CN1143184A - Sensor element and particle sensor - Google Patents
Sensor element and particle sensor Download PDFInfo
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- CN1143184A CN1143184A CN 95115106 CN95115106A CN1143184A CN 1143184 A CN1143184 A CN 1143184A CN 95115106 CN95115106 CN 95115106 CN 95115106 A CN95115106 A CN 95115106A CN 1143184 A CN1143184 A CN 1143184A
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Abstract
A sensor element for detecting solid particles in a fluid includes: a detecting unit including a piezoelectric film consisting essentially of a ceramic material, a first electrode coated onto at least a portion of the outer surface of the piezoelectric film, and a second electrode coated onto at least a portion of the inner surface of the piezoelectric film; a vibrating portion consisting essentially of a second ceramic material, the detecting unit being placed on the vibrating portion, so that the second electrode is coated onto at least a portion of the vibrating portion, a fixed portion for fixing the vibrating portion so that the vibrating portion may vibrate. At least one of the detecting unit and the vibrating portion contacts with a solid particle in the fluid so that the piezoelectric film converts the vibration into an electric signal.
Description
The present invention relates to sensor element and particle sensor with sensor element.Sensor element comprises the piezoelectric film of the particle in the test fluid.
When the fluid as liquid or gas comprises solid particle, need to detect the particle of existence sometimes.Particularly when the performance of the particle convection cell of not wishing to exist particle, existence in the fluid counteracts, detect particle and just become extremely important.
For example, the engine of internal combustion engine such as motor car engine or heavy-duty machinery uses gasoline or engine solar oil as its power source.These internal combustion engines utilize lubricant to reduce on the surface of revolution of engine etc. or the slidingsurface or suchlike friction is dragged and scraped or wear and tear.In internal combustion engine, the such particle of metal particle that produces such as wearing and tearing may mix mutually with lubricant, has therefore quickened the wearing and tearing of surface of revolution or slidingsurface.Particle in the lubricant is generally removed by filtrator such as oil strainer.Can monitor the state of lubricant in more detail by the particle in the detection lubricant.
Application of the present invention is not limited to internal combustion engine.Hydraulic fluid is used for the power in the machinery transmitting device, as hydrostatic transmission, hydraulic actuator, Hydrauservo System etc.The state of control fluid is very important, and it comprises particle and/or the viscosity of fluid etc. of control in the fluid.
For monitoring the air-polluting degree, the existence of suspended particle and concentration also are very important.For example, monitor that the suspended particle from the smog of factory's discharging is very important.It should be noted that fluid can be gas or liquid, and these media needn't flow.
A kind of method of routine that is used for the particle of test fluid is that a pair of electrode that leaves certain intervals is set, and the resistance between the monitoring electrode.Utilize this method to detect metallic particles, because when metallic particles contacts with two electrodes, the resistance between the electrode descends.Yet this method can not detect the particle less than interval between the electrode, can not detect the particle of electrical isolation.
In another approach, in detecting unit, produce a magnetic field, so that detect amount such as the such particle of the metallic particles of accumulation by electromagnet etc.Yet this method can not detect does not have ferromagnetic particle, so its precision is restricted.
In the third method, the amount of the particle in the fluid is relevant with the optical transmission rate, so that the amount of the particle in the test fluid.Yet the transmissivity of fluid is always inconstant; The general who has surrendered changes the optical transmission rate under the fluid quality; And the dust on the window that window that incident light sees through or detected light see through has great influence to error.These effects limit the serviceable life of sensor.
The present invention is intended to address the above problem, and a kind of have splendid accuracy of detection and serviceable life, sensor element and particle sensor that cost is low are provided.
One aspect of the present invention provides the sensor element of the solid particle that has nothing to do in a kind of test fluid, sensor element comprises the oscillating component with enough little quality, be used for the collision with solid particle is responded, and comprise the equipment that is used for the vibration of oscillating component is transformed into electric signal, so that detect this vibration.
According to the present invention, this equipment preferably has at least one device that is used to change, this device is to choose from comprise the group with lower device: piezo-electric device, electromagnetic induction device, the electric capacity modifier, light is transmitted into described oscillating component, and detect receives the device that the light of the part of light changes, and the change of the resistance that will cause owing to the stress in the semiconductor is transformed into the device of electric signal.
