CN112034000A

CN112034000A - Gem identification device and method based on thermal conductivity and surface resistivity

Info

Publication number: CN112034000A
Application number: CN202010911888.XA
Authority: CN
Inventors: 许焱; 许济苍
Original assignee: Wenzhou Kefeng Instrument Co ltd
Current assignee: Wenzhou Kefeng Instrument Co ltd
Priority date: 2020-09-02
Filing date: 2020-09-02
Publication date: 2020-12-04

Abstract

The invention discloses a gem identification device and method based on heat conductivity and surface resistivity. The method is used for identifying and distinguishing diamonds, laboratory-cultivated diamonds, morusite, ruby, emerald, crystal, emerald, spinel, tourmaline, topaz, tanzanite, garnet, cordierite, olivine, quartz, topaz and other gems, and has high identification accuracy and wide application range.

Description

Gem identification device and method based on thermal conductivity and surface resistivity

Technical Field

The invention relates to the technical field of gem detection, in particular to a gem identification device and method based on heat conductivity and surface resistivity.

Background

As a special consumer product, the precious stone has been the symbol of achievement and wealth, right and status, love and eternal.

Natural gemstones are rare and expensive, making some people resemble a high value gemstone with a similar looking but inexpensive gemstone. With the continuous development of artificial technology, synthetic laboratory cultured diamonds appear in the market in recent years. These synthetic diamonds are very similar to natural diamonds in appearance, composition, hardness, thermal conductivity, and surface resistance, and are very annoying to the gem trading market. Therefore, there is a great need for the identification of gemstones.

In the prior patent, diamond, Mossangite (synthetic carbon silica) and imitation diamond are distinguished by the difference of thermal conductivity and electric conductivity, wherein, the thermal conductivity detection method only measures the magnitude of the thermal potential generated after the temperature of a probe thermocouple on a thermal conductivity sensor is lost, and different gemstones are distinguished according to the quantity of heat transferred. The conductivity detection method only measures the voltage on the probe which feeds back the high voltage to the thermal conductivity sensor after the high voltage passes through the gem to identify the diamond and the Mosang stone (synthetic carbon silica), the gem (diamond) with high surface resistance has low feedback voltage, and the gem (synthetic carbon silica) with low surface resistance has high feedback voltage.

The thermal conductivity, also called thermal conductivity, is given by the symbol λ, which reflects the thermal conductivity of a substance, and is defined as the amount of heat transferred by a unit thermal surface per unit time per unit temperature gradient (1K temperature decrease within 1m length), and is calculated by the formula: e/t ═ λ a (θ 2- θ 1)/L; e is the energy transferred over time t, a is the cross-sectional area, L is the length, and θ 2 and θ 1 are the temperatures of the two cross-sections, respectively, representing the temperature gradient. The length L of the probes on the thermal conductivity and conductivity sensor is the same in the two patents, the heat conduction sectional area A is the same, and a formula is derived: and λ ═ E/t (θ 2- θ 1), and the basic principle is shown in the attached figure 1.

Sheet resistance, by definition, represents the resistance per square area of dielectric surface to surface leakage current between two opposing sides of a square. The magnitude of the surface resistance depends on the structure and composition of the dielectric, as well as on the voltage, temperature, surface condition of the material, processing conditions and ambient humidity, which have a significant effect on the surface resistance of the dielectric. The measurement is generally carried out by a direct current amplification method, also known as a high impedance meter method. Specifically, the insulation resistance is measured by amplifying the weak current passing through the sample, and the basic principle is shown in fig. 2. When R0 Rx, R0 and Rx are connected in series, the formula U/Rx is U0/R0, and the surface resistance formula Rx is (U/U0) · R0, where: rx-measured gem resistance, (omega), U-test high voltage source voltage, (V), U0-voltage across standard resistor R0, (V), R0-standard resistor, (omega).

The two patent detection methods have obvious defects from the definition of the thermal conductivity and the surface resistance:

1. when the thermal conductivity is detected, only the heat E conducted after the probe on the thermal conductivity sensor is contacted with the gem is detected, namely the magnitude of the generated thermal potential after the temperature of the thermocouple on the probe on the thermal conductivity sensor is lost is measured.

