Invent a better light bulb

Ask who invented the light bulb, and most people will say “Edison”

He didn’t of course, but I always think the story of the multiple inventors of the light bulb sheds some interesting light on the distributed way that innovation really happens: The person that gets the credit is very seldom the sole contributor, and it all takes a lot longer than people think.

The first electric light was invented by the English chemist, Sir Humphrey Davy, who demonstrated at the Royal Institution in 1802 that electricity passing through a platinum strip will produce light.  The platinum was incredibly expensive and it burnt out far too quickly to be commercially useful, but it was a start. After a succession of other inventors over the next 70 years, another Englishman, Joseph Swan patented an evacuated carbon filament bulb in 1878. The filament was made of carbonised paper, and didn’t last that long, but it worked.

Simultaneously in Menlo Park in Newark, New Jersey, Edison was struggling to develop his own commercially viable light bulb. He’d realised that if the bulb was to be both durable and bright he needed to find a very thin, strong source of carbon for the filament.    He tried thousands of materials; from paper to coconut palm, from his employees’ beards to spiders web, but everything burnt out within a few days.  One day, in 1880, he absent mindedly pulled a fibre off a bamboo fan they used for evaporating liquids in his lab.  Noticing that it seemed to have a different structure to the bamboo they’d tried before, he asked his assistant to try it…. and it worked: a rather dim but useable 8 candlepower lamp lasted for an amazing 2450 hours. Edison then sent people all over the world looking for the source of the bamboo.  One unfortunate adventurer, John Segredor, died of yellow fever in the process (Edison paid for his burial), but finally they found some growing in Kyoto, Japan.  In 1881 Edison imported 50,000 fibres and set up his electric light company and started manufacturing.

So why do we always think of Edison as the inventor of the light bulb?  I think the main reason is that he developed both the improvements to the light bulb that made it commercially viable, and the electricity system to power it. After all, people want light, not light bulbs. It also helped that he patented aggressively, was a brilliant spin doctor and was famously litigious in trying to squash his competitors.

I think electric light has genuinely been one of the technological inventions that has most benefited human lives.  However, the incandescent light bulb was also incredibly inefficient: 95% of the energy was wasted as heat and they burnt out every year or so.  But everyone had got used to this, so they’d become a low cost commodity item and innovation had ground to a halt.

However,  in the last decade we’ve started to see the results of a new wave of innovation, stimulated both by the need to improve energy efficiency, and by the big manufacturers wanting to improve their competitive position.

This has been very successful, so after a little diversion into compact florescent bulbs, LED bulbs are now coming into their own. They now give a nice light and the cost has been declining rapidly so a modern LED bulb costs a few pounds, is at least 5 times more efficient than an incandescent bulb and can last 25 times longer.  Lighting is a major power user, so the change has already reduced the UK’s electricity peak electricity demand by 7% in just 5 years, which is good news for keeping the lights on, given the fears about future shortage of generating capacity.

As with the incandescent bulb, inventing the LED bulb took a while. The red LED was invented by Nick Holonyak in the early 1960s at General Electric but it wasn’t until the invention of the blue LED in 1994 by the Nobel prizing winning Shuji Nakamura that it became possible to think seriously about creating a white light.  It then took about a decade of expensive further development, before in 2010, Philips succeed in producing the first bulb that could genuinely be seen as better than a 60W incandescent bulb.  But it cost $40.  However as the manufacturing volume increased, the cost plummeted, helped by legislation in dozens of countries around the world banning inefficient incandescent bulbs.

It’s possible that the LED bulb will remain just a better source of light, but I suspect that now electronics are part of the light bulb package, much more interesting developments are in the pipeline.  Not only could a ‘smart light bulb’ change in colour to suit the time of day or the application, it could communicate with your phone or other devices by “Li-fi” ie  pulsing the light at a few GHz.  Some see this as a potentially useful, secure, local alternative to congested Wi-fi  networks.  Philips are trialing a lighting system for supermarkets that sends you special offers as you pass by.  More importantly, Li-fi might be used to allow vehicles  to send and receive data about their environment: for example, traffic signals might give information about congestion ahead, or brake lights could pass information to the car behind about the rate of braking.

Edison is probably turning in his grave about the abandonment of his incandescent bulbs, but I think the future is bright.