Piezoresistive sensor

Abstract

The utility model relates to the technical field of pressure detection, in particular to a piezoresistive sensor. According to the piezoresistive sensor provided by the utility model, the protective sheet is arranged on the pressed surface of the sensor, and an object presses the sensor through the protective sheet, so that a crease caused by the fact that the object only presses the local part of the sensor is avoided, and the measurement accuracy of the sensor is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of pressure detection, in particular to a piezoresistive sensor. Background Art

[0002] A piezoresistive sensor is a sensor that measures pressure, force, or other physical quantities that can be converted into force changes (such as liquid level, acceleration, weight, strain, flow, and vacuum) based on the piezoresistive effect of semiconductor materials. Most of them consist of three parts: a first electrode, a second electrode, and a pressure-sensitive material sandwiched between the first electrode and the second electrode. When the sensor is pressurized, the resistivity of the pressure-sensitive material changes (in most cases, its resistivity decreases as pressure increases, i.e., it has a negative piezoresistive property); by detecting the resistance value between the first electrode and the second electrode, the pressure value at the current position can be obtained.

[0003] Current piezoresistive sensors, especially flexible piezoresistive sensors, are prone to permanent deformation such as creases when subjected to pressure in actual use if an irregular object only presses a part of the sensor. Permanent deformation will cause internal inherent stress in the piezoresistive sensor, resulting in a large deviation in the pressure measurement accuracy of the sensor, and may even cause damage to the sensor. Utility Model Content

[0004] The embodiment of the utility model provides a piezoresistive sensor to solve the problem in the prior art that the measurement accuracy may deviate or even the sensor may be damaged due to the permanent deformation of a part of the piezoresistive sensor caused by pressure.

[0005] In a first aspect, the utility model provides a piezoresistive sensor, comprising a sensor body and a protective sheet, the sensor body comprising: a top structure, a pressure-sensitive layer and a bottom structure, the pressure-sensitive layer being arranged between the top structure and the bottom structure, the protective sheet being arranged on the pressure-bearing surface of the top structure and / or the bottom structure.

[0006] In one embodiment, the area of ​​the protection sheet is larger than the area of ​​the pressure-sensitive layer, and the position of the protection sheet corresponds to the position of the pressure-sensitive layer in the upper and lower directions.

[0007] In one embodiment, the projection area of ​​the protection sheet covers the projection area of ​​the pressure-sensitive layer.

[0008] In one embodiment, the protection sheet is in a circular shape.

[0009] In one embodiment, the contact edge between the protection sheet and the sensor body is configured as a rounded corner or a chamfered corner.

[0010] In one embodiment, the protection sheet is adhesively connected to the pressure-bearing surface of the sensor body.

[0011] In one embodiment, the top structure includes: a top film, a top electrode and a top lead, the top electrode and the pressure-sensitive layer are stacked, the top lead is electrically connected to the top electrode, the top electrode and the top lead are laminated and fixed on the top film, or the top electrode and the top lead are printed on the top film.

[0012] In one embodiment, the underlying structure includes: an underlying film, an underlying electrode and an underlying lead, the underlying electrode and the pressure-sensitive layer are stacked, the underlying lead is electrically connected to the underlying electrode, the underlying electrode and the underlying lead are laminated and fixed on the underlying film, or the underlying electrode and the underlying lead are printed on the underlying film.

[0013] In one embodiment, the center position of the top electrode, the center position of the pressure-sensitive layer, and the center position of the bottom electrode overlap with each other along the thickness direction of the protection sheet.

[0014] In one embodiment, the material of the protection sheet includes: stainless steel, plastic or ceramic.

