CN116067445A

CN116067445A - Flow sensor, flow sensor assembly and electronic equipment

Info

Publication number: CN116067445A
Application number: CN202211713884.6A
Authority: CN
Inventors: 李嗣晗; 颜培力; 安兴; 王安康; 罗英哲
Original assignee: Shanghai Sirui Technology Co ltd
Current assignee: Shanghai Sirui Technology Co ltd
Priority date: 2022-03-08
Filing date: 2022-12-29
Publication date: 2023-05-05
Also published as: CN219495335U; CN219532146U; CN114608664A

Abstract

The application provides a flow sensor, flow sensor subassembly and electronic equipment, wherein, flow sensor includes first temperature detection unit, second temperature detection unit, heating unit and sensing area, first temperature detection unit the second temperature detection unit with heating unit all corresponds to the sensing area sets up, first temperature detection unit with second temperature detection unit separates each other, just heating unit is located first temperature detection unit with between the second temperature detection unit, flow sensor still includes fluid channel, perhaps, flow sensor cooperatees with fluid channel, and fluid passes through when fluid channel's restriction flows through sensing area, heating unit controlled start-up heats. The heating unit is set to be controlled to start heating, so that the problem of high power consumption caused by long-term heating of the heating unit can be avoided.

Description

Flow sensor, flow sensor assembly and electronic equipment

Technical Field

The application relates to the technical field of sensors, in particular to a flow sensor, a flow sensor assembly and electronic equipment.

Background

With the rapid development of electronic technology, flow detection or differential pressure detection is widely used on various types of electronic devices. At present, differential pressure sensors are of two types, namely differential pressure sensors based on a pressure sensitivity principle, the technology is mature and widely applied, but the zero point stability is poor, the zero point is easy to drift, the precision and the resolution ratio are poor, and the problem of poor measurement precision exists when the differential pressure sensor is applied to ultra-low differential pressure measurement, such as measuring the differential pressure lower than 500Pa in electronic cigarettes. Another is a differential pressure sensor based on the thermal fluid flow principle, which has high measurement accuracy, but has large package size and power consumption, is inconvenient to install in small-sized electronic devices such as electronic cigarettes, and is not suitable for electronic devices requiring long-term standby.

Disclosure of Invention

In order to solve at least one technical problem, an object of the present application is to provide a flow sensor, a flow sensor assembly and an electronic device, which are beneficial to reducing power consumption and suitable for electronic devices requiring long-term standby.

In order to achieve the above object, the technical solution provided in the present application includes:

in a first aspect, a flow sensor is provided that includes a first temperature detection unit, a second temperature detection unit, a heating unit, and a sensing region. The first temperature detection unit, the second temperature detection unit and the heating unit are arranged corresponding to the sensing area, the first temperature detection unit and the second temperature detection unit are mutually spaced, and the heating unit is positioned between the first temperature detection unit and the second temperature detection unit. The flow sensor may further comprise a fluid channel or the flow sensor may be coupled to the fluid channel. Fluid flows through the sensing region under the restriction of the fluid channel as it passes through the fluid channel. The heating unit is controlled to start heating.

After controlled activation of the heating unit, the heating unit increases its ambient temperature, and as the fluid flows through the fluid passage, it absorbs heat, causing the temperature to decrease. That is, the fluid flow causes the sensing region to generate a temperature gradient, and the temperature detected by the temperature detecting unit located upstream of the fluid flow path is lower than the temperature detected by the temperature detecting unit located downstream of the fluid flow path, thereby causing the temperature difference of the temperatures detected by the two temperature detecting units to change. The temperature differential change may be converted to an electrical signal, which may further be processed to indicate one or more fluid property information, and/or to generate one or more control signals. Specifically, the one or more fluid characteristic information includes information of whether or not there is a fluid passing through the fluid passage, information of a flow direction of the fluid in the fluid passage, information of a flow rate (flow rate) of the fluid in the fluid passage, and the like. The one or more control signals include controlling the controlled module to operate or cease operating, controlling an operating voltage (operating current) of the controlled module, controlling the controlled module to display fluid characteristic information, controlling the controlled module to generate alarm information, and the like.

In the application, the heating unit is set to be controlled to start heating, so that the heating unit can start heating when the fluid characteristic needs to be detected, and can stop heating when the fluid characteristic does not need to be detected, and the problem that the power consumption is high due to the fact that the heating unit is in a heating state for a long time is avoided.

It should be noted that the fluid may refer to a gas or a liquid according to the application. The fluid channel may be a bidirectional fluid channel, that is, under the restriction of the fluid channel, when the fluid flows through the sensing area, the fluid may flow through the first temperature detecting unit, the heating unit and the second temperature detecting unit sequentially, or may flow through the second temperature detecting unit, the heating unit and the first temperature detecting unit sequentially.

The heating may be continued after the heating means is started, or may be intermittent, and is not limited thereto.

In one embodiment, the first temperature detecting unit and the second temperature detecting unit are the same or close to the same in distance from the heating unit. After the heating unit is controlled to start heating, the ambient temperature of the heating unit rises. When no fluid passes through the fluid channel, the temperatures around the heating units are symmetrically distributed, and the first temperature detection unit and the second temperature detection unit detect the same temperature, namely, the temperature difference between the temperatures detected by the first temperature detection unit and the second temperature detection unit is zero. When fluid passes through the fluid channel, heat can be absorbed, so that the temperature is reduced, that is, the temperature gradient is generated in the sensing area caused by fluid flow, the temperature detected by the temperature detection unit positioned at the upstream of the fluid flow path is lower than the temperature detected by the temperature detection unit positioned at the downstream of the fluid flow path, and the temperature difference between the temperatures detected by the two temperature detection units is not zero. That is, the fluid flow causes a change in the temperature difference of the temperatures detected by the two temperature detection units, so that a corresponding electrical signal can be generated.

In one embodiment, the flow sensor further comprises an insulating layer. The first temperature detection unit, the second temperature detection unit and the heating unit are all arranged on the insulating layer. Through all setting up first temperature detecting element, second temperature detecting element and heating element in the insulating layer for first temperature detecting element, second temperature detecting element and heating element all do not expose outward, so, are favorable to insulating water or pollutant's influence, improve first temperature detecting element, second temperature detecting element's interference killing feature to ambient temperature detection.

In one embodiment, the flow sensor is further provided with a cavity, the insulating layer being located between the fluid channel and the cavity, the cavity being in communication with the surrounding environment or the outside. That is, the first temperature detecting unit, the second temperature detecting unit, and the heating unit are located between the fluid passage and the cavity, so that heat conduction can be reduced when the heating unit heats, thereby reducing heat loss. In addition, the heating unit can expand air in the cavity below the insulating layer after heating, so that the differential pressure on the upper side and the lower side of the insulating layer is easily increased, and the fluid channels and the cavities on the upper side and the lower side of the insulating layer can be prevented from forming differential pressure due to heating by communicating the cavity with the surrounding environment or the outside.

In one embodiment, the flow sensor further comprises a substrate. An edge portion of the insulating layer is supported on the substrate. The substrate is internally provided with a cavity which penetrates through the lower surface of the substrate and is communicated with the surrounding environment or the outside.

In one embodiment, the heating unit may be manually controlled to initiate heating based on operational requirements.

In one embodiment, the heating unit may be controlled to initiate heating at a timing such that the heating unit initiates heating automatically for certain periods of time.

In one embodiment, the flow sensor further comprises a detection unit that generates an electrical signal when detecting that fluid flows through the sensing region, and the heating unit is controlled to initiate heating based on the electrical signal. It should be noted that, the detecting unit is an electronic component with lower power consumption than the heating unit, so that the operation power consumption of the detecting unit is relatively lower, and the heating unit is controlled by the detecting unit to start heating, so that the problem of higher power consumption caused by long-term heating of the heating unit is avoided.

In one embodiment, the detection unit is two opposite electrodes, one of which is an elastic electrode and the other is a fixed electrode, and the two electrodes are disposed in the sensing area. The elastic electrode deforms when the fluid flows through the sensing area, and whether the fluid flows through the sensing area can be judged by whether the capacitance between the two electrodes changes.

In one embodiment, the detection cell is a differential pressure detection cell. The differential pressure detection unit is disposed corresponding to the sensing region. The differential pressure detection unit generates an electrical signal when detecting that fluid flows through the sensing region, and the heating unit is controlled to start heating based on the electrical signal. The differential pressure detection unit is an electronic component with lower power consumption than the heating unit. The differential pressure detection unit may initially detect whether there is fluid flowing through the sensing region. When no fluid is flowing through the sensing region, the heating unit is not operated to reduce power consumption. When the fluid flows through the sensing area, the differential pressure detection unit detects that the fluid flows through the sensing area to output a target electric signal, the heating unit is controlled to start heating based on the target electric signal, and then the first temperature detection unit and the second temperature detection unit are used for detecting the fluid characteristics with high precision. In this way, the problem that the heating unit still needs to be continuously heated when no fluid flows, so that the power consumption is high can be improved, and the high-precision and low-power consumption detection of the fluid characteristics can be realized.

