Strain gauge capable of improving sensitivity of key sensor

Abstract

The invention discloses a strain gauge for improving the sensitivity of a key sensor. The strain gauge comprises four sensitive grids and four bonding pads, the four sensitive grids are all located on one side of the fixed end, the four bonding pads are all located on one side of the loading end, and the four sensitive grids and the four bonding pads form a completely-closed full-bridge strain gauge. According to an existing strain gauge design technology, the four sensitive grids are arranged close to the fixed end according to borne main strain and Poisson strain, as the deformation amount of the fixed end is maximum, the two grids are both under the maximum stress strain load, the output sensitivity, the stability and the reliability of the sensor are improved, the sensitivity is improved to 3.8-5.2, and the stability and the reliability of the sensor are improved. A resistance strain gauge with higher sensitivity is provided for customers, the application and popularization of the micro strain gauge in the microelectronic industry are accelerated, and the micro strain gauge serves the society more widely.

Description

Technical Field

[0001] The invention belongs to the field of high-precision sensors and relates to a strain gauge for improving the sensitivity of a key sensor. Background Art

[0002] With the rapid development and continuous progress of modern science and technology, electronic products are developing towards miniaturization, and the corresponding accessories must also be smaller, so solid-state buttons have become a trend in the development of new technology. Since solid-state buttons have higher reliability, better feel and output stability, more and more devices such as mobile phones, watches, and micro PCs have begun to use solid-state buttons instead of physical buttons as the signal input end of the device. Taking advantage of the characteristics of high stability, good linearity, and high repeatability of strain sensors, strain sensors are made into solid-state buttons, which will give solid-state buttons a better pressing feel and grading experience; since the solid-state button has a small pressing deformation range, this requires the strain gauge sensor to have a great output sensitivity. Due to the spatial position and size restrictions of electronic products, the elastic deformation structure of solid-state buttons is small in size, generally in a cantilever beam structure, with one end fixed and the other end applying pressing force (loading). The shape and position of the fixed end and the loading end are slightly different according to the spatial structure of the electronic product. Taking a solid-state button mobile phone shrapnel with a cantilever beam structure as an example, the strain gauge pad is in the middle, and the sensitive grids at both ends bear tension and pressure respectively. The sensitivity of the resistive strain type button sensor is relatively small, about 2.0~2.6mV / V, and the actual pressing sensitivity is only 20%~50%. It has high requirements for the back-end signal processing circuit, the pressing button grading experience is poor, and the pad is led out from the middle, affecting the pull-out force, sensor creep back to zero and other performance. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a strain gauge for improving the sensitivity of a key sensor, thereby improving the sensitivity of the key sensor.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: A strain gauge for improving the sensitivity of a key sensor, comprising four sensitive grids and four pads; The four sensitive grids are all located on one side of the fixed end, the four pads are all located on one side of the loading end, and the four sensitive grids and the four pads form a completely closed full-bridge strain gauge.

[0005] Preferably, the resistance value of each sensitive grid is equal.

[0006] Preferably, the four sensitive grids include two transverse grids and two longitudinal grids, the two transverse grids are parallel to the axis of the principal stress of the force deformation, and the two longitudinal grids are perpendicular to the axis of the principal stress of the force deformation.

[0007] Furthermore, the two transverse grids are located on the upper and lower sides of the axis of the principal stress of the force deformation, and the two longitudinal grids are located on the upper and lower sides of the axis of the principal stress of the force deformation.

[0008] Furthermore, two transverse grids are close to the fixed end side, and two longitudinal grids are arranged next to the transverse grids, close to the loading end side.

[0009] Furthermore, the two longitudinal grids are arranged at opposite bridge positions of the Wheatstone bridge, and the two transverse grids are arranged at another opposite bridge position of the Wheatstone bridge.

[0010] Further, the four sensitive gates include a first transverse gate, a first longitudinal gate, a second transverse gate and a second longitudinal gate, and the four pads include a first pad, a second pad, a third pad and a fourth pad; the first pad, the second longitudinal gate and the second pad form a Wheatstone bridge arm; the second pad, the second transverse gate and the third pad form a Wheatstone bridge arm; the third pad, the first longitudinal gate and the fourth pad form a Wheatstone bridge arm; the fourth pad, the first transverse gate and the first pad form a Wheatstone bridge arm.

