CN212513174U

CN212513174U - Gas flow sensor based on MEMS hot wire type technology

Info

Publication number: CN212513174U
Application number: CN202021380139.0U
Authority: CN
Inventors: 胡华才; 李良
Original assignee: Heyuan Xingtong Time Frequency Electronic Co ltd
Current assignee: Heyuan Xingtong Time Frequency Electronic Co ltd
Priority date: 2020-07-14
Filing date: 2020-07-14
Publication date: 2021-02-09
Anticipated expiration: 2030-07-14

Abstract

The utility model discloses a gas flow sensor based on MEMS hot-wire type technique, including base, shell and MEMS hot-wire type air current sensor chip, MEMS hot-wire type air current sensor chip is fixed on the base, the shell sets up equally on the base, just the shell covers MEMS hot-wire type air current sensor chip, MEMS hot-wire type air current sensor chip pass through the gold thread with the pin nation of base, be provided with two convection holes on the shell and be convenient for the air current to flow through the surface of MEMS hot-wire type air current sensor chip. The utility model discloses owing to adopted MEMS hot-wire type gas flow sensor, possess characteristics such as small, the energy consumption is low, the response is fast, utilize the tangent design in convection current hole passageway and chip surface, can reduce the influence that the return air disturbed and reduce the chip and hinder to airflow channel to realized small-size encapsulation when guaranteeing the high performance.

Description

Gas flow sensor based on MEMS hot wire type technology

Technical Field

The utility model relates to a flow sensor especially involves a gas flow sensor based on MEMS hot wire formula technique.

Background

The gas flow sensor is a sensor device capable of detecting the magnitude of a gas flow. The device can detect the signal of the size of the gas flow and convert the signal into an electric signal, and the circuit achieves the purpose of identifying the size of the gas flow by identifying the electric signal. The gas sensor can be implemented in various ways, such as a propeller type, a float type, an ultrasonic type, a hot wire type, and the like. The gas flow sensor is widely applied to occasions such as gas blockage detection, combustion control, pipeline air volume control and the like. With the development of electronic technologies such as artificial intelligence and the internet of things, the demand of components of sensors is rapidly increased, and especially, the gas sensor with small package, low power consumption and high sensitivity is most popular. Therefore, how to realize a small-sized package for the gas flow sensor chip is a difficult problem for those skilled in the art.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a little, the gas flow sensor that the performance is high of packaging structure based on MEMS hot-wire type technique.

The utility model provides a gas flow sensor based on MEMS hot-wire type technique, including base, shell and MEMS hot-wire type air current sensor chip, MEMS hot-wire type air current sensor chip is fixed on the base, the shell sets up equally on the base, just the shell covers MEMS hot-wire type air current sensor chip, MEMS hot-wire type air current sensor chip pass through the gold thread with the pin nation of base, it flows to be provided with two convection holes air current of being convenient for on the shell the surface of MEMS hot-wire type air current sensor chip, the convection hole is in horizontal position on the shell with the surface of MEMS hot-wire type air current sensor chip is tangent.

As a further aspect of the present invention: the MEMS hot-wire type airflow sensor chip is fixed on the base through a die bonding technology.

As a further aspect of the present invention: one end of the gold wire is welded on a functional pin of the MEMS hot-wire type airflow sensor chip, and the other end of the gold wire is welded on a bonding pad of the base, so that the functional pin and the bonding pad are conducted.

As a further aspect of the present invention: the convection hole comprises a first convection hole and a second convection hole, and the first convection hole and the second convection hole are oppositely arranged on the shell.

As a further aspect of the present invention: the shell is flat and cubic, the first convection hole is formed in the side face of the shell, and the second convection hole is formed in the side face, opposite to the first convection hole, of the shell.

As a further aspect of the present invention: the first convection hole is identical in size and shape to the second convection hole.

As a further aspect of the present invention: the first convection hole is larger or smaller than the second convection hole.

The technical effects of the utility model: the utility model discloses owing to adopted MEMS hot-wire type gas flow sensor, possess characteristics such as small, the energy consumption is low, the response is fast, utilize the tangent design in convection current hole passageway and chip surface, can reduce the influence that the return air disturbed and reduce the chip and hinder to airflow channel to realized small-size encapsulation when guaranteeing the high performance.

Drawings

Fig. 1 is a schematic structural diagram of a gas flow sensor provided by the present invention.

Reference numerals: 100. a housing; 110. a first convection hole; 120. a second convection hole; 200. a base; 300. a MEMS hot-wire airflow sensor chip; 400. and (4) gold wires.

The objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, a gas flow sensor based on MEMS hot-wire type technology, including base 200, shell 100 and MEMS hot-wire type airflow sensor chip 300, MEMS hot-wire type airflow sensor chip 300 is fixed on base 200, shell 100 sets up equally on base 200, just shell 100 covers MEMS hot-wire type airflow sensor chip 300, MEMS hot-wire type airflow sensor chip 300 through gold wire 400 with base 200's pin nation, be provided with two convection holes on shell 100 and be convenient for the air current to flow through MEMS hot-wire type airflow sensor chip 300's surface, the convection hole is in horizontal position on shell 100 with MEMS hot-wire type airflow sensor chip 300's surface is tangent. The hot-wire flowmeter adopts a thermal diffusion principle, and the thermal diffusion technology is a technology with excellent performance and high reliability under severe conditions. Thermal flow meters have two temperature sensors placed in the media, one of which is heated to a temperature above ambient temperature and the other of which is used to sense the media temperature. The flow rate of the medium is increased, the heat quantity taken away by the medium is increased, the temperature difference of the two temperature sensors changes along with the change of the flow rate of the medium, and the flow Q of the fluid can be obtained according to the proportional relation between the temperature difference and the flow rate of the medium. The utility model discloses owing to adopted MEMS hot-wire type gas flow sensor, possess characteristics such as small, the energy consumption is low, the response is fast, utilize the convection current hole to reduce the influence that the return air disturbed and reduce the chip and obstruct to airflow channel to realized small-size encapsulation when guaranteeing the high performance.

