High-sensitivity double-parameter self-decoupling strain sensor based on cross-shaped groove structure

Abstract

The invention relates to the technical field of surface acoustic wave strain sensors, in particular to a high-sensitivity double-parameter self-decoupling strain sensor based on a cross-shaped groove structure, which comprises a rectangular substrate, a longitudinal thinning groove is formed in the left side of the back surface of the rectangular substrate, and a transverse thinning groove is formed in the middle of the back surface of the rectangular substrate. The longitudinal thinning groove and the transverse thinning groove intersect to form a cross-shaped thinning groove, two pairs of interdigital electrodes, two lead electrodes and two pairs of surface acoustic wave reflecting gratings are prepared on the front face of the rectangular substrate, the first pair of interdigital electrodes is located above the longitudinal thinning groove and distributed front and back, and the second pair of interdigital electrodes is located above the transverse thinning groove and distributed back and forth. According to the surface acoustic wave strain sensor, the problems that an existing surface acoustic wave strain sensor is low in sensitivity and poor in strain measurement precision are effectively solved, and the surface acoustic wave strain sensor is suitable for the fields of structural health monitoring, mechanical performance testing, biomechanical research and the like.

Description

Technical Field

[0001] The invention relates to the technical field of surface acoustic wave strain sensors, in particular to a high-sensitivity dual-parameter self-decoupling strain sensor based on a cross-shaped groove structure. Background Art

[0002] Surface acoustic wave (SAW) strain sensors are widely used in structural health monitoring, mechanical performance testing, biomechanical research and other fields due to their advantages of small size, high quality factor and long-distance monitoring. However, in practical applications, the existing surface acoustic wave strain sensors have the following problems due to their own structural limitations: First, the existing surface acoustic wave strain sensors have poor response capabilities when measuring small strains (that is, the amount of their own strain is small when measuring small strains), which leads to low sensitivity. Second, the existing surface acoustic wave strain sensors cannot achieve self-decoupling of temperature and strain (that is, they cannot eliminate the interference of ambient temperature on the strain measurement results), which leads to poor strain measurement accuracy. Based on this, it is necessary to invent a high-sensitivity dual-parameter self-decoupling strain sensor based on a cross-slot structure to solve the problems of low sensitivity and poor strain measurement accuracy of existing surface acoustic wave strain sensors. Summary of the invention

[0003] In order to solve the problems of low sensitivity and poor strain measurement accuracy of existing surface acoustic wave strain sensors, the present invention provides a high-sensitivity dual-parameter self-decoupling strain sensor based on a cross-slot structure.

[0004] The present invention is achieved by adopting the following technical solutions:

[0005] A high-sensitivity dual-parameter self-decoupling strain sensor based on a cross-shaped groove structure comprises a rectangular base; the width direction of the rectangular base is the longitudinal direction, and the length direction is the transverse direction; a longitudinal thinning groove is opened on the left side of the back side of the rectangular base, and the two ends of the longitudinal thinning groove respectively penetrate the front and rear end surfaces of the rectangular base; a transverse thinning groove is opened in the center of the back side of the rectangular base, and the two ends of the transverse thinning groove respectively penetrate the left and right end surfaces of the rectangular base; the longitudinal thinning groove and the transverse thinning groove intersect to form a cross-shaped thinning groove;

[0006] Two pairs of interdigitated electrodes, two lead electrodes, and two pairs of surface acoustic wave reflection gratings are prepared on the front side of the rectangular substrate; the first pair of interdigitated electrodes is located above the longitudinal thinning groove, and the pair of interdigitated electrodes are distributed front to back; the second pair of interdigitated electrodes is located above the right part of the transverse thinning groove, and the pair of interdigitated electrodes are distributed left to right; the front interdigitated electrode in the first pair of interdigitated electrodes is connected to the left interdigitated electrode in the second pair of interdigitated electrodes through the first lead electrode; the rear interdigitated electrode in the first pair of interdigitated electrodes is connected to the right interdigitated electrode in the second pair of interdigitated electrodes through the second lead electrode; the first pair of surface acoustic wave reflection gratings are distributed left to right on the left and right sides of the first pair of interdigitated electrodes, and the length direction of the pair of surface acoustic wave reflection gratings is longitudinal; the second pair of surface acoustic wave reflection gratings are distributed front to back on the front and back sides of the second pair of interdigitated electrodes, and the length direction of the pair of surface acoustic wave reflection gratings is transverse.

