A device and method for detecting defects and analyzing components of a reflective non-metallic substance

Abstract

The present invention discloses a reflection-type non-metallic material defect detection and component analysis device and method. The device includes a linearly frequency modulated source module, a solid-state switch matrix, a low-noise amplifier module group, a terahertz signal transceiver device, an intermediate-frequency signal acquisition module, and a host computer that are connected in sequence. The terahertz signal transceiver device includes a first split-type terahertz signal transceiver integrated link group, a second split-type terahertz signal transceiver integrated link group, a first pair of terahertz antennas, a first transparent non-polarizing beam splitter, a first multi-focus parabolic mirror, a second pair of terahertz antennas, a second transparent non-polarizing beam splitter, a second multi-focus parabolic mirror, as well as a beam splitter, a third multi-focus parabolic mirror, and a four-dimensional scanning frame. The device and method disclosed by the present invention can achieve three-dimensional tomography imaging with a micron-level resolution and component analysis with a hertz-level resolution for a sample to be measured, and at the same time have advantages such as a large dynamic range and good environmental adaptability.

Description

Technical Field

[0001] The present invention relates to the field of material defect detection and component analysis, and particularly to a reflection-type non-metallic material defect detection and component analysis device and method. Background Art

[0002] Terahertz electromagnetic waves have advantages such as fingerprint characteristics, low-energy safety, and strong penetrability, and are considered the preferred technology for realizing non-metallic material defect detection and component analysis. However, at present, most of the material defect detection and component analysis based on terahertz waves are based on terahertz time-domain spectroscopy (TDS) technology. Restricted by the signal generation mechanism, TDS signals have defects such as low power, small dynamic range, and poor environmental adaptability, and cannot meet the actual application requirements. The commonly used terahertz imaging and component analysis technology of electronics is restricted by the bandwidth limitation of the standard waveguide frequency band, and the imaging resolution cannot be guaranteed, and it also cannot meet the application requirements. Summary of the Invention

[0003] To solve the above technical problems, the present invention provides a reflection-type non-metallic material defect detection and component analysis device and method, which can realize three-dimensional tomographic imaging with a resolution of the order of micrometers for a sample to be measured and component analysis with a resolution of the order of hertz, and at the same time has advantages such as large dynamic range and good environmental adaptability.

[0004] To achieve the above object, the technical solution of the present invention is as follows:

[0005] A reflection-type non-metallic material defect detection and component analysis device includes a linearly frequency-modulated source module, a solid-state switch matrix, a low-noise amplifier module group, a terahertz signal transceiver device, an intermediate-frequency signal acquisition module, and a host computer that are connected in sequence; the terahertz signal transceiver device includes a first split-type terahertz signal transceiver integrated link group, a second split-type terahertz signal transceiver integrated link group, a first pair of terahertz antennas, a first transparent non-polarizing beam splitter, and a first multi-focus parabolic mirror arranged after the first split-type terahertz signal transceiver integrated link group, a second pair of terahertz antennas, a second transparent non-polarizing beam splitter, and a second multi-focus parabolic mirror arranged after the second split-type terahertz signal transceiver integrated link group, a beam splitter, a third multi-focus parabolic mirror, and a four-dimensional scanning frame for realizing the rotation of the sample to be measured arranged after the first multi-focus parabolic mirror and the second multi-focus parabolic mirror; a first visible laser emitter is arranged on one side of the first transparent non-polarizing beam splitter, and a second visible laser emitter is arranged on one side of the second transparent non-polarizing beam splitter.

[0006] In the above solution, the linearly frequency-modulated source module includes two output ports, both of which output a linearly frequency-modulated terahertz signal one and a linearly frequency-modulated terahertz signal two with a frequency range of 10 MHz to 26 GHz. The signals output from the two ports are of the same frequency and in the same phase, and are used as radio frequency signals and local oscillator signals respectively.

[0007] In the above solution, the solid-state switch matrix includes two input interfaces and M output interfaces, where M = 2×N and N is a positive integer; the two output ports of the chirp signal source module are respectively connected to the two input interfaces of the solid-state switch matrix, and the switching speed between the M output interfaces is on the order of ns to achieve fast switching between M channels.

[0008] In the above solution, the first split terahertz signal transceiver integrated link group includes 4 split terahertz signal transceiver integrated links, with frequency bands of 0.10 THz to 0.14 THz, 0.14 THz to 0.26 THz, 1.40 THz to 2.60 THz, and 2.60 THz to 4.0 THz respectively. The second split terahertz signal transceiver integrated link group includes 4 split terahertz signal transceiver integrated links, with frequency bands of 0.26 THz to 0.40 THz, 0.40 THz to 0.60 THz, 0.60 THz to 0.90 THz, and 0.90 THz to 1.40 THz respectively. Both link groups adopt the arrangement method with high frequency in the middle and low frequency at both ends.

[0009] In the above solution, the split terahertz signal transceiver integrated link includes a radio frequency signal input link and a local oscillator signal input link. The radio frequency signal input link adopts a signal output form combined with frequency multiplication and amplification, including a frequency multiplier one, an amplifier one, a frequency multiplier two, an amplifier two, a frequency multiplier three, a power divider one, and an amplifier three connected in sequence. Through a series of frequency multiplications and amplifications, a terahertz signal in a specific frequency band is radiated into free space; the function of the power divider one is to divide a path of the terahertz signal and input it into the D-th harmonic mixer one in the local oscillator signal input link; the local oscillator signal input link adopts a signal output form combined with frequency multiplication, amplification, and mixing, including a frequency multiplier four, an amplifier four, a frequency multiplier five, an amplifier five, a frequency multiplier six, an amplifier six, a power divider two, and the D-th harmonic mixer one connected in sequence. Through a series of frequency multiplications and amplifications, a terahertz signal in a specific frequency band is input into the D-th harmonic mixer one, and a reference signal is output after mixing; the function of the power divider two is to divide a path of the terahertz signal and input it into the D-th harmonic mixer two, and the terahertz signal reflected by the sample also enters the D-th harmonic mixer two, and the signal generated therefrom is obtained as a test signal through a low-noise amplifier.

[0010] In the above solution, both the first terahertz antenna pair and the second terahertz antenna pair include a transmitting antenna and a receiving antenna, and the transmitting antenna and the receiving antenna adopt terahertz corrugated horn antennas.

[0011] A method for detecting defects and analyzing components of a reflective non-metallic substance uses a device for detecting defects and analyzing components of a reflective non-metallic substance as described above, and includes the following steps:

[0012] Step 1: The linear frequency modulation source module outputs two linear frequency modulation microwave signals, which are used as the radio frequency signal and the local oscillator signal respectively. They are input into the solid-state switch matrix to achieve channel switching, and then enter the low-noise amplifier module group for signal amplification and DC component filtering.

[0013] Step 2: The processed microwave signals enter the first split terahertz signal transceiver integrated link group and the second split terahertz signal transceiver integrated link group respectively.

[0014] The radio frequency signal entering the first split terahertz signal transceiver integrated link group is frequency-multiplied and amplified in series, and then radiates terahertz signals in a specific frequency band into free space. After passing through the first terahertz antenna pair, the first transparent non-polarizing beam splitter, and the first multi-focus parabolic mirror, and then through the beam splitter and the third multi-focus parabolic mirror, it is focused on the surface of the sample to be measured and interacts with the sample to be measured. The terahertz signal containing the information of the sample to be measured returns along the original path and enters the first split terahertz signal transceiver integrated link group; the local oscillator signal entering the first split terahertz signal transceiver integrated link group is frequency-multiplied and amplified in series, mixed with part of the radio frequency signal, and then outputs a reference signal. The terahertz signal containing the information of the sample to be measured is mixed with part of the local oscillator signal to obtain a test signal.

[0015] The radio frequency signal entering the second split terahertz signal transceiver integrated link group is frequency-multiplied and amplified in series, and then radiates terahertz signals in a specific frequency band into free space. After passing through the second terahertz antenna pair, the second transparent non-polarizing beam splitter, and the second multi-focus parabolic mirror, and then through the beam splitter and the third multi-focus parabolic mirror, it is focused on the surface of the sample to be measured and interacts with the sample to be measured. The terahertz signal containing the information of the sample to be measured returns along the original path and enters the second split terahertz signal transceiver integrated link group; the local oscillator signal entering the second split terahertz signal transceiver integrated link group is frequency-multiplied and amplified in series, mixed with part of the radio frequency signal, and then outputs a reference signal. The terahertz signal containing the information of the sample to be measured is mixed with part of the local oscillator signal to obtain a test signal.

[0016] Step 3: The reference signals and test signals obtained by the first split terahertz signal transceiver integrated link group and the second split terahertz signal transceiver integrated link group are collected by the intermediate frequency signal acquisition module and uploaded to the upper computer. The defect detection and component analysis of the sample to be measured are realized by the signal processing algorithm built in the upper computer.

[0017] In a further technical solution, in step two, the first visible laser emitted by the first visible laser emitter is used to guide the laser for the links in the first split terahertz signal transceiver integrated link group through the first transparent non-polarizing beam splitter, so as to enable the terahertz signal to be accurately radiated to the surface of the sample to be measured and return along the original path; the second visible laser emitted by the second visible laser emitter is used to guide the laser for the links in the second split terahertz signal transceiver integrated link group through the second transparent non-polarizing beam splitter, so as to enable the terahertz signal to be accurately radiated to the surface of the sample to be measured and return along the original path.

[0018] In the above solution, the analysis method includes two working modes: broadband frequency modulation and refined frequency modulation.

[0019] In a further technical solution, the broadband frequency modulation working mode includes the following steps:

[0020] Step 1, parameter setting: including the stepped bandwidth of the linearly frequency modulated terahertz signal, signal power, scanning speed, test area, rotation angle interval and speed;

[0021] Step 2, place the metal plate on the four-dimensional scanning frame, and set the test area of the metal plate (X0, Y0, Z0, ⊙0)-(X e , Y e , Z e , ⊙ e ), so as to automatically position the metal plate to (X0, Y0, Z0, ⊙0);

[0022] Step 3, the linearly frequency modulated source module outputs a linearly frequency modulated terahertz signal, which passes through the solid-state switch matrix, the low-noise amplifier module group, and the terahertz signal transceiver device and is focused on the surface of the metal plate. It interacts with the metal plate, and the terahertz signal containing the metal plate information returns along the original path and is collected by the intermediate frequency signal acquisition module and uploaded to the upper computer;

[0023] Step 4, under the control of the software, first, with Z0 and ⊙0 unchanged, the amplitude and phase data of the metal plate in the area (X0, Y0)-(X e , Y e ) are collected; then, with ⊙0 unchanged, Z0 is moved to Z1, and the amplitude and phase data of the metal plate in the area (X0, Y0)-(X e , Y e ) are collected again, and so on until Z e is traversed and ended; ⊙0 is moved to ⊙1, and Z e is moved to Z0, and the amplitude and phase data of the metal plate in the area (X0, Y0)-(X e , Y e) Amplitude and phase data acquisition within; then keep ⊙1 unchanged, move Z0 to Z1, and again achieve amplitude and phase data acquisition of the metal plate within the region (X0, Y0)-(X e , Y e ), and so on until traversing to Z e ends; repeat the above operations until all amplitude and phase data acquisition from ⊙0 to ⊙ e is completed;

[0024] Step 5, remove the metal plate, place the sample to be measured on the four-dimensional scanning rack, and set the test area of the sample to be measured (X0, Y0, Z0, ⊙0)-(X e , Y e , Z e , ⊙ e ), to automatically position the sample to be measured to (X0, Y0, Z0, ⊙0);

[0025] Step 6, the chirp source module outputs a chirp terahertz signal, which passes through the solid-state switch matrix, the low-noise amplifier module group, and the terahertz signal transceiver device and is focused on the surface of the sample to be measured. It interacts with the sample to be measured, and the terahertz signal containing the information of the sample to be measured returns along the original path and is collected by the intermediate-frequency signal acquisition module and uploaded to the host computer;

[0026] Step 7, under the control of the software, repeat the operations in Step 4 to complete all amplitude and phase data acquisition of the sample to be measured;

[0027] Step 8, based on the amplitude and phase data of the terahertz signal reflected by the metal plate and the amplitude and phase data of the terahertz signal reflected by the sample to be measured, implement three-dimensional tomography imaging and rough analysis of the components of the sample to be measured based on the signal processing algorithms built in the host computer. The signal processing algorithms include three-dimensional tomography imaging algorithms, defect detection algorithms, and component rough estimation and analysis algorithms;

[0028] The refined frequency modulation working mode includes the following steps:

[0029] Step 9, in the broadband frequency modulation working mode, based on the obtained data, determine whether there is a characteristic peak in the sample to be measured. If there is no characteristic peak, stop executing; if there is a characteristic peak, continue with the subsequent operations;

[0030] Step 10, repeat the above Steps 1-Step 7;

[0031] Step 11, based on the amplitude and phase data of the terahertz signal reflected by the metal plate and the amplitude and phase data of the terahertz signal reflected by the sample to be measured, implement refined analysis of the components of the sample to be measured based on the component fine analysis algorithm built in the industrial control computer.

[0032] Through the above technical solutions, a reflection-type non-metallic material defect detection and component analysis device and method provided by the present invention have the following beneficial effects:

[0033] (1) Compared with a test system with separated transceiver, the present invention adopts a separated terahertz signal transceiver integrated link, which effectively reduces the system complexity on the premise of ensuring a large dynamic range;

[0034] (2) While realizing three-dimensional tomography imaging of a sample to be measured, the present invention can also achieve rough estimation and refined estimation of the components of the sample to be measured, which is more conducive to defect detection and classification of the sample to be measured;

[0035] (3) The present invention uses limited optical devices to achieve large-scale waveguide frequency band splicing, which is more conducive to system integration and has better environmental adaptability;

[0036] (4) The present invention helps to achieve efficient fusion of the spectra of the sample to be measured in a far-field environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0038] Figure 1 It is a schematic diagram of the module composition of a reflection-type non-metallic material defect detection and component analysis device disclosed in an embodiment of the present invention;

[0039] Figure 2 It is a schematic diagram of the specific structure composition of a reflection-type non-metallic material defect detection and component analysis device disclosed in an embodiment of the present invention;

[0040] Figure 3 It is a schematic diagram of the first separated terahertz signal transceiver integrated link group;

[0041] Figure 4 It is a schematic diagram of the second separated terahertz signal transceiver integrated link group;

[0042] Figure 5 It is a schematic diagram of the composition of the separated terahertz signal transceiver integrated link.

[0043] In the figure, 1 is a chirp source module; 2 is a solid-state switch matrix; 3 is a low-noise amplifier module group; 4 is an intermediate-frequency signal acquisition module; 5 is a host computer; 6 is a first split terahertz signal transceiver integrated link group; 7 is a second split terahertz signal transceiver integrated link group; 8 is a first terahertz antenna pair; 9 is a first transparent non-polarizing beam splitter; 10 is a first multi-focus parabolic mirror; 11 is a second terahertz antenna pair; 12 is a second transparent non-polarizing beam splitter; 13 is a second multi-focus parabolic mirror; 14 is a beam splitter; 15 is a third multi-focus parabolic mirror; 16 is a four-dimensional scanning frame; 17 is a sample to be measured; 18 is a first visible laser emitter; 19 is a second visible laser emitter. Detailed implementation manners

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0045] The present invention provides a reflection-type non-metallic material defect detection and component analysis device, as Figure 1 and Figure 2 shown, including a chirp source module 1, a solid-state switch matrix 2, a low-noise amplifier module group 3, a terahertz signal transceiver device, an intermediate-frequency signal acquisition module 4, and a host computer 5 that are connected in sequence.

[0046] The chirp source module 1 includes two output ports, both of which output a chirped microwave signal one and a chirped microwave signal two with a frequency range of 10 MHz to 26 GHz. The signals output from the two ports are of the same frequency and in-phase, and are used as the radio frequency signal and the local oscillator signal respectively.

[0047] The solid-state switch matrix 2 includes two input interfaces and M output interfaces, where M = 2×N, N is a positive integer, generally the number of split terahertz signal transceiver integrated links used during splicing. The switching speed between the M output interfaces is in the order of nanoseconds to achieve fast switching between M channels. The radio frequency signal output port of the chirp source module 1 is connected to the radio frequency signal input port of the solid-state switch matrix 2, and the local oscillator signal output port of the chirp source module 1 is connected to the local oscillator signal input port of the solid-state switch matrix 2; in this embodiment, there are 8 split terahertz signal transceiver integrated links in total. Therefore, the solid-state switch matrix has 16 output interfaces, including 8 radio frequency signal output ports and 8 local oscillator signal output ports, which correspond to 8 split terahertz signal transceiver integrated links one by one. When a certain split terahertz signal transceiver integrated link works, the solid-state switch matrix 2 switches to the corresponding output interface, and the chirp source module 1 outputs a chirped microwave signal with a frequency corresponding to the frequency band of this link.

[0048] The function of the low-noise amplifier module group 3 is to amplify M chirped terahertz signals and filter out the DC component at the same time.

[0049] As shown in Figure 2 the figure, the terahertz signal transceiver device includes a first split terahertz signal transceiver integrated link group 6, a second split terahertz signal transceiver integrated link group 7, a first terahertz antenna pair 8, a first transparent non-polarizing beam splitter 9, and a first multi-focus parabolic mirror 10 disposed after the first split terahertz signal transceiver integrated link group 6, a second terahertz antenna pair 11, a second transparent non-polarizing beam splitter 12, and a second multi-focus parabolic mirror 13 disposed after the second split terahertz signal transceiver integrated link group 7, a beam splitter 14, a third multi-focus parabolic mirror 15, and a four-dimensional scanning frame 16 for realizing the rotation of the sample to be measured 17 disposed after the first multi-focus parabolic mirror 10 and the second multi-focus parabolic mirror 13; a first visible laser transmitter 18 is disposed on one side of the first transparent non-polarizing beam splitter 9, and a second visible laser transmitter 19 is disposed on one side of the second transparent non-polarizing beam splitter 12.

[0050] In order to achieve three-dimensional structure imaging with a resolution on the micron scale, in the embodiments of the present invention, eight frequency bands of 0.10 THz to 0.14 THz, 0.14 THz to 0.26 THz, 0.26 THz to 0.40 THz, 0.40 THz to 0.60 THz, 0.60 THz to 0.90 THz, 0.90 THz to 1.40 THz, 1.40 THz to 2.60 THz, and 2.60 THz to 4.0 THz are adopted.

[0051] As shown in Figure 3 the figure, the first split terahertz signal transceiver integrated link group 6 includes 4 split terahertz signal transceiver integrated links, and the frequency bands are respectively 0.10 THz to 0.14 THz, 0.14 THz to 0.26 THz, 1.40 THz to 2.60 THz, and 2.60 THz to 4.0 THz. As shown in Figure 4 the figure, the second split terahertz signal transceiver integrated link group 7 includes 4 split terahertz signal transceiver integrated links, and the frequency bands are respectively 0.26 THz to 0.40 THz, 0.40 THz to 0.60 THz, 0.60 THz to 0.90 THz, and 0.90 THz to 1.40 THz. Both link groups adopt an arrangement method with high frequencies in the middle and low frequencies at both ends.

[0052] As shown in Figure 5As shown, the separated terahertz signal transceiver integrated link includes a radio frequency signal input link and a local oscillator signal input link. The radio frequency signal input link adopts a signal output form combined with frequency doubling and amplification, including a frequency multiplier 1, an amplifier 1, a frequency multiplier 2, an amplifier 2, a frequency multiplier 3, a power divider 1 and an amplifier 3 connected in sequence. After a series of frequency doubling and amplification, the terahertz signal of a specific frequency band is radiated into the free space; the function of the power divider 1 is to separate the terahertz signal into a D-th harmonic mixer 1 in the local oscillator signal input link; the local oscillator signal input link adopts The signal output form of the combination of frequency doubling, amplification and mixing includes a frequency multiplier 4, an amplifier 4, a frequency multiplier 5, an amplifier 5, a frequency multiplier 6, an amplifier 6, a power divider 2 and a D-th harmonic mixer 1 which are connected in sequence. After a series of frequency doubling and amplification, a terahertz signal of a specific frequency band is input into the D-th harmonic mixer 1, and a reference signal is output after mixing. The function of the power divider 2 is to split the terahertz signal into one path and input it into the D-th harmonic mixer 2. The terahertz signal reflected by the sample simultaneously enters the D-th harmonic mixer 2, and the signal generated thereby is passed through a low-noise amplifier to obtain a test signal.

[0053] The first terahertz antenna pair 8 and the second terahertz antenna pair 11 each include a transmitting antenna and a receiving antenna. In the present invention, in order to reduce transmission loss, the transmitting antenna and the receiving antenna are standard terahertz corrugated horn antennas.

[0054] The first visible laser emitted by the first visible laser emitter 18 passes through the first transparent non-polarizing beam splitter 9 to perform laser guidance for the link in the first separate terahertz signal transceiver integrated link group 6, so that the terahertz signal can be accurately radiated to the surface of the sample to be tested 17 and return along the original route; the second visible laser emitted by the second visible laser emitter 19 passes through the second transparent non-polarizing beam splitter 12 to perform laser guidance for the link in the second separate terahertz signal transceiver integrated link group 7, so that the terahertz signal can be accurately radiated to the surface of the sample to be tested 17 and return along the original route.

[0055] The function of the first multi-focal parabolic mirror 10 is to realize the collimation of terahertz signals of four frequency bands according to the input positions of the four frequency band links in the first separated terahertz signal transceiver integrated link group 6 .

[0056] The function of the second multi-focus parabolic mirror 13 is to realize the collimation of the terahertz signals of four frequency bands according to the input positions of the four frequency band links in the second separated terahertz signal transceiver integrated link group 7 .

[0057] The function of the third multi-focus parabolic mirror 15 is to simultaneously focus terahertz signals of eight frequency bands to the same position of the sample to be tested 17 .

[0058] The function of the beam splitter 14 is to enable the terahertz signals of 8 frequency bands to be radiated to the third multi-focus parabolic mirror 15. In the embodiment of the present invention, it is required that the thickness of the beam splitter 14 ≤ 0.4 mm.

[0059] The function of the four-dimensional scanning frame 16 is to enable the sample to be measured 17 to rotate in four directions of X-Y-Z-⊙, where ⊙ represents the rotation angle.

[0060] The function of the intermediate frequency signal acquisition module 4 is to achieve high-speed acquisition of 8 test signals and 8 reference signals, and transmit the acquired data to the host computer 5.

[0061] The function of the host computer 5 is to internally implement the program control of the hardware used in the entire system and the communication between the hardware through software; at the same time, it internally implements imaging and component analysis algorithms, and uses the discrete intermediate frequency signals to achieve three-dimensional tomography and component analysis of the sample to be measured 17.

[0062] The present invention provides a method for detecting defects and analyzing components of a reflective non-metallic substance. By using a device for detecting defects and analyzing components of a reflective non-metallic substance as described above, the working principle includes the following steps:

[0063] Step 1: The linear frequency modulation source module 1 outputs two linear frequency modulation microwave signals, which are used as the radio frequency signal and the local oscillator signal respectively, and are input into the solid-state switch matrix 2, and then enter the low-noise amplifier module group 3 for signal amplification and DC component filtering;

[0064] Step 2: The processed microwave signals enter the first split terahertz signal transceiver integrated link group 6 and the second split terahertz signal transceiver integrated link group 7 respectively;

[0065] The radio frequency signal entering the first split terahertz signal transceiver integrated link group 6 is multiplied in frequency and amplified in series, and then the terahertz signal of a specific frequency band is radiated into free space. After passing through the first terahertz antenna pair 8, the first transparent non-polarizing beam splitter 9, and the first multi-focus parabolic mirror 10, and then through the beam splitter 14 and the third multi-focus parabolic mirror 15, it is focused on the surface of the sample to be measured 17 and interacts with the sample to be measured 17. The terahertz signal containing the information of the sample to be measured 17 returns along the original path and enters the first split terahertz signal transceiver integrated link group 6; the local oscillator signal entering the first split terahertz signal transceiver integrated link group 6 is multiplied in frequency and amplified in series, and then mixed with part of the radio frequency signal to output a reference signal. The terahertz signal containing the information of the sample to be measured 17 is mixed with part of the local oscillator signal to obtain a test signal;

[0066] The radio frequency signal entering the second separated terahertz signal transceiver integrated link group 7 is radiated into free space as a terahertz signal in a specific frequency band after a series of frequency multiplications and amplifications. After passing through the second terahertz antenna pair 11, the second transparent non-polarizing beam splitter 12, and the second multi-focus parabolic mirror 13, it is then focused onto the surface of the sample to be measured 17 through the beam splitter 14 and the third multi-focus parabolic mirror 15, interacts with the sample to be measured 17, and the terahertz signal containing the information of the sample to be measured 17 returns along the original path and enters the second separated terahertz signal transceiver integrated link group 7; the local oscillator signal entering the second separated terahertz signal transceiver integrated link group 7 is mixed with part of the radio frequency signal after a series of frequency multiplications and amplifications to output a reference signal, and the terahertz signal containing the information of the sample to be measured 17 is mixed with part of the local oscillator signal to obtain a test signal;

[0067] Step 3: The reference signal and the test signal obtained by the first separated terahertz signal transceiver integrated link group 6 and the second separated terahertz signal transceiver integrated link group 7 are both collected by the intermediate frequency signal acquisition module 4 and uploaded to the host computer 5, and the defect detection and component analysis of the sample to be measured 17 are realized by the signal processing algorithm built in the host computer 5.

[0068] The above analysis method includes two working modes: wideband frequency modulation and fine frequency modulation in specific applications. Among them, the wideband frequency modulation working mode can achieve two functions: one is to realize high-resolution three-dimensional tomography of the sample to be measured 17, and further realize the defect detection of the interior and surface of the sample to be measured 17; the other is to realize the rough analysis of the components of the sample to be measured 17. The fine frequency modulation working mode realizes the fine analysis of the components of the sample to be measured 17 on the basis of the wideband frequency modulation working mode.

[0069] The wideband frequency modulation working mode includes the following steps:

[0070] Step 1: Parameter setting: including the stepped bandwidth of the linearly frequency-modulated terahertz signal (the stepped bandwidth is generally required to be ≥1 GHz in the wideband frequency modulation working mode), signal power, scanning speed, test area, rotation angle interval and speed;

[0071] Step 2: Place the metal plate on the four-dimensional scanning frame 16, and set the test area of the metal plate (X0, Y0, Z0, ⊙0)-(X e , Y e , Z e , ⊙ e ), to realize the automatic positioning of the metal plate to (X0, Y0, Z0, ⊙0);

[0072] Step 3: The linear frequency modulation source module 1 outputs a linear frequency modulation terahertz signal, which passes through the solid-state switch matrix 2, the low-noise amplifier module group 3, and the terahertz signal transceiver device and is focused on the surface of the metal plate. It interacts with the metal plate, and the terahertz signal containing the metal plate information returns along the original path and is collected by the intermediate-frequency signal acquisition module 4 and uploaded to the host computer 5.

[0073] Step 4: Under the control of the software, first, with Z0 and ⊙0 unchanged, the amplitude and phase data of the metal plate in the area (X0, Y0)-(X e , Y e ) are collected; then, with ⊙0 unchanged, Z0 is moved to Z1, and the amplitude and phase data of the metal plate in the area (X0, Y0)-(X e , Y e ) are collected again, and so on until Z e is traversed to the end; ⊙0 is moved to ⊙1, and Z e is moved to Z0, and the amplitude and phase data of the metal plate in the area (X0, Y0)-(X e , Y e ) are collected; then, with ⊙1 unchanged, Z0 is moved to Z1, and the amplitude and phase data of the metal plate in the area (X0, Y0)-(X e , Y e ) are collected again, and so on until Z e is traversed to the end; the above operations are repeated until all the amplitude and phase data from ⊙0 to ⊙ e are collected.

[0074] Step 5: The metal plate is removed, and the sample to be measured 17 is placed on the four-dimensional scanning rack 16. The test area of the sample to be measured 17 is set as (X0, Y0, Z0, ⊙0)-(X e , Y e , Z e , ⊙ e ), and the sample to be measured 17 is automatically positioned to (X0, Y0, Z0, ⊙0).

[0075] Step 6: The linear frequency modulation source module 1 outputs a linear frequency modulation terahertz signal, which passes through the solid-state switch matrix 2, the low-noise amplifier module group 3, and the terahertz signal transceiver device and is focused on the surface of the sample to be measured 17. It interacts with the sample to be measured 17, and the terahertz signal containing the sample to be measured 17 information returns along the original path and is collected by the intermediate-frequency signal acquisition module 4 and uploaded to the host computer 5.

[0076] Step 7: Under the control of the software, the operation in Step 4 is repeated to complete the acquisition of all the amplitude and phase data of the sample to be measured 17.

[0077] Step 8: Based on the amplitude-phase data of the terahertz signal reflected by the metal plate and the amplitude-phase data of the terahertz signal reflected by the sample to be measured 17, three-dimensional tomography and rough analysis of the components of the sample to be measured 17 are realized based on the signal processing algorithms built in the host computer 5. The signal processing algorithms include three-dimensional tomography algorithms, defect detection algorithms, and rough component estimation and analysis algorithms.

[0078] The refined frequency modulation working mode includes the following steps:

[0079] Step 9: In the wideband frequency modulation working mode, based on the obtained data, it is judged whether there is a characteristic peak in the sample to be measured 17. If there is no characteristic peak, the operation is not continued; if there is a characteristic peak, the subsequent operations are continued;

[0080] Step 10: Repeat the above Steps 1 - Step 7; among them, when setting parameters, the refined frequency modulation working mode generally requires a step bandwidth of 1 kHz, with the frequency information corresponding to the characteristic peak as the center frequency and within a 2 GHz bandwidth;

[0081] Step 11: Based on the amplitude-phase data of the terahertz signal reflected by the metal plate and the amplitude-phase data of the terahertz signal reflected by the sample to be measured 17, refined analysis of the components of the sample to be measured 17 is realized based on the component fine analysis algorithm built in the industrial control computer.

[0082] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A reflection type non-metallic substance defect detection and component analysis device, characterized in that, It includes a chirp source module, a solid-state switch matrix, a low-noise amplifier module group, a terahertz signal transceiver device, an intermediate-frequency signal acquisition module, and a host computer that are connected in sequence; the terahertz signal transceiver device includes a first split terahertz signal transceiver integrated link group, a second split terahertz signal transceiver integrated link group, a first terahertz antenna pair, a first transparent non-polarizing beam splitter, and a first multi-focus parabolic mirror arranged after the first split terahertz signal transceiver integrated link group, a second terahertz antenna pair, a second transparent non-polarizing beam splitter, and a second multi-focus parabolic mirror arranged after the second split terahertz signal transceiver integrated link group, a beam splitter, a third multi-focus parabolic mirror, and a four-dimensional scanning stage for realizing the rotation of the sample to be measured arranged after the first multi-focus parabolic mirror and the second multi-focus parabolic mirror; a first visible laser transmitter is arranged on one side of the first transparent non-polarizing beam splitter, and a second visible laser transmitter is arranged on one side of the second transparent non-polarizing beam splitter; The first split terahertz signal transceiver integrated link group includes 4 split terahertz signal transceiver integrated links with frequency bands of 0.10 THz to 0.14 THz, 0.14 THz to 0.26 THz, 1.40 THz to 2.60 THz, and 2.60 THz to 4.0 THz respectively. The second split terahertz signal transceiver integrated link group includes 4 split terahertz signal transceiver integrated links with frequency bands of 0.26 THz to 0.40 THz, 0.40 THz to 0.60 THz, 0.60 THz to 0.90 THz, and 0.90 THz to 1.40 THz respectively. Both link groups adopt an arrangement method with high frequencies in the middle and low frequencies at both ends; The split terahertz signal transceiver integrated link includes a radio frequency signal input link and a local oscillator signal input link. The radio frequency signal input link adopts a signal output form combined with frequency multiplication and amplification, and includes a frequency multiplier one, an amplifier one, a frequency multiplier two, an amplifier two, a frequency multiplier three, a power divider one, and an amplifier three that are connected in sequence. After a series of frequency multiplications and amplifications, the terahertz signal in a specific frequency band is radiated into free space; the function of the power divider one is to split a path of the terahertz signal and input it into a D-th harmonic mixer one in the local oscillator signal input link; the local oscillator signal input link adopts a signal output form combined with frequency multiplication, amplification, and mixing, and includes a frequency multiplier four, an amplifier four, a frequency multiplier five, an amplifier five, a frequency multiplier six, an amplifier six, a power divider two, and a D-th harmonic mixer one that are connected in sequence. After a series of frequency multiplications and amplifications, the terahertz signal in a specific frequency band is input into the D-th harmonic mixer one, and a reference signal is output after mixing; the function of the power divider two is to split a path of the terahertz signal and input it into a D-th harmonic mixer two, and the terahertz signal reflected by the sample also enters the D-th harmonic mixer two, and the signal generated therefrom is obtained as a test signal through a low-noise amplifier.

2. The reflection type non-metallic substance defect detection and component analysis device according to claim 1, wherein The chirp source module includes two output ports, both of which output a chirped terahertz signal 1 and a chirped terahertz signal 2 with a frequency range of 10 MHz to 26 GHz. The signals output from the two ports are of the same frequency and in phase, and are used as the RF signal and the local oscillator signal respectively.

3. The reflective non-metallic material defect detection and component analysis device according to claim 2, wherein, The solid-state switch matrix includes two input interfaces and M output interfaces, where M = 2×N and N is a positive integer. The two output ports of the chirp source module are respectively connected to the two input interfaces of the solid-state switch matrix. The switching speed between the M output interfaces is on the order of nanoseconds to achieve fast switching between M channels.

4. The reflective non-metallic material defect detection and component analysis device according to claim 1, characterized in that, Both the first terahertz antenna pair and the second terahertz antenna pair include a transmitting antenna and a receiving antenna, and the transmitting antenna and the receiving antenna adopt terahertz corrugated horn antennas.

5. A method for detecting defects and analyzing components of a reflective non-metallic substance, using a device for detecting defects and analyzing components of a reflective non-metallic substance as described in claim 1, characterized in that, It includes the following steps: Step 1: The chirp source module outputs two chirped microwave signals, which are used as the RF signal and the local oscillator signal respectively, and are input into the solid-state switch matrix to achieve channel switching, and then enter the low-noise amplifier module group for signal amplification and DC component filtering. Step 2: The processed microwave signals enter the first split terahertz signal transceiver integrated link group and the second split terahertz signal transceiver integrated link group respectively. The RF signal entering the first split terahertz signal transceiver integrated link group is frequency-multiplied and amplified in series, and then radiates a terahertz signal in a specific frequency band into free space. After passing through the first terahertz antenna pair, the first transparent non-polarizing beam splitter, and the first multi-focus parabolic mirror, it is then focused on the surface of the sample to be measured through the plane beam splitter and the third multi-focus parabolic mirror, interacts with the sample to be measured, and the terahertz signal containing the information of the sample to be measured returns along the original path and enters the first split terahertz signal transceiver integrated link group. The local oscillator signal entering the first split terahertz signal transceiver integrated link group is frequency-multiplied and amplified in series, mixed with part of the RF signal, and then outputs a reference signal. The terahertz signal containing the information of the sample to be measured is mixed with part of the local oscillator signal to obtain a test signal. The RF signal entering the second split terahertz signal transceiver integrated link group is frequency-multiplied and amplified in series, and then radiates a terahertz signal in a specific frequency band into free space. After passing through the second terahertz antenna pair, the second transparent non-polarizing beam splitter, and the second multi-focus parabolic mirror, it is then focused on the surface of the sample to be measured through the beam splitter and the third multi-focus parabolic mirror, interacts with the sample to be measured, and the terahertz signal containing the information of the sample to be measured returns along the original path and enters the second split terahertz signal transceiver integrated link group. The local oscillator signal entering the second split terahertz signal transceiver integrated link group is frequency-multiplied and amplified in series, mixed with part of the RF signal, and then outputs a reference signal. The terahertz signal containing the information of the sample to be measured is mixed with part of the local oscillator signal to obtain a test signal. Step 3: The reference signals and test signals obtained by the first split terahertz signal transceiver integrated link group and the second split terahertz signal transceiver integrated link group are collected by the intermediate frequency signal acquisition module and uploaded to the upper computer, and the defect detection and component analysis of the sample to be measured are realized by the signal processing algorithm built in the upper computer.

6. A method for detecting defects and analyzing components of a reflective non-metallic substance according to claim 5, characterized in that, In step 2, the first visible laser emitted by the first visible laser emitter is used to guide the laser for the links in the first split terahertz signal transceiver integrated link group through the first transparent non-polarizing beam splitter, so as to enable the terahertz signal to be accurately radiated to the surface of the sample to be measured and return along the original path; The second visible laser emitted by the second visible laser emitter is used to guide the laser for the links in the second split terahertz signal transceiver integrated link group through the second transparent non-polarizing beam splitter, so as to enable the terahertz signal to be accurately radiated to the surface of the sample to be measured and return along the original path.

7. A method for detecting defects and analyzing components of a reflective non-metallic substance according to claim 6, characterized in that, This analysis method includes two working modes: broadband frequency modulation and refined frequency modulation.

8. A method for detecting defects and analyzing components of a reflective non-metallic substance according to claim 7, characterized in that, The broadband frequency modulation working mode includes the following steps: Step 1, parameter setting: including the step bandwidth of the linearly frequency-modulated terahertz signal, signal power, scanning speed, test area, rotation angle interval and speed; Step 2: Place the metal plate on the four-dimensional scanning rack and set the test area of the metal plate as (X0, Y0, Z0, ⊙0)-(X e , Y e , Z e , ⊙ e ), so as to automatically position the metal plate at (X0, Y0, Z0, ⊙0); Step 3, the linearly frequency-modulated source module outputs a linearly frequency-modulated terahertz signal, which passes through the solid-state switch matrix, low-noise amplifier module group, and terahertz signal transceiver device and is focused on the surface of the metal plate. It interacts with the metal plate, and the terahertz signal containing the metal plate information returns along the original path and is collected by the intermediate-frequency signal acquisition module and uploaded to the host computer; Step 4, under the control of the software, first, with Z0 and ⊙0 unchanged, amplitude-phase data of the metal plate within the region (X0, Y0)-(X e , Y e ) is collected; then, with ⊙0 unchanged, Z0 is moved to Z1, and amplitude-phase data of the metal plate within the region (X0, Y0)-(X e , Y e ) is collected again, and so on until Z e is traversed; ⊙0 is moved to ⊙1, Z e is moved to Z0, and amplitude-phase data of the metal plate within the region (X0, Y0)-(X e , Y e ) is collected; then, with ⊙1 unchanged, Z0 is moved to Z1, and amplitude-phase data of the metal plate within the region (X0, Y0)-(X e , Y e ) is collected again, and so on until Z e is traversed; the above operations are repeated until all amplitude-phase data from ⊙0 to ⊙ e is collected; Step 5: Remove the metal plate, place the sample to be measured on the four-dimensional scanning rack, and set the test area of the sample to be measured (X0, Y0, Z0, ⊙0)-(X e , Y e , Z e , ⊙ e ), so as to automatically position the sample to be measured at (X0, Y0, Z0, ⊙0); Step 6, the linearly frequency-modulated source module outputs a linearly frequency-modulated terahertz signal, which passes through the solid-state switch matrix, low-noise amplifier module group, and terahertz signal transceiver device and is focused on the surface of the sample to be measured. It interacts with the sample to be measured, and the terahertz signal containing the information of the sample to be measured returns along the original path and is collected by the intermediate-frequency signal acquisition module and uploaded to the host computer; Step 7, under the control of the software, repeat the operation of step 4 to complete the acquisition of all amplitude-phase data of the sample to be measured; Step 8, based on the amplitude-phase data of the terahertz signal reflected by the metal plate and the amplitude-phase data of the terahertz signal reflected by the sample to be measured, realize the three-dimensional tomographic imaging of the sample to be measured and the rough analysis of the components based on the signal processing algorithms built in the host computer. The signal processing algorithms include three-dimensional tomographic imaging algorithms, defect detection algorithms, and component rough estimation analysis algorithms; The refined frequency modulation working mode includes the following steps: Step 9, in the broadband frequency modulation working mode, based on the obtained data, judge whether there is a characteristic peak in the sample to be measured. If there is no characteristic peak, stop executing; If there is a characteristic peak, continue to execute the subsequent operations; Step 10, repeat the above steps 1-step 7; Step 11, based on the amplitude-phase data of the terahertz signal reflected by the metal plate and the amplitude-phase data of the terahertz signal reflected by the sample to be measured, realize the refined analysis of the components of the sample to be measured based on the component fine analysis algorithm built in the industrial control computer.

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