The temperature gradient factor per unit temperature gradient is ignored, namely theta 2 and theta 1 are uncertain, so that the temperature gradient is different during detection. Thus, winter and summer or day and night (different room temperatures) result in different results from the same detector detecting the same gemstone.

Meanwhile, the unit time factor t is ignored, and the result is that the time for measuring one diamond (high thermal conductivity) reaches the value set by the circuit within 200 milliseconds, and the time for measuring one colorless large sapphire (low thermal conductivity) also reaches the value set by the circuit within 1500 milliseconds, so that the unit time is different during detection, and the thermal conductivity of the diamond and the sapphire is approximately 20 times different, as shown in fig. 3, but the detection result leads the two jewels to be mixed into the same result.

2. The potential gradient factor is ignored when the conductivity is detected, only the feedback voltage U0 after the high voltage passes through the jewel is detected, and the voltage U before the jewel is not detected. Due to the difference of components of the booster circuit, the fluctuation of the boosted high-voltage value is +/-10%, so that the potential gradient U-U0 is different during detection, and the consistency of the detection result is poor.

Meanwhile, the influence of the ambient temperature and the relative humidity on the result during detection is ignored. During detection, the surface resistance of the detected gem changes due to the change of the environmental temperature and the relative humidity, and further the detection result is influenced.

In summary, the above disadvantages make the gemstone detector in the original market only usable in a very small range of room temperature and relative humidity environment, only able to detect gemstones with large differences in thermal conductivity, unable to identify laboratory culture diamonds and gemstones with adjacent thermal conductivity, low detection resolution and poor consistency.

Therefore, it is an urgent need to solve the problem of providing a gemstone identification apparatus with high detection accuracy and wide application range.

Disclosure of Invention

In view of the above, the invention provides a gem identification device and method based on thermal conductivity and surface resistivity, which are used for identifying and distinguishing gems such as diamonds, laboratory-grown diamonds, morusite, red sapphire, emerald, crystal, emerald, spinel, tourmaline, topaz, tanzanite, garnet, cordierite, olivine, quartz, topaz and the like, and have high identification accuracy and wide application range.

In order to achieve the purpose, the invention adopts the following technical scheme:

a gemstone authentication device based on thermal conductivity and surface resistivity, comprising: the device comprises a thermal conductivity and conductivity sensor, a sensor temperature measurement and heating control module, a signal operational amplifier module, an AD acquisition module, a temperature and humidity sensor detection module, a high voltage generation module, a conductivity detection module, a single chip microcomputer module and a memory module;

the sensor temperature measurement heating control module is respectively connected with the thermal conductivity and conductivity sensor and the single chip microcomputer module and is used for measuring and heating the temperature of the thermal conductivity and conductivity sensor;

the signal operational amplifier module is respectively connected with the thermal conductivity and conductivity sensor and the AD acquisition module and is used for amplifying the level signal acquired from the thermal conductivity and conductivity sensor;

the AD acquisition module is connected with the singlechip module and is used for converting the amplified signal from analog quantity to digital quantity;

the temperature and humidity sensor detection module is connected with the single chip microcomputer module and used for collecting the ambient temperature and the relative humidity;

the high-voltage generation module is connected with the singlechip module and is used for generating a high-voltage direct-current power supply;

the conductivity detection module is respectively connected with the thermal conductivity sensor and the singlechip module and is used for collecting the feedback voltage of the measured gem after high voltage passes through the measured gem;

the single chip microcomputer module is used for analyzing, processing and controlling data and calculating heat conductivity and resistivity;

the memory module is connected with the singlechip module and is used for storing name data, color data, thermal conductivity value range data, resistivity value range data, thermal conductivity derivation formula data, surface resistance value derivation formula data of various gemstones and correction data of surface resistance change of the measured gemstones caused by relative humidity change.

Further, the thermal conductivity and conductivity sensor comprises a thermistor, a heating resistor and two pairs of thermocouples which are mutually attached and connected;

the two pairs of thermocouples respectively comprise copper alloy and constantan wires which are mutually connected, the copper alloy thermodes are shared and also used as electric conduction detection probes, the heating resistors generate heat sources to serve as probe hot ends, the cold ends of the probes are contacted with the jewel to be detected, the cold ends of the two pairs of thermocouples are respectively connected with the positive and negative input ends of an amplifier in the signal operational amplifier module, and the cold ends of the thermocouples are connected with the electric conduction detection module; the thermistor and the heating resistor are both connected with the sensor temperature measurement heating control module.

