OLED Lifetime: introduction and market status - Page 14

IDTechEx released a new OLED lighting report (OLED vs LED lighting 2013-2023) in which they analyze the OLED lighting market, and compare it to the LED market. The company says that in the "most likely" scenario, the OLED market will grow to $1.3 billion in 2023.

According to IDTechEx, there are two main issues with OLEDs. First of all the performance: LEDs last much longer (typically 50,000 hours compared to 5,000-15,000 in current OLED panels) and they are more efficient (90-100 lm/W compared to OLED lighting which is currently at 20-50 lm/W). Personally I think this gap will close in time. LG Chem for example are expected to release new panels in July 2013 which will feature 80 lm/W and 20,000 hours (LT70).

Panasonic Corporation developed a white OLED lighting panel that is the world's highest luminous efficiency - 114 lm/W for a light-emitting area of 1 cm². Panasonic also developed a larger panel (25 cm²) with 110 lm/W. The panels also feature long lifetime - over 100,000 hours (LT50) and a brightness of of 1,000 cd/m². The panel thickness was less than 2 mm.

Panasonic 114 lm/W OLED panel

To achieve this high efficiency, Panasonic focused on an all-phosphorescent design (with an optimal stacked layer design) and new light extraction technology. Panasonic used a Built-up Light Extraction Substrate (BLES) by optimizing the arrangement of the film, glass and air to suppress light confinement in the OLED. This enable them to achieve about 2.5 times improvement in the light extraction efficiency, which is about 50% in the new panels. Panasonic says that in older technology the light extraction efficiency stayed below 40%. Panasonic says they hold 30 patents in Japan and 17 overseas - all related for this new development.

Ignis Innovation announced that samples of its 20" 1296x768 (XGA) AMOLED display will be available in August 2013. Ignis will offer these samples to display makers for evaluation of Ignis' MaxLife compensation technology in their own displays (more on this below). They will sell the display for low volume, demanding applications such as medical imaging and scientific imaging.

The 20" AMOLED panels use a-Si backplane and are made by RiTdisplay. The panels are only 1.3mm thick (the complete display module is 3 mm thick). The refresh rate is 240Hz.

Universal Display reported their financial results for Q1 2013. Revenues were $15 million (up 19% compared to Q1 2012) - with a 40% increase in commercial material sales, mostly due to the fact that Samsung Display Corporation (SDC) adopted UDC's green PHOLED (host and emitter) in the 5" Full-HD Super AMOLED dipslay used in the GS4 smartphone (shipments of these new materials started in March). UDC reported a net loss of $4.8 million in the quarter.

Guidance and cash

UDC did not change their revenue guidance for 2013 - it will be in the range of $110 - $125 million (32% to 50% increase over 2012). This includes a $40 million license free from SDC. They assume that the OLED market will grow to over $10 billion in 2013 (they use DisplaySearch estimates). UDC has around $220 million in cash and they used $10.9 million in the first quarter.

When Samsung launched the GS4, they said the Super AMOLED display uses PenTile. Back in January, it was reported that Samsung will adopt a new subpixel scheme that uses diamond sub-pixels, but up until now we didn't hear anything official from Samsung. Today the company finally did acknowledge the new design, and published two closeup photos of the GS4 display.

Diamond Pixel, as Samsung's calls their new design, is a PenTile subpixel scheme, in which there are twice as many green subpixels as there are blue and red ones. The green subpixels are oval and small while the red and blue ones are diamond-shaped and larger (the blue subpixel is slightly larger than the red one). DisplayMate says that this is because green is the most efficient (and long lasting) OLED emitter while the blue has the shortest lifetime.

At CES 2013 Panasonic unveiled a 56" 4K (3840x2160) OLED TV panel prototype that was produced using an all-printing method. Back in January we assumed Panasonic were using SMOLED materials, but now Sumitomo Chemical revealed (as part of their 2013-2015 plan presentation) that this TV prototype used the company's PLED materials.

Panasonic has been working on OLED printing technologies for quite some time and back in 2009, they teamed up with Sumitomo to jointly-develop OLED TVs, based on Sumitomo's PLED materials and technology. I thought this partnership is not active anymore, but evidently I was wrong on that one.

NEC Lighting developed transparent OLED lighting panels that use a transparent ITO film - and they plan to commercialize these panels by 2015. The company unveiled a prototype 20x20 cm panel that features 70% transmittance, 35 lm/W efficacy and 20,000 hours lifetime (not sure if that's LT70 or LT50). This panel was developed in collaboration with Japan's New Energy and Industrial Technology Organization (NEDO).

Last week NEC Lighting announced that they developed the world's most efficient OLED device to day at 156 lm/W.

Back in June 2012 I reported from SID on Ignis' Max Life technology. Max Life provides external compensation - that deals with OLED burn-in. The idea is to keep track of how much each pixel was used, and so it's possible to calculate the brightness loss in that particular pixel, and then drive this particular pixel correctly - to compensate. Ignis now released a nice video showing a 20" AMOLED panel (their own a-Si prototypes made by RiTDisplay) with a burn-in logo. When Max Life is turned on, the logo disappears:

Ignis explains that while Max Life theoretically makes the "eventual" lifetime (until the display burns out completely) worse, in practice it helps to make the device usable longer. Ignis says that the main problem is non-uniformity in brightness and not actual brightness.

Researchers from the Japanese National Institute of Advanced Industrial Science and Technology (AIST) developed a new method to selectively measure the behavior of specific molecules at the interfaces of organic layers in a multilayered OLED device - while the device is emitting light, and without harming the device. This can be used to study the deterioration of materials and interface in the OLED and enable improving the device's lifetime easier.

The researchers used advanced laser spectroscopic technique to measure the molecular vibrational spectrum at each layer interface. More specifically, they have used sum frequency generation (SFG) spectroscopy. AIST developed a two-color SFG spectroscopy that uses wavelength-tunable lasers.

The three-year long NEMO (NEw Materials for OLEDs from solutions) project has been successfully concluded. Merck, the project's leader, says that the new soluble materials developed in the project can now be used in large-area OLED display and lighting panels. The new phosphorescent materials have an increased lifetime (200,000 hours for green) and efficiency (70 cd/A @ 1,000 cd/m²).

NEMO was a large €29 million project, co-funded by the German Federal Ministry of Education and Research (BMBF). The project's scope included emitter materials, charge transport materials and new adhesives for reliable encapsulation of each OLED component. The partners also performed physical tests on the materials and on the OLED components in order to gain more in-depth knowledge for future material developments.