In one embodiment, the differential pressure detection unit is disposed in the insulating layer for sensing deformation or stress variation of the insulating layer. Whether a fluid flows through the sensing area is judged by sensing whether the insulating layer is deformed or stressed. Specifically, if no fluid flows in the fluid channel, the insulating layer will not deform or will not change stress. If fluid flow exists in the fluid channel, the pressure difference between the cavity and the fluid channel is changed, so that the insulating layer is easy to deform or generate stress change. The differential pressure detection unit can generate corresponding electric signals due to deformation or stress change of the insulating layer. Thus, whether the insulating layer is deformed or stressed can be judged based on the electric signal output by the differential pressure detection unit, so that whether the fluid flow exists in the fluid channel is judged. Further, the heating unit is controlled to start heating when fluid flows in the fluid channel, so that the heating unit can start working when needed, and the power consumption is effectively reduced.

In one embodiment, the differential pressure detection units are four in number and are symmetrically arranged on the insulating layer in pairs.

In one embodiment, the differential pressure sensing element is a piezoresistive sensing element or a piezoelectric sensing element.

In one embodiment, the piezoelectric detection unit has a ring structure and is disposed on the insulating layer.

In one embodiment, a preset correspondence between the output of the differential pressure detection unit and the output of the first temperature detection unit and the output of the second temperature detection unit are stored, whether the output of the differential pressure detection unit and the output of the first temperature detection unit and the output of the second temperature detection unit meet the preset correspondence is checked every preset time, and when the preset correspondence is not met, the sensing area is judged to be polluted.

In one embodiment, the preset corresponding relation is that the ratio of the output current of the differential pressure detection unit to the output current of the first temperature detection unit and the output current of the second temperature detection unit are within a preset range.

In one embodiment, the processor controls the heating unit to heat when the sensing area is judged to be polluted, and/or corrects the output of the first temperature detection unit and the output of the second temperature detection unit through a preset algorithm.

In one embodiment, the flow sensor includes a first silicon wafer and a second silicon wafer, the first silicon wafer and the second silicon wafer are stacked and bonded to form a body, and a gap between the first silicon wafer and the second silicon wafer forms the fluid channel. By stacking, bonding and other techniques of the two silicon wafers, a fluid channel is formed at the silicon wafer level, which is beneficial to reducing the manufacturing cost and the subsequent packaging size, so that the flow sensor has smaller finished size and is beneficial to application in small electronic equipment (such as electronic cigarettes).

In one embodiment, the bonding mode of the first silicon wafer and the second silicon wafer is any one of Si-Si bonding, si-O-Si bonding, eutectic bonding and glass paste bonding.

In one embodiment, one of the first silicon wafer and the second silicon wafer is provided with an open slot relative to the other. By providing the open groove, the gap between the first silicon wafer and the second silicon wafer can be increased, thereby increasing the radial dimension of the fluid passage, i.e., increasing the sectional area of the fluid passage.

In one embodiment, the main body formed by the first silicon wafer and the second silicon wafer is further provided with a first channel and a second channel. The first channel and the second channel are respectively communicated with two ends of the fluid channel. Moreover, the first channel and the second channel are communicated with the surrounding environment or the outside.

In one embodiment, the first channel and the second channel are both disposed on the first silicon wafer, or the first channel and the second channel are both disposed on the second silicon wafer, or the first channel and the second channel are respectively disposed on the first silicon wafer and the second silicon wafer.

In one embodiment, when the first channel and the second channel are both disposed on the first silicon wafer or both disposed on the second silicon wafer, the extension directions of the first channel and the second channel are the same; when the first channel and the second channel are respectively arranged on the first silicon wafer and the second silicon wafer, the extending directions of the first channel and the second channel are opposite.

In one embodiment, the fluid channel extends in a horizontal direction, and the extending directions of the first channel and the second channel are perpendicular to the extending direction of the fluid channel.

In one embodiment, a dust collecting groove is formed in the first silicon wafer and/or the second silicon wafer, an opening of the dust collecting groove faces the fluid channel, and the dust collecting groove is located at a connection position of the first channel and the fluid channel and/or a connection position of the second channel and the fluid channel. Because the extending direction of the first channel and the second channel is perpendicular to the extending direction of the fluid channel, the fluid commutates at the joint of the first channel and the fluid channel and at the joint of the second channel and the fluid channel, and the flow speed can be slowed down, so that pollutants in the fluid are deposited in the dust collection groove, the deposition of the pollutants on the sensing area is reduced, and the service life and the detection accuracy of the flow sensor are improved. In addition, the dust collection groove is arranged at the joint of the first channel and the fluid channel and/or the joint of the second channel and the fluid channel, after the dust collection groove collects pollutants, the flow sensor can be inverted relative to the first channel or the flow sensor can be inverted relative to the second channel, and the dust collection groove can be cleaned by matching with certain shaking and/or related adsorption tools.

In one embodiment, the radial dimension a of the first channel and the radial dimension b of the second channel may be equal or different.

In one embodiment, the radial dimension a of the first channel is greater than the radial dimension b of the second channel, and the first channel is configured to direct fluid flow into the fluid channel and the second channel is configured to direct fluid flow out of the fluid channel. Thus, since the cross-sectional area of the fluid inlet is larger than that of the fluid outlet, when the same volume of fluid is introduced, the differential pressure between the fluid inlet and the fluid outlet increases, so that the flow rate flowing through the sensing region increases, and the detection sensitivity can be improved.

In one embodiment, the first channel and/or the second channel are prepared using a wet etching process. The wet etching process has lower cost and is suitable for being applied to mass production.

In one embodiment, the cavity is disposed on the second silicon wafer, and an opening communicating with the surrounding environment or the outside is formed in a side of the cavity facing away from the first silicon wafer.

In one embodiment, the flow sensor further comprises a packaging substrate, the second silicon wafer is arranged on the packaging substrate through the surface of the second silicon wafer, which is away from the first silicon wafer, and at least two communication holes are formed in the packaging substrate corresponding to the opening of the cavity. On the one hand, the cavity can be communicated with the surrounding environment or the outside by providing the communication holes, and on the other hand, the probability of the pollutants entering the cavity can be reduced by providing a plurality of communication holes.

In one embodiment, the first temperature detecting unit and the second temperature detecting unit may be the same type or different types of temperature detecting units. The temperature detection unit can be a PN junction temperature sensor, a temperature sensor of metal class sensitive to temperature or a thermistor.

In one embodiment, the heating unit may be a heating metal strip, a heating wire, a PN junction heater that may enable heating, or a poly (mono) crystalline silicon heavy doping that may enable heating.

In one embodiment, the piezoresistive detection elements are polysilicon piezoresistive strips or monocrystalline silicon piezoresistive strips. The piezoresistive detection units are deployed in a Wheatstone bridge mode, and resistors in the Wheatstone bridge are replaced by the piezoresistive strips to form the piezoresistive detection units. When the insulating layer is deformed or has stress change, the piezoresistive detection unit causes the resistance value to change, so that the output current is changed, and the change of the current is regarded as the target electric signal.

In one embodiment, the piezoelectric detection unit may be a piezoelectric thin film sensor, or a piezoelectric ceramic (PTZ, piezoelectric Ceramics) sensor.

In a second aspect, there is provided a flow sensor assembly comprising the flow sensor of any one of the preceding claims, further comprising a processor. The processor is configured to process an electrical signal generated from a temperature differential change in the temperatures detected by the first and second temperature detection units for indicating one or more fluid property information and/or for generating one or more control signals. The flow sensor assembly may be provided in a small-sized electronic device and may enable high-precision fluid property detection and may be used to indicate one or more fluid property information and/or to generate one or more control signals based on the detected fluid property.

In one embodiment, the first temperature detecting unit and the second temperature detecting unit are connected with the processor, the first temperature detecting unit and the second temperature detecting unit send sensed temperature data to the processor, and the processor processes an electric signal generated according to temperature difference changes of temperatures detected by the first temperature detecting unit and the second temperature detecting unit, so as to be used for indicating one or more fluid characteristic information and/or generating one or more control signals.

In one embodiment, the heating unit is connected to the processor, and the processor controls the operating state of the heating unit. For example, the processor controls the heating unit to heat, or stops heating.

In one embodiment, the differential pressure detection unit is coupled to the processor. When the differential pressure detection unit detects that the fluid flows through the sensing area, an electric signal is generated, and the electric signal is output to the processor as a target electric signal. And the processor controls the heating unit to start heating when receiving the target electric signal.

In one embodiment, the flow sensor assembly further comprises a MOS tube. The processor controls the effective current value of the controlled module through the MOS tube, and the MOS tube is used as a control switch of the controlled module.

In one embodiment, the MOS transistor is a P-type MOS transistor, a gate and a source of the MOS transistor are connected to corresponding pins of the processor, and a drain of the MOS transistor is connected to the controlled module. The source electrode of the MOS tube is also connected with a power supply.

In one embodiment, the flow sensor assembly further comprises a substrate, at least one of the flow sensor, the processor, and the MOS transistor being disposed on the substrate.

