SURFACE MEASUREMENT INSTRUMENT AND METHOD
First Claim
1. A method of determining a correction parameter for use in effecting alignment of a component of a metrological apparatus in at least one direction, the method comprising:
- positioning an artefact on a support surface of the metrological apparatus;
using a measurement probe of a measurement instrument to make a first measurement of the measurement surface;
effecting relative rotation of the measurement surface about a rotation axis such that a measurement surface of the artefact is asymmetric with respect to the rotation axis in the at lest one direction;
using the measurement probe of the measurement instrument to make a second measurement of the measurement surface after the rotation; and
determining a correction parameter from the first and second measurements.
1 Assignment
0 Petitions
Accused Products
Abstract
A method of determining a correction parameter for use in effecting alignment of a component of a metrological apparatus in at least one direction is described which includes: positioning an artefact on a support surface of a turntable of the metrological apparatus so that a measurement surface of the artefact is asymmetric with respect to a rotation axis of the turntable in the at least one direction; using a measurement probe of the measurement instrument to make a first measurement of the measurement surface; rotating the turntable; using the measurement probe of the measurement instrument to make a second measurement of the measurement surface after rotation of the turntable; and determining a correction parameter from the first and second measurements.
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Citations
64 Claims
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1. A method of determining a correction parameter for use in effecting alignment of a component of a metrological apparatus in at least one direction, the method comprising:
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positioning an artefact on a support surface of the metrological apparatus; using a measurement probe of a measurement instrument to make a first measurement of the measurement surface; effecting relative rotation of the measurement surface about a rotation axis such that a measurement surface of the artefact is asymmetric with respect to the rotation axis in the at lest one direction; using the measurement probe of the measurement instrument to make a second measurement of the measurement surface after the rotation; and determining a correction parameter from the first and second measurements. - View Dependent Claims (2, 3, 5, 7, 8, 11, 12, 15, 16, 57)
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4. (canceled)
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6. (canceled)
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9-10. -10. (canceled)
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13-14. -14. (canceled)
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17-19. -19. (canceled)
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20. A method of determining an alignment correction parameter for centering a workpiece having first and second mirror image surface portions to a rotation axis of a turntable of a metrological apparatus, the method comprising:
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measuring a form of the first surface portion at a first measurement position to provide first measurement data; rotating the turntable to bring the second surface portion to the first measurement position; measuring a form of the second surface portion at the first measurement position to provide second measurement data; aligning the first and second measurement data using a feature of the form of the first and second surface portions; and determining an alignment correction parameter based on results of the aligning. - View Dependent Claims (21, 22, 23)
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24-28. -28. (canceled)
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29. Metrological apparatus comprising:
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a turntable; means for determining a correction parameter for use in effecting alignment of a component of the metrological apparatus in at least one direction; an artefact mounted on a support surface of the turntable of the metrological apparatus so that a measurement surface of the artefact is asymmetric with respect to a rotation axis of the turntable in the at least one direction; a measurement probe to make measurements on the measurement surface; and means for rotating the turntable, wherein the determining means is arranged to determine the correction parameter from a first measurement of the measurement surface by the measurement probe and a second measurement of the measurement surface by the measurement probe after rotation of the turntable.
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30-47. -47. (canceled)
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48. Metrological apparatus comprising:
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a turntable to support a workpiece having first and second mirror image surface portions; means for measuring surface form; means for rotating the turntable about a rotation axis; control means for causing;
the measuring means to measure a form of the first surface portion at a first measurement position to provide first measurement data, the rotating means to rotate the turntable to bring the second surface portion to the first measurement position, and the measuring means to measure a form of the second surface portion at the first measurement position to provide second measurement data;means for aligning the first and second measurement data using a feature of the form of the first and second surface portions; and means for determining an alignment correction parameter to centre the workpiece to the rotation axis based on results of the aligning.
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49-56. -56. (canceled)
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58-60. -60. (canceled)
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61. Metrological apparatus comprising:
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a rotatable turntable; a processor for determining a correction parameter for use in effecting alignment of a component of the metrological apparatus in at least one direction; an artefact mounted on a support surface of the turntable of the metrological apparatus so that a measurement surface of the artefact is asymmetric with respect to a rotation axis of the turntable in the at least one direction; a measurement probe to make measurements on the measurement surface; and wherein the processor is arranged to determine a correction parameter from a first measurement of the measurement surface by the measurement probe and a second measurement of the measurement surface by the measurement probe after rotation of the turntable.
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62. Metrological apparatus comprising:
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a rotatable turntable to support a workpiece having first and second mirror image surface portions, wherein the a rotatable turntable is rotatable about a rotation axis; a measurement probe for measuring surface form; a control mechanism for causing; the measurement probe to measure the form of the first surface portion at a first measurement position to provide first measurement data; the rotatable turntable to rotate to bring the second surface portion to the first measurement position; and the measuring probe to measure the form of the second surface portion at the first measurement position to provide second measurement data; the apparatus further comprising a processor configured to align the first and second measurement data using a feature of the form of the first and second surface portions and further configured to determine an alignment correction parameter to centre the workpiece to the rotation axis based on results of the aligning. - View Dependent Claims (63, 64)
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Specification