Ambient contrast ratio (A-CR) is a critically important characteristic for mobile displays. For transmissive and emissive displays (such as liquid crystal display, light-emitting diode, and organic light-emitting diode), A-CR decreases dramatically as the ambient light increases, which degrades the image quality, especially for outdoor applications. Moth-eye-like structure greatly reduces the surface reflection and improves A-CR. For a touch panel display, the surface should be robust enough to resist possible mechanical scratches and to self-clean possible contaminations from fingerprints and dusts.
In this paper, we demonstrate the moth-eye-like structure fabricated on a hard-coating layer with additional surface treatment for self-cleaning property upon the flexible film. By laminating the film unto a display device, the luminous reflectance is reduced to ~0.23%, which improves the A-CR by ~4X under the sun. Note that although the surface reflection is reduced, the haze remains negligible, implying that the image quality is not blurred. The nanostructure was fabricated on the hard-coating layer which is typically used as the protective film of the mobile display and hence it is anti-scratched. Typically, nanostructure exhibits hydrophobic and olephobic properties. With suitable surface treatment by amphiphilic molecules, such characteristics are further improved with excellent self-cleaning properties. Besides, our nanostructured hard-coating film can be fabricated on different flexible films, such as TAC and PET, which means this broadband antireflection film can be used for flexible displays.