In one embodiment, the flow sensor assembly further includes an insulating encapsulation structure disposed on the substrate. The insulating packaging structure wraps the flow sensor, the processor and the MOS tube, and the sensing area is at least partially exposed out of the insulating packaging structure.

In one embodiment, the insulating packaging structure is provided with a groove, and the sensing area is positioned at the bottom of the groove and at least partially exposed to the outside. The grooves penetrate opposite ends of the insulating package structure as part of the fluid channel.

In one embodiment, the flow sensor assembly further comprises a housing covering the insulating packaging structure, and the housing and the groove cooperate to form a fluid channel.

In one embodiment, the housing is provided with a first through hole and a second through hole which are communicated with the groove, and the housing and the insulating packaging structure form the fluid channel for fluid to flow through the first through hole, the second through hole and the groove, wherein the first through hole and the second through hole form two openings of the fluid channel.

In one embodiment, the edge portion of the insulating layer is disposed on the substrate through the substrate. The substrate is provided with a third through hole communicated with the cavity.

In one embodiment, at least one waterproof and breathable membrane is disposed in the fluid flow path. The waterproof breathable film can permit air to permeate, and can filter and isolate pollutants such as water mist and oil smoke, so that the pollutants such as water mist and oil smoke are prevented from adhering to a sensing area, and the detection accuracy is improved.

In one embodiment, at least one of the first through hole and the second through hole is provided with a waterproof and breathable film.

In one embodiment, the third through hole is provided with a waterproof and breathable membrane. Through setting up waterproof ventilated membrane in third tee bend hole department, can avoid the pollutant to enter into in the cavity, influence the effect that the cavity reduces heat loss and balanced differential pressure.

In one embodiment, the processor may be a microprocessor (MPU, microprocessor Unit), digital signal processor (Digital Signal Processing, DSP), application specific integrated circuit (Application Specific Integrated Circuit, ASIC), or Field programmable gate array (Field-Programmable Gate Array, FPGA).

In a third aspect, an electronic device is provided. The electronic device includes the flow sensor assembly of any of the above claims, and further includes a controlled module.

In one embodiment, the drain of the MOS transistor is connected to the controlled module. The processor controls the conduction of the source electrode and the drain electrode of the MOS tube so as to conduct the controlled module; or, the source electrode and the drain electrode of the MOS tube are controlled to be disconnected, so that the controlled module is turned off.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a flow sensor assembly according to embodiment 1 of the present application.

Fig. 2 is a second schematic structural diagram of the flow sensor assembly according to embodiment 1 of the present application.

Fig. 3a is a third schematic structural diagram of the flow sensor assembly according to embodiment 1 of the present application.

FIG. 3b is an exploded view of the flow sensor assembly shown in FIG. 3 a.

Fig. 4 is a schematic structural diagram of a flow sensor assembly according to embodiment 1 of the present application.

Fig. 5 is one of the sectional views of the A-A plane in fig. 4.

FIG. 6 is a cross-sectional view of the flow sensor assembly shown in FIG. 4 taken along the A-A plane after being provided with a differential pressure sensing cell.

FIG. 7 is a cross-sectional view of the flow sensor assembly of FIG. 4 taken along the A-A plane after being provided with a waterproof, breathable membrane.

Fig. 8 is a schematic distribution diagram of electronic components disposed on a sensing area in the flow sensor according to embodiment 1 of the present application.

Fig. 9 is a second schematic distribution diagram of electronic components disposed on a sensing area in the flow sensor according to embodiment 1 of the present application.

Fig. 10 is a schematic diagram of connection between a flow sensor assembly and a controlled module according to embodiment 1 of the present application.

Fig. 11 is a schematic structural diagram of a flow sensor according to embodiment 2 of the present application.

Fig. 12 is a schematic distribution diagram of electronic components disposed on a sensing area in a flow sensor according to embodiment 2 of the present application.

Fig. 13 is a second schematic structural diagram of the flow sensor according to embodiment 2 of the present application.

Fig. 14 is a third schematic structural diagram of the flow sensor according to embodiment 2 of the present application.

Fig. 15 is a schematic structural diagram of a flow sensor according to embodiment 2 of the present application.

Fig. 16 is a fifth schematic structural diagram of the flow sensor according to embodiment 2 of the present application.

Fig. 17 is a schematic diagram of a flow sensor according to embodiment 2 of the present application.

Icon: a 100-flow sensor assembly; 110 210-flow sensor; 111 211-a first temperature detection unit; 112 212-a second temperature detection unit; 113 213-heating unit; 114 214-a sensing region; 115 215-an insulating layer; 116-substrate; a 120-processor; 130-MOS tube; 140-a substrate; 141-a third through hole; 150-a controlled module; 160-insulating packaging structure; 161-grooves; 170-a housing; 171-first through holes; 172-a second through hole; 181-waterproof breathable film; 182-waterproof breathable film; 183-waterproof breathable film; 190 290-differential pressure detection cell; 191-a piezoelectric detection unit; 21-a first silicon wafer; 22-a second silicon wafer; 217-open slot; 31-a first channel; 32-a second channel; 33-a dust collection tank; 34-cavity; 41-packaging a substrate; 411-communicating holes.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. The following embodiments and features of the embodiments may be combined with each other without conflict.

Example 1

Referring to fig. 1-5, embodiment 1 of the present application provides a flow sensor 110, which includes a first temperature detecting unit 111, a second temperature detecting unit 112, a heating unit 113, and a sensing area 114. The first temperature detecting unit 111, the second temperature detecting unit 112, and the heating unit 113 are each disposed corresponding to the sensing region 114, the first temperature detecting unit 111 and the second temperature detecting unit 112 are spaced apart from each other, and the heating unit 113 is located between the first temperature detecting unit 111 and the second temperature detecting unit 112. The flow sensor 110 is coupled to the fluid channel. As fluid passes through the fluid channel, it flows through sensing region 114 under the restriction of the fluid channel. The heating unit 113 is controlled to initiate heating.

Illustratively, the sensing region 114 of the flow sensor 110 may be the region of the dashed box as shown in fig. 1.

Referring to fig. 8, the first temperature detecting unit 111 and the second temperature detecting unit 112 are spaced apart from the heating unit 113 by the same distance or nearly the same distance. After the heating unit 113 is controlled to start heating, the temperature around the heating unit 113 increases. When no fluid passes through the fluid passage, the temperatures around the heating unit 113 are symmetrically distributed, and the first temperature detecting unit 111 and the second temperature detecting unit 112 detect the same temperature, that is, the temperature difference between the temperatures detected by the first temperature detecting unit 111 and the second temperature detecting unit 112 is zero. As the fluid passes through the fluid channel, heat may be absorbed such that the temperature decreases, i.e., the fluid flow causes the sensing region 114 to create a temperature gradient, the temperature difference between the temperatures detected by the first temperature detection unit 111 and the second temperature detection unit 112 being non-zero.

Wherein the direction of fluid flow indicated by the arrows in fig. 5 is merely exemplary. It can be understood that the direction of the fluid flow may be the direction in which the first temperature detecting unit 111 points to the second temperature detecting unit 112, or may be the direction in which the second temperature detecting unit 112 points to the first temperature detecting unit 111, which can be flexibly determined according to practical situations, so long as it can be ensured that the temperature difference between the temperatures sensed by the first temperature detecting unit 111 and the second temperature detecting unit 112 is zero when no fluid flows in the fluid channel, and the temperature difference between the temperatures sensed by the first temperature detecting unit 111 and the second temperature detecting unit 112 is not zero when the fluid flows.

In this way, one or more fluid property information can be obtained according to the temperature difference change of the temperatures sensed by the first temperature detecting unit 111 and the second temperature detecting unit 112.

Specifically, when the temperature difference between the temperatures sensed by the first temperature detecting unit 111 and the second temperature detecting unit 112 is zero, it indicates that no fluid passes through the fluid channel. When the temperature difference between the temperatures sensed by the first temperature detecting unit 111 and the second temperature detecting unit 112 is not zero, it indicates that the fluid passes through the fluid channel. Further, a certain flow direction may be defined as a target flow direction, for example, a fluid flow direction indicated by an arrow in fig. 5 is defined as a target flow direction. Thus, when the temperature difference between the temperature sensed by the first temperature detecting unit 111 and the temperature sensed by the second temperature detecting unit 112 is not zero and the temperature sensed by the first temperature detecting unit 111 is lower than the temperature sensed by the second temperature detecting unit 112, it indicates that there is fluid passing through the fluid passage and the fluid flowing direction is the target flowing direction, and the fluid flows from the first temperature detecting unit 111 to the second temperature detecting unit 112. When the temperature difference between the temperature sensed by the first temperature detecting unit 111 and the temperature sensed by the second temperature detecting unit 112 is not zero and the temperature sensed by the first temperature detecting unit 111 is higher than the temperature sensed by the second temperature detecting unit 112, it indicates that there is fluid passing through the fluid passage, but the fluid flowing direction is the direction opposite to the target flowing direction, and the fluid flows from the second temperature detecting unit 112 to the first temperature detecting unit 111. In addition, the flow and/or the flow velocity of the fluid are in direct proportion to the temperature difference, and the change trend of the flow or the flow velocity can be obtained according to the temperature difference.

