METHOD FOR MANUFACTURING A BEND TRANSDUCER, A MICROPUMP AND A MICROVALVE, MICROPUMP AND MICROVALVE

专利摘要:
method for manufacturing a bending transducer, a micropump and a microvalve, micropump and microvalve. there is provided a method of manufacturing a bend transducer comprising a driving means and a membrane, the method comprising: providing (1010) the membrane (110) and the driving means (210); and applying (1020) a production (uproduction) signal to the driving means (210) during a connection of the driving means to the membrane (110) such that the driving means is pre-strained after the connection, wherein the output signal is of the same type as an operate signal to operate the warp transducer.
公开号:BR112012022433B1
申请号:R112012022433-6
申请日:2010-03-05
公开日:2021-06-29
发明作者:Martin Richter；Martin Wackerle；Markus Herz
申请人:Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.；
IPC主号:

专利说明:

DESCRIPTION HISTORY OF THE INVENTION
The present invention relates to a method for making a bend transducer, a micropump and a microvalve, and a micropump and a microvalve comprising the bend transducer manufactured in accordance with the method. DESCRIPTION OF THE PRIOR TECHNIQUE
According to the prior art there are a large number of different membrane micropumps, the conduction concepts used being electromagnetic, thermal and piezoelectric conduction principles. However, almost all membrane micropumps available on the market are driven by the 15 principles of piezoelectric conduction.
The compression ratio of micropumps is an important parameter that defines the bubble tolerance and back pressure capability of micropumps when gases are the medium to be pumped. As for fluid pumps, the 20 gas pumps can at any time enter the pump chamber, the back pressure capacity for liquid pumps is also defined - in practice - by the compression ratio (in addition to the large force actuation diaphragm and low valve leakage). The compression ratio is defined as the ratio between the volume displaced by the pump membrane in one breath or cycle, the so-called systolic volume, and the dead volume, that is, the minimum volume remaining when the pump membrane was moved to pump the medium contained in the pump chamber out of the pump chamber. Dead volume can also be referred to as the difference in volume between the maximum pump chamber volume and the stroke volume. The compression ratio of known micropumps is relatively small and within the range of 0.1 to 1.
Patent application publication EP 0 424 087 A1 describes, for example, a micropump with a piezoelectric means being deformable through voltage signals in the first and second directions, i.e. upwards and downwards, in order to respectively drain the liquid and expel the liquid from the liquid reservoir of the micropump. The micropumps described in EP 0 424 087 A1, however, are disadvantageous in that they comprise relatively large dead volumes or only allow small taps in the upward direction and thus only small systolic volumes.
Furthermore, the compression ratio of piezoelectrically driven membrane micropumps is typically defined by the following boundary conditions. When applying a positive voltage to a piezo-membrane transducer, the membrane transducer can only be deflected in the downward direction. Upward deflection is only possible by applying a negative voltage, where only 20% of the descending systole is achievable, otherwise the piezoelectric ceramic would be depolarized. By restricting membrane movement to downward movement it is difficult to reduce dead volume and increase the compression ratio. Therefore, for conventional micropumps, see, for example, the membrane micropump of US 2005/0123420 A1 and the peristaltic micropump of US 6,261,066 Bl, the piezoelectric medium is only moved in one direction and/or the pump chamber is formed so that its contour is matched to the membrane's fold line to reduce dead volume and thus maximize the compression ratio. This adaptation to the bending line of the pumping membrane is complex and costly in relation to production engineering, and furthermore a complete adaptation to the bending line is typically not possible due to the pumping membrane not completely deflecting symmetrically, by example, due to distortions of the pumping membrane due to the gluing process, so that spaces remain within the pump chamber which reduce the compression ratio. In addition, the stroke volume of a standard trigger is limited through boundary conditions if the diaphragm edges are stapled. Finally, with silicon this alignment can only be partially achieved by engraving several steps on the insert, which takes a great deal of effort.
US 5,759,014 describes a micropump with a silicon pumping membrane arranged in a glass base plate and an inlet valve and an outlet valve 20 arranged opposite each other on opposite sides of the pumping membrane. The pumping membrane has an outwardly curved shape in the rest position. A piezoelectric element is attached to the top of the membrane. In case the piezoelectric element is activated, the membrane moves downwards. The outwardly curved shape of the membrane can be obtained by vacuuming the chamber located above the hermetically sealed membrane or applying to its upper surface an oxide layer including a suitable pre-strain deformation. Micropumps according to US 5,759,014 are disadvantageous in that the dead volume caused by the connection spaces between the pumping chamber and the inlet and outlet valve is still considerably high, the achievable bulging heights of the membrane are limited (thus, only facilitating limited compression ratios), and require a considerable amount of circular regions of silicon oxide on the lower surface of the membrane to prevent adhesion or suction of the membrane. Additionally, the lateral arrangement of the valves significantly increases the resistance to flow in the pump chamber, whereby the stroke volume can only carry at very low pump frequencies, limiting the maximum pump frequency. Another disadvantage of bulging through the oxide or vacuum layer is the fact that if a piezoelectric is actuated by a positive voltage, the diaphragm cannot be moved to a completely empty position. Thus, a dead volume at the edge of the diaphragm remains.
Document US2009/0158923 A1 describes a pre-stressing of the pump diaphragm performed by laser welding of two layers of metal. This order states that (obviously due to the thermal impact of the welding process) a pre-stressing of the diaphragm and the pump chamber can be carried out. However, again, a large dead volume (which is even greater than the dead volume due to the oxide layer in US 5,759,014) remains at the edge of the diaphragm after the piezoelectric is actuated.
In fact, the joining of the drive membrane with the pump chamber via laser welding as shown in Fig. 8 causes an inevitable bulging of the membrane, which is not optimized in relation to a minimized dead volume. Fig. 8 shows two schematic drawings of a micropump with a pump body 810 and a membrane 820 secured to the pump body by laser welding on the membrane edge of the pump. The upper part of Fig. 8 shows the membrane of the pump 820 in a pre-tensioned, non-actuated state, and the lower part of Fig. 8 shows the same membrane 820 bent down through a piezoelectric element 830 arranged in the upper part of the pump membrane. As can be seen from the bottom of Fig. 8, the membrane 820 is not completely flat, but shows bulges or deflections 840 on the edge of the pump membrane which causes an increased dead volume due to the volumes defined across these 840 protrusions on the edge. of the membrane.
Documents US 2004/0036047 A1 and US 2006/0027772 A1 describe normally closed valves. Formed from a stack of two silicon chips, the bottom silicon chip comprising the valve inlet and outlet, and the top chip mounted on the bottom chip comprising a valve chamber recess, a valve cap. and a boss on one side facing the bottom chip, and a recess on the opposite side of the top chip facing away from the bottom chip to define a membrane, wherein on the membrane above the boss a piezoelectric unit is arranged to move a valve plug. formed on the bottom chip down to open the valve.
In a closed state, ie when the piezo ceramic is not actuated, the valve cover fluidly disengages the valve inlet from the valve chamber. In case the piezoelectric ceramic is actuated, the piezoelectric ceramic moves under the valve plug that is connected to the membrane through the shoulder. In this case, the valve cover no longer rests on the shoulder and the valve is opened. It has been recognized that a membrane sometimes tends to be deflected in the downward 5 direction after valve production. In case these deflections in a downward direction are too large, the valve may not meet the density requirements for normally closed valves or may open at slight pressures in the reverse direction of the membrane. Such unwanted flows in the non-actuated state of the need for the valve are disadvantageous and can even be critical in the fields of medical technology or fuel cells.
It is the aim of the present invention to provide a method of manufacturing a bending transducer allowing to eliminate one or all of the above mentioned disadvantages of the prior art. It is another objective of the present invention to provide a micropump that is capable of providing high compression ratios and that can be easily engineered into production. Yet another object of the present invention is to provide a microvalve with reliable density characteristics. SUMMARY OF THE INVENTION
The object of the present invention is achieved through a method of manufacturing a bending transducer according to claim 1, a method of manufacturing a micropump according to claim 13, a method of manufacturing a microvalve according to claim 14, a micropump according to claim 17 and a microvalve according to claim 20.
Embodiments of the present invention provide a method of manufacturing a bending transducer comprising a driving means and a membrane, the method comprising: providing the membrane and the driving means; and applying a production signal to the conduction means during a connection of the conduction means to the membrane such that the conduction means is pre-strained after connection, wherein the production signal is of the same type as a signal. operating time to operate the bend transducer.
The bend transducer embodiments comprise a membrane and membrane-attached driving means, wherein the driving means is attached to a main surface of the driving means to the bendable or deflectable membrane in order to convert an operating or drive signal. applied to the drive means in a movement of the bending transducer vertically to the main surface through which the driving means is bent to the membrane. In other words, the operating signal effects a change in dimension (contraction or extraction) of the conduction means parallel to the main surface through which the conduction means is attached to the membrane (also referred to as dimension or lateral direction) which is converted to a vertical movement relative to the main surface through which the driving means is attached to the membrane (also referred to as vertical dimension or direction). The degree of conversion is defined by the coefficient d31 of the conduction medium. Due to the manufacturing method of these bending transducers being pre-tensioned or pre-bent. Such pre-strained bending transducers can be used in micropumps and microvalves to overcome the aforementioned problems.
The driving means can be, for example, piezoelectric driving means or any other driving means which is adapted to change its volume or at least one dimension when a certain type of triggering or input signal is applied to the driving means. In the case of the piezoelectric conduction means, the production signal and the application signal are voltages applied to the piezoelectric conduction means. In case positive voltages are applied, the piezoelectric conduction means contracts, and thus, moves the membrane towards the membrane relative to a connecting surface between the conduction means and the membrane.
Alternative embodiments of the conduction means are, for example, magneto-restrictive conduction means or conduction means comprising magneto-restrictive materials which change their volume in case a magnetic field is applied to the magneto-restrictive conduction means. In this case the production signal and the operating signal (the signal applied to the conduction medium during subsequent normal operation) are electromagnetic fields.
As becomes apparent from the above-mentioned examples, the production signal and the operating signal are of the same type as a signal (voltages for piezoelectric conduction means, magnetic fields for magneto-restrictive conduction means).
The magnitude of the production signal (voltage level of the production signal and the operating signal for piezoelectric conduction medium, magnetic field strength for the magneto-restrictive conduction medium) may be the same or it may be different for the production signal and the operating sign.
The polarity or direction of the production signal (voltage polarity for piezoelectric conduction means, magnetic field direction for magneto-restrictive conduction means) may be the same or it may be different, eg inverse, for the production signal and the operating sign.
