CN106198724A - A kind of novel multistable ultrasound detection sensor - Google Patents
A kind of novel multistable ultrasound detection sensor Download PDFInfo
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- CN106198724A CN106198724A CN201610503035.6A CN201610503035A CN106198724A CN 106198724 A CN106198724 A CN 106198724A CN 201610503035 A CN201610503035 A CN 201610503035A CN 106198724 A CN106198724 A CN 106198724A
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/02—Analysing fluids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
- B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
Abstract
The present invention relates to a kind of novel multistable sensor for ultrasound detection field, including acoustic resistance matching layer, metal electrode, piezoelectric membrane, high pressure resistant insulation layer, cavities seals layer, backing layer and Electromechanical Control circuit board, it is characterized in that described ultrasound detection sensor realizes, by Electromechanical Control circuit, the multistable working method that piezoelectric-type ultrasonic sensing is mutually combined with condenser type ultrasonic sensing on same ultrasonic transducer unit, and each steady operation mode can design according to any supersonic frequency, as being designed according to condenser type low frequency ultrasound sensing and piezoelectric type high frequency ultrasound sensing, take into account the degree of depth and the resolution of ultrasound detection.This multistable ultrasound detection sensor can be flexibly applied to gaseous state, liquid, the supersonic sounding of solid state media medium, impedance matching is simple, volume is little to be easily integrated, can mass production, low cost, has application prospect in fields such as underwater acoustic wave detection, biomedical imaging and industrial ultrasonic Non-Destructive Testings.
Description
Technical field
The present invention relates to a kind of novel multistable ultrasound detection sensor, be mainly used in ultrasound detection and ultra sonic imaging,
Specifically, it is to utilize control circuit to realize piezoelectric-type ultrasonic on same ultrasonic transducer unit to sense ultrasonic with condenser type
The multistable working method that sensing is mutually combined, it is adaptable to underwater acoustic wave detection, biomedical imaging and the lossless inspection of industrial ultrasonic
The fields such as survey.
Background technology
Ultrasound wave is a kind of frequency higher than the elastic wave of the threshold of audibility, has that acoustic energy is concentrated, directivity is good, penetration power is strong, water
The features such as middle propagation distance is remote, at aspects such as medical diagnosis treatment, industrial nondestructive testing, underwater acoustic wave detection, ultrasonic imagings
There is wide application background.Ultrasonic transducer be in ultrasonic frequency range, the signal of telecommunication of alternation is converted into acoustical signal or
Acoustical signal in extraneous sound field is converted into the energy conversion device of the signal of telecommunication by person, according to the difference of electroacoustic transfer principle, ultrasonic
Transducer mainly includes piezoelectric type ultrasonic transducer and capacitive ultrasound transducer etc..
Piezoelectric type ultrasonic transducer be utilize produce after piezoelectric element stress or electric excitation just or inverse piezoelectric effect is come
Realize launching and receiving of ultrasound wave, currently used the most extensive, have that electromechanical conversion efficiency is high, processing technique is simple, skill
Art realizes the advantages such as convenient, cheap and dependable performance, and the acoustic impedance of the acoustic impedance of piezoelectric and solid material is in phase
With on the order of magnitude.But, this transducer also has the most prominent shortcoming, as piezoelectric acoustic impedance is situated between with air-liquid body very greatly
Matter acoustic impedance mismatch, bandwidth is low, and the piezoelectric membrane of high-frequency transducer is difficult to processing, and in adverse circumstances, poor performance even cannot work
Make.The method solving the impedance mismatching between piezoelectric membrane and medium at present is to increase an impedance matching layer in centre, but
Due to matching layer can not process the thinnest and limit the operating frequency of transducer further can not be the highest, and sacrifice the band of transducer
Width, increases complexity and the production cost of structure.
Capacitive ultrasound transducer is to utilize the electrostatic force between capacity plate antenna two battery lead plate and top electrodes (with thin
Film) force balance principle between self structural stress makes.Believe by applying the alternating voltage of certain frequency on electric capacity
Number make thin film occur vibration to produce ultrasound wave, or produce the most ultrasonic when thin film receives ultrasound wave because of acoustic pressure effect
The mechanical vibration of wave frequency, at capacity plate antenna two ends plus certain DC offset voltage, the most now due to thin vibration of membrane
Produce the electric current of change, thus transducer realizes transmitting and the reception of ultrasound wave.Capacitive ultrasound transducer have impedance and gas,
Liquid medium impedance is easily mated, and bandwidth is high, and operating frequency range is big, may be produced that one dimensional line array and two-dimensional surface array, and easily
In integrated with electronic circuit, it is suitable for the features such as adverse circumstances (such as high temperature), but there is also that parasitic capacitance is big, output acoustic pressure is low
Problem.
