Patent ID: 8854603

Claim:
A weight force compensator configured to mount an optical element and to compensate for a force F which acts in a direction z and which is applied to a force application point in a microlithographic projection exposure apparatus, the weight force compensator comprising: an armature of a compensation element, the armature being movable in the direction z of the force F and encompassing the force application point, the compensation element having a first force-distance characteristic curve in the direction z of the force F, a first bearing stiffness S 1 of the compensation element being given by a quotient of a difference ΔFF 1 between a maximum and a minimum force of a first force interval ΔF 1 comprising the force F and an absolute value of a first distance interval Δz 1 around a first point z 0 , the absolute value of the first distance interval Δz 1 being assigned to the first force interval ΔF 1 by way of the first force-distance characteristic curve, and the force F being assigned to the first point z 0 by way of the first force-distance characteristic curve; and a guide mechanism having a second force-distance characteristic curve in the direction of the force F to guide the armature of the compensation element, the guide mechanism having a second bearing stiffness S 2 given by a quotient of a difference ΔFF 2 between a maximum and a minimum force of a second force interval ΔF 2 and the absolute value of the first distance interval Δz 1 , the second force interval ΔF 2 being assigned by the second force-distance characteristic curve by the first distance interval Δz 1 around the first point z 0 , wherein: the force of the force compensator results from an addition of forces from the first and second force-distance characteristic curves; a force-distance characteristic curve resulting from the addition of forces has a third bearing stiffness S 3 , which is a quotient of a difference ΔFF 3 between a maximum and a minimum force of a third force interval ΔF 3 comprising the force F and the absolute value of the first distance interval Δz 1 around a point z 0 *; the third force interval ΔF 3 is defined by the resulting force-distance characteristic curve by a first distance interval Δz 1 around the point z 0 *; the point z 0 * is assigned to the force F by way of the resulting force-distance characteristic curve; and at least one of the following holds: the bearing stiffness S 3 is less than or equal to the bearing stiffness S 1 ; the resulting force-distance characteristic curve has at least two points z 0 * which are spaced apart from one another by more than the first distance interval Δz 1 ; and in the resulting force-distance characteristic curve, the difference ΔFF 1 around the force F is assigned to a distance interval greater than Δz 1 .