Technology Development May Lead to Television Screens You Can Carry with You

Julieta Gonzalez
July 18, 2000

Portable, flexible, fold-up TV screens? Sound far-fetched? Not exactly. According to Ghassan Jabbour, assistant research professor in the Optical Sciences Center at the University of Arizona, continued research and development of organic light-emitting devices (OLEDs) may provide such practical applications.

The OLEDs, says Jabbour, are more cost effective and easier to produce than the conventional liquid crystal light-emitting diode (LEDs). Also, they have more appealing attributes over liquid crystals presently used in laptop display monitors and other electronic appliances.

"The organic light-emitting device emits its own light and allows for sunlight-readable displays with wide viewing angle as opposed to liquid crystals which do not emit its own light but rather use an external light source," says Jabbour, "they cannot be clearly viewed under sun light and have a narrow viewing angle. An additional feature that is unique to OLEDs is the ability to make them on a flexible substrate such as Saran wrap, for example."

There is a potential for making OLEDs using cost-effective technologies such as screen printing. The actual screen printing which is used to make the film required for the fabrication of the OLEDs is not new. It's the basic technique used by screen printers for centuries using a frame, a fabric, a design stencil ink and a squeegee.

For example, a polymer-molecular blend acting as the ink is deposited unto several substrates situated under the screen in direct contact with the fabric. This process will yield a very thin film that is used as one of active layers in OLEDs. Using screen printing, however, Jabbour and his team were able to make for the first time ultra thin films that are nearly a thousand times thinner than the human hair. The organic materials themselves acted as the ink in this case. Members of Jabbour's team include Dino Pardo, Rachel Radspinner and Nasser Peyghambarian.

The beauty of screen printing, says Jabbour, is "its versatility, ability to print almost on any surface, low cost and production speed." Jabbour cautions, however, that the work is still in its early development and requires further research and investigation to allow for more fundamental understanding and optimization of the fabrication process to assess its potential in making reliable devices.


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