| 摘要 |
The present invention relates to a polariser or a system for lighting using such a polariser in a polarisation recuperation system. The polariser comprises first and second polarising beam splitters ( 212 a, 212 b) for splitting first and second unpolarised beams each into at least first and second polarised beams of different polarisation states. The first and second polarised beams are guided to first and second light paths respectively. On these light paths, controllable polarisation conversion elements ( 218 a, 218 b) are positioned arranged such that the second polarised beam from the first unpolarised beam time-shares a same path through the polarisation conversion element ( 218 a, 218 b) as the first polarised beam from the second unpolarised beam. The controllable polarisation conversion elements ( 218 a, 218 b) are switchable to alternately convert the polarisation state or not convert the polarisation state, depending on which beam is switched to pass through the polarisation conversion elements ( 218 a, 218 b), corresponding with which of said first or second unpolarised beams are ON.
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