In case the polarity or direction of the production signal and the operating signal is the same, the type of pre-bulge of the bending transducer (of the membrane and/or of the conduction medium) achieved through the inventive method is exactly the same than the corresponding systole of the membrane or bend transducer when the driving medium is actuated.
In certain embodiments the production signal has the same polarity as the production signal and the magnitude of the production signal the same magnitude as the production signal or a smaller magnitude or a higher magnitude, depending on the application.
Other embodiments of the invention provide a method for producing a micropump, the micropump comprising a bending transducer with a membrane and a driving means, wherein the membrane forms a membrane of the pump and is adapted to be moved between a first curved position and a second less curved position through a driving means; and a pump body connected to the pump membrane so as to define the pump chamber between the pump body and the pump membrane; the method comprising manufacturing the bending transducer by the inventive method so that the pump membrane assumes a pre-curved shape in the first curved position when the driving means is not actuated.
Still other embodiments of the invention provide a method for producing a microvalve, the microvalve comprising a bending transducer with a membrane and a driving means, wherein the membrane forms a valve membrane and is adapted to be moved between a first position and a second position through the driving means to open or close the microvalve; the method comprising: fabrication of the bending transducer by the inventive method.
The embodiments also provide a micropump, the micropump comprising: a bending transducer comprising a membrane and a driving means, wherein the membrane forms a membrane of the micropump pump and is adapted to be moved between a curved first position and a second position less curved through the driving medium; and a pump body connected to the pump membrane so as to define the pump chamber between the pump body and the pump membrane; wherein the pump membrane assumes a pre-curved shape in the first curved position when the driving means is not actuated, and wherein the bending transducer has been manufactured by the inventive method.
The embodiments further provide a microvalve comprising: a bending transducer comprising a membrane and a driving means, wherein the membrane forms a valve membrane and is adapted to be moved between a first position and a second position through the driving means to open or close the microvalve; wherein the bend transducer has been manufactured by the inventive method.
The realizations of the present invention are based on the discovery that the micropump bulges 840 in Fig. 8 and the corresponding dead volumes are caused by the fact that the fold shape of the pre-stressed diaphragm or membrane is not exactly the same as the systole corresponding to the piezoelectric actuator. In other words, the deflection of the pre-stressed membrane caused by pre-stressing during production (eg oxide layer or laser welding) is different from the deflection of the membrane caused by the piezoelectric driver during micropump operation.
Embodiments of the present invention allow to maximize the compression ratio by providing a pre-bulging method for the pump membrane, which is adapted to the movement of the piezoelectric membrane or, in general, to the actuating movement of the membrane. Thus, bulges 840 and corresponding dead volumes can be avoided or at least reduced. In order to achieve a pre-bulge of the pump membrane which is adapted to the movement of the pump membrane caused by the driving means attached to the pump membrane, the method embodiments comprise the step of connecting the driving means to the pump membrane in such a way that the pump membrane assumes a pre-curved shape when the driving means is not engaged. Thus, when the conduction means is actuated, and correspondingly the membrane assumes the second less curved position, the voltage or stress of the pump membrane caused by the conduction medium in the non-actuated state is reduced. In embodiments of the method for producing the pre-curved pump membrane, the driving means can, for example, be connected to the pump membrane when both have a flat shape. Due to different temperature coefficients and/or the application of a production signal to contract the conduction means laterally when connecting the conduction means to the pump diaphragm, the pump diaphragm with the conduction means assumes a pre-curved upward shape in the - • first bent position when the driving means is not activated. The actuation of the driving means causes the driving means to contract again (at the same time reducing the voltage of the pump membrane), the downward deflection of the membrane representing the reverse deflection for the pre-bulge, and in the case of the signal of driving means for driving or driving the driving means is strong enough to cause the driving means to again assume the flat shape or at least an essentially flat shape without or at least negligible protrusions on the edge.
In other words, the deformation of the membrane caused by the actuation of the conduction means represents the reverse effect and deformation caused by the pre-bulging and thus at least reduces the bulges or deflections 840 at the edges of the membrane of the pump.
In still other words, the embodiments of the present invention provide micropumps, in which the shape of the fold of the pre-curved pump membrane is adapted to the deformation caused by actuation of the driving means, so that the pump membrane faces the Pump body has a flat base shape when the pump membrane is in the second least curved or flat position and no back pressure is applied. The term "flat base shape" indicates that in case the pump chamber base is flat or flat with cavities, the pump membrane has a flat shape, and in case the pump chamber base or pump membrane comprises protrusions and non-stick means distributed along the base of the pump chamber, the pump membrane can be slightly curved outwards at the edge of the base of the pump chamber, where most of the non-stick means are ■ - arranged and assume, from this, towards the central part of the pump chamber a flat shape carried through the non-stick protrusions due to its rigidity.
According to one embodiment of a method of producing the micropump, the driving means, e.g. piezoelectric driving means, is connected to the membrane of the pump in a contracted state, i.e., a predetermined production signal or voltage is applied to the medium. of conduction to cause contraction of the conduction medium, and the signal voltage is released thereafter. Due to the release of the signal or voltage, the driving medium extracts and thus bends the membrane with “the driving medium up and away from the pump chamber.
According to another embodiment of a micropump production method, the pump membrane and the driving means, for example a piezoelectric driving means, are further heated to a predetermined production temperature, they are connected together at this production temperature , and are cooled, for example, to a normal room temperature thereafter. Due to the thermal expansion coefficients of the conduction medium and the pump diaphragm, the bending transducer is additionally pre-stressed.
On the one hand, this effect can be used to produce bending transducers with increased pre-tension characteristics which can, for example, be used to provide valve or pump membranes with yet other increased pre-bulge heights. in the case of different temperature expansion coefficients of the conduction medium and the pump diaphragm would normally lead to a pre-bulging in the downward direction (from the conduction medium towards the pump diaphragm) a production signal can be applied from so that a pre-bulging of the pump membrane in a first direction effected by releasing the production signal more than compensates a pre-bulging of the pump membrane in a second direction opposite to the first direction effected by cooling after the conduction medium and the pump membrane, for example, for normal or ambient temperature.
This second aspect is in particular advantageous for semiconductor membranes which have thermal expansion coefficients typically lower than piezoelectric ceramics or other piezoelectric conduction means, thus leading to unwanted pre-bulging in a downward direction. By applying a production signal to the piezoelectric conduction means which causes the piezoelectric conduction means to contract, a downward pre-bulging can be further compensated for and thus a pre-bulging in an upward direction (from the membrane of the pump towards the piezoelectric conduction medium) can be reached.
Thus, normally closed valves as described in US 2004/0036047 A1 and US 2006/0027772 A1 can be more reliably closed or sealed in the non-actuated state by pre-tensioning the bending transducer formed by the piezoelectric driving means and the membrane of silicon.
Regarding micropumps, the compression ratio c of micropumps is defined by the ratio of stroke volume ΔV and dead volume Vo, that is, c = ΔV/V0. Therefore, two measures can primarily be taken into account to increase the compression ratio. First, to increase stroke volume ΔV, and second, to reduce dead volume Vo. The embodiments of the invention make it possible to solve both measures and thus to increase the compression ratio.
The arrangement of the inlet and outlet check valve opposite and below the membrane and inside the pump body allows to achieve high stroke volumes while reducing dead volumes. The pre-bulging of the pump membrane, moreover, only needs to use or drive the conduction means, and in particular the piezoelectric conduction means, in one direction (i.e., in the downward direction only), and thus reduce the complexity of the steering means and in case of piezoelectric conduction means reduce the risk of depolarization.
Depending on the shape of the upper surface of the pump body forming the base of the pump chamber, and the shape of the pumping membrane in the less curved second position, the dead volume of the micropump can be reduced. Therefore, the micropump embodiments comprise, for example, no spacing means or spacing structures arranged between the pump membrane and the pump chamber base, and further comprises an at least essentially flat pump chamber base, wherein the shape of the pump membrane and the shape of the base of the pump chamber coincide when the pump membrane is in the second, i.e., essentially flat position, and thus provide a microvalve whose dead volume of the pump chamber is essentially only defined through the volumes dead from the valve wells.
Micropump embodiments may comprise completely flat pump bodies, where the entire pump body (not just the part of the pump body defining the pump chamber base) is essentially flat (eg flat except for the valve wells) . Such completely flat surfaces or pump bodies are easy to produce, regardless of whether silicon or other semiconductor materials, metal materials or polymers are used to produce the pump body, and/or regardless of how the inlet and outlet check valves are produced or integrated. Thus, such achievements also make it possible to reduce the complexity of production engineering.
The dead volumes of the inlet or outlet check valves and/or the valve wells of the inlet and outlet check valves reduce - due to the arrangement of the inlet and outlet check valve opposite the pumping membrane - the effect of sticking and allow easier removal of the pump diaphragm from the pump chamber base and corresponding upward movement of the pump diaphragm. Other embodiments of the micropump comprise inlet and/or outlet check valves which are arranged opposite a central area of the pumping membrane to further lessen the sticking effect and/or lessen the flow resistance.
In other embodiments, the pumping membrane is directly attached to the upper surface of the pumping membrane so that when the pump membrane is moved to the second position and assumes a flat shape, the pump membrane rests on the upper surface also forming the base of the pump chamber, except, for example, the valve wells and/or recesses in the valve frames on the sides of the valves facing the pump chamber. "Directly attached" in this context is to be understood that the pump membrane can be connected to the pump body with bonding material such as glue, or without bonding material (i.e. without bonding material), by example using ultrasonic bonding, laser bonding etc., however, no layers or spacing elements between the pump membrane and the pump body which could cause a gap between the pump membrane and the base of the pump chamber when the pump membrane is in the second flat position...
Therefore, embodiments of the present invention provide micropumps with a self-protective behavior, and are suitable for transporting compressible media such as gases and are, in addition, bubble-tolerant and bubble-independent.
Micropumps are considered bubble tolerant when they are adapted so that if the bubble is entering the pump chamber the micropump is still running, and the bubble (or a part of the bubble) will be transported through the pump chamber. However, the pump speed can be changed, during the presence of the gas bubble (or parts of it) in the pump chamber.
