Patent attributes
A switchable privacy display comprises a spatial light modulator (SLM), a first switchable liquid crystal (LC) retarder and first passive retarder arranged between a first pair of polarisers and a second switchable LC retarder and second passive retarder arranged between a second pair of polarisers. Each switchable LC retarder comprises a homeotropic alignment layer and a homogeneous alignment layer. In privacy mode, on-axis light from the SLM is directed without loss, whereas off-axis light has reduced luminance to reduce the visibility of the display to off-axis snoopers. The display may achieve privacy operation in landscape and portrait orientations. Further, display reflectivity may be reduced for on-axis reflections of ambient light, while reflectivity may be increased for off-axis light to achieve increased visual security. In public mode, the liquid crystal retardance is adjusted so that off-axis luminance and reflectivity are unmodified. The display may be switched between day-time and night-time operation.
