Displacement devices, moveable stages for displacement devices and methods for fabrication, use and control of same

Patent metadata

Field	Value
Publication number	US-10958148-B2
Application number	US-202016888586-A
Country	US
Kind code	B2
Filing date	May 29, 2020
Priority date	Jun 14, 2014
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

A displacement device includes a stator having non-parallel stator-x and stator-y elongated traces. The device also includes a moveable stage having a first magnet array with first magnetization segments linearly elongated in a stage-x direction and having magnetization directions generally orthogonal to the stage-x direction. The first magnet array includes a first pair of adjacent first magnetization segments made up of two first magnetization segments adjacent to one another in a stage-y direction non-parallel to the stage-x direction. Each first magnetization segment in the first pair has a corresponding magnetization direction oriented at a corresponding angle αn about a corresponding stage-x axis as measured from a positive stage-z direction that is generally orthogonal to both the stator-x and stator-y directions. The corresponding angle αn is one of 45°+n90° where n is any integer. Each first magnetization segment in the first pair has a different magnetization direction.

First claim

What is claimed is:

1. A displacement device for moving a moveable stage relative to a stator, the displacement device comprising:
a stator comprising:
an x-trace layer comprising a plurality of electrically conductive x-traces which extend generally linearly in a stator-x direction across an excitation region;
a y-trace layer comprising a plurality of electrically conductive y-traces which extend generally linearly in a stator-y direction across the excitation region;
the x-trace layer and the y-trace layer overlapping one another in a stator-z direction over the excitation region;
the stator-x direction and the stator-y direction non-parallel to one another and the stator-z direction generally orthogonal to both the stator-x and stator-y directions;

a moveable stage comprising:
a first magnet array comprising a plurality of first magnetization segments linearly elongated in a stage-x direction, each first magnetization segment having a corresponding magnetization direction;
wherein the first magnet array comprises one or more first pairs of adjacent first magnetization segments, each first pair of adjacent first magnetization segments comprising two first magnetization segments adjacent to one another in a stage-y direction;
wherein, for each first pair of adjacent first magnetization segments:
each first magnetization segment in the first pair has a corresponding magnetization direction that is oriented in a direction other than the stage-x direction, the stage-y direction or a stage-z direction where the stage-x direction, the stage-y and the stage-z direction are each orthogonal to one another; and
each first magnetization segment in the first pair has a different magnetization direction; and

a controller connected to one or more amplifiers, the controller and the one or more amplifiers configured to drive currents in at least one of the x-traces and the y-traces to move the moveable stage relative to the stator.

2. A displacement device according to claim 1 wherein the moveable stage comprises:
a second magnet array comprising a plurality of second magnetization segments linearly elongated in the stage-y direction, each second magnetization segment having a corresponding magnetization direction;
wherein the second magnet array comprises one or more second pairs of adjacent second magnetization segments, each second pair of adjacent second magnetization segments comprising two second magnetization segments adjacent to one another in the stage-x direction and wherein, for each second pair of adjacent second magnetization segments:
each second magnetization segment in the second pair has a corresponding magnetization direction that is oriented in a direction other than the stage-x direction, the stage-y direction or the stage-z direction; and
each second magnetization segment in the second pair has a different magnetization direction.

3. A displacement device according to claim 2 wherein the magnetization direction of each first magnetization segment is generally orthogonal to the stage-x direction and the magnetization direction of each second magnetization segment is generally orthogonal to the stage-y direction.

4. A displacement device according to claim 2 wherein:
for at least one of the one or more first pairs of adjacent first magnetization segments, the two first magnetization segments of the first pair have corresponding magnetization directions which are generally orthogonal to one another; and
for at least one of the one or more second pair of adjacent second magnetization segments, the two second magnetization segments of the second pair have corresponding magnetization directions which are generally orthogonal to one another.

5. A displacement device according to claim 2 wherein:
the corresponding magnetization direction of each of the plurality of first magnetization segments is oriented at a corresponding angle α n about a corresponding stage-x axis aligned with the stage-x direction as measured from a positive stage-z direction and wherein the corresponding angle α n is one of 45°+n90° where n is any integer;
the corresponding magnetization direction of each of the plurality of second magnetization segments is oriented at a corresponding angle α m about a corresponding stage-y axis aligned with the stage-y direction as measured from the positive stage-z direction and wherein the corresponding angle α m is one of 45°+m90° where m is any integer; and
wherein the first magnet array comprises four or more of the plurality of first magnetization segments and the second magnet array comprises four or more of the plurality of second magnetization segments.

6. A displacement device according to claim 2 wherein:
the first magnet array further comprises one or more axial first magnetization segments, each axial first magnetization segment having a corresponding magnetization direction generally orthogonal to the stage-x direction and oriented in one of: a positive stage-y direction; a negative stage-y direction; a positive stage-z direction; and a negative stage-z direction; and
the second magnet array further comprises one or more axial second magnetization segments, each axial second magnetization segment having a corresponding magnetization direction generally orthogonal to the stage-y direction and oriented in one of: a positive stage-x direction; a negative stage-x direction; the positive stage-z direction; and the negative stage-z direction.

7. A displacement device according to claim 2 wherein:
the plurality of first magnetization segments comprises a number N tx =4 different corresponding magnetization directions; and
the plurality of second magnetization segments comprises a number N ty =4 different corresponding magnetization directions.

8. A displacement device according to claim 2 wherein:
the first magnet array comprises a pair of first sub-arrays separated from one another in the stage-y direction by a non-magnetic gap; and

the second magnet array comprises a pair of second sub-arrays separated from one another in the stage-x direction by a non-magnetic gap.

9. A displacement device according to claim 8 wherein:
each of the first sub-arrays comprises a corresponding sub-array plurality of first magnetization segments and each sub-array plurality of first magnetization segments has features of the plurality of first magnetization segments; and
each of the second sub-arrays comprises a corresponding sub-array plurality of second magnetization segments and each sub-array plurality of second magnetization segments has features of the plurality of second magnetization segments.

10. A displacement device according to claim 2 wherein:
a width W my of the first magnet array in the stage-y direction is given by W my =nλ 1 /4 where n is a positive integer and λ 1 is a first spatial period;
a width W mx of the second magnet array in the stage-x direction is given by W mx =mλ 2 /4 where m is a positive integer and λ 2 is a second spatial period.

11. A displacement device according to claim 10 wherein:
the first spatial period λ 1 is a spatial period associated with a variation of the magnetization directions of the plurality of first magnetization segments across the stage-y direction of the first magnet array; and
the second spatial period λ 2 is a spatial period associated with a variation of the magnetization directions of the plurality of second magnetization segments across the stage-x direction of the second magnet array.

12. A displacement device according to claim 10 wherein:
the first spatial period λ 1 is a spatial period of a first Halbach array having a plurality of first Halbac

Assignees

• Univ British Columbia

Inventors

• Lu Xiaodong

Classifications

• H02K2213/03

  Machines characterised by numerical values, ranges, mathematical expressions or similar information · CPC title

• H02K41/031 Primary

  of the permanent magnet type · CPC title

• H02P25/066

  of the stepping type · CPC title

• H02K2201/18

  Machines moving with multiple degrees of freedom · CPC title

• H02P25/064

  of the synchronous type · CPC title