MEMS pressure sensor

Abstract

The utility model provides an MEMS pressure sensor, the interior of a first housing is provided with an accommodation cavity, the first housing is provided with an induction channel, the induction channel is communicated with the accommodation cavity, and the side wall of the induction channel is provided with a first thread; the front end of the core body is provided with an MEMS chip, the side wall of the core body is provided with a second thread, the first thread is matched with the second thread, the core body is partially screwed in the induction channel, the circuit unit is arranged in the containing cavity and electrically connected with the MEMS chip, the second shell is fixedly connected with the first shell, and a signal output mechanism is arranged in the second shell. The signal output mechanism is electrically connected with the circuit unit. According to the utility model, the first thread is arranged on the inner wall of the induction channel, the second thread matched with the first thread is arranged on the side wall of the core body, and the core body is partially screwed in the induction channel, so that on one hand, the core body can be fixed on the first shell; on the other hand, the core body and the induction channel can be sealed through the cooperation of the first thread and the second thread.

Description

Technical Field

[0001] The utility model belongs to the technical field of sensors, and more specifically, relates to a MEMS pressure sensor. Background Art

[0002] Throughout their lifecycle, vehicles experience a variety of harsh environments, including high and low temperatures, collisions, and humidity. These conditions place significant strain on the reliability of MEMS (micro-electromechanical system) pressure sensors. Traditional ceramic capacitor sensors often fail or misjudge when operating in wide temperature ranges and humid environments. Pressure sensors typically use O-ring seals, which are incompatible with a variety of pressure media. Long-term operation in certain media (such as refrigerants) carries the risk of failure and leakage, and the packaging is bulky. Utility Model Content

[0003] The purpose of the utility model is to provide a MEMS pressure sensor to improve the applicability of the pressure sensor.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a MEMS pressure sensor, including a first shell, a core, a circuit unit and a second shell, wherein a accommodating cavity is provided inside the first shell, a sensing channel connected to the outside is provided on the first shell, the sensing channel is connected to the accommodating cavity, and a first thread is provided on the side wall of the sensing channel; a MEMS chip is provided at the front end of the core, a second thread is provided on the side wall of the core, the first thread is adapted to the second thread, a part of the core is screwed into the sensing channel, and the MEMS chip is used to detect the pressure in the sensing channel; a circuit unit is provided in the accommodating cavity, the circuit unit is electrically connected to the MEMS chip, and the circuit unit is used to convert the pressure signal detected by the MEMS chip into an electrical signal; the second shell is fixedly connected to the first shell, and a signal output mechanism is provided in the second shell, and the signal output mechanism is electrically connected to the circuit unit.

[0005] In a possible implementation, the first thread and the second thread are fine threads.

[0006] In a possible implementation, a transmission circuit is provided in the core, and an input end and an output end of the transmission circuit are respectively provided at two ends of the core, the MEMS chip is electrically connected to the input end, and the output end is electrically connected to the circuit unit.

[0007] In a possible implementation, a plurality of solder balls are provided at the bottom of the MEMS chip, the solder balls are connected to the input end, and an underfill is filled between the bottom of the MEMS chip and the core.

[0008] In a possible implementation, a dam glue is provided along the circumference of the MEMS chip.

[0009] In one possible implementation, the circuit unit includes a mounting disk, a plurality of conversion elements and a conductive pad, the conductive pad is embedded in the mounting disk, the conversion element is arranged at one end of the mounting disk, the conversion element is electrically connected to the conductive pad to form a conversion circuit, the conductive pad is connected to the output end of the transmission circuit, and the conductive pad is electrically connected to the signal output mechanism.

[0010] In one possible implementation, the output end of the transmission circuit includes a plurality of elastic metal terminals, one end of the mounting plate is provided with a plurality of connection holes, the elastic metal terminals correspond one-to-one to the connection holes, and the elastic metal terminals are connected to the conductive pads through the connection holes.

[0011] In a possible implementation, the mounting plate is provided with a plurality of through holes, and the input end of the signal output mechanism is provided with a plurality of input rods, the input rods correspond to the through holes one by one, and the input rods are inserted into the corresponding through holes.

