In the wake of rapidly increasing consumer demand for foldable OLED smartphones, color filter on encapsulation (COE) is forecast to grow at a high 33% compound annual growth rate between 2024–2030. The latest research from Omdia indicates COE will continuously displace circular polarizers as the method to reduce ambient light reflection and glare from OLED smartphones. By 2030, nearly 90% of foldable, and almost 20% of the nearly 1-billion-unit OLED smartphone market will adopt COE.
Although COE suffers from higher reflectivity than circular polarizers, it significantly increases panel brightness, which translates to reduced power consumption and increased lifetime. It also expands the color gamut. This is why some panel makers claim COE improves “readability”.
Additionally, being patterned directly on the panel, COE is thinner and reduces film stress compared to circular polarizing films laminated onto the display. These benefits make COE highly advantageous for foldable displays.
“The relatively high reflectivity of COE can be mitigated by utilizing a black pixel definition layer (PDL) as well as pixel, PDL, color filter (CF), and electrode design and process optimization. With multiple companies introducing new black PDL materials to the market, the trade-offs between circular polarizers and COE are diminishing, positioning COE as the preferred technology for foldable displays”, commented Charles Annis, Practice Leader in Omdia’s Display Research group.
COE requires considerable upfront capital outlays to purchase equipment and prepare facilities for coating and patterning the CF. Even so, Omdia cost modeling finds there is only a negligible difference in depreciated and mature manufacturing costs of OLED panels that apply COE compared to OLEDs with liquid crystal (LC) type circular polarizers.
High-end phones often use LC circular polarizers as they provide better performance than conventional film types.
“With minimal cost differences, the speed and extent to which COE will be adopted by conventional bar-type OLED-based smartphones will likely depend on consumer perceptions of its image quality advantages and disadvantages compared to circular polarizers,” added Annis.
