阅读说明：本技术 用于弹性体应变测量的薄膜应变计及制备方法 (Thin film strain gauge for elastomer strain measurement and preparation method thereof ) 是由 齐红丽 吴昊 马相龙 吴承勇 林杰俊 于 2019-11-21 设计创作，主要内容包括：本发明涉及一种用于弹性体应变测量的薄膜应变计及制备方法,该薄膜应变计中的绝缘隔离层、应变敏感层和保护层均制备于弹性体上,其中,绝缘隔离层制备于弹性体表面,用于薄膜应变计整体与弹性合金之间的电气绝缘；应变敏感层制备于所述绝缘隔离层上方,用于应变的测量；所述保护层制备于所属应变敏感层之上,并设置露出应变敏感层的引线电极,用于保护应变敏感层不受外界环境的影响,避免应变敏感层发生老化、腐蚀等现象。本发明的薄膜应变计,不同于传统粘贴式电阻应变片,不需要引入粘贴剂,从而避免了滞后与蠕变大的问题,并具有结构简单、精准度高、响应速度快的优点,制备好薄膜应变计的弹性体更可以满足其他计量装置的应变测量需求。(The invention relates to thin film strain gauges for elastic body strain measurement and a preparation method thereof, wherein an insulation isolation layer, a strain sensitive layer and a protective layer in the thin film strain gauge are all prepared on an elastic body, wherein the insulation isolation layer is prepared on the surface of the elastic body and is used for electrical insulation between the whole thin film strain gauge and elastic alloy, the strain sensitive layer is prepared above the insulation isolation layer and is used for strain measurement, the protective layer is prepared on the strain sensitive layer and is provided with a lead electrode exposed out of the strain sensitive layer and is used for protecting the strain sensitive layer from the influence of the external environment and avoiding the phenomena of aging, corrosion and the like of the strain sensitive layer.)

The thin film strain gauge for measuring the strain of the elastomer comprises an elastomer, an insulating isolation layer, a strain sensitive layer and a protective layer, and is characterized in that the insulating isolation layer, the strain sensitive layer and the protective layer are all prepared on the elastomer 1, wherein the insulating isolation layer is prepared on the surface of the elastomer and is used for electrically insulating the whole thin film strain gauge from an elastic alloy, the strain sensitive layer is prepared above the insulating isolation layer and is used for measuring the strain, and the protective layer is prepared above the strain sensitive layer and is provided with a lead electrode exposed out of the strain sensitive layer and is used for protecting the strain sensitive layer from the influence of the external environment and avoiding the phenomena of aging, corrosion and the like of the strain sensitive layer.

2. The thin film strain gauge for elastomeric strain measurement of claim 1, wherein: the strain sensitive layer comprises an electrode, a transition grid, a sensitive grid and a transverse grid, and the electrode is used for leading out an electric signal of the strain sensitive layer with the resistance value changing; the electrode is connected with a sensitive grid through a transition grid, the sensitive grid is used for sensing resistance change caused by strain, and the sensitive grid is formed by a plurality of long and thin strip-shaped structures and is used for reflecting the resistance change caused by strain in the longitudinal direction to the maximum extent; the sensing grids are connected through the transverse grids, the transverse grids play a role in connecting the sensing grids, so that the overall size of the strain sensing layer is reduced, and the transverse grids are in short-circuit structures and can reduce the transverse effect of the film strain gauge.

3. The thin film strain gauge for elastomeric strain measurement of claim 2, wherein: when the elastic body is deformed by external physical quantity, the length of the sensitive grid in the strain sensitive layer is extended or shortened, and the resistance of the strain sensitive layer is changed according to the resistance strain effect, so that the resistance under the action of unknown physical quantity is output, and a strain value under the action of corresponding physical quantity is obtained according to the relationship between the resistance and the strain.

4. The thin film strain gauge for elastomeric strain measurement of claim 1, wherein: and signal wires are welded on the electrodes of the strain sensitive layer, the electric signals generated by the film strain gauge are transmitted to the measuring circuit through the signal wires, and the measuring circuit performs temperature compensation and amplification treatment, so that adverse effects of the environment on a strain measuring result are avoided.

A method of manufacturing a thin film strain gauge for elastomeric strain measurement as claimed in any of claims 1-4 to in , comprising the steps of:

, polishing the surface of the elastomer substrate;

secondly, covering layers of polymer on the elastomer substrate polished in the step by adopting a spin coating method to form an insulating isolation layer, wherein the polymer can be electrophoretic paint;

sputtering layers of alloy films on the upper surface of the insulating isolation layer formed in the second step to obtain a strain sensitive layer, wherein the alloy films select Cr/NiCr or Cr/CuNi, the thickness of the Cr is 10-30 nm as the bonding layer, and the thickness of the CuNi or NiCr is 200-500 nm;

and fourthly, covering protective layers on the strain sensitive layer formed in the third step by using a spin coating method, and exposing the lead electrode by using an etching method to obtain the film strain gauge.

