Optical systems for measuring form and geometric dimensions of precision engineered parts
First Claim
1. A method for determining a geometric property of a test object, the method comprising:
- interferometrically profiling a first surface of the test object with respect to a first datum surface;
interferometrically profiling a second surface of the test object with respect to a second datum surface different from the first datum surface;
determining a spatial relationship between the first and second datum surfaces based on at least one interferometric displacement measurement; and
calculating the geometric property based on the interferometrically profiled surfaces and the spatial relationship between the first and second datum surfaces.
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Accused Products
Abstract
The invention features a method for determining a geometric property of a test object, the method including: interferometrically profiling a first surface of the test object in a first coordinate system; interferometrically profiling a second surface of the test object in a second coordinate system different from the first coordinate system; providing a relationship between the first and second coordinate system; and calculating the geometric property based on the interferometrically profiled surfaces and the relationship between the first and second coordinate system. In some embodiments, the relationship may be determined by using calibrated gage blocks or by using a displacement measuring interferometer. Corresponding system are also described.
103 Citations
70 Claims
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1. A method for determining a geometric property of a test object, the method comprising:
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interferometrically profiling a first surface of the test object with respect to a first datum surface;
interferometrically profiling a second surface of the test object with respect to a second datum surface different from the first datum surface;
determining a spatial relationship between the first and second datum surfaces based on at least one interferometric displacement measurement; and
calculating the geometric property based on the interferometrically profiled surfaces and the spatial relationship between the first and second datum surfaces. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method for determining a geometric property of a test object, the method comprising:
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interferometrically profiling a first surface of the test object with respect to a first datum surface;
interferometrically profiling a second surface of the test object with respect to a second datum surface different from the first datum surface;
determining a spatial relationship between the first and second datum surfaces; and
calculating the geometric property based on the interferometrically profiled surfaces and the spatial relationship between the first and second datum surface, wherein the determining of the spatial relationship comprises;
interferometrically profiling a first surface of a initialization artifact with respect to the first datum surface;
interferometrically profiling a second surface of the initialization artifact with respect to the second datum surface;
calculating an initial spatial relationship between the first and second datum surfaces based on at least the profiled surfaces of the initialization artifact; and
adjusting the first and second datum surfaces to accommodate the first and second surfaces of the test object, wherein the first and second surfaces of the initialization artifact are the front and back of a common interface. - View Dependent Claims (36, 37)
interferometrically measuring at least one displacement corresponding to the adjustment of the first and second datum surfaces.
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37. The method of claim 35, further comprising providing at least one calibrated dimension for the initialization artifact, and wherein the calculation of the initial relationship is based on the profiled surfaces of the initialization artifact and the at least one calibrated dimension.
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38. An apparatus for determining a geometric property of a test object, the apparatus comprising:
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an interferometric profiling system which during operation interferometrically profiles a first surface of the test object with respect to a first datum surface and interferometrically profiles a second surface of the test object with respect to a second datum surface different from the first datum surface; and
an electronic processor coupled to the interferometric profiling system, wherein during operation the electronic processor calculates the geometric property based on the interferometrically profiled surfaces and a spatial relationship between the first and second datum surfaces; and
a displacement measuring interferometer positioned to measure the spatial relationship between the first and second datum surfaces. - View Dependent Claims (39, 40)
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41. An apparatus for determining a geometric property of a test object, the apparatus comprising:
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an interferometric profiling system which during operation interferometrically profiles a first surface of the test object with respect to a first datum surface and interferometrically profiles a second surface of the test object with respect to a second datum surface different from the first datum surface; and
an electronic processor coupled to the interferometric profiling system, wherein during operation the electronic processor calculates the geometric based on the interferometrically profiled surfaces and a spatial relationship between the first and second datum surfaces, wherein the interferometric profiling system comprises an interferometric optical profiler having a first viewing port for viewing the first surface of the test object and a second viewing port for viewing the second surface of the test object, wherein the first and second surfaces correspond to different sides of the test object. - View Dependent Claims (42, 43, 44)
