Roll-to-Roll ITO Film for Touch Panel Application: Durable ITO Sputter Deposition and Hard Coat Wet Coating

摘要

It is said that about 5 million square meters of transparent conductive films are used in the world market. Almost 80 percent of them are used to touchscreen. Four types of touchscreen exist, which are resistive type, optical type, supersonic wave type and electrostatic type. The resistive type is composed of upper electrode and lower electrode. These electrodes are made from transparent electro-conductive membrane (see Figure 1).When we push the touchscreen with a finger or a pen, the upper and lower electrode are touched together and indicate the pushing position. There are glass/glass, film/glass and film/film electrode consists in resistive type touchscreen usage. Writing durability and hitting durability (contact durability of an electrode side) are required as for plastic-film type transparent conductive film touchscreen.Touchscreen have been started with glass and glass electrode consist, then plastic-film type are increased because of their light touch force, light weight and prevention of broken glass hurting. Plasticfilm type electrodes are poor heat resistance and scratch resistance compare with glass, because it is difficult to deposit the indium tin oxide (ITO), and crystallize at high temperature like as glass. It was said that if ITO layer on a plasticfilm base are crystallized, reliability should be improved exceedingly.Oike succeeded to realize crystallized ITO in the touchscreen market as a transparent conductive film. This report shows our feature and technology development of the Dry-coating and the Wet-coating for which the transparent conductive performances as touchscreen required.