WO2018150221A1 - Dispositif d'identification de diamant - Google Patents

Dispositif d'identification de diamant Download PDF

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Publication number
WO2018150221A1
WO2018150221A1 PCT/IB2017/050803 IB2017050803W WO2018150221A1 WO 2018150221 A1 WO2018150221 A1 WO 2018150221A1 IB 2017050803 W IB2017050803 W IB 2017050803W WO 2018150221 A1 WO2018150221 A1 WO 2018150221A1
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WO
WIPO (PCT)
Prior art keywords
diamond
light source
detector
light
testing
Prior art date
Application number
PCT/IB2017/050803
Other languages
English (en)
Inventor
Kui Lim Tam
Original Assignee
Jubilee Diamond Instrument (S) Pte.Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jubilee Diamond Instrument (S) Pte.Ltd. filed Critical Jubilee Diamond Instrument (S) Pte.Ltd.
Priority to PCT/IB2017/050803 priority Critical patent/WO2018150221A1/fr
Publication of WO2018150221A1 publication Critical patent/WO2018150221A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/87—Investigating jewels
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/33—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using ultraviolet light

Definitions

  • a gemstone is a diamond or a diamond simulant (for example a synthetic moissanite or a cubic zirconia) .
  • Gemologists therefore rely on gemstone identification devices to identify the type of the gemstone.
  • Some gemstone identification devices work on the principle of measuring the reflectivity of the gemstone. Each type of gemstone would reflect light in different amounts. Visible or infrared light is shown onto the gemstone and the amount of reflected light is measured by a photodetector or photodiode . The measured light is cross- referenced to a table or chart and the type of the gemstone is determined.
  • the gemologist would then usually want to know if the diamon is natural or synthetic. Gemologists would usually use a detector device to shine ultraviolet light on the diamond.
  • These detector devices work by measuring the permissibility of ultraviolet light through the diamond. If the diamond doe not permit any ultraviolet light through, the diamond is inferred to be natural. If the diamond permits ultraviolet light through, there is a high possibility that the diamond is synthetic.
  • a UV light detector can be used to detect a broad absorption minimum below 370 nm. Thereby, it can be checked whether the diamond is possibly a synthetic diamond or a diamond with a high pressure high temperature (HPHT) treatment .
  • HPHT high pressure high temperature
  • the current specification discloses a diamond testing device with a casing, which comprises a base portion and a central column.
  • the casing can be made of a plastic material .
  • a rod-shaped vertically adjustable detector holder is arranged such that it is vertically movable in the casing.
  • the detector holder comprises a UV light detector, which is arranged in the detector holder.
  • a detector surface of the UV light detector is arranged above a downward facing opening of the detector holder.
  • the casing comprises a testing platform for sup- porting a specimen with an opening.
  • the open- ing can be circular and it can be provided in a central posi- tion of the testing platform.
  • a UV light source is provided below the opening such that the UV light is emitted vertically upwards through the opening of the testing platform.
  • the UV light source, the opening and the UV light detector are vertically aligned to each other, such that there is a straight-line connection between an emitting surface of the UV light source, the opening and a detector surface of the UV light detector.
  • a light source is arranged to emit light at a predetermined angle towards the opening or towards an observation position immediately above the opening.
  • a light detector is arranged to detect an amount or an intensity of light from the light source.
  • the light source and the light detector photodiode which are provided below the testing surface and below the opening in a base portion of the casing, are directed towards the opening and inclined towards an imaginary vertical line that passes through the opening.
  • the light source can be a source of visible light, an IR light source or a light source which emits in the visible and the IR range. More specifically it can be a LED emitting light in the visible range, an IR LED or a LED emitting light in both the visible and the IR range. Similar the light detector can be a detector that is sensitive in th visible light range, the IR light range or in both the visible and the IR range.
  • the IR light source can be provided as an IR LED and the IR light detector can be provided as an IR photodiode.
  • the light source emits light within the wavelength range between 760 nanome- tres and 1 mm. In one particular embodiment, the light source emits 90% of the intensity between 760 nanometres and 1 mm.
  • the inclination of the IR light detector and the IR light source can be between 30 degrees and 60 degrees.
  • the inclination is understood as the inclination of the vertical to the detector surface or light emitting surface, respectively.
  • the inclination of the IR light detector and the IR light source can be different but preferentially is the same or the same within a deviation of 2 degrees .
  • a processing module is connected to the UV light detector, the UV light source, the IR light source and the IR light detector.
  • the processing module can be provided on a printed circuit board which is arranged in the base portion of the casing.
  • the casing comprises a display module that is connected to the processing module.
  • the display module comprises a display panel that is arranged below or in an opening of the casing.
  • a user input element such as a push button, a turn button, a lever or a touch sensitive surface is provided at the casing and connected to the processing module.
  • a power supply module is connected to the processing module.
  • the IR light source can be provided as an infrared LED (light emitting diode) and the IR light detector as an IR light sensitive photo diode.
  • the IR light source, the IR light detector and the UV light source are provided in a sensor module, wherein the UV light source being arranged between the IR LED and the IR photodiode in a horizontal direction.