Another aspect of the present invention provides a kind of sensor element, comprise: detecting unit, comprise the piezoelectric film that constitutes by first stupalith substantially, be coated in first electrode at least a portion of outside surface of piezoelectric film and be coated in second electrode at least a portion of inside surface of piezoelectric film; The basic oscillating component that constitutes by second stupalith, detecting unit is positioned on the oscillating component, and therefore second electrode is coated at least a portion of oscillating component; And the fixed part that is used for fixing oscillating component, so oscillating component can vibrate; Wherein when bump detecting unit of the solid particle in the fluid and/or oscillating component, oscillating component vibrates, and described piezoelectric film is transformed into electric signal with vibration.
Oscillating component and fixed part can be the ceramic substrate parts with single chip architecture, and described ceramic substrate has been preferably formed as resonator cavity, and therefore described oscillating component has the very little sheet shape of thickness.
First stupalith preferably includes a kind of material of selecting at least from following group, this group comprises: lead zirconates, lead magnesium niobate, lead niobate nickel, lead niobate zinc, lead niobate manganese, lead stannate antimony, lead titanates, lead tungstate magnesium, lead niobate cobalt and barium titanate.Preferably a kind of oil of fluid is as lubricating oil and hydraulic oil.Preferably from 1 to 100 micron of the thickness range of piezoelectric film, preferably from 1 to 100 micron of the thickness range of oscillating component.
Oscillating component preferably includes stable zirconia.
A third aspect of the present invention provides a kind of particle sensor, comprise (a) sensor element, comprise: detecting unit, comprise the piezoelectric film that constitutes by first stupalith substantially, be coated in first electrode at least a portion of outside surface of piezoelectric film and be coated in second electrode at least a portion of inside surface of piezoelectric film; The basic oscillating component that constitutes by second stupalith, detecting unit is positioned on the oscillating component, and therefore second electrode is coated at least a portion of oscillating component; And the fixed part that is used for fixing oscillating component, so oscillating component can vibrate; Wherein when bump detecting unit of the solid particle in the fluid and/or oscillating component, oscillating component vibrates, and described piezoelectric film is transformed into electric signal with vibration; And the over cap that (b) covers detecting unit.
A fourth aspect of the present invention provides the method for the solid particle in a kind of test fluid, and wherein sensor element is with respect to the fluid motion that is verified, and solid particle and oscillating component irrelevant in the therefore feasible fluid that is verified collide.
In sensor element of the present invention, when the solid particle in the fluid contacts with detecting unit or oscillating component, detecting unit or oscillating component vibration.The piezoelectric film of detecting unit is transformed into electric signal with vibration, and the output of the electrode between piezoelectric film electric signal.Particle sensor with sensor element detects particle by the output from these electrodes.It should be noted that particle contacts with detecting unit or oscillating component comprises particle and detecting unit or oscillating component collision.Sensor element of the present invention can be measured the viscosity of fluid by self-excitation.
Fig. 1 is the cut-open view of sensor element of the present invention, i.e. the view of cutting open along the A-A line of Fig. 3;
Fig. 2 is the skeleton view of an example of sensor element of the present invention.
Fig. 3 is the top view of an example of sensor element of the present invention.
Fig. 4 is the cut-open view of particle sensor of the present invention.
Fig. 5 is the cut-open view of sensor element of the present invention.
Fig. 6 is an embodiment of sensor element.Fig. 6 (a) is the top view of an example of sensor element of the present invention.Fig. 6 (b) is the cut-open view along the B-B line.
Fig. 1 is the cut-open view of sensor element 10 of the present invention.Fig. 2 is the skeleton view of the sensor element 10 of Fig. 1, for convenience of description for the purpose of, the part of the part of piezoelectric film 22 and top electrode 24 has been omitted.Fig. 3 is the top view of the sensor element 10 of Fig. 1.
In the present invention, needn't be as the entire circumference that supports oscillating component as shown in Figure 1 by fixed part.Shown in Fig. 6 (a) and Fig. 6 (b), can adopt so-called cantilever design to support an only end on every side of oscillating component 74 by fixed part 76.At least a portion that supports a part of oscillating component or oscillating component by fixed part is possible on every side.
When sensor element 10 detected particle, oscillating component 14 had been with detecting unit 20 vertical vibrations, promptly vibrated towards detecting unit 20 or towards the direction of resonator cavity 18.Preferably oscillating component 14 has the shape of sheet, because this shape is suitable for vibration.In this case, the preferable range of the thickness of sheet is 1-100 μ m, and 3-50 μ m is better, preferably 5-20 μ m.Sheet is thicker to make sensitivity descend, and thinner thickness makes physical strength descend.
