Patents by Inventor Christopher Mark Welbourn

Christopher Mark Welbourn has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Examining a diamond
    Patent number: 6014208
    Abstract: In order to test whether a diamond has had a layer of synthetic diamond deposited thereon, it is irradiated with high energy ultraviolet radiation to cause emission of luminescence, the luminescence intensity produced by different zones of the diamond being measured and compared. In one embodiment an integrating enclosure (15) is used and the diamond (13) is mounted on a rotatable mount (14).
    Type: Grant
    Filed: March 27, 1998
    Date of Patent: January 11, 2000
    Assignee: Gersan Establishment
    Inventors: Christopher Mark Welbourn, Martin Phillip Smith, James Gordon Charters Smith, Paul Martyn Spear, Philip Maurice Martineau, Martin Cooper
  • Distinguishing natural from synthetic diamonds
    Patent number: 5883389
    Abstract: In order to provide a method of distinguishing natural from synthetic diamond which does not involve costly equipment or long periods to make a measurement, a diamond is irradiated with ultraviolet radiation which is preponderantly of wavelength 225 nm or less, such that substantially only the surface region of the diamond is irradiated. By observing the pattern or luminescence and/or phosphorescence produced by the diamond, an observer can identify the diamond as a natural or synthetic diamond.
    Type: Grant
    Filed: May 29, 1996
    Date of Patent: March 16, 1999
    Inventors: Paul Martyn Spear, Christopher Mark Welbourn
  • Examining a diamond
    Patent number: 5880504
    Abstract: In order to test whether a diamond has had a layer of synthetic diamond deposited thereon, the surface area of the natural part of the stone is measured by measuring the radiant-flux density of radiation substantially of wavelength 230 nm to 320 nm in an integrating sphere containing the diamond. This is compared to the total surface area of the diamond.
    Type: Grant
    Filed: June 6, 1997
    Date of Patent: March 9, 1999
    Assignee: Gersan Establishment
    Inventors: Martin Phillip Smith, James Gordon Charters Smith, Martin Cooper, Christopher Mark Welbourn, Philip Maurice Martineau
  • Method and apparatus for examining an object
    Patent number: 5835200
    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.
    Type: Grant
    Filed: February 3, 1997
    Date of Patent: November 10, 1998
    Assignee: Gersan Establishment
    Inventors: Martin Phillip Smith, Robin Wynclyffe Smith, Christopher Mark Welbourn