Micropumps are considered bubble independent when they are adapted so that if the bubble is entering the pump chamber, the micropump is not only still running, but the pump speed is independent of the presence of gas in the pump chamber.
The methods for producing the pre-bulge of the membrane according to the present invention allow to implement particularly high pre-bulge extensions, for example large pre-bulge heights in relation to the lateral extension of the pump chamber, i.e. in relation to to the pump chamber diameter, and thus facilitate not only high pump chamber volumes Vmax, but also, and in particular, high systolic volumes ΔV and finally high compression ratios c.
Additionally, the method embodiments allow to manufacture or produce pre-bent pump membranes or valve membranes - or in general for pre-strain membranes - without requiring additional processing steps, for example, formation of an additional oxide layer. BRIEF DESCRIPTION OF THE DRAWINGS
The embodiments are described below with reference to the attached drawings.
Fig. 1A shows a flowchart of one embodiment of a method for manufacturing a bend transducer.
Fig. 1B shows an embodiment of the micropump, in which the pump membrane itself is in a first position or pre-bent state (in a resting or non-triggered state).
Fig. 1C shows the realization of the micropump according to Fig. 1B in a second position or actuated state, in which the pump membrane assumes a flat shape and rests on the base of the pump chamber.
Fig. 1D shows an intermediate shape of the pump membrane as it moves from the second less curved shape, here flat shape, to the first curved shape.
Fig. 2A shows a cross-section of an embodiment of the micropump with a piezoelectric conduction means mounted on an upper surface of the membrane of the pump (in the first resting or non-actuated state).
Fig. 2B shows a schematic cross section of the micropump according to Fig. 2A in the second actuated state.
Figs. 3A, 3B show schematic cross-sectional views to explain a method of producing a micropump.
Figs. 4A-4F shows schematic sectional views that explain one embodiment of the method for producing a micropump.
Figs. 5A, 5B show schematic sectional views of the micropump produced according to the method described based on Figs. 4A-4F in a triggering and a non-triggering state.
Fig. 6 shows a diagram of normalized fold lines (half-pump membrane) from the center of the pump diaphragm to the edge of the pump diaphragm for different bulging effects or bulging causes.
Fig. 7A shows a diagram of the bend lines of a pump diaphragm from the center of the pump diaphragm to the edge of the pump diaphragm for a piezoelectric connection at 80 °C without applying a production voltage.
Fig. 7B shows a diagram of the fold lines of a pump diaphragm from the center to the edge of the pump diaphragm for a piezoelectric connection at 80 °C and a
Fig. 7C shows a diagram of other pump diaphragm bend lines from the center to the edge of the pump diaphragm for a piezoelectric connection at 80 °C and a production voltage of 73.6 V.
Fig. 7D shows a diagram of different bend lines of a pump diaphragm from the center to the edge of the pump diaphragm for a piezoelectric connection at 80 °C and a production voltage of 178 V.
Figs. 7E, 7F, 7FF, 7G show schematics of a normally closed valve with a pre-tensioned bend transducer.
Fig. 7H shows a first embodiment of a normally open valve with a pre-curved valve membrane.
Fig. 71 shows a schematic of a second embodiment of the microvalve with a pre-bent valve membrane.
Fig. 8 shows a schematic of a micropump with a conventional pre-strained membrane in a driven state and an unpowered state.
Like and/or equivalent elements are denoted in the following description of the figures by means of like or equivalent numerical references. DETAILED DESCRIPTION OF THE INVENTION
Fig. 1A shows a flowchart of an embodiment of a method for manufacturing a bending transducer comprising a driving means and a membrane. In step 1010 the membrane and conduction means are provided. In step 1020 a production signal is applied to the driving means during connection of the driving means to the membrane so that the driving means is pre-stressed after connection, wherein the production signal is of the same type as a signal. operating time to operate the bend transducer. In other words, the production signal is of the same type of signal as the operating signal applied to the driving medium during normal operation of the bending transducer to bend or deflect the bending transducer and membrane.
The production signal is preferably released only after the switch-on has been terminated or is applied during the entire switch-on process.
The link itself can be performed via any link technology. The bonding of the conduction medium to the membrane can be performed without bonding material or using bonding materials, for example, gluing using glue or soldering using liquid solder. Regardless of the specific bonding material, bonding is carried out by means of bonding material arranged between the conduction means and the membrane and the production signal is only released after the bonding material is hardened, preferably completely hardened. In case the production tension is released too soon, for example before the bonding material is completely hardened, the driving means will change its size and thus the extent to which the driving means is pre-stressed after bonding will decrease. .
As described above, application of the production signal leads to a change in the size of the conduction medium, in the case of connecting transducers in a change in dimension parallel to a surface of the conduction medium through which the conduction medium is connected to the membrane. Change can be either a contraction or an extraction. Piezoelectric actuators, for example, contract when a positive voltage is applied and expand to a certain degree if a negative voltage is applied. The embodiments therefore apply a positive producing voltage to the piezoelectric actuator to set the piezoelectric actuator to a contracted state and maintain the piezoelectric actuator in the contracted state until the connection is terminated. After switching on and after releasing the positive production voltage, the piezoelectric actuator tries to extract or expand to its normal size or dimension when not actuated, however, the piezoelectric actuator is clamped over the entire main surface of the membrane trying to maintain its present dimension in the lateral dimension, that is, in the dimension parallel to the contact surface of the piezoelectric conduction medium with the membrane. Thus, the piezoelectric conduction means, the membrane, or in general the bending transducer becomes pre-stressed.
In case the piezoelectric actuator and the membrane are not mechanically connected to any external contour or are only connected at their edges to an external contour, for example, a micropump or microvalve, the release of the production voltage causes the piezoelectric actuator to expand , however, not the normal size would expand in case it is not attached to the membrane. On the other hand, the membrane is also expanded due to the piezoelectric actuator. Thus, the piezoelectric actuator is pre-strained in the sense that the piezoelectric actuator is pre-compressed compared to its normal dimension, wherein the membrane is pre-strained in the sense that it is pre-extended to its normal dimension. At the same time the conduction medium and membrane are pre-bent due to pre-tensioning towards the piezoelectric actuator.
In case the piezoelectric actuator and the membrane are not only fixed at their edges but, for example, also at their centers (see, for example, normally closed valves according to documents US 2004/0036047 Al, US 2006/ 0027772 A1 and Figs. 7E-7G) the membrane and the piezoelectric actuator cannot bend towards the piezoelectric actuator, however they are pre-tensioned and can be considered to be pre-tensioned towards the piezoelectric actuator (pre-tensioned in the sense that the piezoelectric actuator is compressed and prevents, for example, an unwanted pre-bulging in the downward direction due to other production parameters).
The same considerations apply to any other usable driving means for bend transducers.
In the embodiments using glue to bond the conduction medium to the membrane, the glues often require a certain predetermined production temperature higher than the normal room temperature. Thus, different temperature coefficients of the conduction medium and the membrane can cause additional pre-strain that supersedes the pre-stress caused by the production signal. In the case of a pre-stressing of the production signal and the pre-strain caused by the different temperature expansion coefficients are of the same type (for example, both lead to a compression of the conduction medium after switching on or both lead to a pre-extension of the conduction medium after switching on) the sum of the pre-strain, where in the case of the production signal pre-strain and the pre-strain caused by the different temperature expansion coefficients are different, for example, from a reverse or reverse type (eg pre-strain applying a production signal would cause a compression where as a pre-strain caused by different temperature coefficients would cause a pre-strain, or vice versa) the pre-strains they can compensate each other at least partially.
It is another discovery of the present invention that this pre-strain caused by the different temperature expansion coefficients of the conduction medium and the membrane can be used either to increase the pre-strain and thus, for example, achieve systoles and pre-strain heights. even higher bulging, 15 or setting the production signal to such a level and polarity that an unwanted prebulge in an unwanted direction caused by different temperature coefficients is at least partially compensated, fully compensated or even overcompensated for, for example, achieve pre-bulge and systoles of a desired size and direction.
In one embodiment, the temperature coefficient of the membrane (eg metal) is greater than a temperature coefficient of the conduction medium (eg piezoelectric ceramics) and the production signal is such that the conduction medium 25 is in a contracted state during power on. In this case the pre-strain caused by both effects is of the same type (compression of the conduction medium) and increases the achievable pre-stressing (pre-compression) and, depending on the mechanical fixation of the membrane and/or the conduction medium, also the reachable pre-bulge height.
In another embodiment the temperature expansion coefficient of the membrane (e.g. silicon) is less than a temperature expansion coefficient of the conduction medium (e.g. piezoelectric conduction medium) and the production signal is such that the medium The conduction is in a contracted state during switching on and the pre-stress caused by different temperature expansion coefficients is more than compensated by the pre-stress caused by the production signal.
Alternative embodiments may use laser bonding or other bonding technologies to bond the driving means to the membrane and apply the production signal during bonding as described above to achieve bend driver pre-strain and potentially a pre-bulge.
The realizations of the method for manufacturing can be easily implemented due to existing bonding processes and technologies can be used. Only means for applying the production signal to the conduction medium during the connection step of the conduction medium to the membrane must be provided. This is further facilitated according to the way in which the production signal is applied to the driving medium, it may be the same way in which the operating signal is applied. For piezoelectric actuators, for example, the same electrical connections used to apply the operate signal to the piezoelectric actuator during normal operation (later in the field) can also be used to apply the production signal during manufacturing or production.
In the following, micropump embodiments comprising a bend transducer embodiment are described, wherein the membrane of the bend transducer forms the membrane of the pump.
Figs. IB and 1C show a schematic sectional view of an embodiment of the micropump comprising a pump membrane 110, a pump body 120 and a passive inlet check valve 130 and a passive outlet check valve 140. Fig. 1B shows a cross-sectional view of a first embodiment in a first curved position. Fig. 1C shows the realization of the micropump in the second less curved position. In Fig. 1B the driving means which is adapted to drive the pump membrane from the first curved position to the second less curved position is not actuated. Therefore, the driving means (also conductive or driver; not shown in Fig. 1B) can also be referred to as being in a non-actuated state, non-activated state, inactive state or resting state, and this position or status of the micropump and pump membrane can also be referred to as non-triggered, idle, or rest position or status. In Fig. 1C the driving means (not shown in 1C) is activated or activated and has moved the pump membrane 110 to the second position. Therefore, in relation to the conduction medium, the pump membrane and the micropump, this status or position can also be referred to as activated or activated status or position.
