CN216284034U - Pressure detection module and electronic equipment - Google Patents

Abstract

The embodiment of the application provides a pressure detection module and electronic equipment. This pressure detection module includes: a pressure sensor and a circuit board; the pressure sensor comprises a substrate, a first bonding pad and a sensing unit, wherein the first bonding pad and the sensing unit are arranged on the substrate; the circuit board is provided with a second bonding pad, and the pressure sensor is electrically connected with the circuit board by welding the first bonding pad and the second bonding pad, so that the pressure detection module has a compact structure and a small volume, and can be suitable for electronic equipment with a narrow internal space; the second pad is provided with a soldering tin through hole, and redundant soldering tin can flow to the other side of the circuit board through the soldering tin through hole, so that the short circuit caused by the bonding of the pad due to the redundant soldering tin is avoided, and the welding yield is improved; a preset interval for dispensing is arranged between the first bonding pad and the edge of the substrate.

Description

Pressure detection module and electronic equipment

Technical Field

The embodiment of the application relates to the technical field of sensors, in particular to a pressure detection module and electronic equipment.

Background

A pressure detection device is widely used in various electronic apparatuses as a device for detecting pressure. The electronic device detects whether it is pressed by a pressure detection device installed inside, and performs operation control corresponding to the pressing. For example, a pressure detection device is correspondingly installed inside a key of the mobile phone to determine whether the key is pressed, so as to control a switch of the mobile phone.

In the related art, a pressure sensing assembly of the pressure detection apparatus is electrically connected to a circuit board, and the pressure sensing assembly converts sensed pressure into an electrical signal and transmits the electrical signal to the circuit board. The internal space of the electronic device is usually very narrow, and the pressure-sensitive component is usually soldered to the circuit board to achieve electrical connection.

However, during the soldering process, the melted excess solder overflows the pads, causing the pads to stick, resulting in short circuits and defective products.

SUMMERY OF THE UTILITY MODEL

The application provides a pressure detection module and electronic equipment to when solving current forced induction subassembly and circuit board welding, unnecessary soldering tin leads to the short circuit easily and influences the technical problem of product yield.

In order to achieve the above purpose, the embodiments of the present application adopt the following technical solutions:

in a first aspect, an embodiment of the present application provides a pressure detection module, including: a pressure sensor and a circuit board; the pressure sensor comprises a substrate, a first bonding pad and a sensing unit, wherein the first bonding pad and the sensing unit are arranged on the substrate; the sensing unit is used for sensing pressure and converting the pressure into an electric signal; a second bonding pad is arranged on the circuit board, and a soldering tin through hole penetrating through the thickness direction of the circuit board is arranged on the second bonding pad; the second bonding pad is welded with the first bonding pad; and a preset interval for dispensing is arranged between the first bonding pad and the edge of the substrate.

Compared with the prior art, the pressure detection module that the first aspect of this application embodiment provided has following advantage:

the pressure detection module provided by the embodiment of the application comprises a pressure sensor and a circuit board, wherein the pressure sensor is electrically connected with the circuit board by welding a first bonding pad of the pressure sensor with a second bonding pad of the circuit board, so that the pressure detection module is compact in structure, small in size and suitable for electronic equipment with narrow internal space; and be provided with the soldering tin via hole on the second pad, unnecessary soldering tin can flow to the another side of circuit board through the soldering tin via hole to avoid unnecessary soldering tin to lead to the pad adhesion and short circuit, thereby improve the welding yield. The utility model provides a soldering tin via hole is located the second pad, and unnecessary soldering tin can directly flow out, need not to set up the guiding gutter, is favorable to simplifying the structure of circuit board to can discharge soldering tin in time, avoid the untimely and overflow over the pad of soldering tin discharge.

As a possible implementation manner, a plurality of second pads are arranged on the circuit board, and each second pad is provided with one solder via hole; the substrate is provided with a plurality of first bonding pads, and each first bonding pad is welded with one second bonding pad.

As a possible embodiment, the first pad is rectangular; the length of the first bonding pad is greater than or equal to 0.2mm, and the width of the first bonding pad is greater than or equal to 0.2 mm.

As a possible implementation manner, the first pads are arranged in a matrix on the substrate, and the interval between two adjacent first pads is greater than or equal to 0.2 mm.

As a possible embodiment, the substrate is rectangular; the induction unit comprises a first induction column and a second induction column which are arranged at intervals along the length direction of the substrate, and a welding area is formed between the first induction column and the second induction column; the first bonding pad is located within the bonding area.

