- Problems with sensor electrode materials in electrostatic capacity-type touch panels used in smartphones resulted in difficulties responding to increasing trends for three-dimensional curves, flexibility, and larger screens on displays.

- Tanaka Kikinzoku Kogyo constructed a system for manufacturing an almost invisible ultrafine wire metal mesh (MM) sensor film at a low cost, utilizing roll-to-roll process printing using silver nano ink.

- This means that touch panel functions can be added evenly to bendable displays and can be used in OLED displays. It is also anticipated that films with antibacterial, catalyst and thermal insulation functions will come into use.

TOKYO - (ACN Newswire) - JST (President, Michinari Hamaguchi) has recognized the results of NexTEP's project, "A Sensor Film for Touch Panels*1 Using Thin Metallic Wire" as a success.

This development task was based on the research of Professor Tatsuo Hasegawa, Principal Research Manager at the Flexible Electronics Research Center of the National Institute of Advanced Industrial Science and Technology, and was consigned to Tanaka Kikinzoku Kogyo (Representative Director & CEO, Akira Tanae, Chiyoda-ku, Tokyo) from April 2014 through September 2017. The research proceeded with the aim of practical application through Tanaka Kikinzoku Kogyo's Global Marketing/R&D Division.

In conventional electrostatic capacity-type touch panels*2, indium tin oxide (ITO) is used for the sensor. However, because of its high electrical resistivity and weakness upon bending, companies faced difficulties in increasing the size of such sensors and making them more flexible. Metal mesh*3 (MM) solves these problems, but it is difficult to make thinner than 4 um, and no technology existed to manufacture the mesh via printing.

To apply the new technology (SuPR-NaP method*4), which fabricates wiring through an adsorption reaction between special silver ink and an activated fluororesin surface, at a suitable speed for commercial manufacturing, the project clarified the reaction mechanism and researched the development of manufacturing equipment as well as the conditions for each process. As a result, the project constructed a system for manufacturing MM film (line width: 2-4 um) with the full process roll-to-roll method*5. In a 200,000-frequency (radius: 2 mm) bending test, this MM film exhibits hardly any changes in resistance values, and it has cleared general reliability testing.

This success in manufacturing the world's first micro-wiring film with a full process roll-to-roll method is an important technological innovation in printed electronics for the flexible electronic device market. It is also anticipated that the technology could be applied and used for applications requiring metal patterns on resin film (function films e.g. antibacterial, catalyst, thermal insulating).

Context

With the increased use of information technology in society, people are demanding access to information in various locations, at various times and in various situations. Touch panels that are integrated with the display are used in many devices, from smartphones, notebooks, large panel to automotive displays.

To continue, please go to http://www.acnnewswire.com/press-release/english/40806/