JP2008101969A - Liquid conveyance method and liquid conveyer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain a liquid from being spread on a surface of a substrate, in a method of conveying the liquid by a surface acoustic wave and a conveyer for conveying the liquid by the surface acoustic wave. <P>SOLUTION: This method/conveyer includes a step for laying a solid piece on the substrate, a step for dropping the liquid on the substrate, a step for exciting the surface acoustic wave on the substrate, and a step for bringing the liquid dropped on the substrate into contact with the solid piece laid on the substrate to be migrated between the solid piece and the substrate, and the liquid migrated between the solid piece and the substrate is conveyed by the surface acoustic wave together with the solid piece. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for transporting liquid by surface acoustic waves and an apparatus for transporting liquid by surface acoustic waves.

  2. Description of the Related Art Liquid transport devices that transport liquid by surface acoustic waves excited on a substrate are widely used. The liquid on the substrate is transported by receiving a force in the direction in which the excited surface acoustic wave propagates. Such a liquid transport apparatus is used for carrying a liquid into an analysis apparatus on a substrate for analyzing properties of a substance contained in the liquid.

JP-T-2004-534633 Special table 2003-535349 gazette

  In the conventional liquid transfer device, there is a problem that when the liquid is transferred onto the substrate, the liquid spreads on the surface of the substrate, and the frictional force between the liquid and the substrate increases. For this reason, it is necessary to increase the intensity of the surface acoustic wave for transporting the liquid. Further, since the liquid spreads on the surface of the substrate, there is a problem that the evaporation of the liquid is promoted. The present invention has been made for such a problem. That is, an object of the present invention is to suppress the spread of liquid on the surface of a substrate in a method for transporting liquid by surface acoustic waves and an apparatus for transporting liquid by surface acoustic waves.

  The present invention includes a step of placing a solid piece on a substrate, a step of dropping a liquid on the substrate, a step of exciting a surface acoustic wave on the substrate, and the liquid dropped on the substrate. Contacting the solid piece placed on the substrate and allowing the liquid to enter between the solid piece and the substrate, the liquid entering between the solid piece and the substrate Is transported together with the solid piece by the surface acoustic wave.

  The present invention also provides a substrate on which surface acoustic waves propagate, an excitation source for exciting surface acoustic waves on the substrate, a set unit for placing a solid piece on the substrate, and a liquid dropped on the substrate. And a dripping unit.

  Further, in the liquid transport device according to the present invention, the set unit has a hole through which gas flows, and holds the solid piece at a position where the hole is provided by sucking the solid piece. It is characterized in that the held solid piece is released by discharging gas from the hole.

  In the liquid transport device according to the present invention, it is preferable that the solid piece is a plate-like solid member, and one of the two opposing surfaces is more hydrophobic than the other surface. is there.

  In the liquid transfer device according to the present invention, it is preferable that the solid piece is a spherical solid member.

  Further, as a plate-like member applied to the method or apparatus according to the present invention, the plate-like member is disposed at a position in contact with the liquid dropped on the substrate on which the surface acoustic wave propagates, and enters the liquid between the substrate. It is preferable to apply a plate-like member that is transported by the surface acoustic wave together with the liquid that has entered, and in which one of the two faces facing each other is more hydrophobic than the other face.

  ADVANTAGE OF THE INVENTION According to this invention, in the method of conveying a liquid with a surface acoustic wave, and the apparatus which conveys a liquid with a surface acoustic wave, it can suppress that a liquid spreads on the surface of a board | substrate.

  FIG. 1 is a perspective view of an analysis system according to the first embodiment of the present invention. The analysis system includes a substrate 10, an analysis device 12, guide walls 14 a and 14 b, an electrode pair 16, a liquid dropping device 18, a chip set device 20, a chip Tp, and a chip recovery device 22. FIG. 2 is a view of the liquid dropping device 18, the chip set device 20, and the chip collecting device 22 removed from the analysis system, as viewed from above the substrate 10. However, the positions where the liquid dropping device 18, the chip set device 20 and the chip collecting device 22 are attached are indicated by points P1, P2 and P3, respectively.

