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US5835200A Expired / Lapsed US ⏱️ 0.0 years remaining

Method and apparatus for examining an object

Assignee: Gersan Ets
•
Filing: 1997-02-03
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Granted: 1998-11-10
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Expires: 2017-02-03
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Abstract

Abstract In order to examine a gemstone, the stone is irradiated and observed though a filter (5) at a first wavelength which is characteristic of a first class of gemstones. The filter can be rocked from a setting normal to the optical axis to transmit radiation of at least one reference wavelength. The intensities of radiation transmitted at first and reference wavelengths are observed and compared, to classify the gemstone as belonging to the first class or not. In order to detect whether the gemstone is a diamond or diamond simulant, the first wavelength comprises raman emission characteristic of diamond. In order to detect whether the gemstone is definitely natural or not definitely natural, the gemstone is classified as definitely natural if there is a maximum of absorption of radiation at 415.5 nm.

Inventors

  • 👤 Martin Phillip Smith
  • 👤 Robin Wynclyffe Smith
  • 👤 Christopher Mark Welbourn

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-07 12:06
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/87

Claims Analysis

Total Claims: 35
Claim 1
Independent Claim 179 words
A method of classifying a diamond as belonging to a first class consisting of definitely natural diamonds or to a class comprising diamonds which may or may not be natural, comprising: irradiating the diamond; observing the diamond through a narrow band pass filter that passes radiation of a wavelength corresponding substantially to a characteristic wavelength peak in the absorption spectrum of the first class of diamond; the diamond being observed by cycling the wavelength passed by the filter a number of times through each wavelength of a set of wavelengths including the characteristic wavelength peak and at least two reference wavelengths in the region of the characteristic wavelength peak; making a plurality of measurements of the intensity of radiation passing through the filter at each of the wavelengths of said set and storing each of the measurements; determining whether the characteristic wavelength peak is present or absent in the absorption spectrum of the diamond on the basis of the measurements and thereby classifying the diamond as belonging to the first class or not on the basis of the measurements.
Claim 2
Independent Claim 179 words
A method of classifying a diamond as belonging to a first class consisting of definitely natural diamonds or to a class comprising diamonds which may or may not be natural, comprising: irradiating the diamond; observing the diamond through a narrow band pass filter that passes radiation of a wavelength corresponding substantially to a characteristic wavelength peak in the absorption spectrum of the first class of diamond; the diamond being observed by cycling the wavelength passed by the filter a number of times through each wavelength of a set of wavelengths including the characteristic wavelength peak and at least two reference wavelengths in the region of the characteristic wavelength peak; making a plurality of measurements of the intensity of radiation passing through the filter at each of the wavelengths of said set and storing each of the measurements; determining whether the characteristic wavelength peak is present or absent in the absorption spectrum of the diamond on the basis of the measurements and thereby classifying the diamond as belonging to the first class or not on the basis of the measurements.
Claim 3
Dependent Claim 28 words
The method of claim 1, wherein the filter is tilted about an axis normal to its optical axis to alter the band of radiation passed by the filter.
Claim 4
Dependent Claim 21 words
The method of claim 2, wherein the filter is tilted to and from between a first position and a second position.
Claim 5
Dependent Claim 34 words
The method of claim 1, wherein the object is irradiated with radiation of a plurality of wavelengths and the intensity of radiation transmitted by the object is observed through the narrow band pass filter.
Claim 6
Dependent Claim 21 words
The method of claim 1, wherein the reference wavelengths and the characteristic wavelength are within approximately 15 nm of each other.
Claim 7
Dependent Claim 64 words
The method of claim 4, wherein the intensity of radiation transmitted by the object at the first wavelength and at the reference wavelengths is observed, and wherein the reference wavelengths lie outside but adjacent the absorption peak corresponding to the characteristic wavelength in the absorption spectrum of an object of the particular class to show any significant difference within a narrow range of wavelengths.
Claim 8
Dependent Claim 31 words
The method of claim 4, wherein the method is for examining diamonds, the characteristic wavelength being substantially equal to 415.5 nm, and the particular class of object comprising type IaAB diamonds.
Claim 9
Dependent Claim 17 words
The method of claim 7, wherein one of the reference wavelengths is substantially equal to 410 nm.
Claim 10
Dependent Claim 21 words