As a possible implementation manner, at least four first pads are arranged on the substrate, two rows of the first pads are arranged at intervals along the width direction of the substrate, and each row of the first pads comprises two first pads arranged at intervals along the length direction of the substrate; the preset interval is arranged between one row of the first bonding pads and the edge of the substrate close to the first bonding pads.

As a possible embodiment, said preset interval is greater than or equal to 0.25 mm.

As a possible implementation, the first sensing column includes a first strained gate and a second strained gate which are arranged at intervals; the second induction column comprises a third strain gate and a fourth strain gate which are arranged at intervals; the first strain gate, the second strain gate, the third strain gate and the fourth strain gate form a full-bridge series circuit; the first pad is arranged on a series line between the first strain gate and the third strain gate, the first pad is arranged on a series line between the third strain gate and the second strain gate, the first pad is arranged on a series line between the second strain gate and the fourth strain gate, and the first pad is arranged on a series line between the fourth strain gate and the first strain gate.

As a possible implementation, the resistance deviation of the first strained gate, the second strained gate, the third strained gate, or the fourth strained gate is less than or equal to 10%.

As a possible implementation manner, at least three positioning notches are arranged on the circuit board, and the at least three positioning notches are arranged in a triangular shape; at least three positioning marks are arranged on the substrate, and each positioning mark is opposite to one positioning notch.

As a possible implementation manner, four positioning notches are arranged on the circuit board, and the four positioning notches are arranged in a matrix; the base plate is provided with four positioning marks which are arranged in a matrix.

As a possible implementation, the pressure detection module further includes a cantilever sheet, and the cantilever sheet has a strain area and a force-receiving area; one surface of the substrate, which is far away from the circuit board, is attached to the strain area.

As a possible implementation mode, the thickness of the cantilever beam sheet is 0.2-2 mm.

As a possible embodiment, the thickness of the cantilever beam piece is 0.5 mm.

As a possible embodiment, the cantilever beam piece has a thickness deviation of ± 25 μm.

In a second aspect, an embodiment of the present application provides an electronic device, which includes a main control chip and the pressure detection module described in the first aspect or any optional manner of the first aspect, where the main control chip is electrically connected to a circuit board of the pressure detection module.

The electronic device provided by the embodiment of the application also has the same advantages as the pressure detection module of the first aspect because the electronic device comprises the pressure detection module of the first aspect.

In addition to the technical problems solved by the present application, the technical features constituting the technical solutions, and the advantages brought by the technical features of the technical solutions described above, other technical problems that can be solved by the pressure detection module and the electronic device provided by the present application, other technical features included in the technical solutions, and advantages brought by the technical features will be further described in detail in the detailed description of the present application.

Drawings

FIG. 1a is a top view of a prior art resistive pressure sensing device;

FIG. 1b is a side view of FIG. 1 a;

FIG. 1c is a schematic diagram of a full bridge circuit of the strain gauge;

fig. 2 is a schematic structural diagram of a pressure detection module according to an embodiment of the present disclosure;

FIG. 3 is a schematic structural diagram of the circuit board of FIG. 2;

FIG. 4 is a schematic structural diagram of the pressure sensor of FIG. 2;

FIG. 5 is a schematic view of the pressure sensor of FIG. 4 with the cover layer and the water-proof layer removed;

fig. 6 is a schematic structural diagram of a pressure detection module according to a second embodiment of the present disclosure;

fig. 7 is a schematic circuit diagram of a pressure detection module according to an embodiment of the present disclosure;

fig. 8 is a schematic structural diagram of a pressure detection calibration apparatus according to an embodiment of the present disclosure;

FIG. 9 is a schematic structural diagram of another pressure detection calibration apparatus provided in the embodiments of the present application;

fig. 10 is a schematic structural diagram of another pressure detection calibration apparatus according to an embodiment of the present application.

Description of reference numerals:

10: a strain gauge; 1: a resistance; 2: welding a disc; 3: a base plate; 6: a cantilever beam; 61: a through hole; 5: a cover layer;

41: an object stage; 42: a sleeve; 421: a ball bearing; 422: a fixed part; 43: a slide bar; 44: a weight; 45: pressing a key; 46: a soft silicone block; 47: a force sensor;

100: a pressure sensor; 110: a substrate; 111: a welding area; 120: a first pad; 130: a sensing unit; 131: a first sensing column; 1311: a first strain gate; 1312: a second strained gate; 132: a second sensing column; 1321: a third strain gate; 1322: a fourth strain gate; 140: a protective layer; 150: presetting intervals; 160: positioning a scale; 170: a waterproof glue layer; 200: a circuit board; 210: a second pad; 211: soldering a through hole; 220: positioning the notch; 300: a cantilever beam piece; 310: a strained region; 320: a force-bearing area.

