US5289267A — Electro-optical system for gauging surface profil…

Claim 1

Independent Claim 265 words

A system for gauging deviations of a surface on a test part from a preselected nominal surface geometry using electromagnetic radiation, said system comprising: (1) a master surface that is substantially a matched surface of the preselected nominal surface geometry and that is essentially transparent to the electromagnetic radiation; (2) an attenuating medium on the master surface with the test part being supportable on the master surface with the surface of the test part opposed to the master surface such that the attenuating medium substantially fills all space to be gauged between the master surface and the test part surface; (3) a source of electromagnetic radiation positioned to direct such radiation through the master surface and into the attenuating medium; (4) an image sensor positioned to receive the electromagnetic radiation transmitted from the test part surface to be gauged and which passes back through the attenuating medium, whereby an image of the test part surface to be gauged is formed, the intensity of the transmitted radiation varying across the image as a function of the deviation of the test part surface from the preselected nominal surface geometry; (5) a digitizer for converting the image from the image sensor into digital signals indicative to the intensity of the radiation at locations of the image; (6) digital electronic storage coupled to the digitizer for receiving and storing the digital signals; and (7) a calibration arrangement for correcting errors in the image formed by the image sensor, including means for producing a set of correction data and for altering the digital signals in accordance with the correction data.

Claim 2

Independent Claim 265 words

A system for gauging deviations of a surface on a test part from a preselected nominal surface geometry using electromagnetic radiation, said system comprising: (1) a master surface that is substantially a matched surface of the preselected nominal surface geometry and that is essentially transparent to the electromagnetic radiation; (2) an attenuating medium on the master surface with the test part being supportable on the master surface with the surface of the test part opposed to the master surface such that the attenuating medium substantially fills all space to be gauged between the master surface and the test part surface; (3) a source of electromagnetic radiation positioned to direct such radiation through the master surface and into the attenuating medium; (4) an image sensor positioned to receive the electromagnetic radiation transmitted from the test part surface to be gauged and which passes back through the attenuating medium, whereby an image of the test part surface to be gauged is formed, the intensity of the transmitted radiation varying across the image as a function of the deviation of the test part surface from the preselected nominal surface geometry; (5) a digitizer for converting the image from the image sensor into digital signals indicative to the intensity of the radiation at locations of the image; (6) digital electronic storage coupled to the digitizer for receiving and storing the digital signals; and (7) a calibration arrangement for correcting errors in the image formed by the image sensor, including means for producing a set of correction data and for altering the digital signals in accordance with the correction data.

Claim 3

Dependent Claim 32 words

A system as defined in claim 1, wherein the attenuating medium includes a material for attenuating the electromagnetic radiation as a function of distance the electromagnetic radiation travels through the attenuating medium.

Claim 4

Dependent Claim 26 words

A system as defined in claim 2, wherein the attenuating medium is a liquid containing a dye and the electromagnetic radiation is in the visible range.

Claim 5

Dependent Claim 25 words

A system as defined in claim 2, wherein the attenuating medium is conductive to microwave radiation and the electromagnetic radiation is in the microwave range.

Claim 6

Dependent Claim 35 words

A system as defined in claim 1, wherein the surface of the test part has low reflectivity and the attenuating medium contains a fluorescent dye responsive to the electromagnetic radiation from the electromagnetic radiation source.

Claim 7

Dependent Claim 30 words

A system as defined in claim 1, wherein the attenuating medium contains a photochromic dye having attenuation characteristics that vary as a function of the intensity of the electromagnetic radiation.

Claim 8

Dependent Claim 57 words

A system as defined in claim 1, wherein the image sensor is a CCD sensor having a matrix of image sensing elements in a row-and-column array, each of the image sensing elements receiving a corresponding location of the image such that the resolution of the system depends upon number, size, and spacing between the image sensing elements.

Claim 9

Dependent Claim 30 words

A system as defined in claim 7 further comprising a translator for moving the image sensor relative to the master surface so as to vary the resolution of the system.

