Highly transparent privacy filter film with image distortion

Abstract

We present a novel privacy filter film with transparent micro-cuboid arrays. The privacy filter film, which does not include any opaque materials, rarely affects the normal transparency, whereas it obscures personal information by distorting paths of oblique light rays. The effects of the cuboid size and a gap between the privacy filter and a display are analyzed using a ray-tracing program. The analysis is consistent with the experimental results carried out using the poly-dimethylsiloxane (PDMS) micro-cuboid (100 mu m x 100 mu m x 200 mu m) arrays, which are fabricated by lithography and transfer molding.