CN110068858B

CN110068858B - Triaxial integrated electrochemical geophone based on MEMS

Info

Publication number: CN110068858B
Application number: CN201910405291.5A
Authority: CN
Inventors: 陈德勇; 齐文杰; 王军波; 许超; 郑希宸; 刘博文; 陈健
Original assignee: Institute of Electronics of CAS
Current assignee: Institute of Electronics of CAS
Priority date: 2019-05-15
Filing date: 2019-05-15
Publication date: 2020-12-18
Anticipated expiration: 2039-05-15
Also published as: CN110068858A

Abstract

The invention discloses a triaxial integrated electrochemical geophone based on MEMS, comprising: the shell is a regular hexahedron; the rubber films are respectively covered on each surface of the shell and form accommodating spaces with each surface; the first flow channel, the second flow channel and the third flow channel are mutually vertical and vertically penetrate through the surface of the shell; sensitive electrodes which are respectively arranged in the first flow channel, the second flow channel and the third flow channel; and electrolyte solution is filled in the sealing cavities formed by the first flow channel, the second flow channel, the third flow channel and the containing spaces respectively. The invention adopts a brand-new structural design, so that the orthogonality among three axial directions is more accurately ensured; and an auxiliary structure is not needed, the volume and the weight of the detector are reduced, meanwhile, a longer-length flow channel can be realized in the detector with the same volume, and the low-frequency performance of the detector is improved.

Description

Triaxial integrated electrochemical geophone based on MEMS

Technical Field

The invention relates to the technical field of MEMS geophones, in particular to a triaxial integrated electrochemical geophone based on MEMS.

Background

A geophone is a sensor that detects seismic waves and converts mechanical vibrations in the ground caused by the seismic waves into electrical signals. At present, geophones are widely applied to the fields of seismic monitoring, oil and gas exploration, building bridge detection, nuclear explosion detection and the like.

The components of seismic waves are very complex, and in practical application, a geophone needs to distinguish the characteristics of the seismic waves, such as the type, direction, size and the like, and identify detection information and interference information. The single-axis geophone can only detect seismic waves in one direction, and the obtained information is extremely limited; the three-axis geophone consists of three mutually perpendicular geophones, can simultaneously measure seismic waves in three basic axis directions, can detect longitudinal waves, transverse waves and converted waves, obtains richer seismic information and improves the accuracy of the detected information.

Common geophones include moving-coil geophones, capacitive-force balanced geophones, MEMS micro-accelerometers and the like. Compared with the above devices, the electrochemical geophone adopts the liquid mass block as the inertial mass, and has the advantages of large working inclination angle, good low-frequency performance, low cost and the like. The electrochemical geophone based on the MEMS technology adopts the MEMS technology to manufacture the sensitive electrode, and overcomes the defects of poor consistency, high alignment difficulty and high cost in the traditional platinum mesh weaving process. The existing triaxial electrochemical geophone consists of three uniaxial electrochemical geophones which are vertically arranged, and a stable and vertical support is generally welded on a substrate to ensure the vertical relation among the three geophones. The form is difficult to accurately ensure the orthogonality among the three detectors, and has overlarge volume, needs auxiliary structures and overlarge mass, thereby limiting the application range of the form.

Disclosure of Invention

Technical problem to be solved

The invention provides a triaxial integrated electrochemical geophone based on MEMS (micro-electromechanical systems), which at least solves part of technical problems.

(II) technical scheme

According to an aspect of the present invention, there is provided a MEMS-based triaxial integrated electrochemical geophone comprising:

the shell is a regular hexahedron;

the rubber films are respectively covered on each surface of the shell and form accommodating spaces with each surface;

the first flow channel, the second flow channel and the third flow channel are mutually vertical and vertically penetrate through the surface of the shell;

sensitive electrodes which are respectively arranged in the first flow channel, the second flow channel and the third flow channel;

and electrolyte solution is filled in the sealing cavities formed by the first flow channel, the second flow channel, the third flow channel and the containing spaces respectively.

In a further embodiment, the material of the housing is plexiglass.

In a further embodiment, the material of the rubber membrane is butyl rubber.

In further embodiments, the first flow channel, the second flow channel, and the third flow channel are independent of each other or are in communication with each other.

In a further embodiment, two sensing electrodes are symmetrically disposed in the first flow channel, the second flow channel, and the third flow channel, respectively.

In a further embodiment, the sensing electrode comprises:

a substrate layer;

the upper insulating layer and the lower insulating layer are respectively positioned at the upper end and the lower end of the substrate layer;

the anode is positioned at the upper end of the upper insulating layer;

and the cathode is positioned at the lower end of the lower insulating layer.

In a further embodiment, each of the sensitive electrodes is either an anode or a cathode on the side close to the rubber membrane.

In a further embodiment, the anode of the sensing electrode is applied with a voltage ranging between 0V and 1V.

In a further embodiment, the electrolyte solution has iodine and potassium iodide as solutes and glycerol, an ionic liquid or water as a solvent.

