The global display cover market for foldable smartphones is increasingly being divided into transparent Colorless Polyimide (CPI) film and Ultra Thin Glass (UTG) due to the pros and cons of each solution, according to industry sources on Nov. 19.
Screen covers in smartphones serve to protect the displays, meaning they need to be resilient and flexible, all at the same time.
At the moment, CPI film appears to have the upper hand, especially as they can be mass-produced. Measuring at 220㎛ including layers of PET film and PSA, it’s also thinner than UTG cover windows with measurements of 250~270㎛.
This is why Samsung Electronics and Huawei both used CPI film for cover windows in their Galaxy Fold and Mate X foldable smartphones, and so did Motorola for its Razr phone.
However, a downside to CPI film is that creases appear when folded and it doesn’t offer the kind of clear visibility that glass does. CPI covers are also less scratch-resistant; as a preventative measure, Samsung added another hard-coating and a layer of special protective film manufactured by Se Gyung Hi Tech.
Meanwhile, the best feature of UTG is its hardness and visibility. It also offers a firm and solid aesthetic compared to the inevitably plastic look of CPI film. But UTG is far from being mass-produced, and it’s only half as bendable as CPI film.
Samsung had initially considered applying UTG to its second generation of the Galaxy Fold, but due to yield issues, it has confirmed UTG only for the clamshell type.
According to market research firm IHS Markit, CPI-applied smartphones will amount to around five times that of UTG in 2020, but the gap will narrow to 1.3-times by 2025. In terms of shipment, CPI is expected to peak in 2023, then fall. Reflecting the trends, Kolon Industries, which was the first in the country to mass-produce CPI film is likely to apply UTG to smaller displays, while keeping CPI for the bigger screens.
Along with Kolon Industries, Japan’s Sumitomo Chemical is another big player in the CPI film market. SKC and SKC Innovation, meanwhile, are also preparing to mass-produce the material soon.
For UTG, top companies are US-based Corning and Germany’s Schott. On the home turf, Dowoo Insys is a primary supplier, along with UTI Korea and Chemtronics, which are preparing to produce UTG for Samsung’s new generation of foldable phones.
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