Owing to MEMS micro-processing technology has the advantage such as higher accuracy and repeated and good concordance, become
A kind of new technological approaches of machined ultrasonic transducers, piezoelectric micromachined ultrasonic transducer based on MEMS processing technology
(Piezoelectric Micromachined Ultrasonic Transducer, pMUT) and capacitance type micromachined ultrasonic change
Study hotspot can be increasingly becoming by device (Capacitive Micromachined Ultrasonic Transducer, cMUT).
The at present both at home and abroad research for pMUT and cMUT is substantially all and rests on stable state single to ultrasonic transducer and set
Meter is analyzed, i.e. or use pMUT and array (Qiu Y, Gigliotti J V, Wallace M, et
al.Piezoelectric micromachined ultrasound transducer(pMUT)arrays for
Integrated sensing, actuation and imaging [J] .Sensors, 2015,15 (4): 8020-8041.),
Use cMUT and array thereof (Zhang R, Zhang W, He C, et al.Underwater Imaging Using a 1 ×
16cMUT Linear Array [J] .Sensors, 2016,16 (3): 312.), the transducer unit working method list after processing
One fixes.Although working sensor frequency is low can realize the longer detection degree of depth, but resolution is relatively low, otherwise, sensor work
Although working frequency height can realize higher resolution, but the detection degree of depth is shorter, it is impossible to accomplish to take into account the detection degree of depth and resolution,
Or use that multiple sensors is integrated to be added device volume and complexity, sensor and array thereof to have pMUT or cMUT intrinsic
Defect.
Accordingly, it would be desirable to study a kind of multistable ultrasound detection sensor, in conjunction with the advantage of pMUT and cMUT, utilize MEMS
Micro-processing technology makes ultrasonic transducer, realizes two kinds of working methods of pMUT and cMUT in a unit, little to realize volume
Be easily integrated array, device flexible design, operating frequency is adjustable, can be widely applied to industry, agricultural, transportation, life doctor
The miniature ultrasonic detection sensor in the fields such as treatment and military affairs is target.Although piezoelectric micromachined ultrasonic transducer can realize bending
Vibration and two kinds of mode of operations of thickness vibration (Hedegaard T, Pedersen T, Thomsen E V, et al.Screen
printed thick film based pMUT arrays[C]//2008IEEE Ultrasonics Symposium.IEEE,
2008:2126-2129.), but a transducer unit can only select one of which pattern to work, it is impossible to selectivity switch, tool
There is the shortcoming that piezoelectric type ultrasonic transducer is intrinsic, and two kinds of mode of operations add the difficulty that device resistance is mated, further shadow
Ring the performance of sensor.
Summary of the invention
The present invention is directed to deficiency present in above-mentioned prior art, propose a kind of novel multistable on its basis
Ultrasound detection sensor, utilizes control circuit can realize piezoelectric-type ultrasonic sensing and electric capacity on same ultrasonic transducer unit
The multistable working method that formula ultrasonic sensing is mutually combined, has taken into account the degree of depth and the resolution of ultrasound detection, operation principle such as Fig. 1
Shown in.Technical scheme is as follows:
A kind of novel multistable ultrasound detection sensor, including acoustic resistance matching layer, metal electrode, piezoelectric membrane, resistance to height
Pressure insulating barrier, cavities seals layer, backing layer and Electromechanical Control circuit board.Steady by piezoelectric type ultrasonic sensing and condenser type ultrasonic sensing
The difference of state operating frequency, overall structure has two kinds of forms, as shown in Figures 2 and 3.
