Polarized-light-emitting waveguide, illumination arrangement and display device comprising such
A side-lit illumination arrangement comprises a polarized-light-emitting waveguide comprising a polarization-selective beam-splitting interface formed at an interface of a waveguiding layer and a polarization-selection layer. In order to avoid alignment problems occurring during the manufacture of the waveguide which impair the proper functioning of the polarization-selective beam-splitting interface, the polarization-selective beam-splitting interface is planar. Waveguided light polarized and transmitted by the polarization-selective beam-splitting interface into the polarization-selection layer is coupled out by a relief-structured surface via an exit surface. Display devices having such waveguides, in particular if used in a front light, have a high brightness and efficiency.
1. A polarized-light-emitting waveguide comprising:
an entry side face via which, in operation, light from a light source arranged adjacent the entry side face enters the waveguide;
a waveguiding layer for waveguiding light entered via the entry side face;
an exit surface via which, in operation, polarized light exits the waveguide:
a polarization-selection layer provided adjacent to the waveguiding layer and, preferably, opposite the exit surface;
a planar polarization-selective beam-splitting interface formed at an interface of the waveguiding layer and the polarization-selection layer;
a relief-structured surface which is situated on the polarization-selection layer side of and is spatially separated from the polarization-selective beam-splitting interface, the relief-structured surface being adapted to redirect light polarized by the beam-splitting interface and incident on the relief-structured surface, via the exit surface, out of the waveguide; and
the waveguide comprises an outcoupling layer having a major surface in which the relief-structured surface is accommodated, the outcoupling layer being provided on the side of the polarization-selection layer facing away from the exit surface.
2. A waveguide as claimed in claim 1 wherein the outcoupling layer is optically isotropic.