Flexible OLED (FOLED) : The Next Generation of Display Technology
Flexible OLED ( Flexible Organic Light Emitting Diode) is a type of OLED where an electroluminescent organic material is deposited onto a flexible special type of plastic. This allows the display to be rolled up or bent during usage. Regular OLEDs are fabricated on a glass substrate. Use of plastic as the medium makes FOLEDs lightweight and bendable. Flexible OLED is the technology that is going to revolutionize digital devices in the near future. Flexible OLEDs (FOLEDs) may be used in manufacturing rollable electronic papers, curved displays that may be used in big malls, flexible tablets, flexible phone displays and much more.
Electronic paper displays which can be rolled up have been developed by E Ink (E Ink Corporation is a privately held manufacturer of electrophoretic displays (EPDs)) . At the CES 2006, Philips showed a rollable display prototype whose screen can retain an image for several months without electricity.
Samsung Electronics’ vice chairman Kwon Oh-hyun told Korea Times that demand is high for the futuristic OLEDs, with mass production beginning in late 2012. It is a well known fact that Apple is in discussions with Samsung to produce mass volumes of OLED screens to be used in some of the Apple products. May be an iPad or iPhone. ”OLEDs will replace LCDs as the main mobile displays from around 2015 as the screens are thinner and brighter”. Samsung has revealed that its big-screen OLED (55-inch) TV is due for launch in the second half of the year 2012. Future looks very promising for the FOLED technology.
The organic material used in FOLEDs can degrade over time due to environmental factors like moisture and air. Ordinary OLEDs uses glass to seal the organic materials and glass provides good protection from moisture and air. The plastic substrate used in FOLEDS is not as effective as glass in providing protection from environmental factors.New Encapsulation methods are being actively researched to improve the quality and durability of FOLEDs.
Department of Electrical and Electronic Engineering, Yonsei University have developed a novel encapsulation method for flexible organic light-emitting diodes (OLEDs) using poly(dimethylsiloxane) (PDMS). The new method, which uses polycarbonate film, silicon dioxide, and PDMS, was found to enhance the lifetime of OLEDs in air.
Optical measurements of the preservation of calcium films encapsulated with PDMS showed that the water and oxygen permeation rates of the PDMS encapsulation were reduced from a level of 0.57 g m-2 d-1 (bare substrate) to 1×10-7 g m-2 d-1. These results show that the PDMS barrier coatings have a good potential for flexible OLED applications.
Chinese science bulletin has published a research paper on a new hybrid encapsulation technique. This hybrid approach uses Alq3/LiF layers as the pre-encapsulation layer and a flexible aluminum foil coated with getter as the encapsulation cap.
Future of FOLEDs looks very bright and we are going to witness a new revolution in display devices in the near future.
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