Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Photonics: Think thin, think vibrant

30.08.2012
Flat panel displays and many digital devices require thin, efficient and low-cost light-emitters for applications. The pixels that make up the different colors on the display are typically wired to complex electronic circuits, but now researchers at A*STAR have developed a display technology that requires a much simpler architecture for operation.

Flat panel displays, mobile phones and many digital devices require thin, efficient and low-cost light-emitters for applications. The pixels that make up the different colors on the display are typically wired to complex electronic circuits that control their operation.


Schematic of the tunable color filter. The combination of a gold film with ring-shaped holes and the use of liquid crystals (red and green) enables pixels of a defined color that can be turned on and off. © 2012 Y. J. Liu

Jing Hua Teng at the A*STAR Institute of Materials Research and Engineering and co-workers have now developed a display technology that requires a much simpler architecture for operation. They demonstrated that combining a thin perforated gold film with a liquid crystal layer is all that it takes to make an efficient color filter.

“Our color filters are a lot thinner and more compact than conventional thin-film-based color filters,” says Teng. “The colors of these filters can be tuned with ease so they are very versatile in applications.”

The color selection of the devices comes from the patterned gold film. The collective motions of the electrons on the film surface — the so-called surface plasmons — absorb light at wavelengths that depend on the details of these patterns. In the present case, the patterns are narrow, nanometer-sized rings cut out of the films (see image). As the diameter of the rings changes, so does the color of the metal film. Pixels of a different color can be realized simply by patterning rings of different sizes across the same gold film.

To realize a full display, however, each of these pixels needs to be turned on and off individually. This is where liquid crystals come in.

Liquid crystals are molecules that can be switched between two different states by external stimuli, such as ultraviolet light. In their normal state the crystals let visible light pass through so that the pixel is turned on. But when ultraviolet is also present, the structure of the liquid crystal molecules will change so that it absorbs visible light (i.e. the pixel is turned off). This process can be repeated over many cycles without degrading the device itself.

Although the device works in principle, it remains a concept on the drawing board for now. This is because there are still many issues that need to be overcome, for example, the optimization of the switching speed and the contrast between ‘on’ and ‘off’ states. In future work, the researchers will need to extend their ideas so that their device can serve a larger area and produce the fundamental colors red, green and blue.

Teng and his team are quite optimistic that they will achieve this soon.

The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering.

References:

Liu, Y. J., Si, G. Y., Leong, E. S. P., Xiang, N., Danner, A. J. & Teng, J. H. Light-driven plasmonic color filters by overlaying photoresponsive liquid crystals on gold annular aperture arrays. Advanced Materials 24, OP131–OP135 (2012).

A*STAR Research | Research asia research news
Further information:
http://www.research.a-star.edu.sg
http://www.researchsea.com

More articles from Materials Sciences:

nachricht Manchester scientists tie the tightest knot ever achieved
13.01.2017 | University of Manchester

nachricht CWRU directly measures how perovskite solar films efficiently convert light to power
12.01.2017 | Case Western Reserve University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>