Described multistable ultrasound detection sensor, according to structure as shown in Figure 2, it is characterised in that: described multistable surpasses
Sound detection sensor can be according to pMUT and cMUT two ways work in combination, and pMUT working method is come real by overlaminate conductive film
Existing, this piezoelectric membrane upper/lower terminal is metal electrode, is acoustic resistance matching layer above apex electrode, is upper strata below bottom electrode
Cavities seals layer；CMUT working method is realized by laminated conductive film and lower floor's cavities seals layer, on laminated conductive film,
Lower two ends are metal electrode, are high pressure resistant insulation layer above apex electrode, are lower floor's cavities seals layer below bottom electrode, this sky
It is high pressure resistant insulation layer below cavity layer, is metal electrode below this insulating barrier, be backing layer below metal electrode, at backing layer
It is Electromechanical Control circuit board below.
Described multistable ultrasound detection sensor as shown in Figure 2, the operation principle of its ultrasound detection is:
(1) under pMUT working method, A, B, C, D metal electrode through hole lead-in wire is concatenated together as power supply ground wire,
If applying appropriately sized high-frequency voltage signal on E metal electrode, then due to inverse piezoelectric effect, piezoelectric membrane is shaken
Move and launch ultrasound wave, if piezoelectric membrane receives ultrasound wave, can be according to corresponding frequency vibration, due to direct piezoelectric effect, thin
Vibration of membrane by produce corresponding frequencies voltage and amplified after detected, laminated conductive film friction during this；
(2) under cMUT working method, D, E metal electrode through hole lead-in wire is concatenated together, at upper strata cavity upper and lower two
The voltage of sufficient intensity is applied, owing to the electrostatic force between two metal electrode boards is more than structure between termination electrode (composition capacity plate antenna)
Stress, overlaminate conductive film and laminated conductive film are pulled together as new piezoelectric membrane (Fig. 4), using A metal electrode as
Power supply ground wire, if apply appropriately sized high-frequency electrical between lower floor's cavities seals layer upper/lower terminal electrode (composition capacity plate antenna)
Pressure signal, new piezoelectric membrane produces ultrasound wave and launches due to the electrostatic force of alternation, if new piezoelectric membrane receives
To ultrasound wave, thin film produces the vibration of corresponding frequencies due to the acoustic pressure effect of certain frequency, now at lower floor's cavities seals layer
A certain size DC offset voltage a certain size electric capacity in parallel is applied, then due to piezoelectric membrane between upper/lower terminal electrode
Vibration finally produce and can survey electric current accordingly, it is achieved the reception of ultrasound wave and detection.
Described multistable ultrasound detection sensor, according to structure as shown in Figure 3, it is characterised in that: described multistable surpasses
Sound detection sensor can be according to pMUT and cMUT two ways work in combination, and pMUT working method is come real by laminated conductive film
Existing, this piezoelectric membrane upper/lower terminal is metal electrode, and apex electrode upper end is high pressure resistant insulation layer, and this insulating layer is upper
Layer cavities seals layer, is lower floor's cavities seals layer below bottom electrode, is backing layer, below backing layer is below this cavity layer
Electromechanical Control circuit board；CMUT working method is realized by overlaminate conductive film and upper strata cavities seals layer, and upper strata piezoelectricity is thin
Film upper/lower terminal is metal electrode, is acoustic impedance matching layer above apex electrode, is lower floor's cavities seals below bottom electrode
Layer, lower floor's cavities seals layer upper/lower terminal is respectively overlaminate conductive film bottom electrode and high pressure resistant insulation layer.
Described multistable ultrasound detection sensor as shown in Figure 3, the operation principle of its ultrasound detection is:
(1) under cMUT working method, A, B metal electrode through hole lead-in wire is concatenated together as power supply ground wire, if
Appropriately sized high-frequency voltage signal, overlaminate conductive film is applied between upper strata cavity upper/lower terminal electrode (composition capacity plate antenna)
Produce ultrasound wave due to the electrostatic force of alternation and launch, if overlaminate conductive film receives ultrasound wave, thin film by
The vibration of corresponding frequencies is produced, now between the cavities seals layer upper/lower terminal electrode of upper strata in the acoustic pressure effect of certain frequency
Apply a certain size DC offset voltage a certain size electric capacity in parallel, then finally produce phase due to the vibration of piezoelectric membrane
The electric current surveyed answered, it is achieved the reception of ultrasound wave and detection, laminated conductive film friction during this.
