Technical integration of 6-inch flexible AMOLED display module and PEDOT touch panel

- Dec 26, 2018-

The 6-inch flexible PEDOT touch panel fabricated on PI (polyimide) film requires an etch-free process and "Multipurpose Flexible Electronic Substrate Technology" (FlexUpTM). In the flexibility test, the resistance change (ΔR/R0) of the PEDOT electrode decreased by 1% after the 10K winding test. With the help of video switching system, picture exchange system and zoom in/out function, the technical integration of 6-inch PEDOT touch panel and AMOLED display module has been successfully demonstrated.

Transparent doped metal oxides such as ITO (Indium Tin Oxide) have been the main choice for applications such as liquid crystal displays, touch panels, OLEDs (organic light-emitting diodes), and solar cells. However, the metal oxide film is extremely poor in flexibility and usually produces cracks 1 during bending or twisting. Therefore, a variety of flexible electrode materials have been considered as an alternative to ITO, such as PEDOT: PSS polymer 2, carbon nanotubes 3, graphene 4, and nanosilver wires 5. Compared with other alternative materials, the liquid conductive polymer PEDOT, which is currently widely concerned with 6-8, has a variety of core competitive advantages, including lower haze, more affordable, and can be combined with gravure and squeezing extrusion. The coating is compatible with solution deposition techniques such as slit coating. This article will examine in detail the use of highly conductive PEDOT as a transparent electrode in flexible touch panel applications, including optical performance, reliability, and flexibility testing. In addition, the results of the integration of PEDOT touch panels and AMOLED display module technology will also be verified.

  Production Process

The highly conductive PEDOT product formulation (produced by Taiwan EOC Co., Ltd.) mentioned herein is used as a transparent conductor. Figure 1 (a) and (b) show top and cross-sectional views of the PEDOT touch panel structure. FlexUPTM substrates are produced by applying a polyimide varnish over a single release layer. Subsequently, a transition layer is deposited on the substrate by a vacuum deposition process. Silver plays a role as a bridge through the mapping process. Thereafter, the isolation layer generates a dielectric layer by a deposition and pressing process. After the conductive polymer is introduced through the spin coating process, the visual drawing process 9 is used for pressing, and the final step of the touch sensor manufacturing process is completed. At this point, the touch sensor can be detached by mechanical debonding technology.