Privacy films are typically manufactured by combining black resin and transparent louver-shaped patterns. The use of black resin results in excellent light-shielding. However, black resin can reduce the transmittance of privacy films at the front viewing angle. In this study, we applied SiO₂/SiON multi-layer thin films on a privacy film to maintain transmittance at the front viewing angle and improve light-shielding at the side viewing angle. We determined the optimum combination of thicknesses of the SiO₂/SiON multi-layer stacks to increase the overall transmittance; the light shielding could be maximized at the side viewing angle.