[0015] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0016] The piezoresistive sensor of the utility model has a protective sheet arranged on the pressure-bearing surface of the sensor. When an object presses the sensor through the protective sheet, creases caused by the object pressing only a part of the sensor are avoided, thereby ensuring the measurement accuracy of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments of the utility model will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 It is a three-dimensional structural schematic diagram of a piezoresistive sensor provided in one embodiment of the utility model;

[0019] Figure 2 This is an exploded schematic diagram of a piezoresistive sensor provided in one embodiment of the utility model;

[0020] Among them, 1. protective sheet, 2. top structure, 3. bottom structure, 4. pressure-sensitive layer, 11. rounded corners, 21. top film, 22. top electrode, 23. top lead, 31. bottom film, 32. bottom electrode, 33. bottom lead. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and beneficial effects solved by the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0022] In the description of the present invention, it should be understood that the terms "longitudinal", "radial", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the 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 a limitation on the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" 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 or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] In order to thoroughly understand the present invention, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by the present invention. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0025] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure belongs. It will be further understood that the terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein.

[0026] like Figure 1As shown, a three-dimensional structural schematic diagram of a piezoresistive sensor is provided, such as Figure 2 As shown, an explosion diagram of a piezoresistive sensor is provided.

[0027] In one embodiment, if Figure 1 and Figure 2 As shown, the piezoresistive sensor includes a sensor body and a protective sheet 1. The sensor body includes: a top structure 2, a pressure-sensitive layer 4 and a bottom structure 3. The pressure-sensitive layer 4 is arranged between the top structure 2 and the bottom structure 3, and the protective sheet 1 is arranged on the pressure-bearing surface of the top structure 2 and / or the bottom structure 3.

[0028] It is understandable that the protective sheet 1 should be a protective sheet 1 formed of a material with a certain hardness. The shape, size and position of the protective sheet 1 can be set according to the actual application situation. The shape of the protective sheet 1 can be square, and the shape of the protective sheet 1 can be circular. Preferably, the upper surface of the protective sheet 1 and the lower surface of the protective sheet 1 should be parallel to each other. The size of the protective sheet 1 can be smaller than the size of the pressure-sensitive layer 4, the size of the protective sheet 1 can also be the same as the size of the pressure-sensitive layer 4, and the size of the protective sheet 1 can also be larger than the size of the pressure-sensitive layer 4. It is understandable that the protective sheet 1 should cover a partial area of ​​the pressure-sensitive layer 4.

[0029] The pressure-bearing surface of the top structure 2 is a preset area on the upper surface of the top structure 2 , and the pressure-bearing surface of the bottom structure 3 is a preset area on the lower surface of the bottom structure 3 .

[0030] The number of protective sheets 1 can be set according to specific application conditions. The protective sheets 1 can be respectively set on the upper and lower surfaces of the sensor body, or only on one side of the sensor body.

[0031] The piezoresistive sensor of this embodiment, the piezoresistive sensor of the utility model, is provided with a protective sheet 1 on the pressure-bearing surface of the sensor. The object presses the sensor through the protective sheet 1, thereby avoiding creases caused by the object pressing only part of the sensor, thereby ensuring the measurement accuracy of the sensor.

[0032] In one embodiment, if Figure 2 As shown, based on the above embodiment, the area of ​​the protection sheet 1 is larger than the area of ​​the pressure-sensitive layer 4 , and the position of the protection sheet 1 corresponds to the position of the pressure-sensitive layer 4 in the upper and lower directions.

[0033] Specifically, the protection sheet 1 may correspond to only part of the pressure-sensitive layer 4 above and below, or the protection sheet 1 may correspond to the entire pressure-sensitive layer 4 , covering the corresponding position of the entire pressure-sensitive layer 4 on the surface of the sensor body.

[0034] In the piezoresistive sensor of this embodiment, the position of the protective sheet 1 corresponds to the position of the pressure-sensitive layer 4 in the vertical direction, thereby ensuring that the protective sheet 1 can protect the pressure-sensitive layer 4 .

[0035] In one embodiment, if Figure 2 As shown, based on the above embodiment, the projection area of ​​the protection sheet 1 covers the projection area of ​​the pressure-sensitive layer 4 .

[0036] Specifically, the protection sheet 1 corresponds to the entire pressure-sensitive layer 4 and covers the corresponding position of the entire pressure-sensitive layer 4 on the surface of the sensor body.