Further, the high voltage generation module comprises a DC-DC conversion circuit, a transformer and a voltage doubling rectifying circuit, wherein the DC-DC conversion circuit generates pulse voltage for signals of the single chip microcomputer module, and after the pulse voltage is boosted by the transformer, at least 600V high-voltage direct current power supply is generated through the voltage doubling rectifying circuit.

The alarm module is connected with the single chip microcomputer module and used for providing metal detection end potential and reference end potential; the buzzer warning module is connected with the single chip microcomputer module and used for emitting different warning sounds according to different detection results.

And the low-voltage detection module is connected with the single chip microcomputer module and used for detecting whether the voltage of the battery is lower than a set threshold value.

And the display module is connected with the singlechip module and used for displaying the detection process, the detection result and the warning information.

And the communication module is respectively connected with the single chip microcomputer module and the upper computer and is used for carrying out data transmission with the upper computer.

The system further comprises a button module, wherein the button module is connected with the single chip microcomputer module and used for realizing the functions of selecting, confirming, inputting, editing, storing and consulting through a menu.

Further, the device also comprises a voltage stabilizing module which is used for providing stable voltage for the whole device.

And the power supply control module is connected with the singlechip module and used for managing a USB external power supply and a battery power supply.

A method of gemstone identification based on thermal conductivity and surface resistivity, comprising:

step 1: the single chip microcomputer module collects temperature signals of a thermistor in the thermal conductivity and conductivity sensor through the sensor temperature measurement heating control module, applies voltage to the heating resistor in the thermal conductivity and conductivity sensor, and obtains the ambient temperature theta 1 and the relative humidity RH through collecting information on the temperature and humidity sensor detection module;

step 2: when the temperature signal of the thermistor acquired by the singlechip module reaches the probe temperature threshold range, entering a state to be detected, and acquiring the probe temperature theta 2;

and step 3: when the gemstone to be measured is contacted with the probe in the thermal conductivity sensor, the thermocouple in the thermal conductivity sensor outputs a level signal, the level signal is transmitted to the single chip microcomputer module through the signal operational amplifier module and the AD acquisition module, and when the single chip microcomputer module detects that the signal is larger than the electric potential energy threshold value, the single chip microcomputer module starts to time and simultaneously acquires the electric potential energy E generated after the thermocouple is cooled down within unit time t under unit temperature, so that the thermal conductivity of the gemstone to be measured is obtained;

and 4, step 4: comparing the measured thermal conductivity with the thermal conductivity threshold values of different gems stored in the memory module, and entering step 6 if the measured thermal conductivity belongs to the low thermal conductivity gems, and entering step 5 if the measured thermal conductivity belongs to the high thermal conductivity gems;

and 5: the single chip module activates the high voltage generation module, measures a high voltage source voltage U, measures a feedback voltage U0 of the high voltage source voltage after passing through the current conducting plate, the human body, the measured gem, the thermal conductivity and conductivity sensor and the conductivity detection module, calculates the surface resistivity of the measured gem, and obtains an identification result by comparing the surface resistivity with the numeric area data of the surface resistivity of the high thermal conductivity gem stored in the memory module;

meanwhile, according to the environmental temperature theta 1 and the relative humidity RH data acquired by the temperature and humidity sensor in real time, the surface resistance change of the measured gem caused by different temperatures and humidities is compensated and corrected;

step 6: and displaying a selected measured gem color interface, and respectively and correspondingly comparing the thermal conductivity and the selected color of the measured gem with the thermal conductivity threshold values and the color classification of the gemstones with different low thermal conductivities stored in the memory module to obtain an identification result.

According to the technical scheme, compared with the prior art, the invention discloses and provides the gem identification device and method based on the heat conductivity and the surface resistivity, so that the reliability and the accuracy of gem identification are improved, the detection capability of diamond cultivation and colored gems in a laboratory is improved, and the device and the method have wider latitude on the temperature and the relative humidity of the use environment.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic diagram of a thermal conductivity experiment.

FIG. 2 is a schematic diagram of resistivity experiment.

Figure 3 the accompanying figures show the relative thermal conductivity of various gemstones.

Figure 4 the accompanying drawing is a schematic block diagram of a gemstone identification device based on thermal conductivity and surface resistivity.

