POWER CONSUMPTION

UniversalPHOLED™ technology and materials have become recognized for their key role in making OLEDs well suited for battery-operated, mobile display applications. Perhaps less obvious, however, is the advantage that PHOLEDs can offer to large-area TVs and lighting. To demonstrate this advantage, we modeled the power consumption of an active-matrix OLED (AMOLED) using PHOLED versus fluorescent OLED (FL-OLED) technology.

PHOLEDs have higher luminous efficiencies than FL-OLEDs - by up to a factor of 4. This means that a PHOLED needs much lower electrical current to achieve the same pixel brightness as a FL-OLED does. In an AMOLED, PHOLEDs reduce the power consumed by both the OLED and the thin film transistor (TFT) backplane.

The following charts show the significant power savings that can be achieved through the use of red, green and blue PHOLEDs in 3.5" and 40" diagonal displays, representative of smartphone and TV applications, respectively.

Low temperature rise
Because electrical energy that is not converted into light is converted into heat, displays and lights generally experience a temperature rise while operating. This elevated temperature becomes especially palpable in a large-sized OLED TV or light. PHOLED technology can dramatically reduce this increase. For example, the temperature rise in the FL-OLED would be about 30°C while the temperature rise would be reduced to 10 - 17°C with PHOLED technology (assuming a 40” diagonal AMOLED). Lower temperature rise is important. It prolongs OLED lifetime as degradation is temperature dependent. It also reduces the amount of air-conditioning required to remove the generated heat - making PHOLED technology a great element in any “green” or environmental building strategy.

Backplane compatibility
Today, amorphous silicon (a-Si) backplane technology is the incumbent with a mature, low-cost installed manufacturing base. Low temperature polycrystalline silicon (LTPS), a relative newcomer, uses more complex processes that still operate with lower production yields than a-Si. However, LTPS is higher performance - offering higher carrier mobility so that driving circuitry can be integrated directly onto the substrate for lower cost, esp. for small-area displays. Conventional wisdom has also suggested that the higher mobility of LTPS would be required to meet OLED's high current drive conditions. This was the case until PHOLED technology was developed. The lower current drive of a PHOLED reduces the power consumed in the TFT backplane, thus reducing its mobility requirements. As a result, PHOLED technology has become a key enabler for the possible use of a-Si backplanes in large-area displays. In the future, PHOLEDs may also help enable the adoption of lower-cost organic TFTs.