Displacement detector, surface shape measuring apparatus, and roundness measuring apparatus

Patent metadata

Field	Value
Publication number	US-11435175-B2
Application number	US-202117336794-A
Country	US
Kind code	B2
Filing date	Jun 2, 2021
Priority date	Apr 16, 2019
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

Provided are a displacement detector, a surface shape measuring apparatus, and a roundness measuring apparatus capable of measuring displacement in a plurality of directions, having a simple configuration, and capable of highly accurate measurement. A displacement measurer includes: a detector body; a substantially L-shaped stylus having a contactor to be in contact with a measuring surface of an object to be measured; a stylus holding part that is provided in the detector body and holds the stylus in a swingable manner, with a swing plane being a plane including a first direction and a second direction that are perpendicular to each other; and a displacement detecting unit that is provided in the detector body and detects displacement of the contactor associated with contact between the contactor and the measuring surface.

First claim

What is claimed is:

1. A displacement detector comprising:
a detector body;
a stylus having a contactor configured to be brought into contact with a measuring surface of an object to be measured;
a stylus holding part provided in the detector body and configured to hold the stylus that is capable of being swung along a swing plane including a first direction and a second direction that are perpendicular to each other; and
a displacement detecting unit provided in the detector body and configured to detect displacement of the contactor in association with contact between the contactor and the measuring surface, wherein
the stylus comprises:
a first arm which has a first one end portion and a first another end portion, and extends in the first direction from the first one end portion toward the first another end portion, the first one end portion being held by the stylus holding part; and
a second arm which has a second one end portion and a second another end portion and extends in the second direction from the second one end portion toward the second another end portion, the second one end portion being connected to the first another end portion and the second another end portion being provided with the contactor, and
the displacement detecting unit is capable of detecting displacement in the first direction and displacement in the second direction as the displacement of the contactor without a change in attitude of the detector body, based on a displacement amount of the contactor and an angle formed between a line connecting a center of the contacting element with a rotational axis of the stylus, and a vertical line.

2. The displacement detector according to claim 1 , wherein the stylus holding part is attached to the detector body via an elastic body in a swingable manner.

3. The displacement detector according to claim 1 , wherein, when the contactor is displaced, the displacement detecting unit can detect displacement in the first direction and displacement in the second direction, as the displacement of the contactor.

4. The displacement detector according to claim 1 , wherein the displacement detecting unit has a calibration value for each of the first direction and the second direction.

5. The displacement detector according to claim 1 , wherein:
the displacement detecting unit comprises a differential transformer having a core and a plurality of coils; and
the stylus holding part supports the core at an end portion on a side opposite to a side on which the stylus is supported, seen from the swing center.

6. The displacement detector according to claim 1 , wherein the stylus is pivotally supported via the stylus holding part to be swingable around the rotational axis perpendicular to the swing plane.

7. The displacement detector according to claim 6 , comprising
a measurement force applying part configured to apply a force biasing the contactor in a direction toward the measuring surface.

8. The displacement detector according to claim 1 , wherein, assuming that a contactor direction is a direction from a swing center of the stylus toward the contactor, the contactor direction includes a component in the first direction and a component in the second direction.

9. The displacement detector according to claim 8 , wherein, in a state in which the contactor is not in contact with the measuring surface, a ratio of the component in the first direction to the component in the second direction falls within a range from 1:0.58 to 1:1.73.

10. The displacement detector according to claim 8 , wherein, in a state in which the contactor is not in contact with the measuring surface, a ratio of the component in the first direction to the component in the second direction falls within a range from 1:0.75 to 1:1.33.

11. The displacement detector according to claim 8 , wherein, in a state in which the contactor is not in contact with the measuring surface, the component in the first direction is equal to the component in the second direction.

12. A surface shape measuring apparatus comprising:
the displacement detector according to claim 1 ; and
a moving mechanism configured to hold the displacement detector and move the displacement detector relatively to the object to be measured in a horizontal direction and a perpendicular direction perpendicular to the horizontal direction.

13. The surface shape measuring apparatus according to claim 12 , further comprising
a control unit configured to detect a measurement direction of the displacement detector based on a moving direction of the moving mechanism when the contactor of the displacement detector is brought into contact with the object to be measured at start of measurement.

14. The surface shape measuring apparatus according to claim 13 , wherein the control unit detects the measurement direction of the displacement detector based on a signal that controls driving of the moving mechanism.

15. A roundness measuring apparatus comprising:
the displacement detector according to claim 1 ; and
a rotary stage configured to rotate the object to be measured around a stage rotational axis that is parallel to the perpendicular direction.

16. The roundness measuring apparatus according to claim 15 , further comprising:
a moving mechanism configured to hold the displacement detector and move the displacement detector relatively to the object to be measured in a horizontal direction and a perpendicular direction perpendicular to the horizontal direction; and
a control unit configured to detect a measurement direction of the displacement detector based on a moving direction of the moving mechanism when the contactor of the displacement detector is brought into contact with the object to be measured at start of measurement.

17. The roundness measuring apparatus according to claim 16 , wherein the control unit detects the measurement direction of the displacement detector based on a signal that controls driving of the moving mechanism.

18. A displacement detector comprising:
a detector body;
a stylus having a contactor to be in contact with a measuring surface of an object to be measured;
a stylus holding part that is provided in the detector body and holds the stylus that is capable of being swung; and
a displacement detecting unit that is provided in the detector body and detects displacement of the contactor associated with contact between the contactor and the measuring surface,
wherein:
the stylus has a first arm and a second arm that are perpendicular to each other; and
the displacement detecting unit is capable of detecting displacement in a longitudinal direction of the first arm and displacement in a longitudinal direction of the second arm as the displacement of the contactor without a change in attitude of the detector body, based on a displacement amount of the contactor and an angle formed between a line connecting a center of the contactor with a rotational axis of the stylus, and a vertical line.

Assignees

• Tokyo Seimitsu Co Ltd

Inventors

• Morii Hideki

Classifications

• G01B21/042

  Calibration or calibration artifacts (G01B3/30, G01B9/02072 take precedence) · CPC title

• G01B5/016 Primary

  Constructional details of contacts · CPC title

• G01B5/201 Primary

  for measuring roundness · CPC title

• G01B7/001 Primary

  Constructional details of gauge heads (G01B7/012 takes precedence) · CPC title

• G01B5/20 Primary

  for measuring contours or curvatures · CPC title