Technical Field

The invention relates to thin film strain gauges, in particular to thin film strain gauges which are directly prepared on the surface of an elastic body and used for measuring micro strain of the elastic body.

Background

The strain measurement technology has extensive applications in many fields, is obtained by converting most physical quantities such as force, torque, speed, acceleration and the like into indirect measurement on strain, so that the strain sensor becomes the core of most measurement instruments on the market at present, and is simple in structure and principle, stable and reliable in performance and convenient to use.

The existing resistance-type strain sensor mainly uses a paste-type resistance strain gauge, and has the advantages of small additional mass, high precision, high response speed, capability of simultaneously performing dynamic and static measurement and the like.

In addition, , the thickness of the film strain gauge is in the micrometer or even nanometer level, the sensitivity, the measurement precision and the response speed of the film strain gauge are improved steps on the basis of the adhesive type resistance strain gauge, and the tiny structure enables the film strain gauge not to influence the mechanical characteristics of the test environment.

Through the research on the prior art, the research on the thin film strain gauge is found, and the research results of the electronics technology university are most representative in China, for example, the university of electronics technology thesis "research on TaN thin film strain gauge for turbine blade strain measurement", "research on NiCr thin film strain gauge for turbine blade strain measurement", and the like, and the liuhao et al "research on PdCr thin film resistance strain gauge and high temperature strain sensitivity thereof", and the like, and the researched thin film strain gauges are all used for the strain measurement of the turbine blade in the high temperature situation. The invention provides a film strain gauge for measuring an elastic body, which is mainly characterized in that the film strain gauge is prepared on an elastic body alloy, the elastic body prepared with the film strain gauge can be used as a strain measuring element of other measuring equipment, and the working principle, the structural form and the applicable object of the film strain gauge are different from those of the film strain gauge applied to a turbine blade.

Disclosure of Invention

The invention provides film strain gauges for elastomer strain measurement aiming at the strain measurement requirement of elastomer alloy, the film strain gauge based on the film processing technology can be applied to other metering devices, and the accurate strain value of the elastomer is provided for the device by analyzing the resistance value change of the film strain gauge on the elastomer, so as to obtain the physical quantity to be measured required by the metering device.

The technical scheme includes that the film strain gauges for elastomer strain measurement comprise elastomers, insulating isolation layers, strain sensitive layers and protective layers, wherein the insulating isolation layers, the strain sensitive layers and the protective layers are all prepared on the elastomers, the insulating isolation layers are prepared on the surfaces of the elastomers and are used for electrical insulation between the whole film strain gauges and elastic alloys, the strain sensitive layers are prepared above the insulating isolation layers and are used for strain measurement, and the protective layers are prepared on the strain sensitive layers and are provided with lead electrodes exposed out of the strain sensitive layers and used for protecting the strain sensitive layers from the influence of the external environment and avoiding the phenomena of aging, corrosion and the like of the strain sensitive layers.

, the strain sensitive layer comprises an electrode, a transition grid, a sensitive grid and a transverse grid, the electrode is used for leading out an electric signal of resistance value change of the strain sensitive layer, the electrode is connected with the sensitive grid through the transition grid, the sensitive grid is used for sensing the resistance change caused by strain, the sensitive grid is composed of a plurality of long and thin strip-shaped structures and used for reflecting the resistance change caused by strain in the longitudinal direction to the maximum extent, the long and thin strip-shaped structures of the sensitive grid are connected through the transverse grid, the transverse grid plays a role in connecting the sensitive grids so as to reduce the overall size of the strain sensitive layer, and the transverse grid is in a short circuit structure and can reduce the transverse effect of the film strain gauge.

And , when the elastic body is deformed by the external physical quantity, the length of the sensitive grid in the strain sensitive layer is extended or shortened, and the resistance of the strain sensitive layer is changed according to the resistance strain effect, so that the resistance under the action of unknown physical quantity is output, and the strain value under the action of corresponding physical quantity is obtained according to the relationship between the resistance and the strain.

And , welding signal wires on the electrodes of the strain sensitive layer, transmitting the electric signals generated by the thin film strain gauge to a measuring circuit through the signal wires, and performing temperature compensation and amplification processing by the measuring circuit to avoid adverse effects of the environment on the strain measurement result.

A method for preparing a film strain gauge for elastomer strain measurement, comprising the following steps:

, polishing the surface of the elastomer substrate;

secondly, covering layers of polymer on the elastomer substrate polished in the step by adopting a spin coating method to form an insulating isolation layer, wherein the polymer can be electrophoretic paint;

sputtering layers of alloy films on the upper surface of the insulating isolation layer formed in the second step to obtain a strain sensitive layer, wherein the alloy films select Cr/NiCr or Cr/CuNi, the thickness of the Cr is 10-30 nm as the bonding layer, and the thickness of the CuNi or NiCr is 200-500 nm;

and fourthly, covering protective layers on the strain sensitive layer formed in the third step by using a spin coating method, and exposing the lead electrode by using an etching method to obtain the film strain gauge.

