COE to dominate as the main antireflection technology for foldable OLEDs

According to the latest research from Omdia, COE is expected to increasingly replace circular polarisers as the preferred method for reducing ambient light reflection and glare in OLED smartphones. By 2030, COE is anticipated to be used in nearly 90% of foldable devices and approximately 20% of the broader OLED smartphone market, which is projected to reach nearly 1 billion units.

Despite COE's higher reflectivity compared to circular polarisers, it offers several significant advantages that make it an attractive option for smartphone manufacturers. Notably, COE enhances panel brightness, leading to reduced power consumption and extended device lifespan. Additionally, COE improves the colour gamut, which some panel makers argue enhances screen readability.

One of the key benefits of COE is its application directly onto the panel, resulting in a thinner design and reduced film stress compared to the traditional method of laminating circular polarising films onto the display. These characteristics make COE particularly beneficial for foldable displays, where thickness and flexibility are critical factors.

Charles Annis, Practice Leader in Omdia’s Display Research group, commented on the emerging trend: “The relatively high reflectivity of COE can be mitigated by utilising a black pixel definition layer (PDL) as well as optimising the design and process of the pixel, PDL, colour filter (CF), and electrode. With several companies introducing new black PDL materials, the performance gap between circular polarisers and COE is narrowing, making COE increasingly appealing for foldable displays.”

However, the adoption of COE technology does require significant initial investment, as manufacturers must purchase specialised equipment and prepare facilities for the coating and patterning of the colour filter. Despite these upfront costs, Omdia’s cost modelling indicates that the difference in mature manufacturing costs between OLED panels using COE and those with liquid crystal (LC) circular polarisers is minimal.

High-end smartphones often utilise LC circular polarisers due to their superior performance over conventional film types.

Annis further explained:“With minimal cost differences, the rate at which COE will be adopted by traditional bar-type OLED smartphones will largely depend on consumer perceptions of its image quality relative to circular polarisers.”

As the competition between COE and circular polarisers intensifies, the future of OLED smartphone displays will likely hinge on both technological advancements and consumer preferences.