[0012] In a possible implementation, a buckle is provided at the top end of the input rod, the buckle extends radially along the second shell, and an inner side wall of the buckle abuts against the conductive pad.

[0013] In a possible implementation, the second shell is made of plastic, a metal ring is injection-molded on the second shell, and the metal ring is fixed to the first shell by welding.

[0014] The beneficial effect of the MEMS pressure sensor provided by the present invention is that: compared with the existing technology, the present invention provides a first thread on the inner wall of the sensing channel, provides a second thread compatible with the first thread on the side wall of the core body, and screws a part of the core body into the sensing channel. On the one hand, the core body can be fixed to the first shell, and on the other hand, the cooperation of the first thread and the second thread can also make the core body and the sensing channel sealed. At the same time, compared with the use of O-rings for sealing in the existing technology, the materials of the first shell and the core body are more difficult to corrode, which effectively prevents external substances from leaking into the interior of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0016] Figure 1 A schematic diagram of the structure of a MEMS pressure sensor provided in an embodiment of the present utility model;

[0017] Figure 2 A schematic structural diagram of a first housing provided in an embodiment of the present utility model;

[0018] Figure 3 A schematic structural diagram of a core body provided by an embodiment of the present invention at one angle;

[0019] Figure 4 A schematic structural diagram of the core body provided by an embodiment of the present invention from another angle;

[0020] Figure 5 A schematic structural diagram of a circuit unit provided by an embodiment of the present utility model from one angle;

[0021] Figure 6 A schematic structural diagram of a circuit unit provided by an embodiment of the present utility model from another angle;

[0022] Figure 7 A schematic structural diagram of a second housing provided by an embodiment of the present utility model at one angle;

[0023] Figure 8 This is a structural schematic diagram of the second shell provided by an embodiment of the present utility model from another angle.

[0024] Among them, the reference numerals in the figures are as follows:

[0025] 1. First housing; 2. Core; 3. Circuit unit; 4. Second housing;

[0026] 101. Accommodating cavity; 102. First thread;

[0027] 201, MEMS chip; 202, second thread; 203, underfill glue; 204, cofferdam glue; 205, elastic metal terminal;

[0028] 301, mounting pad; 302, conversion element; 303, conductive pad; 304, through hole;

[0029] 401. Signal output mechanism; 402. Input rod; 403. Buckle; 404. Metal ring. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] It should be further explained that the drawings and implementation methods of the present invention mainly describe the concept of the present invention. On the basis of this concept, some connection relationships, positional relationships, power mechanisms, power supply systems, hydraulic systems and control systems, etc. The specific forms and settings may not be fully described. However, on the premise that those skilled in the art understand the concept of the present invention, those skilled in the art can implement the above-mentioned specific forms and settings in a familiar manner.

[0032] When an element is referred to as being “fixed to” or “disposed on” another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it can be directly connected to the other element or indirectly connected to the other element.

[0033] The directions or positional relationships indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0034] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, and "several" means one or more, unless otherwise specifically defined.

[0035] The MEMS pressure sensor provided by the present utility model is now described.

[0036] Please also refer to Figure 1 and Figure 2The MEMS pressure sensor includes a first shell 1, a core 2, a circuit unit 3 and a second shell 4, wherein the interior of the first shell 1 is provided with a accommodating cavity 101, the first shell 1 is provided with a sensing channel connected to the outside, the sensing channel is connected to the accommodating cavity 101, and the side wall of the sensing channel is provided with a first thread 102; a MEMS chip 201 is provided at the front end of the core 2, and a second thread 202 is provided on the side wall of the core 2, the first thread 102 is adapted to the second thread 202, a part of the core 2 is screwed into the sensing channel, and the MEMS chip 201 is used to detect the pressure in the sensing channel; the circuit unit 3 is provided in the accommodating cavity 101, the circuit unit 3 is electrically connected to the MEMS chip 201, and the circuit unit 3 is used to convert the pressure signal detected by the MEMS chip 201 into an electrical signal; the second shell 4 is fixedly connected to the first shell, and a signal output mechanism 401 is provided in the second shell 4, and the signal output mechanism 401 is electrically connected to the circuit unit 3.

