Intelligent LED to achieve better lighting and data transmission performance

伦斯勒理工学院( RPI, Troy, New York) The researchers published their in light-emitting diode ( 领导) Can greatly increase the research progress on the LED lighting performance and energy efficiency. They with samsung motor ( 三星电子的 Mechanics, suwon city) Polarization matching is developed in cooperation LED, whose lighting output increased by 20%, and characterization of the parameters of the LED conversion efficiency, electro-optic conversion efficiency increased by 25%.

new device significantly reduce the settlement of 'efficiency' phenomenon, and this phenomenon is the main limiting factor of LED device efficiency. As is known to all, when low density current through the LED, the highest efficiency. But in some applications, such as brightness higher light bulb, need to use high power devices, so the LED will lose efficiency. Although the principle of efficiency of settlement is not entirely clear, but the existing studies have shown that a large part from the electronic leakage.

'in the past two years, this issue won the wide attention from the research community; Also when the solid-state lighting technology in the application of the main obstacles, 'Fred Schubert, introduce the research project director, he is also the professor of Rensselaer, as well as the national science foundation of China ( NSF） The director of the fund intelligent light engineering research center.

'we track the electronic process of escape from the active area. In a source area, we hope that the electronic remain in the hole, so that we can restructure and light; However, if the carrier left active zone, obviously there will be no restructuring. We think that this is the origin of settling efficiency: one of the carrier left the active area; This creates a leakage in activity. '

because of the high brightness leds are working in more than peak efficiency high current density range, it is a very common phenomenon. Very natural idea is to reduce the peak efficiency working current density area, but its brightness is not acceptable, so this problem has become a big obstacle to the LED application.

other researchers have tried electronic barrier layer, but the results are not so good. The research team PRI - — Is made up of academics, industry partners and students - — Using the concept of the polarization matching. They are in the source area using four polar materials, using the four compounds of polarity and three material, use different methods to reduce the polarity, each method obtained positive results.

new LED polarity - with new design Match the active area, makes it possible for devices at high current density area peak efficiency. They studied middle LED light active area, the researchers found that the inside with polarity mismatch of materials, are likely to be electronic leak, is also the reason of low efficiency. More studies have shown that, by adopting different quantum barrier design, can greatly reduce the polarity mismatch. The traditional GaInN/GaInN to replace LED GaInN/GaN layers of the active region. Can obtain more matching polarity, reduce the efficiency of electronic leak and settlement.

LED the traditional GaInN/GaN GaInN active area and the new type of polarization matching/GaInN active area of the band diagram. （ 来源:伦斯勒理工学院)

'nitrides is a special kind of semiconductor, unlike silicon and gallium arsenide,' Schubert said. 'Gan has high internal electric field, it is a trouble. Our polarity matching structure just long in c sapphire substrate surface, so that can reduce the electric field in the active area greatly. As a result, the inhibition efficiency sedimentation phenomenon, light output power increases by about 20%, electro-optic conversion efficiency by about 25%. For the LED industry, it is a very pleasant surprise. In order to bring efficiency increased by 5%, the industry is willing to do any effort; 20% is a very great improvement. '

Schubert, points out that for the efficiency of settlement of a single reason, academia has not yet been agreed. 'The next step is to find the physical reasons behind, and thoroughly remove causes of the sedimentation efficiency, detailed understanding of all aspects. 'The team will continue to explore other possible can further improve the device LED structure. According to Schubert, leds can also implement other additional features, such as change of the color of the luminous performance, similar to sunlight and temperature, so that we can get closer to the nature of full spectrum lighting.

'we can modulation spectrum,' he said. 'So I can get a natural, adjustable light source, and can be used to process the data. This is one of our goals: produce light as well as the double function of processing data. Imagine, airport terminal lights, traffic lights on the road, in addition to the lighting function, can also be used to communication; Light source can be in the building with the room number and information, and can track objects within the building. Intelligent light source can make it. This is our long-term goal. 'Schubert, and health care, traffic system, digital display and computer networks, based on the LED and solid-state lighting lighting device can start a new wave of environmental protection, energy saving and low cost.