Oscillating component 14 is preferably made by resistant to elevated temperatures material, so that prevent oscillating component because heat causes mis-behave.This is because detecting unit 20 may directly be put on the oscillating component 14, and is middle without any material (for example organic bond of non-refractory).In this case, when forming piezoelectric film 22, oscillating component 14 should not be damaged yet.When sensor element was used for lubricant as oil, oscillating component contacted with organic solvent in being included in lubricant sometimes, or lubricant becomes acidity or alkalescence.Therefore oscillating component is preferably made by the material of stable chemical performance.
Oscillating component 14 is preferably made by electrical insulator because cover at least a portion oscillating component 14 second electrode, all conduct electricity with lead-in wire, lead terminal and similar portions that first electrode links to each other with second electrode.Therefore, oscillating component 14 can be made by the metal with good high-temperature characteristic, its outside with pottery for example glass cover.Preferably oscillating component 14 is made by pottery.For example, stable zirconia, aluminium oxide, magnesium oxide, mullite, aluminium nitride, silicon nitride, glass or similar material are applicable to oscillating component.Preferred stable zirconia, even because oscillating component is thin, it also has very high physical strength and very high toughness, and with difficult generation chemical reactions such as piezoelectric film and electrode.
Stable zirconia comprises stable zirconium dioxide and partially stabilized zirconium dioxide.Stable zirconia does not experience phase transformation, because it has crystal structure, and cubic system for example.On the other hand, zirconia is experiencing phase transformation under about 1000 ℃ between monoclinic structure and tetragonal structure.This phase transformation will produce slight crack.Stable zirconia comprises the calcium oxide, magnesium oxide, yttria, scandium oxide, ytterbium oxide, cerium oxide of 1-30mol% or such as the such stabilizing agent of rare-earth oxide.Stabilizing agent preferably includes yttria, so that strengthen the physical strength of oscillating component.The amount that is included in the yttria in the stabilizing agent is preferably 1.5-6mol%, and 2-4mol% is then better.In addition, principal crystalline phase can belong to the mixing of tetragonal crystal system or tetragonal crystal system and cubic system.
The pottery that constitutes oscillating component 14 preferably includes the monox of 0.5-5wt%, and 1-3wt% is then better, because monox overreaction between oscillating component 14 and the detecting unit 20 when having prevented to form detecting unit 20 by thermal treatment.
When oscillating component 14 was made by pottery, it was made of many crystal grain.The mean diameter of crystal grain is 0.05-2 μ m preferably, and 0.1-1 μ m is then better.
Fixed part 16 is at least a portion oscillating component 14 fixedly, or around at least a portion of oscillating component 14.Under mode shown in Figure 1, fixed part 16 is preferably made by pottery.The stupalith of fixed part 16 can be with oscillating component identical, or can be different.Stable zirconia, mullite, aluminium oxide, magnesium oxide, aluminium nitride, silicon nitride, glass or similar material are not only applicable to oscillating component 14, and are applicable to the pottery that constitutes fixed part.
The shape of closed resonator 18 is unrestricted.The level of resonator cavity or vertical cross-section can be for example circular, oval, comprise and rectangle and leg-of-mutton polygon some shape in these shapes combined.Yet, when shape is polygon or analogous shape, preferably with rounding of angle, so that remove sharp-pointed edge.
Detecting unit 20 comprises piezoelectric film 22, covers first electrode 24 of at least a portion outside surface 22s of piezoelectric film 22, and second electrode 26 that covers at least a portion inside surface 22t of piezoelectric film 22.Second electrode 26 covers at least a portion outside surface 14s of oscillating component 14.
The preferable range of the thickness of piezoelectric film is 1-100 μ m, and 5-50 μ m is better, preferably 5-30 μ m.Thicker thickness makes sensitivity descend, and thinner thickness makes reliability decrease.
Piezoelectric ceramics is applicable to piezoelectric film.Piezoelectric film can be the pottery with electrostriction phenomena, also can be the pottery with ferroelectricity.In addition, the material and the material of handling that do not need to polarize that needs polarization to handle all can be used to achieve the goal.