[0011] Furthermore, the first pad is the positive power supply of the bridge circuit, the second pad is the negative output of the bridge circuit, the third pad is the negative power supply of the bridge circuit, and the fourth pad is the positive output of the bridge circuit.

[0012] Preferably, the four sensitive grids include two oblique grids and two longitudinal grids, the two oblique grids are at an angle of 135° to the axial direction of the principal stress of the force deformation, and the two longitudinal grids are perpendicular to the axial direction of the principal stress of the force deformation.

[0013] Preferably, the four sensitive grids include two oblique grids and two longitudinal grids, the two oblique grids are at an angle of 45° to the axial direction of the principal stress of the force deformation, and the two longitudinal grids are perpendicular to the axial direction of the principal stress of the force deformation.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention is based on the existing strain gauge design technology, and according to the principal strain and Poisson strain, four sensitive grids are arranged near the fixed end. Since the deformation of the fixed end is the largest, both grids are under the maximum stress-strain load, which improves the output sensitivity, stability and reliability of the sensor. The sensitivity is increased to 3.8-5.2, providing customers with a resistance strain gauge with greater sensitivity, accelerating the application and promotion of micro strain gauges in the microelectronics industry, and serving the society more widely. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a strain gauge for improving the sensitivity of a key sensor of the present invention; Figure 2 The figure is a schematic diagram of a Wheatstone bridge circuit of a strain gauge for improving the sensitivity of a key sensor according to the present invention.

[0016] Among them: 1-first transverse grid; 2-first longitudinal grid; 3-second transverse grid; 4-second longitudinal grid; 5-first solder pad; 6-second solder pad; 7-third solder pad; 8-fourth solder pad. DETAILED DESCRIPTION

[0017] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0018] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, 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 limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs. The terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. The term "and / or" used in this article includes any and all combinations of one or more related listed items. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0020] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0021] like Figure 1 As shown, a strain gauge for improving the sensitivity of a key sensor according to the present invention is shown, which is a full-bridge strain gauge composed of four sensitive grids and four pads.

[0022] The four sensitive grids include a first transverse grid 1, a first longitudinal grid 2, a second transverse grid 3 and a second longitudinal grid 4. The four pads include a first pad 5, a second pad 6, a third pad 7 and a fourth pad 8. The four sensitive grids and the four pads form a completely closed full-bridge strain gauge. The four sensitive grids are all located on the fixed end side, and the four pads are all located on the loading end side.

[0023] In the present embodiment, the four sensitive grids of the strain gauge for improving the sensitivity of the key sensor, the first transverse grid 1, the first longitudinal grid 2, the second transverse grid 3 and the second longitudinal grid 4, have the same resistance value among each of the sensitive grids.

[0024] In the strain gauge for improving the sensitivity of a key sensor described in this embodiment, the first transverse grid 1 and the second transverse grid 3 are arranged near the fixed end, the first transverse grid 1 and the second transverse grid 3 are on the same vertical line and arranged up and down, and the two transverse grids are arranged at the opposite bridge position of the Wheatstone bridge. When the sensor is subjected to a pressure load, the first transverse grid 1 and the second transverse grid 3 are subjected to pressure, generating negative strain.

[0025] In the strain gauge for improving the sensitivity of the key sensor described in this embodiment, the first longitudinal grid 2 and the second longitudinal grid 4 are arranged at adjacent positions next to the two transverse grids, the first longitudinal grid 2 and the second longitudinal grid 4 are on the same vertical line and arranged up and down, and the two sensitive grids are arranged at the opposite bridge positions of the Wheatstone bridge. When the sensor is subjected to a pressure load, the first longitudinal grid 2 and the second longitudinal grid 4 are subjected to tension, generating positive strain.

