Patent ID: 9335556
Filing Date: 2016-05-10
CPC Classification: G02B,G02F,G09G

Claim Text:
1. A backlight unit comprising: a waveguide assembly comprising a first wedge and a birefringent wedge disposed adjacent to, and arranged nose-to-tail with, the first wedge, to define an interface of the waveguide assembly, wherein: a liquid crystal layer extending along the waveguide assembly, the liquid crystal layer being configured to selectively switch the light between the first and second polarization states; and an extraction grating extending laterally along the waveguide assembly, the extraction grating being configured to extract the light from the waveguide assembly at an emission angle established in accordance with an angle of incidence of the light on the extraction grating, the angle of incidence being determined by an extent to which the light encountered the interface while propagating through the waveguide assembly in the second polarization state.