| 摘要 |
<p>1521724 Modulating light THOMSON-CSF 5 Sept 1975 [6 Sept 1974] 36751/75 Heading G2F [Also in Division H4] A device for projecting colour images transmitted over a distance by a video signal, comprises a display cell 2 including a layer 25 of liquid crystal material in a smectic phase, an infrared laser 10 for providing a recording spot, said recording spot scanning layer 25 for producing at its point of impact a transitory conversion of said material from said smectic phase to the isotropicphase, a light source 30 for directing a parallel beam 3 of white light on to cell 2, a control element 4 for receiving said video signal, supplying synchronization pulses to laser 10, and applying three chrominance signals to a pair of electrodes 23, 24 sandwiching layer 25, three chrominance images being thereby recorded in cell 2 in the form of local variations in the scattering effect of layer 25 and providing from beam 3, three beams 3R, 3V, 3B, the three beams being filtered for selecting in each beam a respective spectral band and combined into a single beam by means of four dichroic mirrors 32-35, and a screen 5 for receiving colour images. In a modification, the chrominance signals are applied to a modulator 15 to modulate the intensity of the beam from laser 10, electrodes 23, 24 being discarded. In a further embodiment, Fig. 4 (not shown), three display cells are used, each cell recording one of the three trichromic components of the image to be reproduced, the three images being recorded simultaneously. When the chrominance signals are applied to electrodes of the display cells, the images recorded therein may be erased by an erasing pulse supplied by the control device. If successive images are transmitted one after the other, the erasing pulse may be controlled by the image synchronizing pulse. The three cells may be illuminated by three flashlights which are turned on simultaneously also by the image synchronizing pulses. The screen 5 may be replaced by a trichromatic photo-sensitive emulsion.</p> |
