Optisches Element und seine Verwendung

摘要

Two polarisation conversion element arrays (320a) and (320b), each composed of a plurality of polarisation conversion elements for converting light incident thereupon to a linearly polarised light beam with a predetermined polarisation direction which are arranged in at least one of the array arrangement directions, either the direction of the lens array row or the direction of the lens array column, are disposed so as to oppose each other, with a predetermined space (Cp) provided therebetween at about the centre of the light-outgoing surface of a lens array (310) in the direction of arrangement. Of the light beams (s-polarised + p-polarised light beams) gathered by the lens array (310), light beam (L2) that is not incident upon the polarisation conversion element (320a) and passes through the predetermined space (Cp) is a light beam including a predetermined polarised light beam (s-polarised light beam) that is primarily made to leave the array (320a) and an ineffective polarised light beam (p-polarised light beam). Of the light passing through and leaving the space (Cp), the required polarised light beam alone can be made to leave as an effective light beam by providing a polarisation plate or the like at the light-outgoing side of the space (Cp).