The Japanese manufacturer Citizen watches has been in business
since 1918, when it was founded as the Shokosha Watch Research
Institute. It may have changed its name but the company’s focus on
research and development has not dimmed in the intervening decades.

The company’s major innovation has been the
Eco-drive system. With the technology inside a citizen watch becoming
ever more advanced (and consequently power hungry) conventional battery
based power systems used in the majority of quartz watches became
impractical.

New systems developed by Casio watches such as the
highly accurate radio controlled watches required more power to operate
the receiving equipment.

The Skyhawk A-T watch manufactured by
Casio watches is an example of the system employed to synchronize with
time signals issued by the laboratories controlling atomic clocks in
Japan, North America, and Europe. They will automatically select the
correct frequency for doing so based upon location their location.

With
such drains on power it was obvious that the Eco-Drive system was
needed. The watches are equipped with titanium lithium ion battery that
is charged by an amorphous silicon solar cell located behind the dial.

This
battery type is not affected by the regular charge/discharge cycle
necessitated by the use of a solar cell. A fully charged battery will
not require charging for up to 8.7 years, however, it will enter a
hibernation mode if the watch is kept in a dark place and is used for a
number of weeks.

The company also tried to introduce a watch
based on producing power by exploiting the temperature difference
between the wearer’s arm and the surrounding environment as a power
source. These watches use a physical property known as the Seebeck
effect to generate electricity. Whilst they did receive a small scale
release in Japan and a few other countries, the watches did not prove
popular and were eventually dropped from the line.

Other
innovations from the company have been the DSP clasp. Standing for
Deployment Clasp with a Push Button, the design allows a metal style
clasp to release the watch from the arm of the wearer. This technology
has proved a boon for older users who no longer have to struggle with
buckles.