The method of claim 9, wherein the reference wavelengths and the characteristic wavelength are within approximately 15 nm of each other.
Claim 11
Dependent Claim 41 words
The method of claim 1, further comprising using the observation at a first reference wavelength to correct the observations at the characteristic wavelength and at least one second reference wavelength to correct for spectral variations in the radiation irradiating the object.
Claim 12
Dependent Claim 25 words
The method of claim 1, wherein the object is observed at a large number of wavelengths, including the first wavelength and the two reference wavelengths.
Claim 13
Dependent Claim 56 words
A method of claim 1, wherein the measurements of the radiation transmitted at each of the wavelengths of the set are combined mathematically to provides a combined signal substantially independent of the size of the object, the object being classified as belonging to the particular class of objects or not in response to said combined signal.
Claim 14
Dependent Claim 14 words
The method of claim 12, wherein the measurements are combined by a statistical technique.
Claim 15
Dependent Claim 182 words
Apparatus for classifying a diamond as belonging to a first class consisting of definitely natural diamonds or to a class comprising diamonds which may or may not be natural, comprising: means for irradiating the diamond; a filter which passes radiation at a wavelength corresponding substantially to a characteristic wavelength peak in the absorption spectrum of the first class of diamond; means for tilting the filter to cyclically alter the band of radiation passed by the filter through each of a set of wavelengths including the characteristic wavelength peak and at least two reference wavelengths different from the characteristic wavelength peak in the region of the characteristic wavelength peak; means for generating signals dependent upon the intensity of radiation passing through the filter at each of the wavelengths of said set; means for storing each of said signals; and means for determining whether the characteristic wavelength peak is present or absent in the absorption spectrum of the diamond on the basis of the signals and thereby classifying the diamond as belonging to the first class or not on the basis of the signals.
Claim 16
Dependent Claim 182 words
Apparatus for classifying a diamond as belonging to a first class consisting of definitely natural diamonds or to a class comprising diamonds which may or may not be natural, comprising: means for irradiating the diamond; a filter which passes radiation at a wavelength corresponding substantially to a characteristic wavelength peak in the absorption spectrum of the first class of diamond; means for tilting the filter to cyclically alter the band of radiation passed by the filter through each of a set of wavelengths including the characteristic wavelength peak and at least two reference wavelengths different from the characteristic wavelength peak in the region of the characteristic wavelength peak; means for generating signals dependent upon the intensity of radiation passing through the filter at each of the wavelengths of said set; means for storing each of said signals; and means for determining whether the characteristic wavelength peak is present or absent in the absorption spectrum of the diamond on the basis of the signals and thereby classifying the diamond as belonging to the first class or not on the basis of the signals.
Claim 17
Dependent Claim 70 words
The apparatus of claim 14, wherein the means for altering the wavelength passed by the filter is for placing the filter in a plurality of positions and the signal generating means is set up to generate a signal dependent upon the intensity of light transmitted by the object at each of said plurality of positions of the filter, said plurality of positions including said first and said two further positions.
Claim 18
Dependent Claim 73 words
The apparatus of claim 15, wherein the means for altering the wavelength passed by the filter is for placing the filter in each of said plurality of positions a number of times, the signal generating means being set upon to provide a signal dependent upon the intensity of radiation passing through the filter each time it is in each of said plurality of positions, the resulting signals being input to the computing means.
Claim 19
Dependent Claim 18 words
The apparatus of claim 14, wherein the filter is tiltable about an axis normal to its optical axis.
Claim 20
Dependent Claim 47 words
The apparatus of claim 14, wherein the irradiating means is for irradiating the object with radiation of a plurality of wavelengths and the apparatus is set up so that signals dependent upon the intensity of radiation transmitted by the object are provided by said signal generating means.
Claim 21
Dependent Claim 21 words
The apparatus of claim 14, wherein said reference wavelengths and said characteristic wavelength are within approximately 15 nm of each other.
Claim 22
Dependent Claim 43 words
The apparatus of claim 14, wherein the reference wavelengths lie outside but adjacent the absorption peak corresponding to the characteristic wavelength in the absorption spectrum of an object of the particular class to show any significant difference within a narrow range of wavelengths.
Claim 23
Dependent Claim 30 words
