Nikon Corporation

Tim Teng

Bausan Yuan

Kazuhiro Hirano

Pai-Hsueh Yang

Ping-Wei Chang

Pai Hsueh Yang

A stage assembly () for moving a device () includes a stage (), and actuator pair () and a control system (). The actuator pair () includes a first actuator () that is coupled to the stage (). The first actuator () has a first E core () and a first I core () that is spaced apart a first gap (g) from the first E core (). The control system () directs current to the first actuator () to move the stage (). In one embodiment, the amount of current directed to the first actuator () is determined utilizing a first parameter (a) that is added to the first gap (g). The value of the first parameter (a) is determined by experimental testing. Additionally, the amount of current directed to the first actuator () can be determined utilizing a second parameter (b) that is added to the first gap (g). The value of the second parameter (b) is determined by experimental testing.

E/I core actuator commutation formula and control method

A stage assembly () for moving a device () includes a stage (), an attraction-only type actuator pair () that moves the stage (), and a control system (). In one embodiment, the actuator pair () includes a first electromagnet (F), a first conductor (F) and a first target (F) having a first target surface (F). The actuator pair also includes a second electromagnet (S), a second conductor (S) and a second target (S) having a second target surface (S). The first electromagnet (F) is positioned at a first angle &#x3b8;relative to a first target surface (F) and the second electromagnet (S) is positioned at a second angle &#x3b8;relative to the second target surface (S). The control system () directs a first current to one or more of the electromagnets based on at least one of the angles &#x3b8;, &#x3b8;. Further, one or more electromagnets () can include a first measurement point and a second measurement point. The control system () can direct current to the actuator pair () based on the relative distance between the first and second measurement points and the corresponding target surface ().

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Fremont, CA, United States of America

Tim Teng