The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 21, 2003
Filed:
Apr. 06, 1999
Wolfgang Dultz, Frankfurt/M, DE;
Leonid Beresnev, Darmstadt, DE;
Deutsche Telekom AG, Bonn, DE;
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 (L ) and a high resolution ferroelectric liquid crystal modulator (PC, LC) arranged between two polarizers (P , P ), 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 (L ), the image plane being imaged onto the monitoring and/or recording device by a second objective (L ). 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 (L ), the second objective (L ) 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.