(2) under pMUT working method, the electricity of sufficient intensity is applied at B, C metal electrode two ends (composition capacity plate antenna)
Pressure, owing to the electrostatic force between two metal electrode boards is more than structural stress, overlaminate conductive film is pull-in on laminated conductive film
Together as new piezoelectric membrane (Fig. 5), using A metal electrode as power supply ground wire, if at laminated conductive film upper/lower terminal electrode
Between apply appropriately sized high-frequency voltage signal, then overlaminate conductive film is equivalent to load and acts on laminated conductive film upper end,
Owing to inverse piezoelectric effect makes new piezoelectric membrane occur vibration to launch ultrasound wave, if new piezoelectric membrane receives ultrasound wave, can
According to corresponding frequency vibration, due to direct piezoelectric effect, thin vibration of membrane by produce corresponding frequencies voltage and amplified after
Detected.
When described multistable ultrasound detection sensor (Fig. 2, Fig. 3) works according to pMUT mode, its first-order bending vibration
Frequency may determine that into:Wherein, αplFor the single order vibration factor under pMUT mode, t is that piezoelectricity is thin
The thickness of film, a is the length of side (regular polygon) or radius (circular), the Y of piezoelectric membrane0For the Young's modulus of piezoelectric membrane, v is pressure
The Poisson's ratio of conductive film.
When described multistable ultrasound detection sensor (Fig. 2, Fig. 3) works according to cMUT pattern, its first-order bending vibration
Frequency may determine that into:Wherein, αc1For the single order vibration factor under cMUT mode, t is that piezoelectricity is thin
The thickness of film, a is the length of side (regular polygon) or radius (circular), the Y of piezoelectric membrane0For the Young's modulus of piezoelectric membrane, v is pressure
The Poisson's ratio of conductive film.Collapse voltage during the capacity plate antenna generation adhesive being made up of cavities seals layer upper/lower terminal electrode is:Wherein, k is the coefficient of elasticity of piezoelectric membrane, d0For cavity layer elemental height, ε0Normal for the dielectric in vacuum
Number, A is the surface area of piezoelectric membrane.Relation between Displacement-deformation and the driving voltage of applying of piezoelectric membrane is:WhenTime capacity plate antenna generation adhesive.
Described multistable ultrasound detection sensor, Electromechanical Control circuit board is used for controlling the work of ultrasound detection sensor
Mode and ultrasonic transducer transmitting and receiving mode, can be one or more layers circuit board, it is possible to use printed circuit board or
Flexible PCB, circuit board can use Copper Foil or other conductive materials to replace.Additionally, circuit board can be fixed on backing layer table
The surface of face, surface of metal electrode or piezoelectric membrane.
Described multistable ultrasound detection sensor, high pressure resistant insulation layer is not particularly limited, as long as can play at electric capacity
Prevent short circuit during pole plate generation adhesive and avoid being broken down by high-voltage, the material such as such as polyvinyl fluoride, polyethylene, polylactic acid.
Described multistable ultrasound detection sensor, piezoelectric membrane is one layer or is formed by multiple-layer stacked, and piezoelectric selects
From piezoelectric ceramics, piezoelectric monocrystal, piezo-electricity composite material or piezopolymer etc..Wherein, piezoelectric ceramics can be PZT, AlN, ZnO
Or other piezoelectrics.
Described multistable ultrasound detection sensor, acoustic impedance matching layer is one layer or is formed by multiple-layer stacked, and this is ultrasonic
The material of acoustic impedance matching layer is not specifically limited by detection sensor, and the thickness of acoustic impedance matching layer is by the acoustics of transducer designs
Require to be determined.
Described multistable ultrasound detection sensor, its construction profile can be circular, square or polygon plane is first
Part, the size of transducer is determined by operating frequency, and the surface area of transducer is the biggest, and thickness is the thinnest, then the single order of transducer is humorous
Vibration frequency is the lowest, otherwise then one class resonant frequency is the highest.Transducer can be according to the different steady operation frequency of application demand design
The sensor of combination, supersonic frequency under supersonic frequency is 5MHz, cMUT steady operation mode under such as pMUT steady operation mode
For the ultrasound detection sensor (Fig. 2) of 20MHz, or under cMUT steady operation mode, supersonic frequency is 5MHz, pMUT stable state work
Make the ultrasound detection sensor (Fig. 3) that supersonic frequency under mode is 20MHz.In some embodiments, described ultrasonic inspection
Surveying sensor can be the array ultrasound transducer such as 1D, 2D, and wherein, 1D array energy transducer refers to that transducer unit is along length side
To linear array, 2D array energy transducer refers to that transducer unit is along length and width direction linear array.