Based on the obtained one or more fluid property information, one or more control signals may be generated, which may be to control the operation or stop operation of the controlled module, to control the operating voltage (operating current) of the controlled module, to control the controlled module to generate alarm information, or to control the controlled module to display fluid property information, etc.

With continued reference to fig. 5, in the present embodiment, the flow sensor 110 further includes an insulating layer 115. The first temperature detecting unit 111, the second temperature detecting unit 112, and the heating unit 113 are all disposed on the insulating layer 115. Through setting up first temperature detecting element 111, second temperature detecting element 112 and heating element 113 in insulating layer 115 for first temperature detecting element 111, second temperature detecting element 112 and heating element 113 all do not expose outward, so, are favorable to insulating water or pollutant's influence, improve first temperature detecting element 111, second temperature detecting element 112 to the interference killing feature of ambient temperature detection.

In this embodiment, the flow sensor 110 further includes a substrate 116. An edge portion of the insulating layer 115 is supported on the substrate 116. The substrate 116 may be a hollow annular structure, i.e., a cavity is formed inside the substrate 116. In this way, heat conduction can be reduced when the heating unit 113 heats, thereby reducing heat loss.

Further, the cavity communicates with the surrounding environment or the outside world through the lower surface of the substrate 116. After the heating unit 113 heats, air in the cavity below the insulating layer 115 is expanded, so that the differential pressure between the upper and lower sides of the insulating layer 115 is easily increased, and the fluid channels and the cavities on the upper and lower sides of the insulating layer 115 can be prevented from forming differential pressure due to heating by communicating the cavity with the surrounding environment or the outside.

Referring to fig. 6 and 9, in the present embodiment, the flow sensor 110 further includes a differential pressure detection unit 190. Differential pressure detection cell 190 is disposed corresponding to sensing region 114. The differential pressure detection unit 190 generates an electrical signal upon detecting that fluid is flowing through the sensing region 114, and the heating unit 113 controllably initiates heating based on the electrical signal.

In the present embodiment, the differential pressure detecting unit 190 is an electronic component with lower power consumption than the heating unit 113. For example, differential pressure sensing element 190 may be a piezoresistive sensing element or a piezoelectric sensing element 191.

In this embodiment, differential pressure detection unit 190 may initially detect whether there is fluid flowing through sensing region 114. When no fluid flows through the sensing region 114, the heating unit 113 does not operate to reduce power consumption. When there is a fluid flowing through the sensing region 114, the differential pressure detecting unit 190 detects that the fluid flowing through the sensing region 114 outputs a target electric signal, the heating unit 113 controllably starts heating based on the target electric signal, and then, high-precision detection of the fluid characteristics is performed using the first temperature detecting unit 111 and the second temperature detecting unit 112. In this way, the problem that the heating unit 113 needs to be continuously heated when no fluid flows, resulting in large power consumption, can be improved, and the detection of the fluid characteristics with high accuracy and low power consumption can be achieved.

Referring again to fig. 6, a differential pressure detecting unit 190 may be disposed in the insulating layer 115, and may determine whether a fluid flows through the sensing region 114 by sensing whether the insulating layer 115 is deformed or stressed.

Specifically, if no fluid is flowing in the fluid channel, the insulating layer 115 will not deform or undergo a stress change. If fluid flow is present in the fluid channel, a pressure difference between the cavity and the fluid channel may be changed, thereby causing the insulating layer 115 to be easily deformed or to generate a stress change. Both the piezoresistive detecting elements and the piezoelectric detecting element 191 can generate corresponding electrical signals due to deformation or stress variation of the insulating layer 115. In this way, it is possible to determine whether the insulating layer 115 is deformed or changed in stress based on the electrical signal output from the piezoresistive detecting means or the piezoelectric detecting means 191, thereby determining whether the fluid flow exists in the fluid channel. Further, the heating unit 113 is controlled to start heating when fluid flows in the fluid channel, so that the heating unit 113 can start working when needed, and power consumption is effectively reduced.

Referring to fig. 6 and fig. 9 in combination, fig. 9 can be regarded as a schematic diagram of the distribution of the corresponding electronic components on the sensing region 114 in a top view. The piezoelectric detection unit 191 may have a ring structure and be disposed on the insulating layer 115. The piezoelectric detection unit 191 may detect deformation or stress variation of the insulating layer 115, and in case that the insulating layer 115 is deformed or stress variation occurs, generate an electrical signal, and output the electrical signal as a target electrical signal, and the heating unit 113 starts to operate based on the target electrical signal and heats.

The first temperature detection unit 111 and the second temperature detection unit 112 may be the same type or different types of temperature detection units. The temperature detection unit may be, but is not limited to, a PN junction temperature sensor, a temperature sensor of a temperature sensitive metal type, a thermistor, etc.

The heating unit 113 may be, but is not limited to, a heating metal bar, a heating metal wire, a PN junction heater that can achieve heating, poly (mono) crystalline silicon heavy doping that can achieve heating, and the like.

The piezoresistive detection elements may be polysilicon piezoresistive strips, or monocrystalline silicon piezoresistive strips. For example, the piezoresistive detection elements may be deployed by way of a wheatstone bridge. That is, the resistors in the wheatstone bridge are replaced with the piezoresistive strips in the present embodiment to form the piezoresistive detection elements. The piezoresistive detecting unit may cause a change in resistance when the insulating layer 115 is deformed or a stress change occurs, thereby changing the magnitude of the output current, and the change in current may be regarded as a target electrical signal.

The piezoelectric detection unit 191 may be, but not limited to, a piezoelectric thin film sensor, or a piezoelectric ceramic (PTZ, piezoelectric Ceramics) sensor, and may generate an electrical signal in the event of deformation or stress change of the insulating layer 115.

Referring again to fig. 1-5, embodiment 1 of the present application further provides a flow sensor assembly 100 including a flow sensor 110 and a processor 120. The processor 120 is configured to process an electrical signal generated from a temperature differential change in the temperatures detected by the first temperature detection unit 111 and the second temperature detection unit 112 for indicating one or more fluid property information and/or for generating one or more control signals.

The flow sensor 110 is integrated to a good degree, which is advantageous for miniaturization of electronic devices, and the flow sensor assembly 100 can be disposed in small-sized electronic devices, and can realize high-precision fluid characteristic detection, and is used for indicating one or more pieces of fluid characteristic information and/or generating one or more control signals according to the detected fluid characteristics.

For example, the flow sensor assembly 100 may be disposed in an electronic cigarette, and in particular, at a mouthpiece portion of the electronic cigarette, it being understood that it may also be disposed at any location in a channel of the electronic cigarette that is in fluid communication with the mouthpiece portion. When the flow sensor assembly 100 is operated, the heating unit 113 may be heated after being energized, so that the temperature around the heating unit 113 increases. The first temperature detection unit 111 and the second temperature detection unit 112 may sense an ambient temperature. When the user does not suck through the suction nozzle portion, no fluid passes through the fluid channel, the temperature around the heating unit 113 is symmetrically distributed, and the temperature difference between the temperatures detected by the first temperature detecting unit 111 and the second temperature detecting unit 112 is zero. When the user sucks through the suction nozzle portion, fluid passes through the fluid passage, and the temperature difference between the temperatures detected by the first temperature detecting unit 111 and the second temperature detecting unit 112 is not zero. When the pumping action of the user is not detected, the processor 120 controls the heating module of the electronic cigarette to not heat or stop heating; upon detecting a user's pumping action, the processor 120 controls the heating module of the e-cigarette to begin heating so that the aerosol-forming substrate (tobacco tar, paste or leaf) is heated to form an aerosol for use by the user.

Further, whether the user inhales or blows through the suction nozzle of the electronic cigarette can be judged through the fluid flow direction, and the suction actions of the user can be accurately distinguished. If the temperature sensed by the first temperature detecting unit 111 is higher than the temperature sensed by the second temperature detecting unit 112, the fluid flow direction is: the fluid flows from the second temperature detection unit 112 to the first temperature detection unit 111. If the temperature sensed by the first temperature detecting unit 111 is lower than the temperature sensed by the second temperature detecting unit 112, the fluid flow direction is: the fluid flows from the first temperature detection unit 111 to the second temperature detection unit 112. Based on this, in the e-cigarette, the flow sensor assembly 100 may detect the user's inspiratory behavior and the expiratory behavior. The air suction action is to suck air through a suction nozzle part of the electronic cigarette; the gas-discharge behavior is that the user discharges gas through the suction nozzle part of the electronic cigarette.

The flow sensor assembly 100 controls the heating module of the electronic cigarette to start heating when detecting the inspiration; when the gas spouting behavior is detected, the heating module is not operated, or the heating module which is being heated is controlled to stop operating, so that the heating is stopped. Therefore, the accuracy of detecting the smoking behavior of the user can be improved, and the influence on the user experience caused by the fact that the heating module continues to heat when the user exhales can be avoided. In addition, a signal for controlling an alarm module of the electronic cigarette may be generated based on the inhalation or exhalation behavior detected by the flow sensor assembly 100, and the alarm module is controlled to transmit alarm information to indicate that the smoking behavior of the user is incorrect when the user performs the exhalation behavior.

