18 Jul 2002
A solar powered, rechargeable light source uses white LEDs to bring light to developing communities and disaster areas
Two designers in the UK have come up with a portable light source for use in developing countries and disaster areas. The 107 x99 x25 mm sized Re-light uses solar panels and rechargeable batteries to power white LEDs, giving a safe and low-cost alternative to oil-lamps or candles.
A solar panel measuring 74 x 82 mm powers up four nickel metal hydride batteries. "It takes about 25 hours to fully recharge the batteries," says inventor Yves Sinner. "The product is designed to provide 10 hours of light from one charge and has a lifespan of up to 3 years."
The LEDs and solar panels are activated by a tilt switch. When the solar panel side of Re-light faces upwards, the LEDs are switched off and recharging begins. Turning the device over automatically switches the LEDs on and halts the recharging.
Sinner and fellow inventor Sylvain Willenz use LEDs with a light intensity of 3000 mcd. The sources have a color temperature of 8000 K.
"The tilt switch works by gravity and is positioned so that it will only turn the LEDs on when the lamp is placed into one of its working positions," Sinner told Optics.org. "These working positions are indicated by three holes that have been drilled in the casing so it can also be suspended from a wire."
Sinner and Willenz have now patented their design and are looking for investors to begin its commercialization. "Further research shows Re-light will likely find a market in outdoor activities such as camping and mountaineering," says Sinner.
Jacqueline Hewett is news reporter on Optics.org and Opto & Laser Europe magazine.