Described multistable ultrasound detection sensor, sensor can be single element transducer or be pressed with one heart by multiple array elements
The ultrasonic transducer that the mode of circle arranges.
The multistable ultrasound detection sensor realized by the design has that volume little is easily integrated, low in energy consumption, performance can
Lean on, operating frequency is adjustable, ultrasound detection mode can the advantage such as free switching, by different outer package forms, this device is permissible
Ultrasound detection is carried out at vacuum, air, the multiple varying environment such as under water.Compared with the existing methods, present invention design is multistable
State ultrasound detection sensor has the following characteristics that
(1) designed piezoelectric micromachined ultrasonic transducer (pMUT) and micro-electric capacity ultrasonic transducer by suitable structure
(cMUT) two kinds of transducer working method combines, and breaks through what traditional devices can only work with single steady state way
Limitation, it is achieved multistable ultrasound detection；
(2) by adjusting the structural parameters of transducer, the multistable ultrasound detection that any supersonic frequency is combined can be realized,
Such as can be sensed by Electromechanical Control circuit realiration low frequency ultrasound sensing and high frequency ultrasound, take into account the degree of depth of ultrasound detection with
Resolution, structure flexible design, application prospect is extensive；
(3) this device has the advantage of pMUT and cMUT concurrently, can be flexibly applied to gaseous state, liquid, solid state media medium super
Acoustic detection, impedance matching is simple, in this embodiment it is not even necessary to matching layer；
(4) this device uses micro-nano technology fabrication techniques, and volume is little, low in energy consumption, beneficially the mass production of device, device
Part production cost is low, and consistency of performance is good；
(5) this device can be widely applied to underwater acoustic wave detection, biomedical imaging and industrial ultrasonic Non-Destructive Testing etc.
Multiple fields
Accompanying drawing explanation
Fig. 1: multistable ultrasound detection sensor operating principles figure；
Fig. 2: pMUT steady frequency be 5MHz, cMUT steady frequency be that the ultrasound detection sensors sides structure of 20MHz is shown
It is intended to (structure one)；
Fig. 3: cMUT steady frequency be 5MHz, pMUT steady frequency be that the ultrasound detection sensors sides structure of 20MHz is shown
It is intended to (structure two)；
Sensor shown in Fig. 4: structure one is schematic diagram when two-layer piezoelectric membrane generation adhesive；
Sensor shown in Fig. 5: structure two is schematic diagram when two-layer piezoelectric membrane generation adhesive.
Label in accompanying drawing is respectively as follows: 1, Electromechanical Control circuit board, and 2, backing layer, 3, high pressure resistant insulation layer, 4, metal electricity
Pole, 5, cavities seals layer, 6, piezoelectric membrane, 7, acoustic impedance matching layer.
Detailed description of the invention
The present invention provides a kind of novel multistable ultrasound detection sensor, including Electromechanical Control circuit board 1, backing layer 2,
High pressure resistant insulation layer 3, metal electrode 4, cavities seals layer 5, piezoelectric membrane 6 and acoustic impedance matching layer 7.Below in conjunction with the accompanying drawings and real
Execute example so that the specific implementation method of the present invention to be described.
The one novel multistable ultrasound detection sensor that the present embodiment provides, its concrete technology implementation thinking: use
Electromechanical Control circuit controls the working method of multistable ultrasound detection sensor, according to practical application request at pMUT and cMUT two
Switching between the mode of kind, the mode of operation further according to required transducer selects to launch or receive ultrasound wave, as shown in Figure 1.
The present embodiment provides the multistable ultrasound detection sensor of two kinds of different structures: pMUT steady operation supersonic frequency is
5MHz, cMUT steady operation supersonic frequency is the ultrasound detection sensor of 20MHz, and texture edge is as shown in Figure 2；CMUT stable state work
As supersonic frequency be 5MHz, pMUT steady operation supersonic frequency be the ultrasound detection sensor of 20MHz, texture edge such as Fig. 3 institute
Show.
