Archive : 25 March 2015 год
While organic LEDs can be incorporated in thin layers and used on curved surfaces, large area displays are not cost effective because of their low efficiency and short operating life.
One alternative to OLEDs is electroluminescence, in which phosphors are excited in an electric field and researchers at the INM–Leibniz Institute for New Materials have developed a method that enables electroluminescence to be deployed cost effectively on large, curved surfaces. The team says the light emitting layer and all other components can be produced using wet chemical printable methods.
"We only need temperatures of less than 200°C," said Peter William de Oliveira, head of the optical materials program division. "This means we can apply all the required partial layers, even to films or other flexible substrates."
The luminous unit consists of two electrically conductive layers, with the light emitting particles sandwiched in a dielectric binder layer. At least one of the conductive layers is also transparent. On application of an AC voltage, light is emitted from the electroluminescent layer.
"We embed functionalised zinc sulphide nanoparticles as phosphors into the binder layer," de Oliveira explained. "These are doped with copper or manganese. This allows the generation of green and blue-green light."
The electroluminescent light sheets can be connected directly to the 230V mains supply, with no need for rectifiers, ballast capacitors or other switching units.
The researchers are now working on different phosphors. "Our goal is to generate white light by means of an altered doping or by introducing coloured pigments into the luminous layer," said de Oliveira. The team also wants to alter the materials so the displays can operate from a lower voltage.
Looking to boost its presence in 5G communications, National Instruments is acquiring BEEcube, a leading supplier of FPGA based prototyping and deployment products for advanced wireless research, wireless infrastructure and military/defence applications.
"As the Internet of Things drives greater demand for data and an increasing number of connected devices, NI is excited to be at the forefront of research and prototyping tools for next generation 5G wireless technology," said Charles Schroeder, director of RF communications. "NI and BEEcube share a common philosophy and vision of platform-based design and we believe the combination of the two companies will strengthen our leadership position as 5G progresses toward commercialisation."
Chen Chang, BEEcube's founder and CEO, added: "For many years, BEEcube has been at the forefront of technology innovation in telecommunications applications. By joining NI, we will have the resources to continue to drive 5G research and provide our customers solutions which enable infrastructure deployment on a global scale."
BEEcube will operate as an NI subsidiary and will continue to market its products under the BEEcube brand.