Technical / Research - Page 21

Korea's Institute of Science and Technology (KAIST) and the country's Engineering Research Center (ERC) are jointly establishing a new OLED light therapy engineering center.

The new R&D center will initially target skin wound treatment and sleep disorder treatment, using flexible OLEDs to replace current LED-based solutions. In the longer range, the center will also look into dementia prevention and treatment, mild cognitive impairment solutions and other diseases.

Researchers from Korea's National University developed a new process based on high-pressure gas sprays that can be used to rapidly transfer OLED layers very quickly - which could reduce the manufacturing time of OLED panels by 90%.

The new process uses a new air jet technology that sprays desquamating gas such as nitrogen, argon and air at high pressures. The gas is sprayed at a speed of 300 m/s between the OLED and a substrate - which reduces the binding power of the OLED from the substrate, and increases the binding energy of the organic layers being transferred. This can be used to quickly transfer thin films without damage them.

Researchers from Kyushu University's Center for Organic Photonics and Electronics Research (OPERA) developed a new TADF emitter molecule that is based on excited-state intramolecular proton transfer (ESIPT).

The researchers says that ESIPT can be used to design completely new TADF materials, which could enable researchers to achieve a high performance and long-lasting emitter structure, as a new material family may expand the molecule design possibilities. TADF from a ESIPT molecule has been reported previously - but the researchers say that this is the first demonstration of highly efficient TADF observed inside and outside of a device.

Fraunhofer FEP and Sefar developed a roll-to-roll processed large-area flexible OLED lighting panels in a joint project. This achievement followed a batch-based flexible OLED panel demonstrated in early 2017.

The R2R process currently used enables Fraunhofer and Sefar to produce 30 cm wide OLEDs in lengths of up to 30 meters.

Researchers at the University of California, Santa Barbara and the Dow Chemical Company have chosen a bottom-up approach to patterning emissive polymers, aiming to solve some of the problems that plague Solution-based protocols for OLED manufacture.

The team started with a layer of indium tin oxide and used light-activated chemistry to pinpoint specific locations on the surface for polymer growth. Key to the success of this approach are designer iridium photocatalysts that serve two roles: First, as the catalyst to build the emissive brush polymers, and then as a necessary dopant for the resulting OLED arrays.

OLEDON announced that it has developed a plane-source evaporation shadow mask process that can achieve a shadow distance of 0.38um - which can enable OLED display resolution to reach 2,250 PPI. The company says it technology will be able to achieve 3,300 PPI in the future.

OLEDON is not alone in the development of plane-source evaporation technology. In November 2016 Sunic Systems announced that it developed a similar AMOLED production process - that can also achieve 2,250 PPI. It may be that Sunic and OLEDON are collaborating on this, it is not clear.

Oculus developed a new way to improve extended focus depth issues with VR HMDs. The so-called focal surface display augments a regular HMD setup by using a spatially programmable focusing element placed between the eyepiece and the underlying color display.

Oculus's prototype unit uses an eMagin WUXGA (1920×1200) 60 Hz color microOLED display. Oculus is currently using SDC's AMOLED displays in its commercial HMDs. It is great to see the company experimenting with microOLED displays as well, even if these are just prototypes at this stage.

The Fraunhofer FEP institute in Germany first unveiled its bi-directional OLED microdisplays in 2012 with the novel idea of embedding photo detectors between the OLED pixels. Since then the instituted demonstrated its second-generation microdisplay that supported a resolution of 800x600 (SVGA), up from VGA in the first generation prototypes.

The Fraunhofer FEP now announced that it developed a new generation of these displays, that employ an extra-think encapsulation layer, which can turn these new displays into fingerprint sensors. The idea is that the OLED display illuminates the fingers and then the reflected light is used to detect and analyze the fingerprint with excellent accuracy.

The EU launched a new project called HyperOLED with an aim to develop materials and matching device architectures for high-performance, hyperfluorescence TADF OLED emitters. HyperOLED is coordinated by Merck, and the project partners include MicroOLED and the Fraunhofer IOF institute. This three years project received a €4 million grant from the EU.

These OLED emitters will be realized by combining TADF molecular hosts with novel shielded fluorescence emitters, targeting saturated blue emission of very high efficiency at high brightness. The project will also achieve efficiency gains through molecular alignment to enhance light outcoupling.

TADF are getting a lot of attention now, as a promising new emitter type that could finally enable efficient blue emission, and also efficient alternative to red and green phosphorescent emitters.

Several new TADF research papers have been announced by SID and will be presented at DisplayWeek 2017. Below you will find a list of these recent achievements, at no particular order.