Power consumption - Page 15

The US Department of Energy (DoE) announced new SBIR and STTR grants for solid state lighting projects. The DoE announced five new grants out of which two are related to OLED technologies.

Pixelligent Technologies were awarded an SBIR project titled "Light Extraction for OLED Lighting with 3-D Gradient Index". This project will explore the application of a novel and unique 3D gradient index (GRIN) layer to improve the efficiency and lifetime of OLED devices. Using such a unique structure, OLEDs could be produced that achieve the theoretical maximum extraction efficiency.

During the International Display Workshops that was help a few weeks ago in Fukuoka Japan, LG Display discussed its new WOLED tandem stack that it plans to introduce soon to its OLED TVs and lighting panels.

LG Display says that its new stack is a "3-stack-OLED" while its existing stack is a "2-stack-OLED". As you can see in the image above, LG apparently counts each emissive layer as a different stack in this case.

Researchers from the Fraunhofer FEP announced a new development that can reduce the power consumption of OLED microdisplays. The power reduction is enabled by new chip and control electronics, that now only handles pixel changes and does not refresh the entire display all at once.

The researchers say that this development enabled a drastic reduction in power consumption - which is somewhat surprising. The new microdisplays (which are monochrome - green) use 1 to 4 mW, which they say is a fraction of the power consumed by the Fraunhofer's previous generation display - a color (WOLED+CF) bi-directional OLED (so this is not a fair comparison of course).

Italy-based DesLabs launched a new product called WiNEOLED - which is an OLED lamp dedicated for wine professionals and amateurs. The idea is that the excellent lighting properties and the uniformity of the OLED panel will unveil the wine's properties like never before.

The WiNEOLED uses an LG Display panel that offer a CCT of 4000K, an efficacy of 55 lm/W and a brightness of 75 lumens. The CRI is over 90 and the lifetime is 30,000 hours (LT70). The lamp can be powered with a USB cable, a battery or via a wireless Qi charging based.

The US DoE published a new CALiPER report made by the PNNL laboratory, with photometric testing, laboratory teardowns and accelerated lifetime testing of OLED luminaires. As you can see in the photo below, the four luminaries (from top-left, clockwise) are the OTI Aerelight, Acuity Brands Chalina and Acuity Brands Nomi (single panel and dual panel).

The report contains a lot of interesting information (see the link below to access the PDF). The PNNL researchers find that efficiency of OLED luminairies is still low compared to LED lamps - ranging from 23 lm/W to 45 lm/W. The OLED panels themselves are more efficient (42 - 55 lm/W) but the reduction in efficiency is mostly due to very inefficient transformer and driver selections and combinations.

OLEDWorks announced that the Brite 2 OLED panels are now available. The company's latest OLEDs, announced in March 2016, offer a brightness of 300 lumens, a high CRI (>90) and an efficiency of 60 lm/W.

The Brite 2 OLED comes in either 3000K or 4000K, and is now available as part of a promotion kit which includes four panels for $199.

In April 2016, Japan's Semiconductor Energy Laboratory (SEL) and Advanced Film Device announced they have developed a hybrid OLED - reflective LCD display, that can switch between an OLED mode (for dark environments) and reflective LCD mode (for sunlight visibility). Such a display could be very power efficient.

TR-Hybrid in OLED mode

SEL demonstrated a prototype display at SID 2016, and provided more information. SEL calls these displays TR-Hybrid displays (TR means Transmissive OLED and Reflective LC). To create this display, SEL introduced holes into the reflecting electrodes of a reflective LCD, and the OLED layer beneath transmitted light through these holes in OLED mode.

The US Department of Energy (DOE) released a report on its first OLED lighting demonstration (GATEWAY) project. The report summarizes the experience at Aurora Lighting Design, a company based in Grayslake, IL, that installed Acuity Brands' Trilia OLED lighting system in September 2014.

On the plus side, the DOE report says that OLED lighting has a appearance that expresses creativity and innovation, making a statement to Aurora Lighting Design clients who visit the offices. The color quality is high, and the employees enjoy working under the system. The exposed OLED panels deliver a soft, minimal-shadow lighting that makes faces and expressions visible, and increases room brightness by delivering light to vertical surfaces.

Researchers from Korea's Advanced Institute of Science and Technology (KAIST) have managed to create OLEDs that feature a 60% increase in light extraction efficiency and a 15% wider viewing angles.

To create these OLEDs, the scientists investigated the optical properties of the firefly's light-emitting cuticle which is patterned with tiny hierarchical structures. Out of all light-emitting animals, the firefly makes light in the most efficient way.

OLED material developer Molecular Glasses announced that its phosphorescent host material was demonstrated to improve the lifetime of OLED devices by up to 1,500%, with external quantum efficiency of 20% and minimal luminance roll-off. This is in comparison to the "state-of-the-art phosphorescent host mCBP".

It is not clear to which host this is compared to, but the company says that these results were obtained following a 96 prototype device experiment that was recently completed at OLEDWorks' DOE approved laboratory.