The apparatus of claim 14, being set up to examine diamonds, the characteristic wavelength being substantially equal to 415.5 nm, and the particular class of object comprising type IaAB diamonds.
Claim 24
Dependent Claim 17 words
The apparatus of claim 21, wherein one of the reference wavelength is substantially equal to 410 nm.
Claim 25
Dependent Claim 21 words
The apparatus of claim 22, wherein said reference wavelengths and said characteristic wavelength are within approximately 15 nm of each other.
Claim 26
Dependent Claim 61 words
The apparatus of claim 14, further comprising computing means which is set up to combine the signals dependent upon the intensity of radiation passing through the filter mathematically, to provide a combined signal substantially independent of the size of the object, the object being classified as belonging to said first class of objects or not in response to said combined signal.
Claim 27
Dependent Claim 17 words
The apparatus of claim 24, wherein the computing means is set up to combine the signals statistically.
Claim 28
Independent Claim 167 words
A method of classifying a diamond as belonging to a first class consisting of definitely natural diamonds or to a class comprising diamonds which may or may not be natural, comprising: irradiating a diamond with radiation of a plurality of wavelengths; observing through a narrow band pass filter radiation transmitted by the diamond, and altering the band passed by the filter, wherein radiation transmitted is observed at a wavelength corresponding substantially to a characteristic wavelength peak in the absorption spectrum of the first class of diamond and at least one reference wavelength in the region of the characteristic wavelength peak; the diamond being observed by measuring the intensity of radiation passing through the narrow band pass filter, making a plurality of measurements of the intensity of radiation transmitted by the object at said characteristic and reference wavelength and storing said measurements over time; and classifying the diamond as belonging to the first class or not in response to a pattern determined from the measurements stored over time.
Claim 29
Independent Claim 167 words
A method of classifying a diamond as belonging to a first class consisting of definitely natural diamonds or to a class comprising diamonds which may or may not be natural, comprising: irradiating a diamond with radiation of a plurality of wavelengths; observing through a narrow band pass filter radiation transmitted by the diamond, and altering the band passed by the filter, wherein radiation transmitted is observed at a wavelength corresponding substantially to a characteristic wavelength peak in the absorption spectrum of the first class of diamond and at least one reference wavelength in the region of the characteristic wavelength peak; the diamond being observed by measuring the intensity of radiation passing through the narrow band pass filter, making a plurality of measurements of the intensity of radiation transmitted by the object at said characteristic and reference wavelength and storing said measurements over time; and classifying the diamond as belonging to the first class or not in response to a pattern determined from the measurements stored over time.
Claim 30
Dependent Claim 229 words
Apparatus for classifying a diamond as belonging to a first class consisting of definitely natural diamonds or to a class comprising diamonds which may or may not be natural, comprising: means for irradiating the diamond with radiation of a plurality of wavelengths; means for generating intensity signals dependent upon the intensity of light transmitted by the diamond at a wavelength corresponding substantially to a characteristic wavelength peak in the absorption spectrum of the first class of diamond and at least one reference wavelength in the region of the characteristic wavelength peak, comprising a narrow band pass filter and means for altering the wavelength passed by the filter, wherein the narrow band pass filter passes radiation of the characteristic wavelength peak in a first position and radiation of the reference wavelength in a second position, the means for altering the wavelength passed by the filter cycling the filter repeatedly between said first position and second position, so that a signal dependent upon the intensity of radiation transmitted by the filter is given each time the filter is in said first or second position; and computing means for storing each of the signals and for combining the signals to provide a combined signal substantially independent of the size of the diamond and for classifying the diamond as belonging to the first class or not on the basis of the combined signal.
Claim 31
Dependent Claim 229 words
