Asolar-powered watch orlight-powered watch is awatch that is powered, entirely or partially, bysolar power usingsolar cell technology.
The first solar-powered watch, the Synchronar 2100, debuted in 1972. American engineer,Roger W. Riehl became known as the pioneer of solar-powered watches for combining technologies into an impressive wearable for the time period. The Synchronar was labeled 2100 for its claim to be accurate until the year 2100 with the estimation of within one minute accuracy per year. The first solar cell watch needed sunlight and the entire top of watch was two solar panels to maximize light absorption with a digital display on side.[1] TheCitizen Watch Crystron Solar Cell (1976) was the firstquartz watch powered bysolar cell technology.[2] A model produced from 1978 by the Riehl Time Corporation was simply described as running on solar power, but having "silicon power cells" that "absorb energy from natural sunlight, daylight, or an ordinary light bulb".[3]
Some of the early solar watches of the 1970s had innovative and unique designs to accommodate the array ofphotovoltaic solar cells needed to power them (Synchronar, Nepro, Sicura and some models by Cristalonic,Alba,Rhythm Watch,Seiko and Citizen Watch). Uranus Electronics created a conventional solar cell watch later in 1975 arranging two solar cells on either side of a digital display. Their more unique model was a calculator watch that featured 12 buttons around the watch for calculations and came with solar, charger, and battery powered options.[4] In 1996, Citizen Watch started to sell analog light-powered watches under theEco-Drive name.[5] Some Eco-Drive models are popular for their translucent dials where the solar cell sits underneath the dials instead of crowding the interface.[6] Since their introduction, photovoltaic devices have greatly improved their efficiency and thereby their capacity. Watchmakers have developed their technology such that solar-powered watches had by 2009 become a major part of their range.[7] Several other watch manufacturers also use solar technology, such asOrient.[8][9][10][11][12][13]Junghans,Casio, andSeiko.[14][15]
Seiko's manufacturer,Epson introduced the Seiko Astron 7X Series in 2012 as the first GPS (Global Positioning System) solar-powered watch. GPS watches capture signals from satellites to keep a very accurate time. Epson developed a ring shaped ultra sensitive antennae capable of detecting GPS signals from 20,000 km away in the atmosphere. The ring shape follows the outer circumference of the watch around the dials.[16]
Inexpensive solar-powered watches were first sold in the 1980s and were popular amongst children, often featuring famous fictional characters such asTransformers orG.I. Joe.[citation needed]
Typically, sunlight and artificial light are absorbed by a solar panel behind the crystal. The dial is either on a layer above or actually on the solar panel. This solar panel converts the light into electrical energy to power the watch. The watch will usually store energy in a rechargeable cell to power itself during the night or when covered such as a wearer's clothing (e.g., sleeve). Citizen's watches uselithium-ion batteries to store sufficient energy to power the watch for up to five years without light exposure,[7] by allowing the watch to enter a power-saving or hibernation mode during which the seconds hand stops until the watch is re-exposed to light. Not all have a power-save mode, yet will still hold a charge for typically six months, as with uncomplicated (date only) analog versions made by Citizen.[7]
The solar-powered watches has a number of advantages:
Overall, the solar-powered watches combines the functionality of accurate timekeeping with eco-friendly technology.[20]
Disadvantages of solar-powered watches:
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