US3586865A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of,and apparatus for,inspecting the shape of small objects
Assignee: BRITISH SCIENT INSTR RESEARCH
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Filing: 1969-06-19
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Granted: 1971-06-22
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Expires: 1989-06-19
Abstract
Abstract A method of and apparatus for ascertaining the profile, uniformity or some other related characteristic of a small object or part of a small object. An optical image of the part of the object under investigation, for example the cutting edge of a cutting tool, is formed and the distribution of intensity of radiation in the image which is formed by light reflected diffracted and/or scattered by the object is Fourier analyzed by optical scanning to provide an electrical signal representing the Fourier transform of the intensity of radiation in said image. A complete transform over a range of spatial frequencies can be provided. Alternatively once a reference transform is known a comparison can be made between the electrical signal produced by a standard object and that produced by the object under test at one or more spatial frequencies.
Inventors
- 👤 Lionel Richard Baker
- 👤 Peter Archer
- 👤 Patricia Ann West
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:10
CPC Classifications
G; G01; G01B; G01B11/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
105 words
A method of ascertaining the profile or uniformity of a portion of a small object, said method comprising the steps of: a. subjecting said portion of the object to a beam of electromagnetic radiation, b. scanning radiation generally reflected by said portion to periodically modulate the intensity of said radiation at one or more selected spatial frequencies, c. producing an electrical signal from the scanned radiation which signal forms part of a Fourier transform response of the mean intensity of said radiation at each selected spatial frequency, and d. comparing the electrical signal with that produced by a reference object at a particular spatial frequency.
Claim 2
Independent Claim
105 words
A method of ascertaining the profile or uniformity of a portion of a small object, said method comprising the steps of: a. subjecting said portion of the object to a beam of electromagnetic radiation, b. scanning radiation generally reflected by said portion to periodically modulate the intensity of said radiation at one or more selected spatial frequencies, c. producing an electrical signal from the scanned radiation which signal forms part of a Fourier transform response of the mean intensity of said radiation at each selected spatial frequency, and d. comparing the electrical signal with that produced by a reference object at a particular spatial frequency.
Claim 3
Independent Claim
112 words
A method of ascertaining the profile or uniformity of a portion of a small object, said method comprising the steps of: a. scanning a beam of electromagnetic radiation to periodically modulate the intensity of said radiation at one or more selected spatial frequencies, b. directing said scanned radiation at said portion of the object, c. collecting scanned radiation generally reflected by said portion of the object, d. producing an electrical signal from the collected radiation forming part of a Fourier transform response of the mean intensity of said radiation at each selected spatial frequency, and e. comparing the electrical signal with that produced by a reference object at a particular spatial frequency.
Claim 4
Independent Claim
112 words
A method of ascertaining the profile or uniformity of a portion of a small object, said method comprising the steps of: a. scanning a beam of electromagnetic radiation to periodically modulate the intensity of said radiation at one or more selected spatial frequencies, b. directing said scanned radiation at said portion of the object, c. collecting scanned radiation generally reflected by said portion of the object, d. producing an electrical signal from the collected radiation forming part of a Fourier transform response of the mean intensity of said radiation at each selected spatial frequency, and e. comparing the electrical signal with that produced by a reference object at a particular spatial frequency.
Claim 5
Dependent Claim
26 words
A method according to claim 2, wherein the spatial frequency is varied over a range of values so that the electrical signal is an analog signal.
Claim 6
Independent Claim
100 words
A method of ascertaining the profile or uniformity of a portion of a small object, said method comprising the steps of: a. subjecting said portion of the object to a beam of electromagnetic radiation, b. scanning the radiation to periodically modulate its intensity at variouS spatial frequencies, c. collecting scanned radiation generally reflected by said object, d. producing an electrical signal from the collected scanned radiation forming part of a Fourier transform response of the mean intensity of said radiation, and e. comparing said signal with a reference signal representing a standard object having a corresponding portion of desired characteristics.
Claim 7
Independent Claim
100 words
A method of ascertaining the profile or uniformity of a portion of a small object, said method comprising the steps of: a. subjecting said portion of the object to a beam of electromagnetic radiation, b. scanning the radiation to periodically modulate its intensity at variouS spatial frequencies, c. collecting scanned radiation generally reflected by said object, d. producing an electrical signal from the collected scanned radiation forming part of a Fourier transform response of the mean intensity of said radiation, and e. comparing said signal with a reference signal representing a standard object having a corresponding portion of desired characteristics.
Claim 8
Dependent Claim
21 words
A method according to claim 4, wherein the electrical signal is an analog signal corresponding to a range of spatial frequencies.
Claim 9
Independent Claim
176 words
An apparatus for ascertaining the sharpness of a portion of an object, said apparatus comprising; a. a source of electromagnetic radiation, b. a rotatable radiation-transmitting disc having radial grating lines thereon and arranged to scan a beam of radiation emitted by said source, c. means for rotating said disc at a constant speed, d. a variable-dimension slit for selecting an elongated part of the scanned radiation beam, e. means for bodily displacing the rotational axis of said disc relative to said slit to vary the spatial frequency at which the intensity of the beam is modulated by said disc, f. means for imaging said selected part of the scanned radiation beam onto said portion of the object for reflection thereby, g. a beam splitter for passing said selected part of the scanned radiation onto said portion of the object and for redirecting radiation generally reflected from said portion, and h. means for collecting said redirected radiation and for converting said collected radiation into an electrical signal having a value indicative of the sharpness of said portion.
Claim 10
Independent Claim
176 words
An apparatus for ascertaining the sharpness of a portion of an object, said apparatus comprising; a. a source of electromagnetic radiation, b. a rotatable radiation-transmitting disc having radial grating lines thereon and arranged to scan a beam of radiation emitted by said source, c. means for rotating said disc at a constant speed, d. a variable-dimension slit for selecting an elongated part of the scanned radiation beam, e. means for bodily displacing the rotational axis of said disc relative to said slit to vary the spatial frequency at which the intensity of the beam is modulated by said disc, f. means for imaging said selected part of the scanned radiation beam onto said portion of the object for reflection thereby, g. a beam splitter for passing said selected part of the scanned radiation onto said portion of the object and for redirecting radiation generally reflected from said portion, and h. means for collecting said redirected radiation and for converting said collected radiation into an electrical signal having a value indicative of the sharpness of said portion.
Claim 11
Dependent Claim
63 words
An apparatus according to claim 6, wherein the means for passing radiation onto said portion of the object includes a convex lens positioned to transmit radiation passed through said beam splitter and radiation reflected by said portion, and a variable-size aperture positioned between the beam splitter and the lens and used to control the angular spread of the radiation reflected by said portion.
Claim 12
Dependent Claim
57 words
An apparatus according to claim 6, wherein the means for producing an electrical signal is composed of the series combination of a radiation diffuser for collecting the reflected radiation, a photoelectric device for converting the output of said diffuser into an electrical signal, an amplifier for amplifying said signal and a filter for filtering said amplified signal.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-21 | 1974-12-21 | 1975-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-21 | 1978-12-21 | 1979-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-21 | 1982-12-21 | 1983-06-22 | $7700.00 | Window Closed / Lapsed |