JP2004309163A - Liquid feeding module, liquid feeding apparatus, and driving method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid feeding apparatus that has a large liquid feeding flow rate, dispenses with any special sensors, and has high controllability of flow rate and flow velocity. <P>SOLUTION: A liquid feeding module 24 comprises a piezoelectric element 242; a diaphragm 241 that is fixed to the piezoelectric element, where one end can be swung freely; and a voltage supply wire 25 to the piezoelectric element. Additionally, other liquid feeding modules comprise a diaphragm, where a bimorph-type piezoelectric plate is provided on both the surfaces of a metal plate; and a support member, where one end of the diaphragm is fixed and a wire for supplying voltage to the metal plate and the piezoelectric plate is provided. The liquid feeding apparatus comprises a power supply, where a plurality of liquid feeding modules 24 are provided at a channel 23 of a substrate, and voltage is supplied to the pizoelectric element of the liquid feeding module; and a control unit for controlling voltage. Additionally, the liquid feeding module may be arranged so that directions for operating each other are inverted. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to, for example, a liquid feeding device used for controlling the flow of a blood vessel of an artificial heart or a microchannel in a micro total analysis system.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is a liquid feeding device as shown in FIG. 10 (for example, see Patent Document 1).
In the figure, T is a traveling wave generator, 1 is a tube, 3 is an ultrasonic wave generating layer, 9 is a lower electrode, 13 is an upper electrode, and 7 and 11 are films. The ultrasonic microtube 1 has a plurality of traveling wave generating portions T continuous at a predetermined interval. The traveling wave generating portion T has an ultrasonic generating layer 3 made of a piezoelectric material on the outer periphery of the tube 1 and the lower electrode 9 and the upper electrode 9. It is formed between the electrodes 13. In a state where the traveling wave generating portions T are linked, the liquid in the tube 1 moves in one direction by vibrating at a certain frequency between the lower electrode 9 and the upper electrode 13 and generating a high frequency. If the polarity of the voltage is reversed, the moving direction is reversed. In addition, the flow rate of the liquid can be changed by changing the current or the voltage.
[0003]
[Patent Document 1] JP-A-6-233969
[Problems to be solved by the invention]
However, in the prior art, the displacement of the piezoelectric transducer as a vibration source is generally small, and the displacement of the tube is also small. If the displacement of the tube is small, a sufficient force is not transmitted to the working fluid, so that there is a problem that the amount of working fluid fed is small. In addition, a separate detector for monitoring the flow velocity is required to detect the flow velocity.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid feeder which has a large flow rate of liquid feed, can detect a flow rate without requiring a special sensor, and has high controllability of flow rate and flow rate.
[0005]
[Means for Solving the Problems]
To solve the above problems, the present invention is configured as follows.
The invention according to claim 1 is a liquid supply module including a piezoelectric element, a diaphragm whose one end freely swings on the piezoelectric element, and a voltage supply line to the piezoelectric element.
According to this configuration, the diaphragm can be displaced by applying a voltage to the piezoelectric element.
According to a second aspect of the present invention, there is provided a vibration plate having a bimorph-type piezoelectric plate provided on both surfaces of a metal plate, and a wiring for fixing one end of the vibration plate and supplying a voltage to the metal plate and the piezoelectric plate. It is a liquid feeding module including a provided supporting member.
According to this configuration, the diaphragm can be displaced by applying a voltage to the piezoelectric element.
According to a third aspect of the present invention, a plurality of the liquid supply modules according to the first or second aspect are provided in the flow path of the base, and a power supply for supplying a voltage to the piezoelectric element of the liquid supply module and the voltage are controlled. This is a liquid feeding device constituted by a control device.
According to this configuration, the diaphragm is displaced by applying a voltage to the piezoelectric element, and the liquid can be moved by directly acting on the liquid.
The invention according to claim 4 is a liquid feeder in which the liquid feed modules are arranged so that directions in which they act on each other are reversed.
