Sensor unit and flexible pressure sensor

Abstract

According to the flexible pressure sensor and the sensor unit thereof, the low-cost MEMS pressure chip can be used for pressure load measurement, the structure is simple, the MEMS pressure chip is effectively protected, and the flexible pressure sensor and the sensor unit thereof are particularly suitable for pressure measurement of a robot. The sensor unit includes: a pressure sensitive element having a laterally extending elastic membrane; the pressure transmitting element is provided with a pressure transmitting part which is used for receiving and transmitting longitudinal pressure to the elastic membrane towards one side of the longitudinal near end; and the elastic recovery element is used for enabling the pressure transmission element to be separated from or only abut against the elastic film towards one side of the longitudinal far end when the longitudinal pressure is lower than the preset pressure. The flexible pressure sensor comprises: a plurality of sensor units; and a flexible substrate comprising: a main body layer on which a plurality of third cavities for correspondingly accommodating the plurality of sensor units are arranged in an array; and the circuit carrier layer is arranged on one side, far away from the elastic recovery element, of the main body layer, and a circuit electrically connected with the pressure-sensitive element of the sensor unit is arranged on the circuit carrier layer.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a sensor unit and a flexible pressure sensor. Background Art

[0002] Flexible pressure sensors can detect pressure distribution on flat or curved surfaces, and are increasingly used in wearable devices, robot perception, and medical applications. Existing flexible pressure sensors include capacitive, piezoelectric, and piezoresistive types. Existing piezoresistive flexible pressure sensors are usually made by using process planar manufacturing technologies such as printing and deposition on flexible substrates to produce multiple resistor units. On the other hand, MEMS (micro-electromechanical systems)-based pressure-sensitive elements have been very successful and widely used in fluid pressure measurement, and their costs have been greatly reduced, but they have not been used in flexible pressure sensors. Summary of the invention

[0003] In view of the deficiencies of the prior art, the present application provides a sensor unit to measure pressure distribution using a MEMS pressure-sensitive element.

[0004] To achieve the above objectives, the present application provides a sensor unit, which includes:

[0005] A pressure-sensitive element having an elastic membrane extending laterally;

[0006] A pressure transmitting element having a pressure transmitting portion for receiving and transmitting longitudinal pressure to the elastic membrane toward the longitudinal proximal end side;

[0007] and an elastic restoring element, which is used to make the pressure transmitting element separate toward the longitudinal distal end or only abut against the elastic membrane when the longitudinal pressure is lower than a preset pressure.

[0008] Preferably, the edge of the pressure-sensitive element extends toward the longitudinal distal end to form a circle of support portion, and the support portion and the elastic membrane enclose a first cavity for at least partially accommodating the pressure-transmitting element.

[0009] Preferably, the edge of the pressure-sensitive element is bonded to the longitudinal proximal side of the elastic recovery element.

[0010] Preferably, the pressure transmitting element further comprises a pressure receiving portion fixed to a longitudinal distal end of the pressure transmitting portion, and a transverse cross-sectional area of ​​the pressure receiving portion is larger than a transverse cross-sectional area of ​​the pressure transmitting portion.

[0011] Preferably, the elastic restoring element is longitudinally spaced apart and arranged between the supporting portion and the pressure receiving portion, and is provided with a through hole allowing the pressure transmitting portion to pass longitudinally.

[0012] Preferably, the pressure transmission element is made of elastic material.

[0013] Preferably, the pressure-sensitive element further comprises a protective cover arranged on one side of the longitudinal proximal end of the elastic membrane, and a second cavity at least partially covering the elastic membrane is enclosed between the protective cover and the elastic membrane.

[0014] The present application also claims protection for a flexible pressure sensor, comprising:

[0015] A plurality of sensor units according to any one of claims 1 to 4;

[0016] And a flexible substrate, comprising: a main body layer, on which a plurality of third cavities for correspondingly accommodating a plurality of the sensor units are arranged in an array; a circuit carrier layer arranged on a side of the main body layer away from the elastic recovery element, on which a circuit electrically connected to the pressure-sensitive element of the sensor unit is arranged.

[0017] Preferably, the flexible substrate further comprises a pressure receiving layer arranged on a side of the flexible substrate away from the circuit carrier layer, and the protective layer abuts or presses against the pressure transmission element toward a side of the main body layer.

[0018] Preferably, the elastic recovery element is integrally connected to the chassis layer.