  • the UV light source is oriented such that the UV light is emitted vertically upwards or vertically upwards within a margin of 2 degrees .
  • the casing comprises a central column and a base portion.
  • the column which is attached to the base portion, comprises a vertical slot in which the detector holder is movable in a vertical direction.
  • the detector holder protrudes at a right angle from a front surface of the central column.
  • the diamond testing device comprises a gear mechanism for moving the detector holder in the vertical direction and a driving means, such as a turn knob or an electrical motor for actuating the gear mechanism.
  • the gear mechanism which is provided in the casing comprises a tooth wheel and a toothed rack.
  • the toothed rack is mechanically connected to the detector holder and the tooth wheel engages with the toothed rack.
  • the gear mechanism can comprise an auto-lock element, which locks the detector holder in at least a predetermined first position.
  • the locking force can be such that it can be overcome easily by a turning force of a user's hand.
  • the locking can be realized by friction or a wedging effect, for example.
  • the auto-lock element locks the detector holder in a predetermined first position and in a predetermined second position, which is above the predetermined first position.
  • the auto-lock element needs is configured such that the locking force can be overcome in two opposite direction for the first locking position and in at least one direction for the second locking position. If there is only one locking position, the locking needs to be releasable in at least one direction, such that the detector holder can be moved downwards again.
  • the auto-lock element comprises an internal ball bearing which is mechanically connected to a moving part of the gear mechanism.
  • the ball bearing can be connected to a rod or shaft that is in turn connected to turning knobs or to an electric motor.
  • the locking effect can be provided by the balls of the ball bearing dropping into pockets in a predetermined position.
  • ball bearing also includes ball bearing like elements, which comprise at least a rotatable element and balls provided within the rotatable element, wherein the balls are provided in a circular arrangement.
  • the diamond testing device comprises a resilient means such as a spring, a foam, a rubber part or gas filled piston for biasing the detector holder in a downward direction.
  • the resilient means is attached to the casing and connected to the detector holder.
  • the diamond testing device may comprise a posi tion reset button for actuating a position reset mechanism, the position reset mechanism being configured such that the detector holder is disengaged from the gear mechanism, or, more specifically, from the portion of the gear mechanism t which it is connected.
  • the tooth wheel of the move ment mechanism is provided on a carrier that is movable in horizontal direction, away from the toothed rack, and the carrier is connected to the position reset button.
  • the UV light detector can be provided as a semiconductor component, such as a photodiode, which is readily available on the market.
  • a sensitivity of the UV light detector is suitable for detecting a possible synthetic diamond and diamonds with HPHT treatment .
  • the UV light source can be provided as a semiconductor component, such as a UV light emitting LED or a small-scale UV light emitting semiconductor laser.
  • the UV light source emits at least 90% of the intensity in the wavelength range below 370 nm.
  • the IR light source may be designed such that it emits at least 70%, 80% or 90% of its intensity in the infrared range.
  • the IR range or UV range may refer to the ranges defined in the ISO standard 21348 according to which the IR range extends from 760 nm to 1 mm and the UV range extends from 100 nm to 400 nm.
  • the opening of the testing platform comprises a testing window, which essentially covers the opening and is flush with the testing surface.
  • the sensor module can be arranged on a main board that is attached or screwed to the casing.
  • the user input element comprises a testing mode select button.
  • the processor unit and the testing mode select button are configured to select between a UV testing mode, an IR testing mode and a combined UV and IR testing mode.
  • the casing can comprise a hood or cover for covering testing platform. The hood is pivotably attached to the casing by respective arms.
  • a position sensor of the casing is connected to the processing unit.
  • the processing unit is configured such that the UV light source can be activated when the hood is closed and is deactivated when the hood is open, and wherein the processing sensor determines whether the hood is open or closed based on a signal of the position sensor.
  • the diamond testing device comprises a first white light source at a first side of the opening and a second white light source at a second side of the opening, and an illumination button.
  • the first white light source and the second white light source are activated when the illumination button is pressed. Thereby, the specimen is better visible and can be positioned more easily.
  • the present specification discloses a computer implemented method for performing a UV transmission test of a specimen with the abovementioned diamond testing device.
  • a specimen is placed onto the testing platform and above the opening, and a UV testing mode is selected via a push button.
  • the UV testing mode may be a UV transmission testing mode or also a combined UV transmission and IR reflectivity testing mode.
  • the detector holder is moved to a testing position, which is a predetermined height above a testing platform for loose specimen or a clamping position in which the detector holder touches the ring for a specimen on a ring.
  • a hood of the diamond testing device is closed, and the UV light source is activated.
  • the UV light source can be activated via a pushbutton, which includes activating it by using the pushbutton to select a testing mode.
  • a signal of the UV light detector is read out and a test result is derived from the signal.
  • the test result is displayed on a display panel. If the combined UV transmission and IR reflectivity testing mode is selected, the following steps are carried out in addition:
  • the IR light source such as an IR LED
  • a signal of the IR light detector such as an IR photodiode
  • a test result from the signal and the test result is displayed on a display panel.