Claim 10

Dependent Claim 108 words

A system as defined in claim 1, wherein the calibration arrangement includes: (1) one or more filters which can be positioned in the light path between the electromagnetic radiation source and the image sensor in order to vary the wavelength of light collected at the image source; (2) means for storing digital signals from the image sensor at a minimum of two different wavelengths; (3) means for calculating calibration signals based on the digital signals stored from the different wavelengths measurements; and (4) means for storing the calibration signals; whereby the calibration signals can be used to correct for non-uniform reflectivity from the surface of the test part.

Claim 11

Dependent Claim 59 words

A system as defined in claim 1, wherein the calibration arrangement includes: (1) means for measuring and storing the intensity of the radiation reflected from the test surface at each image location without any attenuating medium present; and (2) means for using the measured reflection at each image location to correct the measurement made with the attenuating medium present.

Claim 12

Dependent Claim 95 words

A system as defined in claim 1, wherein the calibration arrangement includes: (1) a standard test part having the preselected nominal surface geometry and uniform reflectivity positioned on the master surface; (2) means for storing digital signals from the image sensor indicative of intensity of light reflected by the standard test part; (3) means for calculating calibration signals based on the digital signals stored from the standard test part measurement; and (4) means for storing the calibration signals; wherein the calibration signals can be used to correct for non-uniform illumination of the test part surface.

Claim 13

Dependent Claim 32 words

A system as defined in claim 1, wherein a screen display is coupled to the digital electronic storage for displaying the deviations from the preselected nominal surface geometry of the test part.

Claim 14

Dependent Claim 39 words

A system as defined in claim 1, wherein the test part is supported on the master surface by a plurality of shims where at least one of the shims has a calibration groove or slot of precisely known depth.

Claim 15

Dependent Claim 28 words

A system as defined in claim 13, wherein the master surface is an optical flat and the system is used to determine the flatness of the test part.

Claim 16

Dependent Claim 38 words

A system as defined in claim 13, wherein the master surface is a glass plate which is calibrated using a standard optical flat test part and the system is used to determine flatness of the non-standard test part.

Claim 17

Independent Claim 253 words

A method of gauging deviations of a surface on a test part from a preselected nominal surface geometry using electromagnetic radiation and a master surface that is essentially transparent to the electromagnetic radiation and that contains a substantially matched surface of the preselected nominal surface geometry, said method comprising: (1) forming an attenuating medium layer on the master surface; (2) placing the test part on the attenuating medium layer such that the surface of the test part is opposed to the corresponding matched surface of the master surface and such that substantially all spaces to be gauged between the test part surface and the master surface are essentially filled with attenuating medium; (3) passing electromagnetic radiation into the attenuating medium in the direction of the test part surface; (4) collecting the electromagnetic radiation which is transmitted from the test part surface and which passes back through the attenuating medium to form an image of the transmitted electromagnetic radiation; (5) digitizing the image of the transmitted electromagnetic radiation; (6) storing the digitized image in an electronic storage device associated with a computer; (7) determining the deviations of the surface of the test part from a preselected nominal surface geometry, whereby the intensity of the transmitted electromagnetic radiation varies across the image as a function of the deviation of the test part surface from the preselected nominal surface geometry; (8) producing a set of correction data related to errors in the digitized image; and, (9) altering the digitized image in accordance with the correction data.

Claim 18

Independent Claim 253 words

A method of gauging deviations of a surface on a test part from a preselected nominal surface geometry using electromagnetic radiation and a master surface that is essentially transparent to the electromagnetic radiation and that contains a substantially matched surface of the preselected nominal surface geometry, said method comprising: (1) forming an attenuating medium layer on the master surface; (2) placing the test part on the attenuating medium layer such that the surface of the test part is opposed to the corresponding matched surface of the master surface and such that substantially all spaces to be gauged between the test part surface and the master surface are essentially filled with attenuating medium; (3) passing electromagnetic radiation into the attenuating medium in the direction of the test part surface; (4) collecting the electromagnetic radiation which is transmitted from the test part surface and which passes back through the attenuating medium to form an image of the transmitted electromagnetic radiation; (5) digitizing the image of the transmitted electromagnetic radiation; (6) storing the digitized image in an electronic storage device associated with a computer; (7) determining the deviations of the surface of the test part from a preselected nominal surface geometry, whereby the intensity of the transmitted electromagnetic radiation varies across the image as a function of the deviation of the test part surface from the preselected nominal surface geometry; (8) producing a set of correction data related to errors in the digitized image; and, (9) altering the digitized image in accordance with the correction data.

