Coming soon: LED light- green tea cream to iron out wrinkles

Washington, Sept 10 (ANI): New treatment for facial wrinkles, which combines high-intensity light from light-emitting diodes (LEDs) and a lotion made of green tea extract, could emerge as an effective alternative to Botox and cosmetic surgery.

Scientists in Germany have reported a major improvement in their potential non-invasive technique for ageing lines. It works ten times faster than a similar anti-wrinkle treatment that uses LEDs alone, the researchers say.

The study is scheduled for the Oct. 7 issue of ACS’ Crystal Growth and Design, a bi-monthly journal.

Andrei P. Sommer and Dan Zhu point out that researchers have used light-therapy, or phototherapy, for more than 40 years to help heal wounds. Recently the scientists showed that use of high-intensity LEDs, similar to those used in automotive tail lights and computers, could help reduce skin wrinkles when applied daily for several months. ut exposure to intense LED light is also involved in generating high levels of reactive oxygen species as byproducts that can potentially damage cells. To combat that effect, the researchers combined the LED with a potent antioxidant in green tea extract called epigallocatechin gallate.

They applied a daily combination of LED light and green tea extract to the facial wrinkles of a human volunteer one month. The combination treatment resulted in smoother skin, including “less pronounced wrinkle levels, shorter wrinkle valleys, and juvenile complexion,” the scientists say.

The treatment showed promising results in only one-tenth of the time it took for LED therapy alone to reduce wrinkles. The study could form the basis of “an effective facial rejuvenation program,” and lead to a new understanding of the effect reactive oxygen species on cellular aging, they note. (ANI)

High-performance, low-cost green LEDs to brighten up the future

Washington, September 6 (ANI): A scientist is aiming to develop a high-performance, low-cost green LED (Light-emitting diode).

According to Christian Wetzel, professor of physics and the Wellfleet Professor of Future Chips at Rensselaer Polytechnic Institute (RPI), “Going green means different things to different people. For companies, going green means making a profit by selling equipment and services that allow one’s customers to be more efficient and reduce costs.”

“I’m doing both of those, but I’m also trying to make an LED that literally shines green light,” he said.

First discovered in the 1920s, LEDs are semiconductors that convert electricity into light.

When switched on, swarms of electrons pass through the semiconductor material and fall from an area with surplus electrons into an area with a shortage of electrons.

As they fall, the electrons jump to a lower orbital and release small amounts of energy. This energy is realized as photons – the most basic unit of light.

Unlike conventional light bulbs, LEDs produce almost no heat.

The color of light produced by LEDs depends on the type of semiconductor material it contains.

“We have high-performance red LEDs, we have high-performance blue LEDs, and if we paired them with a high-performance green LED we would be able to produce every color visible to the human eye – including true white,” said Wetzel.

“Every computer monitor and television produces its picture by using red, blue, and green. That means developing a high-performance green LED would likely lead to a new generation of high-performance, energy-efficient display devices,” he added.

“The problem, however, is that green LEDs are much more difficult to create than I, or anyone else, imagined,” he explained.

Simple preliminary attempts to create green LEDs, by merely adding more indium (In) to the gallium nitride (GaN) materials that composed blue LEDs, were unsuccessful.

The resulting green LEDs just weren’t strong or bright enough to stand toe-to-toe with red or blue.

Wetzel and his research group have been working to tweak precisely how to add more indium, and how to grow the structure more carefully into a device, with the goal of boosting the strength and light output of green LEDs.

“They’re endeavoring, he said, to close the green gap,” said Wetzel.

Once they overcome the challenge of developing efficient green LEDs, Wetzel envisions LED technology will quickly evolve from its current applications in signs and small displays and grow into a universally adopted, globally used replacement for traditional light bulbs and compact fluorescence tubes. (ANI)

Flexible high-resolution home theatre displays come closer to reality

Washington, August 21 (ANI): You may soon get to enjoy facilities like flexible high-resolution home theatre displays, wearable health monitors, and biomedical imaging devices because scientists are working on a novel process for creating new classes of lighting and display systems.