  • the present specification discloses a computer implemented method for performing an IR reflectivity test of a specimen with the aforementioned diamond testing device.
  • a specimen is placed onto the testing platform and above the opening, an IR testing mode is selected.
  • the IR testing mode can be an IR reflectivity testing mode or a combined IR reflectivity and UV transmission testing mode.
  • the detector holder is moved to a testing position, which in the case of a loose specimen is at a predetermined height above the testing platform and which, in the case of a specimen on a ring is a clamping position in which the ring is clamped onto the testing platform.
  • the hood of the diamond testing device is closed, the IR light source is activated, a signal of the IR light detector is read out, and a test result is derived from the signal.
  • the test result is displayed on a display panel.
  • the IR light source can be activated via a pushbut- ton, which includes activating it by using the pushbutton to select a testing mode.
  • the present specification discloses a combined UV transmission and IR or visible light reflectivity test.
  • a specimen is placed onto the testing platform and above the opening onto the testing window.
  • a combined UV transmission and light reflectivity testing mode is selected.
  • the detector holder is moved to a testing position, and a hood of the diamond testing device is closed.
  • the IR LED is activated, a signal of the IR photodiode is read out. It is determined whether the specimen is a diamond and. If it is determined that the specimen is a diamond, the UV light source is activated, and a signal of the UV light detector is read out. A test result from the respective signals and the test result is displayed on a display panel.
  • Fig. 1 shows a top front view of a diamond identification device in an open position
  • Fig. 2 shows a diagonal front view of the diamond identification device of Fig. 1 in a closed position
  • Fig. 3 shows a top front view of the diamond identification device in an open position, wherein a ring is placed in testing position and white light lamps are lit up,
  • Fig. 4 shows a cross sectional side view of the diamond identification device in the open position
  • Fig. 5 shows a cross sectional front view of the diamond device in the open position
  • Fig. 6 shows a diagonal front view of the diamond identification device with a ring in testing position
  • Fig. 7 shows a partial view of a detector portion of the diamond identification device with a ring-shaped specimen
  • Fig. 8 shows a partial view of a detector portion of the diamond identification device with a loose stone
  • Fig. 9 shows a schematic view of the detector portion and of connected processing resources and user interface
  • Fig. 10 shows a flowchart depicting the steps taken by an apparatus to determine the type of the gemstone with the diamond identification device of Fig. 1,
  • Fig. 11 shows an exemplary method to cross-reference the calculated reflectivity value with the reference data to determine the type of the gemstone.
  • Fig. 1 shows a top front view of a diamond identification device 10 in an open position.
  • the diamond identification device 10 comprises a casing 11 with a base portion 12, a central column 13 and a cover 14, which is pivotably attached to the central column 13.
  • the base portion 12 comprises two side portions 15, 16 with respective horizontal surfaces 17, 18, a testing platform 19 which is arranged between the two side portions 15, 16, and display area 20 with a display panel 8.
  • the display area 20 is arranged in front of the testing platform 19 and is slant ed downwards slightly.
  • a circular testing window 9 is arranged in the centre of the testing platform 19.
  • the right portion 16 comprises three circular push buttons 21, 22, 23 whose surfaces are flush with the horizontal surface 18 of the right portion 16.
  • the first push button 21, which is nearest to the front, is provided as an on/off button.
  • the second push button 22, which is arranged behind the first push button 21 is provided as a button for selecting a testing method.
  • the third push button 23, which is arranged behind the second push button 22, is provided as a button for activating a white light illumination.
  • a front surface 26 of the central column 13 comprises two white light lamps 24, 25, which are arranged at opposite sides of a bottom portion of the front surface 26.
  • a column shaped detector rod 27 is provided at a right angle to the front surface 26 such that it is movable in a vertical direction.
  • the detector rod 27 is centrally arranged with respect to a horizontal extension of the front surface 26.
  • the detector rod 27 extends from the front surface 26 unto approximately the frontal boundary of the circular testing window 9.
  • the front surface 26 comprises a circular position reset button 28, which is arranged above the detector rod 27 and horizontally centred.
  • the surface of the position reset button 28 is flush with the front surface 26 or slightly inwards.
  • the central column 13 comprises two knurled knobs 29, 30, which are arranged at opposite sides on respective side surfaces 31, 32 of the central column 13.
  • the knurled knobs 29, 30 are connected to a movement mechanism of the tector rod, which is shown in more detail in the cross- sectional view of Fig. 4.
  • the hood 14 is pivotably connected to an upper portion of the central column 13 over two arms 33, which are pivotably connected at opposite sides at the respective side surfaces of the central column 13.
  • Fig. 2 shows the diamond testing device 10 in a closed position, in which the hood 14 covers the front surface 26 of the central column 13, the detector rod 27 and the testing platform 19.
  • Fig. 3 shows the diamond identification device 10 in an open position.
  • the detector rod 27 is in a lower position in which a specimen on a ring 34 is clamped between the testing window and the detector rod.
