E Ink has filed a patent for a flexible substrate that includes a plastic film with fillers and an overcoat layer made of various materials such as polyimide, acrylic resin, and epoxy resin. The substrate is designed to be flexible and can be used in various applications. GlobalData’s report on E Ink gives a 360-degree view of the company including its patenting strategy. Buy the report here.

According to GlobalData’s company profile on E Ink, E-transaction user interfaces was a key innovation area identified from patents. E Ink's grant share as of September 2023 was 54%. Grant share is based on the ratio of number of grants to total number of patents.

Flexible substrate with plastic film and overcoat layer

Source: United States Patent and Trademark Office (USPTO). Credit: E Ink Holdings Inc

A recently filed patent (Publication Number: US20230314950A1) describes a flexible substrate that can be used in various electronic devices. The substrate consists of a plastic film with fillers, which can be located within the main portion of the film or on its surface. The plastic film is covered by an overcoat layer made of materials such as polyimide, polybenzoxazole, benzocyclobutene, acrylic resin, epoxy resin, siloxane polymer, or novolak resin.

The overcoat layer may also include a color resist, which can be tan, burgundy, red, blue, green, white, or black. The thickness of the overcoat layer can range from 1 µm to 20 µm. It has desirable properties such as a low thermal expansion coefficient (CTE) of less than 60 ppm/°C, a high thermal decomposition temperature (Td) greater than 100°C, and a low dielectric constant of less than 5.

The overcoat layer also exhibits mechanical properties, including a Young's modulus greater than or equal to 1.5 Gpa, a tensile stress greater than or equal to 100 Mpa, and an elongation greater than or equal to 10%. The flexible substrate may also include a thin film transistor (TFT) array located on the overcoat layer.

The main portion of the plastic film can be made of materials such as polyimide, polyethylene naphthalate, polyethylene terephthalate, polymethyl methacrylate, polyether sulfone, or polyarylate. The fillers in the plastic film can be made of silicon nitride, silicon oxide, silicon oxynitride, or aluminum oxide.

The patent also describes a manufacturing method for the flexible substrate. The method involves placing the plastic film on a carrier and coating the overcoat layer on the film. The overcoat layer can be applied using techniques such as spin coating or slot-die coating. The carrier is then removed, leaving the flexible substrate.

Additional steps in the manufacturing process include spraying adhesive on either the carrier or the plastic film, baking the adhesive, detecting defects in the plastic film, and baking the overcoat layer. After detecting any defects, a thin film transistor array can be formed on the overcoat layer. Finally, the carrier is removed after the thin film transistor array is formed.

Overall, this patent describes a flexible substrate with specific material compositions and manufacturing methods that can be used in electronic devices. The substrate offers desirable properties such as flexibility, thermal stability, and mechanical strength, making it suitable for various applications in the electronics industry.

To know more about GlobalData’s detailed insights on E Ink, buy the report here.

Premium Insights


The gold standard of business intelligence.

Blending expert knowledge with cutting-edge technology, GlobalData’s unrivalled proprietary data will enable you to decode what’s happening in your market. You can make better informed decisions and gain a future-proof advantage over your competitors.


GlobalData, the leading provider of industry intelligence, provided the underlying data, research, and analysis used to produce this article.

GlobalData Patent Analytics tracks bibliographic data, legal events data, point in time patent ownerships, and backward and forward citations from global patenting offices. Textual analysis and official patent classifications are used to group patents into key thematic areas and link them to specific companies across the world’s largest industries.