In multistable ultrasound detection sensor (Fig. 2) shown in structure one, the ultrasonic transducer under pMUT mode is main
Including five layers, i.e. overlaminate conductive film 6, overlaminate conductive film top and bottom metal electrode 4, top metal electrode upper strata are sound
Impedance matching layer 7, bottom metal electrode lower floor are upper strata cavities seals layer 5, remainder for working sensor state without shadow
Ring, can be not considered.When transducer works with emission mode, apply the biggest between the metal electrode of overlaminate conductive film two ends
Little high frequency excitation voltage, when transducer works in a receiving mode, between the metal electrode of overlaminate conductive film two ends, output is super
The voltage signal of sound wave corresponding frequencies.Ultrasonic transducer under cMUT mode needs first at cavities seals layer two ends, upper strata metal electrode
The voltage applying sufficient intensity between (C, D) makes overlaminate conductive film and laminated conductive film generation adhesive (under collapsed mode
Transducer side structure is as shown in Figure 4), metal electrode E and metal electrode D cascades, the upper end of laminated conductive film apex electrode C
For high pressure resistant insulation layer 3, the lower end of laminated conductive film bottom electrode B is lower floor's cavities seals layer, this cavities seals layer lower end
For high pressure resistant insulation layer, insulating barrier covers on metal electrode A, and the lower end of metal electrode A is backing layer 2, and it is deposited on
Above Electromechanical Control circuit board 1.When transducer works with emission mode, at lower floor's cavities seals layer two ends metal electrode
Appropriately sized high frequency excitation voltage is applied between (A, B), when transducer works in a receiving mode, defeated between metal electrode A and B
Go out the current signal of ultrasound wave corresponding frequencies.
In multistable ultrasound detection sensor (Fig. 3) shown in structure two, the ultrasonic transducer under cMUT mode is main
Including six layers, i.e. upper strata cavities seals layer 5, this cavities seals layer top be metal electrode 4, the upper end of metal electrode C be upper strata
Piezoelectric membrane 6, the upper end of this piezoelectric membrane is acoustic impedance matching layer 7, and high pressure resistant insulation layer 3 is at upper strata cavities seals layer and metal
In the middle of electrode B, remainder, can be not considered without impact for working sensor state.When transducer works with emission mode
Time, between the metal electrode of cavities seals layer two ends, upper strata, apply appropriately sized high frequency excitation voltage, when transducer is to receive mould
During formula work, the current signal of output ultrasonic wave corresponding frequencies between metal electrode B and C.Ultrasonic transducer under pMUT pattern
Need the voltage that first apply sufficient intensity between cavities seals layer two ends, upper strata metal electrode (B, C) make overlaminate conductive film with under
Lamination conductive film generation adhesive (the transducer side structure under collapsed mode is as shown in Figure 5), laminated conductive film top is gold
Belonging to electrode B, the bottom of laminated conductive film is high pressure resistant insulation layer, and this insulating barrier covers in the upper end of metal electrode A, metal electricity
The lower end of pole A is backing layer 2, and it is deposited on the upper end of Electromechanical Control circuit board 1.When transducer works with emission mode,
Appropriately sized high frequency excitation voltage is applied, when transducer is to receive mould between lower floor's cavities seals layer two ends metal electrode (A, B)
During formula work, the voltage signal of output ultrasonic wave corresponding frequencies between metal electrode A and B.
It should be noted that every layer of material may each be one layer or has multiple-layer stacked to form, such as acoustic impedance matching layer
Can have one or more layers, piezoelectric membrane can also have one or more layers.The position of Electromechanical Control circuit board is not limited at backing
The bottom of layer, such as, can be disposed at the side of piezoelectric membrane, can add control transducer and launch and connect in circuit board
The special integrated electronic circuit chip (ASIC) received.
Piezoelectric membrane described in the present embodiment, its material can be piezoelectric ceramics, piezoelectric monocrystal, piezo-electricity composite material or
Piezopolymer etc..Wherein, piezoelectric ceramics can be PZT, AlN, ZnO or other piezoelectrics.Piezoelectric membrane profile is permissible
For circular, square or polygon plane element.
In an embodiment, high pressure resistant insulation layer is not particularly limited, as long as can play when capacitor plate generation adhesive anti-
Only short circuit avoid being broken down by high-voltage, the material such as such as polyvinyl fluoride, polyethylene, polylactic acid.