Fig. 5 is a schematic structural diagram of the thermal conductivity sensor.

The attached drawing of FIG. 6 is a specific circuit diagram of a sensor temperature measurement heating control module, a signal operational amplifier module, an AD acquisition module, a conductivity detection module and an alarm module.

Fig. 7 is a specific circuit diagram of the temperature and humidity sensor detection module.

Fig. 8 is a specific circuit diagram of the high voltage generating module.

Fig. 9 is a specific circuit diagram of the single chip microcomputer module.

FIG. 10 is a detailed circuit diagram of the memory module.

FIG. 11 is a detailed circuit diagram of the display module.

Fig. 12 is a specific circuit diagram of the buzzer warning module.

Fig. 13 is a detailed circuit diagram of the communication module.

Fig. 14 is a specific circuit diagram of the low voltage detection module and the voltage stabilization module.

Fig. 15 is a detailed circuit diagram of the button module and the power control module.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention discloses a gem identification device based on heat conductivity and surface resistivity, and the detection mechanism is simply explained. Each of the gems has its own unique physical properties, and due to their different materials, they have substantial differences in their respective thermal conductivities and surface resistances, which provide a basis for identifying diamonds, laboratory-grown diamonds, morusite, ruby, emerald, crystal, emerald, spinel, tourmaline, emerald, hypnage, topaz, tanzanite, garnet, cordierite, olivine, quartz, topaz, and other gems. From fig. 3, it can be understood that diamonds, laboratory grown diamonds, and morganite have thermal conductivities tens to hundreds of times higher than other gemstones.

In the technical scheme, diamonds, laboratory cultured diamonds and morusite are classified into high-thermal-conductivity gems, and other colored gems are classified into another low-thermal-conductivity gems.

It is also seen from Table 1 that the surface resistance of diamonds, laboratory grown diamonds, and Mosang stone, which are high thermal conductivity stones, are also different. Diamond is composed of carbon atoms. Natural diamonds are roughly divided into four main groups: type Ia, Type Ib, Type IIa, Type IIb, wherein Type Ia accounts for 98% of the total amount of the global mining, Type IIa accounts for less than 2%, and natural Type Ib, Type IIb are all very few. A common Type Ia is non-conductive, and only a small number of blue, blue-gray Type IIb diamonds are made conductive by doping with trace amounts of boron and phosphorus impurities. Laboratory diamond culture is carried out in a laboratory under the condition of simulating the natural formation of diamond, and is classified into CVD and HPHT according to different culture process technologies. Laboratory grown diamonds and diamonds are also C in chemical formula, but some additives and catalysts may be added in the growth environment and process, resulting in differences in thermal conductivity and surface resistance between diamonds and laboratory grown diamonds. Mosanglite is not C but Sic in chemical formula, and Si is a semiconductor, which is responsible for the difference in thermal conductivity and surface resistance between diamond and Mosanglite. The present invention is directed to the use of the principles described above for the detection of an identification gemstone.

TABLE 1 Diamond, laboratory grown diamonds, Moraxel thermal conductivity, surface resistivity contrast data

Name (R)	Diamond	Laboratory cultured diamond	Hehe or carbo silica (Mosang stone)
				Relative thermal conductivity	16000 or more	13000 or more	Over 12000
Surface resistance omega	10¹⁵～10¹⁸	10³～10¹⁴	10³～10⁶
				Chemical formula (II)	C	C	Sic

As shown in fig. 1, the device comprises a thermal conductivity and conductivity sensor 1, a sensor temperature measurement and heating control module 2, a signal operational amplifier module 3, an AD acquisition module 4, a temperature and humidity sensor detection module 5, a high voltage generation module 6, a conductivity detection module 7, a single chip microcomputer module 8, a memory module 9, a metal alarm module 10 for touching a sensor probe, a low voltage detection module 11, a display module 12, a buzzer warning module 13, a communication module 14, a voltage stabilization module 1, a power supply control module 16 and a button module 17.