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45. An apparatus for determining a geometric property of a test object, the apparatus comprising:
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an interferometric profiling system which during operation interferometrically profiles a first surface of the test object with respect to a first datum surface and interferometrically profiles a second surface of the test object with respect to a second datum surface different from the first datum surface; and
an electronic processor coupled to the interferometric profiling system, wherein during operation the electronic processor calculates the geometric property based on the interferometrically profiled surfaces and a spatial relationship between the first and second datum surfaces, wherein the interferometric profiling system comprises an interferometric optical profiler having a first viewing port for viewing the first surface of the test object and a second viewing port for viewing the second surface of the test object, and wherein the optical profiler is configured to direct a first portion of EM radiation from a source towards the first viewing port, direct a second portion of the EM radiation towards the second viewing port, and direct at least one additional portion of the EM radiation within the optical profiler. - View Dependent Claims (46, 47, 48)
48.The apparatus of claim 47, wherein the optical profiler further includes a transducer the reference surface for scanning the position of the reflective reference surface. -
48. The apparatus of claim 46, wherein the optical profiler further comprises a first viewing port optic supported by a first movable stage, the first viewing port optic positioned to direct at least one part of the first portion of the EM radiation towards the first surface of the test object and the first movable stage adjustable to accommodate the interferometric profiling of the first surface of the test object.
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- 49. The apparatus of claim 49, wherein the optical profiler further comprises a second viewing port optic supported by a second movable stage, the second viewing port optic positioned to direct at least one part of the second portion of the EM radiation towards the second surface of the test object and the second movable stage adjustable to accommodate the interferometric profiling of the second surface of the test object.
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50. The apparatus of claim 50 further comprising a displacement measuring interferometer positioned to measure changes in the spatial relationship between the first and second datum surfaces caused by at least one of an adjustment to the first movable stage and an adjustment to the second movable stage.
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53. An apparatus for determining a geometric property of a test object, the apparatus comprising:
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an interferometric profiling system which during operation interferometrically profiles a first surface of the test object with respect to a first datum surface and interferometrically files a second surface the test object with respect to a second datum surface different from the first datum surface; and
an electronic processor coupled to the interferometric profiling system, wherein during operation the electronic processor calculates the geometric property based on the interferometrically profiled surfaces and a spatial relationship between the first and second datum surfaces, wherein the interferometric profiling system comprises a first interferometric optical profiler for viewing the first surface of the test object and a second interferometric optical profiler for viewing the second surface of the test object.
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54. The apparatus of claim 54, wherein the first optical profiler is movable relative to the second optical profiler to adjust the spatial relationship between the first and second datum surfaces.
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55. The apparatus of claim 55, further comprising a displacement measuring interferometer positioned to measure changes in the spatial relationship between the first and second datum surfaces caused by relative movement of the first and second optical profilers.
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56. An apparatus for determining a geometric property of a test object the apparatus comprising:
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an interferometric profiling system which during operation interferometrically profiles a first surface of the test object with respect to a first datum surface and interferometrically profiles a second surface of the test object with respect to a second datum surface different from the first datum surface;
an electronic processor coupled to the interferometric profiling system, wherein during operation the electronic processor calculates the geometric property based on the interferometrically profiled surfaces and a spatial relationship between the first and second datum surfaces; and
a gauge object having first and second surfaces, the first surface being positioned to be profiled by the interferometric profiling system with respect to the first datum surface and the second surface being positioned to be profiled by the interferometric profiling system with respect to the second datum surface, wherein the gauge object is positioned to be in a field of view of the interferometric profiling system during interferometric profiling of the test object.
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- 57. The apparatus of claim 57, wherein the electronic processor determines the spatial relationship between the first and second datum surfaces based on interferometric profiling measurements of the first and second surfaces of the gauge object provided by the first and second optical profilers.