[0037] The beneficial effect of the MEMS pressure sensor provided by this embodiment is: compared with the existing technology, the MEMS pressure sensor provided by this embodiment provides a first thread 102 on the inner wall of the sensing channel, provides a second thread 202 compatible with the first thread 102 on the side wall of the core 2, and screws a part of the core 2 into the sensing channel. On the one hand, the core 2 can be fixed on the first shell 1, and on the other hand, the cooperation of the first thread 102 and the second thread 202 can also make the core 2 and the sensing channel sealed. At the same time, compared with the use of O-rings for sealing in the existing technology, the materials of the first shell 1 and the core 2 are more difficult to be corroded, which effectively prevents external substances from leaking into the interior of the sensor.

[0038] The core 2 is made of ceramic material, and a low-cost MEMS pressure chip and ceramic core 2 are used to package the pressure chip. The process is simple and significantly reduces costs compared to traditional pin welding. The material properties of the ceramic core 2 and the MEMS pressure chip are similar, and the application temperature range is wide. It can greatly reduce the internal stress of the sensor, ensure the accurate transmission of the measured pressure, and improve the accuracy of the sensor.

[0039] As a preferred technical solution, Figure 2 、 Figure 3 and Figure 4 As shown, the first thread 102 and the second thread 202 are fine threads. This arrangement allows the core 2 to have a larger contact area with the inner wall of the sensing channel after the core 2 is partially screwed into the sensing channel, which is more sealed and prevents substances outside the first shell 1 from entering the first shell 1.

[0040] In this embodiment, a transmission circuit is provided within the core 2. The input and output terminals of the transmission circuit are located at opposite ends of the core 2. The MEMS chip 201 is electrically connected to the input terminal, and the output terminal is electrically connected to the circuit unit 3. The transmission circuit configuration enables signals from the MEMS chip 201 to be transmitted to the circuit unit 3.

[0041] like Figure 4 As shown, the bottom of the MEMS chip 201 is provided with multiple solder balls, which are connected to the input terminals. An underfill 203 is filled between the bottom of the MEMS chip 201 and the core 2. Furthermore, a cofferdam 204 is provided along the circumference of the MEMS chip 201. In this embodiment, the cofferdam 204 and underfill 203, which are resistant to high and low temperatures and dielectrics, are used to protect the MEMS flip-chip, isolate it from stress and corrosive media, and provide support for the chip.

[0042] like Figure 5 and Figure 6 As shown, the circuit unit 3 includes a mounting disk 301, multiple conversion elements 302 and a conductive pad 303. The conductive pad 303 is embedded in the mounting disk 301, and the conversion element 302 is arranged at one end of the mounting disk 301. The conversion element 302 is electrically connected to the conductive pad 303 to form a conversion circuit. The conductive pad 303 is connected to the output end of the transmission circuit, and the conductive pad 303 is electrically connected to the signal output mechanism 401.

[0043] like Figure 3 As shown, the output end of the transmission circuit includes multiple elastic metal terminals 205. One end of the mounting plate 301 is provided with multiple connection holes. The elastic metal terminals 205 correspond one-to-one with the connection holes, and the elastic metal terminals 205 are connected to the conductive pads 303 through the connection holes. The provision of the elastic metal terminals 205 ensures that after the circuit unit 3 is installed, the chip, transmission circuit, and conversion circuit are connected to form a single circuit, facilitating the conversion of the detected pressure signal into an electrical signal. The use of elastic crimping for interconnection of the electrical signals simplifies the manufacturing process and reduces the cost compared to traditional pin or spring leaf solutions.

[0044] like Figure 6 and Figure 7 As shown, a plurality of through-holes 304 are provided on the mounting plate 301, and a plurality of input rods 402 are provided at the input end of the signal output mechanism 401. The input rods 402 correspond one-to-one with the through-holes 304 and are inserted into the corresponding through-holes 304. The arrangement of the input rods 402 and through-holes 304 enables the signal output mechanism 401 to be connected to the circuit formed by the aforementioned chip, transmission circuit, and conversion circuit, facilitating signal output.

[0045] Preferably, a clip 403 is provided at the top of the input rod 402. The clip 403 extends radially along the second housing 4, and the inner sidewall of the clip 403 abuts against the conductive pad 303. Using the clip 403 connection method to secure and electrically interconnect the circuit unit 3 and the signal output mechanism 401 simplifies the assembly process and reduces costs compared to traditional pin soldering solutions.

