Computer-aided deformable-mirror system using differential angle control.

The angles between neighboring small mirror elements are controlled by the signals from a microcomputer through properly arranged bimorph actuators so that an effective deformable mirror system is realized. This system has the following special features: (a) The surface of the mirror is continuous, and only the angles at the connecting edges between neighboring mirror segments are changed. This results in a smooth and largely deformable mirror surface with a smaller number of elemental mirrors than the conventional COAT system. (b) The errors in the mirror system, introduced in the fabrication of each mirror element and in the construction of the system, can be compensated by properly controlling the voltages supplied to the bimorphs. The information about these errors is obtained by previous measurements and stored in the computer. An experimental system was constructed, and some experimental results are shown. The results show the effectiveness of the method.