  • Fig. 4 shows a cross sectional view of the diamond testing device, wherein the cross-sectional plane is oriented orthogonal to a base surface of the testing device 10 and extends from the front to the rear of the testing device 10 and is situated in the centre with respect to the lateral dimension of the testing device 10.
  • a movement mechanism 35 is provided for moving the rod-shaped specimen holder 27 up and down.
  • a first tooth wheel 36 which is connected to an axis to which the knurled knobs 29, 30 are attached, engages with a second tooth wheel 37, which is smaller than the first tooth wheel 36.
  • the second tooth wheel 37 engages with a vertically oriented toothed rack 38 that engages with a vertically oriented upper sliding plate 39.
  • the first tooth wheel 36 and the second tooth wheel 37 are provided on a carrier 43.
  • the upper sliding plate 39 is formed in one piece with an upper portion 40 of the detector rod 27.
  • the upper sliding plate 39 is supported in a first rectangular recess at a back side of the front surface at one side and in a second rectan- gular recess of the toothed rack.
  • a lower sliding plate 41 is formed in one piece with a lower portion 42 of the detector rod 27.
  • Two springs 51 are attached to a holder 57 on each side of the detector rod 27. In the view of Fig. 4 only one of the springs 51 is shown.
  • the holder 57 is mechanically attached to the detector rod 27 such that the detector rod 27 moves together with the holder 57.
  • the springs 51 are attached to the holder 57 and to a spring support 44. The spring pulls the detector rod 27 downwards.
  • a specimen 45 is positioned such that its base surface lies on top of the testing window 9.
  • the detector rod 27 is in an upper position in which the holder abuts to a front plate 46 of the central column 13.
  • a UV light detector 47 of the detector rod is positioned above the testing window 9.
  • the UV light detector 47 comprises a UV light sensitive photodiode.
  • a detection surface of the UV light detector 47 faces downwards from the detector rod 27 towards the testing window 9.
  • a position reset of the detector rod 27 with the position reset button 28 can be implemented in various ways.
  • a ratchet mechanism which is not shown in detail in Fig. 4, holds the detector rod 27 in position against the weight of the detector rod 27 and the downward force of the spring 51.
  • the ratchet mechanism is disconnected from the detector rod 27 and the detector rod 27 is free to move upwards until it reaches an upper stop position.
  • the ratchet mechanism is connected to the tooth wheels 36, 37 and the ratchet mechanism is disconnected by moving the carrier 43 of the tooth wheels 36, 37 away from the toothed rack 38.
  • a ratchet mechanism is connected to the toothed rack 38 and is disconnected from the toothed rack 38 when the position reset button 28 is pressed.
  • the detector rod 27 is disconnected from the toothed rack 38 when the position reset button 28 is pressed.
  • the detector rod 27 can lock itself in predetermined positions.
  • the locking of the detector rod 27 can be realized with an internal ball bearing.
  • the movement mechanism can be designed such, that the detector rod 27 locks at a predetermined first position or "loose stone position 1" and at a predetermined second position or "loose stone position 2".
  • the predetermined first position corresponds to a height of 6 mm
  • the predetermined second position corresponds to a height of 12 mm, wherein the height is measured between the testing platform 19 and the lower surface of the detector in the detector rod 27.
  • the detector rod 27 In order to test for a loose stone with height of less than a first height, in particular of less than 6 mm, the detector rod 27 is moved upwards using the knurled knob 29, 30. When the detector rod 27 reaches the predetermined first position it locks itself automatically in the predetermined first position. In order to move the detector rod 27 again, a user turns the knurled knob 29, 30 again, but with slightly more force .
  • the detec- tor rod 27 is moved further upwards using the knurled knob 29, 30.
  • the detector rod 27 reaches the predetermined second position, it locks itself automatically in that posi- tion.
  • the user rotates the knurled knob 29, 30 again, but with slightly more force to overcome the locking resistance .
  • the loose stone refers to a cut stone, in particular a gem stone, with a base surface, also referred to as table, and a pyramid like top portion, also referred to as pavilion.
  • a gem stone with this cut can be conveniently placed on the testing surface 19.
  • Fig. 4 shows component parts of the casing 11.
  • the casing 11 comprises a main board 48, which is screwed to the casing.
  • the main board 48 comprises the electronic components required for the testing.
  • An auxiliary board 56 which contains electronic components for generating display signals is provided below the display panel 8.
  • the hood 14 is supported on a base portion 49 of the casing 11 over pillars 50.
  • the arms 33 of the hood 14 are attached to a joint 55, such that the hood 14 is pivotable around the j oint 55.
  • Fig. 5 shows a further cross sectional view of the diamond testing device along the line A-A of Fig. 4.
  • Fig. 5 shows a sensor portion that is arranged between the support platform and the testing surface.
  • the sensor portion is shown in greater detail in Figures 7 and 8.
  • Fig. 6 shows a further perspective front view of the diamond testing device in which a ring with a specimen is clamped between the detector rod and the testing window.
