Patent ID: 7058252

Claim:
A light direction switching apparatus for use in a directional display apparatus, comprising the following elements suitable for arrangement in series with a spatial light modulator: a switchable polariser being switchable between a first polarisation mode that passes light of a first polarisation component and a second polarisation mode that passes light of a second polarisation component; and an array of birefringent microlenses of a birefringence such that in operation the array of birefringent microlenses directs light of the first polarisation component substantially into a first directional distribution and light of the second polarisation component substantially into a second directional distribution different from the first directional distribution; the switchable polariser and the array of birefringent microlenses being positioned in series and arranged such that, when arranged in series with a spatial light modulator, light output by the light direction switching apparatus is substantially of the first polarisation component and is substantially directed into the first directional distribution when the switchable polariser is set to the first polarisation mode, whereas light output by the light direction switching apparatus is substantially of the second polarisation component and is substantially directed into the second directional distribution when the polariser is set to the second polarisation mode.