The thermal conductivity sensor module 1 includes a heating resistor 101, an NTC thermistor 102, and two pairs of thermocouples 103. The heating resistor 101 is a metal film resistor, and is heated at a temperature of 45 ℃ or higher by applying a voltage. The two pairs of thermocouples 103 are both made of two thermode materials of two enameled constantan copper wires 1032 with the diameter of 0.13mm and a copper alloy with the diameter of 0.7mm, and the copper alloy with the diameter of phi 0.7mm also serves as a conductance detection probe 1031; a heating resistor 101 is attached to the probe 1031; the hot ends of the two pairs of thermocouples 103 are respectively welded on two sides of the probe 1031, and the cold ends of the two pairs of thermocouples are respectively connected with the positive and negative input ends of an amplifier in the signal operational amplifier module through a relay RL 1; the copper alloy probe 1031 is grounded. The thermal conductivity and electric conductivity sensor has two functions, one is acquisition of thermal conductivity signals; and secondly, acquiring a conductance signal of the measured gem through an electric loop formed by the conductive plate, the human body 18, the gem 19 and the copper alloy probe 1031.

The heating resistor generates heat after the current passes through the heating resistor to provide heat energy, the NTC thermistor feeds back a temperature signal, and the hot end of the thermocouple is contacted with the measured gem through the probe.

One end of the sensor temperature measurement and heating control module 2 is connected with the heating resistor and the NTC thermistor of the thermal conductivity sensor 1, and the other end is connected with the singlechip module. And transmitting a temperature signal fed back by the NTC thermistor and applying a voltage to the heating resistor.

And one end of the signal operational amplifier module 3 is connected with the other end of the thermal conductivity and conductivity sensor module 1 and is connected with the AD acquisition module 4. The differential amplifier LT1077, which includes but is not limited to a high-precision low-temperature drift single operational amplifier, amplifies the analog weak level signal obtained from the thermocouple of the thermal conductivity sensor module 1.

AD collection module 4, this module one end is connected fortune and is put module 3 other one end and connect singlechip module 8. The amplified signal output by the operational amplifier is converted from analog quantity to digital quantity. The AD acquisition module can be a single chip microcomputer with 12-bit AD or an external independent higher-bit AD chip.

And the temperature and humidity sensor detection module 5 is connected with the singlechip module 8. An SHT30 temperature and humidity chip circuit is adopted to acquire the current ambient temperature and relative humidity of a user in real time.

High pressure produces module 6, and this module one end is connected singlechip module 8, and the current conducting plate is connected to the other end. The DC-DC conversion circuit comprises a chip LT1316 of a micropower boost type DC/DC converter, and after a signal is sent to the singlechip module 8, pulse voltage is generated and boosted by a transmitter, and then the pulse voltage is matched with an external booster circuit through the voltage doubling rectification circuit to generate at least 600V high-voltage direct-current power supply.

The conductivity detection module 7, this module one end is connected thermal conductivity and conductivity sensor 1 thermocouple cold junction, and singlechip module 8 is connected to one end, detects high-voltage module 6 and produces high-voltage and high voltage and through being surveyed the voltage of feedback behind the precious stone, produces the high voltage and passes through R36, relay RL2, current conducting plate, human body, the precious stone of being surveyed, copper alloy probe 103, constantan wire 104, 105 arrival conductivity detection module.

The single chip microcomputer module 8 adopts a 32-bit single chip microcomputer, and comprises but is not limited to an STM32F103C8T6 chip.

The single chip module 8 is connected with the temperature measurement and heating control module 2 of the channel collection sensor, obtains NTC thermistor temperature signals in the thermal conductivity sensor module 1 by the temperature measurement and heating control module 2 of the channel collection sensor, thereby obtaining the sensor probe temperature theta 2 in the thermal conductivity derivation formula, and controls the temperature measurement and heating control module 2 of the sensor to apply voltage to the heating resistor in the thermal conductivity sensor module 1, so that the heating resistor is kept at the temperature of more than 45 ℃, and the temperature measurement and heating functions of the thermal conductivity sensor are realized.

The single chip microcomputer module 8 is connected with the temperature and humidity sensor detection module 5, the functions of ambient temperature and relative humidity on the temperature and humidity sensor detection module 5 are obtained, the temperature theta 1 of the measured jewel located on the relative section in the heat conductivity derivation formula is obtained through the ambient temperature, and meanwhile, information is corrected according to the surface resistance change of different jewel with different temperatures and humidity.

The singlechip module 8 is connected with the AD acquisition module 4 and used for acquiring the digital quantity of the operational amplifier output amplification signal and unit time information, so that the energy E transmitted in the time t in the heat conductivity derivation formula is acquired.