[0007] Furthermore, the rectangular substrate is made of lanthanum gallium silicate; the two pairs of interdigitated electrodes, the two lead electrodes, and the two pairs of surface acoustic wave reflection gratings are all double-layer structures, the lower layer of which is a chromium adhesion layer and the upper layer of which is a platinum main layer.

[0008] Furthermore, longitudinal thinning grooves and transverse thinning grooves are opened on the back side of the rectangular substrate through photolithography and wet etching processes; two pairs of interdigitated electrodes, two lead electrodes, and two pairs of surface acoustic wave reflection gratings are prepared on the front side of the rectangular substrate through photolithography and sputtering processes.

[0009] Compared with the existing surface acoustic wave strain sensor, the high-sensitivity dual-parameter self-decoupling strain sensor based on the cross-groove structure described in the present invention has the following advantages: First, the present invention effectively enhances the response capability when measuring small strains by setting a cross-shaped thinning groove (that is, the self-strain amount is larger when measuring small strains), thereby effectively improving the sensitivity. Second, the present invention realizes the calculation of the strain amount by the differential method by setting two pairs of mutually orthogonal interdigitated electrodes, thereby realizing the self-decoupling of temperature and strain (that is, effectively eliminating the interference of ambient temperature on the strain measurement result), thereby effectively improving the strain measurement accuracy.

[0010] The present invention effectively solves the problems of low sensitivity and poor strain measurement accuracy of existing surface acoustic wave strain sensors, is suitable for fields such as structural health monitoring, mechanical property testing, and biomechanics research, and provides a new solution for improving the level of strain measurement technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a three-dimensional structural schematic diagram of the present invention.

[0012] Figure 2 yes Figure 1 Schematic diagram of part of the structure.

[0013] Figure 3 It is a schematic diagram of the three-dimensional structure from another angle of the present invention.

[0014] Figure 4 It is a schematic diagram of the planar structure of the present invention.

[0015] Figure 5 yes Figure 4 Left view of .

[0016] Figure 6 yes Figure 4 Top view of the .

[0017] Figure 7 yes Figure 4 Bottom view of .

[0018] Figure 8 It is a working state reference diagram of the present invention.

[0019] In the figure: 1- rectangular substrate, 101- longitudinal thinning groove, 102- transverse thinning groove, 201- interdigitated electrode, 202- lead electrode, 203- surface acoustic wave reflection grating, 3- object to be measured, 4- RF transceiver, 5- network analyzer; dotted line indicates wireless connection. DETAILED DESCRIPTION

[0020] A high-sensitivity dual-parameter self-decoupling strain sensor based on a cross-shaped groove structure comprises a rectangular substrate 1; the width direction of the rectangular substrate 1 is longitudinal, and the length direction is transverse; a longitudinal thinning groove 101 is opened on the left side of the back side of the rectangular substrate 1, and the two ends of the longitudinal thinning groove 101 respectively penetrate the front and rear end surfaces of the rectangular substrate 1; a transverse thinning groove 102 is opened in the center of the back side of the rectangular substrate 1, and the two ends of the transverse thinning groove 102 respectively penetrate the left and right end surfaces of the rectangular substrate 1; the longitudinal thinning groove 101 and the transverse thinning groove 102 cross to form a cross-shaped thinning groove;