The pump membrane 110 has a first surface or upper surface 112 and a second surface or lower surface 114 that is arranged opposite the first surface 112. The pump body 120 may comprise a first surface or upper surface 122 and a second surface or surface lower 124 which is arranged opposite the first surface 122. The pump membrane 110 is connected at its circumference to the pump body 120, wherein the pump chamber 102 is defined as the space or volume between the pump membrane 110 and the pump body. pump 120. The pump body 120 comprises an inlet 126 and an outlet 128 (pump inlet/pump outlet) and a cavity in the upper side of the pump body, i.e. the side facing towards the pump membrane 110, wherein the first valve 130 and the second valve 140 are arranged. First valve 130 and second valve 140 have a fluid connection, for example a direct fluid connection, to pump chamber 102.
Fig. 1B shows an embodiment of the micropump 100, wherein the inlet check valve 130 and the outlet check valve 140 are provided as a stack 170 of two semiconductor chips 150 and 160, wherein the upper semiconductor layer or chip 150 of the double valve structure 170 is arranged on top of the lower semiconductor layer or chip 160, and wherein the upper semiconductor layer 150 has been mechanically structured to provide a butterfly valve for the inlet check valve and valve seat for the outlet check valve 140, and the lower semiconductor layer 160 have been structured to provide a valve seat for the inlet check valve and the outlet check valve butterfly valve. The first and/or second semiconductor layer 150 and 160 can comprise silicon or other semiconductor materials. Further details on layered valve structures are described, for example, in US 6,261,066 B1. Other embodiments may comprise other inlet and outlet valves, for example active inlet or outlet valves, and may comprise materials in addition. of semiconductor materials, eg metals or polymers.
As can be seen from Figs. IB and 1C, the first surface 122 of the pump body 120 is flat and an upper surface of the inlet and outlet check valve 130, 140, or in other words, an upper surface 152 of the upper layer 150 facing the pump membrane. 110, is also flat and at the same height level with respect to a vertical orientation of Fig. 1B as the first surface 122. Below this common plane (defined by surfaces 152, 122), the inlet check valve 130 comprises cavities 132 , for example, cavities within the top and bottom layer 150, 160, and the outlet check valve 140 comprises cavities 142, for example, within the top layer 150, which are also referred to as "valve wells" 132 and 142.
Although Figs. IB and 1C show a pump body 120 with a double valve structure 170, other micropump embodiments may comprise valve structures 130 and 140 structured directly within the pump, or in other words, valve structures 130 and 140 directly integrated into the material of the pump body 120.
In other embodiments, upper surface 152 of valve structure 170 can already form pump body 120 (see, for example, Figs. 4A-4F and 5A-5B).
In the following, the first surface 122 of the pump body 120 and the upper surface 152 of the inlet and outlet check valves 130 and 140 will also be together referred to as the first surface of a pump body or the base of the pump chamber. Thus, the micropump 100 according to Figs. IB and 1C comprises a first essentially flat surface 122 or base of the essentially flat pump chamber, i.e. a first surface which is flat except for the wells 132 and 142 of the valve wells.
Within this context it should be mentioned that the maximum volume Vmax of the pump chamber 102 comprises the volume between the pump body 120 and the pump membrane 110 as shown in Fig. IB (in the pre-bent state) and the volumes of the wells. valve 132 and 142. As can be seen further from Fig. 1C, in embodiments where the pump membrane 110 assumes a flat shape within the second, less curved position, and bears the first surface 122 of the pump body 120, the dead or minimum volume V0 is essentially defined by the volumes of the valve wells 132 and 142. The difference between these two volumes is also referred to as the stroke volume ΔV, ie ΔV = Vmax - Vo. As the compression ratio c is defined as c = ΔV/V0, the micropump realizations according to Fig. 1B-1C provide high compression ratios.
As can be seen further from Fig. 1B, the reference sign H refers to the height of the pump chamber in the non-actuated state, i.e. the vertical distance between the first surface 122 of the pump body and the lower surface 114 of the pump diaphragm at the center 104 of the pump diaphragm. The diameter D of the pump or micropump chamber is defined by the distance between two opposite lateral positions of the micropump in which pre-bent state not actuated - the pump membrane 110 touches the pump body, which typically coincides with the positions according to the membrane pump 110 is connected on its circumference to pump body 120.
The pump chamber 102 is completely sealed from the environment (except for the inlet check valve 130 and the outlet check valve 140) through a connection between the pump membrane 110 and the pump body 120 at the circumference of the pump membrane 110. The circumference of the membrane of the pump 110 can have an angular shape, any point of symmetrical geometric shape, or any other shape. The point of symmetrical and angular circles provide improved pumping characteristics as they avoid distortions during movements.
Fig. 1D shows a schematic sectional view of the pump membrane 110 in the previous intermediate state 110' when moving from the second flat state to the first pre-curved state (see arrow A). When the driving means is no longer actuated, the pump membrane 110 begins to resume the pre-bent state. The upward movement of the pump membrane 110 starts, for example, at the center 104 of the pump membrane forming the small bulge shown in Fig. 1D which increases in height (see arrow A) and extends laterally (see arrow B) to finally reach the fully pre-curved position as shown in Fig. 1B. A typical problem with micropumps is that the pump membrane 110 tends to adhere to the pump body 120 as it rests on the pump body 120. The inlet check valve arrangement 130 and the stick effect check valve due to the valve wells formed by these valves. Other embodiments comprise inlet valves 130 and outlet check valves 140 which are arranged in a central area 126 extending from the center of the membrane and the corresponding center of the pump body 120. As can be seen from Fig. 1D, such central arrangement of the inlet check valve and the outlet check valve with their corresponding valve wells allows for easier formation of the initial camber shapes 110' as shown in Fig. 1D and thus further reduces the adhesion effect. The diameter of the center area 126 can be in the range of less than 70% of the diameter D, less than 50% or less than 30% of the diameter D of the pump chamber 102.
For micropump realizations that move the pump membrane 110 between the first pre-curved position, for example, as shown in Fig. 1B, and a second flat position, as, for example, shown in Fig. 1C, the height H of Pump chamber 102 also represents systole distance or systole height.
The pump chamber volume Vmax and the stroke volume ΔV can be increased by increasing the pump chamber diameter D and/or by increasing the systole height H. As will be described later, the realizations of the micropump production method allow to produce micropumps with large diameters D, high systolic heights H and high proportions between systolic height H and pump chamber diameter D.
The embodiments of the micropump, or the bending transducer in general, and methods for producing the micropump may comprise one or more piezoelectric conduction means, for example monomorphic piezoelectric elements, multilayer piezoelectric elements or piezoelectric stack elements, or any other means a driving signal that is adapted to laterally contract a certain driving signal, also referred to as an operate signal or trigger signal, or a production signal is applied thereto. These conduction signals can be conduction voltages (e.g. the piezoelectric conduction medium), conduction currents, or any other physical measures suitable for driving the conduction medium. The same applies to production signals.
Figs. 2A and 2B show schematic sectional views of an embodiment of the micropump 200 comprising a piezoelectric drive element 210 connected to the top 112 of the pump membrane 110. Fig. 2A shows, analogous to Fig. IB, the micropump with the pump membrane 110 in the first pre-curved position and Fig. 2B the same in the second less curved position, in this case the flat position. The piezoelectric conduction element 210 comprises an upper electrode on the first surface 212 (also top or top surface) and a bottom electrode on the second surface (also bottom or bottom surface) of the piezoelectric conduction element 210, wherein the second surface 214 is arranged on the main surface opposite the piezoelectric drive element 210 (electrodes not shown). The upper electrode of the piezoelectric conduction element 210 is typically connected to a first contact 216 and the bottom electrode of the piezoelectric conduction element 210 is electrically connected to a second contact 218 of the micropump, for example, through a conductive coating arranged at least on a part of the first surface 112 of the pump membrane. The piezoelectric drive element 210, for example, can be secured to the membrane of the pump 110 by glue or other bonding techniques. The piezoelectric conduction element is polarized so that in case of a positive voltage is applied between the top electrode 216 and the bottom electrode 218, respectively the first contact 216 and the second contact 218, the piezoelectric conduction element contracts laterally , and thus bends the pre-curved pump membrane 110 under the pump body 120. In Fig. 2A no voltage (U = 0) is applied to the electrical contacts 216, 218. In other words, the piezoelectric conduction element is not engaged and the pre-curved pump diaphragm 110 assumes its pre-curved position. In Fig. 2B a positive voltage, eg U = Umax, is applied so that the membrane 15 of the pump 110 is bent downward to the flat pump body 120 and rests on the latter.
Preferred micropump embodiments are based on the idea that a pump membrane or driving membrane is attached over an essentially flat pump chamber base 20, or a pump chamber base comprising a slump that is less than the height of pre-bulging H of the pump diaphragm in the upward direction, wherein the pump diaphragm is pre-curved upwards and the valve unit 170, e.g. valve structure 130, 140, is comprised within the base of the chamber. of the pump. The distorted or pre-distorted (ie, pre-curved) membrane can be distorted or moved towards the base of the pump chamber so that the pump membrane rests flat on the base of the pump chamber (see Figs. 1C and 2B ). The dead volume Vo, is thus essentially only defined through the remaining dead volumes of the valve wells 132, 142.
Movement of the pump membrane 110 from the first pre-curved position to the second flat position can be achieved in a number of ways, for example through piezoelectric ceramic 210 or other piezoelectric conductors, for example piezoelectric cell drivers, glued to the top of the pump membrane, as discussed based on Figs. 2A and 2B, contracting laterally when positive stress is applied, relaxing laterally when no stress is applied, and expanding beyond the lateral length or dimension of the relaxed state when negative stress is applied.
In other embodiments, the emission of force on the membrane of the pump to bend is applied through a piezo-cell driver that is permanently attached to the membrane of the pump.
Silicon microvalve valve wells according to, for example, US 6,261,066 B1 comprise a remaining dead volume of about 360 nanoliters (0.36 microliters). A pump membrane with a pre-curved shape similar to a curved shape of the pump membrane, eg of a micropump, according to US 6,261,066 Bl, with a diameter D of 30 mm, allows to generate a volume systolic of about 22 microliters. Therefore, the compression ratio c is 22/0.36 = 61. This compression ratio is multiple times higher than the compression ratios of known micropumps that are within a range of 0.1 - 1.0. By optimizing a compression ratio that can be further increased as the above mentioned silicon micropump valves can be further optimized in relation to their dead volume. Thus, it is, for example, possible to produce silicon valves with a remaining dead volume of about 50 nanoliters. By increasing the pump chamber the stroke volume can be increased, for example, by 50 microliters. Thus, a compression ratio of 50 microliters/50 nanoliters = 1000 can be achieved. In combination with a correspondingly strongly sized piezoelectric conductor, micropumps can be provided that are capable of either creating high negative pressures that are close to vacuum conditions, or to create very large positive pressures of several hundred bars.
In the following, the embodiments of the production methods 15 of the inventive micropump embodiments are described.