[0026] The strain gauge for improving the sensitivity of the key sensor described in this embodiment has four sensitive grids. The four sensitive grids of the strain gauge are close to the fixed end of the solid key. Two transverse grids sensing the principal stress are arranged on the upper and lower sides along the principal stress axis of the force deformation, and are parallel to the principal stress axis. The other two longitudinal grids are arranged close to the transverse grids, and the longitudinal grid axes are perpendicular to the principal stress axis. The two longitudinal grids are arranged at the opposite bridge position of the Wheatstone bridge, and the two transverse grids are arranged at the other opposite bridge position of the Wheatstone bridge.

[0027] In the strain gauge for improving the sensitivity of the key sensor described in this embodiment, two transverse grids bear principal stress (principal strain), the two transverse grids are parallel to the principal stress axis, the two transverse grids are arranged on the upper and lower sides of the same axis, and the two transverse grids are arranged adjacent to each other up and down. When the key sensor is loaded, the two transverse grids bear the same magnitude of principal stress (principal strain).

[0028] In the strain gauge for improving the sensitivity of the key sensor described in this embodiment, two sensitive grids (longitudinal grids) perpendicular to the principal stress axis are subjected to transverse stress (Poisson strain), and the two longitudinal grids are arranged on the upper and lower sides of the same axis, and the two longitudinal grids are arranged adjacent to each other up and down. When the key sensor is loaded, the two longitudinal grids are subjected to the same magnitude of transverse stress (Poisson strain) in the opposite direction to the principal stress.

[0029] The strain gauge for improving the sensitivity of a key sensor described in this embodiment reasonably connects four sensitive gates to form a full bridge according to the principal strain and Poisson strain it bears, and sets four pads near the loading end, two of which are connected to the excitation and the other two are output signals.

[0030] Compared with the prior art, the strain gauge for improving the sensitivity of the button sensor described in this embodiment sets both the transverse grid and the longitudinal grid close to the fixed end. Since the deformation of the fixed end is the largest, both grids are under the maximum stress-strain load, thereby improving the output sensitivity, stability and reliability of the sensor.

[0031] A strain gauge for improving the sensitivity of a key sensor described in this embodiment is a closed full-bridge circuit, having four sensitive grids and four pads, wherein the transverse grid is closest to the fixed end, and the longitudinal grid is next to the transverse grid. The pads are respectively the first pad 5, the second pad 6, the third pad 7 and the fourth pad 8, and the four pads are arranged in two rows parallel to the principal stress axis.

[0032] Figure 2 Schematic diagram of a Wheatstone bridge circuit of a strain gauge for improving the sensitivity of a key sensor according to the present embodiment. In the present embodiment, the first pad 5, the second longitudinal grid 4 and the second pad 6 form a Wheatstone bridge arm.

[0033] In this embodiment, the second pad 6, the second lateral gate 3 and the third pad 7 also form a Wheatstone bridge arm.

[0034] In this embodiment, the third pad 7, the first longitudinal grid 2 and the fourth pad 8 also form a Wheatstone bridge arm.

[0035] Furthermore, in this embodiment, the fourth pad 8, the first transverse gate 1 and the first pad 5 also form a Wheatstone bridge arm.

[0036] In this embodiment, the first pad 5 is the positive power supply of the bridge circuit, the second pad 6 is the negative output of the bridge circuit, the third pad 7 is the negative power supply of the bridge circuit, and the fourth pad 8 is the positive output of the bridge circuit.

[0037] The strain gauge for improving the sensitivity of the key sensor described in this embodiment is characterized by: (1) The strain gauge is composed of four sensitive grids and four pads to form a full-bridge strain gauge. (2) The four sensitive grids of the strain gauge are all close to the fixed end of the solid-state key, and two transverse grids that sense the principal stress are set along the axis of the principal stress of the force deformation and are parallel to the axis of the principal stress. The other two longitudinal grids are set close to the transverse grids, and the longitudinal grid axis is perpendicular to the axis of the principal stress. (3) The two transverse grids (axial) bear the principal stress (principal strain, compressive strain), and the two longitudinal grids perpendicular to the axis of the principal stress bear the transverse stress (Poisson strain, tensile strain). (4) According to the principal strain and Poisson strain borne, the four sensitive grids are reasonably connected to form a full bridge, and four pads are set near the loading end, two of which are connected to the excitation and the other two are output signals.

[0038] The strain gauge for improving the sensitivity of a key sensor described in this embodiment improves the sensitivity of the key sensor, and the sensitivity is improved to 3.8-5.2.

