Privacy-protection system using a unidirectional emission waveguide liquid crystal display and an asymmetrical transmission window system

Privacy-protection system using a unidirectional emission waveguide liquid crystal display (WG-LCD) with an electrically switchable vertically aligned polymer network LC (VA-PNLC) cell and an asymmetrical transmission window (ATW) system is reported. The configurations and operations of the WG-LCD, the WG-LCD with a VA-PNLC cell, the ATW system, and the privacy-protection system are elucidated. The ATW system comprises an absorption layer (dichroic dyes doped in two LC layers), a common window, and specific light sources. With the use of the privacy-protection system, people in a private space can see the private information displayed on the WG-LCD with the VA-PNLC cell and the scenes in a public space. Contrarily, people in a public space cannot see the scenes in the private space and the displayed information. The methods to increase optical performance of the privacy-protection system, WG-LCD with a VA-PNLC cell, as well as the method of designing the absorption layer with the light sources in a private space are elucidated. The ATW/privacy-protection system can be applied to various fields in daily life, such as car interior space and home/meeting room.