The pottery that is used for piezoelectric film can comprise for example lead zirconates, lead magnesium niobate, lead niobate nickel, lead niobate zinc, lead niobate manganese, lead stannate antimony, lead titanates, barium titanate, or their a kind of combination.Pottery can comprise a kind of compound in these compounds that are not less than 50wt% as principal ingredient.Can preferably adopt the pottery that comprises lead zirconates.In addition, the oxide of lanthanum, calcium, strontium, molybdenum, tungsten, barium, niobium, zinc, nickel, manganese etc.; Their a kind of combination; Or other compound is applicable to adding in the above-mentioned pottery.For example, preferably adopt a kind of composition that comprises in lead magnesium niobate, lead zirconates and the lead titanates, and further comprise the pottery of lanthanum and strontium as principal ingredient.
Piezoelectric film can be densification or loose.When piezoelectric film is when loosening, porosity is preferably below 40% or 40%.
Piezoelectric film can comprise one deck or can be to comprise two-layer at least stack membrane.When piezoelectric film was a stack membrane, each layer can be horizontal positioned or vertical the placement.
Detecting unit not only can also be placed on a side of oscillating component, and can be placed on the both sides of oscillating component.
In Fig. 3, first electrode 24 and second electrode 26 by go between 28 and lead-in wire 30 will export dististyle 32 and dististyle 34 to from the electric signal of piezoelectric film 22.First electrode 24 links to each other with lead-in wire 28 by coupling part 25.Coupling part 25 contacts with piezoelectric film 22, and does not contact with lead-in wire 30 with second electrode 26.It should be noted that can form second electrode 26, lead-in wire 28, lead-in wire 30, dististyle 32 and dististyle 34 simultaneously by film forming method, this will illustrate afterwards.
In first electrode and second electrode each has suitable thickness by its purposes decision.Yet, 0.1-50 μ m preferably.
Best first electrode at room temperature solidifies, and is made of conducting metal.For example, can adopt metals such as aluminium, titanium, chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead; Perhaps their a kind of alloy.Much less, first electrode can comprise these elements that occur in any combination.Belong to a kind of metal of platinum family such as platinum, rhodium, palladium, or comprise a kind of alloy of these metals,, be suitable as the principal ingredient of electrode material as silver-platinum or platinum-palladium.Preferably use copper, silver and golden, because they are very durable.
Second electrode preferably is made of a kind of simple material, and this material comprises and has high-melting point metal, as platinum, ruthenium, rhodium, palladium, iridium, titanium, chromium, molybdenum, tantalum, tungsten, nickel, cobalt; Or their a kind of alloy.Much less, second electrode can comprise dystectic these metals that have that occur in any combination.Belong to a kind of metal of platinum family such as platinum, rhodium, palladium, or comprise a kind of alloy of these metals,, be suitable as the principal ingredient of electrode material as silver-platinum or platinum-palladium.A kind of metal of preferably using anti-oxidant atmosphere at high temperature is as second electrode, because during the thermal treatment of piezoelectric film, second electrode will expose at high temperature sometimes.
The material that is suitable as second electrode can be to comprise metallic ceramics and the pottery with dystectic a kind of metal, as aluminium oxide, zirconia, monox or glass.
The shape of substrate is not done special restriction, but selects according to its purposes.The shape of substrate is preferably flat.Yet it also can be cylindrical or barrel-shaped.
Fig. 4 is the cut-open view that comprises the particle sensor 40 of sensor element 10.Sensor element 10 can be fixed on the wall (not shown) by thread part 41, thereby the end 10a that is arranged on the detecting unit 20 is outstanding from wall, and contacts with the fluid that will detect.
The protected lid 44 of the end 10a of sensor element 10 covers.Over cap 44 has a plurality of through holes, so fluid can flow into over cap 44.
Because the other end 10b of sensor element 10 links to each other with lead 46, so the electric signal that is present on dististyle 32 and 34 can be transferred on the lead-in wire 47 and 48.The end 10b of sensor element 10 and lead 46 insert shell 45.One end of shell 45 seals with end piece 49.Lead-in wire 47 and 48 passes end piece 49.
The method of manufacturing sensor element 10 of the present invention is described below.
The moulding layer of undressed sheet material or band stacks by hot pressing, obtains holistic substrate through sintering then.For example, in the substrate 12 of Fig. 1, three layers of undressed sheet material or band are stacked.The preformed second layer has the through hole of reservation shape, so that form closed resonator 18.Can pass through method cambium layer such as pressing mold, stream casting, injection molding.Can form resonator cavity by machining, for example cutting, grinding, Laser Processing, die-cut etc. by pressure processing.Do not need to make layer all to have identical thickness.Yet, preferably because sintering all has identical shrinkage factor for every layer.