  • the lower detector portion is also explained in the earlier patent application PCT/IB2016/054071, which is hereby incorporated by reference. Specifically, Figs. 1, 3, and 5 to 7 and the corresponding text, which relate to a sensor arrangement and Figs. 2 and 4 and the corresponding text, which relate to the use of the sensor arrangement, of the earlier application are incorporated by reference. Different from the arrangement shown in the PCT/IB2016/054071 a UV light source 106 of the diamond testing device 10 is provided between the diodes 101, 102 and a detector element 47 is provided in the detector rod 27.
  • Figures 7 and 8 show a schematic diagram of a sensor portion 104 of the diamond identification device 10.
  • the cross- sectional plane of Figs. 7 and 8 and a vertical orientation define together a coordinate system which is indicated in Figs . 7 and 8.
  • the sensor portion 104 comprises a light emitting diode 101, a detector photodiode 102 and a UV light source 106.
  • the light emitting diode 101, the detector photodiode 102 and the UV light source 106 form part of a sensor module 104.
  • the UV light source 106 can be provided by a UV light emitting photodiode or a UV light emitting sem- iconductor laser element.
  • the UV light source 106 emits ultraviolet light having a wavelength of less than 370 nanometres (nm) .
  • the UV light source 106 is arranged to emit ultraviolet light towards the testing window 9 from below.
  • the emission of UV light against the base surface, or table, of a cut gemstone which is positioned on the testing window 9 provides an effective illumination of the gem stone with UV light. In particular, it can provide a more effective illumination than an emission of light against the facets of the cut gem stone .
  • the light emitting diode 101 and the detector photodiode 102 are substantially arranged along a horizontal axis X-X.
  • the UV light source 106 lies between the light emitting diode 101 and the detector photo diode 102 in the horizontal direction X.
  • a light transmitting directing column 52 is arranged between the light emitting diode 101 and the detector photo diode 102 in the horizontal direction and aligned along the vertical direction.
  • the directing column 52 is dimensioned and arranged such that it does not obstruct the light from the light emitting diode 101 and the light reflected towards the detector photodiode 102.
  • the light emitting diode 101, the detector photodiode 102 and the UV light source 106 are provided in a supporting block 53.
  • a support platform 105 is provided on top of the supporting block 53.
  • a testing window 9 is provided in an opening 109 in a central position of the support platform 105, the testing window comprising a through hole 108.
  • the opening 109 is indicated in Figs. 7, 8 and 9.
  • the through hole 108 has a width or diameter smaller than the table size of a gemstone.
  • the through hole 108 has a width or diameter of 1 millimetre (mm) or less.
  • the dimensions of the diamond testing device can be chosen such that a loose specimen can have a maximum height of 12 mm and a ring with a specimen can have a minimum diameter of 13 mm and a maximum diameter of 35 mm.
  • the through hole 108 may be provided with a material that is transparent to light coming from the UV light source 106 while preventing dust from entering the casing 11. Further- more, the region of the testing window 9 which surrounds the through hole 108 may be provided with a coating or material which is opaque for light from the UV light source 106 while permitting light rays from the light source 101 to pass through. This then allows the UV light detector 47 to receive light rays directly from the UV light source 106, wherein these light rays travel in a straight line from the UV light source 106 to the UV light detector 47. In other words, stray light from the UV light source 106 are suppressed or prevented from reaching the UV light detector 47.
  • the light emitting diode 101 is arranged to emit light at a predetermined angle towards the observation position.
  • the light emitting diode 101 is orientated towards the observation position at a predetermined angle.
  • the predetermined angle is an acute angle between 30° to 60° .
  • the predetermined angle is substantially 45°. In operation, when the gemstone is placed at the observation position, the gemstone will reflect the light from the light emitting diode 101.
  • the detector photodiode 102 is arranged to detect the amount of visible light or infrared light emitted from the light emitting diode 101 that is reflected from the gemstone placed at the observation position.
  • the detector photo- diode 102 is arranged to be at a suitable position to detect the amount of visible light or infrared light emitted from the light emitting diode 101 that is reflected from the gem- stone placed at the observation position.
  • the visible light can refer to white light.
  • the detector photodiode 102 is arranged such that it is oriented towards the observation position.
  • the detector photodiode 102 is oriented towards the observation position at substantially the same predetermined angle as the light emitting diode 101.
  • Figs . 7 and 8 illustrate a method of investigating a gem- stone.
  • the loose gemstone is placed on the testing window 9 and above the through hole 108. Then, the detector rod is moved to its upper position by pressing the position reset button 28 or by using the knurled knobs 29, 30.
  • a base sur- face of the gemstone is placed onto the testing window 9 and the detector rod 27 is moved downwards onto the ring by using the knurled knobs 29, 30 until the ring is clamped between the detector rod 27 and the testing window 9.
  • the light emitting diode 101 In an IR testing mode, the light emitting diode 101 emits infrared light, a portion of which passes through the testing window 9, enters the gemstone from below, is reflected back from the gemstone, passes through the testing window 9 from above and is received by detector diode 102.
  • the UV light source In a UV testing mode, the UV light source emits UV light, a portion of which passes through the directing column 52, the testing window 9 and the gemstone, and is received by the UV light detector 47.
