阅读说明：本技术 一种机械灵敏度和测量范围可调的硅微流速计 (Silicon micro-flow velocity meter with adjustable mechanical sensitivity and measuring range ) 是由 杨波 郭鑫 梁卓玥 陈新茹 姜勇昌 郑翔 于 2020-05-12 设计创作，主要内容包括：本发明公开了一种可以实现微流速敏感的机械灵敏度和测量范围可调的硅微流速计的三层结构方案。具体为作为信号接收层的金属立柱,作为信号转化层的硅微机械结构,以及作为信号输出层的玻璃绝缘层及其信号引线。金属立柱通过紫外线固化胶粘合在硅微机械结构上表面的中心位置,硅微机械结构的通过硅-玻璃键合技术固定在玻璃绝缘层上表面,硅微机械的锚点与玻璃绝缘层的金属引线位置相对应,从而实现电信号的输入输出控制。本发明通过给两组音叉型谐振器施加带有不同直流偏置信号的交流驱动电压,由于静电负刚度效应,改变静电弱耦合谐振结构的静电耦合刚度,从而进一步改变硅微流速计的机械灵敏度和测量范围。(The invention discloses a three-layer structure scheme of a silicon micro-flow meter capable of realizing micro-flow rate sensitivity and adjustable mechanical sensitivity and measurement range. In particular to a metal upright post used as a signal receiving layer, a silicon micro-mechanical structure used as a signal conversion layer, a glass insulating layer used as a signal output layer and a signal lead thereof. The metal upright post is adhered to the center of the upper surface of the silicon micro-mechanical structure through ultraviolet curing glue, the silicon micro-mechanical structure is fixed on the upper surface of the glass insulating layer through a silicon-glass bonding technology, and the anchor point of the silicon micro-mechanical corresponds to the position of the metal lead of the glass insulating layer, so that the input and output control of an electric signal is realized. According to the invention, the alternating current driving voltages with different direct current bias signals are applied to the two groups of tuning fork type resonators, and the electrostatic coupling rigidity of the electrostatic weak coupling resonance structure is changed due to the electrostatic negative rigidity effect, so that the mechanical sensitivity and the measurement range of the silicon micro-flow velocity meter are further changed.)

1. The utility model provides a mechanical sensitivity and measuring range adjustable silicon micro flow meter which characterized in that: the silicon micro-flow meter adopts a three-layer structure, specifically a metal upright post (1) as a signal receiving layer, a silicon micro-mechanical structure as a signal conversion layer, and a glass insulating layer (7) and a signal lead thereof as a signal output layer;

the metal upright post (1) is adhered to the central position of the upper surface of the silicon micro-mechanical structure through ultraviolet curing glue and is used for sensing the flow rate information of the outside;

the silicon micromechanical structure is fixed on the upper surface of the glass insulating layer (7) through a silicon-glass bonding technology, and anchor points of the silicon micromechanical structure correspond to the metal lead position of the glass insulating layer (7), so that input and output control of electric signals is realized;

the silicon micro-mechanical structure consists of a base tray (5), two groups of first and second differential output micro-levers (3-1 and 3-2), two groups of first and second electrostatic weak coupling resonance structures (2-1 and 2-2), and first, second, third and fourth directional decoupling structures (4-1, 4-2, 4-3 and 4-4) and is used for converting an external flow velocity signal into an electric signal capable of being directly measured;

two groups of first and second differential output micro-levers (3-1 and 3-2) are respectively arranged at the upper and lower positions of a base tray (5) and are connected with the base tray (5) through first and second input decoupling beams (3-1-1 and 3-2-1);

two groups of first and second electrostatic weak coupling structures (2-1 and 2-2) are respectively arranged at the left and right positions of the base tray (5) and are respectively connected with first, second, third and fourth output beams (3-1-6, 3-1-7, 3-2-6 and 3-2-7) of the first and second differential output micro levers (3-1 and 3-2);

the first, second, third and fourth directional decoupling structures (4-1, 4-2, 4-3, 4-4) are arranged at four positions of the upper left, lower right and upper right of the base tray (5) and are respectively connected with the base tray (5) through the first, second, third and fourth directional decoupling beams (4-1-2, 4-4-2, 4-3-2, 4-2-2).

2. The silicon micro-flowmeter with adjustable mechanical sensitivity and measurement range of claim 1, wherein: wherein the first and second differential output micro-levers (3-1, 3-2) have the same structure;

the first differential output micro-lever (3-1) consists of a first input decoupling beam (3-1-1), two first and second output beams (3-1-6 and 3-1-7), two first and second supporting beams (3-1-9 and 3-1-8), two first and second micro-levers (3-1-4 and 3-1-5) and two first and second lever anchor points (3-1-2 and 3-1-3) and is used for amplifying input acting force;

the first input decoupling beam (3-1-1) is respectively connected with one end of the two first and second micro levers (3-1-4 and 3-1-5); the first lever anchor point (3-1-2) is connected to the middle position of the first micro lever (3-1-4) through a first supporting beam (3-1-9), one end of the first output beam (3-1-6) is connected with the first electrostatic weak coupling resonance structure (2-1), and the other end of the first output beam is connected to the other end of the first micro lever (3-1-4), so that an A-type micro lever structure is formed;

the second lever anchor point (3-1-3) is connected to the other end of the second micro lever (3-1-5) through a support beam II (3-1-8), one end of the second output beam (3-1-7) is connected with the second electrostatic weak coupling structure (2-2), and the other end of the second output beam is connected to the middle position of the second micro lever (3-1-5), so that a B-type micro lever structure is formed.

