Polarisation conversion system, optical lens array and projection display system

摘要

A polarisation conversion system has a polarisation splitting element (16) for directing light having a first polarisation in a first direction and for directing light having a second polarisation different from the first polarisation in a second direction different from the first direction; and one or more polarisation conversion elements (19a,19b) for converting light having the first and second polarisations to light having a substantially common output polarisation. The polarisation separation element comprises a first array of prisms (20) having a wedge-shaped cross-section, and a second array of prisms (21) also having a wedge-shaped cross section. One of the prism arrays is an array of birefringent prisms. The polarisation conversion system may be used in a projection display system. An optical element comprises a substrate having a first lens array 17 on one surface and a second lens array 18 on the other surface of the substrate.