  The substrate 10 is formed of a piezoelectric material that can generate a surface acoustic wave by a piezoelectric phenomenon, such as quartz, lithium niobate, or lithium tantalate.

  The analysis device 12 is provided on the substrate 10. The analysis device 12 is covered with a housing 12A having an opening 12B. Here, the housing 12A has a rectangular parallelepiped shape, and has a rectangular opening 12B on one surface thereof. The analysis device 12 analyzes the amount, property, etc. of the substance contained in the liquid carried in from the opening 12B. As the analysis device 12, for example, a device capable of analyzing the property of a substance contained in a liquid by measuring the resonance frequency with respect to the electromagnetic wave, the propagation property of the electromagnetic wave, the light transmission and reflection, the electric resistance, or the like is applied. .

  The guide walls 14a and 14b are arranged in parallel on the substrate 10 with the opening 12B of the analyzer 12 interposed therebetween. The distance between the guide wall 14a and the guide wall 14b is slightly larger than the width of the opening 12B. One end of each of the guide walls 14a and 14b is joined to the surface of the housing 12A where the opening 12B is provided. The guide walls 14a and 14b are preferably formed of a resin that can be molded and processed in a viscous liquid state, such as an epoxy resin. Moreover, although the shape of the cross section perpendicular | vertical to the extending | stretching direction of these walls is arbitrary, it shall be a rectangle here.

  The electrode pair 16 includes interdigital electrodes E1 and E2 in which a plurality of linear conductors e are connected to one linear main conductor r in an interdigital manner. The interdigital electrodes E1 and E2 are arranged such that the linear conductor e belonging to the interdigital electrode E1 and the linear conductor e belonging to the interdigital electrode E2 are alternately arranged. The distance between the two linear conductors e adjacent to each other is preferably about half the wavelength of the surface acoustic wave to be excited.

  The electrode pair 16 is disposed in the vicinity of the end of the guide wall 14a that is not joined to the analysis device 12 and the end of the guide wall 14b that is not joined to the analysis device 12. The electrode pair 16 is preferably disposed between a straight line A that contacts the surface of the guide wall 14a facing the guide wall 14b and a straight line B of the guide wall 14b that contacts the surface facing the guide wall 14a. The electrode pair 16 is arranged such that the extending direction of the linear conductor e is substantially perpendicular to the extending direction of the guide wall 14a and the extending direction of the guide wall 14b.

  Various shapes can be applied as the shape of the electrode pair 16 in addition to those shown in FIGS. 1 and 2. For example, an electrode having an angle between the main conductor r and the linear conductor e different from 90 ° and a linear conductor e whose width changes from one end to the other end are provided. It is possible to apply an electrode or the like in which the linear conductors e are arranged so that the interval between the linear conductors e adjacent to each other is not uniform. That is, the electrode can have an arbitrary shape based on the frequency range of the surface acoustic wave to be excited, the direction of propagation, and the like.

  An operation for exciting a surface acoustic wave from the electrode pair 16 will be described. When an AC voltage having a predetermined frequency is applied between the interdigital electrodes E1 and E2 included in the electrode pair 16, the surface acoustic wave SAW is excited in the direction away from the electrode pair 16 toward the analysis device 12 due to the piezoelectric effect. . The surface acoustic wave SAW propagates through a region sandwiched between the guide wall 14a and the guide wall 14b and propagates through a position where the analysis device 12 is provided.

  The relationship between the direction in which the electrode pair is arranged and the direction in which the excited surface acoustic wave propagates varies depending on the shape of the electrode, the physical properties of the substrate, and the like. Therefore, the direction in which the electrode pair 16 is arranged is determined so that the surface acoustic wave SAW propagates in a predetermined direction. The present embodiment shows an example of the arrangement direction of the electrode pair 16 determined as described above.

  The liquid dropping device 18 includes a support 18A, an arm 18B, and a dropping unit 18F. The support 18A and the arm 18B are formed in a rod shape from a rigid material such as metal or plastic.

  The support 18 </ b> A is attached to the substrate 10 such that the extending direction thereof is perpendicular to the surface of the substrate 10. The position where the column 18A is attached is the position of a point P1 that is a predetermined distance away from the vicinity of the end of the guide wall 14b that is not joined to the analysis device 12 in a direction substantially perpendicular to the extending direction of the guide wall 14b. .

