According to South Korean research firm UBI Research, color filters will replace polarizers in foldable OLED panels in the near future. This change will apparently make the display thinner and brighter. Major foldable OLED manufacturing companies are already working on the new display technology.
The currently available foldable OLED panels stack an encapsulation layer, polarizer, optically clear adhesive, and a cover window on top of the light-emitting layer. The cover window is made from either a polyimide film or ultra thin glass (UTG), depending on the manufacturer. Samsung uses UTG on the Galaxy Z Flip while the Motorola Razr employs a polyimide film.
Polarizers, meanwhile, are used in OLED panels to deflect reflections from external lights. Foldable OLED panels currently use polarizers that are about 10-micrometer thick. That's significantly thinner than the previous-generation ones that measured 100-micrometer in thickness.
However, they are still too thick for OLED panels and reportedly lower the brightness of the foldable display. To make foldable OLED panels brighter and thinner, companies are now looking to replace polarizers with color filters.
OLED firms are replacing polarizers with color filters in foldable OLED panels
Chinese display firm BOE had showcased a foldable OLED panel utilizing a lower temperature color filter instead of a polarizer back in 2017. At that time, the company said that the display was 100 times thinner. It also claimed the display to be about 23-percent brighter than OLED panels that utilized a polarizer.
The firm is apparently not yet ready to mass-produce the display. However, it should certainly be working on the next-gen display technology.
Samsung Display is also exploring this new technology. UBI Research believes the South Korean giant will commercially launch foldable OLED panels with color filters about three years down the line.
There are also a couple more methods to make foldable OLED panels thinner. Firstly, the current generation of foldable OLED panels stacks two layers of polyimide films at the bottom. OLED firms are attempting to reduce that to one layer.
However, displays with only one layer of polyimide film are difficult to handle. They may break during the laser cutting process.
Additionally, firms are also trying to reduce the thickness of the encapsulation layer. Currently, the inorganic materials that make the encapsulation layer are one micrometer thick.
But the organic ones range between 4-micrometer to 8-micrometer in thickness. Reducing the thickness of the organic materials may increase the signal-to-noise ratio of the touch sensor, though.
All major OLED firms are reportedly testing these two methods to make foldable OLED panels thinner. However, UBI Research is skeptical about them and believes replacing polarizers with color filters is the way forward for now.