3. The silicon micro-flowmeter with adjustable mechanical sensitivity and measurement range of claim 1, wherein: wherein the first and second electrostatic weak coupling resonance structures (2-1, 2-2) have the same structure;

the first electrostatic weak coupling resonance structure (2-1) consists of two groups of first and second tuning fork type resonators (2-1-1 and 2-1-2) and is used for converting a micro-force signal into a capacitance signal which can be measured by a matched circuit; the first tuning fork resonator (2-1-1) comprises a first tuning fork resonant beam (2-1-1-9), first and second electrostatic coupling comb capacitors (2-1-1-7 and 2-1-1-8), first and second driving capacitor comb teeth (2-1-1 and 2-1-1-2), first, second, third and fourth detection capacitor comb teeth (2-1-1-3, 2-1-1-4, 2-1-1-5 and 2-1-1-6),

the second tuning fork resonator (2-1-2) comprises a second tuning fork resonant beam (2-1-2-9), two groups of third and fourth electrostatic coupling comb capacitors (2-1-2-7 and 2-1-2-8), third and fourth driving capacitor comb capacitors (2-1-2-1 and 2-1-2-2), and fifth, sixth, seventh and eighth detection capacitor comb capacitors (2-1-2-3, 2-1-2-4, 2-1-2-5 and 2-1-2-6);

the first tuning fork resonator (2-1-1) is arranged in the middle of the second tuning fork resonator (2-1-2), one side of the middle part of each resonant beam of the two groups of first and second tuning fork resonators (2-1-1 and 2-1-2) is respectively connected with first, second, third and fourth electrostatic coupling capacitance comb teeth (2-1-1-7, 2-1-1-8, 2-1-2-7 and 2-1-2-8), the first and third electrostatic coupling capacitance comb teeth (2-1-1-7 and 2-1-2-7) are oppositely arranged to form a first electrostatic coupling comb tooth group, the second and fourth electrostatic coupling capacitance comb teeth (2-1-1-8 and 2-1-2-8) are oppositely arranged to form a second electrostatic coupling comb tooth group, the arrangement directions of the electrostatic coupling comb tooth groups are all horizontal directions;

the other side of the middle part of each resonant beam of the first tuning fork resonator (2-1-1, 2-1-2) and the second tuning fork resonator (2-1-1, 2-1-2-1, 2-1-2-2) is connected with a driving detection capacitor comb tooth, the first driving capacitance comb tooth, the second driving capacitance comb tooth, the third driving capacitance comb tooth and the fourth driving capacitance comb tooth are oppositely inserted with the driving detection capacitor comb tooth to form a driving comb tooth group,

the first, second, third, fourth, fifth, sixth, seventh and eighth detection capacitance comb teeth (2-1-1-3, 2-1-1-4, 2-1-1-5, 2-1-1-6, 2-1-2-3, 2-1-2-4, 2-1-2-5 and 2-1-2-6) and the driving detection capacitance comb teeth are oppositely inserted to form a detection comb tooth group;

one end of the first tuning fork resonator (2-1-1) is connected with the second output beam (3-1-7) of the first differential output micro lever (3-1) and the second differential output micro lever (3-1), and the other end of the first tuning fork resonator is connected with the fourth output beam (3-2-7) of the first differential output micro lever and the second differential output micro lever (3-2).

4. The silicon micro-flowmeter with adjustable mechanical sensitivity and measurement range of claim 1, wherein: wherein the first, second, third and fourth directional decoupling structures (4-1, 4-2, 4-3 and 4-4) have the same structure; the first direction decoupling structure (4-1) consists of a first decoupling anchor point (4-1-1) and a first direction decoupling beam (4-1-2) and is used for ensuring the good 8-shaped direction characteristic of the sensor; one end of the first direction decoupling beam (4-1-2) is connected with the first decoupling anchor point (4-1-1).

5. The silicon micro-flowmeter with adjustable mechanical sensitivity and measurement range of claim 1, wherein: wherein, the first, second, third and fourth electrodes (6-3-1, 6-3-2, 6-3-3, 6-3-4) are respectively bonded with the first, second and third four detection capacitance comb teeth (2-1-1-3, 2-1-1-4, 2-1-1-5, 2-1-1-6) of the first electrostatic weak coupling resonance structure (2-1) and are connected with the first and second detection signal extraction electrodes (6-1-1, 6-1-2) through leads;

the fifth electrode (6-3-5) and the sixth electrode (6-3-6) are respectively bonded with the first driving capacitance comb tooth (2-1-1-1, 2-1-1-2) and the second driving capacitance comb tooth (2-1-1, 2-1-1-2) of the first electrostatic weak coupling resonance structure (2-1) and are connected with the first driving signal extraction electrode (6-1-3, 6-1-4) and the second driving signal extraction electrode (6-1-3, 6-1-4) through leads;

