Abstract: The flat panel display device is organized so as to have, on its front side, a part with dedicated liquid crystals used in back-up mode, a matrix display part with non-dedicated liquid crystals used in normal mode, and a keyboard where the meaning of its keys is displayed by the matrix. Furthermore, the non-dedicated liquid crystal matrix is addressed so as to increase operational safety and displaying speed.

Abstract: The display device of the invention includes several flat screens. Two sides of a case each form a flat screen display face controlled by the same control system. Under normal operation, the case is held in slides and only the screen disposed on one side is visible and in the emergency mode the case is pulled out of the slides and is pivoted so as to cause the other screen disposed on the othr side to appear.

Abstract: The device is designed to give a signal for the control of the ballast signal of a switched supply by using an index value signal. To benefit from the advantages of a digital control, the control signal is prepared as a function of logic values, pre-programmed in an encoding memory. The value of the index value signal at a given instant defines a starting and an ending of a zone in the encoding memory, and the cyclical reading of this zone through reading means gives the control signal.

Abstract: Several different symbols may be assigned to each key of the keyboard as requested by the operator. All the various symbols of the keys are recorded in a memory where they are organized in a certain number of pre-defined, distinct configurations of the keyboard. The configuration chosen by the operator is recorded in a display memory and displayed by means of a graphic unit on a flat panel, for example a liquid crystal display panel. The key actuated by the operator is identified by a decoding circuit to determine its symbol by means of the display memory and to display it on the flat panel.