When resonator cavity is (i.e. the depression) of opening, can molded undressed sheet material or band, so that have before the sintering shape corresponding to recess.In addition, also can form resonator cavity by the machining behind the sintering.
Be described in the method that forms detecting unit 20 on the ceramic oscillating component 14 now.Form piezoelectrics by the compression moulding that utilizes mould, the band forming process of utilizing slurry etc.Before sintering, piezoelectrics are stacked on the oscillating component of substrate by hot pressing.Then, this lamination forms substrate and the piezoelectrics that connect together through oversintering.This method need form electrode 26 earlier by a kind of method of following formation film on substrate.
Though the sintering temperature of piezoelectric film is suitably to determine according to the material that constitutes film, generally is 800 ℃-1400 ℃, preferably 1000 ℃ to 1400 ℃.Preferably piezoelectric film is with the evaporation source sintering of the piezoelectric film material of existence, so that the component of control piezoelectric film.
On the other hand, in the method that forms film, second electrode 26, piezoelectric film 22 and first electrode 24 are stacked on the oscillating component 14 by this order, form detecting unit 20.Can adopt a kind of method of the formation film in the routine techniques, for example form a kind of method such as the silk screen print method of thick film, a kind of application process such as infusion method, film forming a kind of method such as ion beam method, sputter, vacuum deposition method, ion plating, chemical vapor deposition (CVD) method, or electrochemical plating.From making the viewpoint of film reliably, most preferred method is a silk screen print method in these methods.Yet the method that forms film is not limited to these methods.By silk screen print method second electrode 26, lead-in wire 28, lead-in wire 30, dististyle 32 and dististyle 34 are added on the substrate simultaneously.Preferably form piezoelectric film 22 by methods such as serigraphy, immersion, plated films.These methods employings comprise cream or the slurry as a kind of ceramic powders of principal ingredient of piezoelectric film material, therefore form piezoelectric film 22 on the substrate that has detecting unit 20, and it is specific that it has extraordinary piezoelectricity.Form piezoelectric film without any need for bonding agent by a kind of method in these methods that form film, and detecting unit and oscillating component can be connected together integrally.Therefore, it seems preferred especially this method from outstanding reliability, outstanding reproducibility and the viewpoint that is easy to integration.The shape of this film can be suitable pattern.Can form pattern by a kind of method, for example serigraphy or photoetching, or remove unwanted part formation pattern by the machining as Laser Processing, section or ultrasound wave.
The shape of piezoelectric film, first electrode and second electrode is unrestricted fully, can adopt Any shape according to its purposes.For example, they can be polygons, as triangle and rectangle, and shaped form such as circle, ellipse and annular, pectination shape, grid, or these combination of shapes get up are formed a special shape.Detecting unit 20 does not need to be plated in the whole surface of oscillating component 14.Detecting unit 20 preferably is plated on the part of oscillating component 14, and oscillating component 14 is because vibration has big displacement.
Each tunic in the film 22,24,26 that forms like this with a kind of shape of substrate all will be respectively through bakingout process when forming, so this tunic and substrate become integral body.In addition, can heat-treat all films simultaneously, connect film and substrate so that integral body connects all.When forming first electrode or second electrode, always need not heat-treat in order to make these electrodes become integral body by film forming a kind of method.
In sensor element of the present invention, only need a detecting unit.Yet more than one detecting unit can be positioned on the oscillating component.In this case, preferably provide more than one oscillating component, so that cause vibration independently with respect to each detecting unit.When sensor element had more than one same detection unit, for a stress of giving sizing of oscillating component, output signal can improve.In other words, when detecting unit has different structures, detect the various values of mechanical impedance, therefore can judge and detect size, quality and the quantity of particle.
In Fig. 5, sensor element 50 comprises substrate 52 and lays respectively at two detecting unit 60a and 60b on two oscillating component 54a and the 54b.In substrate 52, oscillating component 54a, 54b and fixed part 56 become integral body.Oscillating component 54a, 54b and fixed part 56 form the part of substrate 52.Detecting unit 60a and 60b lay respectively on oscillating component 54a and the 54b.Sunk part 58a and 58b be respectively formed at oscillating component 54a and 54b below, as resonator cavity.Substrate 52 is formed with sunk part 58a and 58b, and towards oscillating component 54, so among oscillating component 54a and the 54b each is all very thin from the surperficial 52t of substrate 52.To fixed part 56 location, so that surround oscillating component 54a and 54b.