According to this configuration, it is possible to control the flow direction, the flow rate, and the like by alternately moving the liquid feed module arranged in one direction and the liquid feed module arranged in the opposite direction.
The invention according to claim 5 is a liquid feeder in which the vibration frequency of the diaphragm is changed by a liquid feed module.
According to this configuration, the liquid feeding module can be selectively operated only by changing the driving frequency, so that it is not necessary to individually perform wiring when individually operating. Further, even when a plurality of liquid sending modules are selectively operated, the liquid sending modules can be selectively operated only by changing the frequency without requiring individual wiring.
The invention according to claim 6 is a liquid feeder in which the plurality of liquid feed modules are divided into groups, and voltage supply lines in the groups are wired in series.
According to this configuration, since a plurality of liquid supply modules can be controlled for each group, the number of voltage supply lines can be reduced, and the flow rate and the flow velocity can be controlled with a single voltage.
The invention according to claim 7 is a liquid feeder in which voltage supply lines for all the piezoelectric elements are wired in series.
According to this configuration, since only two voltage supply lines are required, the structure can be simplified.
The invention according to claim 8 uses a liquid supply module to which no voltage is applied among the liquid supply modules, and converts a voltage signal of a piezoelectric element generated by a metal plate displaced by the movement of the liquid into a liquid for flow velocity detection. This is a liquid feeding device as a feeding module.
According to this configuration, it is not necessary to provide a special detector for detecting the flow velocity, so that the structure of the apparatus is simplified.
According to a ninth aspect of the present invention, a liquid supply module including a piezoelectric element, a vibrating plate whose one end freely swings on the piezoelectric element, and a voltage supply line to the piezoelectric element is provided in a flow path inside the base. A driving method of a liquid feeding device that supplies a plurality of piezoelectric elements to generate a vibration by supplying a voltage to the piezoelectric element, transmits the generated vibration to the vibration plate, and applies a displacement enlarged by the vibration plate to the liquid to move the liquid. is there.
According to this configuration, the diaphragm is displaced by applying a voltage to the piezoelectric element, and the liquid can be moved by directly acting on the liquid.
According to a tenth aspect of the present invention, there is provided a vibration plate having a bimorph-type piezoelectric plate provided on both surfaces of a metal plate, and a wiring for fixing one end of the vibration plate and supplying a voltage to the metal plate and the piezoelectric plate. A plurality of liquid feed modules each including a supporting member provided are provided in a flow path inside the base body, a voltage is supplied to the piezoelectric element to generate vibration, the generated vibration is transmitted to the vibration plate, and the vibration is enlarged by the vibration plate. This is a driving method of a liquid feeding device that moves the liquid by applying the displacement to the liquid.
According to this configuration, the diaphragm is displaced by applying a voltage to the piezoelectric element, and the liquid can be moved by directly acting on the liquid. (Write effects different from those in claim 9)
An eleventh aspect of the present invention is a method for driving a liquid feeding device, wherein a voltage supplied to the piezoelectric element is set to a frequency at which the diaphragm resonates.
According to this configuration, the displacement of the diaphragm can be increased, the flow rate can be increased, and the flow velocity can be increased.
The invention according to claim 12 uses the liquid feeding module to which no voltage is applied among the liquid sending modules, detects an electric signal of the piezoelectric element that changes according to the flow rate of the liquid as a flow rate, and This is a method for driving a liquid feeding device for controlling the flow rate of the liquid.
According to this configuration, it is not necessary to provide a special detector for detecting the flow velocity, so that the structure of the apparatus is simplified.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIGS. 1A and 1B are diagrams of a liquid feeder showing a first embodiment of the present invention, wherein FIG. 1A is a perspective view, and FIG. 1B is a partially enlarged sectional view of a liquid feed module. In the figure, 21 is a minute flow path base made of silicon, glass, plastic, or the like, 22 is a minute flow path cover made of silicon, glass, plastic, or the like, and 23 is surrounded by the flow path base 21 and the flow path cover 22. 24, a liquid feed module, 241 a vibration plate, 242 a piezoelectric element, 25 a voltage supply line for the piezoelectric element, and 26 a spacer.