Detailed Description

In the prior art, the electrical connection between the pressure sensing component of the pressure detection device and the circuit board is often realized by welding. However, during the soldering process, the melted excess solder overflows the pads, so that the pads are easily adhered, and short circuit is caused to form an unqualified product.

FIG. 1a is a top view of a prior art resistive pressure sensing device; FIG. 1b is a side view of FIG. 1 a.

The resistive pressure detecting apparatus shown in fig. 1a includes a strain gauge 10 and a cantilever beam 6, and one strain gauge 10 may be disposed on each of two opposite side surfaces of the cantilever beam 6.

Based on fig. 1b, the present embodiment may provide the strain gauge 10 on only one surface of the cantilever beam 6. The number of the resistors in the strain gauge arranged on one surface of the cantilever beam can be twice the number of the resistors in the strain gauge respectively arranged on two side surfaces of the cantilever beam, so that the number of the strain gauges can be reduced on the premise of ensuring the pressure detection precision, and the number of the bonding process, the lead process and the like can be reduced by half, thereby being beneficial to reducing the cost and improving the process efficiency.

Referring to fig. 1c, fig. 1c is a schematic diagram of a full bridge circuit of the strain gauge. The strain gauges form a full-bridge circuit for pressure detection, common-mode interference and temperature change generate the same signals on two bridge arms (the two bridge arms are R1 and R2, R3 and R4 respectively), two output electrodes (Sig + and Sig-) of the signals can be mutually offset, only the pressing signals are reserved, and the anti-interference capability of pressure sensor detection is improved. The strain gauge can be provided with only one resistor, and then three resistors are used outside the strain gauge to form a full-bridge circuit, or four strain gauges are used to form a full-bridge circuit. A half-bridge strain gauge is provided with two resistors, and then the two resistors are arranged outside the strain gauge to form a full-bridge circuit. Alternatively, a full bridge circuit is formed using two half-bridge strain gages. Therefore, the laminating times are multiple, and the laminating tolerance influences the pressure detection precision; when the resistors of each strain gauge are connected into a full-bridge circuit, excessive welding operation is required, and the full-bridge circuit is not suitable for electronic equipment with narrow space.

With reference to fig. 1a and 1b, in the embodiment of the present application, the strain gauge 10 includes a bottom plate 3, four resistors 1 (corresponding to R1, R2, R3, and R4 in fig. 1c, respectively) disposed on the bottom plate 3, and a cover 5 covering the resistors 1, wherein the four resistors 1 form a full bridge circuit. The resistance values and the temperature coefficients of the four resistors 1 are set to be consistent, the positions of the four resistors 1 on the bottom plate 3 can be close to each other, the influence of the ambient temperature is the same, the two output electrodes (Sig + and Sig-) of the signals can be mutually offset, and the resistance value change caused by the temperature change cannot interfere with the pressing signal. The laminating that so sets up only need a foil gage, and easy operation is convenient, and occupation space is little.

In electronic equipment with a small internal space, the pressure sensor is usually soldered to a circuit board. With continuing reference to fig. 1a, four bonding pads 2 are further disposed on the bottom plate 3 of the strain gauge 10 and respectively bonded to the bonding pads of the circuit board. The four bonding pads 2 correspond to the VCC terminal, the ground terminal, the Sig + terminal, and the Sig-terminal in fig. 1c, respectively.

In the prior art, four bonding pads 2 are arranged in a row along the width direction of the bottom plate 3, so that after the circuit board is welded, no enough glue dispensing space exists on the strain gauge, the bonding pads are not convenient to be subjected to glue dispensing protection, the bonding pads 2 are exposed, and the bonding pads 2 and the leads near the bonding pads 2 are easily corroded by impurities such as water vapor.

In view of this, this application embodiment can set up four welding discs into the mode of arranging of two rows and two to four welding discs biasing are close to one edge of bottom plate, make another edge of bottom plate have some glue spaces, make things convenient for some glue guns to stretch into some glue, carry out water proof protection to welding disc region, avoid connecting the inefficacy.

In order to avoid unnecessary soldering tin to spill over and lead to the bonding of soldering pan, this application embodiment is provided with the soldering tin via hole on the soldering pan of circuit board to make unnecessary soldering tin flow out, make difficult to take place even tin between the soldering pan, thereby improve the welding yield.

Reference will now be made in detail to the embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar components or components having the same or similar functions. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application.