The single chip microcomputer module 8 is connected with the high voltage generation module 6, controls the high voltage generation module 6 to be matched with an external booster circuit to generate a high voltage source, and obtains the high voltage source voltage U in the surface resistance derivation formula.

One end of the singlechip module 8 is connected with the conductivity detection module 7, and the feedback voltage of the high voltage passing through the current conducting plate, the human body, the measured gem and the probe in the thermal conductivity and conductivity sensor 1 is collected to obtain the voltage U0 at the two ends of the surface resistance RX 21.

The single chip microcomputer module 8 calculates the thermal conductivity of the measured gem by using the obtained information of theta 1, theta 2 and E, t and according to a thermal conductivity derivation formula lambda, namely EI/At (theta 2-theta 1), wherein the lengths L of the probes on the thermal conductivity and conductivity sensor are the same, and the sectional area A of the thermal conductivity is the same. And calculating the surface resistance of the measured gemstone according to a surface resistance derivation formula Rx (U/U0) R0 by using the information of U and U0, wherein R0 is a fixed value. And correcting the surface resistance value of the gem by using the obtained environmental temperature and relative humidity, comparing the detection result with data stored in the memory module 9 in advance, and giving a judgment result.

The single chip microcomputer module 8 is connected with the alarm module 10, when the probe is in contact with Metal, a short circuit pull-down detection end potential is formed by a human body and the current conducting plate and is compared with a reference end potential, a Metal instruction is triggered and output, a Metal is displayed, and a user is prompted to detect again.

The memory module 9 is connected with the single chip microcomputer module 8, stores name data, color data, thermal conductivity value range data, electrical conductivity value range data, thermal conductivity derivation formula data, surface resistance value derivation formula data and correction data of surface resistance change of the measured precious stone caused by relative humidity change, and communicates information with the single chip microcomputer module 8.

And the alarm module 10 is used for detecting whether the probe of the electric conduction and thermal conduction sensor touches the metal or not and providing the metal detection end potential and the reference end potential for detection of the single chip microcomputer.

And the low-voltage detection module 11 is connected with the singlechip module 8, and gives an alarm to prompt a user to replace the battery when the voltage is lower than a threshold value.

And the display module 12 is connected with the singlechip module 8 and is used for displaying the detection process, the detection result and the warning.

The buzzer warning module 13 is connected with the singlechip module 8 and gives out different sounds to prompt a user according to different detection results.

And one end of the communication module 14 is connected with the singlechip module 8, and the other end of the communication module is connected with an upper computer. The relevant data of the diamonds, the Morusite and the colored gems can be transmitted, input and stored, edited, deleted and consulted by the upper computer.

And the voltage stabilizing module 15 provides the whole device stabilizing voltage.

And the power control module 16 has one end connected with the singlechip module 8 and the other end connected with the USB external connection and the battery power supply, and is used for turning off the power supply when the power is started and is not used for a long time so as to manage the USB external connection and the battery dual power supply.

And the button module 17 is connected with the singlechip module 8, so that a user can perform functions of selecting, confirming, inputting, editing, storing and consulting menu display information.

step 1: initializing self-checking after a long-time press switch is started;

step 2: the single chip microcomputer module collects temperature signals of the thermistor on the thermal conductivity and conductivity sensor through the sensor temperature measurement heating control module and applies voltage to the heating resistor on the thermal conductivity and conductivity sensor for heating. Acquiring information on a temperature and humidity sensor detection module to obtain an ambient temperature theta 1 and a relative humidity HR;

and step 3: when the temperature signal of the thermistor acquired by the singlechip module reaches the range of the temperature threshold of the probe, entering a state to be detected, and simultaneously obtaining the temperature theta 2 of the probe;

and 4, step 4: when the gem to be measured is contacted with a probe of the thermal conductivity and conductivity sensor, the thermocouple outputs a level signal, the level signal is transmitted to the singlechip module through the signal operational amplifier module and the AD acquisition module, and when the singlechip module detects that the signal is greater than a potential energy threshold value, the singlechip module starts to time and simultaneously acquires potential energy E generated after the thermocouple loses temperature within unit time t at unit temperature, so that the thermal conductivity of the gem to be measured is obtained;