The invention has the beneficial effects that:

the film strain gauge for measuring the elastic body strain is different from the traditional sticking type resistance strain gauge, does not need to introduce a sticking agent, thereby avoiding the problem of large hysteresis and creep deformation, has the advantages of simple structure, high precision and high response speed, and the prepared elastic body of the film strain gauge can better meet the strain measurement requirements of other metering devices.

Drawings

FIG. 1 is a cross-sectional view of a thin film strain gauge on elastomer;

FIG. 2 is a top view of a thin film strain gage on elastomer structure;

fig. 3 is a schematic diagram of a thin film strain gauge.

Detailed Description

The invention is further illustrated in with reference to the following figures and examples.

As shown in fig. 1 and 2, the thin film strain gauge for measuring the strain of an elastic body of the present invention includes an elastic body 1, an insulating isolation layer 2, a strain sensitive layer 3 and a protection layer 4. The insulation isolation layer 2, the strain sensitive layer 3 and the protective layer 4 are all prepared on the elastic body, wherein the insulation isolation layer 2 is prepared on the surface of the elastic body 1 and is used for electrical insulation between the whole thin film strain gauge and the elastic alloy; the strain sensitive layer 3 is prepared above the insulating isolation layer 2 and used for measuring strain; the protective layer 4 is prepared on the strain sensitive layer 3, and a lead electrode of the strain sensitive layer 3 needs to be exposed, so as to protect the strain sensitive layer 3 from being influenced by the external environment and avoid the phenomena of aging, corrosion and the like of the strain sensitive layer 3.

As shown in fig. 3, the strain sensitive layer 3 includes an electrode 5, a transition gate 6, a sensitive gate 7 and a lateral gate 8. The electrode 5 is used for leading out an electric signal of the change of the resistance value of the strain sensitive layer; the transition gate 6 structurally plays a role in reducing local stress; the sensitive grid 7 is a main structure for sensing resistance change caused by strain, and the structure of the sensitive grid is designed to be a long and thin strip shape, so that the resistance change caused by strain in the longitudinal direction can be reflected to the maximum extent; the transverse grating 8 serves to connect the individual sensitive gratings so as to reduce the overall size of the strain sensitive layer 3, while the transverse grating 8 should be designed as a short-circuited structure in order to reduce the lateral effects of the thin film strain gauge.

And signal wires are welded on the electrodes of the strain sensitive layer 3, an electric signal generated by the film strain gauge is transmitted to the measuring circuit through the signal wires, and the measuring circuit performs temperature compensation and amplification treatment, so that adverse effects of the environment on a strain measuring result are avoided.

The thin film strain gauges for elastomer strain measurement can be prepared by the following preparation method, which comprises the following steps:

, polishing the surface of the elastomer 1 substrate;

secondly, covering layers of polymer on the elastomer substrate polished in the step by adopting a spin coating method to form an insulating isolation layer 2, wherein the polymer can be electrophoretic paint;

sputtering layers of alloy films on the upper surface of the insulating isolation layer 2 formed in the second step to obtain a strain sensitive layer 3, wherein the alloy films can be selected from Cr/NiCr, Cr/CuNi and other combinations, the thickness of the Cr as a bonding layer is 10-30 nm, and the thicknesses of the CuNi and the NiCr are flexibly selected between 200 and 500 nm;

and fourthly, covering protective layers 4 on the strain sensitive layer 3 formed in the third step by using a spin coating method, and exposing the lead electrodes by using an etching method to obtain the film strain gauge.

When the elastic body deforms under the action of unknown physical quantity, the resistance of the thin film strain gauge prepared on the surface of the elastic body is changed. Specifically, when an elastic body is deformed due to an external physical quantity, the structure of the strain sensitive layer 3 of the film strain gauge changes, the length of the sensitive grid 7 in the strain sensitive layer 3 is elongated or shortened according to the direction of the external action, and the resistance is calculated according to the formula (1):

wherein R is the resistance of the strain sensitive layer 3; ρ is the resistivity of the material used for the strain sensitive layer 3; l is the total length of the structure of the strain sensitive layer 3, and the length of the sensitive grid can be multiplied by the number of the sensitive grids to approximate; and S is the thickness of the prepared strain sensitive layer. The change of the length of the sensitive gate can cause the resistance of the strain sensitive layer 3 to change, so that the resistance under the action of unknown physical quantity is output, and the strain value under the action of corresponding physical quantity can be obtained by analyzing the relationship between the resistance and the strain.