Polarizer-free OLED - Page 2

Researchers from Dupont have developed a new OLED device architecture that has electrically polarized layers in the OLED stack. In this architecture, unlike previous polarized layers OLED devices attempts, there is less reduction in efficiency (caused by quenching of excitons).

The new architecture is based on molecules that form layers with substantial polarization. Using simulation methods, the researchers predicted the degree of polarization. By employing such materials in both the emissive layer and the adjacent electron-blocking layer, it was found that the device’s EQE is improved when the difference in polarization between the two layers is reduced. 

Last week, LG Display announced plans to invest $925 million to develop "advanced OLED technologies", saying that the funds will be invested over a period of 2 years (until June 30, 2027). The company did not share more information, but recent reports from Korea break down the project in more details.

So first of all, there are reports that LG Display will mostly focus on small and medium sized displays, for smartphones and IT devices. LG will also upgrade its WOLED production technology, for TV panels. Most of the funds will go into enabling LG to produce a higher percentage of high-end panels out of its OLED production lines.

China-based Tianma is showing many OLED displays and prototypes at SID Displayweek 2025. First up are two 13" concave displays (C-shaped and L-shaped), aimed for automotive dashboards. The company says that these distinctive contours not only deliver a striking visual experience but also helps enhance driver focus. Both displays are based on Tianma's tandem OLED architecture, which the company calls SLOD (Stacked Layer OLED Device, more on this below).

The second display is a 6.67" AMOLED that integrates a microLens array (MLA, which Tianma refers to as MLP or Micro Lens Pattern). Tianma says they adopt an innovative optical design to significantly boost the front-view light extraction efficiency. Tianma also shows a 6.78" tandem (SLOD) smartphone AMOLED display, to increase power efficiency. Tianma says that unlike traditional tandem OLEDs, its SLOD technology adopts a CGL structure with an extremely low device voltage using a differentiated light-emitting unit - thus achieving higher power efficiency. Tianma reports that the power consumption is reduced by 30% compared to a single-layer device, while brightness is increased by 25% and lifetime is up to four times higher.

Researchers from the University of Cambridge and the Eindhoven University of Technology developed a new OLED emitter that emits circularly polarised light. The researchers used molecular design tricks inspired by nature to create a chiral semiconductor by nudging stacks of semiconducting molecules to form ordered right-handed or left-handed spiral columns.

Chiral semiconductors could be very attractive as OLED emitters, as these could be more efficient as there's no need to add an external polarizer filter. The material used in this research is triazatruxene (TAT) that self-assembles into a helical stack. When excited by blue or ultraviolet light, TAT emits bright green light with strong circular polarisation.

Samsung Display unveiled a 18.1" rollable OLED laptop display at CES 2025, one that can roll down to 13.1" when closed. The company today announced that it aims to begin mass producing rollable OLED displays in April 2025. This will mark the first ever mass produced rollable display (apart for the limited volume production of LG's 65" rollable TV screens, that are discontinued).

During CES, Lenovo demonstrated the first laptop to use such a rollable OLED, the ThinkBook Plus G6 Rollable laptop. Lenovo plans to launch it globally in June 2025. The ThinkBook Plus G6 Rollable will have a 14" 5:4 display when rolled in, and a 16.7" 8:9 display when opened. That's an increase of almost 50% in screen size. The price of Lenovo rollable laptop will start at $3,499 - this is a ultra premium device.

Omdia has updated its Apple iPad and Macbook display roadmaps, with new forecasts and information about Apple's OLED adoption plans in its IT product lines. 

According to Omdia, Apple's iPad Mini will get a 8.4-inch LTPS OLED display in 2026. In 2027, Apple will also introduce OLED displays in its iPad Aid models (11-inch and 13-inch). In 2028 Apple will revamp the OLED displays in its iPad Pro models, offering a tandem architecture, polarizer-free OLED design and LTPO backplanes.

Omdia says that Color-Filter on Encapsulation (COE) will grow to be the dominant technology in foldable OLED smartphone panels, and will replace the currently-used circular polarizers. COE adoption will grow at a 33% CAGR between 2024-2030, and by 2030 almost 90% of foldable smartphones will use COE technology, and almost 20% of all smartphone OLED panels.

The adoption of COE in OLEDs increases the panel effective brightness, which means that the display consumes less power compared to a polarizer OLED (same brightness) and also lasts longer. The color gamut is also improved. On the other hand, COE OLEDs suffer from higher reflectivity compared to polarizer OLEDs. 

OLED displays have been gaining popularity rapidly, and are already the dominant smartphone display technology. OLEDs are also the display technology of choice in the smartwatch market, making inroads into the TV, monitor, laptop and tablet markets. The future of the OLED industry looks bright.

In recent years, the focus of the industry, beyond increasing capacity and reducing production costs, has been improving the performance of OLEDs in the areas of display brightness, efficiency, and lifetime. Brightness is required in many applications - from TVs (for HDR and to view in ambient lighting) through smartphones (outdoor viewing) to automotive, and efficiency is a plus in any scenario (but mostly in mobile displays). Display lifetime is already good enough for many applications, but in some cases (like automotive, and IT displays) it is critical. These three properties usually go together - if you can make more efficient OLED displays, you can drive them at a lower current to achieve the same brightness, and so lifetime increases, or you can achieve higher brightness, etc.