The invention relates to a shutter for an optical imaging system. An
amount of opaque fluid is moved in a planar capillary space to open and
close the shutter. Depending on the position of the opaque fluid with
respect to an optical path passing through the capillary space, the fluid
opens or blocks the optical path. In an embodiment, the opaque fluid is
moved by a pressure differential caused by a diaphragm which is coupled
to a piezoelectric actuator. In another embodiment, the opaque fluid is
moved by electrostatic forces.