Detecting unit 60a and 60b have piezoelectric film 62a and 626 respectively, cover the first electrode 64a and the 64b of at least a portion of the outside surface 62s of piezoelectric film 62a and 626, and the second electrode 66a and the 66b of at least a portion that covers the inside surface 62t of piezoelectric film 62a and 62b.The second electrode 66a and 66b cover the surperficial 54s of oscillating component 54a and 54b respectively at least.
Might detect particle with detecting unit 60a, and compensate the particle that detects by unit 60a with unit 60b.Be covered with filtrator 59 in the sunk part 58b.Because filtrator 59 is formed with the thin through hole with preliminary dimension, so only can flow into sunk part 58b less than the particle of clear size of opening.When the particle among the sunk part 58b contacts or particularly collides with oscillating component 54b, detecting unit 60b and oscillating component 54b vibration, and the piezoelectric film 62b of detecting unit 60b is transformed into electric signal with vibration.Therefore, from the output of detecting unit 60b with have certain size or relevant less than the particle of certain size.Output from detecting unit 60b also can be represented basic variation, as the variation in hydrodynamic pressure, fluid velocity and the fluid temperature (F.T.).
On the other hand, because sunk part 58a without any filtrator, can enter sunk part 58a so have the particle of various sizes.When particle contacted with oscillating component 54a, detecting unit 60a exported electric signal.Therefore, the output of detecting unit 60a is relevant with the particle of various sizes.
Therefore the output of detecting unit 60a and the output of detecting unit 60b can be compared, so that the precision of the particle in the compensation test fluid.In addition, the output of detecting unit 60a can be deducted, so that error is compensated from the output of detecting unit 60b.
In Fig. 6 (a) and Fig. 6 (b), sensor element 70 comprises substrate 72 and is positioned at three detecting units 80 on three oscillating components 74 of substrate 72.Oscillating component has the semi-girder shape, and substrate 72 has resonator cavity 78.
Oscillating component 74 is outstanding from fixed part 76, and fixed part 76 is parts of substrate 72.Oscillating component is flexible.The edge of each oscillating component has the otch that links to each other with resonator cavity 74.It should be noted that though that three oscillating components 74 shown in Fig. 6 (a) are parallel to each other is outstanding, oscillating component does not need to be parallel to each other.
Detecting unit 80 lays respectively on the oscillating component 74.Second electrode 86 covers the surface of oscillating component 74.The part of each oscillating component 74 is not covered by second electrode, leaves a frame.Piezoelectric film 82 covers second electrode 86, and is stacked in above it.Do not covered by piezoelectric film 82 by the frame of the oscillating component 74 of second electrode, 86 coverings.First electrode 34 covers the surface of piezoelectric film 32.A part of surface of every lamination electrolemma 84 is not covered by first electrode 84.
The method that adopts sensor element of the present invention is described below.
When alternating voltage when pair of electrodes is applied on the piezoelectric film, by inverse piezoelectric effect, detecting unit and vibration unit vibration.By to electrode application voltage, available this effect detects particle or viscosity.In addition, can be by not detecting particle to electrode application voltage yet.
For the particle in the test fluid when not applying voltage, fluid must flow.Preferably flow velocity is relatively stable.For example, when the lubricant in the internal combustion engine is fluid, preferably can keep fluid in certain flow velocity current downflow when oil pump or similar device work.Even oil pump or similar device are not worked, lubricant also can vibrate by the mechanical vibration that caused by internal combustion engine operation.In addition, sensor element is rotated or translation motion in detected fluid, so particle in the fluid and sensor element collision.
On the other hand, for detecting particle by applying voltage to electrode pair, the electric signal that frequency transfers to proximity transducer parts resonance frequency is applied on the electrode, so that make detecting unit vibration, the viscosity of particle in the test fluid and/or test fluid thus.In this case, fluid can or flow or keep static.
No matter whether applied voltage to electrode, the signal owing to there is particle from detecting unit output all is very little usually, so this output signal is preferably amplified by an amplifying circuit.Output signal is relevant with the quantity of particle size and particle, and the circuit that comprises amplifying circuit is transformed into the classification of particle size with output signal, so that the scope of particle size in the test fluid.It should be noted, when output signal is enough big, can not need amplifying circuit.
