Power consumption - Page 1

As OLED is an emissive display technology, an OLED pixel only draws power when it is used - and the brighter it is, the more power it consumers. This of course means that adopting a dark UI is better for your device's power life.

During Google's recent Android Dev Summit, the company detailed the power consumption of the OLED display used in its 2016 Pixel smartphone (an SDC FHD 5" AMOLED). As you can see in the image above, the power consumption is different for each color (with red being the most efficient color and blue the least efficient). Surprisingly the display draws quite a bit of power even when completely black.

Researchers from Korea's KAIST research institute developed a high-efficiency OLED architecture that uses external scattering medium to achieve an EQE greater than 50%.

Such high EQE was only demonstrated before using complex internal nanostructures or by employing a micro-lens array, but these solutions are complicated to produce and can hinder the OLEDs flexibility and planar structure. The researchers say that their scattering approach maintains the planar geometry , results in flexible OLEDs and can be easily scaled to enable low cost production.

Researchers from Japan's Kyushu University developed a new technology called singlet fission that enables near-infrared OLED materials to surpass the 100% limit for exciton production - or achieve an internal quantum efficiency (IQE) of over 100%. Singlet fission was already used in OPVs, but this is the first time that it was demonstrated with OLEDs.

Achieving over 100% is possible because at 100% IQE all charges form excitons that emit light. The new technique splits the energy from a high-energy excitons into two low level ones. The new OLED emitter materials use molecules in which singlets can transfer half of their energy to neighboring molecules while keeping half of the energy for themselves - each singlet creates two triplets. The emitters emit near-infrared light.

Researchers from the University of Michigan developed a new method to cost-effectively extra more light out of OLED displays. To achieve that, the researchers used a Sub-Electrode Micro-Lens Array (SEMLA) placed between the bottom transparent ITO electrode and the glass substrate. Testing on green and white PHOLEDs, the researchers say the SEMLA enhanced light output by a factor of 2.8 (green) and 3.1 (white) compared to a similar device without the lens array.

The researcher say that such an array can be fully transparent and has no impact on the sharpness of the display. The hexagonal array of 10 μm lenses can be fabricated using conventional photolithography methods which are quite cost effective. Such a micro-lens array does not change the actual OLED production process.