  The arm 18B has substantially the same length as the perpendicular line drawn from the point P1 to the straight line F that is the center line between the guide wall 14a and the guide wall 14b. One end of the arm 18B is joined to the end of the support 18A that is not joined to the substrate 10. A drip portion 18F is attached to the end of the arm 18B on the side not joined to the column 18A. The arm 18B is joined to the column 18A in a direction in which the dropping portion 18F is fixed above the vicinity of the conveyance start region St so that the extending direction is parallel to the surface of the substrate 10. Here, the conveyance start area St is the guide wall 14a and the guide wall 14b in the vicinity of the end of the guide wall 14a on the side not joined to the analysis device 12 and the end of the guide wall 14b on the side not joined to the analysis device 12. Is an area between which the liquid is transferred.

  The dropping portion 18F applied in the present embodiment is formed in the shape of an elongated tube, and a dropping port 18H for dropping a liquid is provided at one end of the tube. The dropping unit 18F is attached to the arm 18B so that the dropping port 18H faces the substrate 10 and the dropping port 18H is separated from the surface of the substrate 10 by a predetermined distance. The dropping unit 18F can be configured by a pipette or the like. The liquid dropping device 18 drops liquid on the substrate 10 under the control of the dropping unit 18F.

  The chip set device 20 includes a support 20A, an arm 20B, and a set unit 20F. The support 20A and the arm 20B are formed in a rod shape by a rigid material such as metal or plastic.

  The support 20 </ b> A is attached to the substrate 10 so that the extending direction thereof is perpendicular to the surface of the substrate 10. The position where the column 20A is attached is the position of a point P2 that is separated from the transfer start region St by a predetermined distance in a direction substantially perpendicular to the extending direction of the guide wall 14b.

  The arm 20B has a length substantially the same as the length of the perpendicular drawn from the point P2 to the straight line F. One end of the arm 20B is joined to the end of the support 20A that is not joined to the substrate 10. A set portion 20F is attached to the end of the arm 20B on the side not joined to the support 20A. The arm 20B is joined to the support column 20A in the direction in which the set portion 20F is fixed above the transfer start region St so that the extending direction is parallel to the surface of the substrate 10.

  The set portion 20F applied in the present embodiment is formed in the shape of an elongated tube, and at one end of the tube, a chip Tp, which is a small piece of a solid substance used for transporting a liquid, is adsorbed or detached by gas pressure. An attachment / detachment hole 20H is provided. The set portion 20F is attached to the arm 20B so that the attachment / detachment hole 20H faces the substrate 10 and the attachment / detachment hole 20H is separated from the surface of the substrate 10 by a predetermined distance. The set unit 20F can be configured by a vacuum suction device that sucks or removes the chip Tp by suction or discharge of gas, tweezers that opens and closes by control from the outside, and the like.

  The chip set device 20 holds the chip Tp or releases the chip Tp under the control of the setting unit 20F. When a vacuum suction device is applied as the set unit 20F, the chip Tp is held by setting the set unit 20F to a suction state, and the chip Tp is released by setting the set unit 20F to a discharge state.

  As shown in FIGS. 3C and 3D showing the cross section along the straight line F in FIG. 2, the chip Tp allows the analysis liquid Lq containing a substance to be analyzed in the analysis device 12 between the substrate 10. It is a small piece of solid material that enters and draws the analysis liquid Lq. The interaction between the chip Tp and the analysis liquid Lq will be described later. The tip Tp is preferably formed in a disc shape whose diameter is larger than the width of the opening 12B and smaller than the width of the region sandwiched between the guide wall 14a and the guide wall 14b. The chip Tp may be formed in an arbitrary polygonal plate shape in addition to the circular plate. The chip Tp is preferably formed of a rigid material such as silicon, glass, or plastic.

