Directional display apparatus

Abstract

A switchable privacy display comprises at least one light source, a structured birefringent component, an out-of-plane polariser, a polarisation switch, and an in-plane polariser. The polarisation switch is arranged between the out-of-plane polariser and the in-plane polariser, and the polarisation switch is also arranged between the structured birefringent component and the in-plane polariser. The display device is arranged to output an image formed using light which has been output from the at least one light source and which has passed through the structured birefringent component, the out-of-plane polariser, the polarisation switch and the in-plane polariser. The display can operate in a privacy mode of operation that provides a high security factor in non-viewing directions and high image visibility in viewing directions, or in a wide-angle mode of operation that provides high image visibility for a relatively wider field of view.

Dependencies are inferred from the claim text.