Abstract: For producing the first differential of a two-dimensional optical image, an image of electrical charges corresponding to the brightness distribution of the image is produced in a first layer of an optical structural element. The first, electrical charges storing layer includes a plurality of light sensitive detector elements arranged in a mosaic-type pattern (D.sub.i). The electrical charge image representing the brightness distribution is converted into a transmissivity or transparency distribution corresponding to the potential differences across said detector elements in the first layer, by a second layer made of a material (M) that is electro-optically modulatable for changing the transparency or degree of transparency.

Abstract: The present remote data monitoring system employs a laser and a modulated retroreflector for the remote data monitoring of hard to access spaces, targets etc., in combination with an arrangement for a simultaneous friend-or-foe identification, and in combination with devices for the protection against detection and against interrogation of a friend by an enemy laser. In this system, a liquid crystal modulator of special construction depending on the purpose and structure of the system, is arranged in front of a retroreflector and modulated by the respective information. The information is interrogated by a spatially distant laser station by directing a laser beam onto the retromodulator, whereby the information is retroreflected and simultaneously modulated.

Abstract: A liquid crystal light modulator is constructed for the transmission of sch signals modulated onto a light carrier passing through gaseous, liquid, and solid media such as air, water, or glass. A large surface area modulation of the light is accomplished in the visible and infrared range over narrow, however adjustable, wave length ranges or widths. Several circuit arrangements for such modulators are disclosed and their function described.