Patterned polarization-rotating optical element and method of making the same, and 3D display

A patterned polarization-rotating optical element comprising a layer of birefringent material having a thickness d and a birefringence .DELTA.n,

• wherein the layer comprises at least one first region and at least one second region, at least one of the first and second regions comprising twisted birefringent material having a fixed twist angle .phi. such that .DELTA.n.multidot.d>>.phi..multidot..lambda./.pi., where .lambda. is a wavelength in vacuum of optical radiation, so that the at least one first region provides a first fixed angle of rotation of polarization of light and the at least one second region provides a second fixed angle of rotation of polarization of light, the second angle being different from the first fixed angle, and wherein the second fixed angle is substantially equal to zero degrees.

A method of making a patterned polarization-rotating optical element comprising the steps of:

• forming a layer of birefringent material having a thickness d and a birefringence .DELTA.n, the layer comprising at least one first region and at least one second region;
• and
• providing in the birefringent material of the at least one of the first and second regions a fixed twist angle .phi. such that .DELTA.n.multidot.d>>.phi..multidot..lambda./.pi., where .lambda. is a wavelength in vacuum of optical radiation, so that the at least one first region provides a first fixed angle of rotation of polarization of light and the at least one second region provides a second fixed angle of rotation of polarization of light, the second fixed angle being different from the first fixed angle.