seventh and eighth electrodes (6-4-5, 6-4-6) are respectively bonded with the third and fourth groups of driving capacitance comb teeth (2-1-2-1, 2-1-2-2) of the first electrostatic weak coupling resonance structure (2-1), and are connected with the third and fourth driving signal leading-out electrodes (6-2-3, 6-2-4) through leads;

wherein the ninth, tenth, eleventh and twelfth electrodes (6-4-1, 6-4-2, 6-4-3 and 6-4-4) are respectively bonded with the fifth, sixth, seventh and eighth detection capacitance comb teeth (2-1-2-3, 2-1-2-4, 2-1-2-5 and 2-1-2-6) of the first electrostatic weak coupling resonance structure (2-1) and are connected with the third and fourth detection signal extraction electrodes (6-2-1 and 6-2-2) through leads;

thirteenth and fourteenth electrodes (6-7-5, 6-7-6) are respectively bonded with fifth and sixth driving capacitance comb teeth (2-2-1-1, 2-2-1-2) of the second electrostatic weak coupling resonance structure (2-2), and are connected with fifth and sixth driving signal extraction electrodes (6-5-3, 6-5-4) through leads; fifteenth and sixteenth electrodes (6-8-5 and 6-8-6) are respectively bonded with seventh and eighth driving capacitance comb teeth (2-2-2-1 and 2-2-2-2) of the second electrostatic weak coupling resonance structure (2-2) and are connected with seventh and eighth driving signal extraction electrodes (6-6-3 and 6-6-4) through leads;

seventeenth, eighteenth, nineteenth and twenty electrodes (6-9-1, 6-9-2, 6-9-4 and 6-9-4) are respectively bonded with the third and fourth tuning fork resonant beams (2-1-2-9 and 2-2-2-9) and are connected with the first and second electrostatic common leading-out electrodes (6-10-1 and 6-10-2) through leads; the twenty-first and twenty-second electrodes (6-11-1, 6-11-2) are bonded with the common end of the silicon microflow velocity meter and are connected with the first and second common end leading-out electrodes (6-12-1, 6-12-2) through leads;

twenty-third, twenty-fourth, twenty-fifth and twenty-sixth electrodes (6-7-1, 6-7-2, 6-7-3 and 6-7-4) are respectively bonded with ninth, tenth, eleventh and twelfth detection capacitance comb teeth (2-2-1-3, 2-2-1-4, 2-2-1-5 and 2-2-1-6) of the second electrostatic weak coupling resonance structure (2-2) and are connected with fifth and sixth detection signal extraction electrodes (6-5-1 and 6-5-2) through leads;

twenty-seventh, twenty-eighth, twenty-ninth and thirty-electrodes (6-8-1, 6-8-2, 6-8-3 and 6-8-4) are respectively bonded with thirteenth, fourteen, fifteen and sixteen detection capacitance comb teeth (2-2-2-3, 2-2-2-4, 2-2-2-5 and 2-2-2-6) of the second electrostatic weak coupling resonance structure (2-2) and are connected with seventh and eighth detection signal extraction electrodes (6-6-1 and 6-6-2) through leads.

Technical Field

The invention relates to the field of micro-electromechanical systems and micro-fluid sensitivity, in particular to a silicon micro-flow meter with adjustable mechanical sensitivity and measuring range.

Background

Micro Electro Mechanical System (MEMS) sensors are key devices for acquiring information, have a great promoting effect on miniaturization of various sensing devices, and have been widely applied in the fields of space satellites, carrier rockets, aerospace equipment, airplanes, various vehicles, biomedical and consumer electronics, and the like.

A silicon micro-flowmeter is a sensor that combines microelectronics and micromachining technologies. The silicon micro-flow velocity meter can continuously measure the fluid flow velocity of a peripheral flow field, is suitable for measuring the environmental flow velocity in the industries of electric power, steel, petrifaction, energy conservation and the like, and has great attention in the environmental identification application of the micro-autonomous system robot which is concerned at present.

In recent years, research institutions at home and abroad have started to perform certain research on silicon microflow velocity meters. Gijs j. krijnen et al, university of tun, the netherlands, have studied a bionic fluid sensor, all of which adopt a capacitance signal generator to transform flow rate signals, can realize the sensitivity to an external flow field, and can be further applied to fluid cameras, auditory sensitivity and other scenes. However, most of the current researches on silicon micro-flow meters cannot be considered in terms of two important indexes, namely mechanical sensitivity and measurement range, namely, the larger the mechanical sensitivity is, the smaller the measurement range is. Conversely, to increase the measurement range, a sacrifice in mechanical sensitivity must be made.

Disclosure of Invention

In order to solve the problems, the invention discloses a silicon micro-flowmeter with adjustable mechanical sensitivity and measuring range, which has the characteristics of high mechanical sensitivity, large measuring range, high environmental stability and the like, and the mechanical sensitivity and the measuring range of the flowmeter can be adjusted by an external control circuit, so that more practical application requirements are met.

