A near-field thermal radiation independent detector, preparation method and measurement method

Abstract

The present invention provides a near-field thermal radiation independent detector, comprising: a glass plate (3), a hollow separation medium layer (4) formed on the lower surface of which; the separation medium layer (4) is in direct contact with the plate to be measured, so that a fixed heat exchange spacing is formed between the glass plate (3) and the plate to be measured; a metal wire electrode (1), formed on the upper surface of the glass plate (3), comprising a planar double helix structure metal wire, one end of the double helix structure metal wire is connected to the center of the spiral, and the other end is respectively connected to four lead pieces (2), two of which are used to heat the double helix structure metal wire, and the other two lead pieces are used to measure the resistance of the double helix structure metal wire in real time, and the average temperature rise is obtained according to the resistance value as a parameter for obtaining the near-field radiation heat transfer coefficient. The present invention can improve the integration of the near-field thermal radiation measurement system and the repeatability of sample testing, and is helpful for the acquisition of near-field thermal radiation basic data and the technical application of the near-field thermal photovoltaic system.

Description

Technical Field

[0001] The present invention relates to the technical field of radiation heat exchange measurement, and in particular to a near-field thermal radiation independent detector, a preparation method and a measurement method. Background Art

[0002] Thermophotovoltaic technology is a technology that directly converts the energy of a high-temperature thermal radiator into electrical energy through a semiconductor PN junction. It is an advanced waste heat recovery technology. However, due to the limitations of the blackbody radiation spectrum range and the bandgap width of existing thermophotovoltaic cells, the power output power and energy conversion efficiency of traditional thermophotovoltaic systems are far lower than the theoretical values. A large number of theoretical studies have shown that near-field thermophotovoltaic systems (NFTPVs) can significantly improve the heat exchange flux between the radiator and the thermophotovoltaic cell by utilizing the near-field radiation resonance enhancement effect, thereby enhancing the power output of the system. However, how to construct the near field and realize the effective measurement of the near-field thermal radiation signal in experiments is currently an international research hotspot and difficulty in this field, and is also a core issue that restricts the application of technology.

[0003] There are currently no mature near-field thermal radiation measurement instruments at home and abroad, and near-field thermal radiation measurement work mainly remains in the experimental research stage. In the past decade, research groups such as the Massachusetts Institute of Technology, Toyota Central Research and Development Laboratory, Georgia Institute of Technology, University of Salt Lake City, and Zhejiang University have successively carried out experimental research on near-field thermal radiation of fixed-gap parallel dielectric plates. Although the details of the above experimental measurements are different, all experimental systems are bound by a fixed measurement mode: one end of the experimental system is heated by a constant power heat source, and the other end is at a lower temperature. When the system reaches a steady state, the temperature of the cold end and the hot end is measured; in order to reduce the additional heat conduction of the steady-state system, the fixed gap separation medium can usually only be constructed using methods such as low thermal conductivity particles and sparse arrays. The experimental design of this steady-state method has resulted in NFTPVs still not being put into practical use. The main reasons are as follows: (1) The temperature sensor and radiator / absorber must be installed on the heating copper plate / substrate copper plate in the system, and the contact thermal resistance for the temperature measurement of the heater / cooler is inevitable; (2) The thermal resistance and loss of all geometric structure interfaces between the sensors must be carefully estimated before measurement. The data processing process is cumbersome, and the proportion of heat conduction is still large compared to near-field thermal radiation, resulting in a decrease in the accuracy of near-field radiation measurement; (3) The introduction of temperature sensors, heating copper plates, and parallel calibration auxiliary devices makes the experimental system very complicated, resulting in the sparse separation medium being easily damaged during the experiment, resulting in a low measurement repetition rate, which is not conducive to the overall construction of NFTPVs and the subsequent integration and device development.