  • the UV light detector 47 in the detector rod 27 detects ultraviolet light emitted from the UV light source 106 that has passed through the gemstone at the observation position.
  • the UV light detector 47 is sub- stantially vertically aligned with the UV light source 106 and the gemstone at the observation position.
  • the light path for the IR testing mode and for the UV testing mode is schematically indicated by arrows in Figs. 7 and 8.
  • the diamond identification device 10 comprises a processor unit 110.
  • the processor unit 110 comprises a computer, a microcontroller, a microprocessor, or a processor.
  • the processor unit 110 can obtain readings from the detector photodiode 102 and the UV light detector 47.
  • the readings from the detector photodiode 102 are related to an amount of detected reflected light.
  • the readings from UV light detector 47 are related to the presence of UV light.
  • the presence of UV light may be detected by determining whether a light intensity in a predetermined frequency range surpasses a predetermined detection threshold.
  • the diamond identification device 10 comprises electrical wiring between the detector photodiode 102, the UV light detector 47 and the processor unit 110 (as shown in Fig. 9) .
  • the processor unit 110 can send the necessary instructions to activate, deactivate and regulate the light emitting diode 101 and the UV light source 106.
  • the diamond identification device 10 comprises a memory module 111 to store the readings from the detector photodiode 102 and the UV light detector 47.
  • the memory module 111 stores reference data.
  • the reference data corresponds to a plurality of gemstone types and their corresponding reflectivity values .
  • the diamond identification device 10 comprises a display module 112, which comprises the display panel 8.
  • the display panel 8 can be provided as a liquid crystal display (LCD) .
  • the processor unit 110 can display on display module 112 the results of the determination.
  • the results may comprise, among others, that the gem- stone is a diamond, that the diamond is natural, that the diamond is possibly synthetic, the diamond is a CVD diamond or contains a CVD layer.
  • the display module 112 has a touch screen capability and can accept user input.
  • the processor 110 is connected to the pushbuttons 21, 22, 23 and to any other tactile user interface, such as a touchscreen.
  • a data connection may be provided for exchanging data with an external device.
  • the diamond identification device 10 comprises a power supply module 54 to provide power to the light emitting diode 101, the UV light source 106, the detector photodiode 102, UV light detector 47, the processing unit 110, the memory module 111 and the display module 112.
  • the power module 54 may comprise rechargeable batteries and/or non- rechargeable batteries.
  • the power module 54 may comprise a transformer and a socket connector.
  • Figure 10 shows a flowchart depicting the steps taken by the diamond identification device 10 to determine the type of the gemstone and if the type of the gemstone is determined to be diamond, then determine whether the diamond is natural or possibly synthetic, in accordance with an embodiment of the invention.
  • the gemstone may be a colourless gemstone. More specifically, the gemstone may be a colourless diamond graded from D to J.
  • the device 10 accepts a user input which initiates the testing procedure.
  • This user input may be via a button on the housing of apparatus 10 that is depressed or via a touch screen input on display module 112.
  • step 202 processor unit 110 causes the light source 101 to emit visible light or infrared light towards the gemstone 301 at the observation position. This is illustrated in figure 3.
  • the photodiode 102 detects the amount of visible light or infrared light emitted from first light source 101 reflected from gemstone 301 at the observation position.
  • the processor unit 110 obtains from the photodiode 102 the amount of detected reflected light.
  • the processor unit 110 calculates a reflectivity value from the amount of detected reflected light and determines the type of the gemstone.
  • the reflectivity value represents the percentage of light being reflected.
  • a particular type of gemstone would exhibit a range of reflectivity values. For example, diamond would normally exhibit reflectivity values of between 17.1% and 19%.
  • the different types of gemstones and their corresponding reflectivity values will be stored as reference data in the memory module 111. Therefore, once the reflectivity value has been calculated, the processor unit 110 would cross-reference the calculated reflectivity value with the reference data to determine the type of gemstone .
  • An exemplary method to cross-reference the calculated reflectivity value with the reference data to determine the type of gemstone is illustrated in Figure 11.
  • processor unit 110 first checks if the reflectivity value is larger than 12.5% in step 401. If the reflectivity value is smaller than 12.5%, the processing unit 110 determines that the gemstone is a diamond simulant in a step 402. If the reflectivity value is larger than 12.5%, the processor unit 110 then determines if the reflectivity value is larger than 14.8% in a step 403. If the reflectivity value is smaller than 14.8%, the processor unit 110 determines that the gemstone is a cubic zirconia in a step 404. If the reflectivity value is larger than 14.8%, the processor unit 110 then checks to see if the reflectivity value is smaller than 17.1% in a step 405.
  • the processor unit 110 determines that the gemstone is a diamond simulant in a step 406. If the reflectivity value is larger than 17.1%, the processor unit 110 then checks to see if the reflectivity value is smaller than 19% in a step 407. If the reflectivity value is smaller than 19%, the processor unit 110 determines that the gemstone 301 is a diamond 408. If the reflectivity value is larger than 19%, the processor unit 110 determines if the reflectivity value is smaller than 23.1% in a step 409.