[0039] In summary, the present invention relates to a strain gauge for improving the sensitivity of a button sensor, which is creative. The graphic structure (grid bar angle) of the sensitive grid is not limited to the transverse grid and the longitudinal grid shown in the embodiment, and can be expanded to strain gauges with other complex structures such as more sensitive grid types (45-degree grid or 135-degree grid combined with longitudinal grid).

[0040] The present invention relates to a strain gauge for improving the sensitivity of a key sensor. Based on the existing strain gauge design technology and combined with the new strain gauge graphic design structure developed by the present invention, a resistance strain gauge with greater sensitivity is provided to customers, which accelerates the application and promotion of micro strain gauges in the microelectronics industry and serves the society more widely.

[0041] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0042] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this patent should not be determined with reference to the above description, but rather with reference to the preceding claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a waiver of such subject matter, nor should it be considered that the applicant has not considered such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A strain gauge for improving the sensitivity of a key sensor, characterized in that: It includes four sensitive grids and four pads; The four sensitive grids are all located on one side of the fixed end, the four pads are all located on one side of the loading end, and the four sensitive grids and the four pads form a completely closed full-bridge strain gauge.

2. The strain gauge for improving the sensitivity of a key sensor according to claim 1, characterized in that: The resistance value of each sensitive grid is equal.

3. The strain gauge for improving the sensitivity of a key sensor according to claim 1, characterized in that: The four sensitive grids include two transverse grids and two longitudinal grids. The two transverse grids are parallel to the axial direction of the principal stress of the force deformation, and the two longitudinal grids are perpendicular to the axial direction of the principal stress of the force deformation.

4. The strain gauge for improving the sensitivity of a key sensor according to claim 3, characterized in that: The two transverse grids are located on the upper and lower sides of the axis of the principal stress of the force deformation, and the two longitudinal grids are located on the upper and lower sides of the axis of the principal stress of the force deformation.

5. The strain gauge for improving the sensitivity of a key sensor according to claim 4, characterized in that: The two transverse grids are close to the fixed end side, and the two longitudinal grids are arranged next to the transverse grids, close to the loading end side.

6. The strain gauge for improving the sensitivity of a key sensor according to claim 3, characterized in that: The two longitudinal grids are arranged at opposite bridge positions of the Wheatstone bridge, and the two transverse grids are arranged at the other opposite bridge positions of the Wheatstone bridge.

7. The strain gauge for improving the sensitivity of a key sensor according to claim 3, characterized in that: The four sensitive gates include a first transverse gate (1), a first longitudinal gate (2), a second transverse gate (3) and a second longitudinal gate (4); the four pads include a first pad (5), a second pad (6), a third pad (7) and a fourth pad (8); the first pad (5), the second longitudinal gate (4) and the second pad (6) form a Wheatstone bridge arm; the second pad (6), the second transverse gate (3) and the third pad (7) form a Wheatstone bridge arm; the third pad (7), the first longitudinal gate (2) and the fourth pad (8) form a Wheatstone bridge arm; the fourth pad (8), the first transverse gate (1) and the first pad (5) form a Wheatstone bridge arm.

8. The strain gauge for improving the sensitivity of a key sensor according to claim 7, characterized in that: The first pad (5) is the positive power supply of the bridge circuit, the second pad (6) is the negative output of the bridge circuit, the third pad (7) is the negative power supply of the bridge circuit, and the fourth pad (8) is the positive output of the bridge circuit.

9. The strain gauge for improving the sensitivity of a key sensor according to claim 1, characterized in that: The four sensitive grids include two oblique grids and two longitudinal grids. The angle between the two oblique grids and the axial direction of the principal stress of the force deformation is 135°, and the two longitudinal grids are perpendicular to the axial direction of the principal stress of the force deformation.

10. The strain gauge for improving the sensitivity of a key sensor according to claim 1, characterized in that: The four sensitive grids include two oblique grids and two longitudinal grids. The two oblique grids are at an angle of 45° to the axial direction of the principal stress of the force deformation, and the two longitudinal grids are perpendicular to the axial direction of the principal stress of the force deformation.

Images