[Display Dynamics] High Hopes for Colorless Polyimide

Publication date: 13 Jun 2019 Author: Irene Heo Senior Principal Analyst, Display Materials & Components

[Display Dynamics] High hopes for colorless polyimide

Brought to you by Informa Tech [Display Dynamics] High hopes for colorless 1 polyimide Table of Figures: michellewhitcombihsmarkitcom_2019_6_13_11_48_59_capturepng1 ...... 3 michellewhitcombihsmarkitcom_2019_6_13_12_43_40_capturepng2 ...... 3

Key findings . The era of flexible displays has dawned. With Royole’s FlexPai and Samsung Electronics’ Fold, the industry will be seeing a continuous flow of flexible products. . Due to the structural characteristic of being able to fold and open multiple times, plastic covers are used instead of glass. CPI film, a transparent film type of PI (Polyimide) is widely used as an alternative to glass. . Kolon Industries is a market leader, seeking to expand the use of CPI film from cover film to touch/barrier film, and even panel substrates.

The era of flexible displays has dawned upon us. Royole Corporation of China introduced its smartphone FlexPai, the industry’s first bendable smartphone, and Samsung Electronics, albeit unsuccessful, released its version under the name Galaxy Fold. Following suit, Huawei is also planning to launch its foldable smartphone, Mate X. The trend is spreading fast among makers, and it is expected that the market will be able to see not only foldable smartphones but also foldable notebooks next year. In fact, Lenovo is preparing a product that is applied with a 13.3-inch OLED panel, which can be used as a tablet when completely spread open, and a mini notebook when folded. All such products are still in their early stages, but it is promising that they have the benefit of a changeful form factor, and they have already built a segment in the industry under foldable. Because of the structural characteristics where the screen must endure multiple folding and spreading, the existing glass cover was switched to a plastic cover, and in other words, the application of a plastic cover has heralded the opening of the foldable market. Currently, colorless polyimide (CPI) is the only plastic cover that is durable and mass produced. Previously, materials such as PMMA (Poly methyl methacrylate) or PC (Poly carbonate) had been applied on feature phones, but they were not meant to be folded, just merely for flat displays. Due to the inherent traits of plastic, it is difficult to restore the material back to its original state when folded multiple times, and the folded areas become opaquely white when a plastic is crystalized by the stress of folding, which is why it is difficult to apply it as a foldable display. Of course, CPI film covers still have to be further developed in terms of durability. In order to be applied as a cover, a certain level of hardness must be achieved, and since the user has to touch the screen continuously, the pressure must not affect the panel components. For this, specific processes have been added, such as a surface treatment like hard coating, as well as an additional functional layer to absorb external shocks. The defect that was reported about the Galaxy Fold recently, is also attributed to the contamination of the protective film and hinge area, put in place to enhance the durability of the plastic cover. It is evident that securing durability and reliability is a must for plastic covers. There are suggestions for alternatives of CPI film, such as Ultra-Thin Glass, but knowing that this will be vulnerable to external shocks, it will require additional treatment to compensate for its weakness. The current market leader of CPI film is Kolon Industries. It is the only company that operates a Gen 6 mass production line. Kolon’s CPI film is adopted on Royole’s FlexPai, and although Lenovo has not disclosed all

the component SCMs for the foldable notebook slated for release next year, there is a good chance that Kolon’s CPI will be applied on the cover lens. As a virtuous cycle, such manufacturing experiences will be conducive to Kolon to swiftly come up with solutions for any drawbacks it has with the product. Meanwhile, Kolon Industries introduced a film type CPI-F and varnish type CPI-V at SID 2019. The diagram below shows “Current target application of Kolon”. michellewhitcombihsmarkitcom_2019_6_13_11_48_59_capturepng1

As for mass production, it only offers CPI-F for cover windows, but this type is expected to be expanded in use to touch sensor substrate. (refer to the diagram below) The target structure is similar to an add-on touch sensor for AMOLED; but using the same PI materials for all substrates, the OLED module can avoid heterogeneity. Since this touch substrate will be formed from varnish type material, the touch sensor can be transferred to all desirable layers from the cover window to under the polarizer. Kolon is currently in talks with touch materials suppliers, to apply CPI as a touch sensor material film. michellewhitcombihsmarkitcom_2019_6_13_12_43_40_capturepng2

While the varnish type CPI-V has not been applied on actual products, there is a good chance that it can be applied for TFT substrates in foldable displays. Generally, CPI material tends to show lower thermal

resistance than normal PI materials. But, CPI-V products have high thermal resistance, being able to endure high temperatures of 350 degrees. This makes it suitable for the TFT process, which requires a considerable amount of heat. Additionally, as the full-screen display becomes a big trend in the smartphone market, bezel, home button, camera lens, and speaker are allowed to have the minimum space, so some set makers are applying notch or hole for these functions. It is difficult for camera lens to be removed from the screen, but if transparent panel using CPI as the substrate are used, the camera module can be placed behind the panel, and we can have the real full-screen display.

Download [Display Dynamics] High hopes for colorless polyimide - 355.88kb | pdf

Citation policy Request external citation and usage of Omdia research and data via [email protected]. Omdia consulting We hope that this analysis will help you make informed and imaginative business decisions. If you have further requirements, Omdia’s consulting team may be able to help you. For more information about Omdia’s consulting capabilities, please contact us directly at [email protected]. Copyright notice and disclaimer The Omdia research, data and information referenced herein (the “Omdia Materials”) are the copyrighted property of Informa Tech and its subsidiaries or affiliates (together “Informa Tech”) and represent data, research, opinions or viewpoints published by Informa Tech, and are not representations of fact. The Omdia Materials reflect information and opinions from the original publication date and not from the date of this document. The information and opinions expressed in the Omdia Materials are subject to change without notice and Informa Tech does not have any duty or responsibility to update the Omdia Materials or this publication as a result. Omdia Materials are delivered on an “as-is” and “as-available” basis. No representation or warranty, express or implied, is made as to the fairness, accuracy, completeness or correctness of the information, opinions and conclusions contained in Omdia Materials. To the maximum extent permitted by law, Informa Tech and its affiliates, officers, directors, employees and agents, disclaim any liability (including, without limitation, any liability arising from fault or negligence) as to the accuracy or completeness or use of the Omdia Materials. Informa Tech will not, under any circumstance whatsoever, be liable for any trading, investment, commercial or other decisions based on or made in reliance of the Omdia Materials.