Further, the MEMS hot-wire type airflow sensor chip 300 is fixed on the base 200 by a die bonding technique. Die attach technology is generally used for the fixed of LED chip, specifically is some glue (conducting resin or insulating cement) and adds and toasts, makes the chip be fixed in on the support the utility model discloses in, MEMS hot wire type air current sensor chip 300 also fixes on base 200 through this mode. The base 200 is made of ceramic, or may be made of other common materials such as PCB, and is not limited herein.

Furthermore, one end of the gold wire 400 is soldered to a functional pin of the MEMS hot-wire airflow sensor chip 300, and the other end is soldered to a pad of the base 200, so that the functional pin and the pad are electrically connected. The term bonding is derived from bonding and is interpreted as "chip bonding" or "bonding". Bonding is a wire bonding method in the chip production process, generally used for connecting the internal circuit of the chip with the package pin or the gold-plated copper foil of the circuit board by a gold wire or an aluminum wire before packaging, ultrasonic waves (generally 40-140KHz) from an ultrasonic generator generate high-frequency vibration through a transducer, the high-frequency vibration is transmitted to a chopper through an amplitude transformer, when the chopper is contacted with a lead and a welded piece, under the action of pressure and vibration, the surfaces of the to-be-welded metals are mutually rubbed, an oxide film is damaged, and plastic deformation occurs, so that two pure metal surfaces are tightly contacted, the combination of atomic distance is achieved, and finally, firm mechanical connection is formed.

Further, the convection holes include a first convection hole 110 and a second convection hole 120, and the first convection hole 110 and the second convection hole 120 are oppositely disposed on the housing 100.

Further, the housing 100 has a flat cubic shape, the first convection hole 110 is provided on a side surface of the housing 100, and the second convection hole 120 is provided on an opposite side surface of the first convection hole 110. It will be appreciated that the air flow into the housing 100 through the first convection hole 110 or the second convection hole 120 and out of the second convection hole 120 or the first convection hole 110 is provided to reduce the interference of return air in the housing 100, enabling the chip to secure high sensitivity.

Further, the first convection hole 110 is identical in size and shape to the second convection hole 120.

Further, the first convection hole 110 is larger or smaller than the second convection hole 120.

The utility model discloses when using, the selection is installed with the tangent direction of pipeline, and the direction of guaranteeing first convection hole 110 and second convection hole 120 simultaneously is corresponding with the flow direction of air current in the pipeline, has guaranteed that the air current flows through smooth and easy on MEMS hot wire air flow sensor chip 300's surface, also reduces the hindrance that the sensor flowed to the air current in the pipeline simultaneously.

The above only is the preferred embodiment of the present invention, not limiting the scope of the present invention, all the equivalent structures or equivalent flow changes made by the contents of the specification and the drawings, or directly or indirectly applied to other related technical fields, are included in the same way in the protection scope of the present invention.

Claims

1. A gas flow sensor based on MEMS hot wire technology is characterized in that: including base (200), shell (100) and MEMS hot-wire type airflow sensor chip (300), MEMS hot-wire type airflow sensor chip (300) are fixed on base (200), shell (100) set up equally on base (200), just shell (100) cover MEMS hot-wire type airflow sensor chip (300), MEMS hot-wire type airflow sensor chip (300) through gold wire (400) with the pin nation of base (200), it is convenient for the air current to flow through to be provided with two convection holes on shell (100) the surface of MEMS hot-wire type airflow sensor chip (300), the convection hole is in horizontal position on shell (100) with the surface of MEMS hot-wire type airflow sensor chip (300) is tangent.

2. The gas flow sensor of claim 1, wherein: the MEMS hot-wire type airflow sensor chip (300) is fixed on the base (200) through a die bonding technology.

3. The gas flow sensor of claim 1, wherein: one end of the gold wire (400) is welded on a functional pin of the MEMS hot-wire type airflow sensor chip (300), and the other end of the gold wire is welded on a bonding pad of the base (200), so that the functional pin and the bonding pad are conducted.

4. The gas flow sensor of claim 1, wherein: the convection hole comprises a first convection hole (110) and a second convection hole (120), and the first convection hole (110) and the second convection hole (120) are oppositely arranged on the housing (100).

5. The gas flow sensor according to claim 4, wherein: the housing (100) is in the shape of a flat cube, the first convection hole (110) is provided on a side surface of the housing (100), and the second convection hole (120) is provided on an opposite side surface of the first convection hole (110).

6. The gas flow sensor according to claim 4, wherein: the first convection hole (110) is identical in size and shape to the second convection hole (120).

7. The gas flow sensor according to claim 4, wherein: the first convection hole (110) is larger or smaller than the second convection hole (120).