Further, the flow rate and/or the flow velocity of the fluid are/is proportional to the temperature difference, and the change trend of the flow rate or the flow velocity can be obtained according to the temperature difference, so that the suction force can be judged according to the flow rate (flow velocity), and the working voltage (working current) of the heating module can be adjusted.

Referring to fig. 10, the first temperature detecting unit 111 and the second temperature detecting unit 112 are connected to the processor 120, and the first temperature detecting unit 111 and the second temperature detecting unit 112 can send sensed temperature data to the processor 120, so that the processor 120 can process an electrical signal generated according to a temperature difference change of the temperatures detected by the first temperature detecting unit and the second temperature detecting unit, for indicating one or more fluid property information, and/or for generating one or more control signals.

Further, the heating unit 113 is also connected to the processor 120, and the processor 120 may control the operation state of the heating unit 113, for example, the processor 130 may control the heating unit 113 to heat, or stop heating.

Further, a differential pressure detection unit 190 is also coupled to the processor 120. When differential pressure detection unit 190 detects that there is fluid flowing through sensing region 114, an electrical signal is generated and output to processor 120 as a target electrical signal. Upon receiving the target electrical signal, the processor 120 determines that fluid is flowing through the sensing region 114, and at this time, controls the heating unit 113 to start operating and heat.

With continued reference to fig. 10, the flow sensor assembly 100 further includes a MOS tube 130. The MOS tube 130 is used as a control switch of the controlled module 150 by controlling the effective current value of the controlled module 150 through the MOS tube 130.

The MOS transistor 130 may be a P-type MOS transistor, and a Gate (G) and a Source (S) of the MOS transistor 130 may be connected to corresponding pins of the processor 120. The Drain (Drain, D) of MOS transistor 130 may be connected to controlled module 150. The source of MOS transistor 130 may also be connected to a power source, which may be used to power controlled module 150. Of course, the power supply may also supply power to other modules, for example, the heating unit 113, the processor 120, and so on.

In this way, the processor 120 can control the level (voltage) of the gate of the MOS transistor 130 according to the temperature difference between the temperatures sensed by the first temperature detecting unit 111 and the second temperature detecting unit 112, so as to realize the on/off of the source and the drain in the MOS transistor 130. In addition, the processor 120 can adjust the current between the MOS transistor 130 and the controlled module 150 by adjusting the gate voltage of the MOS transistor 130.

As can be appreciated, the processor 120 can control the source and drain of the MOS transistor 130 to be periodically turned on and off to achieve power adjustment of the controlled module 150 by PWM (Pulse Width Modulation ). Generally, the longer the source and drain of the MOS transistor 130 are turned on in a single period, the larger the effective current value of the controlled module 150, and the larger the operating power of the controlled module 150. The effective current value may be determined by a conventional calculation method, which is not described herein. The temperature difference is formed when the heating unit 113 is operated and there is fluid flowing through the sensing region 114 of the flow sensor 110, and the MOS transistor 130 is used as a control switch of the controlled module 150.

For example, when the temperature difference is zero, the processor 120 controls the turn-off of the source and the drain in the MOS transistor 130, so that the controlled module 150 can be in the turn-off state. When the temperature difference is not zero, the processor 120 controls the conduction of the source and the drain in the MOS transistor 130, so that the controlled module 150 can be in an operation state. The type and parameters of the MOS transistor 130 may be flexibly selected according to practical situations, and the operation mode of the MOS transistor 130 is a conventional technology, which is not described herein.

In other embodiments, the processor 120 may directly adjust the voltage of the gate of the MOS transistor 130, so as to control the magnitude of the current output by the MOS transistor 130, so as to control the effective current value of the controlled module 150, without controlling the effective current value of the controlled module 150 by the period of periodic conduction.

Referring to fig. 1, the flow sensor assembly 100 further includes a substrate 140 on which at least one of the flow sensor 110, the processor 120, and the MOS transistor 130 is disposed. In one embodiment, flow sensor 110, processor 120, and MOS transistor 130 are all disposed on substrate 140.

Flow 5 flow sensor assembly 100 is formed by integrating flow sensor 110, processor 120, and MOS transistor 130 on substrate 140. The processor 120 detects based on the first temperature detection unit 111 and the second temperature detection unit 112

The temperature difference of the measured temperature changes, and high-sensitivity detection of the fluid characteristics can be realized. In addition, the processor 120 can control the effective current value of the controlled module 150 through the MOS transistor 130 based on the variation of the temperature difference, which is beneficial to improving the accuracy and reliability of controlling the controlled module 150.

Referring to fig. 2 and 5, the flow sensor assembly 100 may further include an insulating package 0 structure 160 disposed on the substrate 140. The insulating encapsulation structure 160 encapsulates the flow sensor 110, the processor 120, and the MOS transistor 130, wherein,

the sensing region 114 of the flow sensor 110 is at least partially exposed from the insulating encapsulation structure 160.

When the insulating package structure 160 is provided, the flow sensor 110, the processor 120, and the MOS transistor 130 may be molded on the substrate 140 by a conventional molding process, thereby forming the insulating package structure 160. Wherein the flow rate

The sensing region 114 of the sensor 110 needs to be at least partially exposed to the fluid channel in order to more sensitively sense the 5 flow of fluid. In addition, the material of the insulating package structure 160 can be flexibly determined according to practical situations, and can be but

Not limited to insulating plastics, insulating resins, insulating rubbers, and the like.

It is understood that the insulating package structure 160 may insulate the exposed pins of the flow sensor 110, the processor 120 and the MOS transistor 130, and protect the flow sensor 110, the processor 120 and the MOS transistor 130,

Short circuits of the flow sensor 110, the processor 120 and the MOS tube 130 due to bare pins are avoided, and damage to the flow sensor 110, the processor 120 and the MOS tube 130 due to external force 0 is avoided.

Referring again to fig. 2, the insulating package structure 160 may have a trench 161, and the sensing region 114 of the flow sensor 110 is located at the bottom of the trench 161 and at least partially exposed to the outside.

The grooves 161 penetrate opposite ends of the insulating encapsulation structure 160 as a part of the fluid passage. Due to sensing

The region 114 is located at the bottom of the groove 161, so that the sensing region 114 is not easily damaged by external force, i.e., the groove 1615 can guide fluid, so as to improve the sensitivity and detection accuracy of the flow sensor 110 for sensing the fluid flow,

in addition, the sensing region 114 of the flow sensor 110 can be protected, which is beneficial to improving the reliability of the product. Referring to fig. 3a and 3b in combination, the flow sensor assembly 100 may further include a housing 170 covering the insulating package 160. Fig. 3a is a schematic view of the case 170 covering the insulating package 160, and fig. 3b is a schematic view

Is illustrated with the housing 170 disengaged from the insulating package 160. The housing 170 is used to cover the insulating package 160. The housing 170 is provided with a first through hole 171 and a second through hole 172 which are communicated with the groove 161, the housing 170 and the insulating packaging structure 160 form a fluid channel for fluid to flow through the first through hole 171, the second through hole 172 and the groove 161, wherein the first through hole 171 and the second through hole 172 form two openings of the fluid channel, and the sensing region 114 is positioned in the housing 170 and at least partially positioned in the fluid channel.

In the present embodiment, the shape of the housing 170 can be flexibly determined according to the actual situation. For example, referring to fig. 3b, the housing 170 may be a rectangular cover with an opening, and the rectangular cover is covered on the insulating package structure 160 through the opening. For example, referring to fig. 4, the housing 170 may be a rectangular cover plate directly covering the insulating package structure 160. At this time, the housing 170 does not cover both ends of the groove 161, the housing 170 and the groove 161 are directly engaged to form a fluid passage, and the openings at both ends of the groove 161 can be directly used as the openings of the fluid passage without additionally providing the first through hole 171 and the second through hole 172.

The housing 170 may protect the sensing region 114. The number and arrangement positions of the first through holes 171 and the second through holes 172 can be flexibly determined according to practical situations, as long as the fluid can flow into the fluid channel through one of the first through holes 171 and the second through holes 172 and flow out of the fluid channel through the other of the first through holes 171 and the second through holes 172, and the fluid passes through the sensing area 114 when flowing in the fluid channel, so that the sensing area 114 can sense the fluid characteristics of the fluid in the fluid channel.

For example, referring to fig. 3b, a first through hole 171 may be disposed on a side wall of the housing 170 and used for communicating with an opening of one end of the groove 161 of the insulating package structure 160, and a second through hole 172 may be disposed on a top of the housing 170 and communicating with a cavity formed by the groove 161 and the housing 170.

In other embodiments, the first through hole 171 and the second through hole 172 may be provided on opposite side walls of the housing 170, and communicate with both ends of the groove 161, respectively.

Referring to fig. 5, an edge portion of the insulating layer 115 is disposed on the substrate 140 through the substrate 116. The substrate 140 is provided with a third through hole 141 communicating with the cavity. The heating unit 113 expands air in the cavity below the insulating layer 115 after heating, which easily increases the differential pressure between the upper and lower sides of the insulating layer 115, and the third through holes 141 allow the cavity to communicate with the surrounding environment or the outside, which can be used to avoid differential pressure between the cavities and the fluid channels on the upper and lower sides of the insulating layer 115 due to heating.