[0019] The flexible pressure sensor and its sensor unit of the present application can utilize a low-cost MEMS pressure chip to measure pressure loads, and have a simple structure and can effectively protect the MEMS pressure chip, and are particularly suitable for pressure measurement of robots. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a top view of a flexible pressure sensor according to a preferred embodiment;

[0021] Figure 2 A flexible pressure sensor according to a preferred embodiment of the present invention is provided along Figure 1 A cross-sectional view of a portion A shown in FIG.

[0022] Figure 3 The sensor unit of a preferred embodiment is Figure 1 A cross-sectional view of AA is shown;

[0023] Figure 4 A perspective view of a sensor unit according to a preferred embodiment;

[0024] Explanation of the accompanying drawings: 100, flexible pressure sensor; 111, pressure transmitting part; 112, pressure receiving part; 11, pressure transmitting element; 121, elastic membrane; 122a, upper end; 122b, lower end; 122, supporting part; 124, solder ball; 12a, cavity; 12, pressure sensitive element; 13a, cavity; 13, protective cover; 1, sensor unit; 201, electrical connecting part; 20, circuit; 211, elastic recovery element; 21a, cavity; 21, main layer; 22a, exposed part; 22b, exposed part; 22c, opening; 22, circuit carrier layer; 23a, cavity; 23, pressure receiving layer; 2, flexible substrate. DETAILED DESCRIPTION

[0025] The technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings. The following embodiments are exemplary and are only used to explain the present application, and cannot be interpreted as limiting the present application. In the following description, the same symbols are used to represent the same or equivalent elements, and repeated descriptions are omitted.

[0026] In the description of the present application, it should be understood that the terms "upper", "lower", "inner", "outer", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or the directions or positional relationships in which the products of the present application are usually placed when in use, or the directions or positional relationships usually understood by those skilled in the art, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the equipment or components referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limitations on the present application. In addition, the prepositive terms "first", "second", "third", etc. are only used to distinguish the modified objects, and cannot be understood as indicating or implying relative importance.

[0027] In addition, 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 or an electrical connection; it can be a direct connection or an indirect connection 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 this application can be understood according to specific circumstances.

[0028] It should be further understood that the term “and / or” used in the specification and corresponding claims of this application refers to any and all possible combinations of one or more of the listed items.

[0029] like Figure 1As shown. The flexible pressure sensor 100 includes a flexible substrate 2. The flexible substrate 2 is flexible as a whole, and each of its constituent layers is flexible, and it at least includes a main body layer 21 and a circuit carrier layer 22. Among them, a plurality of cavities 21a are arranged in an array on the main body layer 21. For example, the cavities 21a can be set to 20, which can be arranged in a 4×5 rectangular array. The plurality of cavities 21a correspondingly accommodate a plurality of sensor units 1. A circuit 20 is provided on the circuit carrier layer 22, and the circuit 20 is electrically connected to the sensor unit 1. The circuit 20 can be provided on the side of the circuit carrier layer 22 facing the circuit carrier layer 22, and the circuit 20 is electrically connected to each sensor unit 1 through a plurality of solder balls 124 formed by ball planting. The circuit 20 also includes a plurality of conductive traces (not shown) and a plurality of electrical connection parts 201 electrically connected to the conductive traces. The electrical connection parts 201 may be exposed outside the main layer 21 on one or both lateral sides to facilitate connection with an external controller. For example, these electrical connection parts 201 may be arranged on exposed parts 22a, 22b extending outward from the main layer 21 on opposite lateral sides of the circuit carrier layer 22; in some other inferior embodiments, the circuit 20 may also be arranged on a side of the circuit carrier layer 22 away from the main layer 21, and the sensor unit 1 may be electrically connected to the circuit 20 via leads.

[0030] The flexible pressure sensor 100 can be attached to a flat surface. When a flat pressure load P (which can be an uneven load) is applied to one side of the flexible pressure sensor 100, the longitudinal pressure (relative to each sensor unit 1) received by each of the multiple sensor units 1 is P i (where i=1-20). It is easy to understand that the flexible pressure sensor 100 can also be attached to a curved base. The presence and size distribution of these longitudinal pressures Pi can roughly characterize the presence and size distribution of the real pressure load P. The distribution of these pressures is in discrete form, and there may be some differences between them and the continuous distribution of the real pressure load. These differences are corrected by artificial intelligence algorithms, and the size of these pressures can also be corrected by the usual sensor calibration procedure.

[0031] Please refer to Figure 2-Figure 3 The sensor unit 1 includes a pressure-sensitive element 12, a pressure-transmitting element 11 and an elastic restoring element 211. The pressure-sensitive element 12 has an elastic membrane 121 extending laterally. The pressure-transmitting element 11 has a pressure-transmitting portion 111 for receiving and transmitting longitudinal pressure to the elastic membrane 121 toward the longitudinal proximal end. The pressure-transmitting portion 111 is preferably rod-shaped, with its longitudinal distal end ( Figure 3 The upper end of the i After that, the elastic restoring element 211 is compressed, and the longitudinal proximal end ( Figure 3 until P iIncrease to the preset pressure P 0 After that, the longitudinal proximal end of the pressure transmitting portion 111 abuts against and presses the elastic membrane 121 to cause deformation, thereby generating a corresponding pressure signal, and the measured pressure P is obtained. i '. When P i Increase to preset pressure P 0 Afterwards, the elastic restoring element 211 rebounds, and the longitudinal proximal end of the pressure transmitting portion 111 is separated from or only abuts against the elastic membrane 121, P i ' then drops to zero.

[0032] The size of the preset pressure P0 can be designed by the size and material properties of the elastic recovery element 211 and the pressure transmission element 11. 0 It can be set to a pressure greater than zero. At this time, only the longitudinal pressure P received by the sensor unit 1 i Increase to P 0 When the pressure is set to P, the corresponding pressure signal is generated, which can avoid noise interference; in particular, the preset pressure P 0 It can also be zero, that is, as long as the longitudinal pressure P i When it is not zero, the sensor unit 1 generates a corresponding non-zero measured pressure P i '.

[0033] Preferably, the pressure sensitive element 12 is a MEMS pressure chip made of semiconductor material, and its edge extends toward the longitudinal distal end to form a circle of support portion 122. A pressure measurement circuit may be formed on the longitudinal distal end of the elastic membrane 121. The pressure measurement circuit may have multiple semiconductor resistors forming a measurement bridge. The pressure measurement circuit may also include a longitudinal proximal end ( Figure 3 A plurality of solder pads are provided on the lower end 122b of the flexible pressure sensor 100, and the solder balls 124 can be provided on the solder pads. The support portion 122 and the elastic membrane 121 enclose a cavity 12a for at least partially accommodating the pressure transmitting element 11. A suitable gap can be left between the pressure transmitting portion 111 and the inner wall of the cavity 12a to guide the pressure transmitting portion 111 in the longitudinal direction and to prevent the pressure transmitting portion 111 from being excessively tilted when the flexible pressure sensor 100 is bent, so that the longitudinal proximal end thereof generates an excessive lateral displacement when the elastic membrane 121 is pressed. The longitudinal distal end ( Figure 3 The upper end 122a) in the middle can be bonded to the longitudinal proximal side of the elastic recovery element 211.

[0034] Preferably, the pressure transmission element 11 further comprises a pressure receiving portion 112 fixed to the longitudinal distal end of the pressure transmission portion 111. The transverse cross-sectional area of ​​the pressure receiving portion 112 is larger than the transverse cross-sectional area of ​​the pressure transmission portion 111. The elastic recovery element 211 is longitudinally spaced between the support portion 122 and the pressure receiving portion 112, and is provided with a through hole that allows the pressure transmission portion 111 to pass longitudinally. In this way, the longitudinal pressure Pi A portion of the pressure is supported by the elastic restoring element 211 and offset, and only a portion of the pressure is applied to the elastic membrane 121, thereby enabling the sensor unit 1 to measure a larger longitudinal pressure.

[0035] Preferably, the pressure transmitting element 11 may be made of an elastic material. The pressure load P is directly loaded on the longitudinal distal end of the pressure receiving portion 112 .

[0036] Preferably, the pressure-sensitive element 12 may further include a protective cover 13 covering the longitudinal proximal side of the elastic membrane 121. A cavity 13a that at least partially covers the elastic membrane 121 is formed between the protective cover 13 and the elastic membrane 121, thereby providing mechanical protection for the longitudinal proximal side of the elastic membrane 121. The cavity 13a may also be a closed cavity, in which a reference pressure cavity with a certain reference pressure may be formed. In particular, the cavity 13a is a vacuum cavity. The circuit carrier layer 22 may be provided with an opening 22c that at least partially accommodates the protective cover 13. Figure 4 As shown, the solder balls 124 may be disposed on one lateral side or two opposite sides of the protection cover 13 to avoid the protection cover 13 .

[0037] Preferably, the flexible substrate 2 further comprises a pressure receiving layer 23 disposed on the side of the flexible substrate 2 away from the circuit carrier layer 22. The protective layer 23 abuts or presses against the pressure transmitting element 11 toward the side of the main body layer 21, and the pressure load P is indirectly loaded on the longitudinal distal end of the pressure receiving portion 112 through the pressure receiving layer 23. A cavity 23a for at least partially accommodating the pressure receiving portion 112 is formed in the pressure receiving layer 23, and the cavity 23a can be formed by cutting the pressure receiving layer 23, or by compressing the pressure receiving portion 112 toward the longitudinal distal end. In addition, the flexible substrate 2 can further comprise a protective layer (not shown) attached to the side of the circuit carrier layer 22 away from the main body layer 21.

[0038] Preferably, the edge of the elastic recovery element 211 may be integrally connected to the main body layer 21 .

[0039] The pressure receiving layer 23, the main body layer 21, and the protective layer may be made of silicone, rubber, fabric, or other flexible materials. The pressure transmitting element 11 may be made of silicone, rubber, plastic, or other suitable elastic materials. The circuit carrier layer 22 may be made of polyimide, polyester, or other materials.

[0040] The scope of the disclosure is defined not by the detailed description but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are construed as being included in the disclosure.

Claims

1. A sensor unit, characterized in that: include: A pressure-sensitive element (12) having an elastic membrane (121) extending laterally; A pressure transmission element (11) having a pressure transmission portion (111) for receiving and transmitting longitudinal pressure toward the longitudinal proximal end side of the elastic membrane (121); and an elastic recovery element (211) for causing the pressure transmission element (11) to separate toward the longitudinal distal end or only abut against the elastic membrane (121) when the longitudinal pressure is lower than a preset pressure.

2. The sensor unit according to claim 1, characterized in that The edge of the pressure-sensitive element (12) extends toward the longitudinal distal end to form a circle of support portion (122), and the support portion (122) and the elastic membrane (121) enclose a first cavity (12a) for at least partially accommodating the pressure-transmitting element (11).

3. The sensor unit according to claim 1, characterized in that The edge of the pressure-sensitive element (12) is bonded to the longitudinal proximal side of the elastic recovery element (211).

4. The sensor unit according to claim 2, characterized in that The pressure transmission element (11) further comprises a pressure receiving portion (112) fixed to the longitudinal distal end of the pressure transmission portion (111), and the transverse cross-sectional area of ​​the pressure receiving portion (112) is larger than the transverse cross-sectional area of ​​the pressure transmission portion (111).

5. The sensor unit according to claim 4, characterized in that The elastic recovery element (211) is longitudinally spaced apart and arranged between the support portion (122) and the pressure receiving portion (112), and is provided with a through hole that allows the pressure transmitting portion (111) to pass longitudinally.

6. The sensor unit according to any one of claims 1 to 5, characterized in that The pressure transmission element (11) is made of elastic material.

7. The sensor unit according to any one of claims 1 to 5, characterized in that The pressure-sensitive element (12) further comprises a protective cover (13) which is arranged on one side of the longitudinal proximal end of the elastic membrane (121), and a second cavity (13a) which at least partially covers the elastic membrane (121) is formed between the protective cover (13) and the elastic membrane (121).

8. A flexible pressure sensor (100), characterized in that: include: A plurality of sensor units (1) according to any one of claims 1 to 7; and a flexible substrate (2), comprising: a main body layer (21), on which a plurality of third cavities (21a) for correspondingly accommodating a plurality of the sensor units (1) are arranged in an array; A circuit carrier layer (22) is arranged on the side of the main body layer (21) away from the elastic recovery element (211), and a circuit (20) electrically connected to the pressure sensitive element (12) of the sensor unit (1) is arranged on the circuit carrier layer (22).

9. The flexible pressure sensor (100) according to claim 8, characterized in that: The flexible substrate (2) further comprises a pressure receiving layer (23) arranged on a side of the flexible substrate (2) away from the circuit carrier layer (22), and the protective layer (23) abuts or presses against the pressure transmission element (11) towards a side of the main body layer (21).

10. The flexible pressure sensor (100) according to any one of claims 1 to 9, characterized in that: The elastic recovery element (211) is integrally connected to the main body layer (21).

Images