Touch panels, which are operated by touching the screen with a finger or a pen, are used in a wide range of fields, including office and factory automation, game consoles, personal digital assistants (PDAs) and ATMs. Within a few years, the market for touch panels is expected to grow by around 30 percent. This market alone consumes 2.5 million square meters of transparent electroconductive film, with Teijin Chemicals' ELECLEAR accounting for approximately 24% share.

A transparent electroconductive film is thin, light, resilient and flexible, making it superior to glass in many ways. Utilizing such advantages, the film is used as major transparent electrodes of resistive touch panels. Generally, resistive touch panels are composed of two conductive-coated substrates separated by a narrow gap. When an object, such as a pen, presses down on a point on the panel's outer surface, both substrates come into contact with each other, and then the subsequent voltage change triggers the data transmission. ELECLEAR also is used mainly for a resistive touch panel, commanding majority market shares for game consoles, smartphones and PDAs.

Superior visibility, anti-smudging and durability

ELECLEAR is composed of hard coating, undercoating and indium tin oxide (ITO) layers on top of a polymer-film substrate. The hard-coating and undercoating layers incorporate proprietary coating technology to prevent glare and rainbow patterns caused by film deflection and flicker, as well as offering strong resistance to finger smudging. ELECLEAR also is highly durable — in a test, its ITO layer remained unaffected after 10,000 finger taps, while conventional films deteriorated after 5,000 taps.

PC and PET substrate materials: Teijin's diversity

One of the Teijin Group's strengths in a field of transparent electroconductive film is that it produces substrates with two different types of materials — polyethylene terephthalate (PET) film manufactured by Teijin DuPont Films and polycarbonate (PC) film manufactured by Teijin Chemicals. Teijin also has the facilities and expertise to produce both films from raw materials.

Teijin Chemicals is the only company in the world to produce a transparent and electroconductive PC film. PC and PET films are applicable to not only resistive but also capacitive touch panels, which detect differences between the electrostatic capacitance of a fingertip and conductive film to identify touch position. Both touch panels are used in growing markets for devices such as ATMs and ticket vending machines. Besides producing a wide variety of touch panels, Teijin Chemicals also is the industry's top supplier, having expanded capacity of ELECLEAR to 1.2 million square meters in 2008.

Transparent electrodes and much more

The demand for transparent electroconductive film for touch panels in smartphones and other devices is growing. In addition, it is anticipated that the film will be applied to further products, such as electronic papers, which have highly promising applications in electronic books, organic EL lightings, and photovoltaic cells. Teijin Chemicals continues to further improve performance of ELECLEAR and expand uses in promising markets.

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