Transparent OLED displays on the way
German researchers at the Technical University of Braunschweig are developing
a technology that will enable completely transparent organic
light-emitting diode (OLED) displays. The researchers' approach is
unique, and they are claiming it to be a world first.
Their approach is to use transparent TFTs (thin-film transistors) made
of a 100-nanometer-thick layer of zinc-tin-oxide, which transmits more
than 90 percent of visible light. Such transistors are more often made
of silicon, which is used for LCDs (liquid crystal displays) but is
highly absorptive in the visible part of the spectrum.
In the transparent displays, the TFTs and the OLED pixels are positioned
next to each other. The OLED pixel can be placed on top of the TFT
driver circuit without interference.
Experimental devices using the technology have also achieved brightness
levels of up to 700 candelas per square meter (cd/m²), compared to
only around 300 cd/m² for traditional LCD displays. Despite this,
the technology allows production with conventional techniques and at low
temperatures, enabling the use of "cheap, flexible plastic substrates."
Thomas Riedl, a research head at the University of Braunschweig, says
working transparent OLED prototypes will be available in only two years,
although he did not give an estimate for eventual shipping products.
Thanks to Ars
for the tip.