In order to achieve the purpose, the invention adopts the technical scheme that:

a silicon micro-flow velocity meter with adjustable mechanical sensitivity and measuring range adopts a three-layer structure, specifically a metal upright post as a signal receiving layer, a silicon micro-mechanical structure as a signal conversion layer, and a glass insulating layer and a signal lead thereof as a signal output layer;

the metal upright post is adhered to the central position of the upper surface of the silicon micro-mechanical structure through ultraviolet curing glue and is used for sensing the flow rate information of the outside;

the silicon micromechanical structure is fixed on the upper surface of the glass insulating layer by a silicon-glass bonding technology, and anchor points of the silicon micromechanical structure correspond to the metal lead position of the glass insulating layer, so that the input and output control of electric signals is realized;

the silicon micro-mechanical structure consists of a base tray, two groups of first and second differential output micro-levers, two groups of first and second electrostatic weak coupling resonance structures and first, second, third and fourth directional decoupling structures and is used for converting an external flow velocity signal into an electric signal which can be directly measured;

the two groups of first and second differential output micro-levers are respectively arranged at the upper and lower positions of the base tray and are connected with the base tray through first and second input decoupling beams;

the two groups of first and second electrostatic weak coupling structures are respectively arranged at the left and right positions of the base tray and are respectively connected with the first, second, third and fourth output beams of the first and second differential output micro-levers.

The first, second, third and fourth directional decoupling structures are arranged at four positions of the upper left, lower right and upper right of the base tray and are respectively connected with the base tray through the first, second, third and fourth directional decoupling beams.

The invention further improves that: wherein the first and second differential output micro-lever structures are completely the same; the first differential output micro-lever consists of a first input decoupling beam, two first and second output beams, two first and second supporting beams, two first and second micro-levers and two first and second lever anchor points and is used for amplifying an input acting force;

the first input decoupling beam is respectively connected with one ends of the two first and second micro levers; the first lever anchor point is connected to the middle position of the first micro lever through a first supporting beam, one end of the first output beam is connected with the first electrostatic weak coupling resonance structure, and the other end of the first output beam is connected to the other end of the first micro lever, so that an A-type micro lever structure is formed;

the second lever anchor point is connected at the other end of the second micro lever through a support beam II, one end of the second output beam is connected with the second electrostatic weak coupling structure, and the other end of the second output beam is connected at the middle position of the second micro lever, so that a B-type micro lever structure is formed.

The invention further improves that: the first and second electrostatic weak coupling resonance structures have the same structure;

the first electrostatic weak coupling resonance structure consists of two groups of first and second tuning fork type resonators and is used for converting a micro-force signal into a capacitance signal which can be measured by a matching circuit; the first tuning fork resonator comprises a first tuning fork resonant beam, a first electrostatic coupling comb capacitor, a second electrostatic coupling comb capacitor, a first driving capacitor comb, a second driving capacitor comb, a first detection capacitor comb, a second detection capacitor comb, a third detection capacitor comb and a fourth detection capacitor comb,

the second tuning fork resonator comprises a second tuning fork resonator beam, two groups of third and fourth electrostatic coupling comb capacitors, third and fourth driving capacitor comb teeth, fifth, sixth, seventh and eighth detection capacitor comb teeth, the first tuning fork resonator is arranged in the middle of the second tuning fork resonator,

one side of the middle part of each resonant beam of the two groups of first and second tuning fork resonators is respectively connected with first, second, third and fourth electrostatic coupling capacitor comb teeth, the first and third electrostatic coupling capacitor comb teeth are oppositely arranged in an inserting manner to form a first electrostatic coupling comb tooth group, the second and fourth electrostatic coupling capacitor comb teeth are oppositely arranged in an inserting manner to form a second electrostatic coupling comb tooth group, and the arrangement directions of the electrostatic coupling comb tooth groups are horizontal directions; the other side of the middle part of each resonant beam of the first tuning fork resonator and the second tuning fork resonator is connected with drive detection capacitor comb teeth, the first drive capacitor comb teeth, the second drive capacitor comb teeth, the third drive capacitor comb teeth and the fourth drive capacitor comb teeth are oppositely inserted with the drive detection capacitor comb teeth to form a drive comb teeth group,

the first, second, third, fourth, fifth, sixth, seventh and eighth detection capacitor comb teeth and the drive detection capacitor comb teeth are oppositely inserted to form a detection comb tooth group;

one end of the first tuning fork resonator is connected with the second output beam of the first differential output micro lever and the second differential output micro lever, and the other end of the first tuning fork resonator is connected with the fourth output beam of the first differential output micro lever and the fourth output beam of the second differential output micro lever.

The invention further improves that: the first, second, third and fourth directional decoupling structures have the same structure; the first directional decoupling structure consists of a first decoupling anchor point and a first directional decoupling beam and is used for ensuring the good 8-shaped directional characteristic of the sensor; one end of the first direction decoupling beam is connected with the first decoupling anchor point.

