| abstract |
The subject of the invention is an element having variable optical properties, comprising: n (a) a system having electrically controlled variable light scattering, of the optical-valve or liquid-crystal system type, a suspended-particle system or a holographic or thermotropic system (a′) which is associated with n (b) at least one absorbent element, absorbing at least in the visible range. n It applies especially to the manufacture of backprojection screens. |