John Rogers, the Flory-Founder Chair Professor of Materials Science and Engineering at the University of Illinois, has revealed that the new process is all about creating and assembling ultrathin, ultrasmall inorganic light-emitting diodes (LEDs) into large arrays offers new classes of lighting and display systems with interesting properties, such as see-through construction and mechanical flexibility.

He said that such properties would be impossible to achieve with existing technologies.

“Our goal is to marry some of the advantages of inorganic LED technology with the scalability, ease of processing and resolution of organic LEDs,” said Rogers.

Compared to their organic counterparts, inorganic LEDs are brighter, more robust and longer-lived.

Organic LEDs, however, are attractive because they can be formed on flexible substrates, in dense, interconnected arrays.

Rogers and his colleagues-including collaborators from Northwestern University, the Institute of High Performance Computing in Singapore, and Tsinghua University in Beijing-say that the new technology combines features of both.

“By printing large arrays of ultrathin, ultrasmall inorganic LEDs and interconnecting them using thin-film processing, we can create general lighting and high-resolution display systems that otherwise could not be built with the conventional ways that inorganic LEDs are made, manipulated and assembled,” Rogers said.

To overcome requirements on device size and thickness associated with conventional wafer dicing, packaging and wire bonding methods, the researchers have developed epitaxial growth techniques for creating LEDs with sizes up to 100 times smaller than usual.

They have also developed printing processes for assembling these devices into arrays on stiff, flexible, and stretchable substrates.

To create an array, a rubber stamp contacts the wafer surface at selected points, lifts off the LEDs at those points, and transfers them to the desired substrate.

“The stamping process provides a much faster alternative to the standard robotic ‘pick and place’ process that manipulates inorganic LEDs one at a time. The new approach can lift large numbers of small, thin LEDs from the wafer in one step, and then print them onto a substrate in another step,” Rogers said.

The researcher says that shifting position and repeating the stamping process can transfer LEDs to other locations on the same substrate, and, in this fashion, large light panels and displays can be crafted from small LEDs made in dense arrays on a single, comparatively small wafer.

Given that the LEDs can be placed far apart and still provide sufficient light output, Rogers says that the panels and displays can be nearly transparent.

He even envisions the creation of flexible and even stretchable sheets of printed LEDs, which can have potential use in the health-care industry.

“Wrapping a stretchable sheet of tiny LEDs around the human body offers interesting opportunities in biomedicine and biotechnology, including applications in health monitoring, diagnostics and imaging,” Rogers said.

A research article describing the researchers’ work has been published in the journal Science. (ANI)

Next gen LEDs could shine bright white light for homes and offices

London, April 27 (ANI): The development of a new generation of white organic LEDs (Light-emitting diodes) could become the source of choice for homes, offices and even computer displays.

LEDs are preferable for many applications because they convert electrical energy into photons so efficiently.

While incandescent light bulbs convert only 5 per cent of the energy passing through them into light and compact fluorescent bulbs manage 20 per cent efficiency, LEDs routinely achieve 30 per cent or more.

The problem is that conventional LEDs produce light only at specific wavelengths, so manufacturers have had to employ two tricks to make white light.

One is to use several LEDs that each emit a primary colour. When combined, these colours look white to the human eye.

The other approach is to cover a blue LED in a phosphorescent chemical, or phosphor, that absorbs a portion of the emitted bluish light and re-emits it as amber.
gain, we see the combination as white.

Conventional LEDs produce light only at specific wavelengths. Making white light from them is costly.

These solutions are relatively costly, though.

Now, according to a report in New Scientist, a potentially cheaper option is emerging thanks to the development of organic dyes that emit blue and amber photons, and the ability to combine both in the light-emitting layer of an LED.

The result is an organic LED (WOLED) that produces white light directly.

WOLEDs have not made it out of the lab yet, however.

One problem is that high currents tend to break down the organic dyes they rely on and this dramatically reduces their lifetime compared with inorganic LEDs made of materials such as indium gallium arsenide.

One way around this would be to find a way to achieve an acceptable brightness with as low a current as possible.

Now, a group led by Dongge Ma at the Changchun Institute of Applied Chemistry at the Chinese Academy of Science has come up with a simple way of doing this: stacking two white-light-emitting layers in a single device so that they operate in series.

