Abstract: A dimming device, with a brightness dimming ratio of 1 to 1000, for a fluorescent lamp used for the backlighting of a liquid crystal screen comprises a periodic signal generator for delivering rectangular pulses with an adjustable duty cycle. The pulses are synchronized with the image synchronizing signal of the liquid crystal screen. An alternating voltage generator provides power to the lamp only during the pulses. The decrease in tube efficiency for very short pulses allows the required dimming intensity to be achieved without image flickering.

Abstract: A display system with a matrix type flat panel, for example a liquid crystal panel, has addressing circuits to obtain a television type interlaced image. These circuits are divided into several blocks, both for the addressing of even-numbered and odd-numbered columns and for the addressing of even-numbered and odd-numbered lines, in order to obtain a high-definition image. The graphic processor means used to prepare the video signals to be displayed comprise two sub-groups, one for each of the odd or even image. The two subgroups are respectively associated with two different data measuring devices giving the same essential information, to allow at least one display to be maintained even if one device malfunctions, each of them having at least one symbol generator associated with an image memory to produce a protected display of essential data for use.

Abstract: The invention relates to a graphic display device. The main object of the invention is a screen display device using a combination of directed-beam scanning for drawings of patterns and frame-scanning display for surface coloring. The device of the invention comprises a microprocessor which makes real-time calculations, for each line displayed, of the starting and finishing abscissae of the various colors to be used. Real-time computing by the microprocessor makes it possible to use video memories instead of the habitually used page memories and to replace a very bulky and expensive graphic processor with a fast microporocessor. The invention can be applied chiefly to the display of three-dimensional perspective views on color screens.