Patent ID: 7215475

Claim:
A lens array structure comprising a first birefringent lens array and a second birefringent lens array arranged in series, wherein both the first birefringent lens array and the second birefringent lens array are capable of operating to direct incident light of one polarisation into a respective directional distribution and to have substantially no effect on incident light of a polarisation perpendicular to said one polarisation, the first birefringent lens array and the second birefringent lens array are relatively oriented such that incident light of a first polarisation component is directed into a directional distribution by the first birefringent lens array and not affected by the second birefringent lens array whereas incident light of a second polarisation component polarised in a direction perpendicular to said first polarisation component is not affected by the first birefringent lens array and directed into a predetermined directional distribution by the second birefringent lens array, and at least one of the first birefringent lens array and the second birefringent lens array is an active lens array switchable between a first mode in which the active lens array directs incident light of one polarisation into a respective directional distribution and has substantially no effect on incident light of a polarisation perpendicular to said one polarisation and a second mode in which the active lens array has substantially no optical effect.