A tiltable micromirror device is disclosed in which a micromirror is
suspended by a progressive linkage with an electrostatic actuator (e.g. a
vertical comb actuator or a capacitive plate electrostatic actuator)
being located beneath the micromirror. The progressive linkage includes a
pair of torsion springs which are connected together to operate similar
to a four-bar linkage with spring joints. The progressive linkage
provides a non-linear spring constant which can allow the micromirror to
be tilted at any angle within its range substantially free from any
electrostatic instability or hysteretic behavior.