[0021] Two pairs of interdigital electrodes 201, two lead electrodes 202, and two pairs of surface acoustic wave reflection gratings 203 are prepared on the front side of the rectangular substrate 1; the first pair of interdigital electrodes 201 is located above the longitudinal thinning groove 101, and the pair of interdigital electrodes 201 is distributed front to back; the second pair of interdigital electrodes 201 is located above the right part of the transverse thinning groove 102, and the pair of interdigital electrodes 201 is distributed left to right; the front interdigital electrode 201 in the first pair of interdigital electrodes 201 and the left interdigital electrode 201 in the second pair of interdigital electrodes 201 are connected through the first lead electrode The first pair of forked electrodes 201 is connected to the electrode 202; the forked electrode 201 at the rear in the first pair of forked electrodes 201 is connected to the forked electrode 201 at the right in the second pair of forked electrodes 201 through a second lead electrode 202; the first pair of surface acoustic wave reflection gratings 203 are distributed on the left and right sides of the first pair of forked electrodes 201, and the length directions of the pair of surface acoustic wave reflection gratings 203 are both longitudinal; the second pair of surface acoustic wave reflection gratings 203 are distributed on the front and back sides of the second pair of forked electrodes 201, and the length directions of the pair of surface acoustic wave reflection gratings 203 are both transverse.

[0022] The rectangular substrate 1 is made of lanthanum gallium silicate; the two pairs of interdigitated electrodes 201, the two lead electrodes 202, and the two pairs of surface acoustic wave reflection gratings 203 are all double-layer structures, with the lower layer being a chromium adhesion layer and the upper layer being a platinum main layer.

[0023] The longitudinal thinning groove 101 and the transverse thinning groove 102 are both opened on the back side of the rectangular substrate 1 by photolithography and wet etching processes; two pairs of interdigitated electrodes 201, two lead electrodes 202, and two pairs of surface acoustic wave reflection gratings 203 are all prepared on the front side of the rectangular substrate 1 by photolithography and sputtering processes.

[0024] During operation, the object to be measured 3, two RF transceivers 4, and a network analyzer 5 are selected respectively, the present invention is pasted to the stress concentration area of ​​the object to be measured 3, the two lead electrodes 202 are connected to the first RF transceiver 4, the first RF transceiver 4 is wirelessly connected to the second RF transceiver 4, and the second RF transceiver 4 is connected to the network analyzer 5.

[0025] The specific working process is as follows: First, the network analyzer 5 sends out an excitation signal, which is transmitted to the two pairs of interdigital electrodes 201 via the second RF transceiver 4, the first RF transceiver 4, and the two lead electrodes 202 in sequence, so that the two pairs of interdigital electrodes 201 resonate, thereby exciting two surface acoustic waves that propagate along the front of the rectangular substrate 1. After the two surface acoustic waves are reflected by the two pairs of surface acoustic wave reflection gratings 203, they are transmitted to the network analyzer 5 via the two pairs of interdigital electrodes 201, the two lead electrodes 202, the first RF transceiver 4, and the second RF transceiver 4 in sequence. The network analyzer 5 obtains the resonant frequency of the two pairs of interdigital electrodes 201 based on the two-path surface acoustic wave analysis. When the object 3 to be measured is strained, the present invention is strained accordingly, and the resonant frequency of the two pairs of interdigital electrodes 201 changes accordingly. At this time, the network analyzer 5 can calculate the strain amount using the differential method; the specific calculation formula is as follows:

[0026]

[0027] Where: f1, f2 represent the real-time resonant frequencies of the two pairs of interdigital electrodes 201 respectively; f 01 、f 02 represent the resonant frequencies of the two pairs of interdigital electrodes 201 at room temperature without strain, and f 01 、f 02 All are calibrated known quantities; S1 and S2 represent the strain sensitivities of the two pairs of interdigital electrodes 201 respectively, and both S1 and S2 are calibrated known quantities; ε represents the strain amount.