Fig. 2 is a schematic structural diagram of a pressure detection module according to an embodiment of the present disclosure. FIG. 3 is a schematic structural diagram of the circuit board of FIG. 2; FIG. 4 is a schematic structural diagram of the pressure sensor of FIG. 2; fig. 5 is a schematic structural view of the pressure sensor of fig. 4 with the cover layer and the waterproof layer removed.

With reference to fig. 2, an embodiment of the present application provides a pressure detection module, which includes: pressure sensor 100 and circuit board 200, pressure sensor 100 is used for converting the pressure signal into the electrical signal, and transmits the electrical signal to circuit board 200.

Referring to fig. 4 and 5, the pressure sensor 100 includes a substrate 110, and a first pad 120 and a sensing unit 130 disposed on the substrate 110, the first pad 120 being electrically connected to the sensing unit 130. The substrate 110 is used for carrying the first pad 120 and the sensing unit 130, and the substrate 110 may be made of polyimide or the like. The sensing unit 130 is used for sensing pressure and converting the pressure into an electrical signal, and the electrical signal is transmitted to the circuit board 200 through the first pad 120; the first pads 120 have a predetermined interval for dispensing with the edge of the substrate 110. The sensing unit 130 may be made of constantan or illion copper.

Optionally, the sensing unit 130 is covered with a protection layer 140, and the protection layer 140 may be a silicon gel layer to protect the sensing unit 130 from water. In the embodiment of the application, the thickness of the protective layer 140 is less than or equal to 5 μm, so that the problem of insufficient soldering during pad soldering caused by overlarge thickness of the protective layer 140 is avoided.

Referring to fig. 3, the circuit board 200 is provided with a second pad 210, and the second pad 210 is soldered to the first pad 120, so that the electrical signal sensed by the sensing unit 130 is transmitted to the circuit board 200. Optionally, the Circuit board 200 is a Flexible Printed Circuit (FPC) to prevent the Circuit board 200 from damaging the sensing unit 130 during soldering.

Optionally, the second pad 210 and the first pad 120 are soldered by hot-pressing and melting tin, so that the connection is stable and reliable, and the method can be applied to connection of smaller and thinner pads.

Optionally, the second pad 210 disposed on the circuit board 200 penetrates through the thickness direction of the circuit board 200, and thus, when the second pad 210 is soldered to the first pad 120, heat can be transferred to the other side of the circuit board 200 through the second pad 210, so as to perform a heat transfer function.

In the embodiment of the present application, the second pad 210 is provided with the solder via 211 penetrating through the thickness direction of the circuit board 200, so that the excessive solder between the second pad 210 and the first pad 120 can directly flow out to the other side of the circuit board 200 through the solder via 211 without overflowing from the second pad 210 or the first pad 120, thereby avoiding the excessive solder from remaining between the circuit board 200 and the pressure sensor 100, and causing adhesion between the second pads 210 or between the first pads 120, which is beneficial to improving the welding yield.

The solder via hole 211 may be a circular hole, a square hole, an elliptical hole, etc., which is not limited in the embodiment of the present application. In addition, the size of the cross-sectional area of the solder via 211 is not limited in the embodiment of the present application, and a person skilled in the art can limit the size according to the actual size of the second pad 210, so that it should be avoided that the stability of the connection between the second pad 210 and the first pad 120 is affected by the too large cross-sectional area of the solder via 211, and it should also be avoided that the solder cannot flow out due to the too small cross-sectional area of the solder via 211.

Optionally, the solder via 211 is disposed at a center of the second pad 210, so that the excess solder can uniformly flow into the solder via 211, and the solder via 211 is prevented from being offset to cause a portion of the solder to overflow the second pad 210. Illustratively, the second pad 210 is square, the solder via 211 is a circular hole, and the solder via 211 is disposed at a center of the square second pad 210.

With reference to fig. 3, when the circuit board 200 is provided with a plurality of second pads 210, each second pad 210 is provided with a solder via hole 211, so that the excess solder in each second pad 210 can flow out through the corresponding solder via hole 211, and the soldering yield is further improved.

With reference to fig. 4 and 5, a plurality of first pads 120 are disposed on the substrate 110, and the plurality of first pads 120 are arranged in a matrix on the substrate 110; accordingly, the plurality of second pads 210 are arranged in a matrix on the circuit board 200, and the number of the second pads 210 is the same as that of the first pads 120. Each of the first pads 120 is soldered to one of the second pads 210.

In the embodiment of the present application, four first pads 120 are provided, two rows of first pads are disposed at intervals along the width direction of the substrate 110, each row of first pads includes two first pads 120 disposed at intervals along the length direction of the substrate 110, that is, the four first pads 120 are arranged in a rectangular shape on the substrate 110. Correspondingly, there are four second pads 210, and the four second pads 210 are arranged in a rectangular shape on the circuit board 200. The four second pads 210 are respectively connected to the voltage VCC, the ground terminal, and two signal transmission terminals of the inspection chip on the circuit board 200.

Optionally, the first pad 120 is rectangular. The length of the first pad 120 is greater than or equal to 0.2mm, and the width of the first pad 120 is greater than or equal to 0.2 mm. By such an arrangement, the increase of the process difficulty caused by the too small size of the first bonding pad 120 can be avoided, and the welding yield is further improved.

Optionally, the interval between two adjacent first pads 120 is greater than or equal to 0.2mm, so as to avoid that the first pads 120 are easy to adhere due to an excessively small interval.

Alternatively, the size of the second pads 210 is the same as the shape and size of the first pads 120, and the interval between two adjacent second pads 210 is the same as the interval between two adjacent first pads 120.

Through the above limitation on the size of the first bonding pad 120 and the interval size of the adjacent first bonding pads 120, the difficulty of hot-press welding is reduced, and the welding yield is improved.

With continued reference to fig. 4 and 5, in some implementations, the substrate 110 is rectangular. The sensing unit 130 includes a first sensing column 131 and a second sensing column 132 arranged at intervals along a length direction of the substrate 110, and a welding region 111 is formed between the first sensing column 131 and the second sensing column 132; all of the first pads 120 are located within the bonding region 111, that is, all of the first pads 120 are located between the first sensing column 131 and the second sensing column 132. The four first pads 120 are arranged in a rectangular shape in the bonding region 111.

A predetermined interval 150 for dispensing is provided between the first pad of one row and the edge of the substrate 110 near the first pad of the row, and a predetermined interval 150 is provided between the first pad of the upper row and the upper edge of the substrate 110 in the direction shown in fig. 5.

Of course, the first pads of the lower row may have a predetermined interval from the lower edge of the substrate 110.

Optionally, the preset interval is greater than or equal to 0.25mm, so that a dispensing space is formed between the circuit board 200 and the pressure sensor, the dispensing head can conveniently extend into the dispensing head for dispensing, and the glue can flow to all the bonding pads. Therefore, the waterproof glue layer 170 can be formed in the welding area 111, and the phenomenon that the bonding pad and the lead near the bonding pad are corroded by water vapor to cause failure is avoided.

It should be noted that the waterproof adhesive layer 170 may not only cover the pad, and in actual operation, the waterproof adhesive layer 170 may extend onto the protective layer 140 due to the flowing of the glue, and the shape of the waterproof adhesive layer 170 shown in the drawings is only schematically illustrated, and is not a limitation on the shape of the waterproof adhesive layer 170.

In the embodiment of the present application, the first sensing column 131 and the second sensing column 132 are used for sensing pressure. The sensing unit 130 of the embodiment of the present application is a full bridge circuit, and accordingly, the first sensing column 131 includes a first strain gate 1311 and a second strain gate 1312 spaced apart from each other in the width direction of the substrate 110, and the second sensing column 132 includes a third strain gate 1321 and a fourth strain gate 1322 spaced apart from each other in the width direction of the substrate 110. The first, second, third and fourth strain gates 1311, 1312, 1321 and 1322 form a full bridge series loop.

A first pad 120 is disposed in a series line between the first strain gate 1311 and the third strain gate 1321, a first pad 120 is disposed in a series line between the third strain gate 1321 and the second strain gate 1312, a first pad 120 is disposed in a series line between the second strain gate 1312 and the fourth strain gate 1322, and a first pad 120 is disposed in a series line between the fourth strain gate 1322 and the first strain gate 1311.

In the embodiment of the present application, based on the directions shown in fig. 5, the two first pads 120 on the left side are used for connecting the VCC voltage and the ground, respectively, and the two first pads 120 on the right side are used for connecting Sig + and Sig-for signal transmission, respectively. Alternatively, the two first pads 120 on the left side are used to connect Sig + and Sig-for signal transmission, respectively, and the two first pads 120 on the right side are used to connect VCC voltage and ground, respectively.

In the orientation shown in fig. 5, the upper left first pad 120 is adjacent to the first strain gate 1311, and the upper right first pad 120 is adjacent to the third strain gate 1321; the lower left first pad 120 is adjacent to the second strain gate 1312, the lower right first pad 120 is adjacent to the fourth strain gate 1322, and the series line between the first strain gate 1311 and the fourth strain gate 1322 is routed from the outside of the third strain gate 1321 to the lower right first pad 120. Of course, the connection relationship between the four strain gates and the four first pads 120 is not limited to that shown in fig. 5.

The shapes of the first strained gate 1311, the second strained gate 1312, the third strained gate 1321 and the fourth strained gate 1322 may be S-shaped as shown in fig. 5, or rectangular, square-shaped, and the like, and the embodiment of the present invention is not limited herein.

The resistances of the first strain gate 1311, the second strain gate 1312, the third strain gate 1321 and the fourth strain gate 1322 correspond to the resistances of R1, R2, R3 and R4 in fig. 1c, respectively. The resistance deviation of each of the first, second, third and fourth strain gates 1311, 1312, 1321 and 1322 is less than or equal to 10%, which may result in a pressure signal attenuation of less than 1%. The zero offset Voffset to ground is 10% of Vcc, within the dynamic range of the detection chip on board 200. The resistance deviation is the difference between the theoretical resistance value and the actual resistance value of the strain gate.

Some electronic devices, such as mobile phones, have a limited battery capacity, and the resistance of the pressure sensor of the embodiment of the present application is typically only a few hundred ohms. If the sensing unit 130 is powered by the direct current Vcc, the power consumption is excessive, and the standby time and the use time of the device are reduced. In the embodiment of the application, a pulse output mode can be adopted to intermittently output Vcc so as to achieve the purpose of reducing power consumption.

Fig. 7 is a schematic circuit diagram of a pressure detection module according to an embodiment of the present disclosure. Fig. 7 shows a circuit using NMOS as a power supply switch, but PMOS may be selected as the power supply switch.

During the soldering process between the circuit board 200 and the pressure sensor 100, the circuit board 200 covers the pressure sensor 100 underneath, so that the second pads 210 and the first pads 120 cannot be directly aligned, resulting in low soldering yield. For this, the embodiment of the present application provides the positioning structure on the circuit board 200 and the substrate 110 so that the second pads 210 can be aligned with the first pads 120.

Specifically, referring to fig. 3 and 4, at least three positioning notches 220 are disposed on the circuit board 200, and the at least three positioning notches 220 are arranged in a triangular shape, that is, the positioning notches 220 form a positioning surface on the circuit board 200, so that all the positioning notches 220 are prevented from being arranged at intervals along a preset direction to form a line.

Correspondingly, at least three positioning marks 160 are disposed on the substrate 110, and each positioning mark 160 is opposite to one positioning notch 220. Referring to fig. 2, when the circuit board 200 is stacked on the substrate 110, the positioning notch 220 may correspondingly display the positioning mark 160 therebelow, and the positioning mark 160 is exposed in the positioning notch 220, such that the second pad 210 is aligned with the first pad 120.

Optionally, when the strain gate is formed on the substrate 110, the positioning mark 160 is formed at the same time, so that the process is simple and the cost is low.

It should be noted that in the embodiment of the present application, the protection layer 140 may cover not only the four strained gates, but also the connection lines of the strained gates and the positioning targets 160 to protect them.

In a specific implementation manner, four positioning notches 220 are arranged on the circuit board 200, and the four positioning notches 220 are arranged in a matrix; correspondingly, four positioning targets 160 are disposed on the substrate 110 in a matrix arrangement.

Optionally, the positioning notch 220 is disposed at the edge of the circuit board 200, so as to avoid the electric devices of the circuit board 200, and the positioning mark 160 is disposed at the edge of the substrate 110 so as to avoid the arrangement of the sensing unit 130 and the first pad 120.

Alternatively, the positioning notch 220 may be a rectangular notch, and correspondingly, the positioning mark 160 is a rectangular mark.

Due to the small size of the positioning notches 220 and the positioning marks 160, if only one pair of positioning notches 220 and positioning marks 160 is provided, the second pads 210 and the first pads 120 are still difficult to align. For this reason, in the embodiment of the present application, the positioning notch 220 and the positioning mark 160 are provided in plural. Of course, the shape of the positioning notch 220 and the positioning mark 160 is not limited to the rectangle shown in the figure, and the positioning notch 220 and the positioning mark 160 may also be a circle, an ellipse, etc.

Referring to fig. 1b, in the prior art, the cantilever beam 6 is provided with a through hole 61 for concentrating stress and facilitating stress detection, and the strain gauge 10 is attached to the surface of the cantilever beam 6 corresponding to the through hole 61. However, this structure results in a relatively large volume of the pressure detection device, which is not suitable for electronic equipment with a small space size.

Fig. 6 is a schematic structural diagram of a pressure detection module according to a second embodiment of the present application.

With reference to fig. 6, the pressure detection module provided in the embodiment of the present application further includes a cantilever sheet 300, the cantilever sheet 300 has a strain region 310 and a stress region 320, and a surface of the substrate 110 facing away from the circuit board 200 is attached to the strain region 310. The force-bearing area 320 is connected to a force transmission member, wherein the force transmission member may be a spring, a thimble, a silica gel pad, or the like; the cantilever beam 300 may be a thin plate-like structure made of metal such as stainless steel or aluminum alloy. The stress is greatest at the strained region 310 when the stressed region 320 is under stress. Optionally, the strain region 310 of the cantilever beam 300 is determined by finite element simulation methods.

Optionally, the thickness of the cantilever beam piece 300 is 0.2-2 mm, for example, the thickness of the cantilever beam piece 300 is 0.5mm, which avoids the problem that the cantilever beam piece 300 is too small in thickness, so that the strength is low and the cantilever beam piece is easy to damage.

Optionally, the thickness deviation of the cantilever beam 300 is ± 25 μm, so that the pressure accuracy is within 1%. The thickness of the cantilever beam piece 300 is more uniform, and the pressure detection precision is more favorably improved.

Alternatively, the width of the cantilever beam 300 may be 3mm and the length 6mm, but this is not limitative.

The cantilever beam piece 300 of the embodiment of the application is of a sheet structure, is not provided with a through hole, is small in thickness, and is conveniently applied to electronic equipment with small space size.

The embodiment of the application further provides an electronic device, which comprises a main control chip and the pressure detection module, wherein the main control chip is electrically connected with the circuit board of the pressure detection module. The main control chip is used for receiving the pressing signal of the circuit board so as to execute the function corresponding to the pressing signal.

The structure, function, and effect of the pressure detection module provided in the embodiment of the present application are the same as those of the above embodiment, and the above embodiment may be specifically referred to, and are not repeated herein.

The electronic device may be any suitable electronic device that requires pressure detection, including but not limited to a cell phone, headset, watch, tablet, wearable device, electric toothbrush, remote control, e-cigarette, etc.

The pressure detection module that this application embodiment provided, the precision is high, small, low power dissipation, can be applied to blood pressure detection's electronic equipment's button.

The electronic device according to the embodiment of the present application includes the pressure detection module, so that the electronic device according to the embodiment of the present application also has the same advantages as the pressure detection module.

Fig. 8 is a schematic structural diagram of a pressure detection calibration apparatus according to an embodiment of the present disclosure; FIG. 9 is a schematic structural diagram of another pressure detection calibration apparatus provided in the embodiments of the present application; fig. 10 is a schematic structural diagram of another pressure detection calibration apparatus according to an embodiment of the present application.

Fig. 8 is a schematic structural diagram of a pressure detection calibration apparatus according to an embodiment of the present application. The calibration device for pressure detection comprises a stage 41, a sleeve 42, a sliding rod 43 and a weight 44, wherein the sleeve 42 further comprises a ball 421 and a fixing part 422. The slide rod 43 is sleeved inside the sleeve 42, the stage 41 is arranged above the slide rod 43, the weight 44 can be stably placed on the stage 41, the balls 421 inside the sleeve 42 can reduce the friction force when the slide rod 43 slides up and down inside the sleeve 42, and the fixing portion 422 of the sleeve 42 can be used for external fixation. The pressure button 45 is under the sliding rod 43, and when the friction force between the sleeve 42 and the sliding rod 43 is zero, the pressure applied to the pressure button 45 is the weight of the sliding rod 43 plus the weight 44.

However, in practical use, since it is difficult to make the lower surface of the sliding rod 43 and the upper surface of the press key 45 completely horizontal, the press key 45 will give a lateral pushing force to the sliding rod 43 when being stressed, so that the friction of the sliding rod 43 inside the sleeve 42 is greatly increased.

To solve this problem, a soft silicone block 46 may be added to the bottom of the sliding bar 43, as shown in fig. 9; in particular, the soft silicone block 46 may have a hardness of about 40, i.e., close to the hardness of a human finger. It will be appreciated that the soft silicone block 46 could be replaced by a pressing head of other material and hardness to achieve the same effect.

Furthermore, since the friction between the sleeve 42 and the sliding rod 43 is objective and cannot be completely eliminated, even if lubricant is applied to the sleeve 42 or a pressing head (such as a soft silica gel block 46) is added to the bottom of the sliding rod 43, the friction cannot be completely eliminated, which results in that the pressure applied to the pressure button 45 is not equal to the sum of the weight of the sliding rod 43 and the weight 44, but the sum of the weight of the sliding rod 43 and the friction between the sleeve 42 and the sliding rod 43. In addition, since the magnitude of the friction force is not always fixed and may change during the pressing process, the friction force may be converted into a calibration error if the calibration is performed by the sum of the gravity of the slide rod 43 and the gravity of the weight 44.

Thus, as shown in FIG. 10, a force sensor 47 may be added between the slide bar 43 and the soft silicone block 46, and the reading of the force sensor 47 used as a calibration value for the pressure. This method eliminates the effect of friction between the sleeve 42 and the slider 43, resulting in a force actually applied to the pressure button 45.

In the description above, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims (16)

1. A pressure detection module, comprising: a pressure sensor and a circuit board;

the pressure sensor comprises a substrate, a first bonding pad and a sensing unit, wherein the first bonding pad and the sensing unit are arranged on the substrate; the sensing unit is used for sensing pressure and converting the pressure into an electric signal;

a second bonding pad is arranged on the circuit board, and a soldering tin through hole penetrating through the thickness direction of the circuit board is arranged on the second bonding pad;

the second bonding pad is welded with the first bonding pad;

and a preset interval for dispensing is arranged between the first bonding pad and the edge of the substrate.

2. The pressure detection module of claim 1, wherein a plurality of second pads are disposed on the circuit board, and each of the second pads has a solder via; the substrate is provided with a plurality of first bonding pads, and each first bonding pad is welded with one second bonding pad.

3. The pressure detection module of claim 1, wherein the first pad is rectangular;

the length of the first bonding pad is greater than or equal to 0.2mm, and the width of the first bonding pad is greater than or equal to 0.2 mm.

4. The pressure detection module of claim 1, wherein the first pads are arranged in a matrix on the substrate, and a distance between two adjacent first pads is greater than or equal to 0.2 mm.

5. The pressure detection module of claim 1, wherein the substrate is rectangular;

the induction unit comprises a first induction column and a second induction column which are arranged at intervals along the length direction of the substrate, and a welding area is formed between the first induction column and the second induction column; the first bonding pad is located within the bonding area.

6. The pressure detection module of claim 5, wherein the substrate has at least four first pads disposed thereon, two rows of the first pads are disposed at intervals along a width direction of the substrate, and each row of the first pads comprises two first pads disposed at intervals along a length direction of the substrate;

the preset interval is arranged between one row of the first bonding pads and the edge of the substrate close to the first bonding pads.

7. The pressure detection module of claim 6, wherein the predetermined spacing is greater than or equal to 0.25 mm.

8. The pressure detection module of claim 6, wherein the first sensing array comprises a first strain grid and a second strain grid arranged at intervals; the second induction column comprises a third strain gate and a fourth strain gate which are arranged at intervals;

the first strain gate, the second strain gate, the third strain gate and the fourth strain gate form a full-bridge series circuit;

the first pad is arranged on a series line between the first strain gate and the third strain gate, the first pad is arranged on a series line between the third strain gate and the second strain gate, the first pad is arranged on a series line between the second strain gate and the fourth strain gate, and the first pad is arranged on a series line between the fourth strain gate and the first strain gate.

9. The pressure sensing module of claim 8, wherein the first, second, third, or fourth strain gates have a resistance variation of less than or equal to 10%.

10. The pressure detection module according to any one of claims 1 to 9, wherein the circuit board is provided with at least three positioning notches, and the at least three positioning notches are arranged in a triangular shape;

at least three positioning marks are arranged on the substrate, and each positioning mark is opposite to one positioning notch.

11. The pressure detection module as claimed in claim 10, wherein the circuit board has four positioning notches arranged in a matrix;

the base plate is provided with four positioning marks which are arranged in a matrix.

12. The pressure sensing module of any of claims 1-9, further comprising a cantilever beam having a strain region and a force region;

one surface of the substrate, which is far away from the circuit board, is attached to the strain area.

13. The pressure detection module of claim 12, wherein the thickness of the cantilever beam is 0.2-2 mm.

14. The pressure sensing module of claim 13, wherein the thickness of the cantilevered beam panel is 0.5 mm.

15. The pressure sensing module of claim 12, wherein the thickness deviation of the cantilevered beam panel is ± 25 μ ι η.

16. An electronic device, comprising a main control chip and the pressure detection module of any one of claims 1-15;

the main control chip is electrically connected with the circuit board of the pressure detection module.

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