An example of a method for producing the micropump which can be combined with a method according to Fig. 1A will be described based on Figs. 3A and 3B. According to the example, the conduction means, e.g. a piezoelectric conduction means 20, is held on top of the pump membrane and the pump membrane is pre-curved due to different temperature expansion coefficients of the piezoelectric conductor and the pump membrane. The pump membrane 110 is, for example, already secured on the pump body 120, the pump body, for example, already comprising at the inlet check valve 130 and the outlet check valve 140. The base of the chamber The pump can, for example, as shown in Fig. 3A, be flat or at least essentially flat attached to the pump body in a flat shape. In addition to the above-mentioned structure comprising the pump body and the pump membrane, the conducting means, for example the piezoelectric conductor, is provided and arranged on top of the pump membrane 110 with a layer of glue 320 between the piezoelectric conductor 210 and pump membrane 110. Glue 320 may, for example, be placed on the lower surface of the piezoelectric conductor or on the upper surface of the pump membrane. The piezoelectric conductor is pressed at a predetermined production pressure, for example using a silicon seal 310, onto the pump membrane to evenly distribute the glue and achieve a thin glue layer 320. The glue is stiffened in increased output or the connection temperature Tpr0duction-
Heating of the pump body 120, the pump membrane 110 and the piezoelectric conductor 210 can be started before the piezoelectric conductor 210 is mounted on the pump membrane 110, or after the piezoelectric conduction means has been positioned (including the glue) on top of the pump membrane 110, however, the hardening of the glue is carried out at the production temperature TProduction •
After hardening of the glue of the pump device (comprising the pump body, the pump membrane and the piezoelectric conduction means) it is cooled. As the temperature expansion coefficient of the piezoelectric conduction element (i.e., of a material that the piezoelectric conduction element comprises or consists of), for example, a piezoelectric ceramic, is only less than the expansion coefficient of the material that the pumping membrane comprises or consists of), the contraction of the pump membrane is greater than the contraction of the piezoelectric conductor attached to the top of the pump membrane, and thus the drive unit comprising the pump membrane and the piezoelectric conductor is curved to top (when the piezoelectric conductor is not engaged).
Micropumps, according to the example of the micropump production method, may, for example, comprise pump membranes with metals or metal alloys as pump membrane material, for example, with temperature expansion coefficients in a range of 10 to 25 times 10'6/K at 20° Celsius, or synthetic materials and/or polymers, for example, with temperature expansion coefficients in a range of 10 to 250 times 10'6/K at 20° Celsius, and piezoelectric conductors, eg piezoelectric ceramic conduction elements, eg with temperature expansion coefficients in a range of 2 to 7 times 10“6/K at 20° Celsius.
The temperature expansion coefficient of the pump membrane may be more than five times higher or more than ten times higher than the temperature expansion coefficient of the driving medium. The higher the above mentioned ratio between the temperature expansion coefficient of the pump membrane and the temperature expansion coefficient of the conduction medium, the higher the extent to which the pump membrane 110 is prebent, and thus, the highest the height H, the systolic height H, the stroke volume ΔV, and finally the compression ratio. membrane 110 and the hardening of the glue at the production temperature can be carried out after the pump membrane has been connected to the pump body (as described above) or before the connection of the membrane to the pump body is carried out.
Fig. 3A shows the bonding of the piezoelectric ceramics 210 on top of the pump membrane 110, the application of production pressure (see arrows 312) in Fig. 3A through a silicone seal 310, and the hardening of the glue 320 in the production temperature Tpr0du 3o- Fig. 3B shows the pre-curved membrane 110 which is pre-curved due to the different temperature expansion coefficients after the pump has cooled (glue not shown in Fig. 3B).
An embodiment of a method of producing a micropump according to Fig. 1a will be described on the basis of Figs. 4A to 4F. Figs. 4A to 4F show schematic sectional views of a production of a micropump with a pre-curved pump membrane, wherein the two-layer valve structure 170, for example, described in context with Fig. 1B, forms the body of the pump 120, and wherein the pump membrane is provided as a thinned and structured third layer 410.
As can be seen from Fig. 4A, the third layer 410 is thinned in a central area of its first surface or upper surface 412 to provide a flexible pump membrane 110. As can be seen further from Fig. 4A, the third layer 410 was also lightly thinned on the second surface or lower surface 414 arranged opposite the first surface 412 and another central area or region having a diameter, for example, greater than the diameter D of the central area. A pump membrane 110, respectively, the third layer 410 and the pump body 170 are connected together so that the pump chamber 102 is defined between the pump body and the pump membrane.
In other embodiments, the third layer may comprise a second plane or lower surface 414 (i.e., no cavity in the central area in the region of the pump chamber, or in other words, no spacing structure on the circumference of the lower surface of the third layer or an equivalently spaced structure at the top surface of the pump housing) so that the pump membrane 110 rests in the center of the pump housing to the upper surface or base of the pump chamber before pre-bulging is performed. The remaining dead volume from such embodiments is essentially only defined across valve wells 132 and 142.
The production of such layered pump structures is, for example, described in US 6,261,066. The three layers 150, 160 and 410, for example, comprise semiconductor materials, for example, silicon or other materials.
In other words, in Fig. 4A the micropump before pre-bulging and before bonding the piezoelectric ceramics to the membrane is shown.
In Fig. 4B the piezoelectric ceramics 210 with a layer of glue 320 on its bottom surface is placed on the top surface 412 of the membrane 110.
Fig. 4C shows the micropump structure with the piezoelectric ceramics 210 positioned on the membrane 110 and the glue layer 320 between the piezoelectric ceramics and the pump membrane.
In Fig. 4D the piezoelectric ceramic 210 is pressed at a predetermined production pressure onto the membrane of the pump 110, for example using a silicone seal 310. The production pressure is such that the glue 320 is preferably essentially evenly distributed over the connecting surface of the piezoelectric ceramic and the pump membrane and provide a thickness of the glue layer that is small enough to allow peak contacts between the conductive layer on the top surface of the membrane and the bottom electrode of the piezoelectric ceramic, to electrically connect both. Peak contacts allow you to use insulating or non-conductive glue to bond the piezoelectric conduction medium to the pump membrane and further electrically connect the bottom electrode of the piezoelectric conduction medium. It should be mentioned that in the steps represented by Figs. 4C and 4D the glue is not yet hardened.
In Fig. 4E a production voltage Uproduction is applied to the piezoelectric conduction medium 210 (eg, piezoelectric ceramic or piezoelectric cell driver) so that the piezoelectric conduction medium contracts. After contraction 20 or shrinkage of the piezoelectric conductor the glue is stiffened while applying a production voltage UprOduction θ also maintaining the production pressure through the 310 silicon seal.
After the glue has hardened, the production tension and pressure are released.
In other words, the piezoelectric ceramic is glued onto the pump membrane, whereby during the hardening of the glue a positive production voltage is applied to the piezoelectric conduction element. Thus, the middle pottery of J| piezoelectric conduction contracts and is membrane-bound in the contracted state. The production tension is only released after the glue has hardened.
After the tension has been released, the piezo ceramic 5 either relaxes or extracts again, thus causing the drive unit (ie pump membrane and piezo ceramic) to pre-bulge as shown in Fig. 4F (glue not shown in Fig. 4F).
Thus, the pump structure of Fig. 4A has been modified to comprise a pre-strained or pre-curved membrane or diaphragm. Depending on the pump chamber volume and dead volume, such realizations can reach high compression ratios as explained above.
Although an embodiment of the micropump production method has been described with the membrane 410 already attached to the pump body 170, in the alternative embodiments the pre-bulging (i.e., the positioning of the piezoelectric ceramic and the stiffening of the glue at the tension of production) can also be carried out before the pump membrane or third layer is attached to the pump body.
Fig. 5A shows a schematic cross-sectional view of the micropump produced by the method according to Figs. 4A to 4F. Fig. 5A shows the micropump with pre-bent membrane 110 in an unpowered state (U=0V). Fig. 5B shows the micropump of Fig. 5A in an actuated state, where the pump membrane 110 has an essentially flat shape. The pump membrane 110 can, for example, be moved to the second flat position by applying an operating voltage U which is equal to the production voltage Uproduction, eg 300V, in case no back pressure or back pressure is applied. In case back pressure is applied, the operation or drive voltage U can be increased to voltage values higher than the production voltage Uproductioni to create sufficient pressure within the pump chamber to overcome the necessary threshold pressure difference at which the Outlet check valve 140 opens and a fluid inside the pump chamber can be pumped out of the micropump.
As previously mentioned the method as described on the basis of Figs. 4A to 4F can also be combined with a method as described based on Figs. 3A and 3B and provides another embodiment of a method for producing a micropump, and also allows to achieve pre-bulge of the membrane of the pump.
In the above-mentioned embodiment the pump membrane is pre-extended by means of conduction, due to the different coefficients of thermal expansion and/or due to the extraction of the piezoelectric conduction medium after the production voltage has been released. Thus, when the driving means is actuated and bends the pump diaphragm, the tension of the pump diaphragm due to the extension is partially or completely released, for example when the pump diaphragm is in the second flat position.
Micropump embodiments using piezoelectric conduction means, eg piezoelectric ceramics, i.e. piezoelectric cells, provide - compared to electromagnetic or electrostatic conduction means - large systole forces and systole lengths or heights at comparably low voltages.
To reduce the sticking effect or to prevent the pump diaphragm from sticking to the pump body when the pump diaphragm rests on the pump body, such as star-arranged recesses extending radially, for example from the non-return valve of inlet or the respective valve well can be arranged, or small shafts or protrusions extending from the base of the pump chamber or the pump membrane in the pump chamber can be implemented.
Although predominantly micropump embodiments have been described to comprise inlet check valves and outlet check valves 130 and 140 made of semiconductor materials, e.g. silicon, other micropump embodiments may comprise passive inlet and outlet check valves different or similar ones comprising different materials, for example metals or polymers independent of the pump body, are integrated therein.
Furthermore, although micropump embodiments have been described to comprise inlet check valves and outlet check valves 130 and 140 integrated or arranged in the pump body, alternative embodiments may comprise valves which are arranged, for example, laterally between the pump diaphragm and the pump body.
Still other embodiments of the micropump may comprise a pump body in which the inlet and outlet check valves are integrally formed, as, for example, was described based on Figs. 4A to 5B.
Still other embodiments may comprise pump bodies with integrally formed valve outlet and valve inlet structures 130 and 140 comprising materials such as steel, stainless steel or stainless steel spring, synthetic materials or polymers, wherein the pump bodies may comprise a or multiple layers to form the valve structures. Therefore, other micropump embodiments may comprise pump bodies and pump membranes of metals, synthetic materials or polymers, or stacked structures thereof. Compared to silicon pump bodies and pump membranes, pump bodies and pump membranes made of metals or polymers are less costly in production and provide greater flexibility and, for example, lower Youngs modules.
Other embodiments of the invention provide a micropump with a conductive membrane, in which the conductive membrane moves between a pre-distorted or pre-curved upward position and an essentially flat position, in which the uneven sections on the arranged surface face the membrane of the pump. of the pump body are less than a systolic height H of the membrane.
Such micropumps can comprise conductive membranes that are pre-curved in the upward direction. Such embodiments may comprise piezoelectric ceramic bonded over the conductive membrane.