The invention further improves that: the first electrode, the second electrode, the third electrode and the fourth electrode are respectively bonded with the first detection capacitor comb teeth, the second detection capacitor comb teeth and the third detection capacitor comb teeth of the first electrostatic weak coupling resonance structure and are connected with the first detection signal extraction electrode and the second detection signal extraction electrode through leads;

the fifth electrode and the sixth electrode are respectively bonded with the first driving capacitor comb teeth and the second driving capacitor comb teeth of the first electrostatic weak coupling resonance structure and are connected with the first driving signal extraction electrode and the second driving signal extraction electrode through leads;

the seventh electrode and the eighth electrode are respectively bonded with the third group of driving capacitor comb teeth and the fourth group of driving capacitor comb teeth of the first electrostatic weak coupling resonance structure and are connected with the third driving signal extraction electrode and the fourth driving signal extraction electrode through leads;

the ninth electrode, the tenth electrode, the eleventh electrode and the twelfth electrode are respectively bonded with the fifth detection capacitor comb teeth, the sixth detection capacitor comb teeth, the seventh detection capacitor comb teeth and the eighth detection capacitor comb teeth of the first electrostatic weak coupling resonance structure and are connected with the third detection signal extraction electrode and the fourth detection signal extraction electrode through leads;

the thirteenth electrode and the fourteenth electrode are respectively bonded with the fifth driving capacitor comb tooth and the sixth driving capacitor comb tooth of the second electrostatic weak coupling resonance structure and are connected with the fifth driving signal extraction electrode and the sixth driving signal extraction electrode through leads; the fifteenth electrode and the sixteenth electrode are respectively bonded with the seventh driving capacitor comb tooth and the eighth driving capacitor comb tooth of the second electrostatic weak coupling resonance structure and are connected with the seventh driving signal extraction electrode and the eighth driving signal extraction electrode through leads;

seventeenth, eighteenth, nineteenth and twenty electrodes are respectively bonded with the third and fourth tuning fork resonant beams and are connected with the first and second electrostatic common leading-out electrodes through leads; the twenty-first and twenty-second electrodes are bonded with the common end of the silicon micro-flow meter and are connected with the first and second common end leading-out electrodes through leads.

The twenty-third, twenty-fourth, twenty-fifth and twenty-sixth electrodes are respectively bonded with the ninth, tenth, eleventh and twelfth detection capacitor comb teeth of the second weak electrostatic coupling resonance structure and are connected with the fifth and sixth detection signal extraction electrodes through leads;

twenty-seventh, twenty-eighth, twenty-ninth and thirty electrodes are respectively bonded with the thirteenth, fourteen, fifteen and sixteen detection capacitor comb teeth of the second electrostatic weak coupling resonance structure and are connected with the seventh and eighth detection signal extraction electrodes through leads.

When the silicon micro-flow velocity meter with adjustable mechanical sensitivity and measurement range is arranged in a horizontal air flow field, fluid acting force caused by friction resistance and pressure difference resistance on the surface of a metal upright post acts on a tuning fork resonant beam of an external tuning fork type resonator of an electrostatic weak coupling resonant structure through a differential output micro-lever, and acting forces generated on the tuning fork resonant beam by an A-type micro-lever structure and a B-type micro-lever structure are opposite in direction, so that the mechanical rigidity of the tuning fork resonant beam is changed, the characteristic vector of the electrostatic weak coupling resonant structure is changed, and finally the difference is generated by the vibration amplitudes of two groups of tuning fork type resonators. The air flow velocity in the horizontal flow field can be obtained by measuring the change of the ratio of the vibration amplitudes of the two groups of tuning fork resonators.

According to the invention, the alternating current driving voltages with different direct current bias signals are applied to the two groups of tuning fork type resonators, and the electrostatic coupling rigidity of the electrostatic weak coupling resonance structure is changed due to the electrostatic negative rigidity effect, so that the mechanical sensitivity and the measurement range of the silicon micro-flow velocity meter are further changed.

Furthermore, when alternating-current driving voltage is applied to the driving capacitor comb teeth of the electrostatic weak coupling resonance structure, two groups of tuning fork resonance beams can generate forced vibration. The alternating current signal generated on the detection comb teeth is input into the closed-loop phase-locked circuit after passing through the capacitance-voltage conversion circuit, and the frequency of the applied alternating current driving voltage can be locked at the resonant frequency of the electrostatic weak coupling resonant structure.

Furthermore, when alternating current driving voltages with different direct current bias signals are applied to the driving capacitor comb teeth of the two groups of tuning fork resonators, electrostatic force can be generated on the electrostatic coupling comb tooth groups, and electrostatic coupling rigidity of the electrostatic weak coupling resonance structure is changed due to the electrostatic negative rigidity effect. The mechanical sensitivity and the measurement range of the silicon micro-flow velocity meter are both related to the electrostatic coupling rigidity, specifically, when the electrostatic coupling rigidity is increased, the mechanical sensitivity of the silicon micro-flow velocity meter is increased, and the measurement range is reduced; when the electrostatic coupling rigidity is reduced, the mechanical sensitivity of the silicon micro-flow meter is reduced, and the measurement range is increased. Therefore, by varying the DC bias of the AC drive voltage, the mechanical sensitivity and measurement range of the silicon micro-flowmeter can be varied.

Has the advantages that: compared with the prior art, the invention has the following advantages:

and a directional decoupling structure is adopted to ensure that the directional output signal of the silicon micro-flow velocity meter is in an 8 shape.