  The tip Tp is processed so that the surface on the side where the analysis liquid Lq does not contact is more hydrophobic than the surface on which the analysis liquid Lq contacts. Here, the term “hydrophobic” refers to the property that when a plate-like member is installed horizontally and a liquid is dropped on it, the shape of the liquid becomes nearly spherical. When the liquid spreads on the surface of the plate, it can be said that the hydrophobic property is weak and the hydrophilic property is strong. The strength of the hydrophobic nature of the surface of the chip Tp can be adjusted by plasma treatment applied to the surface, treatment with a chemical applied to the surface, or the like. By processing the surface on the side that does not come into contact with the analysis liquid Lq so that the hydrophobic property is stronger than the surface on which the analysis liquid Lq comes into contact, it is possible to prevent the tip Tp from being immersed in the analysis liquid Lq.

  The chip collection device 22 includes a support 22A, an arm 22B, and a collection unit 22F. The support 22A and the arm 22B are formed in a rod shape from a rigid material such as metal or plastic.

  The support column 22 </ b> A is attached to the substrate 10 so that its extending direction is perpendicular to the surface of the substrate 10. The position where the column 22A is attached is a position of a point P3 that is separated from the collection area Ed by a predetermined distance in a direction substantially perpendicular to the extending direction of the guide wall 14b. Here, the collection area Ed is an area sandwiched between the guide wall 14a and the guide wall 14b in the vicinity of the opening 12B of the analyzer 12.

  The arm 22B has substantially the same length as the perpendicular drawn from the point P3 to the straight line F. One end of the arm 22B is joined to the end of the support 22A that is not joined to the substrate 10. A recovery unit 22F is attached to the end of the arm 22B that is not joined to the support 22A. The arm 22B is joined to the support 22A in a direction in which the recovery part 22F is fixed above the recovery region Ed so that the extending direction thereof is parallel to the surface of the substrate 10.

  The collection unit 22F applied in the present embodiment has the same configuration and function as the set unit 20F. The collection portion 22F is attached to the arm 22B so that the attachment / detachment hole 22H faces the substrate 10 and the attachment / detachment hole 22H is separated from the surface of the substrate 10 by a predetermined distance.

  The chip collecting device 22 sucks and holds the chip Tp under the control of the collecting unit 22F. When a vacuum suction device is applied as the collection unit 22F, the chip Tp is collected and held by bringing the collection unit 22F into a suction state.

  A process of transporting the analysis liquid Lq to the analysis device 12 will be described with reference to FIGS. 3A to 3E show the analysis system with a cross section along a straight line F. FIG. The same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted below. First, as shown in FIG. 3A, the chip set device 20 is in a state of holding the chip Tp. Further, a predetermined alternating voltage is applied to the electrode pair 16 so that the surface acoustic wave SAW is excited. In this state, the chip set device 20 releases the chip Tp on the transfer start area St as shown in FIG. The liquid dropping unit 18 drops the analysis liquid Lq onto a region on the substrate 10 between the chip Tp placed on the substrate 10 and the electrode pair 16.

  The dropped analysis liquid Lq moves by receiving a force traveling in the direction in which the surface acoustic wave SAW propagates due to the radiation pressure of the surface acoustic wave SAW. The analysis liquid Lq that has moved to the position where the chip Tp is placed and has come into contact with the chip Tp enters a gap formed between the surface of the substrate 10 and the chip Tp by surface tension. This is shown in FIG. 3 (c). In general, liquids have the property of entering a narrower region surrounded by the solid by surface tension and the property of attracting each other to reduce the surface area. Therefore, the analysis liquid Lq in contact with the chip Tp enters a gap formed between the chip Tp and the surface of the substrate 10 to form a coherent droplet.

  After the analysis liquid Lq enters between the chip Tp and the surface of the substrate 10, the chip Tp is in a state where the contact with the analysis liquid Lq is maintained by the air pressure received by the surface not in contact with the analysis liquid Lq. As a result, the tip Tp becomes as if it is attracted to the analysis liquid Lq, and when the droplet formed by the analysis liquid Lq moves on the surface of the substrate 10, the tip Tp forms the analysis liquid Lq. Move with the droplet.

  Here, the process of releasing the chip Tp and then dropping the analysis liquid Lq has been described, but the process of dropping the analysis liquid Lq first and releasing the chip Tp on the analysis liquid Lq may be executed. . In this case, the timing at which the AC voltage is applied to the electrode pair 16 may be before dropping the analysis liquid Lq or before dropping the chip Tp after dropping the analysis liquid Lq.

