US 2022/0178835 A1 · SYSTEMS AND METHODS FOR SPECTROSCOPIC ANALYSES OF DIAMONDS

Abstract

The present invention relates to a spectroscopic analysis apparatus (10) for distinguishing between colorless gems, comprising: a sample holder (32) to retain a gem (13) in an analysis position exposing a first side of the gem and a second side thereof, opposite to the first side; a first light source (12) configured to emit a first primary beam (14) at an excitation wavelength between 600 nm and 680 nm directed towards the analysis position to impact on the first side of the gem, when it is positioned in the sample holder, and to generate emission or diffusion of light; a second light source (31) configured to emit a second primary beam (14′) comprising ultraviolet light (UV), the second primary beam being directed towards the analysis position to impact on the first side of the gem; an optical focusing system (30) to focus the light emitted or diffused by the first side of the gem in a secondary optical beam (15); a spectral dispersion device (22) arranged to collect the secondary optical beam (15) downstream of the optical focusing system (30) and configured to spatially disperse the secondary optical beam (15); a first photodetector device (24) arranged to collect the light dispersed by the spectral dispersion device (22) and configured to output a distribution of spectral intensity as a function of the emission wavelength in a range of emission wavelengths included within the range between 660 nm and 900 nm; a second photodetector device (37) to detect visible light arranged in front of a second side of the gem, so as to collect light transmitted through the gem; a film of fluorescent material (39) to UV light able to be positioned in a first position between the second side of the gem and the second photodetector device (37) to detect fluorescence and in a second position external to the field of view of the second photodetector device (37); a central processing unit (36) connected to the first and to the second photodetector device (24, 37), to the first (12) and to the second light source (31), the central processing unit (36) being configured to: activate the first light source (12) to emit the first primary beam (14) towards the analysis position; acquire the distribution of spectral intensity from the first photodetector device (24) as a function of the emission wavelength; analyze (102) the distribution of spectral intensity to determine the presence or the absence of a Raman intensity peak at a wavelength corresponding to a difference in wave numbers between the diffusion light and the excitation wavelength, equal to 1332 cm−1; if, as a result of the analysis, a Raman intensity peak is determined to be absent (103), establish that the gem is not a diamond and output an indication that the gem is not a diamond; if, as a result of the analysis, a Raman intensity peak is determined to be present (104), establish that the gem is a diamond and proceed with verifying (116) whether the tested diamond absorbs UV light, wherein verifying the UV light absorption comprises deactivating the first light source (12) and activating the second light source (31) to emit the second primary beam (14′) towards the analysis position; positioning the film of fluorescent material (39) in the first position so that the second primary beam transmitted through the gem interacts with the film of fluorescent material to generate visible light detected by the second photodetector device (37); acquiring from the second photodetector device (37) a fluorescence signal representative of the UV light transmitted through the gem; analyzing the fluorescence signal to determine whether the fluorescence intensity is greater or smaller than or equal to a predetermined transmission threshold value (IT)v (112); if, as a result of the analysis (112), the fluorescence intensity is determined to be smaller than or equal to the threshold value (IT)v, establishing that the gem is a type I natural diamond and outputting an indication that the gem is a natural diamond; if, as a result of the analysis (112), the fluorescence intensity is determined to be greater than the threshold value (IT)v, establishing that the gem is a type II diamond and outputting an indication that the gem is a type II diamond.

Claims9

Dependent claims

A spectroscopic analysis apparatus for distinguishing between colorless gems, the apparatus comprising:

a sample holder to retain a gem in an analysis position exposing a first side of the gem and a second side thereof, opposite to the first side;
a first light source configured to emit a first primary beam at an excitation wavelength between 600 nanometers (nm) and 680 nm directed towards the analysis position to impact on the first side of the gem, when it is positioned in the sample holder, and to generate emission or diffusion of light;
a second light source configured to emit a second primary beam comprising ultraviolet (UV) light, the second primary beam being directed towards the analysis position to impact on the first side of the gem;
an optical focusing system to focus the light emitted or diffused by the first side of the gem in a secondary optical beam;
a spectral dispersion device arranged to collect the secondary optical beam downstream of the optical focusing system and configured to spatially disperse the secondary optical beam;
a first photodetector device arranged to collect the light dispersed by the spectral dispersion device and configured to output a distribution of spectral intensity as a function of the emission wavelength in a range of emission wavelengths included within the range between 660 nm and 900 nm;
a second photodetector device to detect visible light arranged in front of a second side of the gem, so as to collect light transmitted through the gem;
a film of fluorescent material to UV light able to be positioned in a first position between the second side of the gem and the second photodetector device to detect fluorescence and in a second position external to the field of view of the second photodetector device;
a central processing unit connected to the first and to the second photodetector device to the first and to the second light source, the central processing unit being configured to:
activate the first light source to emit the first primary beam towards the analysis position;
acquiring from the first photodetector device the distribution of spectral intensity as a function of the emission wavelength;
analyze the distribution of spectral intensity to determine the presence or the absence of a Raman intensity peak at a wavelength corresponding to a difference in wave numbers between the diffusion light and the excitation wavelength, equal to 1332 cm−1;
if, as a result of the analysis, a Raman intensity peak is determined to be absent, establish that the gem is not a diamond and output an indication that the gem is not a diamond;
if, as a result of the analysis, a Raman intensity peak is determined to be present, establish that the gem is a diamond and proceed with verifying whether the tested diamond absorbs UV light, wherein verifying the UV light absorption comprises
deactivating the first light source and activating the second light source to emit the second primary beam towards the analysis position;
positioning the film of fluorescent material in the first position so that the second primary beam transmitted through the gem interacts with the film of fluorescent material to generate visible light detected by the second photodetector device;
acquiring from the second photodetector device a fluorescence signal representative of the UV light transmitted through the gem;
analyzing the fluorescence signal to determine whether the fluorescence intensity is greater or smaller than or equal to a predetermined transmission threshold value;
if, as a result of the analysis, the fluorescence intensity is determined to be smaller than or equal to the threshold value, establishing that the gem is a type I natural diamond and outputting an indication that the gem is a natural diamond;
if, as a result of the analysis, the fluorescence intensity is determined to be greater than the threshold value, establishing that the gem is a type II diamond and outputting an indication that the gem is a type II diamond.

17 more elements

A spectroscopic analysis method for distinguishing between colorless gems, the method comprising:

positioning a gem in an analysis position exposing a first side of the gem and a second side thereof, opposite to the first side;
directing a first primary beam at an excitation wavelength between 600 nanometers (nm) and 680 nm towards the analysis position to impact on a first side of the gem and generating emission or diffusion of light, wherein the first primary beam is emitted by a first light source;
focusing and spatially dispersing the light emitted or diffused by the first side of the gem;
detecting the spatially dispersed light and producing a distribution of spectral intensity as a function of the emission wavelength using a first photodetector device in a range of emission wavelengths included within the range between 660 nm and 900 nm;
acquiring from the first photodetector device the distribution of spectral intensity as a function of the emission wavelength;
analyzing the distribution of spectral intensity to determine the presence or the absence of a Raman intensity peak at a wavelength corresponding to a difference in wave numbers between the diffusion light and the excitation wavelength, equal to 1332 cm−1;
if, as a result of the analysis, a Raman intensity peak is determined to be absent, establish that the gem is not a diamond and output an indication that the gem is not a diamond;
if, as a result of the analysis, a Raman intensity peak is determined to be present, establishing that the gem is a diamond and proceeding with verifying whether the tested diamond absorbs ultraviolet (UV) light, wherein verifying the UV absorption comprises
deactivating the first light source and activating a second light source configured to emit a second primary beam comprising light at UV wavelength towards the analysis position to impact on the first side of the gem;
positioning a film of fluorescent material at the second side of the gem so that the second primary beam, transmitted through the gem, interacts with the film of fluorescent material to generate visible light;
acquiring, using a second photodetector device, visible light emitted by the film of fluorescent material to output a fluorescence signal representative of the UV light transmitted through the gem and analyzing said fluorescence signal to determine whether the fluorescence intensity is greater or smaller than or equal to a predetermined transmission threshold value;
if, as a result of the analysis, the fluorescence intensity is determined to be smaller than or equal to the threshold value, establishing that the gem is a type I natural diamond and outputting an indication that the gem is a natural diamond;
if, as a result of the analysis, the transmitted UV radiation intensity is determined to be greater than the threshold value, establishing that the gem is a type II diamond and outputting an indication that the gem is a type II diamond.

10 more elements

Dependencies are inferred from the claim text.

Systems and methods for spectroscopic analyses of diamonds

Life of this patent

Systems and methods for spectroscopic analyses of diamonds

Life of this patent

Abstract

Claims9