Fujifilm/imec partnership yields OLED manufacturing breakthrough

Researchers from a partnership between imec and Fujifilm have shown full-color organic light-emitting diodes (OLED) made using a newly developed photoresist technology for organic semiconductors that enables submicron patterning. This breakthrough result paves the way to establishing cost-competitive manufacturing methods for high-resolution and large organic electroluminescent displays and establishing cost-competitive manufacturing methods.

Organic EL displays can be made thin and flexible and provide excellent response time and contrast ratio – making them very attractive for 4K televisions, full HD mobile devices, and compact displays for wearable devices. In 2013, Fujifilm and imec jointly developed photoresist technology for organic semiconductors that enables submicron patterning without damaging the organic semiconductor materials, based on photolithography capable of high-resolution patterning on large substrates. The technology attracted wide attention since it used an existing i-line exposure system and offered a cost-effective way of manufacturing high-resolution organic semiconductor devices.

These results open new opportunities, such as using the photolithography in a multiple patterning process. An example would be creating an OLED array that adds a fourth color to red, green and blue, as well as developing previously-unseen devices such as a new sensors that integrate OLED with the organic photodetector.

Fig 1:  OLED array forms a pattern with a sub-pixel pitch of 20 µms. UV illumination of the array shows RGB dots.

With the latest achievement they successfully verified array performance. Red, green and blue organic EL materials were patterned, each in the subpixel pitch of 20 μm. An OLED array of 40 x 40 dots at the very high resolution of 640 ppi was produced.