[0028] During specific implementation, the preparation steps of the present invention are as follows:

[0029] First, a rectangular substrate 1 is selected and cleaned, and then a longitudinal thinning groove 101 and a transverse thinning groove 102 are formed on the back of the rectangular substrate 1 by using a photolithography process and a wet etching process. The longitudinal thinning groove 101 and the transverse thinning groove 102 intersect to form a cross-shaped thinning groove;

[0030] Then, two pairs of interdigital electrodes 201, two lead electrodes 202, and two pairs of surface acoustic wave reflection gratings 203 are prepared on the front side of the rectangular substrate 1 by using photolithography and sputtering processes, thereby obtaining a high-sensitivity dual-parameter self-decoupling strain sensor based on a cross-groove structure.

[0031] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A high-sensitivity dual-parameter self-decoupling strain sensor based on a cross-slot structure, characterized in that: The invention comprises a rectangular base (1); the width direction of the rectangular base (1) is longitudinal and the length direction is transverse; a longitudinal thinning groove (101) is provided on the left side of the back side of the rectangular base (1), and the two ends of the longitudinal thinning groove (101) respectively penetrate the front and rear end surfaces of the rectangular base (1); a transverse thinning groove (102) is provided in the center of the back side of the rectangular base (1), and the two ends of the transverse thinning groove (102) respectively penetrate the left and right end surfaces of the rectangular base (1); the longitudinal thinning groove (101) and the transverse thinning groove (102) intersect to form a cross-shaped thinning groove; Two pairs of interdigital electrodes (201), two lead electrodes (202), and two pairs of surface acoustic wave reflection gratings (203) are prepared on the front side of a rectangular substrate (1); the first pair of interdigital electrodes (201) is located above a longitudinal thinning groove (101), and the pair of interdigital electrodes (201) are distributed front to back; the second pair of interdigital electrodes (201) is located above the right part of a transverse thinning groove (102), and the pair of interdigital electrodes (201) are distributed left to right; the interdigital electrodes (201) located in the front of the first pair of interdigital electrodes (201) and the interdigital electrodes (201) located in the left of the second pair of interdigital electrodes (201) are connected by a first lead electrode. The first pair of interdigitated electrodes (201) are connected to the first pair of interdigitated electrodes (201) by a line electrode (202); the interdigitated electrode (201) at the rear of the first pair of interdigitated electrodes (201) is connected to the interdigitated electrode (201) at the right of the second pair of interdigitated electrodes (201) by a second lead electrode (202); the first pair of surface acoustic wave reflection gratings (203) are distributed on the left and right sides of the first pair of interdigitated electrodes (201), and the length direction of the pair of surface acoustic wave reflection gratings (203) is longitudinal; the second pair of surface acoustic wave reflection gratings (203) are distributed on the front and back sides of the second pair of interdigitated electrodes (201), and the length direction of the pair of surface acoustic wave reflection gratings (203) is transverse.

2. According to claim 1, a high-sensitivity dual-parameter self-decoupling strain sensor based on a cross-slot structure is characterized by: The rectangular substrate (1) is made of lanthanum gallium silicate; the two pairs of interdigitated electrodes (201), the two lead electrodes (202), and the two pairs of surface acoustic wave reflection gratings (203) are all double-layer structures, the lower layer of which is a chromium adhesion layer and the upper layer of which is a platinum main body layer.

3. A high-sensitivity dual-parameter self-decoupling strain sensor based on a cross-slot structure according to claim 1 or 2, characterized in that: The longitudinal thinning groove (101) and the transverse thinning groove (102) are both opened on the back side of the rectangular substrate (1) by photolithography and wet etching processes; the two pairs of interdigital electrodes (201), the two lead electrodes (202), and the two pairs of surface acoustic wave reflection gratings (203) are both prepared on the front side of the rectangular substrate (1) by photolithography and sputtering processes.

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