Crosstalk suppression in a directional backlight

摘要

Disclosed is a light guiding valve apparatus including a light valve, a two dimensional light emitting element array and an input side arranged to reduce light reflection for providing large area directional illumination from localized light emitting elements with low cross talk. A waveguide includes a stepped structure, in which the steps may include extraction features hidden to guided light propagating in a first forward direction. Returning light propagating in a second backward direction may be refracted or reflected by the features to provide discrete illumination beams exiting from the top surface of the waveguide. Stray light falling onto a light input side of the waveguide is at least partially absorbed.

主权项

1. A directional backlight for a transmissive spatial light modulator, comprising:
a waveguide having an input end, first and second, opposed guide surfaces for guiding light along the waveguide, and a reflective end facing the input end for reflecting light from the input light back through the waveguide; an array of light sources arranged to output light predominantly in an emission band and in a conversion band, the light sources being disposed at different input positions in a lateral direction across the input end of the waveguide, the waveguide being arranged to direct input light from light sources at the different input positions across the input end after reflection from the reflective end as output light through the first guide surface for supply through a transmissive spatial light modulator into respective optical windows in output directions distributed in the lateral direction in dependence on the input positions; and a reflection reduction element arranged to reduce reflections of light incident on the input end after reflection from the reflective end, wherein each of the light sources comprise a light generation element arranged to generate light in the emission band and a wavelength conversion material arranged to convert at least some of the light in the emission band generated by the light generation element into light in the conversion band.