A, B two different types of micro-lever structures are adopted, the force amplification factor is consistent through parameter adjustment, the direction is opposite, and the axial force acting on the tuning fork resonant beam due to the external air flow rate is favorably improved, so that the silicon micro-flow rate and the performance are improved.

The arrangement mode that one group of tuning fork type resonators are arranged inside the other group of tuning fork type resonators is adopted, so that full coupling between two tuning fork type resonance beams of the tuning fork type resonators is realized, and the symmetry of the tuning fork type resonance beams during vibration is ensured.

The two groups of tuning fork type sensors are coupled in a motion mode in an electrostatic coupling mode, and the magnitude of the negative rigidity of the electrostatic coupling can be changed through an external control circuit, so that the micro flow rate of silicon and the mechanical sensitivity and the measurement range can be changed to adapt to different measurement requirements.

Drawings

FIG. 1 is a schematic view of the overall mechanical structure of the present invention;

FIG. 2 is a schematic diagram of a silicon micromechanical structure according to the present invention;

FIG. 3a is a schematic view of a first electrostatic weak coupling resonance structure according to the present invention;

FIG. 3b is a schematic diagram of a second electrostatic weak coupling resonance structure according to the present invention;

FIG. 4a is a schematic diagram of a first differential output microlever according to the present invention;

FIG. 4b is a schematic diagram of a second differential output microlever according to the present invention;

FIG. 5 is a schematic view of the directional decoupling structure of the present invention;

FIG. 6 is a schematic view of a glass insulating layer and signal lead-out wires according to the present invention.

Detailed Description

The present invention will be further illustrated with reference to the accompanying drawings and specific embodiments, which are to be understood as merely illustrative of the invention and not as limiting the scope of the invention. It should be noted that the terms "front," "back," "left," "right," "upper" and "lower" used in the following description refer to directions in the drawings, and the terms "inner" and "outer" refer to directions toward and away from, respectively, the geometric center of a particular component.

As shown in fig. 1, the silicon micro-flowmeter with adjustable mechanical sensitivity and measurement range provided by the invention adopts a three-layer structure, specifically, a metal pillar 1 as a signal receiving layer, a silicon micro-mechanical structure as a signal transforming layer, and a glass insulating layer 7 and a signal lead thereof as a signal output layer. The metal upright column 1 is adhered to the central position of the upper surface of the silicon micro-mechanical structure through ultraviolet curing glue and is used for sensing the flow velocity signal of the outside; the silicon micro-mechanical structure is fixed on the upper surface of the glass insulating layer 7 through a silicon-glass bonding technology, and anchor points of the silicon micro-mechanical structure correspond to the metal lead positions of the glass insulating layer 7, so that input and output control of electric signals is achieved.

As shown in fig. 2, the silicon micro-mechanical structure is composed of a base tray 5, two groups of first and second differential output micro-levers 3-1 and 3-2, two groups of first and second electrostatic weak coupling resonance structures 2-1 and 2-2, and first, second, third and fourth directional decoupling structures 4-1, 4-2, 4-3 and 4-4, and is used for converting an external flow velocity signal into an electrical signal capable of being directly measured; the first differential output micro-lever 3-1 and the second differential output micro-lever 3-2 are respectively arranged at the upper position and the lower position of the base tray 5 and are connected with the base tray 5 through the first input decoupling beam 3-1-1 and the second input decoupling beam 3-2-1; the first and second electrostatic weak coupling structures 2-1 and 2-2 are respectively arranged at the left and right positions of the base tray 5 and are respectively connected with the first, second, third and fourth output beams 3-1-6, 3-1-7, 3-2-6 and 3-2-7 of the first and second differential output micro-levers 3-1 and 3-2. The first, second, third and fourth directional decoupling structures 4-1, 4-2, 4-3 and 4-4 are arranged at four positions of the upper left, lower right and upper right of the base tray 5 and are respectively connected with the base tray 5 through the first, second, third and fourth directional decoupling beams 4-1-2, 4-4-2, 4-3-2 and 4-2-2.

As shown in fig. 3a and 3b, the two sets of differential output micro-levers 3-1, 3-2 are identical in structure. Specifically, taking the first differential output micro-lever 3-1 as an example,

the first differential output micro-lever 3-1 consists of a first input decoupling beam 3-1-1, two first and second output beams 3-1-6 and 3-1-7, two first and second support beams 3-1-9 and 3-1-8, two first and second micro-levers 3-1-4 and 3-1-5 and two first and second lever anchor points 3-1-2 and 3-1-3 and is used for amplifying input acting force;

the first input decoupling beam 3-1-1 is respectively connected with one end of two first and second micro levers 3-1-4 and 3-1-5; the first lever anchor point 3-1-2 is connected to the middle position of the first micro lever 3-1-4 through a first supporting beam 3-1-9, one end of the first output beam 3-1-6 is connected with the first electrostatic weak coupling resonance structure 2-1, and the other end is connected to the other end of the first micro lever 3-1-4, so that an A-type micro lever structure is formed;

the second lever anchor point 3-1-3 is connected to the other end of the second micro lever 3-1-5 through a support beam II 3-1-8, one end of the second output beam 3-1-7 is connected with the second electrostatic weak coupling structure 2-2, and the other end is connected to the middle position of the second micro lever 3-1-5, so that a B-type micro lever structure is formed.

