LED to lead the way

SMARTSHARE

Light, they say, is the darkest chapter of physics. No wonder that 128 years after Thomas Alva Edison invented the light bulb out of fear of darkness, it continues to rule the roost in terms of domestic lighting, not in India alone, but even in the developed countries.

But change being the only constant in life, never mind the dismal pace with which lighting technology has moved forward, things are beginning to change for the better. Let's understand, what lies ahead.

The incandescent bulb, emits only 5per cent of the energy it consumes as light. The rest is emitted as heat, resulting in wastage of energy. That makes the bulb a highly inefficient lighting device. Next in the line are fluorescent lights. Compact fluorescent lamps (CFL) convert between 6-15per cent of the energy into light, emerging as a viable alternative to the bulb.

That these lamps can be fitted in the same holder that holds the incandescent bulb makes them an attractive replacement bet. New investments need not be made in fixtures.

Also, the life of CFL lamp can be as high as 10,000 hours as compared to around 2,000 hours for an incandescent bulb, provided you have already not knocked it down while cleaning the dust.

The tungsten filament in the bulb is yet another weak link in the chain, which makes the bulb vulnerable. The only thing going for the bulb is the low initial price.

If the Haryana government has its way, the common bulb may soon be phased out. The state that was the first to bring electricity to all its villages way back in 1969, even if it meant fluctuating voltage and erratic supply then , is turning a new leaf . As a test case, the state has made use of CFLs a pre-condition for giving new power connections in 35 villages.

As the use of CFL spreads and the volumes improve, the cost of CF lamps could tumble, thereby increasing usage.

While things could become better with more CFL usage, the future clearly lies with LED or light emitting diodes, a technology that has been around for over four decades but is only now being commercialised for everyday use.

An LED lamp consumes far less energy for the same degree of brightness. For instance, it would consume only 6W as against 60W for an incandescent bulb and 14W for CFL for a brightness of 800 lumen. And it could last almost 40,000 hours as compared to 2,000 hrs for an incandescent bulb and 10,000 hours for CFLs.

These economic reasons apart, another advantage of LED is it is a solid state lighting system. The term solid state is a reference to light in an LED emitting from a solid object, a block of semiconductor, rather than from a vacuum or gas tube.

This makes them thermal and vibrational shock proof and, therefore, the preferred choice in cabin lighting systems in aeroplanes.

LEDs are now used in traffic signal systems, rear lights on cars, and outdoor signs. In a matter of two years, even the car headlights may be nothing but LED assemblies. By 2010, LEDs would have made their mark in homes.

Indian Railways is experimenting with LED emergency lights in passenger coaches, as they would continue to work following an accident.

As costs tumble, they could even replace regular lights in side coaches and vestibules. Municipalities in India, along with manufacturers, are experimenting with solar powered LED streetlights.

One advantage LED would have over CFLs is that they are environment-friendly and do not use environment degrading halogens and gas vapours. Since 1970, the efficiency of LEDs has improved 10-fold every 10 years.

That would enable LEDs to eventually achieve over 95 per cent efficiency, something that would make LEDs a household name. And companies in the LED lighting systems business would have a future brighter than the lamps they will make.

You would then find the common incandescent bulb only in a museum or in the columns of legendary novelist and columnist Padma Vibhushan Khushwant Singh.