Apparatus for classifying a diamond as belonging to a first class consisting of definitely natural diamonds or to a class comprising diamonds which may or may not be natural, comprising: means for irradiating the diamond with radiation of a plurality of wavelengths; means for generating intensity signals dependent upon the intensity of light transmitted by the diamond at a wavelength corresponding substantially to a characteristic wavelength peak in the absorption spectrum of the first class of diamond and at least one reference wavelength in the region of the characteristic wavelength peak, comprising a narrow band pass filter and means for altering the wavelength passed by the filter, wherein the narrow band pass filter passes radiation of the characteristic wavelength peak in a first position and radiation of the reference wavelength in a second position, the means for altering the wavelength passed by the filter cycling the filter repeatedly between said first position and second position, so that a signal dependent upon the intensity of radiation transmitted by the filter is given each time the filter is in said first or second position; and computing means for storing each of the signals and for combining the signals to provide a combined signal substantially independent of the size of the diamond and for classifying the diamond as belonging to the first class or not on the basis of the combined signal.
Claim 32
Dependent Claim 173 words
Apparatus for classifying a diamond as belonging to a first class consisting of definitely natural diamonds or to a class comprising diamonds which may or may not be natural, comprising: an irradiation source for irradiating the diamond; a filter which passes radiation at a wavelength substantially corresponding to a characteristic wavelength peak in the absorption spectrum of the first class of diamond; a drive for tilting the filter to cyclically alter the band of radiation passed by the filter through each of a set of wavelengths including the characteristic wavelength peak and at least two reference wavelengths in the region of the characteristic wavelength peak; and a sensor for generating signals dependent upon the intensity of radiation passing through the filter at each of the wavelengths of said set, and a computer for storing each of said signals each time the filter is cycled through said set and for classifying the diamond as belonging to the first class or not on the basis of a pattern determined from the signals stored over time.
Claim 33
Dependent Claim 173 words
Apparatus for classifying a diamond as belonging to a first class consisting of definitely natural diamonds or to a class comprising diamonds which may or may not be natural, comprising: an irradiation source for irradiating the diamond; a filter which passes radiation at a wavelength substantially corresponding to a characteristic wavelength peak in the absorption spectrum of the first class of diamond; a drive for tilting the filter to cyclically alter the band of radiation passed by the filter through each of a set of wavelengths including the characteristic wavelength peak and at least two reference wavelengths in the region of the characteristic wavelength peak; and a sensor for generating signals dependent upon the intensity of radiation passing through the filter at each of the wavelengths of said set, and a computer for storing each of said signals each time the filter is cycled through said set and for classifying the diamond as belonging to the first class or not on the basis of a pattern determined from the signals stored over time.
Claim 34
Independent Claim 171 words
A method of classifying a diamond as belonging to a first class consisting of definitely natural diamonds or to a class comprising diamonds which may or may not be natural, comprising: irradiating the diamond; observing the diamond through a narrow band pass filter that passes radiation of a wavelength corresponding substantially to a characteristic wavelength peak in the absorption spectrum of the first class of diamond; the diamond being observed by tilting the filter to cycle the wavelength passed by the filter a number of times through each wavelength of a set of wavelengths including the characteristic wavelength peak and at least two reference wavelengths in the region of the characteristic wavelength peak; making a measurement of the intensity of the radiation passing through the filter at each of the wavelengths of said set each time the filter is cycled through said set; and storing said measurements; the measurements at the wavelengths of said set being used to classify the object as belonging to the first class of diamond or not.
Claim 35
Independent Claim 171 words
A method of classifying a diamond as belonging to a first class consisting of definitely natural diamonds or to a class comprising diamonds which may or may not be natural, comprising: irradiating the diamond; observing the diamond through a narrow band pass filter that passes radiation of a wavelength corresponding substantially to a characteristic wavelength peak in the absorption spectrum of the first class of diamond; the diamond being observed by tilting the filter to cycle the wavelength passed by the filter a number of times through each wavelength of a set of wavelengths including the characteristic wavelength peak and at least two reference wavelengths in the region of the characteristic wavelength peak; making a measurement of the intensity of the radiation passing through the filter at each of the wavelengths of said set each time the filter is cycled through said set; and storing said measurements; the measurements at the wavelengths of said set being used to classify the object as belonging to the first class of diamond or not.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2001-11-09 2002-05-11 2002-11-10 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2005-11-09 2006-05-11 2006-11-10 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2009-11-09 2010-05-11 2010-11-10 $7700.00 Window Closed / Lapsed

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