Saturday, September 7, 2013

Innovations in Light

Wireless lamps, super-efficient LED bulbs highlight new advances in lighting technology.
Fraunhofer's cordless SUPA lamps
An eyesore and a tripping hazard in one: cable clutter is a real nuisance. Now a new kind of antenna is set to banish the pest, hidden in tables and supplying electronic devices with power. The “tables” can transmit data, too.

The pretty designer lamp on the table is meant to add charm to the room. If only the annoying cord wasn’t there, then you could also put the lamp in the center of the table when it suited you. In future, you will be able to do just that thanks to SUPA Wireless technology. SUPA stands for Smart Universal Power Antenna, and the technology removes the need for electric cables, whether for lamps, laptops or smartphones. Researchers at the Fraunhofer Institute for Electronic Nano Systems ENAS have developed SUPA Wireless together with colleagues at the University of Paderborn and four medium-sized technology companies. “Without cables, you can put your lamps anywhere you like on the table – and they look better to boot,” says Dr. Christian Hedayat, department head at Fraunhofer ENAS in Paderborn.

But if there are no cables and no batteries, where does the lamp get its electricity from? The principle is similar to that of an induction cooker: fitted in the table is a network of coils, each of which represents one transmitting antenna. If electricity flows through these coils, they generate a magnetic field. This in turn induces electricity into the coil fitted in the lamp, which lights up. However, the researchers were not satisfied with the lamp being supplied with electricity only at a specific point on the table: they wanted it to work anywhere on the tabletop. But this means that a magnetic field has to be generated wherever electricity is required – in other words, on the whole table. One solution would be to install a giant coil in the table, although this would not be very practicable. The researchers opted for a different route: “We populate a printed circuit board (PCB) with numerous antennas in such a way that a magnetic field is generated only under the surface of the receiver. The distances between the antennas and the dimensions of them are carefully chosen to produce a homogeneous field,” says Hedayat.

Cordless lamps available from late 2014

The researchers have also come up with a clever solution to ensure that radiation levels are not excessive: only the antennas fitted directly beneath where the receiver is standing are switched on; all the rest stay switched off. But how does the system recognize where the lamp is standing? “There are two approaches: a physical one and a numerical one,” reveals Hedayat. The physical approach is based on the fact that the antennas perceive the receiver – that is, the lamp – as a specific load. The scientists exploit this electrical “signature”. The researchers are currently working on the numerical approach: the antenna “speaks” with the receiver, asks for its identification, and then inquires whether it is entitled to receive energy. The researchers also plan to make the question of how much energy the lamp needs part of the “conversation”. In order to further reduce radiation, the scientists have restricted it to a very short transmission range above the table. That is enough to power common electronic devices such as cellphones and tablet computers. The final development phase is currently beginning. Now it is a matter of getting the technology market-ready. According to the researchers’ targets, the first application to be launched will be the lamp including PCB in late 2014. The PCBs will be supplied in various sizes so that customers can retrofit both small and large tables.

As well as cordlessly powering lamps, however, the system is also capable of powering laptops and smartphones etc. without any cables. For such devices, the researchers have built in an additional functionality. “We don’t transmit just energy through the table, but data too,” says Hedayat. And SUPA Wireless can also be integrated in medical applications, for instance to supply implants with energy. Take pressure sensors, which are implanted in the brain of stroke patients and set off an alarm when the brain pressure gets too high. Until now, these implants are usually powered by batteries, and when the batteries were empty, surgery was needed to replace them. With the new technology, these operations become unnecessary – making life a little easier for patients.

Based on materials provided via Fraunhofer.


LED Innovation to Bring a Brighter Future 

100-240V 2W (15W equivalent) E27 Osram LED Lig...
LED Lightbulb (Photo credit: Wikipedia)
LED light bulbs can be brighter and more energy efficient than ever, thanks to a high performance LED driver newly developed by researchers from the Department of Electronic and Information Engineering.

The new driver powers LED light bulbs with an innovative approach called multi-level PWM (Pulse-Width Modulation), which delivers remarkable improvements in terms of light quality and energy efficiency, when compared to pulse width modulation and linear driver approaches currently used in LED products.

By traditional method of pulse width modulation, LEDs are fed pulsed current instead of steady DC. The drive current is turned ON and OFF at a rate faster than being perceptible by human eyes. Powering LEDs in pulses makes their light output easily controllable.

The research team, formed by Dr Lai Yuk Ming, Dr Loo Ka Hong and Prof. Michael Tse, gives the PWM method a new twist. The pulsed operation is redesigned in a way to maximize light output while minimizing wasted energy in the form of heat. The result is higher lumen per watt. Dr Loo Ka Hong said they achieved additional energy saving by up to 15%.

When used in a large scale application, it can save a lot of energy. The LED billboard on One Times Square in New York is a good example. The math goes like this: The giant display uses 12 million bulbs and 250 KW of power. If the billboard is on for 16 hours a day, the energy bill comes to US$18,000 a month. A 12% drop in energy consumption means US$2,160 in energy savings. That’s something to roll your eyes at.

Furthermore, it has lowered cooling requirements and needs smaller size heat sink compared to conventional methods. That means LED systems can be made smaller. With excellent dimming capability, the new MPWM driver allows manufacturers to create fully dimmable LEDs, which can be dimmed down to 0 watt of power. These superior qualities pave way for brighter, smarter and more versatile LED lighting solutions.

The world is switching to LEDs for huge environmental benefits. If all the traditional light bulbs in the world were replaced with energy-saving ones, lighting energy use could be cut by 40%, according to Worldwatch Institute [1]. The Energy Saving Trust has similar projections [2], which said the resultant carbon saving would be the equivalent of taking 70,000 cars off the road.

Council House Lights, Perth. Image: Wikipedia
As the greenest alternative to incandescent lamps, LEDs are a popular choice of lighting but they are not perfect. Consumers are looking for a brighter and more natural glow matching up to incandescent light bulbs. The demand for brightness is even more pronounced in high power applications such as automobile headlights and architectural lightings. LED research worldwide is looking to build a perfect substitute to incandescent. It is exciting to have advanced LED lighting with a simple solution such as MPWM that brings about significant energy saving.

Obviously, the novel technology allows a better product to be made. High illuminating performance combined with good thermal protection allowed manufacturers to create compact lighting solutions with a very high lumen output. And the additional cost is little because all of these qualities could be achieved with the use of low cost ICs. This could be music to the ear for LED manufacturers.

This innovative applied technology has already aroused the attention of the international market. Recently it has won a Gold Award at the 41st International Exhibition of Inventions of Geneva in April of 2013.

Story based on materials provided by The Hong Kong Polytechnic University, via ResearchSEA.

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