Claim 19

Dependent Claim 33 words

A method as defined in claim 16, wherein the attenuating medium includes a material for attenuating the electromagnetic radiation as a function of the distance the electromagnetic radiation travels through the attenuating medium.

Claim 20

Dependent Claim 26 words

A method as defined in claim 17, wherein the attenuating medium is a liquid containing a dye and the electromagnetic radiation is in the visible range.

Claim 21

Dependent Claim 25 words

A method as defined in claim 17, wherein the attenuating medium is conductive to microwave radiation and the electromagnetic radiation is in the microwave range.

Claim 22

Dependent Claim 22 words

A method as defined in claim 17, wherein a camera is used to collect the electromagnetic radiation transmitted from the attenuating medium.

Claim 23

Dependent Claim 53 words

A method as defined in claim 20, wherein the camera is a CCD sensor having a matrix of usage sensing elements in a row-and-column array, each of the image sensing elements receiving a corresponding location of the image such that the resolution depends upon number, size, and spacing between the image sensing elements.

Claim 24

Dependent Claim 23 words

A method as defined in claim 21, wherein the camera is movable relative to the matter surface so as to vary the resolution.

Claim 25

Dependent Claim 30 words

A method as defined in claim 16, wherein the surface of the test part has low rejectivity and the attenuating medium contains a fluorescent dye responsive to the electromagnetic radiation.

Claim 26

Dependent Claim 30 words

A method as defined in claim 16, wherein the attenuating medium contains a photochromic dye having attenuation characteristics that vary as a function of the intensity of the electromagnetic radiation.

Claim 27

Dependent Claim 93 words

A method as defined in claim 16, wherein steps (8) and (9) are performed by: (1) positioning one or more filters in the electromagnetic radiation path in order to vary the wavelength of the electromagnetic radiation collected to form the image; (2) storing the digital signals collected at a minimum of two different wavelengths; (3) calculating calibration signals based on the digital signals stored from the different wavelengths measurements; and (4) storing the calibration signals; whereby the calibration signals are used to correct for non-uniform reflectivity from the surface of the test part.

Claim 28

Dependent Claim 60 words

A method as defined in claim 16, wherein steps (8) and (9) are performed by: (1) measuring and storing the intensity of the radiation reflected from the test surface at each image pixel location without any attenuating medium present; and (2) using the measured reflection at each image pixel location to correct the measurement made with the attenuating medium present.

Claim 29

Dependent Claim 92 words

A method as defined in claim 16, wherein steps (1) and (2) are performed by: (1) positioning a standard test part having the preselected nominal surface geometry and uniform reflectivity on the master surface; (2) storing digital signals from the collected electromagnetic radiation indicative of intensity of light reflected by the standard test part; (3) calculating calibration signals based on the digital signals stored from the standard test part measurement; and (4) storing the calibration signals; whereby the calibration signals are used to correct for non-uniform illumination of the test part surface.

Claim 30

Dependent Claim 25 words

A method as defined in claim 16, wherein the deviations from the preselected nominal surface geometry of the test part are displayed on a screen.

Claim 31

Dependent Claim 41 words

A method as defined in claim 16, wherein the test part is placed and supported on the master surface by a plurality of shims where at least one of the shims has a calibration groove or slot of precisely known depth.

Claim 32

Dependent Claim 28 words

A method as defined in claim 29, wherein the master surface is an optical flat and the method is used to determine the flatness of the test part.

Claim 33

Dependent Claim 38 words

A method as defined in claim 29, wherein the master surface is a glass plate which is calibrated using a standard optical flat test part and the method is used to determine flatness of the non-standard test part.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1997-02-21	1997-08-23	1998-02-22	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2001-02-21	2001-08-23	2002-02-22	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2005-02-21	2005-08-23	2006-02-22	$7700.00	Window Closed / Lapsed

Electro-optical system for gauging surface profile deviations

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag