Method for operating a micromirror device with electromechanical pulse width modulation

A micromirror device comprising:

• at least one micromirror, each micromirror being configured to rotate along an axis parallel to the micromirror from a first position to a second position;
• a substrate underneath the micromirror;
• at least four controlling electrodes for each micromirror, the at least four controlling electrodes comprising a first and a second set, each set comprising two controlling electrodes, a first controlling electrode of each set being located on one side of the rotation axis of the micromirror and a second controlling electrode of each set being located on the other side of the rotation axis of the micromirror,
• wherein each electrode of the second set is connected to a circuit, the circuit being configured to keep, in use, a constant analog voltage signal during half of a time frame.

A system for operating a micromirror device, the micromirror device comprising at least one micromirror element being electrostatically deflectable around a rotation axis between at least two positions being a first position and a second position, the micromirror device further comprising a first and second electrode located on one side of the rotation axis and a third and fourth electrode on the other side, the system comprising:

• means for associating an intermediate value of intensity to the micromirror element during a time frame, the intensity being between a first value and a second value, the first value corresponding to the first position and the second value corresponding to the second position;
• and
• means for switching the micromirror element between the first position and the second position and vice-versa so that the micromirror element is either in the first position or in the second position, the intermediate value of intensity corresponding to a ratio of periods of time in the time frame in which the micromirror element is either in the first position or in the second position,
• wherein the switching is obtained by applying fixed voltage signals to the second and third electrodes during the time frame while applying periodic voltage signals having a period equal to the length of the time frame to the first and fourth electrodes, the fixed voltage signals being kept constant during half of the time frame.