  • the processor unit 110 determines that the gemstone is a synthetic moissanite in a step 411. If the reflectivity value is larger than 23.1%, the processer unit 110 determines that the gemstone 301 is a diamond simulant in a step 410. Preferably, the processor unit 110 can display on the display module 112 the results of the determination.
  • the type of gemstone can be determined by the refractive index.
  • a particular type of gemstone 301 would exhibit a specific refractive index.
  • processor unit 110 determines that gemstone 301 is a diamond
  • processor unit 110 automatically causes the UV light source 106 to emit ultraviolet light towards the gemstone at the observation position.
  • the processor unit 110 displays on the display module 112 the results of the determination i.e. that the gemstone is a diamond.
  • the processor unit 110 determines whether the UV light detector 47 has detected any ultraviolet light. If the UV light detector 47 has not detected any ultraviolet light (i.e. the gemstone at the observation position did not allow any ultraviolet light to pass through and arrive at the UV light detector 47), in step 208, the processor unit 110 determines that the gemstone/diamond is natural. Preferably, the processor unit 110 displays on the display module 112 the results of the determination i.e. that the diamond is natural .
  • the processor unit 110 determines that the gemstone/diamond is possibly synthetic.
  • the reason why it may be possible to definitively determine that a diamond is synthetic via this test is due to HPHT-enhanced diamonds and a few natural A Type' diamonds.
  • HPHT-enhanced diamonds are diamonds which undergo a High Pressure High Temperature (HPHT) process. The HPHT process will change the color of the diamonds, for example from brownish diamonds to colorless diamonds, or from faint yellow diamonds to yellow fancy diamonds.
  • HPHT-enhanced diamonds allow ultraviolet light through as the HPHT-enhanced diamond is natural. Besides that, all Type II natural diamonds and very rare Type IaB natural diamonds also allow ultraviolet light to pass through. The amount of Type II natural diamonds and Type IaB is very low around 2%. For this reason, the fact that a diamond allows ultraviolet light through (such that the UV light detector 47 detects it) does not definitively conclude that the diamond is synthetic.
  • the processor unit 110 displays on display module 112 the results of the determination i.e. that the diamond is possibly synthet- ic .
  • a diamond-testing device comprising a casing, comprising
  • testing platform for supporting a specimen, the testing platform comprising an opening
  • the detector holder comprising a UV light detector
  • UV light source being provided below the opening
  • UV light source the opening and the UV light detector are vertically aligned to each other
  • the light source being arranged to emit light at a predetermined angle towards the opening, a light detector arranged to detect light from the light source ,
  • processing module being connected to the UV light detector, to the UV light source, to the light source and to the light detector,
  • the display module being connected to the processing module
  • the power supply module being connected to the processing module.
  • the diamond testing device according to item 1, wherein the light source is an IR light source and the light detector is an IR light detector.
  • the diamond testing device wherein the IR light source is an IR LED and the IR light detector is an IR photodiode.
  • the diamond testing device according to item 2 or item 3, wherein the light source emits light within the wavelength range between 760 nanometres and 1 mm.
  • the diamond testing device according to item 2 or item 3, wherein a respective orientation of the light source and of the light detector against a vertical direction is between 30 and 60 degrees .
  • the diamond testing device according to one of the items 1 to 5, wherein the light source, the light detector and the UV light source are provided in a sensor module, the UV light source being arranged between the light source and the light detector in a horizontal direction .
  • the diamond testing device according to item 6, wherein the sensor module is arranged on a main board that is attached to the casing.
  • the diamond testing device comprising a column and a base portion the column being attached to the base portion, the base portion comprising the testing surface and the column comprising a vertical slot i which the detector holder is movable in a vertical direction .
  • the diamond testing device comprising a gear mechanism for moving the detector holder in the vertical direction and a driving means for actuating the gear mechanism, the gear mecha- nism comprising a tooth wheel and a toothed rack, the toothed rack being connected to the detector holder and the tooth wheel engaging with the toothed rack.
  • the diamond testing device according to item 9, the gea mechanism comprising an auto-lock element, wherein the auto-lock element releasably locks the detector holder in at least a predetermined first position.
  • the diamond testing device according to item 10, wherein the auto-lock element locks the detector holder in a predetermined first position and in a predetermined second position, which is above the predetermined first position .
  • the diamond testing device according to item 10 or item 11, wherein the auto-lock element comprises a ball bearing which is mechanically connected to a moving part of the gear mechanism.
  • the diamond testing device according to one of the preceding items, comprising a resilient means for biasing the detector holder in a downward direction, the resilient means being attached to the casing and the resilient means being connected to the detector holder.
  • the diamond testing device according to one of the preceding items, wherein the UV light detector is provided as a semiconductor component.
  • the diamond testing device according to one of the pre- ceding items, wherein a sensitivity of the UV light de- tector is suitable for detecting a synthetic diamond and diamonds with HPHT treatment.
  • the diamond testing device according to one of the pre ceding items, wherein the UV light source is provided a semiconductor component.
