Partial gating image intensifier based on liquid crystalauto-controlling light intensity

摘要

In order to enlarge the dynamic range of image intensifier, and CCD can work normally under the strong light (10~5lx),based on the generation II image intensifier, we have brought forward an novel equipment of double lens optical systemincluding a liquid crystal panel (twisted nematic liquid crystal panel LCX023-CMT) and a photometric CCD whichdetects the illuminance real-time. The light intensity is controlled by liquid crystal automatically and the partial gatingcan be realized. The principle of auto-controlling light intensity is introduced detailedly in this paper. And thetransmittance of liquid crystal has been simulated. Experimental result displays that the optical transmittance changedfrom 1.28% to 25.60% with the gray levels from 0 to 250. The high linearity relation of transmittance to gray levels isobtained when the gray levels change from 90 to 220. The feasibility of partial light intensity auto-controlled by liquidcrystal has been further proved by the two obvious contrast pictures that one is photographed with the liquid crystalpanel and another without.