Using a semi-spherical highly-refractive lens to enhance light extraction, and an OLED device measuring just 2mm x 2mm a luminous efficiency of 128lm/W was achieved
Panasonic Electric Works Co Ltd recently announced the company has successfully produced an OLED device with a luminous efficiency of 128lm/W. Technical progress was presented at the recently held 72th Meeting of the Japan Society of Applied Physics.
Panasonic Electric Works has achieved this efficiency by dramatically improving light extraction techniques for white organic light emitting diodes (WOLEDs). Specifically, the company inserted a light extraction layer composed of a highly-refractive material between a light-emitting layer and a glass substrate, a high-reflectivity material for the metal on the back side was also adopted.
To push efficiency Panasonic Electric Works made detail calculations on the perfect device structure to determine the optimal position of each light-emitting layer and designed the OLED device accordingly. This approached reduced the total reflection inside the device and doubled light extraction efficiency to about 40%.
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