  • the diamond testing device according to one of the items, wherein a testing window is provided in the open- ing, the testing window comprising a through hole.
  • the user input element comprises a testing mode select button, the processor unit and the testing mode select button being configured to select between a UV testing mode, an IR testing mode and a combined UV and IR testing mode.
  • the casing comprising a hood for covering testing platform, which is pivotably attached to the casing, and a position sensor, the position sensor being connected to the processing unit, wherein the processing unit is configured such that the UV light source can be activated when the hood is closed and is deactivated when the hood is open, and wherein the processing sensor determines whether the hood is open or closed based on a signal of the position sensor.
  • the diamond testing device comprising a first white light source at a first side of the opening and a second white light source at a second side of the opening, and an illumination button, wherein the first white light source and the second white light source are activated when the illumination button is pressed.
  • a method for performing an IR reflectivity test of a specimen with a diamond testing device comprising
  • a method for performing a combined UV transmission and light reflectivity test of a specimen with a diamond testing device comprising

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Abstract

L'invention concerne un dispositif de test de diamant possédant un boîtier comprenant un support de détecteur réglable verticalement ainsi qu'un détecteur de lumière UV, une plateforme de test comprenant une ouverture et une source de lumière UV au-dessous de l'ouverture, la source de lumière UV, l'ouverture et le détecteur étant alignés verticalement. Une source de lumière est agencée afin d'émettre de la lumière selon un angle prédéterminé vers l'ouverture et un détecteur de lumière est agencé afin de détecter la lumière provenant de la source de lumière. Le boîtier comprend en outre un module de traitement connecté au détecteur de lumière UV et à la source de lumière UV, un module d'affichage connecté au module de traitement, un élément d'entrée d'utilisateur connecté au module de traitement, et un module d'alimentation électrique connecté au module de traitement.
PCT/IB2017/050803 2017-02-14 2017-02-14 Dispositif d'identification de diamant WO2018150221A1 (fr)

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Cited By (7)

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AU2019202214B1 (en) * 2019-03-18 2020-07-23 Weihai Yaochi Crafts Co., Ltd. An identification apparatus for crystal jewelry
US10837915B2 (en) 2017-12-19 2020-11-17 Jubilee Diamond Instrument (s) PTE. LTD Gemstone testing apparatus
US10859559B1 (en) 2019-06-19 2020-12-08 Jubilee Diamond Instrument(S) Pte. Ltd. Gemstone testing apparatus
US10989667B2 (en) 2017-06-01 2021-04-27 Jubilee Diamond Instrument (S) Pte. Ltd. UV reflection tester
RU204985U1 (ru) * 2020-12-29 2021-06-22 Общество с ограниченной ответственностью «Алмазный научно-технологический центр» Устройство идентификации драгоценных камней
WO2022146197A1 (fr) * 2020-12-29 2022-07-07 Общество С Ограниченной Ответственностью "Алмазный Научно-Технологический Центр" Dispositif d'identification de pierres précieuses
US11668654B2 (en) 2017-12-19 2023-06-06 Jubilee Diamond Instrument (s) PTE. LTD Gemstone testing apparatus

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US5955735A (en) * 1997-09-29 1999-09-21 C3, Inc. Apparatus and method for positively identifying synthetic silicon carbide gemstones
US7105822B1 (en) * 2000-09-29 2006-09-12 American Gemological Laboratories, Inc. Characterization of clarity and color enhancement agents in gems
US8760758B2 (en) * 2008-10-07 2014-06-24 Gemological Institute Of America, Inc. (Gia) Reflected dark field method and apparatus
US20150219567A1 (en) * 2012-10-03 2015-08-06 Presidium Instruments Pte Ltd Gemstone tester and a method of characterising a gemstone
US20160178530A1 (en) * 2013-07-18 2016-06-23 De Beers Uk Ltd Measuring parameters of a cut gemstone

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10989667B2 (en) 2017-06-01 2021-04-27 Jubilee Diamond Instrument (S) Pte. Ltd. UV reflection tester
US10837915B2 (en) 2017-12-19 2020-11-17 Jubilee Diamond Instrument (s) PTE. LTD Gemstone testing apparatus
US11668654B2 (en) 2017-12-19 2023-06-06 Jubilee Diamond Instrument (s) PTE. LTD Gemstone testing apparatus
AU2019202214B1 (en) * 2019-03-18 2020-07-23 Weihai Yaochi Crafts Co., Ltd. An identification apparatus for crystal jewelry
US10859559B1 (en) 2019-06-19 2020-12-08 Jubilee Diamond Instrument(S) Pte. Ltd. Gemstone testing apparatus
RU204985U1 (ru) * 2020-12-29 2021-06-22 Общество с ограниченной ответственностью «Алмазный научно-технологический центр» Устройство идентификации драгоценных камней
WO2022146197A1 (fr) * 2020-12-29 2022-07-07 Общество С Ограниченной Ответственностью "Алмазный Научно-Технологический Центр" Dispositif d'identification de pierres précieuses

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