ENTERTAINMENT FEATURE
An OLED device with a blue pixel
using materials from Cynora. Cynora aims
to release its first blue OLED emitters by the end of this year
“The only company currently manufacturing OLED television panels is LG… No other company will be able to offer OLED panels any time soon”
almost perfect black levels on a pixel-to- pixel basis – a feat unachievable by the majority of display technologies. While OLED displays promise a range of
new compelling features that consumers have already shown great interest in – it is popular opinion that OLEDs currently produce the highest WCG picture quality in 2017, according to Virey – they’re uptake over the next five years will be limited to 12 million units per year, Yole analysts have predicted, because of constrained manufacturing capabilities worldwide. It is expensive and complicated to fabricate OLEDs, which makes it challenging for existing television makers to produce their own OLED displays. ‘The only company currently
manufacturing OLED television panels
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is LG,’ stated Virey. ‘Many OEM brand televisions are offering OLED models, but these are all using LG panels. No other company will be able to offer OLED panels any time soon, at least not before 2019 to 2021. In order for any other company to do this, they would have to both master the development of OLED technology and then build entire new production facilities, costing billions of dollars.’ One format of LG’s OLED technology,
according to Virey, incorporates colour filters similar to LCDs, which filter light from white OLEDs to produce a wide range of colours and exceptional picture quality. OLED displays can also be made without colour filters, however, using a combination of red, green and blue LEDs in each pixel to give a wide colour gamut. While this format also shows promise, at present blue OLEDs suffer from efficiency and longevity problems.
Something blue The inefficiency of current fluorescent blue OLED emitters is having a negative effect on the efficiency of entire OLED displays, according to Joanna Wrzeszcz, marketing
officer at OLED material manufacturer Cynora. The cause is a lack of suitable efficient fluorescent or phosphorescent material for blue OLED production. Wrzeszcz explained: ‘The fluorescent
material is stable but has a very low efficiency, while the phosphorescent technology used for efficient red and green emitters is unfortunately not successful for deep blue material [because of a short lifetime].’ Cynora has therefore developed its own blue emitters using materials designed to reduce electrical stress within the OLEDs via thermally activated delayed fluorescence (TADF) technology. These materials can convert both singlet and triplet excitons into light energy within the multiple layers of OLEDs, with triplet excitons having proven challenging to convert in the past. As a result the emitters are able to offer both long lifetime and high efficiency. ‘Our efficient blue TADF materials will
enable device makers to provide OLED displays with significantly reduced power consumption [up to a factor of two] and higher display resolution,’ said Wrzeszcz. The development is so promising that LG
g November 2017 Electro Optics 15
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