  The analysis liquid Lq receives a force that travels in the direction in which the surface acoustic wave SAW propagates due to the radiation pressure of the surface acoustic wave SAW while forming a droplet between the chip Tp and the surface of the substrate 10, and moves together with the chip Tp. . And it is conveyed by the collection | recovery area | region Ed, being guide | induced to the guide walls 14a and 14b. FIG. 3D shows how the analysis liquid Lq and the tip Tp move in the same direction as the direction in which the surface acoustic wave SAW propagates.

  When the analysis liquid Lq and the chip Tp are transported to the recovery area Ed, the chip recovery device 22 recovers the chip Tp as shown in FIG. The analysis liquid Lq transferred to the collection area Ed is transferred from the opening 12B to the inside of the analysis device 12. The analysis device 12 analyzes the amount, property, etc. of the substance contained in the analysis liquid Lq carried from the opening 12B.

  According to such a configuration, the analysis liquid Lq enters between the chip Tp and the surface of the substrate 10 and is transported as a droplet having a unity. As a result, the analysis liquid Lq can be prevented from spreading on the surface of the substrate 10, and the frictional force between the analysis liquid Lq and the substrate 10 can be reduced. Therefore, the analysis liquid Lq can be transported by a weak surface acoustic wave, and the apparatus (not shown) for applying an AC voltage to the electrode pair 16 can be downsized. In addition, since the analysis liquid Lq can be prevented from spreading on the surface of the substrate 10, the analysis liquid Lq can be prevented from evaporating during the transport.

  In the present embodiment, the chip set device 20 and the chip collection device 22 are provided separately. Since these have a common function of attaching and detaching the chip Tp, it is possible to configure a chip set collection device in which these are shared. In this case, a suspension rail is provided that reciprocates in the extending direction of the region above the region sandwiched between the guide wall 14a and the guide wall 14b while suspending a vacuum suction device or the like for attaching and detaching the chip Tp. What is necessary is just to make it the structure which suspended the vacuum suction device etc. in the.

  Further, the chip Tp may be manually arranged or collected using tweezers or the like without providing an instrument for attaching / detaching the chip Tp. Similarly, instead of the liquid dropping device 18, the liquid may be dropped manually using a pipette or the like.

It is a figure which shows the perspective view of the analysis system which concerns on embodiment of this invention. It is the figure which looked at the analysis system which removed the liquid dropping device, the chip set device, and the chip collection device from the upper side of the substrate. It is a figure which shows the process which conveys a liquid.

Explanation of symbols

  10 substrate, 12 analyzer, 12A housing, 12B opening, 14a, 14b guide wall, 16 electrode pair 18 liquid dropper, 18A, 20A, 22A strut, 18B, 20B, 22B arm, 18F drop unit, 18H drop port, 20F set part, 20H, 22H detachable hole, 22F collection part, 20 chip set unit, 22 chip collection unit, r core conductor, e linear conductor, Tp chip, Lq analysis liquid SAW surface acoustic wave.

Claims (4)

Placing a solid piece on the substrate;
Dropping a liquid on the substrate;
Exciting a surface acoustic wave on the substrate;
Bringing the liquid dropped on the substrate into contact with a solid piece placed on the substrate and allowing the liquid to enter between the solid piece and the substrate;
Including
A liquid transport method comprising transporting the liquid that has entered between the solid piece and the substrate together with the solid piece by the surface acoustic wave. A substrate on which surface acoustic waves propagate;
An excitation source for exciting a surface acoustic wave on the substrate;
A set part for placing a solid piece on the substrate;
A dropping unit for dropping a liquid on the substrate;
A liquid transport apparatus comprising: The liquid transport device according to claim 2,
The set part is
Has a hole through which gas flows,
A liquid transporting apparatus, wherein the solid piece is held at a position where the hole is provided by sucking the solid piece, and the held solid piece is released by discharging gas from the hole. It is a liquid conveyance apparatus of Claim 2 or Claim 3, Comprising:
The solid piece is
A plate-like solid member,
One of two opposing surfaces has a higher hydrophobicity than the other surface.

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