[0046] In this embodiment, Figure 8 The signal output mechanism 401 shown is provided with a plurality of output holes. Meanwhile, power supply terminals are also provided in the output holes, so that the entire MEMS pressure sensor can be powered through the output holes.

[0047] Finally, the second shell 4 is made of plastic, and a metal ring 404 is injection molded on the second shell 4. The first shell 1 is made of metal material, and the metal ring 404 is welded and fixed to the first shell 1. The fixation of the metal ring 404 facilitates the sealing and fixation of the second shell 4 and the first shell 1.

[0048] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A MEMS pressure sensor, characterized in that: include: A first shell (1) is provided with a receiving cavity (101) therein, a sensing channel communicating with the outside is provided on the first shell (1), the sensing channel is communicated with the receiving cavity (101), and a first thread (102) is provided on a side wall of the sensing channel; A core (2) is provided with a MEMS chip (201) at its front end, a second thread (202) is provided on a side wall of the core (2), the first thread (102) and the second thread (202) are adapted to each other, a portion of the core (2) is screwed into the sensing channel, and the MEMS chip (201) is used to detect pressure in the sensing channel; A circuit unit (3) is provided in the accommodating cavity (101), the circuit unit (3) is electrically connected to the MEMS chip (201), and the circuit unit (3) is used to convert a pressure signal detected by the MEMS chip (201) into an electrical signal; The second shell (4) is fixedly connected to the first shell, and a signal output mechanism (401) is provided in the second shell (4), and the signal output mechanism (401) is electrically connected to the circuit unit (3).

2. The MEMS pressure sensor according to claim 1, wherein: The first thread (102) and the second thread (202) are fine threads.

3. The MEMS pressure sensor according to claim 2, wherein: A transmission circuit is provided in the core (2), the input end and the output end of the transmission circuit are respectively provided at two ends of the core (2), the MEMS chip (201) is electrically connected to the input end, and the output end is electrically connected to the circuit unit (3).

4. The MEMS pressure sensor according to claim 3, wherein: A plurality of tin solder balls are provided at the bottom of the MEMS chip (201), the tin solder balls are connected to the input end, and a bottom filler (203) is filled between the bottom of the MEMS chip (201) and the core (2).

5. The MEMS pressure sensor according to claim 4, wherein: A cofferdam glue (204) is provided along the circumference of the MEMS chip (201).

6. The MEMS pressure sensor according to claim 5, wherein: The circuit unit (3) comprises a mounting plate (301), a plurality of conversion elements (302) and a conductive pad (303), wherein the conductive pad (303) is embedded in the mounting plate (301), the conversion element (302) is arranged at one end of the mounting plate (301), the conversion element (302) and the conductive pad (303) are electrically connected to form a conversion circuit, the conductive pad (303) is connected to the output end of the transmission circuit, and the conductive pad (303) is electrically connected to the signal output mechanism (401).

7. The MEMS pressure sensor according to claim 6, wherein: The output end of the transmission circuit includes a plurality of elastic metal terminals (205), one end of the mounting plate (301) is provided with a plurality of connection holes, the elastic metal terminals (205) correspond one-to-one to the connection holes, and the elastic metal terminals (205) are connected to the conductive pad (303) through the connection holes.

8. The MEMS pressure sensor according to claim 7, wherein: The mounting plate (301) is provided with a plurality of through holes (304), and the input end of the signal output mechanism (401) is provided with a plurality of input rods (402), the input rods (402) corresponding to the through holes (304) one by one, and the input rods (402) are inserted into the corresponding through holes (304).

9. The MEMS pressure sensor according to claim 8, wherein: A buckle (403) is provided at the top end of the input rod (402), the buckle (403) extends radially along the second shell (4), and the inner side wall of the buckle (403) abuts against the conductive pad (303).

10. The MEMS pressure sensor according to claim 9, wherein: The second shell (4) is made of plastic, and a metal ring (404) is injection-molded on the second shell (4), and the metal ring (404) is welded and fixed to the first shell (1).

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