An optical control device includes a drive member formed with a plurality of reflecting regions along a second track and movable along the second track for driving a driven member to move along a first track. At least one of the valve ports 19C, 19D is biased toward a rotation center of the valve body 20 against the center of the corresponding pipe fitting 15, 16. A feedback control circuit modulates the effective turns-ratio of a variable dc-dc transformer to regulate the output voltage. Further, for the precoding element of the precoding vector a phase angle is selected which corresponds to a calculated interference strength indicator fulfilling a predefined interference strength criterion. The film is attached to the frame due to the suction effect exerted by vacuum openings configured on the frame, thereby fixating the film on the gripper.