OLED technology is based on layers organic (carbon-based) chemical compounds that emit light when an electric current flows through the device. OLEDs are emissive devices, which mean they create their own light, as opposed to liquid crystal displays, which require a separate light source (backlight). As a result, OLED devices use less power and can be capable of high, higher brightness and fuller color than liquid crystal microdisplays.
Further power economies will be provided by Phosphorescent OLED (PHOLED) technology developed by UDC. PHOLEDs will attain up to four times greater efficiency than previously thought possible. Using the principle of electro-phosphorescence to convert up to 100% of the electrical energy in an OLED into light, such devices could be four times more efficient compared to current (fluorescent) OLED technology and up to ten times more efficient than backlit liquid crystal displays (LCDs).
OLEDs are “imprinted” on a silicon substrate. Since OLED is self luminescent and does not require back-lighting for operation, it is consuming significantly less power than alternative Liquid Crystal Displays (LCD). The active matrix silicon integrated circuits are imprinted directly under the display controlling the power to each organic point of light diode (pixel), performing certain image control functions at very high speed. OLEDs capability to refresh in microseconds rather than milliseconds, as LCD displays do, contribute to virtually flicker-free display in near-eye applications, resulting in smooth display even with highly dynamic motion video.
OLED technology has several advantages to the military user – since solid-state OLED displays do not use liquid crystal fluids, they instantly switch images on and off even at low temperatures (-40 degrees C) preventing image fade out at high temperatures (+65 degrees C). The OLED concept, patented by Kodak is not new, however, only in recent years it matured into practical technology, especially with the use of more efficient barrier layers (glass and other plastics), lower cost and extended lifespan of the luminescent organic materials.
In an effort to solve one of the critical OLED limitations, eMagin Corporation and the University of Michigan’s Solid-State Electronics Laboratory (SSEL) are studying novel approaches for thin-film encapsulation to enable the production of small, lightweight rugged displays and, potentially, flexible OLED displays. The program is funded by the Office of Naval Research as a Small Business Technology Transfer (STTR) rugged and reliable thin-film encapsulation method for OLED displays. According to Susan Jones, executive vice president and chief marketing officer, at eMagin, this research could foster new generations of rugged, lower cost encapsulation techniques that could be applied to the production of micro-displays as well as larger format OLED devices.”
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