Referring to fig. 4 and 7 in combination, in the present embodiment, at least one of the first through hole 171, the second through hole 172 and the third through hole 141 may be provided with a waterproof and breathable film. For example, the first through hole 171, the second through hole 172, and the third through hole 141 are provided with a waterproof and breathable film 181, a waterproof and breathable film 182, and a waterproof and breathable film 183, respectively. The waterproof breathable film can permit air to permeate, and can filter and isolate pollutants such as water mist, lampblack and the like. The first through hole 171 and the second through hole 172 are located on the fluid flow path, and by arranging the waterproof and breathable film at the first through hole 171 and/or the second through hole 172, the attachment of pollutants such as water mist, oil smoke and the like in the sensing area 114 is avoided, and the detection accuracy is improved. In addition, by providing a waterproof and breathable membrane at the third through-hole 141, contaminants can be prevented from entering the cavity, which affects the effect of the cavity in reducing heat loss and balancing differential pressure.

In this embodiment, the processor 120 may be, but is not limited to, a microprocessor (MPU, microprocessor Unit), a digital signal processor (Digital Signal Processing, DSP), an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), a Field programmable gate array (Field-Programmable Gate Array, FPGA), etc., which may be used for signal processing.

The embodiment 1 of the application also provides electronic equipment. The electronics may include a controlled module 150 and the flow sensor assembly 100 described in the above embodiments. The electronic device may be any type of small-sized device that requires detection of a characteristic of the fluid.

The drain of MOS transistor 130 may be connected to controlled module 150. The flow sensor assembly 100 may utilize the processor 120 to control the conduction of the source and drain of the MOS transistor 130 to conduct the controlled module 150; alternatively, the source and drain of the MOS transistor 130 are controlled to be disconnected to turn off the controlled module 150. The controlled module 150, as a controlled module, may be flexibly determined according to actual conditions.

For example, referring to fig. 10, the electronic device may be an electronic cigarette, and the controlled module 150 is a heating module of the electronic cigarette. The processor 120 may control the heating power of the heating module by controlling the on-time of the MOS transistor 130 in a unit time. The processor 120 may control the source and drain of the MOS transistor 130 to be always turned on, and at this time, the heating power of the heating module may be maximized. Alternatively, the processor 120 may control the source and drain of the MOS transistor 130 to be turned on and off periodically to realize the heating power adjustment of the heating module. In one period, the on-off time length can be flexibly determined according to actual conditions. The duration of a single period can be flexibly determined according to practical situations, for example, the single period can be 500 milliseconds, 1 second, etc. of shorter duration.

In this embodiment, the heating unit 113 may continuously heat during the operation process, and during the operation process, when fluid passes through the sensing area 114 of the flow sensor 110, the temperature distribution of the sensing area 114 may change, where the temperature difference magnitude has a corresponding relationship with the air flow magnitude, so the processor 120 may learn the air flow magnitude by detecting the temperature difference magnitude of the first temperature detecting unit 111 and the second temperature detecting unit 112, and then adjust the periodic conduction duration of the source and the drain of the MOS tube 130 based on the air flow magnitude, so as to realize the heating power adjustment of the heating module. For example, the larger the airflow, the longer the source and drain of the control MOS tube 130 are turned on in a single cycle, so that the heating power of the heating module is larger.

When the flow sensor assembly 100 is applied to the electronic cigarette, the flow sensor assembly can be directly installed in the air passage of the electronic cigarette, the design of an external air passage is not needed, and the cost is saved. In addition, the piezoresistive or piezoelectric type detection unit 191 is used as the differential pressure detection unit 190 with lower accuracy but low power consumption, and can be monitored for a long time. When the electronic cigarette works, the heating unit 113, the first temperature detecting unit 111 and the second temperature detecting unit 112 are used as thermal conduction type fluid detecting units, so that the fluid characteristics including whether the fluid exists, the flow direction of the fluid and the flow rate (flow) can be detected with high sensitivity and high precision, and the requirements of the electronic cigarette on low power consumption and high measurement precision can be met.

In addition, according to the temperature of the first temperature detecting unit 111 and the second temperature detecting unit 112, the air flow direction can be judged, for example, when the flow sensor assembly 100 is applied to an electronic cigarette, the air suction and blowing actions can be identified, so that the heating module of the electronic cigarette can be prevented from being triggered by blowing mistakenly, and the user experience and the product reliability can be improved.

During long-term use of the electronic cigarette, the aerosol-forming substrate is accumulated and attached to the surface of the sensor in the form of atomized steam, so that the sensor chip is disabled. However, the sensors employed by conventional electronic cigarettes for detecting puffs cannot distinguish whether the sensors are contaminated with aerosol-forming substrates.

In the present application, the piezoresistive detection unit or the piezoelectric detection unit 191 senses the change of the external applied pressure through the stress change; the heat conduction type fluid detection unit formed by the first temperature detection unit 111, the second temperature detection unit 112 and the heating unit 113 is to change the temperature distribution of the sensing area 114 due to the fluid flowing through the sensing area 114, and to obtain the fluid characteristics of the passing fluid by monitoring the temperature change of the sensing area 114. Due to the different principles of piezoresistive (or piezoelectric) and thermal conductive operation, the sensitivity to the aerosol-forming substrate is different, and by comparing the output relationships of the piezoresistive (or piezoelectric) detection unit and the temperature detection unit (referred to as the first temperature detection unit 111 and the second temperature detection unit 112), it can be determined whether the sensing region 114 or the flow sensor 110 is contaminated by the aerosol-forming substrate. For example, in the case where the sensing region 114 is free of aerosol-forming substrate contamination, the ratio of the current values output by the piezoresistive (or piezoelectric) detection unit and the temperature detection unit is within a set range. If the ratio is not within the set range, it indicates that the sensing region 114 or the flow sensor 110 has been contaminated with aerosol-forming substrate. The setting range may be flexibly determined according to practical situations, and is not specifically limited herein.

When the processor 120 determines that the sensing region 114 or the flow sensor 110 has been contaminated with the aerosol-forming substrate, the aerosol-forming substrate may be evaporated by physical heating of the chip contaminated with the aerosol-forming substrate and/or the correction of the current value output by the temperature detection unit may be calibrated by a preset algorithm. The preset algorithm is to correct the current value of the temperature detection unit by using the corresponding relation between the current value of the piezoresistive (or piezoelectric) detection unit and the current value of the temperature detection unit when aerosol forms substrate pollution, and then determine the temperature value sensed by the temperature detection unit by using the corrected current value. In this manner, the accuracy of fluid detection can also be improved in the event that the aerosol-forming substrate contaminates the sensing region 114.

As described above, in the present embodiment, the flow sensor assembly 100 is formed by integrating the flow sensor 110, the processor 120 and the MOS transistor 130 on the substrate 140. The processor 120 can realize highly sensitive detection of the fluid characteristics based on the temperature difference change of the temperatures detected by the first temperature detecting unit 111 and the second temperature detecting unit 112. In addition, the processor 120 can control the effective current value of the controlled module 150 through the MOS transistor 130 based on the variation of the temperature difference, which is beneficial to improving the accuracy and reliability of controlling the controlled module 150.

Example 2

Referring to fig. 11 and 12, embodiment 2 of the present application provides a flow sensor 210, which includes a first temperature detecting unit 211, a second temperature detecting unit 212, a heating unit 213, and a sensing area 214. The first temperature detecting unit 211, the second temperature detecting unit 212, and the heating unit 213 are disposed corresponding to the sensing region 214, the first temperature detecting unit 211 and the second temperature detecting unit 212 are spaced apart from each other, and the heating unit 213 is located between the first temperature detecting unit 211 and the second temperature detecting unit 212. The flow sensor 210 also includes a fluid channel. As fluid passes through the fluid channel, it flows through sensing region 214 under the restriction of the fluid channel. The heating unit 213 is controlled to initiate heating.

Illustratively, the sensing region 214 of the flow sensor 210 may be the region of the solid line box as shown in fig. 12.

The first temperature detecting unit 211 and the second temperature detecting unit 212 are identical or nearly identical in pitch with the heating unit 213. After the heating unit 213 is controlled to start heating, the temperature around the heating unit 213 increases. When no fluid passes through the fluid passage, the temperatures around the heating unit 213 are symmetrically distributed, and the first temperature detecting unit 211 and the second temperature detecting unit 212 detect the same temperature, i.e., the temperature difference between the temperatures detected by the first temperature detecting unit 211 and the second temperature detecting unit 212 is zero. As the fluid passes through the fluid channel, heat may be removed such that the overall temperature decreases while the fluid flow causes a temperature gradient to occur in sensing region 214, the temperature difference between the temperatures detected by first temperature detection unit 211 and second temperature detection unit 212 being non-zero.

