Abstract: When an ideal voltage reference is assumed such that the central value of the data voltage envelope is constant, the selection voltages include various successive portions which have a duration longer than a time control window, substantially correspond to a single polarity, have an average voltage in the range of 0.95 times Vs+ to 0,95 times Vs−, where Vs+ and Vs− are the positive and negative peak values in the selection voltage assembly. Said assembly has overlapping selection times and is such that all positive voltages higher than 0.9 Vs+ are included in a first time interval set and all negative voltages higher than 0.9 Vs− are included in a second time interval set, the voltages of said first set being interlaced with the voltages of said second set, with intervals of both sets within each time control window substantially corresponding to the two polarities of the selection voltage associated with the concerned window.

Abstract: When an ideal voltage reference is assumed such that the central value of the data voltage envelope is constant, the selection voltages include various successive portions which have a duration longer than a time control window, substantially correspond to a single polarity, have an average voltage in the range of 0.95 times Vs+ to 0.95 times Vs−, where Vs+ and Vs− are the positive and negative peak values in the selection voltage assembly. Said assembly has overlapping selection times and is such that all positive voltages higher than 0.9 Vs+ are included in a first time interval set and all negative voltages higher than 0.9 Vs− are included in a second time interval set, the voltages of said first set being interlaced with the voltages of said second set, with intervals of both sets within each time control window substantially corresponding to the two polarities of the selection voltage associated with the concerned window.

Abstract: Subject-matter of this invention is a control method for a ferroelectric liquid crystal matrix panel wherein use is made of selection voltages comprising, at each selection operation, at least two (write) pulses, that is voltages having substantially an identical polarity in finite time intervals, of the same polarity, spaced apart by an interruption wherein voltages of opposite polarity are present, as well specified. The absolute value of the time integral of the voltage during the second pulse (write post-pulse) is in the range of 0.2 Amin to 5 Amin. The control time window associated to the selection voltage includes time intervals wherein voltages of opposite polarity are applied in the interruption, comprehensively extending for at least one and no more than four fifths of the duration of said window, and the absolute value of the integral of the selection voltage in the assembly of said time intervals is in the range between 0.05 Amin and 1 Amin.

Abstract: Subject-matter of this invention is a control method for a ferroelectric liquid crystal matrix display panel wherein use is made of selection voltages comprising at least four impulses, more particularly voltages having substantially an identical polarity in finite time intervals, at each refresh step of the panel, the last two pulses being consecutive and having opposite polarities, having absolute values of the voltage integral with respect to time within well established limits during each pulse and wherein use is also made of well specified control time windows. Regarding the last pulse, said absolute value of the voltage integral with respect to time is in the range of 0.2 Amin to Amin; regarding the last-but-one pulse, it is in the range of 0.2 Amin to 3 Amin; regarding a (compensation) pulse prior to the two above pulses, it is in the range of 0.8 Amin to 3 Amin and, regarding a (blanking) pulse prior to the above three pulses, it is in the range of 1 to 10 times the value of the compensation pulse.

Abstract: A method is disclosed for the manufacture of cells having a hollow space adapted to lodge a liquid crystal, such cells being used, for example, in various display devices. The essence of the method is to induce in the supporting members forming the walls of the cell an elastic deformation and to maintain the confronting cell surfaces pressed together with the interposition of appropriate spreaders. Such elastic deformation is originated by imparting an appropriate curvature to at least one of the supporting members prior to uniting them and welding them together. Critical values for the radius of curvature are given, as well as for the spreader interspaces.

Abstract: An operational method is disclosed for the display of images by an electro-optical device comprising a liquid-crystal cell inserted between two polarizing devices, means being provided for impressing on the liquid crystal electric pulses, the improved method comprising the step of applying a pulsed energization, each pulse being any voltage waveform having a duration and an RMS amplitude such as to originate, at each pulse, a cell luminous response and not exceeding 1.3 times those which are required to produce a flash of light with a peak amplitude which cannot be further increased without causing more than one peak to appear. In the case of repetitive energization, the pulse repetition period, under steady conditions, shall be such that at the end of the period, the luminous response of the cell falls irreversibly to a value which is not more than one half of that peak value corresponding to "white level".