Such micropump embodiments may further comprise a membrane moved between two positions via a piezo cell driver, wherein the membrane is permanently attached to the piezo cell driver.
The following are the results of various simulations of other aspects and/or advantages of the embodiments of the present invention.
Pump membrane bend shapes were calculated for a silicon piezoelectric pump (a micropump with a pump membrane comprising or consisting of silicon and a piezoelectric conduction medium as the conduction medium) using finite element analysis. For the micropump geometry, the following parameters were used: a quadratic silicon pump membrane with a side length of 6.3 mm and a thickness or height of the pump membrane itself of 50 mm, a piezoelectric conduction means with a thickness or height of 150 mm, where the proportion of the side lengths of the piezoelectric conduction means is 0.8 relative to the side lengths of the pump diaphragm. The bend shape is shown parallel to axis 15 through the center of the diaphragm from the center to the edge of the diaphragm of the pump.
Pump membrane bend shapes were calculated for a silicon piezoelectric pump (a micropump with a pump membrane comprising or consisting of silicon 20 and a piezoelectric conduction medium as the conduction medium) using finite element analysis. For the micropump geometry, the following parameters were used: a quadratic silicon pump membrane with a side length of 6.3 mm and a thickness or height of the pump membrane itself of 50 mm, a piezoelectric conduction means with a thickness or height of 150 mm, where the proportion of the side lengths of the piezoelectric conduction means is 0.8 relative to the side lengths of the pump diaphragm. The bend shape is shown parallel to the axis through the center of the diaphragm from the center to the edge of the diaphragm of the pump.
Different characteristic bend shapes were determined for cases where the formation of the bend shape is caused by (la) only through thermo-mechanical stresses caused by different temperature expansion coefficients of the materials used, (1b) only through the driving effect of bending through the application of an electric field to the piezoelectric conduction medium, (2) only the effect of an application of a pressure (pressure difference between the lower and upper side of the pump membrane), and (3) only the bending trigger effect due to an oxide layer structured with intrinsic stress (structure: oxide layer instead of the piezoelectric conduction medium in the same position).
Cases (la) and (1b) are identical with regard to their effect and characteristic fold shape and will be summarized as "U/T" case. Case (2) will be referred to as case "P" and case 3 will be referred to as "Ox". In Fig. 6, the fold shapes of these three aforementioned "pure cases" are shown in a normalized manner, that is, the height z scaled to the maximum fold value z0 for the corresponding case and the lateral position x scaled to length x0 of the silicon membrane. At the bottom of the diagram in Fig. 6, the pump membrane 120 with the length x0 (from the center to the edge) is shown and the length of the piezoelectric conduction means from the center to 0.8 of the membrane length pump is shown (side length ratio 0.8). In Fig. 6, reference signal 610 refers to case U/T, reference signal 620 to case P, and reference signal 630 to case Ox. Fig. 6 shows the normalized bend shapes for half of the pump membrane (from center to edge) for different bending cases or effects.
In a first estimate, all these effects 5 of temperature, pressure and oxide stress in relation to the bend (bend shape) and displaced volumes are linearly scalable and linearly over-positionable.
Next, pump membrane folding and displacement volumes or stroke volumes are discussed in relation to their absolute values. The parameters for the simulation are, for the silicon membrane: lateral area or surface of 6300 x 6300 mm2, a thickness of 50 mm, a Youngs modulus of 166 GPa (Poisson value 0.3), and for the conduction medium piezoelectric: width and lateral length of the piezoelectric conduction medium 15 being 0.8 of the lateral length and width of the silicon membrane, a thickness of 150 mm, a Youngs modulus of 90 GPa (Poisson value 0.3). The temperature expansion coefficients α being for silicon 0.3 x 10"6/K and for the piezoelectric conduction medium 5 x 10"6/K (difference of 2.7 x 10"6/K). The coefficient 20 d31 of the piezoelectric conduction medium being 330 x 10-12 m/V.
Fig. 7A shows a diagram of the fold shape of a prior art pump membrane from center (left side of diagram) to edge (right side of diagram) with lateral dimension x normalized to half length or width x0da pump diaphragm and the vertical dimension z shown as an absolute value in micrometres. Fig. 7A shows the bend shape at 20°C and -50 V (reference signal 712) at 0 V (reference signal 714) and at 150 V (reference signal 716) without pressure (P = 0) at if the piezoelectric conduction means has been mounted or armed at 80°C without applying a production voltage (Uproduction = 0). Among Figs, the abbreviation "w." is used for "with" and the abbreviation "wo" for "without"...
As can be seen from Fig. 7A, in case the connection of the piezoelectric conduction means to the pump membrane is carried out by hardening the glue at 80°C, a measurement at room temperature (20°C) already leads to a temperature difference of -60°C, and thus to a membrane fold of the pump 10 down by 5 μm. In other words, due to the fact that the temperature expansion coefficient of the silicon pump membrane is less than the temperature expansion coefficient of the piezoelectric conduction medium, the piezoelectric conduction medium to the pump membrane doubles in temperature 15 increased production Tproduction causes a pre-bulging of the pump diaphragm in a downward direction (negative z-values) when the pump diaphragm and the piezoelectric conduction medium are cooled, eg to ambient temperature. This pre-bulging of the pump membrane in the downward direction is disadvantageous as it does not allow to use, for example, flat pump chamber bases, increases dead volume and/or needs to adapt the pump chamber base to the bending line of the pumping membrane, which is complex and costly as previously described. Additionally, some pre-bulging in the downward direction is almost inevitable in the case of silicon membranes because silicon membranes have a temperature expansion coefficient lower than piezoelectric conduction and glues used to bond the conductor at temperatures higher than the temperatures of normal operation or environment.
As mentioned earlier, in case the temperature expansion coefficient of the pump membrane is 5 higher than the temperature expansion coefficient of the piezoelectric conduction medium, the pump membrane is pre-curved in the opposite direction, i.e. upward direction after cooling of the pump membrane and that of the piezoelectric conduction medium to, for example, ambient temperature. Thus, the membrane of the pre-curved up or positive pump 10 can easily be produced without requiring additional processing steps, for example, additional oxide layer formation.
The shape of the bend 714 can be thought of as the shape of the bend that the pump membrane assumes when the driving means is not actuated and no other external pressure or influence is applied to the pump membrane. As can be seen from Fig. 7A, the height z (or H) is about -5.35 µm at the center of the pump membrane. In case a negative conduction voltage of -50V is applied (see reference signal 712) the pump diaphragm is deflected in an upward direction, due to the piezoelectric conduction medium expanding, and in case of a positive voltage of + 150 V is applied as a conduction voltage, the pump diaphragm bends further down (see reference signal 716) due to contraction of the piezoelectric conduction medium.
By applying a voltage, eg a production voltage UPrOduction to the piezoelectric conduction medium during the temperature switch-on shown in Fig. 7A (the downward bending of the pump membrane) it can be counter-driven, partially compensated, fully compensated or even over-compensated depending on the production voltage applied during connection. To compensate for a temperature difference of 60°, for example, in case the connection of the piezoelectric conduction means to the pump membrane is carried out at 80°C and the micropump is operated or used later at 20°C, a voltage production power of 73.6 V is needed to compensate for the negative pre-bending caused by the temperature difference of 60°C, ie to obtain a flat shape in case the conduction medium is not activated. As the bend shapes are identical (ie, normalized identical), the systole and volumes are compensated at the same time and the pump membrane again assumes a flat shape when no external pressure and stress is applied.
Fig. 7B shows a diagram of the half pump membrane bend shapes from the center to the edge for a piezoelectric connection to the pump membrane at 80°C and a production voltage of 73.6V (in one representation similar to Fig. 7A). Reference signal 722 shows the pump diaphragm bend shape at 20°C and a conduction voltage of -50 V without external pressure P. Reference signal 724 shows the pump membrane bend shape at 20° C and 0 V (no production voltage) and no external pressure and the reference signal 726 shows the pump membrane bend shape at 20°C and a driving voltage of 150 V at an external pressure P. How can it be seen from Fig. 7B, switching on the piezoelectric conduction means at 80°C and applying, during switching on, the production voltage of 73.6 V, the downward or negative pre-bending caused by the temperature difference of - 60°C and the rising or positive pre-bending releasing the production voltage compensate each other so that the pump diaphragm assumes a flat shape (see reference sign 724) when the piezoelectric conduction means is not actuated. As already explained on the basis of Fig. 7A, an application of a negative voltage to the piezoelectric conduction means causes the pump membrane to be deflected upwards (see reference sign 722), whereas an application of a positive voltage causes that the pump membrane curves downwards (see reference signal 726).
Fig. 7C shows a diagram similar to that of Fig. 7B (for the same pump membrane as in Fig. 7B). The two top fold shapes are identical. The reference signal 728, however, refers to the bend shape resulting from the application of a driving voltage of 150V and an external pressure of 1 bar. As can be seen, the application of a driving voltage of 150 V causes the pump diaphragm to deflect downward despite a back pressure P of 1 bar being applied to the pump diaphragm.
Next, it is exemplarily calculated which voltage should be applied during the connection of the piezoelectric conduction medium to the pump membrane (at 80°C) so that the pump only touches or rests on a certain back pressure and a conduction voltage 150 V on the upper surface of the pump body. The pressure must be that which follows the ratio of the resulting compression.
Fig. 7D shows a diagram with the shapes of the
Figs. 7A to 7C, however, for a pump membrane, where the connection of the piezoelectric conduction medium was carried out at 80°C at a production voltage of 178V. Reference signal 732 refers to the pump diaphragm bend shape from the center to the edge of the pump diaphragm at 20°C and -50 V without pressure. The reference signal 734 refers to the membrane bending shape of the pump in a non-driven state (the driving voltage U = 0V) and without the external pressure (P = 0) . The reference signal 726 refers to the same pump membrane (pre-bend by connecting the piezoelectric conduction means at 80°C and 178 V) when a production voltage of 150 V is applied to the piezoelectric conduction means and the counter pressure of one bar is applied to the pump's membrane. As can be seen from Fig. 7D, the higher production voltage of 178 V of Fig. 7D compared to the production voltage of 73.6 V of Figs. 7B and 7C pre-bulge the thick silicon pump membrane in the downward direction even though the temperature expansion coefficient of the silicon pump membrane is less than the temperature expansion coefficient of a piezoelectric material of the piezoelectric conduction medium , i.e. the pre-bulging of the pump membrane downwards due to the different temperature coefficients is over compensated by the application of the production voltage. With these production parameters, a pre-bulge height of approx. 7.5 μm can be reached in the center of the pump diaphragm. In case a negative conduction voltage is applied (see reference sign 732), the pump diaphragm is deflected upwards, whereas in case a positive conduction voltage is applied, the pump diaphragm is deflected 736).
As can be seen, the pump membrane rests on the base of the pump chamber or the pump body despite a back pressure of one bar being applied. Back pressure P causes a slight deflection of the pump membrane at the edge. In case no back pressure is applied (P = 0 mbar), the pump diaphragm will rest completely on the base of the pump chamber, because the pre-bulge is adapted to the deformation caused by the actuation of the piezoelectric conduction means. The remaining dead volumes below the diaphragm of the 736 pump are about 11.5 nL and occur only in the case of the counter pressure mentioned above. However, these dead volumes are small compared to the total stroke volume (the volume between the 732 and 736 format of the pump membrane) of about 163 nL.