“The stacked structure allows higher brightness at lower current,” said Paul Burrows, an electronics engineer at Reata Research, a science and technology consultancy in Kennewick, Washington. (ANI)

New design for cheaper and more efficient white light LEDs

Washington, Apr 8 (ANI): In a bid to produce cheap and efficient white light for use in homes and offices, scientists at the Chinese Academy of Sciences have taken a major step towards developing a new type of light emitting diode (LED) made from inexpensive, plastic like organic materials.

Designed with a simplified “tandem” structure, the new LEDs can produce twice as much light as a normal LED, including the white light desired for home and office lighting.

“This work is important because it is the realization of rather high efficiency white emission by a tandem structure,” said Dongge Ma, who led the research.

Found in everything from brake lights to computer displays, LEDs are more environmentally friendly and much more efficient than other types of light bulbs, like incandescent bulbs and compact fluorescent bulbs, which waste much part of its energy as heat.

LEDs, on the other hand, are made from thin wafers of material flanked by electrodes and turn 20 to 50 percent, or even more, of the input energy into light. They also concentrate a lot of light in a small space.

While LEDs can easily be manufactured to produce light of a single colour — like red-with applications such as traffic lights and auto brake lights. But for indoor lighting, “natural” white light is needed.

This quality is measured by the colour-rendering index (CRI), which assigns a value based on the light source’s ability to reproduce the true colour of the object being lit. For reading light, a CRI value of 70 or more is optimal.

LEDs can produce white light by combining a mixture of blue, green, and red light, or by sending coloured light through a filter or a thin layer of phosphors-chemicals that glow with several colours when excited. But, these solutions increase costs.

Thus, to make inexpensive LEDs that can produce white light on their own, the researchers firstly built LEDs from organic, carbon-based materials, like plastic, rather than from more expensive semiconducting materials such as gallium, which also require more complicated manufacturing processes.

Then, they demonstrated, for the first time, an organic white-light LED operating within only a single active layer, rather than several sophisticated layers.

In fact, they even showed that by putting two of these single-layer LEDs together in a tandem unit, it was possible to achieve even higher efficiency.

The authors said that their LED could achieve a CRI rating of nearly 70-almost good enough to read by.

Progress in this area promises further reduction in the price of organic LEDs.

The study has been published in the latest issue of Journal of Applied Physics, published by the American Institute of Physics (AIP). (ANI)

Now, a robotic computer that can be operated by gestures

London, Mar 3 (ANI): Forget about using keyboard or mouse to operate your computer, for scientists have now developed a PC with a robotic neck that can be controlled only by gestures.

The music and game-playing gadget, called QB1 computer, was showcased at the Lift conference in Geneva last week.rederic Kaplan at the Swiss Federal Institutes in Lausanne said that conventional personal computers were too demanding, and people must generally sit to interact with one, and use both their hands and full concentration.

“Personal computers now tend to be used in casual settings, where the sitting position is actually unnatural,” New Scientist magazine quoted Kaplan as saying.

He pointed out that for playing music at a party, or using a computer to help cook a meal, the traditional interface of mouse and keyboard interface is not of much help.

He stressed that his QB1 computer, designed and built with industrial designer Martino d’Esposito, is less distracting.

Boasting a screen, QB1 doesn’t have any physical interfaces like a keyboard or a mouse.

The screen is fitted on a motorised robotic “neck” that tilts its monitor to face anyone nearby, like one person seeking eye contact with another.

In order to interact with QB1, users can only use hand and arm gestures, which are detected by a motion-sensing camera built into the screen.

Then, the gestures appear on the screen, which acts like a digital mirror so a user can see what their input is achieving.

In fact, the screen is fitted with a number of LEDS that illuminate the room with infrared light used by the camera to perceive depth and capture a rough 3D picture of its surroundings.

Thus, the computer can vary the size of text or other information on the screen as per the distance of the user.

Soon, volunteers will be testing prototypes of the device in their homes.

“These trials in real contexts are essential to turn QB1 into a real product. We wish to attract very different profiles of users, hopefully from different countries and cultural backgrounds,” said Kaplan. (ANI)