As shown in fig. 4a and 4b, the first and second electrostatic weak coupling resonant structures 2-1 and 2-2 have the same structure; the first electrostatic weak coupling resonance structure 2-1 consists of two groups of first and second tuning fork type resonators 2-1-1 and 2-1-2 and is used for converting a micro-force signal into a capacitance signal which can be measured by a matched circuit; the first tuning fork resonator 2-1-1 comprises a first tuning fork resonator beam 2-1-1-9, first and second electrostatic coupling comb capacitors 2-1-1-7 and 2-1-1-8, first and second driving capacitor comb capacitors 2-1-1 and 2-1-1-2, and first, second, third and fourth detection capacitor comb capacitors 2-1-1-3, 2-1-1-4, 2-1-1-5 and 2-1-1-6;

the second tuning fork resonator 2-1-2 comprises a second tuning fork resonator beam 2-1-2-9, two groups of third and fourth electrostatic coupling comb capacitors 2-1-2-7 and 2-1-2-8, third and fourth driving capacitor comb capacitors 2-1-2-1 and 2-1-2-2, fifth, sixth, seventh and eighth detection capacitor comb capacitors 2-1-2-3, 2-1-2-4, 2-1-2-5 and 2-1-2-6;

the first tuning fork resonator 2-1-1 is arranged in the middle of the second tuning fork resonator 2-1-2, one side of the middle part of each resonant beam of the two groups of first and second tuning fork resonators 2-1-1 and 2-1-2 is respectively connected with first, second, third and fourth electrostatic coupling capacitor comb teeth 2-1-7, 2-1-1-8, 2-1-2-7 and 2-1-2-8, the first, third and 2-1-1-7 and 2-1-2-7 are oppositely arranged to form a first electrostatic coupling comb tooth group, the second, fourth and 2-1-1-8 comb teeth 2-1-2-8 are oppositely arranged to form a second electrostatic coupling comb tooth group, the arrangement directions of the electrostatic coupling comb tooth groups are all horizontal directions;

the other side of the middle part of each resonant beam of the first tuning fork resonator 2-1-1 and the second tuning fork resonator 2-1-2 is connected with a driving detection capacitor comb tooth, the first, second, third and fourth driving capacitor comb teeth 2-1-1, 2-1-1-2, 2-1-2-1 and 2-1-2-2 are oppositely inserted with the driving detection capacitor comb teeth to form a driving comb tooth group, and the first, second, third, fourth, fifth, sixth, seventh and eighth detection capacitor comb teeth 2-1-3, 2-1-4, 2-1-5, 2-1-1-6, 2-1-2-3, 2-1-2-4, 2-1-2-5, 2-1-2-6 and the drive detection capacitor comb teeth are oppositely inserted to form a detection comb tooth group;

one end of the first tuning fork resonator 2-1-1 is connected to the second output beam 3-1-7 of the first and second differential output micro-levers 3-1), and the other end is connected to the fourth output beam 3-2-7 of the first and second differential output micro-levers 3-2.

The structures of the first, second, third and fourth directional decoupling structures 4-1, 4-2, 4-3 and 4-4 are completely the same; as shown in fig. 5, specifically taking a first directional decoupling structure 4-1 as an example, the first directional decoupling structure 4-1 is composed of a first decoupling anchor point 4-1-1 and a first directional decoupling beam 4-1-2, and is used for ensuring good 8-shaped directional characteristic of the sensor; one end of the first direction decoupling beam 4-1-2 is connected with the first decoupling anchor point 4-1-1.

The electrode and lead wire distribution on the surface of the glass insulating layer 7 in the present invention is shown in FIG. 6.

Wherein the first, second, third and fourth electrodes 6-3-1, 6-3-2, 6-3-3 and 6-3-4 are respectively bonded with the first, second and third four detection capacitance comb teeth 2-1-3, 2-1-1-4, 2-1-1-5 and 2-1-1-6 of the first electrostatic weak coupling resonance structure 2-1 and are connected with the first and second detection signal extraction electrodes 6-1-1 and 6-1-2 through leads;

fifth and sixth electrodes 6-3-5 and 6-3-6 are respectively bonded with first and second drive capacitor comb teeth 2-1-1 and 2-1-1-2 of the first electrostatic weak coupling resonance structure 2-1, and are connected with first and second drive signal extraction electrodes 6-1-3 and 6-1-4 through leads;

seventh and eighth electrodes 6-4-5 and 6-4-6 are respectively bonded with the third and fourth groups of driving capacitance comb teeth 2-1-2-1 and 2-1-2-2 of the first electrostatic weak coupling resonance structure 2-1, and are connected with the third and fourth driving signal leading-out electrodes 6-2-3 and 6-2-4 through leads;

