新技术：开灯就有无线宽带

英国爱丁堡大学的一位教授研究出了一项新技术，能够让普通的电灯泡作为无线网络信号传输器，只要开灯，就能无线上网。据介绍，这项发明被命名为D-light，只要将房间里传统白炽灯换成LED灯，便可让灯泡变成无线网络发射器。它通过改变房间照明光线的频率进行数据传输，每秒传送速度超过10兆，与典型的宽带连接不相上下。它可以应用于医院、机场、军队甚至于水下。从理论上说，飞机乘客甚至能够利用机舱内发出的光照信号上网冲浪。除此之外，这项技术还可用于从空白电视信号频段或者未被使用的卫星信号发送无线数据。

新技术：开灯就有无线宽带

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 data...and we are running out of efficiency.

‘Light is part of the electromagnetic spectrum...wouldn’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 imagination...all 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.’