US3836787A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for examining the surface of an object using electromagnetic radiation
Assignee: National Research Development Corp UK
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Filing: 1972-07-07
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Granted: 1974-09-17
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Expires: 1992-07-07
Abstract
Abstract In order to examine the surface of an object to view detail substantially smaller than the wavelength of the radiation used, the object is mounted behind a plate having an aperture of size equal to the desired resolution and radiation is directed on to the plate and thence, through the aperture on to the surface of the object. The object is vibrated relative to the plate so that light reflected from the surface of the object back through the aperture is modulated with the frequency of this vibration and can thus be distinguished from radiation reflected from the surface of the plate. The apparatus can operate with electromagnetic radiation of optical and microwave frequencies.
Inventors
- 👤 E Ash
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:47
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/55; G01N22/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
109 words
Apparatus for examining physical characteristics of the surface of an object comprising a plate containing an aperture, mounting means for the object to be examined so arranged that, in use, the object is supported with the surface to be examined adjacent to said plate and confronting said aperture, means for directing electromagnetic radiation on to said surface of the object and said plate, and means for detecting said electromagnetic radiation reflected back through said aperture and from the surface of the plate surrounding said aperture, the arrangement being such that, in use, radiation reflected from the said object has a characteristic distinguishing it from radiation reflected from said plate.
Claim 2
Dependent Claim
109 words
Apparatus for examining physical characteristics of the surface of an object comprising a plate containing an aperture, mounting means for the object to be examined so arranged that, in use, the object is supported with the surface to be examined adjacent to said plate and confronting said aperture, means for directing electromagnetic radiation on to said surface of the object and said plate, and means for detecting said electromagnetic radiation reflected back through said aperture and from the surface of the plate surrounding said aperture, the arrangement being such that, in use, radiation reflected from the said object has a characteristic distinguishing it from radiation reflected from said plate.
Claim 3
Dependent Claim
42 words
Apparatus as claimed in claim 1 in which the beam of electromagnetic radiation is polarised and a polariser is disposed in front of the detecting means and oriented to reject radiation polarised in the same direction as said beam of electromagentic radiation.
Claim 4
Dependent Claim
33 words
Apparatus as claimed in claim 1 in which the means for directing a beam of electromagnetic radiation on to the aperture includes a microwave oscillator whereby said reflected electromagnetic radiation comprises microwave radiation.
Claim 5
Dependent Claim
48 words
Apparatus as claimed in claim 3, including a hybrid T having a first arm connected to the oscillator, a second arm closed by said plate, a third arm opposite said second arm closed by an adjustable reflector and a fourth arm connected to said means for detecting radiation.
Claim 6
Dependent Claim
114 words
Apparatus for examining the surface of an object, comprising a plate containing an aperture, mounting means for the object to be examined so arranged that, in use, the object is supported with the surface to be examined adjacent to said plate and confronting said aperture, means for directing a beam of electromagnetic radiation on to said aperture from the side of the plate remote from the object, and means for detecting radiation reflected back through said aperture and from the surface of the plate surrounding said aperture, the mounting means including means for vibrating the object relative to the plate whereby radiation reflected from said object is modulated with the frequency of said vibrations.
Claim 7
Dependent Claim
114 words
Apparatus for examining the surface of an object, comprising a plate containing an aperture, mounting means for the object to be examined so arranged that, in use, the object is supported with the surface to be examined adjacent to said plate and confronting said aperture, means for directing a beam of electromagnetic radiation on to said aperture from the side of the plate remote from the object, and means for detecting radiation reflected back through said aperture and from the surface of the plate surrounding said aperture, the mounting means including means for vibrating the object relative to the plate whereby radiation reflected from said object is modulated with the frequency of said vibrations.
Claim 8
Dependent Claim
53 words
Apparatus as claimed in claim 5 including an open resonator located on the side of the plate remote from the mounting means and so disposed relative to the surface to be examined that, in use, a stable resonant mode is obtained, said resonator having an aperture aligned with said beam of electromagnetic radiation.
Claim 9
Dependent Claim
28 words
Apparatus as claimed in claim 5 in which said means for directing a beam of electromagnetic radiation on to the aperture includes a source of optical frequency radiation.
Claim 10
Dependent Claim
17 words
Apparatus as claimed in claim 7, in which said source of optical frequency radiation comprises a laser.
References Cited (Backward Citations)
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US3504983A
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US3497703A
Cited
US3602596A
Cited
US3589815A
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US3591291A
Cited
US3715165A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |