Seismic geophone and measurement method thereof

Abstract

The present application belongs to the field of seismic exploration technology, and specifically discloses a seismic detector and its measurement method. The seismic detector includes a vibrator unit, an upper cover plate arranged parallel to and just above the vibrator unit, and a measuring unit; the lower surface of the upper cover plate is metal-deposited with a first capacitor plate array, and the upper surface of the vibrator of the vibrator unit is metal-deposited with a second capacitor plate array and a metal coil; the vibrator unit is set in a constant magnetic field, and the vibrator unit is electrically connected to the measuring unit; the vibrator unit is used to drive the second capacitor plate array to move relative to the first capacitor plate array when the vibrator moves due to external vibration, so as to generate a capacitance change signal; drive the metal coil to move to generate an induced current signal; the measuring unit is used to measure the seismic signal of the target frequency band based on the capacitance change signal and the induced current signal. Through the present application, seismic signal measurement covering a large dynamic range and a large frequency range can be achieved, while achieving high-resolution seismic signal measurement.

Description

Technical Field

[0001] The present application belongs to the field of seismic exploration technology, and more specifically, relates to a seismic geophone and a measurement method thereof. Background Art

[0002] Seismometers are instruments that measure the movement of the ground when it is disturbed. Measuring this ground motion with seismometers is often challenging due to the wide range of amplitudes and frequencies of earthquake signals.

[0003] At present, the commonly used seismic detector in the field of seismic exploration is the moving coil velocity detector. However, in the above-mentioned moving coil velocity detector, due to the limitation of its working principle, it can only record vibration signals above the natural frequency of its spring-oscillator system and is insensitive to lower frequency signals. Although it has high sensitivity, its typical dynamic range is only 60dB, which cannot detect larger vibration signals. Acceleration sensors are also commonly used for strong earthquake signal detection. According to their working principle, they can detect acceleration signals below their natural frequency, but their sensitivity is usually lower than that of moving coil velocity-type seismic detectors. Therefore, they are often used to detect strong vibrations. Therefore, using only moving coil velocity-type seismic detectors or acceleration-type seismic detectors cannot effectively measure seismic signals covering a large dynamic range and a large frequency range. Using the above two types of seismic detectors at the same time will inevitably increase costs.

[0004] Therefore, how to realize a single seismic detector that can simultaneously detect seismic signals covering a large dynamic range and a large frequency range is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0005] In view of the defects of the prior art, the purpose of the present application is to realize a single seismic detector that can simultaneously detect seismic signals covering a large dynamic range and a large frequency range.

[0006] To achieve the above objectives, in a first aspect, the present application provides a seismic detector, comprising:

[0007] A vibrator unit, an upper cover plate arranged parallel to and directly above the vibrator unit, and a measuring unit;

[0008] A first capacitor plate array is deposited on the lower surface of the upper cover plate, and a second capacitor plate array and a metal coil are deposited on the upper surface of the vibrator of the vibrator unit; the projections of the first capacitor plate array and the second capacitor plate array in the vertical direction completely overlap; the vibrator unit is placed in a constant magnetic field and is electrically connected to the measuring unit;

[0009] The vibrator unit is configured to drive the second capacitor plate array to move relative to the first capacitor plate array when the vibrator is subjected to external vibration and moves, thereby generating a capacitance change signal; and drive the metal coil to move, thereby generating an induced current signal;

[0010] The measuring unit is used to measure a seismic signal in a target frequency band based on the capacitance change signal and the induced current signal.

[0011] Optionally, the vibrator unit includes a test mass, a connecting beam, an outer frame, and a spring structure symmetrically distributed on both sides of the test mass; the test mass is connected to the spring structure through the connecting beam, and the spring structure is connected to the outer frame through the connecting beam; the vibrator is the test mass.

[0012] Optionally, the second capacitor plate array of the metal deposited on the upper surface of the proof mass of the vibrator unit is arranged inside the metal coil of the metal deposit.

[0013] Optionally, the geophone further comprises an upper yoke, an upper magnetic pole piece, a lower yoke and a lower magnetic pole piece;

[0014] The upper magnetic pole piece and the lower magnetic pole piece are arranged parallel and symmetrically above and below the vibrator unit, and the orthographic projections of the upper magnetic pole piece and the lower magnetic pole piece on the proof mass both cover the metal coil; the upper magnetic pole piece is arranged above the upper cover plate;

[0015] The upper yoke is arranged directly above the upper magnetic pole piece, and the lower yoke is arranged directly below the lower magnetic pole piece, and is used to control the magnetic field generated by the upper magnetic pole piece and the lower magnetic pole piece to pass vertically through the metal coil.

[0016] Optionally, the measurement unit includes a speed measurement unit, an acceleration measurement unit and a main control unit; the speed measurement unit and the acceleration measurement unit are respectively connected to the main control unit;

[0017] The speed measurement unit is used to analyze the induced current signal to determine a first digital signal corresponding to the speed information of the vibrator;

[0018] The acceleration measurement unit is used to analyze the capacitance change signal to determine a second digital signal corresponding to the acceleration information of the vibrator;

[0019] The main control unit is used to measure the seismic signal in the target frequency band based on the first digital signal and the second digital signal.

[0020] Optionally, the speed measurement unit includes a speed sensing subunit, a speed measurement and control circuit, and a first analog-to-digital converter;

[0021] The speed sensing subunit is used to convert the induced current signal into a corresponding first voltage change signal;

[0022] The speed measurement and control circuit is used to measure the speed analog signal of the vibrator based on the first voltage change signal;

[0023] The first analog-to-digital converter is used to convert the velocity analog signal of the vibrator into a corresponding first digital signal.

[0024] Optionally, the acceleration measurement unit includes an acceleration sensing subunit, an acceleration measurement and control circuit, and a second analog-to-digital converter;

[0025] The acceleration sensor subunit is used to convert the capacitance change signal into a corresponding second voltage change signal;

[0026] The acceleration measurement and control circuit is used to measure the acceleration analog signal of the vibrator based on the second voltage change signal;

[0027] The second analog-to-digital converter is used to convert the acceleration analog signal of the vibrator into a corresponding second digital signal.

[0028] In a second aspect, the present application further provides a measurement method applied to any of the aforementioned geophones, the method comprising:

[0029] When the vibrator unit is subjected to external vibration and the vibrator moves, a capacitance change signal and an induced current signal are simultaneously detected; the capacitance change signal is an induced signal generated by the vibrator driving the second capacitor plate array to move relative to the first capacitor plate array; the induced current signal is an induced signal generated by the vibrator driving the metal coil to move;

[0030] Analyzing the induced current signal to determine a first digital signal corresponding to the speed information of the vibrator;

[0031] Analyzing the capacitance change signal to determine a second digital signal corresponding to the acceleration information of the vibrator;

[0032] Based on the first digital signal and the second digital signal, a seismic signal in the target frequency band is measured.

[0033] Optionally, analyzing the induced current signal to determine the first digital signal corresponding to the speed information of the vibrator includes:

[0034] Converting the induced current signal into a corresponding first voltage change signal;

[0035] measuring a velocity analog signal of the vibrator based on the first voltage change signal;

[0036] The velocity analog signal of the vibrator is converted into a corresponding first digital signal.

[0037] Optionally, analyzing the capacitance change signal to determine the second digital signal corresponding to the acceleration information of the vibrator includes:

[0038] converting the capacitance change signal into a corresponding second voltage change signal;

[0039] measuring an acceleration analog signal of the vibrator based on the second voltage change signal;

[0040] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the existing technologies:

[0041] The present application provides a seismic detector and a measurement method thereof. Vibrator acceleration and velocity measurement mechanisms are integrated through micro-nano processing. A capacitor plate array and a metal coil are simultaneously metal-deposited on the vibrator of the vibrator unit, and a corresponding capacitor plate array is metal-deposited on the lower surface of the upper cover plate above it, forming a dual structure for capacitance displacement detection and induced current detection. This allows for simultaneous vibrator acceleration and velocity measurements on a single structure. The response frequency band can reach at least 0.01 Hz to 200 Hz, and the maximum dynamic range can reach 180 dB, enabling seismic signal measurement covering a large dynamic range and a large frequency range. Furthermore, the detector has high integration, a small size, and low cost. The bulk silicon penetration etching process can increase the weight of the inertial sensitive vibrator without increasing the chip thickness, thereby reducing mechanical thermal noise and improving the sensitivity of the vibrator acceleration to displacement, thereby achieving high-resolution seismic signal measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is one of the structural diagrams of the seismic detector provided in the embodiment of the present application;

[0043] Figure 2 This is a structural diagram of the upper cover plate in the seismic geophone provided in an embodiment of the present application;

[0044] Figure 3 Schematic diagram of the structure of the vibrator unit in the seismic detector provided in the embodiment of the present application;

[0045] Figure 4 This is the second structural diagram of the seismic detector provided in the embodiment of the present application;

[0046] Figure 5 1 is a schematic structural diagram of a measuring unit in a seismic geophone provided in an embodiment of the present application;

[0047] Figure 6 (a) is a schematic diagram of the amplitude-frequency response of the velocity measurement unit in the seismic geophone provided in an embodiment of the present application, and (b) is a schematic diagram of the amplitude-frequency response of the acceleration measurement unit in the seismic geophone provided in an embodiment of the present application;

[0048] Figure 7 1 is a flow chart of a method for measuring a seismic geophone provided in an embodiment of the present application;

[0049] Figure 8 It is a structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0051] The terms "first" and "second" in the specification and claims herein are used to distinguish different objects, rather than to describe a specific order of objects. For example, the terms "first capacitor plate array" and "second capacitor plate array" are used to distinguish different capacitor plate arrays, rather than to describe a specific order of the capacitor plate arrays; for another example, the terms "first analog-to-digital converter" and "second analog-to-digital converter" are used to distinguish analog-to-digital converters for different purposes, rather than to describe a specific order of the analog-to-digital converters.

[0052] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0053] In the description of the embodiments of the present application, unless otherwise specified, “plurality” means two or more than two. For example, “plurality” refers to two or more than two micro-capacitor plates.

[0054] It should be noted that the amplitude and frequency range of seismic signals are very large, with ground motion ranging from 0.1nm to a maximum of 10m, and a dynamic range of 220dB; the frequency range is from as low as 10 times the solid tide frequency. -5 Hz is extended to 1000Hz. Therefore, it is very difficult to develop an instrument that covers this large dynamic range and frequency range and achieves relatively high sensitivity. Therefore, in order to solve the above technical defects, the present application provides a seismic detector as described below.

[0055] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0056] Figure 1 This is one of the structural diagrams of the seismic detector provided in the embodiment of the present application, such as Figure 1 As shown, it is manufactured by a micro-electro-mechanical systems (MEMS) processing method. The seismic detector includes:

[0057] A vibrator unit 1, an upper cover plate 2 arranged parallel to and directly above the vibrator unit 1, and a measuring unit 3;

[0058] A first capacitor plate array 21 is deposited on the lower surface of the upper cover plate 2, and a second capacitor plate array 111 and a metal coil 112 are deposited on the upper surface of the vibrator 11 of the vibrator unit 1. The projections of the first capacitor plate array 21 and the second capacitor plate array 111 in the vertical direction completely overlap. The vibrator unit 1 is placed in a constant magnetic field and is electrically connected to the measuring unit 3.

[0059] The vibrator unit 1 is used to drive the second capacitor plate array 111 to move relative to the first capacitor plate array 21 to generate a capacitance change signal when the vibrator 11 moves due to external vibration, and drive the metal coil 112 to move to generate an induced current signal.

[0060] The measuring unit 3 is used to measure the seismic signal of the target frequency band based on the capacitance change signal and the induced current signal.

[0061] Specifically, the first capacitor plate array described in the embodiments of the present application refers to a capacitor plate array formed by metal deposition on the lower surface of the upper cover plate through a photolithography process, which can be composed of multiple micro-capacitor plates. The specific number of deposited micro-capacitor plates can be set according to actual design requirements.

[0062] The second capacitor plate array described in the embodiments of the present application refers to a capacitor plate array formed by metal deposition on the upper surface of the vibrator of the vibrator unit through a photolithography process, which can also be composed of multiple micro capacitor plates. The number of micro capacitor plates deposited in the second capacitor plate array is the same as or greater than that of the first capacitor plate array.

[0063] It should be noted that, in the embodiments of the present application, the vibrator unit and the upper cover plate may be made of a silicon substrate material covered with silicon dioxide.

[0064] The seismic signal of the target frequency band described in the embodiment of the present application refers to a seismic signal covering a low frequency band lower than the eigenfrequency of the vibrator unit and a high frequency band higher than the eigenfrequency of the vibrator unit.

[0065] In the embodiments of the present application, deep silicon etching can be used to penetrate the entire silicon wafer, thereby increasing the weight of the inertial sensitive vibrator without increasing the thickness of the chip, and depositing a second capacitor plate array and a metal coil on the upper surface of the vibrator unit. At the same time, a first capacitor plate array of the same size is also deposited on the lower surface of an upper cover plate arranged parallel to and directly above the vibrator unit, so that when the instrument is in a static state, the upper cover plate and the vibrator unit are both arranged horizontally, the first capacitor plate array and the second capacitor plate array are arranged opposite each other, and the projections of the first capacitor plate array and the second capacitor plate array in the vertical direction completely overlap, forming a capacitive displacement detection structure.

[0066] Figure 2 Schematic diagram of the structure of the upper cover plate in the seismic geophone provided in the embodiment of the present application. Figure 2 As shown, a first capacitor plate array 21 is deposited with metal at a specific location on the lower surface of the upper cover plate 2. This specific location can be determined based on the position of the second capacitor plate array on the vibrator inside the vibrator unit, as long as the first capacitor plate array and the second capacitor plate array are arranged directly opposite each other.

[0067] Furthermore, in an embodiment of the present application, the vibrator unit is placed in a constant magnetic field, and the magnetic field vertically passes through the metal coil on the surface of the vibrator unit, thereby forming an induced current detection structure.

[0068] Thus, when the geophone of the present embodiment is operating, when the vibrator unit is subjected to external vibrations that cause the internal vibrator to move, it can cause the capacitor plate array on the vibrator to shift relative to the capacitor plate array on the upper cover, thereby generating a capacitance change signal. Simultaneously, the moving vibrator also causes the metal coil to move in a constant magnetic field, causing the metal coil to cut through the magnetic flux lines, generating an induced electromotive force, and thus an induced current signal.

[0069] Furthermore, in an embodiment of the present application, a signal trace is formed by photolithography and metal deposition, and a signal output terminal can be set on the vibrator unit to electrically connect the vibrator unit to the measuring unit. In this way, the measuring unit can receive the capacitance change signal and the induced current signal generated by the movement of the vibrator unit in real time, and by performing vibrator acceleration measurement and analysis on the received capacitance change signal, it is possible to measure the seismic signal in the low frequency band below the eigenfrequency of the vibrator unit; by performing vibrator velocity measurement and analysis on the received induced current signal, it is possible to measure the seismic signal in the high frequency band above the eigenfrequency of the vibrator unit. Finally, based on the fusion and splicing processing of the two types of measurement result data, it is possible to measure the seismic signal of the target frequency band, and the response frequency band range can be at least 0.01Hz to 200Hz, and the maximum dynamic range can reach 180dB.

[0070] It should be noted that in the embodiments of the present application, by using integrated deep silicon etching to penetrate the entire silicon wafer, the weight of the inertial sensitive vibrator can be increased without increasing the thickness of the chip, thereby effectively reducing mechanical thermal noise and improving the sensitivity of the vibrator acceleration to displacement, achieving a higher resolution than existing MEMS seismic detectors or MEMS accelerometers, and the measurement resolution can reach 5ng.

[0071] In addition, in an embodiment of the present application, a MEMS processing method for manufacturing a metal coil and a capacitor plate array on a vibrator unit, as well as a signal jumper lead thereof, is provided. The specific steps are as follows:

[0072] Step 110 , transferring the signal trace pattern to the surface of a silicon substrate covered with silicon dioxide by a photolithography process, and evaporating metal to form a metal coil jumper trace;

[0073] Step 120, using physical vapor deposition (PECVD) technology to form a silicon dioxide film on the surface of the silicon substrate to cover the traces;

[0074] Step 130 , etching the silicon dioxide outside the metal traces using reactive ion etching (RIE) to open a window;

[0075] Step 140 , transfer the capacitor plate and metal coil patterns to the surface of the silicon substrate through a photolithography process, and evaporate and deposit metal to form a capacitor plate array and metal coil, and connect them to the metal traces in the window to complete the signal jumper lead-out.

[0076] The seismic detector of the embodiment of the present application integrates a vibrator acceleration and velocity measurement mechanism through micro-nano processing. A capacitor plate array and a metal coil are simultaneously metal-deposited on the vibrator of the vibrator unit, and a corresponding capacitor plate array is metal-deposited on the lower surface of the upper cover plate above it, forming a dual structure for capacitance displacement detection and induced current detection. Vibrator acceleration and velocity measurements can be performed simultaneously on a single structure. The response frequency band range can reach at least 0.01Hz to 200Hz, and the maximum dynamic range can reach 180dB, which can realize seismic signal measurement covering a large dynamic range and a large frequency range. At the same time, the detector has high integration, small size, and low cost. The bulk silicon penetration etching process can increase the weight of the inertial sensitive vibrator without increasing the chip thickness, thereby reducing mechanical thermal noise and improving the sensitivity of the vibrator acceleration to displacement, realizing high-resolution seismic signal measurement.

[0077] Figure 3 Schematic diagram of the structure of the vibrator unit in the seismic detector provided in the embodiment of the present application. Figure 3As shown, in the implementation of the present application, the vibrator unit 1 includes a test mass 11, a connecting beam 12, an outer frame 13, and a spring structure 14 symmetrically distributed on both sides of the test mass 11; the test mass 11 is connected to the spring structure 14 through the connecting beam 12, and the spring structure 14 is connected to the outer frame 13 through the connecting beam 12; the vibrator 11 is the test mass.

[0078] Specifically, in the embodiments of the present application, the internal structure of the vibrator unit is etched on a silicon substrate using a MEMS processing method. The spring structure is composed of etched folded beams, forming a hollow rectangular parallelepiped structure, and the spring expansion and contraction effect is achieved through the hollowed-out portion in the middle.

[0079] In the embodiments of the present application, the vibrator within the vibrator unit utilizes a proof mass. With spring structures symmetrically distributed on either side of the proof mass, one side of each spring structure is fixedly connected to the outer frame via a connecting beam, while the other side is connected to the proof mass via a connecting beam. This allows the proof mass to hover in the middle of the vibrator unit and move freely.

[0080] It should be noted that the sizes of the inspection mass, connecting beam, outer frame and spring structure in the vibrator unit can be set according to actual design requirements, and this application does not make specific restrictions on this.

[0081] The seismic detector of the embodiment of the present application constructs a vibrator unit by utilizing a test mass, a connecting beam, an outer frame and a spring structure. It has a simple structure and is easy to process. At the same time, it can effectively sense external ground vibrations and has high flexibility, which is conducive to improving the sensitivity of seismic wave perception.

[0082] Continue to refer to Figure 3 Based on the content of the above embodiment, as an optional embodiment, the second capacitor plate array 111 etched on the surface of the proof mass 11 of the vibrator unit 1 is set inside the deposited metal coil 112.

[0083] Specifically, in the embodiments of the present application, a second capacitor plate array and a metal coil are simultaneously deposited on the upper surface of the proof mass through micro-nanofabrication processes, wherein the second capacitor plate array is located within the metal coil. On the one hand, the second capacitor plate array provided on the proof mass and the second capacitor plate array provided on the bottom surface of the upper cover plate above it can form a capacitive displacement detection structure.

[0084] On the other hand, the vibrator unit is set in a preset constant magnetic field, so the test mass is also located in the constant magnetic field, which can make the constant magnetic field vertically pass through the metal coil deposited on the surface of the test mass, thereby forming an induced current detection structure.

[0085] The seismic detector of the embodiment of the present application can improve the utilization rate of the substrate material and save production costs while ensuring effective detection of the induced signal by simultaneously depositing a capacitor plate array and a metal coil on the surface of the inspection mass and etching the capacitor plate array inside the metal coil.

[0086] Figure 4 This is the second structural diagram of the seismic detector provided in the embodiment of the present application, such as Figure 4 As shown, as an optional embodiment, the seismic detector further includes an upper yoke 4, an upper magnetic pole piece 5, a lower yoke 6 and a lower magnetic pole piece 7;

[0087] The upper magnetic pole piece 5 and the lower magnetic pole piece 7 are arranged parallel and symmetrically above and below the vibrator unit 1, and the orthographic projections of the upper magnetic pole piece 5 and the lower magnetic pole piece 7 on the proof mass 11 both cover the metal coil 112; the upper magnetic pole piece 5 is provided on the upper surface of the upper cover plate 2;

[0088] The upper yoke 4 is arranged directly above the upper magnetic pole piece 5 , and the lower yoke 6 is arranged directly below the lower magnetic pole piece 7 , and is used to control the magnetic field generated by the upper magnetic pole piece 5 and the lower magnetic pole piece 7 to pass vertically through the metal coil 112 .

[0089] Specifically, in an embodiment of the present application, the seismic detector further includes a structural unit for generating a constant magnetic field, which specifically includes a pair of yokes and a pair of pole pieces, namely, an upper yoke, an upper pole piece, a lower yoke, and a lower pole piece. It is understood that the magnetic poles of the upper pole piece and the lower pole piece are opposite.

[0090] like Figure 4 As shown, in the embodiment of the present application, each magnetic pole piece includes two magnetic pole pieces, the upper magnetic pole piece and the lower magnetic pole piece are arranged symmetrically, and the upper magnetic pole piece is arranged above the upper cover plate and arranged parallel to the top of the vibrator unit, and the lower magnetic pole piece is arranged parallel to the bottom of the vibrator unit, and the positive projections of the upper magnetic pole piece and the lower magnetic pole piece on the inspection mass can completely cover the metal coil to ensure that the generated magnetic field can completely cover the metal coil on the inspection mass.

[0091] In the embodiment of this application, an upper yoke is positioned directly above the upper pole piece, and a lower yoke is positioned directly below the lower pole piece, forming a "sandwich" structure. The upper and lower yokes constrain the magnetic field, controlling the constant magnetic field generated by the upper and lower pole pieces to pass perpendicularly through the metal coil on the proof mass.

[0092] like Figure 4As shown, in an embodiment of the present application, the second capacitor plate array 111 on the inspection mass 11 and the first capacitor plate array 21 on the upper cover plate 2 constitute a parallel plate capacitor for measuring the displacement of the inspection mass 11 and thus measuring its acceleration. The upper yoke 4, the upper magnetic pole piece 5, the lower yoke 6 and the lower magnetic pole piece 7 are used to generate a constant magnetic field. When the inspection mass 11 moves, the metal coil 112 will cut the magnetic flux lines in the constant magnetic field to generate an induced current for detecting the speed of the inspection mass 11. It is only necessary to integrate the velocity signal once and the acceleration signal twice. Whether measuring acceleration or velocity, the purpose of measuring ground displacement can be achieved.

[0093] The seismic detector of the embodiment of the present application can stably output a constant magnetic field through the designed sandwich structure of the yoke iron and the magnetic pole piece, which facilitates the metal coil on the detection mass to cut the magnetic flux lines, which is beneficial to improving the stability of the speed measurement of the inspection mass and improving the resolution of high-frequency seismic signal detection.

[0094] Figure 5 Schematic diagram of the structure of the measuring unit in the seismic detector provided in the embodiment of the present application. Figure 5 As shown, the measuring unit 3 includes a speed measuring unit 31, an acceleration measuring unit 32 and a main control unit 33; the speed measuring unit 31 and the acceleration measuring unit 32 are respectively connected to the main control unit 33;

[0095] The speed measurement unit 31 is used to analyze the induced current signal to determine the first digital signal corresponding to the speed information of the vibrator;

[0096] The acceleration measurement unit 32 is used to analyze the capacitance change signal to determine the second digital signal corresponding to the acceleration information of the vibrator;

[0097] The main control unit 33 is used to measure the seismic signal of the target frequency band based on the first digital signal and the second digital signal.

[0098] Specifically, in the embodiment of the present application, the measurement unit can be mainly divided into three parts, including a speed measurement unit, an acceleration measurement unit and a main control unit. Among them, the speed measurement unit and the acceleration measurement unit are respectively connected to the main control unit for data communication.

[0099] In the embodiment of the present application, the speed measurement unit analyzes the induced current signal generated by the movement of the metal coil, determines the first digital signal corresponding to the speed information of the vibrator, and realizes the measurement of the vibrator speed.

[0100] Continue to refer to Figure 5 Based on the content of the above embodiment, as an optional embodiment, the speed measurement unit 31 includes a speed sensing subunit 311, a speed measurement and control circuit 312 and a first analog-to-digital converter 313;

[0101] The speed sensing subunit 311 is used to convert the induced current signal into a corresponding first voltage change signal;

[0102] The speed measurement and control circuit 312 is used to measure the speed analog signal of the vibrator based on the first voltage change signal;

[0103] The first analog-to-digital converter 313 is used to convert the velocity analog signal of the vibrator into a corresponding first digital signal.

[0104] Specifically, in an embodiment of the present application, the speed measurement unit includes a speed sensing subunit, a speed measurement and control circuit, and a first analog-to-digital converter. When the induced current signal generated by the metal coil is transmitted to the speed measurement unit, the speed sensing subunit first processes the induced current signal, i.e., converts the induced current signal into a corresponding voltage change signal, i.e., a first voltage change signal. The speed measurement and control circuit then performs a series of signal processing steps, including but not limited to bandpass filtering, modulation and demodulation, and low-pass filtering, to ultimately convert the voltage change signal into a final analog voltage output, i.e., obtain the vibrator's speed analog signal. The first analog-to-digital converter then further converts the vibrator's speed analog signal into a corresponding digital signal, i.e., a first digital signal, for transmission to the main control unit for processing.

[0105] In the embodiments of the present application, the vibrator may be a proof mass. For a metal coil, when the proof mass moves, the metal coil cuts the magnetic flux lines. According to Lenz's law, the relationship between the induced electromotive force E and the induced current I generated in the coil is as follows:

[0106] E = n2BLv;

[0107] I=E / R;

[0108] Where n2 represents the number of turns of the metal coil; B represents the magnetic induction intensity; L represents the length of the metal coil cutting the magnetic field line in the magnetic field, which is perpendicular to the Figure 3 The direction of movement is shown; v represents the speed of the test mass; and R represents the resistance of the metal coil.

[0109] In the embodiment of the present application, the speed measurement unit measures the induced current signal in the metal coil, thereby achieving the purpose of measuring the speed of the test mass. The yoke, magnetic pole piece, metal coil, speed sensor subunit, and speed measurement and control circuit constitute a speed transducer.

[0110] It should be noted that the velocity transducer can actually be considered as a second-order high-pass filter, and signals with frequencies lower than the eigenfrequency f0 of the vibrator unit will be filtered out. In this way, the velocity transducer can only measure relatively high-frequency seismic signals, but cannot measure low-frequency seismic signals.

[0111] The seismic detector of the embodiment of the present application constructs a velocity measurement unit by utilizing a velocity sensor unit, a velocity measurement and control circuit, and a first analog-to-digital converter, and combines the yoke, the pole piece, and the metal coil on the vibrator to form a velocity transducer. The vibrator has high sensitivity and can effectively measure the velocity changes of the vibrator, thereby realizing high-resolution measurement of high-frequency seismic signals.

[0112] Furthermore, in an embodiment of the present application, an acceleration measurement unit is used to analyze the capacitance change signal generated by the misalignment movement of the upper cover and the capacitor plate array on the vibrator, and a second digital signal corresponding to the acceleration information of the vibrator is determined to achieve the measurement of the vibrator acceleration.

[0113] Continue to refer to Figure 5 Based on the content of the above embodiment, as an optional embodiment, the acceleration measurement unit 32 includes an acceleration sensor subunit 321, an acceleration measurement and control circuit 322 and a second analog-to-digital converter 323;

[0114] The acceleration sensor subunit 321 is used to convert the capacitance change signal into a corresponding second voltage change signal;

[0115] The acceleration measurement and control circuit 322 is used to measure the acceleration analog signal of the vibrator based on the second voltage change signal;

[0116] The second analog-to-digital converter 323 is used to convert the acceleration analog signal of the vibrator into a corresponding second digital signal.

[0117] Specifically, in an embodiment of the present application, the acceleration measurement unit includes an acceleration sensor subunit, an acceleration measurement and control circuit, and a second analog-to-digital converter. When the capacitance change signal generated by the two capacitor plate arrays is transmitted to the acceleration measurement unit, the acceleration sensor subunit first processes the capacitance change signal, that is, converts the capacitance change signal into a corresponding voltage change signal, i.e., a second voltage change signal; the acceleration measurement and control circuit, through a series of signal processing steps, including but not limited to bandpass filtering, modulation and demodulation, low-pass filtering, etc., ultimately converts the above-mentioned voltage change signal into a final analog voltage output, i.e., obtains the acceleration analog signal of the vibrator; the second analog-to-digital converter further converts the acceleration analog signal of the vibrator into a corresponding digital signal, i.e., a second digital signal, and transmits the digital signal to the main control unit for processing.

[0118] In the embodiments of the present application, the vibrator may be a proof mass. When the proof mass moves, according to Newton's second law, the relationship between the acceleration change and the displacement of the proof mass, the relationship between the capacitance change and the displacement change, and the relationship between the voltage change and the capacitance change can be expressed as follows:

[0119] Δx=Δa / ω0 2 ;

[0120] ΔC=2n1εlΔx / d;

[0121] ΔV=V f ΔC / C f ;

[0122] Where Δx represents the displacement of the test mass; Δa represents the change in gravitational acceleration; ω0 represents the eigenfrequency of the vibrator unit; ΔC represents the capacitance change; n1 represents the number of facing plates in the first capacitor plate array and the second capacitor plate array; ε represents the dielectric constant; l represents the plate length; d represents the distance between the facing plates; V f Indicates the carrier amplitude; ΔV indicates the voltage change; C f Represents the feedback capacitor.

[0123] When the seismic detector is subjected to ground vibrations, causing the proof mass to move, the overlapping area of ​​the capacitors formed by the capacitor plate array on the upper cover and the capacitor plate array on the proof mass changes. The acceleration measurement unit measures this capacitance change, thereby measuring the acceleration change of the proof mass. The vibrator unit, the first capacitor plate array, the second capacitor plate array, the subsequent acceleration sensor subunit, and the acceleration measurement and control circuit constitute the acceleration transducer.

[0124] It should be noted that for the acceleration transducer, its open-loop working mode can be regarded as a second-order low-pass filter, which can measure relatively low-frequency seismic signals, while seismic signals with frequencies higher than the eigenfrequency f0 of the vibrator unit will be attenuated, making it impossible to measure high-frequency seismic signals.

[0125] The seismic detector of the embodiment of the present application constructs an acceleration measurement unit by utilizing an acceleration sensor sub-unit, an acceleration measurement and control circuit, and a second analog-to-digital converter, and combines a vibrator unit, a first capacitor plate array, and a second capacitor plate array to form an acceleration transducer. It can effectively measure the acceleration changes of the vibrator and achieve high-resolution measurement of low-frequency seismic signals.

[0126] Furthermore, in an embodiment of the present application, the main control unit is used to perform data fusion on the measurement results of the aforementioned velocity measurement unit and acceleration measurement unit, and the acceleration signal with a frequency lower than the eigenfrequency f0 of the vibrator unit is spliced ​​with the velocity signal with a frequency higher than the eigenfrequency f0 of the vibrator unit to realize the measurement of the wide-band seismic signal of the seismic detector.

[0127] Figure 6(a) is a schematic diagram of the amplitude-frequency response of the velocity measurement unit in the seismic detector provided in an embodiment of the present application, and (b) is a schematic diagram of the amplitude-frequency response of the acceleration measurement unit in the seismic detector provided in an embodiment of the present application. It can be seen from the figure that the frequency response of the velocity signal with a frequency higher than the eigenfrequency f0 of the vibrator unit and the acceleration signal with a frequency lower than the eigenfrequency f0 of the vibrator unit are flat in their respective frequency bands. Through signal fusion and splicing, the measurement of wide-band seismic signals of the seismic detector can be realized.

[0128] The seismic detector of the embodiment of the present application divides acceleration and velocity measurements into two channels for detection, which are independent of each other. The measurement data of the two channels are output in digital form after data fusion operation by the main control unit. The measurement results can cover the low frequency band below the eigenfrequency f0 of the vibrator unit and the high frequency band above the eigenfrequency f0 of the vibrator unit. The measurement frequency range is wide, and it is a large-scale, low-cost solution that can be implemented in the field of seismic exploration.

[0129] The measurement method of the seismic geophone provided in the present application is described below. The measurement method of the seismic geophone described below can be referenced to the seismic geophone described above.

[0130] Figure 7 is a flow chart of a method for measuring a seismic detector provided in an embodiment of the present application, which can be applied to any of the aforementioned seismic detectors, such as Figure 7 As shown, the method includes:

[0131] Step S1, when the vibrator unit is subjected to external vibration and the vibrator moves, simultaneously detecting a capacitance change signal and an induced current signal; the capacitance change signal is an induced signal generated by the vibrator driving the second capacitor plate array to move relative to the first capacitor plate array; the induced current signal is an induced signal generated by the vibrator driving the metal coil to move;

[0132] Step S2, analyzing the induced current signal to determine a first digital signal corresponding to the speed information of the vibrator;

[0133] Step S3, analyzing the capacitance change signal to determine a second digital signal corresponding to the acceleration information of the vibrator;

[0134] Step S4: measuring a seismic signal in a target frequency band based on the first digital signal and the second digital signal.

[0135] Based on the content of the above embodiment, as an optional embodiment, analyzing the induced current signal to determine the first digital signal corresponding to the speed information of the vibrator includes:

[0136] Converting the induced current signal into a corresponding first voltage change signal;

[0137] measuring a velocity analog signal of the vibrator based on the first voltage change signal;

[0138] The velocity analog signal of the vibrator is converted into a corresponding first digital signal.

[0139] Based on the content of the above embodiment, as an optional embodiment, analyzing the capacitance change signal to determine the second digital signal corresponding to the acceleration information of the vibrator includes:

[0140] converting the capacitance change signal into a corresponding second voltage change signal;

[0141] measuring an acceleration analog signal of the vibrator based on the second voltage change signal;

[0142] The acceleration analog signal of the vibrator is converted into a corresponding second digital signal.

[0143] It should be understood that the above method is applied to execute the seismic detector in the above embodiment. The implementation principle and technical effect of the method are similar to those described in the above seismic detector embodiment. The execution process of the method can refer to the corresponding measurement process in the above seismic detector embodiment, which will not be repeated here.

[0144] The measurement method of the seismic detector of the embodiment of the present application integrates the vibrator acceleration and velocity measurement mechanism through micro-nano processing, simultaneously metal-deposits a capacitor plate array and a metal coil on the vibrator of the vibrator unit, and deposits a corresponding capacitor plate array on the lower surface of the upper cover plate above it, forming a dual structure of capacitance displacement detection and induced current detection, so that the vibrator acceleration and velocity measurements can be performed simultaneously on a set of structures. The response frequency band range can reach at least 0.01Hz to 200Hz, and the maximum dynamic range can reach 180dB, which can realize seismic signal measurement covering a large dynamic range and a large frequency range. At the same time, the detector has high integration, small size, and low cost. The bulk silicon penetration etching process can increase the weight of the inertial sensitive vibrator without increasing the chip thickness, thereby reducing mechanical thermal noise and improving the sensitivity of the vibrator acceleration to displacement, thereby realizing high-resolution seismic signal measurement.

[0145] Based on the method in the above embodiment, the embodiment of the present application provides an electronic device, such as Figure 8 As shown, the electronic device may include: a processor (Processor) 810, a communication interface (CommunicationsInterface) 820, a memory (Memory) 830 and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other via the communication bus 840. The processor 810 can call the logic instructions in the memory 830 to execute the method in the above embodiment.

[0146] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application.

[0147] Based on the method in the above embodiment, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the method in the above embodiment.

[0148] Based on the method in the above embodiment, an embodiment of the present application provides a computer program product. When the computer program product runs on a processor, the processor executes the method in the above embodiment.

[0149] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0150] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, mobile hard disks, CD-ROMs or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC.

[0151] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted via the computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0152] It will be understood that the various numerical numbers involved in the embodiments of the present application are merely distinctions for the convenience of description and are not intended to limit the scope of the embodiments of the present application.

[0153] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0154] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the two are connected to each other and the relative position relationship after the connection remains unchanged. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after the connection. "Sliding connection" means that the two are connected to each other and can slide relative to each other after the connection. The directional terms mentioned in the embodiments of the present application, such as "up", "down", "inside", "outside", "left", "right", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0155] In addition, in the embodiments of the present application, the mathematical concepts mentioned are symmetry, equality, parallelism, and perpendicularity. These limitations are all in terms of the current technological level, rather than being absolutely strict definitions in the mathematical sense. A small amount of deviation is allowed, and approximate symmetry, approximate equality, approximate parallelism, and approximate perpendicularity are all acceptable. For example, the upper cover plate is parallel to the vibrator unit, which means that the upper cover plate and the vibrator unit are parallel or approximately parallel, and the angle between the upper cover plate and the vibrator unit can be between 0 degrees and 10 degrees. The direction of the magnetic field is perpendicular to the plane where the metal coil is located, which means that the direction of the magnetic field is perpendicular or approximately perpendicular to the plane where the metal coil is located, and the angle between them can be between 80 degrees and 100 degrees.

