July 4, 2017: Sunlight readability is a critical requirement for display devices, especially for mobile displays. Anti-reflection (AR) films can greatly improve sunlight readability by reducing the surface reflection. An international team of researchers has, therefore, found that use of moth-eye-like nanostructure like antireflection surface can enhance any display readability under the bright sun.
The researchers of Shin-Tson Wu, College of Optics and Photonics, University of Central Florida have developed a model to simulate and optimize the optical behaviours of micro-dimples as seen on a moth’s eyes (optimized to catch all available light at night and reduce glare).
In a paper titled ‘Broadband antireflection film with moth-eye-like structure for flexible display applications’ published in the Optica journal, the researchers has discovered a flexible substrate nano-imprinted with dimples about 100 nanometres in diameter, layered with a thin hard-coating film. Self-assembled nanospheres are used to create the imprint master, a fabrication process that is easily scalable to large film sizes, the researchers said. The expect the new flexible AR film will make it to the smartphone market.
A flexible anti-reflection (AR) film with a luminous reflectance under 0.23% and exhibiting less than 1% haze is the result. That is how an order of magnitude lower than the iPhone’s surface reflection measured at 4.4 percent and turns any display panel (rigid or fixed) into a sunlight readable unit.
This efficient AR film would remove the need for adaptive brightness control, which brightens the display’s output under bright light but also drains battery power.
The film would have good mechanical characteristics (pencil hardness over 3H), which will make it suitable for touch panels, as it is flexible to a bending radius of 8mm. The researchers made the film waterproof with a fluoroalkyl coating to raise hydrophobicity. With a water contact angle over 100°, water-based liquids just slides off the screen and help keep it clean.