世界真奇妙:開燈就有無線寬帶

英國愛丁堡大學的一位教授研究出了一項新技術，能夠讓普通的電燈泡作爲無線網絡信號傳輸器，只要開燈，就能無線上網。據介紹，這項發明被命名爲D-light，只要將房間裏傳統白熾燈換成LED燈，便可讓燈泡變成無線網絡發射器。它通過改變房間照明光線的頻率進行數據傳輸，每秒傳送速度超過10兆，與典型的寬帶連接不相上下。它可以應用於醫院、機場、軍隊甚至於水下。從理論上說，飛機乘客甚至能夠利用機艙內發出的光照信號上網衝浪。除此之外，這項技術還可用於從空白電視信號頻段或者未被使用的衛星信號發送無線數據。

Light bulbs could be soon used to broadcast wireless Internet, a leading physicist has claimed.

Harald Hass said he has developed a technology which can broadcast data through the same connection as a normal lamp.

By simply turning on the light in the room you could also switch on your Internet connection, he said in a speech.

Other possibilities of the device - which he has dubbed ‘Li-fi’, or Light Fidelity - include sending wireless data from the ‘white space’ in your television spectrum or unused satellite signals.

Professor Hass, of the school of engineering at Edinburgh University in the UK, said that currently we use radio waves to transmit data which are inefficient.

With mobile phones there are 1.4 million base stations boosting the signal but most of the energy is used to cool it, making it only five per cent efficient.

By comparison there are 40 billion light bulbs in use across the world which are far more efficient.

By replacing old fashioned incandescent models with LED bulbs he claimed he could turn them all into Internet transmitters.

The invention, dubbed D-Light, can send data faster than 10 megabits per second, which is the speed of a typical broadband connection, by altering the frequency of the ambient light in the room.

It has new applications in hospitals, airplanes, military, and even underwater. Aeroplane passengers could in theory be able to surf the Internet from signals beamed out of the lights on board.

‘The way we transmit wireless data is inefficient electromagnetic waves, in particular radio waves which are limited, they are sparse, they are expensive and only have a certain range,’ Professor Hass said.

‘It is this limitation which does not cope with wireless we are running out of efficiency.

‘Light is part of the electromagnetic dn't it be great to use it for wireless communications?’

He added that the visible light spectrum had 10,000 more times the space than radio waves, making it the ideal range to use.

During a lecture professor Hass showed off a desk lamp which had been fitted with an LED light bulb which transmitted data to a receiver on the table below it.

Whenever he put his hand in the beam of light the video, which was beamed onto a screen behind him, stopped playing as the signal was being blocked.

Professor Hass said the technology has not yet been integrated with smart phone but he hopes that soon it will be.

‘Everywhere that there is light, these are potential sources for data transmission,’ he said.

‘For me the applications of it are beyond we need to do is to fit a small microchip to every potential illumination device and this would combine illumination and data transmission, and this could solve the problems facing us in wireless communication.’

Vocabulary:

White Space: 空白電視信號頻段，指各電視頻道之間的無線傳輸節目的頻段。