[0156] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A seismic geophone, characterized in that: include: A vibrator unit, an upper cover plate arranged parallel to and directly above the vibrator unit, and a measuring unit; A first capacitor plate array is deposited on the lower surface of the upper cover plate, and a second capacitor plate array and a metal coil are deposited on the upper surface of the vibrator of the vibrator unit; the projections of the first capacitor plate array and the second capacitor plate array in the vertical direction completely overlap; the vibrator unit is placed in a constant magnetic field and is electrically connected to the measuring unit; The vibrator unit is configured to drive the second capacitor plate array to move relative to the first capacitor plate array when the vibrator is subjected to external vibration and moves, thereby generating a capacitance change signal; and drive the metal coil to move, thereby generating an induced current signal; The measuring unit is used to measure a seismic signal in a target frequency band based on the capacitance change signal and the induced current signal.

2. The seismic detector according to claim 1, characterized in that The vibrator unit includes a test mass, a connecting beam, an outer frame, and a spring structure symmetrically distributed on both sides of the test mass; the test mass is connected to the spring structure through the connecting beam, and the spring structure is connected to the outer frame through the connecting beam; the vibrator is the test mass.

3. The seismic detector according to claim 2, characterized in that The second capacitor plate array of the metal deposited on the upper surface of the inspection mass of the vibrator unit is arranged inside the metal coil of the metal deposition.

4. The seismic detector according to claim 2, wherein: The seismic detector further comprises an upper yoke, an upper magnetic pole piece, a lower yoke and a lower magnetic pole piece; The upper magnetic pole piece and the lower magnetic pole piece are arranged parallel and symmetrically above and below the vibrator unit, and the orthographic projections of the upper magnetic pole piece and the lower magnetic pole piece on the proof mass both cover the metal coil; the upper magnetic pole piece is arranged above the upper cover plate; The upper yoke is arranged directly above the upper magnetic pole piece, and the lower yoke is arranged directly below the lower magnetic pole piece, and is used to control the magnetic field generated by the upper magnetic pole piece and the lower magnetic pole piece to pass vertically through the metal coil.

5. The seismic geophone according to any one of claims 1 to 4, characterized in that: The measuring unit includes a speed measuring unit, an acceleration measuring unit and a main control unit; the speed measuring unit and the acceleration measuring unit are respectively connected to the main control unit; The speed measurement unit is used to analyze the induced current signal to determine a first digital signal corresponding to the speed information of the vibrator; The acceleration measurement unit is used to analyze the capacitance change signal to determine a second digital signal corresponding to the acceleration information of the vibrator; The main control unit is used to measure the seismic signal in the target frequency band based on the first digital signal and the second digital signal.

6. The seismic detector according to claim 5, characterized in that The speed measurement unit includes a speed sensing subunit, a speed measurement and control circuit and a first analog-to-digital converter; The speed sensing subunit is used to convert the induced current signal into a corresponding first voltage change signal; The speed measurement and control circuit is used to measure the speed analog signal of the vibrator based on the first voltage change signal; The first analog-to-digital converter is used to convert the velocity analog signal of the vibrator into a corresponding first digital signal.

7. The seismic detector according to claim 5, characterized in that The acceleration measurement unit includes an acceleration sensor subunit, an acceleration measurement and control circuit and a second analog-to-digital converter; The acceleration sensor subunit is used to convert the capacitance change signal into a corresponding second voltage change signal; The acceleration measurement and control circuit is used to measure the acceleration analog signal of the vibrator based on the second voltage change signal; The second analog-to-digital converter is used to convert the acceleration analog signal of the vibrator into a corresponding second digital signal.

8. A measurement method applied to the seismic geophone according to any one of claims 1 to 7, characterized in that: The measuring method comprises: When the vibrator unit is subjected to external vibration and the vibrator moves, a capacitance change signal and an induced current signal are simultaneously detected; the capacitance change signal is an induced signal generated by the vibrator driving the second capacitor plate array to move relative to the first capacitor plate array; the induced current signal is an induced signal generated by the vibrator driving the metal coil to move; Analyzing the induced current signal to determine a first digital signal corresponding to the speed information of the vibrator; Analyzing the capacitance change signal to determine a second digital signal corresponding to the acceleration information of the vibrator; Based on the first digital signal and the second digital signal, a seismic signal in the target frequency band is measured.

9. The measuring method according to claim 8, characterized in that The analyzing the induced current signal to determine the first digital signal corresponding to the speed information of the vibrator includes: Converting the induced current signal into a corresponding first voltage change signal; measuring a velocity analog signal of the vibrator based on the first voltage change signal; The velocity analog signal of the vibrator is converted into a corresponding first digital signal.

10. The measuring method according to claim 8, characterized in that The analyzing the capacitance change signal to determine the second digital signal corresponding to the acceleration information of the vibrator includes: converting the capacitance change signal into a corresponding second voltage change signal; measuring an acceleration analog signal of the vibrator based on the second voltage change signal; The acceleration analog signal of the vibrator is converted into a corresponding second digital signal.

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