A voltage supply line 25 is provided on the flow path base 21, and portions other than the contact pads (not shown) are covered with a thin film having electrical insulation. The piezoelectric element 242 is arranged thereon so that the piezoelectric element 242 can be in electrical contact with the voltage supply line 25. The piezoelectric element 242 is a multi-layer piezoelectric element in which multiple layers of 50 μm thick piezoelectric ceramics are stacked. By integrating the volume change of each layer, a sufficient volume change can be obtained even at a low driving voltage. An ultraviolet curing adhesive is applied to the surface of the piezoelectric element 242, and the vibration plate 241 is disposed thereon. By irradiating ultraviolet rays from the upper surface, the vibration plate 241 and the piezoelectric element 242 are fixed.
Next, the operation will be described.
When an AC voltage is applied to the piezoelectric element 242, the piezoelectric element 242 expands and contracts in the thickness direction according to the amplitude of the voltage. Since one end of the vibration plate 241 is connected to the piezoelectric element 242, when the piezoelectric element is driven at an appropriate frequency, the other end of the vibration plate 241 is vibrated and deformed into a wave shape. By this operation, the liquid in the minute flow path 23 is sent in one direction.
[0007]
(Second embodiment)
FIG. 2 is a partially enlarged cross-sectional view of a liquid feeding module according to a second embodiment of the present invention.
The liquid feeding module 24 of the present embodiment includes a vibration plate 241 and a support member 242. Other configurations are the same as those of the first embodiment.
The vibration plate 241 includes a metal plate 241a and a piezoelectric plate 241b of a bimorph type piezoelectric element, and has a three-layer structure in which the metal plate 241a is sandwiched between piezoelectric plates 241b formed of barium titanate or lead zirconate titanate. ing. One end of the vibration plate 241 is fixed to the support member 243. The support member 243 is made of an insulator, and includes a relay wiring 243a that supplies a voltage to the metal plate 241a and the piezoelectric plate 241b. One end of the relay wiring 243a is connected to the voltage supply line 25, and the other end is electrically connected to the contact pad and the piezoelectric plate 241b of the bimorph piezoelectric element.
Next, the operation will be described.
When a voltage is applied between the metal plate 241a and the piezoelectric plate 241b, the piezoelectric plate 241b is deformed in one direction as shown by a dotted line in the drawing. When the polarity of the applied voltage is reversed, the piezoelectric plate 241b deforms in the opposite direction. In such a configuration, by applying an AC driving voltage to the liquid feed module 24, the diaphragm 241 bends up and down, and the deformation directly transmits a force to the liquid in the flow path 23 and the liquid moves efficiently.
[0008]
(Third embodiment)
FIG. 3 is a perspective view of a liquid feeder showing a third embodiment of the present invention. A plurality of liquid sending modules 24 are arranged in the + and-directions. When only the liquid feeding module 24 acting in the + direction is operated, the liquid can be moved in the + direction. To stop such a flow instantaneously, a force acting in the opposite direction is required. Therefore, it becomes possible to act as a braking force by operating the liquid feeding device arranged in the negative direction. Further, by simultaneously operating the liquid feeding device arranged in the + direction and the liquid feeding device arranged in the-direction, it is possible to provide the liquid feeding device with a function of stirring in addition to the function of liquid feeding.
[0009]
(Fourth embodiment)
FIG. 4 is a perspective view of a liquid feeder showing a fourth embodiment of the present invention. The resonance frequency changes according to the shape of the diaphragm 241 such as thickness, length, and width. Also, the resonance frequency changes depending on the mechanical properties of the material such as Young's modulus. FIG. 4 shows an example in which diaphragms 241 having different lengths are arranged. All the piezoelectric elements 242 are wired in series, and a liquid feeder having a different resonance frequency is arranged so that the resonance frequency gradually increases from the inlet to the outlet of the liquid. In such a configuration, when the drive frequency is gradually increased, the liquid feeder operates sequentially from the entrance to the exit. Therefore, a traveling wave can be given to the liquid, and the liquid can be sent at a high flow rate per unit time.
