Positioning arm for and method of placing a scan head on a support surface

Patent metadata

Field	Value
Publication number	US-10488433-B2
Application number	US-201615743762-A
Country	US
Kind code	B2
Filing date	Jul 14, 2016
Priority date	Jul 15, 2015
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

The invention is directed at a positioning arm for positioning of a scan head of a surface scanning measurement device—such as a scanning probe microscopy device—relative to a surface. The positioning arm comprises a base at a first end thereof for mounting the arm with the base to a static reference structure. The positioning arm further comprises a first and a second arm member extending from the base, the second arm member extending parallel to the first arm member. The arm comprises a bridge member at a second end thereof, connecting the first and the second arm members. The first and the second arm member are respectively connected to each one of said base and said bridge member by means of a hingeable connection. The positioning arm further comprises an actuator for inducing a relative displacement between the first and the second arm member in a longitudinal direction of said first and second arm member for swinging the second end of the positioning arm in a direction transverse to the lateral displacement. The bridge member comprises a support for supporting the scan head.

First claim

The invention claimed is:

1. A positioning arm for positioning of a scan head of a scanning probe microscopy device relative to a surface, wherein the positioning arm comprises a base at a first end thereof for mounting the arm with the base to a static reference structure, wherein the positioning arm further comprises a first and a second arm member extending from the base, the second arm member extending parallel to the first arm member, wherein the positioning arm comprises a bridge member at a second end thereof, the bridge member connecting the first and the second arm members at said second end of the positioning arm, wherein each one of the first and the second arm members is respectively connected to each one of said base and said bridge member by means of a hingeable connection, and wherein the positioning arm further comprises an actuator acting on the first and second arm members to enable a relative displacement between the first and the second arm members in a longitudinal direction of said first and second arm members for swinging the second end of the positioning arm in a lateral direction that is transverse to the relative displacement, wherein the bridge member comprises a support for supporting the scan head.

2. The positioning arm according to claim 1 , further comprising a controller cooperating with the actuator for controlling operation thereof for controlling the relative displacement between the first and the second arm members.

3. The positioning arm according to claim 2 , wherein the controller is arranged for obtaining an amount of said relative displacement between the first and second arm members, and wherein the controller is arranged for calculating a transverse displacement of the bridge in a direction transverse to the positioning arm based on the amount of relative displacement.

4. The positioning arm according claim 2 , further comprising a sensor unit for measuring the relative displacement between the first and the second arm members and for providing a sensor signal indicative of said relative displacement to the controller.

5. The positioning arm according to claim 4 , wherein the sensor unit comprises at least one element of a group comprising an optical distance sensor, such as an interferometer, an electrical proximity sensor, such as a capacitive sensor or inductive sensor.

6. The positioning arm according to claim 1 , wherein the actuator is arranged between the first arm member and the second arm member, and wherein the actuator comprises a first actuator part fixedly mounted to either one of the first or second arm member, and wherein the actuator comprises at least one second actuator part that is movable relative to the first actuator part by means of operation of the actuator in use, wherein the second actuator part acts upon said second arm member for inducing said relative displacement between the first and second arm members.

7. The positioning arm according to claim 6 , wherein the actuator comprises a large stroke actuator element and a small stroke actuator element, wherein the large stroke actuator element comprises a spindle, wherein the spindle is comprised by the second actuator part and cooperates with the first actuator part to be movable relative thereto, and wherein the second actuator part further comprises a piezo type actuator mounted on a tip of said spindle and forming the small stroke actuator.

8. The positioning arm according to claim 1 , wherein the actuator comprises one or more of: a large stroke actuator element for enabling large stroke longitudinal displacements between the first and second arm members, such as a spindle type actuator, or a small stroke actuator element for enabling small stroke longitudinal displacements between the first and second arm members, such as a piezo type actuator.

9. The positioning arm according to claim 1 , wherein a spring member is mounted between the first and the second arm members for providing a return force between the first and second arm members directed towards an offset position of the second arm member relative to the first arm member.

10. The positioning arm according to claim 1 , further comprising a cover enclosing at least a part of the actuator.

11. The positioning arm according to claim 10 , wherein the cover comprises at least one element of a group comprising: a bellows, a flexible cover element, a sleeve, a cloth, or container element.

12. A method of positioning a scan head of a scanning probe microscopy device relative to a support surface,
wherein for performing said placing of the scan head use is made of a positioning arm comprising a base at a first end thereof wherein the base is mounted to a static reference structure, wherein the positioning arm further comprises a first and a second arm member extending from the base, the second arm member extending parallel to the first arm member, wherein the positioning arm comprises a bridge member at a second end thereof, the bridge member connecting the first and the second arm members at said second end of the positioning arm, wherein each one of the first and the second arm members is respectively connected to each one of said base and said bridge member by means of a hingeable connection, and
wherein the method further comprises a step of:
supporting the scan head from a support structure connected to the bridge of the positioning arm; and
moving the support structure by inducing, by means of an actuator comprised by the positioning arm and acting on the first and second arm members, a relative displacement between the first and the second arm members in a longitudinal direction of said first and second arm members, for swinging the second end of the positioning arm in a direction transverse to the relative displacement.

13. The method according to claim 12 , further comprising the steps of:
controlling, by a controller cooperating with the actuator, operation of the actuator for controlling the relative displacement between the first and the second arm members;
wherein the step of controlling includes:
obtaining, by the controller, an amount of said relative displacement between the first and second arm members, and calculating by the controller a transverse displacement of the bridge in a direction transverse to the positioning arm based on the amount of relative displacement.

14. The method according to claim 13 , further comprising:
measuring, using a sensor unit, the relative displacement between the first and the second arm members; and
providing a sensor signal, by the sensor unit to the controller, indicative of said relative displacement.

15. The method according to claim 12 , further comprising providing a return force between the first and second arm members directed towards an offset position of the second arm member relative to the first arm member, wherein said return force is provided by means of a spring member mounted between the first and the second arm members.

Assignees

• TNO

Inventors

• Sadeghian Marnani Hamed
• Winters Jasper
• Crowcombe William Edward

Classifications

• G12B5/00

  Adjusting position or attitude, e.g. level, of instruments or other apparatus, or of parts thereof (levels per se G01C9/00); Compensating for the effects of tilting or acceleration, e.g. for optical apparatus · CPC title

• G01Q10/04 Primary

  Fine scanning or positioning · CPC title

• B23Q1/34

  Relative movement obtained by use of deformable elements, e.g. piezoelectric, magnetostrictive, elastic or thermally-dilatable elements (sensitive elements capable of producing movement or displacement for purposes not limited to measurement G12B1/00) · CPC title

• B23Q2717/00

  Arrangements for indicating or measuring · CPC title