In sensor element of the present invention, do not need bonding agent that detecting unit is linked on the oscillating component, because detecting unit is located immediately on the oscillating component.Therefore detecting unit can work at high temperature.Sensor element has very long serviceable life, because there is not bonding agent can be subjected to the erosion of lubricant etc.In addition because material that sensor element does not impact with any absorption such as bonding agent and since piezoelectric film and oscillating component approach, so sensor element has very high detection sensitivity.Moreover the particle that sensor element can detect even very little, and magnetic, nonmagnetic or diamagnetic particle.
Though the present invention has been made specific descriptions according to some embodiment, the invention is not restricted to the foregoing description.Knowledge should be understood, under the prerequisite that does not break away from the principle of the invention, various changes, modification and improvement etc. can be made according to one of ordinary skill in the art.
Claims (10)
1. the sensor element of a detection irrelevant solid particle in fluid comprises:
Oscillating component with enough quality is used for the collision with solid particle is responded; And
Be used for the vibration of described oscillating component is transformed into the equipment of electric signal, so that detect this vibration.
2. a kind of sensor element of claim 1, wherein said equipment comprise that at least one is transformed into the device of electric signal with vibration, and this device is to choose from comprise the group with lower device:
Piezo-electric device;
Electromagnetic induction device;
The electric capacity modifier;
Light is transmitted into described oscillating component, and detect receives the device that the light of the part of light changes;
The change of the resistance that will cause owing to the stress in the conductor is transformed into the device of electric signal; And
The change of the resistance that will cause owing to the stress in the semiconductor is transformed into the device of electric signal.
3. the sensor element of detection solid particle in fluid comprises:
Detecting unit comprises the piezoelectric film that substantially is made of first stupalith, is coated in first electrode at least a portion of outside surface of described piezoelectric film and is coated in second electrode at least a portion of inside surface of described piezoelectric film;
The basic oscillating component that constitutes by second stupalith, described detecting unit is positioned on the described oscillating component, and therefore described second electrode is coated at least a portion of described oscillating component; And
The fixed part that is used for fixing described oscillating component, therefore described oscillating component can vibrate;
Wherein when described detecting unit and/or described oscillating component when solid particle in the fluid contacts, described piezoelectric film is transformed into electric signal with vibration.
4. a kind of sensor element of claim 3, wherein said oscillating component and described fixed part are the ceramic substrate parts with single chip architecture, and described ceramic substrate is formed with resonator cavity, therefore described oscillating component has the very little sheet shape of thickness.
5. a kind of sensor element of claim 3, wherein said first stupalith comprises a kind of material of selecting at least from following group, this group comprises: lead zirconates, lead magnesium niobate, lead niobate nickel, lead niobate zinc, lead niobate manganese, lead stannate antimony, lead titanates, lead tungstate magnesium, lead niobate cobalt and barium titanate.
6. claim 1 or a kind of sensor element of 3, wherein fluid comprises lubricant.
7. a kind of sensor element of claim 3, the thickness range of wherein said piezoelectric film is from 1 to 100 micron, the thickness range of described oscillating component is from 1 to 100 micron.
8. claim 1 or a kind of sensor element of 3, wherein said oscillating component comprises stable zirconia.
9. a sensor comprises
A sensor element comprises
Detecting unit comprises the piezoelectric film that substantially is made of first stupalith, is coated in first electrode at least a portion of outside surface of described piezoelectric film and is coated in second electrode at least a portion of inside surface of described piezoelectric film;
The basic oscillating component that constitutes by second stupalith, described detecting unit is positioned on the described oscillating component, and therefore described second electrode is coated at least a portion of described oscillating component;
The fixed part that is used for fixing described oscillating component, therefore described oscillating component can vibrate;
Wherein when described detecting unit and/or described oscillating component when solid particle in the fluid contacts, described piezoelectric film is transformed into electric signal with vibration; And
Cover the over cap of described detecting unit.