The resonance frequency may change the shape such as the width and the thickness and the Young's modulus in addition to the length of the diaphragm 241.
[0010]
(Fifth embodiment)
FIG. 5 is a perspective view of a liquid feeding apparatus according to a fifth embodiment of the present invention. A voltage supply line 25 for individually supplying a voltage to all the piezoelectric elements 242 is provided on the flow path base 21 by using a photolithography technique. Further, except for the electrode pads for contacting the electrodes of each piezoelectric element, the surface of the voltage supply line 25 is covered with an electrically insulating thin film. By applying a voltage to an arbitrary electrode, each liquid feeding device can be individually driven. As described above, by adjusting the number of liquid feeding devices to be driven, the flow rate per unit time can be adjusted with high accuracy. It is also possible to generate a flow locally by operating an arbitrary liquid feeding device. Furthermore, by switching the electrodes to be applied so that the liquid feeding device operates from the inlet to the outlet of the flow path, a traveling wave can be given to the liquid, and the liquid can be sent at a large flow rate per unit time. Become.
[0011]
(Sixth embodiment)
FIG. 6 is a perspective view of a liquid feeding device according to a sixth embodiment of the present invention. Using a photolithography technique, the inside of each group is wired in series with the group of liquid sending modules on the flow path base 21. Further, except for the electrode pads for contacting the electrodes of each piezoelectric element, the surface of the voltage supply line 25 is covered with an electrically insulating thin film. By using such voltage supply lines 25, for example, those operating in the + direction and those operating in the − direction are divided into two groups and wired, thereby reducing the number of voltage supply lines 25. Becomes possible.
[0012]
(Seventh embodiment)
FIG. 7 is a perspective view of a liquid feeder showing a seventh embodiment of the present invention. A voltage supply line 25 is provided on the flow path base 21 using a photolithography technique so that all the piezoelectric elements 242 are wired in series. As compared with the fourth embodiment, although it is disadvantageous in terms of high-precision control, there is an advantage that the number of driving power supplies is only two.
[0013]
(Eighth embodiment)
FIG. 8 is a perspective view of a liquid feeder showing an eighth embodiment of the present invention.
The liquid feeding module 24 is the same as that shown in FIG. 2 of the second embodiment. That is, the diaphragm 241 and the support member 242 are formed, and the diaphragm 241 is formed of the metal plate 241a and the piezoelectric plate 241b. Reference numerals 24A and 24C denote driving liquid sending modules, and 24B denotes a flow rate monitoring liquid sending module.
The driving liquid feed modules 24A and 24C apply an AC drive voltage, and the flow rate monitor liquid feed module detects a voltage V between the metal plate 241a and the piezoelectric plate 241b. According to the arrangement shown in the figure, by applying a drive voltage, the bimorph type of the liquid feed modules 24A and 24C is deformed up and down, and a flow occurs in the direction of the arrow shown in the figure. The force applied to the liquid feed module 24B changes according to the flow speed, and the liquid feed module undergoes deformation according to the force, and the deformation generates a voltage between the metal plate and the piezoelectric plate.
FIG. 9 is a graph showing the output characteristics of the flow rate sensor of this embodiment. It can be seen that the voltage increases as the flow velocity increases.
[0014]
【The invention's effect】
As described above, according to the liquid feeder of the present invention, a liquid feeder having a higher controllability with respect to the flow direction, the flow rate, and the flow velocity, and a larger liquid feed amount than the conventional liquid feeder. There are effects that can be provided.
