Positioning device, stiffness reduction device and electron beam apparatus

A positioning device configured to displace an object, comprising:

• a stage to support the object,
• an actuator to move the stage with respect to a reference in a direction of movement,
• a balance mass arranged between the actuator and the reference to reduce transfer of reaction forces from the actuator to the reference,
• a support device arranged between the reference and the balance mass to support the balance mass, and
• a gravity compensator acting between the reference and the balance mass to exert a lifting force on the balance mass to reduce a gravitational support force to be provided by the support device to support the balance mass,
• wherein the gravity compensator is arranged to exert an attracting force on the balance mass or wherein the gravity compensator is arranged to exert a repelling force on the balance mass.