and 5: comparing the measured thermal conductivity with thermal conductivity thresholds of different types of gems preset in a memory module, and entering step 7 if the measured thermal conductivity belongs to a low-thermal-conductivity gem, and entering step 6 if the measured thermal conductivity belongs to a high-thermal-conductivity gem; gemstones are classified into two main categories by different categories of thermal conductivity thresholds;

step 6: activating a high-voltage generation module, measuring a high-voltage source voltage U, measuring a feedback voltage U0 of the high-voltage source voltage after the high-voltage source voltage passes through a current-conducting plate, a human body, the measured gem, a thermal conductivity and conductivity sensor and a conductivity detection module, calculating the surface resistivity of the measured gem, and comparing the surface resistivity with the numeric area data of the surface resistivity of the high-thermal conductivity gem preset in a memory module to obtain an identification result;

and 7: since the resistivity of the low-thermal conductivity gemstones is not greatly different, the gemstones are not subjected to resistivity detection and are identified by colors. Specifically, the method comprises the following steps: and displaying and selecting a color interface of the measured gem, and comparing the thermal conductivity and the selected color of the measured gem with thermal conductivity thresholds and colors of the gemstones with different low thermal conductivities preset in the memory module in a classified manner to obtain an identification result.

Preferably, in step 3, if the temperature of the thermal conductivity and conductivity sensor exceeds 45 seconds and is lower than the threshold range, the EE1 is displayed to indicate that the thermal conductivity and conductivity sensor is damaged, and if the temperature and humidity sensor is damaged, the EE2 is displayed to indicate that the temperature and humidity sensor is damaged, and the automatic shutdown is performed after 30 seconds.

Preferably, in step 4, if the output signal of the thermocouple on the 6-minute thermal conductivity sensor is not greater than the set thermal conductivity threshold 1, the power supply is automatically switched to the power saving mode to be turned off.

Preferably, in step 4, if the probe touches a Metal, such as a decoration on the hand, during the detection, the detection is stopped, the Metal is displayed, and the module is warned by a buzzer to emit a high frequency drop.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A gemstone authentication device based on thermal conductivity and surface resistivity, comprising: the device comprises a thermal conductivity and conductivity sensor, a sensor temperature measurement and heating control module, a signal operational amplifier module, an AD acquisition module, a temperature and humidity sensor detection module, a high voltage generation module, a conductivity detection module, a single chip microcomputer module and a memory module;

2. The gemstone authentication device of claim 1, wherein the thermoconductive and electrically conductive sensor comprises a thermistor, a heating resistor and two pairs of thermocouples in abutting connection with each other;

3. The gemstone identification device according to claim 1, wherein the high voltage generation module comprises a DC-DC conversion circuit, a transformer and a voltage doubling rectifier circuit, the DC-DC conversion circuit generates pulse voltage for the signal of the single chip microcomputer module, and after the pulse voltage is boosted by the transformer, the voltage doubling rectifier circuit generates at least 600V high voltage DC power supply.

4. The gemstone identification device based on thermal conductivity and surface resistivity as claimed in claim 2 or 3, further comprising an alarm module and a buzzer warning module, wherein the alarm module is connected with the single chip microcomputer module and is used for providing a metal detection end potential and a reference end potential; the buzzer warning module is connected with the single chip microcomputer module and used for emitting different warning sounds according to different detection results.

5. The gemstone authentication device of claim 4, further comprising a low voltage detection module coupled to the single-chip microcomputer module for detecting if the battery voltage is below a set threshold.

6. The gemstone identification device according to claim 5, further comprising a display module, wherein the display module is connected to the single chip microcomputer module for displaying the detection process, the detection result and the warning information.

7. The gemstone identification device according to claim 6, further comprising a communication module, wherein the communication module is respectively connected to the single chip microcomputer module and the upper computer, and is used for data transmission with the upper computer.

8. The gemstone authentication device according to claim 7, further comprising a button module and a power control module, wherein the button module is connected to the single chip module for implementing functions of selecting, confirming, inputting, editing, storing and referring through menus; the power supply control module is connected with the single chip microcomputer module and used for managing a USB external power supply and a battery power supply.

9. The gemstone authentication device of claim 8, further comprising a voltage stabilization module for providing a stabilized voltage to the entire device.

10. A method of gemstone identification based on thermal conductivity and surface resistivity, comprising: