CN105928655B

CN105928655B - Differential pressure sensor and manufacturing method thereof

Info

Publication number: CN105928655B
Application number: CN201610235323.8A
Authority: CN
Inventors: 孙拓夫; 冯明; 郑云; 朱宗恒; 侯勇
Original assignee: Wuhu Causes Electronics Co Ltd That Is Open To Traffic
Current assignee: Wuhu causes the Electronics Co., Ltd. that is open to the traffic
Priority date: 2016-04-15
Filing date: 2016-04-15
Publication date: 2020-02-21
Anticipated expiration: 2036-04-15
Also published as: CN105928655A

Abstract

The invention discloses a differential pressure sensor and a manufacturing method thereof, comprising the following steps: the shell (5), the shell (5) is provided with a counter bore (51); the circuit board (4) is arranged in the counter bore (51), and a through hole (41) is formed in the circuit board (4); the chip (1) is arranged on the upper part of the circuit board (4), the back surface of the chip (1) faces the circuit board (4), and the pressure sensing through hole (11) of the chip (1) is opposite to the through hole (41); the drainage channel (52) arranged at the bottom of the counter bore (51) directly isolates the contact of the via hole (11) and dust, and the phenomena of hole blockage and water accumulation can not occur.

Description

Differential pressure sensor and manufacturing method thereof

Technical Field

The invention belongs to the technical field of sensors, and particularly relates to a differential pressure sensor and a manufacturing method thereof.

Background

In the process of implementing the invention, the inventor finds that the prior art has at least the following problems:

when the differential pressure sensor works and is in the environment of dust and water accumulation, the dust accumulation is used for a long time to lead the sensor to be easy to block holes, the sealing performance is poor, the pressure sensing capacity of the sensor is poor after long-term test, the water accumulation of the sensor is long-term, the sensor is in a humid environment, the error of a product is large, the water accumulation can be frozen under the condition that the temperature is lower than 0 ℃ in winter, and the function of the product can be directly failed.

Disclosure of Invention

The invention aims to solve the technical problem of providing a differential pressure sensor which directly isolates a via hole from being contacted with dust and does not cause the phenomena of hole blockage and water accumulation and a manufacturing method thereof.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a differential pressure sensor, having:

the shell is provided with a counter bore;

the circuit board is arranged in the counter bore, and a through hole is formed in the circuit board;

the chip is arranged on the upper part of the circuit board, the back surface of the chip faces the circuit board, and the pressure sensing through hole of the chip is opposite to the through hole;

and the drainage channel is arranged at the bottom of the counter bore.

The chip is bonded on the circuit board and also comprises a restraint ring which is bonded on the circuit board and used for limiting the chip.

The chip packaging structure further comprises silica gel which is encapsulated in the restraint ring and protects the surface of the chip.

The upper end face of the counter bore is lower than the upper end face of the chip.

The circuit board is bonded in the counter bore, and the bonding surface of the counter bore is provided with dermatoglyph.

The drain outlet face of the drain channel is lower than the chip height.

The manufacturing method of the differential pressure sensor comprises the following steps:

a) sequentially adhering the chip and the constraint ring to a circuit board to form a module, and encapsulating the silica gel into the constraint ring to protect the surface of the chip;

b) the module adopts a backpressure chip scheme, and the via hole on the back of the module is placed in a working environment;

c) the structure of the shell is provided with a counter bore, the upper end face of the counter bore is lower than the upper end face of the chip, and the sensor actively drains water through a drainage channel of the shell.

One of the technical scheme has the following advantages or beneficial effects that the through hole is directly isolated from dust contact, the phenomenon of hole blocking cannot occur, meanwhile, the position of the shell drainage channel is lower than the height of the chip, water flows out of the drainage channel before reaching the height of the chip, and the phenomenon of water accumulation does not exist.

Drawings

Fig. 1 is a schematic structural view of a differential pressure sensor provided in an embodiment of the present invention;

FIG. 2 is a cross-sectional view A-A of FIG. 1;

FIG. 3 is a cross-sectional view B-B of FIG. 1;

the labels in the above figures are: 1. the device comprises a chip, 11, a via hole, 2, silica gel, 3, a restraint ring, 4, a circuit board, 41, a through hole, 5, a shell, 51, a counter bore, 52 and a drainage channel.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Example one

Referring to fig. 1, a differential pressure sensor has:

a housing 5, wherein a counter bore 51 is arranged on the housing 5;

the circuit board 4 is arranged in the counter bore 51, and a through hole 41 is arranged on the circuit board 4;

the chip 1 is arranged on the upper part of the circuit board 4, the back surface of the chip 1 faces the circuit board 4, and the pressure sensing through hole 11 of the chip 1 is opposite to the through hole 41;

a drain passage 52 provided at the bottom of the counterbore 51.

The chip 1 is bonded on the circuit board 4, and also comprises a restraint ring 3 bonded on the circuit board 4 and used for limiting the chip 1.

The chip packaging structure further comprises silica gel 2 which is encapsulated in the restraint ring 3 and protects the surface of the chip 1.

The upper end surface of the counterbore 51 is lower than the upper end surface of the chip 1.

The circuit board 4 is bonded in the counterbore 51, and the bonding surface of the counterbore 51 is provided with dermatoglyph. The back of the module is adhered to the shell 5, and the adhering surface of the shell 5 is subjected to dermatoglyph treatment, so that the adhesion force is enhanced, and a good sealing effect is achieved.

The drain outlet face of the drain channel 52 is lower than the height of the chip 1.

Chip 1 is model DS 12887.

As shown in fig. 2, the chip 1 is bonded to the ceramic circuit board 4, and the back of the chip 1 faces downward, so that the pressure sensed by the chip 1 is directly sensed from the through hole 41 of the ceramic circuit board 4, the via hole 11 of the chip 1 is prevented from being blocked by dust, the ceramic circuit board 4 is bonded to the shell 5, and the bonding surface of the shell 5 is subjected to dermatoglyph treatment, so that the friction force is enhanced, and the sealing performance between the ceramic circuit board 4 and the shell 5 is more stable;

meanwhile, as shown in fig. 3, the sensor housing 5 is provided with a drainage channel 52, and it can be seen from fig. 3 that the drainage outlet surface is lower than the height of the chip 1, so that the water level can be effectively drained actively when the height of the chip 1 is not reached, the chip 1 is effectively protected, and the sensor has a waterproof function.

Example two

a) sequentially adhering the chip 1 and the constraint ring 3 to the circuit board 4 to form a module, and encapsulating the silica gel 2 into the constraint ring 3 to protect the surface of the chip 1 and prevent the surface of the chip 1 from being influenced by dust;

b) the module adopts the scheme of the backpressure chip 1, and the through hole 11 on the back of the module is placed in a working environment and cannot be contacted with dust;

c) the design of counter bore 51 is arranged in the structure of the shell 5, the surface of the counter bore 51 is lower than the height of the chip 1, the principle that water flows from the high position to the low position and the principle of a communicating vessel are combined, the sensor actively drains water through the drainage channel 52 of the shell 5 in the environment that the sensor is in accumulated water, and the waterproof performance of the sensor is completely met.

One of the above technical solutions has the following advantages or beneficial effects that the contact between the via hole 11 and dust is directly isolated, the hole blocking phenomenon cannot occur, and meanwhile, the position of the drainage channel 52 of the shell 5 is lower than the height of the chip 1, so that water flows out from the drainage channel 52 before reaching the height of the chip 1, and the water accumulation phenomenon does not exist.

The invention has been described above with reference to the accompanying drawings, it is obvious that the invention is not limited to the specific implementation in the above-described manner, and it is within the scope of the invention to apply the inventive concept and solution to other applications without substantial modification.

Claims

1. A differential pressure sensor, having:

the device comprises a shell (5), wherein a counter bore (51) is formed in the shell (5);

the circuit board (4) is installed in the counter bore (51), and a through hole (41) is formed in the circuit board (4);

the chip (1) is mounted on the upper portion of the circuit board (4), the back face of the chip (1) faces the circuit board (4), and the pressure sensing through hole (11) of the chip (1) is opposite to the through hole (41);

a drain passage (52) provided at the bottom of the counterbore (51);

the chip (1) is bonded on the circuit board (4), and the chip packaging structure further comprises a restraint ring (3) which is bonded on the circuit board (4) and used for limiting the chip (1);

the silicon gel (2) is encapsulated in the restraint ring (3) and protects the surface of the chip (1);

it is characterized in that the preparation method is characterized in that,

the upper end surface of the counter bore (51) is lower than the upper end surface of the chip (1);

the drainage outlet surface of the drainage channel (52) is lower than the height of the chip (1), so that the water is actively drained when the water level does not reach the height of the chip (1), and the chip (1) is protected;

a) sequentially adhering the chip (1) and the confinement ring (3) to the circuit board (4) to form a module, and encapsulating the silica gel (2) into the confinement ring (3) to protect the surface of the chip (1);

b) the module adopts a backpressure chip (1) scheme, and a through hole (11) on the back of the module is placed in a working environment;

c) the structure of the shell (5) is provided with a counter bore (51), the upper end face of the counter bore (51) is lower than the upper end face of the chip (1), and the sensor actively drains water through a drainage channel (52) of the shell (5).

2. The differential pressure sensor according to claim 1, wherein the circuit board (4) is bonded within the counterbore (51), and the bonding surface of the counterbore (51) is provided with a dermatoglyph.