Polarizer-free OLED

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. 

Recently, BOE, Tianma, TCL, EDO and Visionox all posted their financial results for Q2 2024, and all were rather positive. Samsung Display and LG Display also posted increased earnings for the quarter.

So we start with BOE, that posted revenues of 93.4 billion yuan (13.17 billion USD) for the first half of 2024, an increase of 16.47% over H1 2023. Its net profit increased 210% compared to last year (2.285 billion Yuan, or $320 million USD). BOE enjoyed increased LCD sales and optimized production, and also noted high demand for high-end foldable OLED displays.

During iMID 2024, Samsung Display's eVP Yi Chung said that the company plans to reduce the power consumption of its OLED panels by over 50%. SDC is developing several technologies, each contributing to the same efficiency goal.

SDC did not detail its plans exactly, but it did mention some of the new technologies it is working on - polarizer-free OLEDs (these have been commercialized already), multi-frequency driving (demonstrated by other OLED makers), tandem OLED architecture and the adoption of high efficiency blue PHOLED emitters.

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. 

TCL CSOT demonstrated its latest displays, technologies and prototypes at Display Week 2024. The company is focused on inkjet printing technologies, and a lot of the displays on show were indeed printed.

So first up, we TCL demonstrated a 14" 2880x1800 400 nits 30-120Hz ink-jet printed LTPO AMOLED display. The display is produced on a glass substrate, with thin film encapsulation (a 'hybrid OLED').

Samsung Display announced its latest OLED panel, the Eco²OLED, which increase light output by 33% compared to SDC's previous OLED panels. The increase light translates into a power consumption reduction of up to 25%.

For the Eco²OLED panel, Samsung finally managed to commercialize a polarizer-free OLED, after many years of R&D. The first phone to adopt this display will be Samsung's upcoming Galaxy Fold 3. Interestingly Samsung says that the new design also enabled it to incorporate a high-quality under-the-display camera as more light is entered through the OLED.

BOE demonstrates several new OLED technologies at SID Displayweek 2021. First up is a new rollable display. The new display is 8-inch in size, and it features a resolution of 2592x2176 and a bending radius of 4 mm. BOE says the new display passed over 200,000 sliding cycles.

Last year at Displayweek 2020, BOE demonstrated a 12-inch rollable OLED. It has since been working with LG Electronics on the company's rollable smartphone (which was since canceled as LG withdrew from the smartphone market) and with OPPO on a 7.4-inch sliding OLED phone.

In March 2021 Tianma unveiled a new OLED display technology, which it refers to as CFOT OLED - a polarizer-free OLED that adopts color-filters instead to remove reflections. The company demonstrated a 8.03" CFOT OLED prototype at SID Displayweek 2021:

Tianma says that a CFOT OLED enables a thinner design, improves the light emittance and also cuts the power consumption by 20%. The 8.03" display offers a resolution of 2000x2544 (403 PPI).

Samsung Display has been developing polarizer-free AMOLED displays for many years, and last year UBI detailed how the company plans to use color filters to eliminate the need for polarizers and so increase the efficiency of their OLED panels while also lowering the thickness.

DSCC posted an interested article that details Samsung's upcoming polarizer-free OLEDs, which it brands as POL-LESS OLEDs. The first OLEDs to adopt this new structure are expected to be adopted in Samsung's Galaxy Fold 3 later this year.

UBI Research reports that OLED makers are aiming to adopt color filters instead of polarizers in foldable OLED displays. The polarizer help prevent internal reflections by external light, but they lower the brightness and limit the flexibility of the panel.

Using color filters instead of the polarizer may enable brighter panels and also thinner ones which are more flexible. BOE has already demonstrated such a panel back in 2017 (scheme shown above) - and they said it is 23% brighter than a polarizer OLED, and it is also 110 um thinner. Samsung Display is also developing similar technology.