in a case of proprietary Super Titanium with a sapphire crystal. The case has a diameter of 41 mm, is rated to a depth of 330 ft (100 m), and is secured with a Super Titanium band. The whole thing weighs in at 85 g (3 oz).
Set to be released for sale later this year, the Photon comes in two versions of 5,000 units each, one finished in Duratect titanium carbide, and the other in Duratect amber yellow. They retail for between US$1,000 to $1,200.
Source: Citizen
