Since Tang discovered a blue glow in organic material in 1979 OLEDs and their production processes have been constantly developed. The latest OLEDs are flexible. They are based on polymers and are applied to a film.
In 1979 Chin Tang discovered electroluminescence in the research department of
Kodak. During his work with solar cells he observed a blue glow of organic material.
In 1987 Tang and Van Slyke introduced the first light emitting diodes from thin
organic layers. In 1990 electroluminescence in polymers was discovered.
The first OLEDs were organic light diodes from small molecules coatable in vacuum
(small molecule or SM-OLED). The later OLEDs are organic light diodes on the basis
of polymers which are applied in liquid phase (Polymer-OLED or PLED). Polymer-LEDs
developed by Cambridge Display Technology allow the solution of organic material in
liquid. Afterwards, the organic material can be applied by spin coating or in an
inkjet printing processing. At present polymer LEDs still lag behind in picture
quality but they promise considerably less production costs. The printing process
is more flexible.