Positioning device

A positioning device comprising:

• a base plate with a substantially flat surface;
• a movable carriage containing at least one gas bearing adapted for movement over said flat surface in at least two degrees of freedom;
• and
• a metrology component coupled to the carriage for determining a position of said carriage, said metrology component coupled to said carriage by a kinematic mount with exactly six simultaneous substantially independent constraints in six substantially independent directions,
• at least one load carrying member forming at least one constraint of said kinematic mount, said at least one load carrying member attached at one end to said at least one gas bearing and at another end to said metrology component, said at least one load carrying member having an axis comprising a substantially straight line between said at least one gas bearing and said metrology component.

A positioning device comprising:

• a base plate with a substantially flat surface;
• a movable carriage containing at least one gas bearing adapted for movement over said flat surface in at least two degrees of freedom;
• a metrology component coupled to the carriage for determining a position of said carriage, said metrology component coupled to said carriage by a kinematic mount with exactly six simultaneous substantially independent constraints in six substantially independent directions;
• and
• at least one actuator for moving said metrology component with respect to said at least one gas bearing, a first end of said at least one actuator being attached to said at least one gas bearing, and a second end of said actuator, movable with respect to said first end, being attached to said metrology component, said at least one actuator being at least one constraint of the kinematic mount.

A method of moving an object in a vacuum chamber comprising:

• placing said object on a movable carriage inside said vacuum chamber;
• moving said object in more than one degree of freedom on complimentary substantially flat gas bearing surfaces inside said vacuum chamber, said complimentary substantially flat gas bearing surfaces comprising at least one gas bearing comprising a static portion and a movable portion forming part of said movable carriage that allow relative motion with respect to one another, said at least one gas bearing being located entirely within said vacuum chamber,
• generating gas bearing forces by said at least one gas bearing that are perpendicular to a substantially flat surface of said static portion, all gas bearing forces produced by said at least one gas bearing that are substantially perpendicular to said substantially flat surface of said static portion acting on said movable portion in substantially the same direction, there being no gas bearings forming part of said movable carriage providing a force opposite to said forces in said substantially same direction;
• and
• generating magnetic forces by at least one magnet in said movable carriage creating a magnetic attraction between said static portion and said movable carriage a provide a force having a direction opposite to said gas bearing forces in said substantially same direction.