Device for the local attenuation of the light intensity in the field of vision of a light-sensitive monitoring device

Abstract

A device for the local attenuation of the light intensity in the field of vision of a light-sensitive monitoring and/or recording device (CCD) is described, which is suitable in particular as a glare protection device for video cameras in videophones or correspondingly equipped PCs. The device includes a first objective (L1) and a high resolution ferroelectric liquid crystal modulator (PC, LC) arranged between two polarizers (P1, P2), the liquid crystal modulator having a photo-conductive layer (PC) and a downstream liquid crystal film (LC) made up of helical smectic liquid crystals which is in contact with this layer. The photo-conductive layer (PC) is essentially arranged in the image plane of the first objective (L1), the image plane being imaged onto the monitoring and/or recording device by a second objective (L2). As this occurs, bright light sources or backgrounds are locally suppressed without resulting in a glare or bloom of the image. As an alternative, if the intermediate imaging is omitted, the monitoring and/or recording device (CCD) may be arranged in the image plane of the first objective (L1), the second objective (L2) being eliminated. In this connection, the liquid crystal modulator (PC, LC) is arranged at close proximity to the monitoring and/or recording device (CCD) so that bright interference light sources are not only displayed as darkened but also blurred.

Dependencies are inferred from the claim text.