10. the method for the solid particle in the test fluid, wherein claim 1 or 3 sensor element be with respect to the fluid motion that is verified, and makes that therefore irrelevant solid particle collides with described oscillating component in the fluid that is verified.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN 95115106 CN1143184A (en) | 1995-08-14 | 1995-08-14 | Sensor element and particle sensor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95115106 CN1143184A (en) | 1995-08-14 | 1995-08-14 | Sensor element and particle sensor |
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| CN1143184A true CN1143184A (en) | 1997-02-19 |
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103411858A (en) * | 2013-07-24 | 2013-11-27 | 华北电力大学 | On-line particle size distribution measuring device and method based on array sonic transducer |
| WO2015169217A1 (en) * | 2014-05-06 | 2015-11-12 | 无锡华润上华半导体有限公司 | Pressure sensor and manufacturing method therefor |
| CN105241795A (en) * | 2015-09-30 | 2016-01-13 | 江苏苏净集团有限公司 | Atmospheric particle concentration detection device and detection method |
| CN105699265A (en) * | 2016-03-29 | 2016-06-22 | 北京至感传感器技术研究院有限公司 | Method and device for detecting ferromagnetic grains in liquid oil |
| CN105806760A (en) * | 2016-05-19 | 2016-07-27 | 北京至感传感器技术研究院有限公司 | Online oil liquid quality sensor |
| CN105987776A (en) * | 2014-08-22 | 2016-10-05 | 利永环球科技股份有限公司 | Instant response pressure sensor |
| CN107078205A (en) * | 2014-08-04 | 2017-08-18 | 陶瓷技术有限责任公司 | Guard electrode for piezoceramic transducer |
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| CN103411858B (en) * | 2013-07-24 | 2015-10-21 | 华北电力大学 | Based on the particle size distribution on-line measurement device and method of array sonic transducer |
| CN103411858A (en) * | 2013-07-24 | 2013-11-27 | 华北电力大学 | On-line particle size distribution measuring device and method based on array sonic transducer |
| US10101225B2 (en) | 2014-05-06 | 2018-10-16 | Csmc Technologies Fab1 Co., Ltd. | Pressure sensor with light detection of diaphragm protrusion |
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| CN105092110A (en) * | 2014-05-06 | 2015-11-25 | 无锡华润上华半导体有限公司 | Pressure sensor and manufacturing method thereof |
| CN107078205A (en) * | 2014-08-04 | 2017-08-18 | 陶瓷技术有限责任公司 | Guard electrode for piezoceramic transducer |
| CN105987776A (en) * | 2014-08-22 | 2016-10-05 | 利永环球科技股份有限公司 | Instant response pressure sensor |
| CN105241795A (en) * | 2015-09-30 | 2016-01-13 | 江苏苏净集团有限公司 | Atmospheric particle concentration detection device and detection method |
| CN105241795B (en) * | 2015-09-30 | 2018-12-07 | 江苏苏净集团有限公司 | A kind of detection device and detection method of airborne particulate concentration |
| CN105699265A (en) * | 2016-03-29 | 2016-06-22 | 北京至感传感器技术研究院有限公司 | Method and device for detecting ferromagnetic grains in liquid oil |
| CN105806760A (en) * | 2016-05-19 | 2016-07-27 | 北京至感传感器技术研究院有限公司 | Online oil liquid quality sensor |
| CN111801483A (en) * | 2017-12-15 | 2020-10-20 | 贝克休斯控股有限责任公司 | Downhole component accumulation damage sensor |
| CN112974201A (en) * | 2019-12-13 | 2021-06-18 | 意法半导体股份有限公司 | Micromachined ultrasonic transducer including tunable Helmholtz resonator |
| US11872591B2 (en) | 2019-12-13 | 2024-01-16 | Stmicroelectronics S.R.L. | Micro-machined ultrasonic transducer including a tunable helmoltz resonator |
| CN111001553A (en) * | 2019-12-18 | 2020-04-14 | 武汉大学 | Tunable ultrasonic sensor array |
| CN111001553B (en) * | 2019-12-18 | 2021-01-26 | 武汉大学 | Tunable ultrasonic sensor array |
| CN114152646A (en) * | 2021-10-29 | 2022-03-08 | 电子科技大学中山学院 | Molybdate volatile organic compound detection device |
| CN114152646B (en) * | 2021-10-29 | 2023-06-30 | 电子科技大学中山学院 | Molybdate volatile organic compound detection device |
| CN116222713A (en) * | 2023-03-21 | 2023-06-06 | 深圳艾依灵科技有限公司 | Sanitation truck weighing sensor and control method thereof |
| CN116222713B (en) * | 2023-03-21 | 2023-09-01 | 深圳艾依灵科技有限公司 | Sanitation truck weighing sensor and control method thereof |
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