Summarizing the above, the embodiments of the method for producing the pre-bent pump membrane offer a wide variety of combinations of pump membrane materials and conduction means, e.g. piezoelectric conduction means, and allow to flexibly adjust the parameters of production, for example, production signal, production voltage and/or production temperatures to meet predetermined operating parameters that the micropump must fulfill, for example, systolic height, stroke volume, compression ratios, against pressures.
Embodiments of the method for producing the pre-bent pump membrane using a production signal to contract the driving means and turn the driving means in the contracted state another signal value or voltage value can be used as an output value or a production tension. Thus, almost any pre-bulge height, systolic height and stroke volume can be achieved.
In the case where glues are used to bond the conduction medium to the pump membrane, the glues typically have a specific production temperature of the glue at which they are to be hardened. These production temperatures are typically higher than ambient temperature. Depending on the magnitude of the production temperature and the difference between the production temperature and the operating temperature of the micropump or, in general, the edge transducer, it is used later during normal operation, pre-stressing and potentially pre-bulging of the membrane of the pump and the driving medium are inherently caused in case the driving medium and pump membrane have different coefficients of temperature expansion. By selecting the appropriate conduction medium and pump membrane materials, eg the respective piezo ceramic and steel or synthetic materials for the membrane, the pre-stressing effect caused by the different temperature expansion coefficients can be used to increase pre-tensioning and potentially pre-bulging of the pump diaphragm. The same considerations apply to other bonding methods using bonding materials, eg solder.
A consideration of both effects still allows using pump membrane materials with lower temperature expansion coefficients than the conduction medium of silicon pump membranes, although they normally cause a pre-bulge in the downward direction. However, by additionally applying an appropriate production signal or production value, the pre-bulge in the downward direction can be more than compensated for to finally reach a pre-bulge in the upward direction.
In other words, in certain embodiments a second thermal expansion coefficient (thermal expansion coefficient of the conduction medium comprising a second material) is higher than a first thermal expansion coefficient (thermal expansion coefficient of the membrane comprising a first material) and the production signal is such that a pre-bulging of the pump diaphragm in a first direction effected by releasing the production signal more than offsets a pre-bulging of the pump diaphragm in a second direction opposite to the first direction effected by cooling the medium connected conduction and the pump membrane.
Other embodiments of a method of producing the pre-bulged pump membrane therefore comprise determining, for example automatically, based on a predetermined back pressure value at which the pump membrane should assume the second position when the driving means is triggered, the first and second material and/or the production signal value.
Compared to pre-bulging methods using oxide layers on top of piezoelectric actuators, the embodiments of the present invention require less material (no oxide layer), fewer production steps (no piezoelectric conduction), are more flexible with respect to volumes achievable systolic heights and systolic heights, and provides higher systolic heights and withdrawal volumes.
In certain embodiments the middle connection
conduction to the pump membrane is performed so that the pump chamber has a first volume when the pump membrane is in said first curved position and a second volume when the pump membrane is in the second less curved position, wherein the second volume is smaller than the first volume, where the pump membrane, pump body and passive inlet and outlet check valves are arranged so that a compression ratio is greater than 50 or greater than 100, where the proportion Compression is defined by the proportion of a micropump's stroke volume and the second volume, and where the stroke volume is defined by a difference between the first volume and the second volume. The second volume is, for example, essentially defined by a volume of the valve wells within the pump body in passive inlet and/or outlet check valve sections, and/or recesses in the passive inlet or outlet check valves themselves and/or non-stick means adapted to prevent the pump membrane from adhering to the first surface of the pump body when the pump membrane is in the second position.
Alternative embodiments may use laser bonding or other bonding technologies to bond the driving means to the pump membrane and apply the production signal during bonding as described above to achieve bend driver pre-strain and potentially a pre-strain. bulging.
In other embodiments the drive means may be adapted to drive the pump membrane to a third curved position (for example by applying a negative voltage to a piezoelectric drive means) before moving the pump membrane to the second less curved position.
In the following, embodiments of a microvalve comprising a bending transducer manufactured by an embodiment of the present invention are described.
Figs. 7E, 7F, 7FF and 7G show schematic cross-sectional views of a normally closed microvalve 700. Figs. 7E and 7F show the microvalve in a semi-blocking non-actuated state: no operating or driving voltage is applied (U = 0V) and the valve is closed. Fig. 7E shows a side view with the inlet ports, whereas Fig. 7F shows the side view rotated 90 degrees with the outlet ports. Fig. 7FF and 7G show the microvalve in an open state. A positive operating voltage or driving voltage is applied (U > 0V). Fig. 7FF shows the same side view as in Fig. 7E, that is, the side view with the inlet ports (however in an open state) and Fig. 7G shows the same side view as in Fig. 7F , that is, the side view with the exit ports (however in an open state) . The microvalve has a similar design as the microvalves described in US 2004/0036047 A1 and US 2006/0027772 A1. As can be seen from Figs. 7E-7G the 700 microvalve consists of a first chip or driver chip 740 and a second chip or butterfly chip 750. The driver chip 740 comprises a recess or slope 742 on a first main side or surface 744 (top surface according to the Figs 7E-7F) and a recess or slant 743 on an opposite main side 745, and a membrane 110 formed across both the recesses and slants 742 and 743. side of the membrane 110. A shoulder 746 protrudes on a second opposite side 114 of the membrane 110. The first chip 740 further comprises folding caps 748 protruding, like the shoulder 746, from the second surface 114 of the membrane 110. The second chip 750 comprises fluid inlets 752 formed on the second chip (see Figs. 7E and 7FF) and fluid inlets or valve outlets 754 (see Figs. 7F and 7G). Second chip 750 further comprises a flexible plug or closure element 754 that is mechanically connected to membrane 110 via shoulder 746. As can be seen from Figs. 7F and 7G the obturator comprises recesses 756 in a surface facing away from the membrane to allow for a deflection or downward movement in case the driving means 210 is actuated. As can be seen from Fig. 7E, sealing caps 748 fluidly disconnect or seal valve inlets 752 from recess 743, also referred to as valve chamber recess 743, in case the drive means is not actuated. In case the driving means 210 is actuated, the bending transducer formed by the driving means 210 and a membrane 110 bends down and at the same time bends down towards the plug 754 and opens the valve providing a fluid connection between valve inlet 752 and valve chamber recess 743 (see Fig. 7FF). As can be seen from Figs. 7F and 7G, outlet ports 754 are always on the fluid connection to valve chamber recess 740. In other words, by activating conduit means 210, valve inlets 752 are fluidly connected to valve outlets 754 through the valve chamber recess 743.
The first 740 chip and the second 750 chip can be made of silicon or any other material. However, in case the first and second chips 740, 750 are silicon or other semiconductor chips, bonding the driving means 210 using a glue or adhesive requiring a specific production temperature for hardening can lead to unwanted pre-bulging of pump membrane 110 towards plug 754, thus reducing the sealing reliability of normally closed valve 700. The same considerations apply to other bonding methods that effect or require heating of the two chips.
Embodiments of the invention make it possible to compensate or even over-compensate for pre-bulging in the direction of shutter 754 by applying a production signal, for example, a positive production voltage in the case of piezoelectric actuators 210. A pre-stressing of the driving means, by For example, the piezoelectric driving means according to embodiments of the invention has the effect that the microvalve is securely or reliably closed. Already a small pre-stressing of the driving means can be enough to provide a reliably closed valve normally. Additionally, the threshold pressure above which the valve remains closed in the event that back pressure is applied can be easily adjusted by applying an appropriate production signal. An open microvalve typically consisting of a first chip 740 and a second chip 750. The first chip 740 comprises a t recess 742 on a first side 744, so as to form a valve membrane 110. On a first side 112 of the facing membrane 110 away from the second chip 750 the drive means, for example, a piezoelectric drive means 210, is attached to the membrane 110. The drive means 210 and the membrane 110 form a bending transducer. A first chip 740 is connected through a second surface or side 745 opposite the first surface or side 744 to the second chip 750. A second chip 750 comprises a valve inlet 752 formed through a hole extending from one side of the chip. second chip facing the first chip to an opposite side of the second chip, and an output of valve 754 formed similar to the inlet of valve 752 through an orifice extending from the first side of the second chip facing the first chip and the second opposite side or surface. On the first side of the second chip 750 a recession 758 is formed to define a valve seat or valve caps 759.
Driving means 210 has been attached to membrane 110 in accordance with one embodiment of the invention and is pre-curved in a direction facing away from the second chip. Thus, in case the driving means 210 is not actuated, the valve inlet 752 and the valve outlet 754 are in the fluid connection and the valve is open. In case the driving means 210 is actuated, the driving means 210 moves the membrane 110 downwards until it touches the valve caps 759 to seal or close the valve. valve normally open similar to microvalve normally open of Fig. 7H. In contrast to the microvalve of Fig. 7H, the microvalve of Fig. 71 comprises an additional recess 743 on a second side 745 of the first chip and a shoulder 746 protruding from the second side of the valve membrane 110. The shoulder 746 is arranged opposite valve inlet 752 and valve seals 759.
The driving means 210 is connected to the membrane 110 according to an embodiment of the invention and is pre-curved. In case the driving means 210 is not actuated, the inlet of the valve 752 is at the fluid connection with the outlet of the valve 754 due to the pre-curved shape of the membrane 110. In the case the driving means 210 is actuated, the membrane is moved toward the second chip and shoulder 746 rests on valve covers 759 and closes valve.
The embodiments of microvalves as shown in Figs. 7H and 71 having a pre-curved membrane are advantageous with respect to production engineering and also functional advantages. In case the membrane is formed from silicon or other semiconductor materials, no distance element or structure between the valve seat or covers and the closing element (membrane or protrusion) should be provided. Thus, one less mask, one lithograph and one engraving step is required, and thus the production cost and complexity is reduced.
In case the open valve is normally closed, the membrane or shoulder is in a flat condition. In particular, in the case of non-circular valve seats or covers or even in bypass shaped valve seats (used to increase the flow passage) remaining spaces can be avoided which would be present if the membrane was deflected to close the valve. Thus, embodiments of the invention 5 provide microvalves with improved sealing characteristics that are easy to design and manufacture.
The foregoing has been particularly shown and described with reference to particular embodiments thereof. It will be understood by the technicians in the subject that other various changes 10 in form and details can be made without departing from the spirit and scope of this. It is, therefore, to be understood that several changes can be made in adapting different realizations without departing from the broader concept revealed here and understood by the claims that follow.

