PROCEDURE AND ELECTRONIC CIRCUIT FOR CONTROLLING LCD OPTICAL SWITCHING ELEMENTS

摘要

The application solves the problem of controlling LCD optic switching elements with alternating, rectangular electric signals with an amplitude that can change between several levels according to the current status. The changing of polarity of the control loops is supervised by an integrator, which integrates the voltage difference between the control electrodes of the LCD optical switching element in such a way that it retains the value of the time integral of the magnetic field within a predefined interval. Thus a complete elimination of long term direct current component of the electric control field for the LCD optical switching element is ensured regardless of the recurrence of changing or duration of individual electric control levels. Apart from that the electrical control signals in time are optionally provided with the possibility to equalise the potential on both electrodes at each modification of polarity of the electric control signals, which is far shorter than the LCD optic device switching time, thus allowing a spontaneous discharge of the electric capacity of the LCD optic switching element. By an appropriate selection of time it is possible to achieve an important reduction of power consumption required to control the LCD optic switching element.