Patent ID: 7564509
Filing Date: 2009-07-21
Classification: G02B,G02F,H04N

Abstract:
1. Apparatus for controlling the illumination of an object, the apparatus comprising a first polarising beamsplitter separating incoming light into two linearly polarised components, a spatial light modulator (SLM) onto which the two linearly polarised components are directed and from which the light leaves along two beam pathways, and a second polarising beamsplitter onto which the two beam pathways are directed and from which light is directed to the object, the SLM having an array of elements each of which is switchable between a first state in which light of a first polarisation is directed into one of the beam pathways and light of a second polarisation is directed into the other of the beam pathways, and a second state in which light of the first polarisation is directed into the other beam pathway and light of a second polarisation is directed into the one beam pathway, the second beamsplitter being operative to combine the light of the first polarisation in the other beam pathway with the light of the second polarisation in the one beam pathway, enabling this combined light to be directed to the object.