In the present embodiment, the selection of device parameters can be according to the requirement of operating frequency required in reality application and processing work
The level of skill sets, and operating frequency the highest then transducer unit overall dimensions is the least.Such as, if requiring, transducer is at pMUT mould
Operating frequency under formula is about 3.5MHz (designing according to structure one), and piezoelectric membrane selects AlN material, the then limit of film square
Long and thickness can be respectively as follows: 50 μm and 0.5 μm, 70 μm and 1 μm, or 85 μm and 1.5 μm.
In sum, two kinds of for pMUT and cMUT ultrasonic transducer working method is combined by the present invention, real
Existing multistable ultrasound detection, can carry out low frequency ultrasound sensing by Electromechanical Control circuit and high frequency ultrasound senses, take into account super
The degree of depth of sound detection and resolution, can be widely applied to the fields such as industry, medical treatment, military affairs, agricultural.
Above example, only in order to technical scheme to be described, describes all of details the most in detail, does not limits
The present invention processed is described detailed description of the invention.Obviously, a lot of amendment and modification can be made according to the content of this specification.If
These amendments and modification for the present invention belong within the scope of the claims in the present invention and equivalent technologies thereof, then the present invention is also
It is intended to encompass these to change and including modification.
Claims (9)
1. a novel multistable ultrasound detection sensor, including acoustic resistance matching layer, metal electrode, piezoelectric membrane, high pressure resistant
Insulating barrier, cavities seals layer, backing layer and Electromechanical Control circuit board, it is characterised in that sensor is at same ultrasonic transducer list
Realize the multistable working method that piezoelectric-type ultrasonic sensing is mutually combined with condenser type ultrasonic sensing in unit, utilize Electromechanical Control electricity
Road can realize working method switching, and every kind of steady state way is launched according to respective operating frequency or receives ultrasound wave.
Multistable ultrasound detection sensor the most according to claim 1, it is characterised in that: described sensor respectively according to
First-order bending vibration frequency during the work of pMUT and cMUT steady state way is:
Wherein, αp1And αc1It is respectively the single order vibration factor under pMUT and cMUT pattern, tpAnd tcIt is respectively under pMUT and cMUT pattern
The thickness of piezoelectric membrane, a is the length of side (regular polygon) or radius (circular), the Y of piezoelectric membrane0Young mould for piezoelectric membrane
Amount, v is the Poisson's ratio of piezoelectric membrane.
Multistable ultrasound detection sensor the most according to claim 2, it is characterised in that: described ultrasound detection sensor
Supersonic frequency under bistable state or multistable configuration, and every kind of stable state can be combined into by pMUT and cMUT working method can arbitrarily select
Design.
Multistable ultrasound detection sensor the most according to claim 3, it is characterised in that: described multistable ultrasound detection
Sensor can carry out low frequency ultrasound sensing according to pMUT mode and cMUT mode carries out high frequency ultrasound sensing, or according to cMUT side
Formula carries out low frequency ultrasound sensing and pMUT mode carries out high frequency ultrasound two kinds of structures of sensing and is designed, and takes into account the deep of ultrasound detection
Degree and resolution.
Multistable ultrasound detection sensor the most according to claim 1, it is characterised in that: described acoustic impedance matching layer,
Piezoelectric membrane and Electromechanical Control circuit board can be all one layer or be formed by multiple-layer stacked.
Multistable ultrasound detection sensor the most according to claim 1, it is characterised in that: described piezoelectric film material choosing
From piezoelectric ceramics, piezoelectric monocrystal, piezo-electricity composite material or piezopolymer etc..
Multistable ultrasound detection sensor the most according to claim 1, it is characterised in that: described high pressure resistant insulation layer does not has
There is concrete restriction, prevent short circuit and avoid being broken down by high-voltage as long as can play when capacitor plate generation adhesive, such as poly-fluorine
The materials such as ethylene, polyethylene, polylactic acid.
Multistable ultrasound detection sensor the most according to claim 1, it is characterised in that: described metal electrode does not have
Body limits, and can be the metal materials such as aluminum, silver, platinum.
Multistable ultrasound detection sensor the most according to claim 1, it is characterised in that: described ultrasound detection sensor
Including one dimensional line array (1D), two-dimensional surface array (2D) array energy transducer of ultrasonic transducer unit, or it it is single array element sensing
Device, the sensor arranged by the mode of concentric ring by multiple array elements, it is achieved two-dimentional or three-dimensional realtime imaging.
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