[Brief description of the drawings]
FIG. 1 is a view of a liquid feeder showing a first embodiment of the present invention, (a) is a perspective view, and (b) is a partially enlarged cross-sectional view of a liquid feed module. FIG. 2 is a second embodiment of the present invention. FIG. 3 is a partially enlarged cross-sectional view of a liquid feeding module showing an example. FIG. 3 is a perspective view of a liquid feeding device showing a third embodiment of the present invention. FIG. 4 is a perspective view of a liquid feeding device showing a fourth embodiment of the present invention. FIG. 5 is a perspective view of a liquid feeder showing a fifth embodiment of the present invention. FIG. 6 is a perspective view of a liquid feeder showing a sixth embodiment of the present invention. FIG. 7 shows a seventh embodiment of the present invention. FIG. 8 is a perspective view of a liquid feeder according to an eighth embodiment of the present invention. FIG. 9 is a graph showing output characteristics of a flow rate sensor according to an eighth embodiment of the present invention. Sectional view showing the liquid feeder of [Description of reference numerals]
T Traveling wave generator 1 Tube 3 Ultrasonic generator 9 Lower electrode 13 Upper electrode 7, 11 Film 21 Flow path base 22 Flow path cover 23 Flow paths 24, 24A, 24C Liquid feed module (for driving)
24B liquid feed module (for flow velocity monitor)
241 Vibration plate 241a Metal plate 241b Piezoelectric plate 242 Piezoelectric element 243 Support member 243a Relay wiring 25 Voltage supply line 26 Spacer

Claims (12)

A liquid supply module comprising: a piezoelectric element; a vibration plate fixed to the piezoelectric element; one end of which freely swings; and a voltage supply line to the piezoelectric element. A vibration plate provided with a bimorph-type piezoelectric plate on both surfaces of a metal plate, and a supporting member having one end fixed to the vibration plate and provided with wiring for supplying a voltage to the metal plate and the piezoelectric plate. Characteristic liquid supply module. A plurality of liquid supply modules according to claim 1 or 2 are provided in a flow path of a base, and are configured by a power supply for supplying a voltage to a piezoelectric element of the liquid supply module and a control device for controlling the voltage. Liquid feeding device. 4. The liquid feeding device according to claim 3, wherein the liquid feeding modules are arranged so that the directions acting on each other are reversed. The liquid feeding device according to claim 3, wherein the vibration frequency of the vibration plate is changed by a liquid feeding module. The liquid feeding apparatus according to any one of claims 3 to 5, wherein the plurality of liquid feeding modules are divided into groups, and voltage supply lines in the groups are wired in series. The liquid feeder according to any one of claims 3 to 5, wherein the voltage supply lines of all the piezoelectric elements are wired in series. A liquid supply module to which a voltage is not applied is used, and a voltage signal of a piezoelectric element generated by a metal plate displaced by the movement of the liquid is used as a liquid supply module for detecting a flow velocity. The liquid feeder according to any one of claims 3 to 7. A plurality of liquid feed modules each including a piezoelectric element, a vibration plate whose one end freely swings on the piezoelectric element, and a voltage supply line to the piezoelectric element are provided in a flow path inside the base, and a voltage is applied to the piezoelectric element. A driving method for a liquid feeder, comprising: supplying vibration to generate vibration, transmitting the generated vibration to the vibration plate, and applying displacement expanded by the vibration plate to the liquid to move the liquid. A liquid feeder comprising: a vibrating plate having a bimorph-type piezoelectric plate provided on both surfaces of a metal plate; and a supporting member having one end fixed to the vibrating plate and having a wiring for supplying a voltage to the metal plate and the piezoelectric plate. A plurality of modules are provided in a flow path inside the base body, a voltage is supplied to the piezoelectric element to generate vibration, the generated vibration is transmitted to the vibration plate, and the displacement enlarged by the vibration plate is added to the liquid to apply the liquid. A method for driving a liquid feeding device, comprising: moving the liquid feeding device. 11. The method according to claim 9, wherein the voltage supplied to the piezoelectric element is a frequency at which the diaphragm resonates. Using a liquid supply module to which no voltage is applied among the liquid supply modules, detecting an electric signal of the piezoelectric element that changes according to the flow velocity of the liquid as a flow velocity, and controlling a flow rate of the liquid. The method for driving a liquid feeding device according to claim 9, wherein

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