Fujifilm Corporation and nano-electronics research institute, imec reported that they demonstrated full-color OLEDs. The full color-OLEDs employed their jointly-developed photoresist technology that enables submicron patterning of organic semiconductors. Fujifilm contends that the breakthrough result paves the way to producing high-resolution and large, organic Electroluminescent(EL) displays and establishing more economical manufacturing methods.
Organic EL displays, which can be made thin and flexible, are increasingly used for mobile devices including smartphones and wearables, and televisions. They reportedly offer excellent response time and contrast ratio. The pixel density required depends on the application. Organic EL displays of the high pixel density of around 200ppi are needed for 4K televisions, 500ppi is needed for full HD mobile devices, and even higher density is required for compact displays for wearable devices.
In 2013, Fujifilm and imec jointly developed the photoresist technology for organic semiconductors that enables submicron patterning without damaging the organic semiconductor materials. The technology employs an existing i-line exposure system for photolithography that is capable of high-resolution patterning on large substrates.
Fujifilm and imec successfully verified the performance of the red, green, and blue OLED materials that they produced. Each color organic EL material was patterned in the subpixel pitch of 20μm. An OLED array of 40 x 40 dots at the resolution of 640ppi was created and illuminated with UV rays to confirm that blue, red, and green dots separately emitted light. A test involving the application of a voltage rather than illumination also confirmed the emission of blue, red, and green lights.
The technology opens the possibility of adding a fourth color to red, green and blue, as well as developing previously-unseen devices such as a new sensors that integrate OLEDs with an organic photodetector.