Wherein the direction of fluid flow indicated by the arrows in fig. 11 is merely exemplary. It can be understood that the direction of the fluid flow may be the direction in which the first temperature detecting unit 211 points to the second temperature detecting unit 212, or may be the direction in which the second temperature detecting unit 212 points to the first temperature detecting unit 211, which can be flexibly determined according to practical situations, so long as it can be ensured that the temperature difference between the temperatures sensed by the first temperature detecting unit 211 and the second temperature detecting unit 212 is zero when no fluid flows in the fluid channel, and the temperature difference between the temperatures sensed by the first temperature detecting unit 211 and the second temperature detecting unit 212 is not zero when the fluid flows.

In this way, one or more fluid property information can be obtained according to the temperature difference change of the temperatures sensed by the first temperature detecting unit 211 and the second temperature detecting unit 212.

Specifically, when the temperature difference between the temperatures sensed by the first temperature detecting unit 211 and the second temperature detecting unit 212 is zero, it indicates that no fluid passes through the fluid channel. When the temperature difference between the temperatures sensed by the first temperature detecting unit 211 and the second temperature detecting unit 212 is not zero, it indicates that the fluid passes through the fluid channel. Further, a certain flow direction may be defined as a target flow direction, for example, a fluid flow direction indicated by an arrow in fig. 11 is defined as a target flow direction. Thus, when the temperature difference between the temperature sensed by the first temperature sensing unit 211 and the temperature sensed by the second temperature sensing unit 212 is not zero and the temperature sensed by the first temperature sensing unit 211 is lower than the temperature sensed by the second temperature sensing unit 212, it indicates that there is fluid passing through the fluid passage and the fluid flowing direction is the target flowing direction, and the fluid flows from the first temperature sensing unit 211 to the second temperature sensing unit 212. When the temperature difference between the temperature sensed by the first temperature sensing unit 211 and the temperature sensed by the second temperature sensing unit 212 is not zero and the temperature sensed by the first temperature sensing unit 211 is higher than the temperature sensed by the second temperature sensing unit 212, it indicates that there is fluid passing through the fluid passage, but the fluid flowing direction is the direction opposite to the target flowing direction, and the fluid flows from the second temperature sensing unit 212 to the first temperature sensing unit 211. In addition, the flow and/or the flow velocity of the fluid are in direct proportion to the temperature difference, and the change trend of the flow or the flow velocity can be obtained according to the temperature difference.

With continued reference to fig. 11, in the present embodiment, the flow sensor 210 further includes an insulating layer 215. The first temperature detecting unit 211, the second temperature detecting unit 212, and the heating unit 213 are all disposed on the insulating layer 215. Through setting up first temperature detecting element 211, second temperature detecting element 212 and heating element 213 in insulating layer 215 for first temperature detecting element 211, second temperature detecting element 212 and heating element 213 all do not expose outward, so, are favorable to insulating water or pollutant's influence, improve first temperature detecting element 211, second temperature detecting element 212 to the interference killing feature of ambient temperature detection.

Referring to fig. 11 and 12, in the present embodiment, the flow sensor 210 further includes a differential pressure detection unit 290. Differential pressure detection unit 290 is disposed corresponding to sensing region 214. The differential pressure detection unit 290 generates an electrical signal upon detecting fluid flow through the sensing region 214, and the heating unit 213 controllably initiates heating based on the electrical signal.

In this embodiment, the differential pressure detecting unit 290 is an electronic component with lower power consumption than the heating unit 213. For example, differential pressure sensing element 290 may be a piezoresistive sensing element or a piezoelectric sensing element.

In this embodiment, differential pressure detection unit 290 may initially detect whether fluid is flowing through sensing region 214. When no fluid flows through the sensing region 214, the heating unit 213 does not operate to reduce power consumption. When there is a fluid flowing through the sensing region 214, the differential pressure detecting unit 290 detects that the fluid flowing through the sensing region 214 outputs a target electric signal, the heating unit 213 controllably starts heating based on the target electric signal, and then, high-precision detection of the fluid characteristics is performed using the first temperature detecting unit 211 and the second temperature detecting unit 212. In this way, the problem that the heating unit 213 needs to be continuously heated when no fluid flows, resulting in large power consumption can be improved, and the detection of the fluid characteristics with high accuracy and low power consumption can be achieved.

Differential pressure detection unit 290 may be disposed in insulating layer 215 and may determine whether fluid is flowing through sensing region 214 by sensing whether insulating layer 215 is deformed or stressed.

Specifically, if no fluid is flowing in the fluid channel, the insulating layer 215 is not deformed or does not change stress. If there is fluid flow in the fluid channel, the insulating layer 215 is easily deformed or subjected to stress variation. Both the piezoresistive detecting elements and the piezoelectric detecting elements can generate corresponding electrical signals due to deformation or stress variation of the insulating layer 215. In this way, it can be determined whether the insulating layer 215 is deformed or changed in stress based on the electrical signal output from the piezoresistive detection unit or the piezoelectric detection unit, thereby determining whether the fluid flow exists in the fluid channel. Further, the heating unit 213 is controlled to start heating when fluid flows in the fluid channel, so that the heating unit 213 can start working when needed, and power consumption is effectively reduced.

Referring to fig. 11 and fig. 12 in combination, fig. 12 can be regarded as a schematic diagram of the distribution of the corresponding electronic components on the sensing region 214 in a top view. The differential pressure detecting units 290 are four and are symmetrically disposed on the insulating layer 215. The differential pressure detecting unit 290 may detect deformation or stress variation of the insulating layer 215, and in case that the insulating layer 215 is deformed or the stress variation occurs, generate an electrical signal, and output the electrical signal as a target electrical signal, and the heating unit 213 starts to operate based on the target signal and heats.

With continued reference to fig. 11, the flow sensor 210 includes a first silicon wafer 21 and a second silicon wafer 22, wherein the first silicon wafer 21 and the second silicon wafer 22 are stacked and bonded to form a body, and a gap between the first silicon wafer 21 and the second silicon wafer 22 forms a fluid channel. By stacking, bonding, etc., the two silicon wafers form a fluid channel at the silicon wafer level, which is advantageous for reducing manufacturing costs and for reducing subsequent package size, and the flow sensor 210 has a smaller finished size, which is advantageous for application in small electronic devices (e.g., electronic cigarettes). The bonding manner of the first silicon wafer 21 and the second silicon wafer 22 includes any one of si—si bonding, si—o—si bonding, eutectic bonding, and glass paste bonding.

It should be noted that the positions of the first silicon wafer 21 and the second silicon wafer 22 for bonding are generally a portion of the peripheral side adjacent edge of the first silicon wafer 21 and a portion of the peripheral side adjacent edge of the second silicon wafer 22, and functional components on the first silicon wafer 21 and the second silicon wafer 22 are avoided when bonding.

One of the first silicon wafer 21 and the second silicon wafer 22 is provided with an open groove 217 with respect to the other to increase the gap between the first silicon wafer 21 and the second silicon wafer 22, thereby increasing the radial dimension of the fluid passage, i.e., increasing the sectional area of the fluid passage.

As shown in fig. 11 for example, the surface of the first silicon wafer 21 opposite to the second silicon wafer 22 is provided with an open groove 217, and the first temperature detecting unit 211, the second temperature detecting unit 212 and the heating unit 213 are provided on the surface of the second silicon wafer 22 opposite to the first silicon wafer 21, and the open groove 217 and the surface of the second silicon wafer 22 opposite to the first silicon wafer 21 cooperate to form a fluid passage.

With continued reference to fig. 11, a main body formed by the first silicon wafer 21 and the second silicon wafer 22 is further provided with a first channel 31 and a second channel 32. The first channel 31 and the second channel 32 are respectively communicated with both ends of the fluid channel. Furthermore, the first channel 31 and the second channel 32 are both in communication with the surrounding environment or the outside. That is, one of the first channel 31 and the second channel 32 serves as an inflow channel for guiding a fluid to flow into the fluid channel, and the other of the first channel 31 and the second channel 32 serves as an outflow channel for guiding a fluid to flow out of the fluid channel.

The fluid channels extend in a horizontal direction, and the extending directions of the first and

second channels

31 and 32 are perpendicular to the extending directions of the fluid channels, i.e., the first and

second channels

31 and 32 extend in a vertical direction. Referring to fig. 16 and 17, the first channel 31 and the second channel 32 may be disposed on the first silicon wafer 21 or on the second silicon wafer 22; referring to fig. 11, the first channel 31 and the second channel 32 may be disposed on the first silicon wafer 21 and the second silicon wafer 22, respectively, i.e., the first channel 31 is disposed on the first silicon wafer 21, the second channel 32 is disposed on the second silicon wafer 22, or the first channel 31 is disposed on the second silicon wafer 22, and the second channel 32 is disposed on the first silicon wafer 21. When the first channel 31 and the second channel 32 are both disposed on the first silicon wafer 21 or both disposed on the second silicon wafer 22, the extending directions of the first channel 31 and the second channel 32 are the same. When the first channel 31 and the second channel 32 are provided on the first silicon wafer 21 and the second silicon wafer 22, respectively, the extending directions of the first channel 31 and the second channel 32 are opposite.

