Light-emitting diodes are unbeatable in terms of energy efficiency. A one-watt LED delivers roughly the same optical output as a hundred-watt light bulb. If a high light output is required, however, the tiny light sources are not the preferred means of illumination. A novel optical component is set to change that situation.
It directs the light to the exact spot where it is needed. In the case of a desk lamp, for instance, the light can be concentrated in such a way that only a DIN-A4-sized surface in the middle of the table is brightly lit. The LED evenly illuminates the required area, while everything else stays in the dark.
“A light-emitting diode is a single-point light source that emits light in a large, uncontrolled area,” says Dr. Christian Wenzel, head of department at the Fraunhofer Institute for Production Technology IPT in Aachen. “We use special lenses to direct all of the light to the place where it is needed, thus increasing the efficiency of the LEDs. The spot of light created by the light source does not therefore fade out at the edges, but has a sharply defined edge.”
This channeling of light is based on a free-form system of optics – a plastic lens whose geometry can be shaped in any way desired. “The lenses are cast using an injection-molding technique. The two halves of the tool that serve as a mold have to be aligned with extreme precision just once – they have an accuracy of a few microns, or less than a tenth of the diameter of a hair. Once the tools have been tared, the lens can be manufactured in large batches at low cost,” says Dr. Wenzel. The researchers at the IPT have optimized the entire process chain: from planning and manufacturing the lens systems to checking their accuracy. “There’s nothing like it anywhere else in Europe,” the expert claims. There is just one challenge that had to be mastered: The plastic, which is inserted into the mold when hot, shrinks as it cools – the finished lenses are therefore slightly smaller than dictated by the mold. The researchers take this effect into account by repeated, gradual improvement – to an accuracy of a few microns.
When the lenses are finished, the scientists check them. To do this, they project a pattern of stripes onto the lens. The distortion of the stripes reveals the curvature, inclination and shape of the lens.
The researchers will demonstrate the entire process chain along with optical systems for practical application at the Optatec trade fair in Frankfurt from June 17 to 20 (Hall 3, Stand D53).
Dr.-Ing. Christian Wenzel | Fraunhofer-Gesellschaft
Nano-scale process may speed arrival of cheaper hi-tech products
09.11.2018 | University of Edinburgh
Nuclear fusion: wrestling with burning questions on the control of 'burning plasmas'
25.10.2018 | Lehigh University
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Health and Medicine
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences