This application discloses a polarizer, comprising: a micro-lens array or micro-prism array as a means converting an incoming non-polarized light into a plurality of identical non-polarized light beams; a polarizing means dividing said plurality of non-polarized light beams into polarized transmitted and reflected light beams having different polarizations; a means for changing of the polarization and the direction of the light beams reflected from said polarizing means, thereby substantially converting light beams, re-reflected from said means for changing of the polarization, to same polarization and direction as light beams, transmitted through said polarizing means; said means for changing of the polarization and direction of the light beams comprises a sectioned mirror; said sectioned mirror is optically co-ordinated with said micro-lens array or micro-prism array. Also disclosed is a liquid-crystal display element, comprising a layer of liquid crystal disposed between a first and second plates, at least on one surface of which electrodes and at least one polarizer, as defined above, are disposed.