As shown in fig. 11, the fluid channels extend in the horizontal direction, the first channel 31 and the second channel 32 extend in the vertical direction, and the extending directions of the first channel 31 and the second channel 32 are opposite, the first channel 31 is disposed on the first silicon wafer 21 and extends upward in the vertical direction, and the second channel 32 is disposed on the second silicon wafer 22 and extends downward in the vertical direction.

With continued reference to fig. 11, a dust collecting groove 33 is formed on the first silicon wafer 21 and/or the second silicon wafer 22, the opening of the dust collecting groove 33 faces to the fluid channel, and the dust collecting groove 33 is located at the connection between the first channel 31 and the fluid channel and/or the connection between the second channel 32 and the fluid channel. Since the extending direction of the first channel 31 and the second channel 32 is perpendicular to the extending direction of the fluid channel, the fluid is reversed at the connection of the first channel 31 and the fluid channel, and the fluid is reversed at the connection of the second channel 32 and the fluid channel, so that the flow rate is slowed down, thereby facilitating the deposition of the pollutants in the fluid in the dust collection groove 33, further reducing the deposition of the pollutants on the sensing area 214, and facilitating the improvement of the service life and the detection accuracy of the flow sensor 210.

In addition, by arranging the dust collecting tank 33 at the connection position of the first channel 31 and the fluid channel and/or at the connection position of the second channel 32 and the fluid channel, after the dust collecting tank 33 collects the pollutants, the flow sensor 110 can be inverted relative to the first channel 31, or the flow sensor 110 can be inverted relative to the second channel 32, and a certain shaking and/or related adsorbing tool can be matched, so that the cleaning effect on the dust collecting tank 33 can be achieved.

Referring to fig. 11 and 13, the radial dimension a of the first channel 31 and the radial dimension b of the second channel 32 may be equal or different. In one embodiment, the radial dimension a of the first channel 31 is greater than the radial dimension b of the second channel 32, and the first channel 31 is used to guide the fluid to flow into the fluid channel, and the second channel 32 is used to guide the fluid to flow out of the fluid channel, so that, when the same volume of fluid is introduced, the differential pressure between the fluid inlet and the fluid outlet increases, so that the flow velocity flowing through the sensing area 214 increases, and the detection sensitivity can be improved.

Referring to fig. 11 and 14 in combination, the first channel 31 and the second channel 32 may be channels with uniform radial dimensions or non-uniform radial dimensions based on a specific processing process. When the radial dimensions are not uniform, the radial dimension a of the first channel 31 refers to the radial dimension at the junction of the first channel 31 and the fluid channel, and similarly, the radial dimension b of the second channel 32 refers to the radial dimension at the junction of the second channel 32 and the fluid channel. In one embodiment, the first channel 31 and/or the second channel 32 are prepared by a wet etching process, which is relatively inexpensive and suitable for mass production applications. As shown in fig. 14, the first channel 31 prepared by the wet etching process is trumpet-shaped, and the radial dimension of the first channel 31 is gradually reduced along the vertical downward direction.

With continued reference to fig. 11, the second silicon wafer 32 is provided with a cavity 34, and the first temperature detecting unit 211, the second temperature detecting unit 212 and the heating unit 213 are located between the fluid channel and the cavity 34. The cavity 34 is filled with air, and the thermal conductivity coefficient of the air is smaller than that of the second silicon wafer 32, so that heat loss is reduced, and the detection precision of the first temperature detection unit 211 and the second temperature detection unit 212 is improved. The side of the cavity 34 away from the first silicon wafer 31 is provided with an opening communicated with the surrounding environment or the outside, the air in the cavity 34 expands after being heated, and the cavity 34 can be communicated with the outside or the surrounding environment through the opening, so that differential pressure generated by heating of the heating unit 213 in the fluid channel and the cavity 34 is avoided.

Referring to fig. 15, the flow sensor 210 further includes a package substrate 41. The second silicon wafer 22 is disposed on the package substrate 41 through its surface facing away from the first silicon wafer 21, and at least two communication holes 411 are disposed on the package substrate 41 corresponding to the openings of the cavities 34. On the one hand, the cavity 34 can be made to communicate with the surrounding environment or the outside by providing the communication holes 411, and on the other hand, the probability of entry of contaminants into the cavity 34 can be reduced by providing a plurality of communication holes 411.

The first temperature detecting unit 31 and the second temperature detecting unit 32 may be the same type or different types of temperature detecting units. The temperature detection unit may be, but is not limited to, a PN junction temperature sensor, a temperature sensor of a temperature sensitive metal type, a thermistor, etc.

The heating unit 213 may be, but is not limited to, a heating metal bar, a heating wire, a PN junction heater that can achieve heating, multi (mono) crystalline silicon heavy doping that can achieve heating, etc.

The piezoresistive detection elements may be polysilicon piezoresistive strips, or monocrystalline silicon piezoresistive strips. For example, the piezoresistive detection elements may be deployed by way of a wheatstone bridge. That is, the resistors in the wheatstone bridge are replaced with the piezoresistive strips in the present embodiment to form the piezoresistive detection elements. The piezoresistive detecting unit may cause a change in resistance when the insulating layer 215 is deformed or a stress change occurs, so as to change the magnitude of the output current, and the change in current may be regarded as a target electrical signal.

The piezoelectric type detection unit may be, but not limited to, a piezoelectric thin film sensor, or a piezoelectric ceramic sensor, and may generate an electrical signal in the event of deformation or stress variation of the insulating layer 215.

The embodiment 2 of the present application further provides a flow sensor assembly, including a flow sensor 210, and further including a processor, where the setting mode of the processor and the matching relationship between the flow sensor 210 and the processor are the same as those of embodiment 1, and are not described herein again.

Further, the flow sensor assembly further includes a MOS tube, and the arrangement manner of the MOS tube and the matching relationship between the MOS tube and the flow sensor 210 and the processor are the same as those in embodiment 1, which is not described herein.

Further, the flow sensor assembly further includes a substrate, and the arrangement manner of the substrate and the matching relationship between the substrate and the flow sensor 210, the processor and the MOS transistor are the same as those in embodiment 1, which is not described herein. In one embodiment, the substrate and the package substrate 41 are the same element.

The embodiment 2 of the application also provides electronic equipment. The electronics may include a controlled module and the flow sensor assembly described in the above embodiments, and the electronics may be any of a variety of small-sized devices that require detection of a characteristic of the fluid. The arrangement manner of the controlled module and the matching relationship between the controlled module and the flow sensor assembly are the same as those in embodiment 1, and are not described here again.

The foregoing is merely exemplary embodiments of the present application and is not intended to limit the scope of the present application, and various modifications and variations may be suggested to one skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. The utility model provides a flow sensor, its characterized in that includes first temperature detection unit, second temperature detection unit, heating unit and sensing area, first temperature detection unit second temperature detection unit with heating unit all corresponds to the sensing area sets up, first temperature detection unit with second temperature detection unit separates each other, just heating unit is located between first temperature detection unit and the second temperature detection unit, flow sensor still includes fluid channel, perhaps, flow sensor cooperatees with fluid channel, and when fluid passes through fluid channel's restriction flows through the sensing area, heating unit controlled start-up heats.

2. The flow sensor of claim 1, further comprising a detection unit that generates an electrical signal when fluid flow through the sensing region is detected, the heating unit being controlled to initiate heating based on the electrical signal.

3. The flow sensor according to claim 2, wherein the detection unit is a differential pressure detection unit provided corresponding to the sensing region, the differential pressure detection unit being configured to detect deformation or stress variation generated when a fluid flows through the sensing region to generate an electrical signal, the heating unit being configured to controllably activate heating based on the electrical signal.

4. The flow sensor of claim 3, further comprising an insulating layer, wherein the first temperature sensing unit, the second temperature sensing unit, the heating unit, and the differential pressure sensing unit are all disposed on the insulating layer.

5. The flow sensor of claim 4, further comprising a cavity, wherein the insulating layer is positioned between the fluid channel and the cavity, wherein the cavity is in communication with the ambient environment or the outside world.

6. The flow sensor of any one of claims 1-5, wherein the flow sensor comprises a first silicon die and a second silicon die, wherein the first silicon die and the second silicon die are stacked and bonded to form a body, and wherein a gap between the first silicon die and the second silicon die forms the fluid channel.

7. The flow sensor of claim 6, wherein the body is provided with a first channel and a second channel, the first channel and the second channel are respectively communicated with two ends of the fluid channel, and the first channel and the second channel are also communicated with the surrounding environment or the outside.

8. The flow sensor of claim 7, wherein the first channel and the second channel are each disposed on the first silicon wafer, or wherein the first channel and the second channel are each disposed on the second silicon wafer, or wherein the first channel and the second channel are each disposed on the first silicon wafer and the second silicon wafer.

9. A flow sensor assembly comprising the flow sensor of any of claims 1-8, further comprising a processor for processing an electrical signal generated from a temperature differential change in the temperatures detected by the first temperature detection unit and the second temperature detection unit for indicating one or more fluid property information, and/or for generating one or more control signals.

10. An electronic device comprising the flow sensor assembly of claim 9, further comprising a controlled module.