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59. An apparatus for determining a geometric property of a test object, the apparatus comprising:
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an interferometric profiling system which during operation interferometrically profiles a first surface of the test object with respect to a first datum surface and interferometrically profiles a second surface of the test object with respect to a second datum surface different from the first datum surface; and
an electronic processor coupled to the interferometric profiling system, wherein during operation the electronic processor calculates the geometric property based on the interferometrically profiled surfaces and a spatial relationship between the first and second datum surfaces;
wherein the electronic processor uses at least one value indicative of PCOR dispersion in the interferometric profiling system and the test object to calculate the geometric property.
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60. An apparatus for determining a geometric property of a test object, the apparatus comprising:
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an interferometric profiling system which during operation interferometrically profiles a first surface of the test object with respect to a first datum surface and interferometrically profiles a second surface of the test object with respect to a second datum surface, wherein the interferometric profiling system comprises at least one movable stage for adjusting the position of the first datum surface and the second datum surface;
a displacement measuring interferometer positioned to measure a change in a relative position of the first and second datum surface caused by an adjustment to the at least one movable stage; and
an electronic processor coupled to the interferometric profiling system and the displacement measuring interferometer, wherein during operation the electronic processor calculates the geometric property based on the interferometrically profiled surfaces and the relative position of the first and second datum surfaces.
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- 61. The apparatus of claim 61, wherein the interferometric profiling system comprises a second moveable stage, and wherein during operation the first-mentioned movable stage adjusts the position of the first datum surface and the second movable stage adjusts the position of the second datum surface.
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65. A method for determining a geometric property of a test object, the method comprising:
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interferometrically profiling a first surface of the test object with respect to a first datum surface;
interferometrically profiling a second surface of the test object with respect to a second datum surface different from the first datum surface;
determining a spatial relationship between the interferometrically profiled surfaces which accounts for PCOR dispersion; and
calculating the geometric property based on the interferometrically profiled surfaces and the spatial relationship.
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66. A method for determining a geometric property of a test object, the method comprising:
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interferometrically profiling a first surface of the test object with respect to a first datum surface;
interferometrically profiling a second surface of the test object with respect to a second datum surface different from the first datum surface;
providing a spatial relationship between the first and second datum surfaces based on at least one interferometric displacement measurement; and
calculating the geometric property based on the interferometrically profiled surfaces and the spatial relationship between the first and second datum surfaces, wherein the first and second surfaces of the test object are interferometrically profiled from a common side and the first and second datum surfaces are spaced from one another by a distance greater than a profiling range η
of an interferometry system used for the interferometric profiling steps.
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67. The method of claim 67, wherein the interferometry system used for the interferometric profiling steps comprises a reference object having a partially reflective, first surface and a reflective, second surface, the first surface defining a position of the first datum surface and the second surface defining a position of the second datum surface.
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68. The method of claim 68, wherein the relationship is defined by the spatial separation between the first and second surfaces of the reference object.
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69. An optical profiling system comprising:
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a broadband source;
a scanning interferometer which during operation separates input light into a first wavefront and a second wavefront, directs the first wavefront along a reference path including a partially reflective first surface and a reflective second surface and the second wavefront along a measurement path contacting a measurement object, and, after the second wavefront contacts the measurement object, combines the wavefronts to produce an optical interference pattern;
a detector producing interference data in response to the optical interference pattern;
an electronic processor coupled to the detector for analyzing the interference data a scanning controller coupled to the scanning interferometer and the electronic processor, wherein during operation the scanning controller causes the scanning interferometer to adjust the position of the first and second surfaces.
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70. The interferometry system of claim 70, wherein the partially reflective first surface of the scanning interferometer defines a position of a first datum surface and the reflective second surface defines a position of a second datum surface, and wherein during operation the electronic processor calculates a geometric property of the test object based on the interference data and a relationship between the first and second datum surfaces.
Specification