High Light-fast Indium Tin Oxide FIlm
Transparent Conductive Film Resistant to UV Rays
- What is ITO film?
- In this film, ITO—indium tin oxide, whose main raw material is the rare metal In (indium)—is deposited on a film. ITO has the distinguishing feature of being highly transparent and electrically conductive, and is used in the electrodes for displays and similar devices. However, since it is metal, special technology is needed to deposit it on a thin, flexible film.
- Development of film materials using core technologies
- Gunze is working to develop products that make use of the functional thin film formation technologies for film surfaces (sputtering, wet coating) that we have cultivated for optical applications. In films used as a transparent, conductive material, ITO is deposited onto a film surface with a thickness of a few tens of nanometers, but if this technique is used alone, the patterning of the ITO film ends up being visible (Fig. 1). This is a fatal issue for displays and other optical applications, and it is essential to ensure this patterning cannot be seen. In addition, ITO film has a tendency to degrade when exposed to sunlight for a long time, and this was previously an issue for use in automobiles and outdoors. Using our original optical design technology, we at Gunze improved this problem, and thus were able to develop and offer transparent conductive film that is resistant to UV rays.
Resistant to degradation due to UV rays!
ITO film has outstanding light-fastness, and is suitable for automotive and outdoor applications. The whitening phenomenon, which occurs due to long-term exposure to sunlight, has been improved (see Fig. 2).
- Crystallization of metal film
- Crystallization of the metal film is essential for ITO film. Ordinarily, commercial ITO films are sold while still uncrystallized, and annealing treatment is performed on the buyer side. At Gunze, we perform crystallization with our in-house annealing equipment, and thereby provide ITO film with a stabilized resistance value.
High-sensitivity, low-resistance ITO film!
To realize larger screens for applications such as displays, it is necessary to reduce the resistance of transparent conductive film. However, lowering resistance makes it even more difficult to provide the invisible characteristic. Gunze is working to lower resistance while improving this problem and maintaining high visibility, and our aim is to produce high-sensitivity ITO films suitable for large-sized applications.
*The above are actual measured values, not guaranteed values.