(III) advantageous effects

The invention provides a triaxial integrated electrochemical geophone based on MEMS, which at least has the following beneficial effects:

according to the invention, three mutually vertical flow channels which vertically penetrate through the surface of the shell are directly prepared and formed on the shell, so that the orthogonality among three axial directions is more accurately ensured, an auxiliary structure is not required for the detector, and the volume and the weight of the detector are reduced; and the design can realize a longer-length flow channel in the detector with the same volume, thereby improving the low-frequency performance of the detector.

Drawings

FIG. 1 is a longitudinal cross-sectional view of a MEMS-based triaxial integrated electrochemical geophone provided in accordance with the present invention.

FIG. 2 is a top view of a MEMS-based triaxial integrated electrochemical geophone provided in accordance with the present invention.

FIG. 3 is a schematic diagram of a cross-sectional structure of a sensitive electrode of the MEMS-based triaxial integrated electrochemical geophone provided by the invention.

Detailed Description

In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.

It should be noted that throughout the drawings, like elements are represented by like or similar reference numerals. In the following description, some specific embodiments are for illustrative purposes only and should not be construed as limiting the present invention in any way, but merely as exemplifications of embodiments of the invention. Conventional structures or constructions will be omitted when they may obscure the understanding of the present invention. It should be noted that the shapes and sizes of the respective components in the drawings do not reflect actual sizes and proportions, but merely illustrate the contents of the embodiments of the present invention.

Furthermore, the use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify a corresponding element is not intended to imply any ordinal numbers for the element, nor the order in which an element is sequenced or methods of manufacture, but are used to distinguish one element having a certain name from another element having a same name.

As shown in fig. 1 and fig. 2, fig. 1 and fig. 2 are a longitudinal cross-sectional view and a top view, respectively, of a three-axis integrated electrochemical geophone based on MEMS according to the present invention, which employs a completely new structural design to more accurately ensure orthogonality among three axes; and an auxiliary structure is not needed, the volume and the weight of the detector are reduced, meanwhile, a longer-length flow channel can be realized in the detector with the same volume, and the low-frequency performance of the detector is improved. The detector comprises:

the shell 1 is a regular hexahedron;

the rubber membranes 2 respectively cover all the surfaces of the shell 1 and respectively form accommodating spaces with all the surfaces;

the first flow channel 5, the second flow channel 6 and the third flow channel 7 are mutually vertical flow channels which vertically penetrate through the surface of the shell 1;

the sensitive electrode 3 is respectively arranged in the first flow channel 5, the second flow channel 6 and the third flow channel 7;

and the electrolyte solution 4 is respectively filled in the sealed cavities formed by the first flow channel 5, the second flow channel 6, the third flow channel 7 and the containing spaces.

In the present embodiment, the material of the housing 1 may be, but is not limited to, an organic material or a metal material; preferably, the material is organic glass.

In this embodiment, the rubber mold 2 is a circular structure with an outward protruding middle, and is sealed with the housing 1 by a steel ring in a mechanical compression manner. Wherein, the material of the rubber membrane 2 is butyl rubber.

In this embodiment, the first flow channel 5, the second flow channel 6 and the third flow channel 7 are independent or communicated with each other. The three flow channels are respectively vertical to the surface of the corresponding shell 1, and the design accurately ensures the orthogonality among the three axial directions. The rubber mold 2 and the shell 1 form an accommodating space and the corresponding runners form three mutually independent or mutually communicated sealed cavities.

In this embodiment, two sensing electrodes 3 are symmetrically disposed in the first flow channel 5, the second flow channel 6, and the third flow channel 7, respectively, and the sensing electrodes 3 may be symmetrically disposed on two sides of each flow channel, or may be disposed together on one side or in the middle of the flow channel. The sensitive electrode and the flow channel are sealed in a mechanical pressing mode through an O-shaped rubber ring.

As shown in fig. 3, fig. 3 is a schematic cross-sectional structure diagram of a sensing electrode of the MEMS-based triaxial integrated electrochemical geophone provided by the present invention, where the sensing electrode 3 includes:

a substrate layer 10;

the upper insulating layer 9 and the lower insulating layer 11 are respectively positioned at the upper end and the lower end of the substrate layer 10;

an anode 8 positioned at the upper end of the upper insulating layer 9;

and a cathode 12 positioned at the lower end of the lower insulating layer 11.

The manufacturing process of the sensitive electrode is as follows: firstly, thermally oxidizing a 200-micron silicon wafer to generate a layer of silicon oxide on the surface as an intermediate insulating layer, then sputtering and stripping the front surface to manufacture a front electrode layer, then deeply etching to generate array pores, and finally sputtering the back surface to generate a back electrode layer.

In this embodiment, the sensitive electrodes 3 are both anodes or both cathodes on the side close to the rubber membrane 2, that is, the voltage application mode of the four layers of electrodes in the same flow channel is cathode-anode-cathode or anode-cathode-anode. Wherein, the anode of the sensitive electrode 3 applies voltage in the range of 0V to 1V, and the cathode thereof applies zero voltage. Preferably, the voltage applied to the anode of the sensitive electrode 3 is 0.3V.