[0004] Researchers from Hamburg University of Technology in Germany used a commercial transient planar heat source probe as a heat source and temperature sensor, obtained the dynamic change curve of the probe temperature over time, and obtained the near-field radiation heat transfer coefficient under different heat exchange spacings by iteratively solving the inverse problem of the one-dimensional Fourier heat conduction model. The transient measurement experimental system proposed in this paper is simpler than the steady-state system, and can distinguish the influence of near-field radiation and interlayer contact thermal resistance on the measurement results on a time scale, which puts forward a new idea for solving the problem of near-field radiation detection accuracy. However, the one-dimensional heat conduction model does not consider the spatial distribution of the temperature of the parallel plate structure and its dynamic change over time during the transient heating process, nor does it consider the influence of composite heat transfer factors such as background radiation and sensor interface loss; furthermore, the heat exchange spacing in the form of nanoparticles leads to a larger thermal conduction ratio of the separation medium relative to the near field, and the measurement process fails to distinguish the thermal conduction energy of the separation medium that occurs simultaneously with the near-field radiation, which is not conducive to the realization of the NFTPVs system; in addition, the contact thermal resistance introduced each time during the commercial probe fixing process is different, which also increases the difficulty of numerical inversion.

[0005] In summary, the near-field radiation measurement work of fixed-gap parallel plate structures that has been carried out usually adopts a steady-state measurement mode, which results in low experimental repetition rate and limited measurement accuracy. The transient measurement research of near-field radiation of fixed-gap parallel plate structures is still in its initial stage. Although some experimental data of near-field radiation transient measurement have been obtained based on commercial planar heat source probes, there is still a lack of systematic and complete theoretical models and experimental systems. The development of near-field radiation measurement technology with high measurement accuracy, high repetition rate and integration has important scientific significance and application value. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] In view of the above problems, the present invention provides an independent near-field thermal radiation detector, a preparation method and a measurement method, which are used to at least partially solve the technical problems of low test repetition rate and complex test system in traditional near-field thermal radiation measurement between fixed gaps.

[0008] (II) Technical solution

[0009] On the one hand, the present invention provides an independent detector for near-field thermal radiation, comprising: a glass plate 3, a hollow separation medium layer 4 is formed on the lower surface of which; the separation medium layer 4 is in direct contact with the plate to be measured, so that a fixed heat exchange distance is formed between the glass plate 3 and the plate to be measured; a metal wire electrode 1, formed on the upper surface of the glass plate 3, comprising a planar double-helix structure metal wire, one end of the double-helix structure metal wire is connected to the center of the spiral, and the other end is respectively connected to four lead pieces 2, two of which are used to heat the double-helix structure metal wire, and the other two lead pieces are used to measure the resistance of the double-helix structure metal wire in real time, and an average temperature rise is obtained according to the resistance value, which is used as a parameter for obtaining the near-field radiation heat transfer coefficient.

[0010] Furthermore, the separation medium layer 4 includes a prism-shaped structure, a columnar structure, and a ring-shaped structure.

[0011] Furthermore, the separation medium layer 4 is a prism-shaped structure, which is located at the edge of the lower surface of the glass plate 3, and the bottom surface geometric structure is a square.

[0012] Furthermore, the material of the metal wire electrode 1 includes nickel and platinum.

[0013] Furthermore, the thickness of the metal wire electrode 1 is 100 nm to 500 nm, and the temperature coefficient of resistance thereof is in the range of 0.0035 to 0.0069.

[0014] Furthermore, the thickness of the glass plate 3 is in the range of 0.5 mm to 1 mm, and the height of the separation medium layer 4 is in the range of 150 nm to 2000 nm.

[0015] Furthermore, the material of the separation dielectric layer 4 includes silicon dioxide and SU-8 photoresist.

[0016] On the other hand, the present invention provides a method for preparing an independent detector for near-field thermal radiation, comprising: S1, depositing a silicon dioxide film of a specific thickness on the lower surface of a glass plate 3; S2, etching the silicon dioxide film to prepare a hollow separation medium layer 4; the separation medium layer 4 is in direct contact with the plate to be tested, so that a fixed heat exchange distance is formed between the glass plate 3 and the plate to be tested; S3, sputtering a metal wire electrode 1 on the upper surface of the glass plate 3, comprising a planar double-helix structure metal wire, one end of the double-helix structure metal wire is connected to the center of the spiral, and the other end is respectively connected to four lead pieces 2, two of which are used to heat the double-helix structure metal wire, and the other two lead pieces are used to measure the resistance of the double-helix structure metal wire in real time, and the average temperature rise is obtained according to the resistance value, which is used as a parameter for obtaining the near-field radiation heat transfer coefficient.

[0017] Furthermore, after S3, the method further includes: S4, applying glue to protect the surface of the double helix structure metal wire electrode 1 .

[0018] Another aspect of the present invention provides a method for measuring the near-field radiation heat transfer coefficient, comprising: S1, placing the aforementioned near-field thermal radiation independent detector above the plate to be measured, with the separating medium layer 4 in direct contact with the plate to be measured, so that a fixed heat exchange distance is formed between the glass plate 3 and the plate to be measured; S2, heating the double-helix structure metal wire through two of the lead pieces, and measuring the resistance of the double-helix structure metal wire in real time with the other two lead pieces, and obtaining the average temperature rise according to the resistance; S3, calculating the parameters of the near-field radiation heat transfer coefficient: the thermal radiation flux between the plates is expressed as follows:

[0019]

[0020] Among them, T1 is the temperature of the effective heat source at the center of the upper plate, T2 is the temperature at the corresponding position of the lower plate, ζ j (ω, K) is the energy transfer coefficient between the two parallel plates; Θ(ω, T) is the average energy of the Planck oscillator at frequency ω under thermal equilibrium; ω is the radiation frequency, K is the transverse wave vector parallel to the surface of the plate, s is the transverse electric wave, and p is the transverse magnetic wave; then the radiation heat transfer coefficient h R as follows:

[0021]

[0022] (III) Beneficial effects

[0023] The near-field thermal radiation independent detector, preparation method and measurement method provided by the embodiment of the present invention use a double helix structure metal wire electrode as a planar heat source and temperature difference sensor to directly detect the average temperature rise of the quartz glass plate; the double helix structure metal wire electrode and the prism-shaped structure separation medium are used in combination to form an independent detector, which can directly measure the near-field radiation heat transfer coefficient of the fixed gap parallel plate structure, and can largely solve the difficult problems of low test repetition rate and complex test system in the near-field thermal radiation experimental measurement between fixed gap parallel medium plates, and there is no need to arrange temperature sensors and planar heat sources additionally, and the measurement probe is movable. At the same time, the double helix structure metal wire can reduce the contact thermal resistance, and the optional design of the separation medium layer and the double helix structure metal wire can minimize the influence of heat conduction on the near-field thermal radiation measurement accuracy during the transient measurement process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The schematic diagram shows the structure of a near-field thermal radiation independent detector according to an embodiment of the present invention;

[0025] Figure 2 The schematic diagram shows the structure of a double-helix structure metal wire electrode in a near-field thermal radiation independent detector according to an embodiment of the present invention;

[0026] Figure 3The schematic diagram shows the structure of the prism-shaped structure separation medium in the near-field thermal radiation independent detector according to an embodiment of the present invention;

[0027] Figure 4 The flowchart schematically shows a method for preparing a near-field thermal radiation independent detector according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0029] The embodiment of the present disclosure provides a near-field thermal radiation independent detector, see Figure 1 , including: a glass plate 3, a hollow separation medium layer 4 is formed on the lower surface of which; the separation medium layer 4 is in direct contact with the plate to be measured, so that a fixed heat exchange distance is formed between the glass plate 3 and the plate to be measured; a metal wire electrode 1, formed on the upper surface of the glass plate 3, including a planar double-helix structure metal wire, one end of the double-helix structure metal wire is connected to the center of the spiral, and the other end is respectively connected to four lead pieces 2, two of which are used to heat the double-helix structure metal wire, and the other two lead pieces are used to measure the resistance of the double-helix structure metal wire in real time, and the average temperature rise is obtained according to the resistance value, which is used as a parameter for obtaining the near-field radiation heat transfer coefficient.

[0030] The near-field thermal radiation detector includes: a double-helix metal wire electrode, a quartz glass plate and a prism-shaped structure separation medium. The double-helix metal wire electrode is located on the upper surface of the upper dielectric plate. It is both a surface heat source for heating the upper dielectric plate and a resistance temperature sensor for recording the temperature change over time. The double-helix structure increases the contact area between the heat source and the quartz glass substrate and reduces the contact thermal resistance. It also has high temperature measurement accuracy and sensitivity. The prism-shaped structure separation medium is directly etched on the quartz glass substrate to form the support column of the independent detector and construct a fixed height heat exchange spacing.

[0031] Here, the double helix structure wire is two wires, both of which are spiral-shaped and arranged in an interlaced manner. One end of the two wires is connected at the center of the spiral, and the other ends of the two wires are connected to the lead parts respectively. The double helix structure wire electrode is used as a planar heat source and temperature difference sensor to directly detect the average temperature rise of the quartz glass plate. The double helix structure wire electrode is used in conjunction with a prism-shaped structure separation medium to form an independent detector, which can directly measure the near-field radiation heat transfer coefficient of a fixed gap parallel plate structure (the plate being measured is not shown here). Figure 2The schematic diagram of the structure of the double helix structure metal wire electrode is shown in FIG. The metal wire electrode 1 includes a double helix metal wire and four lead wires. The other ends of the four lead wires have four lead wire ends. A constant voltage DC power supply is selected to connect two of the lead wire ends to perform constant voltage heating on the double helix metal strip, and the remaining two lead wire ends are connected to a thermal resistance measurement module to measure the resistance change of the double helix structure metal wire electrode 1 in real time.

[0032] It should also be noted that the glass plate 3 uses a double-sided polished quartz substrate, which can ensure that the quartz glass substrate has a high surface flatness and a small degree of curvature within a limited size. Quartz glass has a low thermal conductivity, which can reduce the temperature rise rate at the edge of the quartz glass substrate within a limited time, further reduce the heat conduction of the prism-shaped structure separation medium, and improve the detection accuracy of near-field thermal radiation.

[0033] On the basis of the above-mentioned embodiment, the separation medium layer 4 includes a prism-shaped structure, a columnar structure, and a ring-shaped structure.

[0034] The separation medium layer 4 plays the role of constructing a fixed heat exchange spacing. The bottom area of ​​the separation medium layer 4 needs to be as small as possible to reduce the heat conduction energy of the upper medium plate entering the lower medium plate through the separation medium. Here, the separation medium layer 4 can adopt a prism structure, a columnar structure, an annular structure, etc., and its specific structure can be various, and the separation medium layer is not limited to the aforementioned three structures.

[0035] On the basis of the above embodiment, the separation medium layer 4 is a prism-shaped structure, which is located at the edge of the lower surface of the glass plate 3, and the bottom surface geometric structure is a square.

[0036] The separation medium layer 4 can be a prism-shaped structure separation, located at the edge of the medium plate. The prism-shaped separation medium is a square with a bottom surface geometry of 2 mm side length, see Figure 3 The use of this prism-shaped separation medium in conjunction with a double-helix structured metal wire can reduce the heat conduction of the separation medium within a limited measurement time and improve the accuracy of near-field thermal radiation detection.

[0037] Based on the above embodiment, the material of the metal wire electrode 1 includes nickel and platinum.

[0038] The double helix wire and four lead parts are made of nickel or platinum metal, and are attached to the upper dielectric plate through etching or vapor deposition to form a double helix structure with a thickness of hundreds of nanometers. It has a high temperature resistance coefficient and a high detection sensitivity for very small temperature changes. Because the resistance temperature coefficient of the double helix wire electrode is different from that of the macro material at the microscale, the resistance temperature coefficient of different batches of double helix wire electrodes needs to be experimentally calibrated before the measurement begins.

[0039] On the basis of the above-mentioned embodiment, the thickness of the metal wire electrode 1 is 100 nm to 500 nm, and the range of its temperature coefficient of resistance is (0 to 100 degrees Celsius) 0.0035 to 0.0069.

[0040] The metal wire electrode is attached to the quartz glass substrate 3 through a magnetron sputtering coating process to form a double helix structure with a thickness of hundreds of nanometers. It has a high resistance temperature coefficient and a high detection sensitivity for very small temperature changes. The thickness of the metal wire electrode 1 cannot be too thick, otherwise the metal wire electrode will be blown due to the small resistance value; the thickness of the metal wire electrode 1 cannot be too thin, otherwise the temperature rise of the metal wire will be small due to the large resistance value, reducing the experimental detection accuracy. The resistance temperature coefficient varies within this range due to different processing batches and experimental conditions, but has good linearity in the range of 0 to 100 degrees Celsius, so that the temperature rise of the metal wire electrode can be accurately measured.

[0041] On the basis of the above embodiment, the thickness of the glass plate 3 is in the range of 0.5 mm to 1 mm, and the height of the separation medium layer 4 is in the range of 150 nm to 2000 nm.

[0042] The thickness of the glass plate 3 has a certain compressive strength within this range and is much smaller than the area of ​​the glass plate, and can effectively reduce the boundary heat radiation loss. The height of the separating medium layer 4 cannot be too high because the near-field radiation effect is not significant enough under room temperature conditions; it cannot be too low to avoid contact between the upper and lower plates due to bending and parallelism problems of the glass plate.

[0043] Based on the above embodiment, the material of the separation dielectric layer 4 includes silicon dioxide, SU-8 photoresist and other materials with high compressive strength and low thermal conductivity.

[0044] The material of the separation medium layer 4 is a silicon dioxide material with low thermal conductivity and high compressive strength. The lower thermal conductivity can reduce the heat conduction of the prism-shaped separation medium, and the higher compressive strength can reduce the bottom area of ​​the prism-shaped separation medium, further weakening the heat conduction energy of the upper medium plate entering the lower medium plate through the separation medium.

[0045] Another embodiment of the present disclosure provides a method for preparing a near-field thermal radiation independent detector, see Figure 4, including: S1, depositing a silicon dioxide film of a specific thickness on the lower surface of the glass plate 3; S2, etching the silicon dioxide film to prepare a hollow separation medium layer 4; the separation medium layer 4 is in direct contact with the plate to be tested, so that a fixed heat exchange distance is formed between the glass plate 3 and the plate to be tested; S3, sputtering a metal wire electrode 1 on the upper surface of the glass plate 3, including a planar double-helix structure metal belt, one end of the double-helix structure metal belt is connected to the center of the spiral, and the other end is respectively connected to four lead pieces 2, two of which are used to heat the double-helix structure metal belt, and the other two lead pieces are used to measure the resistance of the double-helix structure metal belt in real time, and the average temperature rise is obtained according to the resistance value, which is used as a parameter for obtaining the near-field radiation heat transfer coefficient.

[0046] Here, step S1 specifically includes: preparing a silicon dioxide film of a specific thickness on the lower surface of double-sided polished quartz glass by chemical vapor deposition, and the thickness of the film determines the near-field radiation heat exchange spacing. Step S2: preparing a prism-shaped structure separation medium on the silicon dioxide film on the lower surface of double-sided polished quartz glass by wet etching process to form the support column of the independent detector; step S3: preparing a double-helix structure metal wire electrode on the upper surface of quartz glass by mask exposure combined with magnetron sputtering, as a planar heat source and temperature difference sensor.

[0047] On the basis of the above embodiment, after S3, the following further includes: S4, coating the surface of the double helix structure metal wire electrode 1 with glue for protection.

[0048] After the overall structure of the independent detector is prepared, it also includes protecting the surface of the double-helix metal wire with glue, scribing and cleaning, and using a step meter to characterize and confirm the height of the prism-shaped structure separation medium.

[0049] Another embodiment of the present disclosure provides a method for measuring a near-field radiation heat transfer coefficient, comprising: S1, placing the aforementioned near-field thermal radiation independent detector above the plate to be measured, with the separating medium layer 4 in direct contact with the plate to be measured, so that a fixed heat exchange distance is formed between the glass plate 3 and the plate to be measured; S2, heating the double-helix structure metal strip through two of the lead pieces, and measuring the resistance of the double-helix structure metal strip in real time through the other two lead pieces, and obtaining an average temperature rise according to the resistance; S3, calculating the parameters of the near-field radiation heat transfer coefficient: the thermal radiation flux between the plates is expressed as follows:

[0050]

[0051] Among them, T1 is the temperature of the effective heat source at the center of the upper plate, T2 is the temperature at the corresponding position of the lower plate, ζ j(ω, K) is the energy transfer coefficient between the two parallel plates; Θ(ω, T) is the average energy of the Planck oscillator at frequency ω under thermal equilibrium; ω is the radiation frequency, K is the transverse wave vector parallel to the surface of the plate, s is the transverse electric wave, and p is the transverse magnetic wave; then the radiation heat transfer coefficient h R as follows:

[0052]

[0053] In this implementation, it is necessary to establish and analyze the measurement model of the near-field thermal radiation independent detector. The specific implementation steps are as follows: Use COMSOL Multiphysics software to perform three-dimensional geometric modeling of the near-field radiation transient measurement system proposed in this project through the standard modeling process, create a coupled current heat source and solid heat transfer physical field model, and set material properties and physical field boundary conditions.

[0054] Preferably, the CMY thermal contact model is used to define the thermal contact resistance according to the surface morphology and contact pressure of the parallel plates. The system boundary emissivity is defined according to the emissivity of the material to obtain the background radiation energy. Under near-field conditions, in order to simultaneously analyze the effects of heat conduction, background radiation and near-field radiation on the temperature distribution law, the initially established model needs to be revised again. Preferably, we regard the vacuum heat exchange interval between the parallel plates as an equivalent medium and define the heat transfer coefficient h between the vacuum layer and the medium plate R The equivalent heat transfer coefficient of the vacuum layer at a specific experimental temperature can be calculated according to the following process.

[0055] According to the fluctuation dissipation theory, the thermal radiation flux between two half infinite parallel plates with a distance d can be expressed as follows:

[0056]

[0057] In the above formula, T1 is the temperature of the effective heat source at the center of the upper plate, T2 is the temperature at the corresponding position of the lower plate, and ζ j (ω, K) is the energy transfer coefficient between two parallel plates, its maximum value is 1, which can be written as follows:

[0058]

[0059] Where K is the transverse wave vector parallel to the surface of the dielectric plate, γ is the longitudinal wave vector in the z direction perpendicular to the surface, and j = s, p, r s and r p represent the Fresnel reflection coefficient of the dielectric slab for s-polarized and p-polarized incident light, respectively.

[0060] Θ(ω, T) is the average energy of the Planck oscillator at frequency ω in thermal equilibrium and can be expressed as follows:

[0061]

[0062] Therefore, the radiation heat transfer coefficient h R as follows:

[0063]

[0064] After the above steps, the numerical simulation results of the electrode temperature rise over time under different electrode voltages are obtained. By correcting the heat transfer coefficient between the plate and the vacuum equivalent medium, the contact thermal resistance between the upper and lower plates, and the contact thermal resistance of the thermal conductive silicone grease, the numerical simulation results of the electrode temperature rise-time under different electrode voltages are fitted with the experimental results to obtain the near-field radiation heat transfer coefficient.

[0065] Preferably, the metal electrode is connected to a lock-in amplifier, an AC voltage of about 0.001 mV is applied to the lock-in amplifier, and the voltage of the metal electrode and the resistance box is adjusted by adjusting a precision resistance box to roughly obtain the initial resistance value of the metal electrode.

[0066] Preferably, in order to reduce the influence of air heat conduction on the measurement results, the independent detector and the sample to be measured should be placed in a vacuum cover before the measurement starts, and the vacuum degree in the vacuum chamber should be kept less than 10 -4 Pa, record the ambient temperature.

[0067] The metal electrode is connected to the DC power supply again. Preferably, in order to remove the resistance change of the DC wire and the resistance effect caused by the vacuum degree, a DC voltage of 30mV is applied to the electrode, and the voltage of the metal electrode and the resistance box is leveled again under the DC condition by fine adjustment, and record 1: the initial resistance value R0 of the electrode.

[0068] Preferably, the double helix structure metal wire electrode and the DC stabilized power supply are connected in series to the resistance data acquisition system; the DC stabilized power supply is adjusted to output a stable voltage, the electrode resistance change is collected in real time, and the temperature rise of the double helix structure metal wire electrode over time is obtained through the resistance temperature coefficient. The numerical simulation results of the electrode temperature rise-time relationship are further fitted with the experimental results to obtain the near-field radiation heat transfer coefficient between the parallel plates.

[0069] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A near-field thermal radiation independent detector, characterized in that: include: A glass flat plate (3) having a hollow separation medium layer (4) formed on its lower surface; the separation medium layer (4) is in direct contact with the plate to be tested, so that a fixed heat exchange distance is formed between the glass flat plate (3) and the plate to be tested; A metal wire electrode (1) is formed on the upper surface of the glass plate (3), comprising a planar double helix structure metal wire, one end of the double helix structure metal wire is connected to the center of the helix, and the other end is respectively connected to four lead pieces (2), two of which are used to heat the double helix structure metal wire, and the other two lead pieces are used to measure the resistance of the double helix structure metal wire in real time, and an average temperature rise is obtained according to the resistance, which is used as a parameter for obtaining the near-field radiation heat transfer coefficient; The measurement steps are as follows: S1, placing a near-field thermal radiation independent detector above the plate to be tested, and placing a separating medium layer (4) in direct contact with the plate to be tested, so that a fixed heat exchange distance is formed between the glass plate (3) and the plate to be tested; S2, heating the double helix structure metal wire through two of the lead pieces, measuring the resistance of the double helix structure metal wire in real time with the other two lead pieces, and obtaining an average temperature rise according to the resistance; S3, calculate the parameters of the near-field radiation heat transfer coefficient: the heat radiation flux between the flat plates is expressed as follows: Among them, T1 is the temperature of the effective heat source at the center of the upper plate, T2 is the temperature at the corresponding position of the lower plate, ζ j (ω,K) is the energy transfer coefficient between two parallel plates; is the average energy of the Planck oscillator at frequency ω under thermal equilibrium; ω is the radiation frequency, K is the transverse wave vector parallel to the surface of the plate, s is the transverse electric wave, and p is the transverse magnetic wave; Then the radiation heat transfer coefficient h R as follows: 。 2. The near-field thermal radiation independent detector according to claim 1, characterized in that: The separation medium layer (4) comprises a prism-shaped structure, a columnar structure, and a ring-shaped structure.

3. The near-field thermal radiation independent detector according to claim 2, characterized in that: The separation medium layer (4) is a prism-shaped structure, which is located at the edge of the lower surface of the glass plate (3), and the bottom surface geometric structure is a square.

4. The near-field thermal radiation independent detector according to claim 1, characterized in that: The material of the metal wire electrode (1) includes nickel and platinum.

5. The near-field thermal radiation independent detector according to claim 4, characterized in that: The thickness of the metal wire electrode (1) is 100-500 nm, and the temperature coefficient of resistance thereof is in the range of 0.0035-0.0069.

6. The near-field thermal radiation independent detector according to claim 1, characterized in that: The thickness of the glass plate (3) ranges from 0.5 mm to 1 mm, and the height of the separation medium layer (4) ranges from 150 nm to 2000 nm.

7. The near-field thermal radiation independent detector according to claim 6, characterized in that: The materials of the separation dielectric layer (4) include silicon dioxide and SU-8 photoresist.

8. A method for preparing a near-field thermal radiation independent detector, applied to the near-field thermal radiation independent detector according to any one of claims 1 to 7, comprising: S1, depositing a silicon dioxide film of a specific thickness on the lower surface of the glass plate (3); S2, etching the silicon dioxide film to prepare a hollow separation medium layer (4); the separation medium layer (4) is in direct contact with the plate to be tested, so that a fixed heat exchange distance is formed between the glass plate (3) and the plate to be tested; S3, sputtering a metal wire electrode (1) on the upper surface of the glass plate (3), comprising a planar double helix structure metal wire, wherein one end of the double helix structure metal wire is connected to the center of the helix, and the other end is respectively connected to four lead pieces (2), wherein two lead pieces are used to heat the double helix structure metal wire, and the other two lead pieces are used to measure the resistance of the double helix structure metal wire in real time, and an average temperature rise is obtained according to the resistance, which is used as a parameter for obtaining the near-field radiation heat transfer coefficient.

9. The method for preparing a near-field thermal radiation independent detector according to claim 8, further comprising after S3: S4, applying glue to protect the surface of the double helix structure metal wire electrode (1).

Images