Abstract: A continuously variable microdiaphragm has an aperture (3) which has a cross section and which has a shape which remains the same when the aperture becomes greater or smaller. The aperture is lozenge-shaped and is bounded by two recesses each disposed in a separable diaphragm strip (1a, 1b; 2a, 2b) Each of these strips is fixed on or forms part of a transmission leg (4, 5, 30, 31). These legs can be shifted symmetrically relative to each other.

Abstract: A device for focusing electromagnetic waves or sound, comprising a focusing element (1) fitted in a holder (2). This holder is supported in such a way that moving in three directions perpendicular to each other (X, Y and Z directions) is possible. Drive units (6, 26, 34) are used to move the holder independently in these three directions. To provide for very accurately controllable small movements of the holder in the X, Y and Z direction, the holder rests by means of hinges (7) on at least three legs (4) which at their bottom ends are connected by means of hinges (7) to a structure (5) which can be moved in the Z direction. The holder (2) for movement in the X and Y directions is hingedly connected by two perpendicular edges to a strip which can be moved to and fro by means of a drive element (26, 34).