In this embodiment, the sealed cavity is filled with an electrolyte solution 4, solutes of the electrolyte solution 4 are iodine and potassium iodide, and a solvent is glycerol, an ionic liquid or water.

In this embodiment, the two rubber molds 2 in the x, y and z-axis directions and the mixed solution in the sealed cavity of the corresponding shaft form a vibration pickup structure, which can pick up the motion in the direction of the corresponding shaft.

The working principle of the invention is as follows: when the sensor moves in the x-axis direction, the vibration pickup structure in the x-axis direction can sense the movement in the x-axis direction, so that the solution in the x-axis channel generates corresponding flow, and the solution in the y-axis and z-axis directions cannot flow. The y-axis and z-axis work similar to the x-axis. When the cathode does not move, the electrolyte solution maintains an electrochemical equilibrium state, and the cathode outputs a direct current; the electrodes at both sides of the sensitive electrode respectively generate oxidation reaction and reduction reaction, thereby leading the I in the solution at both sides of the sensitive electrode₂The concentration generates larger difference, and the anode close to the rubber mold is enriched I₂And in the middle ofCathode I of₂And (4) lack. In the flow channel in the x-axis direction, when the liquid moves to the positive direction (right direction) of the x-axis, the sensing electrode on the left side of the x-axis brings a large amount of I due to the flow₂The reaction rate is accelerated, the output current of the cathode is increased, and the right sensitive electrode causes I due to flow₂The concentration is lower, so that the reaction rate is slowed down, and the output current of the cathode is reduced; the cathode currents of the two chips are processed to output an x-axis vibration waveform. The working modes of the y axis and the z axis are similar to the x axis. Wherein, the first flow channel 5, the second flow channel 6 and the third flow channel 7 represent the flow channels in the x-axis, the y-axis and the z-axis directions, respectively.

It is also noted that the illustrations herein may provide examples of parameters that include particular values, but that these parameters need not be exactly equal to the corresponding values, but may be approximated to the corresponding values within acceptable error tolerances or design constraints. Directional phrases used in the embodiments, such as "upper", "lower", "front", "rear", "left", "right", etc., refer only to the direction of the attached drawings and are not intended to limit the scope of the present invention. In addition, unless steps are specifically described or must occur in sequence, the order of the steps is not limited to that listed above and may be changed or rearranged as desired by the desired design. The above embodiments can be mixed and matched with each other or other embodiments based on design and reliability considerations, that is, the technical features of the different embodiments can be freely combined to form more embodiments

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A three-axis integrated electrochemical geophone based on MEMS, comprising:

the shell (1) is a regular hexahedron;

the rubber membranes (2) respectively cover all surfaces of the shell (1) and respectively form accommodating spaces with all the surfaces, and the rubber membranes (2) are of circular structures with the middle protruding outwards;

the first flow channel (5), the second flow channel (6) and the third flow channel (7) are mutually vertical flow channels which vertically penetrate through the surface of the shell (1), wherein the first flow channel (5), the second flow channel (6) and the third flow channel (7) are mutually communicated;

the sensitive electrodes (3) are respectively and at least partially arranged in the first flow channel (5), the second flow channel (6) and the third flow channel (7);

and electrolyte solution (4) is respectively filled in the sealed cavities formed by the first flow channel (5), the second flow channel (6), the third flow channel (7) and the containing spaces.

2. The MEMS-based triaxial integrated electrochemical geophone according to claim 1, wherein the material of the housing (1) is plexiglass.

3. The MEMS-based triaxial integrated electrochemical geophone according to claim 1, wherein the material of the rubber membrane (2) is butyl rubber.

4. The MEMS-based triaxial integrated electrochemical geophone according to claim 1, wherein two sensitive electrodes (3) are symmetrically placed in each of the first flow channel (5), the second flow channel (6) and the third flow channel (7).

5. The MEMS-based triaxial integrated electrochemical geophone according to claim 1 or 4, wherein the sensitive electrode (3) comprises:

a substrate layer (10);

the upper insulating layer (9) and the lower insulating layer (11) are respectively positioned at the upper end and the lower end of the substrate layer (10);

the anode (8) is positioned at the upper end of the upper insulating layer (9);

and the cathode (12) is positioned at the lower end of the lower insulating layer (11).

6. The MEMS-based triaxial integrated electrochemical geophone according to claim 5, wherein each of the sensitive electrodes (3) on the side close to the rubber membrane (2) is either an anode or a cathode.

7. The MEMS-based triaxial integrated electrochemical geophone according to claim 6, wherein the anode applied voltage of the sensitive electrode (3) ranges from 0V to 1V.

8. The MEMS-based triaxial integrated electrochemical geophone according to claim 1, wherein the electrolyte solution (4) has solutes of iodine and potassium iodide and the solvent is glycerol, ionic liquid or water.