tandem architecture - Page 6

Taiwan's National Tsing-Hua University (NTHU) Professor Jou and Dr. Wen have been developing OLED lighting technologies for many years, focusing on healthy bluelight-free OLEDs (so-called candle-light OLEDs) due to the hazards of modern lighting.

The researchers now report they have developed a new tandem-OLED device that improves the efficiency and lifetime of their candle-light OLEDs. The OLED's emission is totally blue-light free, which makes it even safer compared to NTHU's first-gen candle-light OLEDs.

OLED microdisplay developer Seeya Information Technology was established in 2016, and in 2017 it started building a $300 million OLED 300 mm microdisplay production line. Seeya's fab is now in operation, with a yearly capacity of around 20 million displays (monthly capacity of 9,000 300 mm wafers).

Seeya quickly became a prominent display maker, who's currently producing high performance displays to global customers. The company says it's currently the world's largest OLED microdisplay maker by volume. Seeya's current standard displays include:

Researchers from Kyushu University reported that they have developed a promising new blue OLED emitter system, based on a two-unit stacked tandem hyperfluorescence OLED with improved singlet-excited-state energy transfer from a sky-blue assistant hetero-donor-type TADF (HDT-1) dopant.

The research reports that the new emitter system offers a pure-blue color (CIE 0.13, 0.16), a narrow spectrum (full-width at half-maximum of 19 nm), an EQE of 32% at 1,000 cd/m² and a lifetime of 18 hours LT95. The lifetime is still lacking, but with stricter control of device fabrication and procedures the researchers say they expect that device lifetimes will further improve to rival commercial fluorescent blue OLEDs.

Last month we posted that the Korean Elec publication claims that Apple is aiming to adopt OLEDs in its next iPad Pro devices - and as Apple wants extended lifetime from these panels, the Korean panel makers are developing tandem OLED devices (easier for LG as it is already producing such panels for automotive applications).

Today another Korean publication, ETNews, has posted that Apple is aiming to start using OLEDs in its iPads in 2022. According to ETNews, Apple indeed reached out to both LG Display and Samsung Display for these OLEDs.

In a very interesting post, The Elec states that Apple has reached out to both Samsung Display and LG Display, requesting that the display suppliers develop a longer-lifetime OLED display for Apple's next iPad Pro devices.

LG 12.8-inch P-OLED in Mercedes Benz 2021 S-Class

The lifetime of the current crop of mobile OLED devices is not enough for Apple's iPad - which is designed to be used for a longer period of time compared to a smartphone. An increased lifetime will also result in lower burn-in problems which seem to trouble Apple.

Kopin Corporation announced in January 2020 that the company developed a new double-stack OLED architecture that enables brighter microdisplays with longer lifetime. Earlier Kopin announced a new 1.3" 2560x2560 OLED microdisplay, developed with Panasonic and Lakeside Optoelectronic, that uses the new double-stack architecture and achieves brightness of over 1,000 nits.

Kopin 1" 2k x 2k OLED Lightning microdisplay

Kopin now announced that they have achieved a breakthrough color fidelity (> 115% sRGB) for its latest 1.3" 2.6K x 2.6K OLED display. Kopin believes that this is the world’s highest color fidelity achieved on dual-stack OLED microdisplays - equal to that on the best single-stack OLED microdisplays.

First-O-Lite (FOL) was established in 2010 in Nanjing, China with an aim to become an OLED lighting developer and producer. Based on its hybrid tandem architecture, FOL has a 2-Gen OLED lighting production fab that is currently producing 70 lm/W OLED lighting panels.

This article details the company's OLED lighting panels, its strategy to create an initial health-lighting niche market in china, its current product families and its technology and business roadmaps going forward.

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.

Report from Japan say that Sharp developed a new 3.4" bendable OLED prototype. The AMOLED display features a resolution of 540x960 (326 PPI), it has an aperture ratio of 57% and a thickness of 70um. The bending radius is 10mm, and the whole panel weighs 2 grams. The backplane is IGZO.

While this is reported as news, this panel seems to be quite similar to OLEDs Sharp unveiled at SID 2012 (yes, almost four years ago!). According to the reports, Sharp says that the display has a long lifetime and is "color shift free", as a result of newly developed tandem structure.

UBI Research estimates that the OLED lighting market will take off in 2015, and will grow to reach $4.7 billion in revenue by 2020. According to UBI within three years a 100x100 mm OLED lighting panel will cost under $5 to produce. This is assuming a large substrate (1270x1270 mm), a fast production process and a tandem structure.

In such a scenario, the largest cost (over 80%) will be for the OLED materials. This means that at that stage companies will put most of their focus on lowering the material usage and cheaper OLED materials.