Vibration damping devices and methods
First Claim
1. An apparatus, comprising:
- a first electrode attached to a first surface of a supporting member;
a second electrode attached to a second surface of a vibrating member, said first electrode and said second electrode defining a gap therebetween;
a displacement sensor that outputs a signal indicative of a change in said width of said gap caused by vibrations of said vibrating member; and
a controller connected to the first electrode, the second electrode and the displacement sensor, the controller configured to receive said signal from said displacement sensor and to apply an electrical force between said first electrode and said second electrode according to said signal so as to damp said vibrations.
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Accused Products
Abstract
Vibration of a member supported by another member is damped by detecting the changes in the width of a gap between the members and applying an electrical force between the members in a time-dependent manner. The detection of the changes in the width of the gap may be carried out by an optical displacement sensor or by a capacitive displacement sensor. The electrical force is applied by attaching electrodes on mutually opposite surfaces of the members and connecting them to a voltage source such that their voltages can be varied or to a current source such that mutually parallel and/or antiparallel currents can flow through them. Vibration damping devices structured for using such a vibration damping method can provide shock-absorbing mounts to apparatus of different kinds such as lithography exposure apparatus having an optical frame supported by a base frame, a workpiece being placed on the base frame and the optical frame supporting an optical system for irradiating the workpiece with radiative energy.
21 Citations
22 Claims
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1. An apparatus, comprising:
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a first electrode attached to a first surface of a supporting member;
a second electrode attached to a second surface of a vibrating member, said first electrode and said second electrode defining a gap therebetween;
a displacement sensor that outputs a signal indicative of a change in said width of said gap caused by vibrations of said vibrating member; and
a controller connected to the first electrode, the second electrode and the displacement sensor, the controller configured to receive said signal from said displacement sensor and to apply an electrical force between said first electrode and said second electrode according to said signal so as to damp said vibrations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of damping vibrations of a vibrating member supported by a supporting member, said supporting member having a first surface, said vibrating member having a second surface, said method comprising the steps of:
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attaching a first electrode on said first surface of said supporting member;
attaching a second electrode on said second surface of said vibrating member, said first electrode and said second electrode defining a gap therebetween with a specified width;
generating a signal indicative of a change in said width of said gap caused by a vibration of said vibrating member; and
applying an electrical force between said first electrode and said second electrode according to said signal so as to damp said vibration. - View Dependent Claims (10, 11, 12, 13)
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14. A lithography exposure apparatus comprising:
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a base frame supporting a workpiece, said base frame including a first member having a first facing surface;
an optical frame supporting an optical device that irradiates said workpiece with radiative energy, said optical frame including a second member supported by said first member, said second member having a second;
a first electrode attached to said first surface of said first member;
a second electrode attached to said second surface of said second member, said first electrode and said second electrode defining a gap therebetween;
a displacement sensor that outputs a signal indicative of a change in said width of said gap caused by vibrations of said second member with respect to said first member; and
a controller connected to the first electrode, the second electrode, and the displacement sensor, the controller receiving said signal from said displacement sensor and applying an electrical force between said first electrode and said second electrode according to said signal so as to dampen said vibrations. - View Dependent Claims (15, 16, 17, 18)
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19. An apparatus comprising:
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a wafer table having a first electrode;
a mirror assembly affixed to the wafer table, the mirror assembly having a second electrode, the first electrode and the second electrode defining a gap between the mirror assembly and the wafer table;
a displacement sensor that generates an output signal indicative of a change in the width of the gap caused by vibrations between the wafer table and the mirror assembly; and
a controller connected to the first and second electrodes and the displacement sensor, the controller configured to receive the output signal from the displacement sensor and to apply an electrical force between the first electrode and the second electrode according to the output signal. - View Dependent Claims (20, 21, 22)
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Specification