权利要求:
Claims (17)
[0001]
1. METHOD FOR MANUFACTURING A MICROPUMP, the micropump comprising a transducer with a membrane (110) and a driving means (210), wherein the membrane forms a membrane of the pump and is adapted to be moved between a first curved position and a second position less curved by the driving means; and a pump body (120) connected to the pump membrane so as to define the pump chamber between the pump body and the pump membrane; the method comprising: fabricating the bending transducer (110, 210) by a method characterized by comprising: providing (1010) the membrane (110) and the driving means (210); and applying (1020) a production signal (Uproduction) to the driving means (210) during connection of the driving means to the membrane (110) such that the driving means is pre-stressed after the connection, wherein the production signal is of the same type as an operating signal for operating the bending transducer, so that the pump membrane assumes a pre-curved shape in the first curved position when the driving means is not actuated.
[0002]
2. METHOD, according to claim 1, characterized in that the production signal (Uproduction) is only released after the connection has been terminated.
[0003]
3. METHOD according to claim 1 or 2, characterized in that the connection is carried out by means of a binding material arranged between the conduction means and the membrane, and in which the production signal is only released after the link is stiff.
[0004]
4. METHOD, according to claims 2 or 3, characterized in that the bonding material is a glue or a welding material.
[0005]
5. METHOD according to one of claims 2 to 4, characterized in that it comprises: pressing the conduction means to the membrane (110) during the connection of the conduction means to the membrane, in which the pressing is only completed after the binding material be stiff.
[0006]
6. METHOD according to one of claims 1 to 5, characterized in that the production signal is such that the conduction means (210) is in a contracted state during switching on.
[0007]
7. METHOD according to one of claims 1 to 6, characterized in that the production signal is such that after switching on the bending transducer (110, 210) assumes a pre-curved shape with a pre-bulge in the middle direction. conduction with respect to a connecting surface between the conduction medium and the membrane.
[0008]
8. METHOD, according to one of claims 1 to 7, characterized in that the conduction means (210) is a piezoelectric conduction means and the production signal (Uproduction) is a production voltage.
[0009]
9. METHOD according to one of claims 1 to 8, characterized in that a temperature coefficient of the membrane (110) is greater than a temperature coefficient of the conduction means (210), wherein the connection of the conduction means (210) ) the membrane (110) is performed at a production temperature that is higher than an operating temperature the driving means is further operated and the production signal is such that the driving means (210) is in a contracted state during the call.
[0010]
10. METHOD according to claim 9, characterized in that the conduction means (210) is a piezoelectric conduction means (210) and the production signal is a positive production voltage (Uproduction), and in which the membrane ( 110) comprises a metal or a synthetic material.
[0011]
11. METHOD according to one of claims 1 to 8, characterized in that a temperature coefficient of the membrane (110) is less than a temperature coefficient of the conduction means (210), wherein the connection of the conduction means (210) ) to the membrane (110) is performed at a production temperature that is higher than an operating temperature the driving means is subsequently operated and the production signal is such that a pre-strain of a first type effected by application of the signal production more than compensates for a pre-stressing of a second type, which is the inverse of pre-straining of the first type, effected by different temperature coefficients.
[0012]
12. METHOD according to claim 11, in which the conduction means is a piezoelectric conduction means and the production signal is a positive production voltage (Uproduction), and in which the membrane is characterized by comprising a semiconductor material .
[0013]
13. METHOD according to one of claims 1 to 12, in which the micropump is characterized in that it comprises an inlet check valve and an outlet check valve both in the fluid connection to the pump chamber and arranged in the body of the pump opposite the pump membrane, wherein the pump body (120) comprises a first surface arranged opposite the pump membrane (110) which is essentially flat, and wherein the pump membrane has an essentially flat shape in the second position, such that a pump chamber dead volume is essentially defined by the volumes of the wells of the inlet check valve and the outlet check valve such that a micropump compression ratio is greater than 50, where the ratio Compression is defined as the ratio between the systolic volume of the pump membrane and the dead volume of the micropump.
[0014]
14. MICROPUMP, comprising: a bending transducer comprising a membrane (110) and a driving means (210), wherein the membrane forms a membrane of the pump (110) of the micropump and is adapted to be moved between a first position curved and a second less curved position by the driving means (210); and a pump body (120) connected to the pump membrane (110) so as to define the pump chamber between the pump body and the pump membrane; wherein the pump membrane (110) assumes a pre-curved shape in the first curved position when the driving means is not actuated, and wherein the bending transducer has been manufactured by a method characterized by comprising: - providing (1010) the membrane (110) and the driving means (210); and - applying (1020) a production signal (Uproduction) to the driving means (210) during connection of the driving means to the membrane (110) so that the driving means is pre-stressed after the connection, wherein the output signal is of the same type as an operate signal to operate the warp transducer.
[0015]
MICROPUMP according to claim 14, wherein the micropump is characterized by comprising an inlet check valve and an outlet check valve both in the fluid connection to the pump chamber and arranged in the pump body opposite the pump membrane.
[0016]
The MICROPUMP according to claim 14 or 15, wherein the pump body (120) is characterized in that it comprises a first surface arranged opposite the pump membrane (110) which is essentially flat, and wherein the pump membrane it has an essentially flat shape in the second position.
[0017]
17. MICROPUMP according to claim 14, wherein the micropump is characterized by comprising an inlet check valve and an outlet check valve both in the fluid connection to the pump chamber and arranged in the pump body opposite the pump membrane, wherein the pump body (120) comprises a first surface arranged opposite the pump membrane (110) which is essentially flat, and wherein the pump membrane has an essentially flat shape in the second position so that a pump chamber dead volume is essentially defined by the volumes of the wells of the inlet check valve and the outlet check valve such that the compression ratio of the micropump is greater than 50, where the compression ratio is defined as the ratio between the systolic volume of the pump membrane and the dead volume of the micropump.

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同族专利:

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公开号 | 公开日

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JP2013522512A|2013-06-13|

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EP2542810B1|2015-04-15|

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US20130055889A1|2013-03-07|

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CN102884352B|2014-06-18|

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WO2011107162A1|2011-09-09|

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BR112012022433A2|2017-09-05|

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法律状态:
2019-01-15| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|

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2019-08-06| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|

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2020-08-11| B06A| Notification to applicant to reply to the report for non-patentability or inadequacy of the application [chapter 6.1 patent gazette]|

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2020-12-08| B06A| Notification to applicant to reply to the report for non-patentability or inadequacy of the application [chapter 6.1 patent gazette]|

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2021-04-27| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-06-29| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 05/03/2010, OBSERVADAS AS CONDICOES LEGAIS. PATENTE CONCEDIDA CONFORME ADI 5.529/DF, , QUE DETERMINA A ALTERACAO DO PRAZO DE CONCESSAO. |

优先权:

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申请号 | 申请日 | 专利标题

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PCT/EP2010/052858|WO2011107162A1|2010-03-05|2010-03-05|Method for manufacturing a bending transducer, a micro pump and a micro valve, micro pump and micro valve|

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