the ninth electrode, the tenth electrode, the eleventh electrode and the twelfth electrode are respectively bonded with the fifth detection capacitor comb teeth 2-1-2-3, 2-1-2-4, 2-1-2-5 and 2-1-2-6 of the first electrostatic weak coupling resonance structure 2-1, the sixth detection capacitor comb teeth 6-4-1, the seventh detection capacitor comb teeth 6-4-3 and 6-4-4, and are connected with the third detection signal extraction electrode 6-2-1 and the fourth detection signal extraction electrode 6-2-2 through leads;

thirteenth and fourteenth electrodes 6-7-5 and 6-7-6 are respectively bonded to fifth and sixth driving capacitance comb teeth 2-2-1-1 and 2-2-1-2 of the second electrostatic weak coupling resonance structure 2-2, and are connected with fifth and sixth driving signal extraction electrodes 6-5-3 and 6-5-4 through leads; fifteenth and sixteenth electrodes 6-8-5 and 6-8-6 are respectively bonded with seventh and eighth driving capacitance comb teeth 2-2-2-1 and 2-2-2-2 of the second electrostatic weak coupling resonance structure 2-2 and are connected with seventh and eighth driving signal leading-out electrodes 6-6-3 and 6-6-4 through leads;

seventeenth, eighteenth, nineteenth and twenty electrodes 6-9-1, 6-9-2, 6-9-4 and 6-9-4 are respectively bonded with the third and fourth tuning fork resonant beams 2-1-2-9 and 2-2-2-9 and are connected with the first and second electrostatic common leading-out electrodes 6-10-1 and 6-10-2 through leads; the twenty-first and twenty-second electrodes 6-11-1 and 6-11-2 are bonded with the common end of the silicon micro-flow meter and are connected with the first and second common end leading-out electrodes 6-12-1 and 6-12-2 through leads.

Twenty-third, twenty-fourth, twenty-fifth and twenty-sixth electrodes 6-7-1, 6-7-2, 6-7-3 and 6-7-4 are respectively bonded with ninth, tenth, eleventh and twelfth detection capacitance comb teeth 2-2-1-3, 2-2-1-4, 2-2-1-5 and 2-2-1-6 of the second electrostatic weak coupling resonance structure 2-2 and are connected with fifth and sixth detection signal leading-out electrodes 6-5-1 and 6-5-2 through leads;

twenty-seventh, twenty-eighth, twenty-ninth, thirty-electrodes 6-8-1, 6-8-2, 6-8-3, 6-8-4 are respectively bonded with thirteenth, fourteen, fifteen, sixteen detection capacitance comb teeth 2-2-3, 2-2-2-4, 2-2-2-5, 2-2-2-6 of the second electrostatic weak coupling resonance structure 2-2, and are connected with seventh and eighth detection signal leading-out electrodes 6-6-1, 6-6-2 through leads.

When the silicon micro-flow meter with adjustable mechanical sensitivity and measurement range is arranged in a horizontal air flow field, fluid acting force caused by friction resistance and pressure difference resistance on the surface of a metal upright post acts on a tuning fork resonant beam of an external tuning fork type resonator of an electrostatic weak coupling resonant structure through a differential output micro-lever, and acting forces generated on the tuning fork resonant beam by an A-type micro-lever structure and a B-type micro-lever structure are opposite in direction, so that the mechanical rigidity of the tuning fork resonant beam is changed, the characteristic vector of the electrostatic weak coupling resonant structure is changed, and finally the difference is generated by the vibration amplitudes of two groups of tuning fork type resonators. The air flow velocity in the horizontal flow field can be obtained by measuring the change of the ratio of the vibration amplitudes of the two groups of tuning fork resonators. The ratio expression of the vibration amplitude of the tuning fork resonator is as follows:

wherein Δ k is the change in mechanical stiffness of the tuning fork resonant beam. k is a radical of_cIs an electrostatically weakly coupled negative stiffness. When alternating current driving voltages with different direct current bias signals are applied to the comb teeth of the driving capacitors of the two groups of tuning fork resonators, electrostatic force is generated on the electrostatic coupling comb tooth group, and electrostatic coupling rigidity of the electrostatic weak coupling resonance structure is changed due to an electrostatic negative rigidity effect, wherein the electrostatic negative rigidity expression is as follows:

wherein N is the number of the electrostatic weak coupling comb teeth, h and l are the width and length of the electrostatic weak coupling comb teeth, e is the distance between the electrostatic weak coupling comb teeth and is an absolute parameter of capacitance, and VT is the difference of bias voltage applied between the electrostatic common leading-out electrode and the common end leading-out electrode. The mechanical sensitivity and the measurement range of the silicon micro-flow velocity meter are both related to the electrostatic coupling rigidity, specifically, when the electrostatic coupling rigidity is increased, the mechanical sensitivity of the silicon micro-flow velocity meter is increased, and the measurement range is reduced; when the electrostatic coupling rigidity is reduced, the mechanical sensitivity of the silicon micro-flow meter is reduced, and the measurement range is increased. Therefore, by changing the difference between the bias voltages applied between the electrostatic common extraction electrode and the common-terminal extraction electrode, the mechanical sensitivity and the measurement range of the silicon micro-flowmeter can be changed.

The technical means disclosed in the invention scheme are not limited to the technical means disclosed in the above embodiments, but also include the technical scheme formed by any combination of the above technical features.