[0037] The piezoresistive sensor of this embodiment has the protective sheet 1 covering the corresponding position of the entire pressure-sensitive layer 4 on the surface of the sensor body. An object passing through the protective sheet 1 can only press the entire sensor, which can completely avoid creases caused by the object only pressing a part of the sensor.

[0038] In one embodiment, if Figure 1 and Figure 2 As shown, based on the above embodiment, the shape of the protection sheet 1 is a circular structure.

[0039] In the piezoresistive sensor of this embodiment, the shape of the protective sheet 1 is set to be circular, so that the shape of the protective sheet 1 is consistent with the shape of the pressure-sensitive layer 4 and the shape of the electrode, making it easier for the protective sheet 1 to cover the corresponding position of the entire pressure-sensitive layer 4 on the surface of the sensor body.

[0040] In one embodiment, if Figure 1 and Figure 2 As shown, based on the above embodiment, the contact edge between the protection sheet 1 and the sensor body is set to be a rounded corner 11 or a chamfer.

[0041] The size of the fillet 11 or the size of the chamfer can be set according to the actual application. Figure 1 As shown, the contact edge between the protection sheet 1 and the sensor body is configured as a rounded corner 11 .

[0042] In the piezoresistive sensor of this embodiment, the contact edge between the protection sheet 1 and the sensor body is configured as a rounded corner 11 or a chamfer to prevent the protection sheet 1 from cutting the sensor body in extreme cases.

[0043] In one embodiment, based on the above embodiment, the protection sheet 1 is adhesively connected to the pressure-bearing surface of the sensor body.

[0044] Specifically, the protection sheet 1 is adhered to the pressure-bearing surface of the sensor body by gluing.

[0045] In the piezoresistive sensor of this embodiment, the protection sheet 1 is adhesively connected to the sensor body to ensure that the protection sheet 1 can be well fixed and that the surface of the protection sheet 1 is parallel to the pressure surface of the sensor body, thereby avoiding deviation in pressure measurement due to sensor tilt.

[0046] In one embodiment, if Figure 2As shown, on the basis of the above embodiments, the top structure 2 includes: a top film 21, a top electrode 22 and a top lead 23, the top electrode 22 is stacked with the pressure-sensitive layer 4, the top lead 23 is electrically connected to the top electrode 22, the top electrode 22 and the top lead 23 are laminated and fixed on the top film 21, or the top electrode 22 and the top lead 23 are printed on the top film 21.

[0047] It is understandable that the upper surface of the pressure-sensitive layer 4 should be in contact with the electrode on the top structure 2 so that the pressure-sensitive layer 4 and the electrode on the top structure 2 form a conductive connection. The shape of the top lead 23 can be set according to the actual application situation. The conductive material can be pressed onto the top film 21 using a lamination process, and then the shape of the top electrode 22 and the top lead 23 can be prepared using an etching process. The top electrode 22 and the top lead 23 can also be printed on the top film 21 using a conductive paste printing process.

[0048] The piezoresistive sensor of this embodiment has a top-level electrode 22 connected to the piezoresistive layer 4. The top-level electrode 22 can obtain an electrical signal of a resistance change of the piezoresistive layer 4 due to force. The top-level lead 23 is used to introduce current and simultaneously export electrical signals, thereby ensuring the reliability of the piezoresistive sensor.

[0049] In one embodiment, if Figure 2 As shown, on the basis of the above embodiments, the bottom structure 3 includes: a bottom film 31, a bottom electrode 32 and a bottom lead 33, the bottom electrode 32 is stacked with the pressure-sensitive layer 4, the bottom lead 33 is electrically connected to the bottom electrode 32, the bottom electrode 32 and the bottom lead 33 are laminated and fixed on the bottom film 31, or the bottom electrode 32 and the bottom lead 33 are printed on the bottom film 31.

[0050] It is understandable that the lower surface of the pressure-sensitive layer 4 should be in contact with the electrode on the bottom structure 3, so that the pressure-sensitive layer 4 and the electrode on the bottom structure 3 form a conductive connection. The shape of the bottom lead 33 can be set according to the actual application. The conductive material can be pressed onto the bottom film 31 by a lamination process, and then the shape of the bottom electrode 32 and the bottom lead 33 can be prepared by an etching process; or the bottom electrode 32 and the bottom lead 33 can be printed on the bottom film 31 by a conductive paste printing process.

[0051] In the piezoresistive sensor of this embodiment, the top electrode 22 and the bottom electrode 32 are connected to the pressure-sensitive layer 4. The two electrodes can obtain the electrical signal of the resistance change of the pressure-sensitive layer 4 due to the force. The top lead 23 and the bottom lead 33 are used to introduce the current and export the electrical signal at the same time, so as to further ensure the reliability of the piezoresistive sensor.

[0052] In one embodiment, if Figure 2As shown, based on the above embodiment, the center position of the top electrode 22 , the center position of the pressure-sensitive layer 4 and the center position of the bottom electrode 32 overlap with each other along the thickness direction of the protection sheet 1 .

[0053] The piezoresistive sensor of this embodiment makes the center position of the top electrode 22, the center position of the pressure-sensitive layer 4 and the center position of the bottom electrode 32 overlap each other along the thickness direction of the protective sheet 1. This layout can maximize the contact area between the electrode and the pressure-sensitive layer 4, thereby optimizing the transmission efficiency of the electrical signal. When pressure acts on the pressure-sensitive layer 4 to cause resistance changes, this direct and large-area contact can ensure that the change is quickly and accurately transmitted to the electrode, and then converted into an electrical signal output.

[0054] In one embodiment, based on the above embodiment, the material of the protection sheet 1 includes: stainless steel, plastic or ceramic.

[0055] The piezoresistive sensor of this embodiment uses stainless steel, plastic or ceramic as the material of the protective sheet 1, so that the protective sheet 1 has a certain hardness to prevent objects from passing through the protective sheet 1 to form creases on the pressure-sensitive layer 4, ensuring that the protective sheet 1 can protect the pressure-sensitive layer 4.

[0056] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A piezoresistive sensor, characterized in that: The sensor body comprises a sensor body and a protective sheet, wherein the sensor body comprises a top structure, a pressure-sensitive layer and a bottom structure, wherein the pressure-sensitive layer is arranged between the top structure and the bottom structure, and the protective sheet is arranged on the pressure-bearing surface of the top structure and / or the bottom structure.

2. The piezoresistive sensor according to claim 1, characterized in that: The area of ​​the protection sheet is larger than that of the pressure-sensitive layer, and the position of the protection sheet corresponds to that of the pressure-sensitive layer in a vertical direction.

3. The piezoresistive sensor according to claim 2, characterized in that: The projection area of ​​the protection sheet covers the projection area of ​​the pressure-sensitive layer.

4. The piezoresistive sensor according to claim 3, characterized in that: The protection sheet is in a circular shape.

5. The piezoresistive sensor according to claim 4, characterized in that: The contact edge between the protection sheet and the sensor body is configured as a rounded corner or a chamfered corner.

6. The piezoresistive sensor according to claim 1, characterized in that: The protection sheet is adhesively connected to the pressure-bearing surface of the sensor body.

7. The piezoresistive sensor according to claim 1, wherein: The top structure includes: a top film, a top electrode and a top lead. The top electrode is stacked with the pressure-sensitive layer, the top lead is electrically connected to the top electrode, and the top electrode and the top lead are laminated and fixed on the top film, or the top electrode and the top lead are printed on the top film.

8. The piezoresistive sensor according to claim 7, characterized in that: The bottom structure includes: a bottom film, a bottom electrode and a bottom lead. The bottom electrode is stacked with the pressure-sensitive layer, the bottom lead is electrically connected to the bottom electrode, and the bottom electrode and the bottom lead are laminated and fixed on the bottom film, or the bottom electrode and the bottom lead are printed on the bottom film.

9. The piezoresistive sensor according to claim 7, characterized in that: The center position of the top electrode, the center position of the pressure-sensitive layer and the center position of the bottom electrode overlap with each other along the thickness direction of the protection sheet.

10. The piezoresistive sensor according to claim 1, wherein: The material of the protection sheet includes: stainless steel, plastic or ceramic.

Images