between large size and the large angle of rotation is resolved by dividing the required area of the mirror into a plurality of small elongated mirror elements each of which is sufficiently narrow to allow the required rotation fig4 is a top view of a portion of a micro machined mirror assembly 30 and fig5 is a cross sectional view through line 38 39 shown in fig4 mirror assembly 30 is constructed from a plurality of micro machined mirrors 32 that have been etched from a substrate 35 that is bonded to a second substrate 37 each mirror is connected to substrate 35 via a flexible link 31 that allows the mirror to rotate about an axis through the flexible link the force needed to rotate each mirror element is generated by an electrostatic actuator 33 which consists of two conductive electrodes facing each other the actuation potential is applied to the appropriate actuator either from an off chip source or with the aid of control circuitry 36 that is embedded in the silicon substrate 37 on which the mirror assembly is mounted the top surfaces of the mirrors are covered with a highly reflective coating typically a film of gold about 0 2 micron thick the angular rotation of the mirror about the flexure point is determined by the potential applied to the actuator for a given actuation voltage v the spacing d is approximately related to the half width w by the following equation where k is the dielectric constant k 0 is the permittivity.