WO2017078059A1

WO2017078059A1 - Electrowetting device, method for manufacturing same, and droplet injection method

Info

Publication number: WO2017078059A1
Application number: PCT/JP2016/082553
Authority: WO
Inventors: 知子寺西; 昊李
Original assignee: シャープマイクロフルイディックソリューションズリミテッド
Priority date: 2015-11-06
Filing date: 2016-11-02
Publication date: 2017-05-11

Abstract

An electrowetting device (1) is provided with a lower substrate (10) that has an electrode (13) and an upper substrate (20) that has an electrode (22). The upper substrate (20) has through-holes (25), and the electrode (13) is provided in an area including the area directly below the through-holes (25). A hydrophobic layer (23) is provided on the upper surface of the upper substrate (20), a hydrophobic layer (15) is provided on the upper surface of the lower substrate (10), and a hydrophilic layer (24) is provided inside the through-holes (25).

Description

Electrowetting device, manufacturing method thereof, and droplet injection method

The present invention relates to an electrowetting device, a manufacturing method thereof, and a droplet injection method.

In the field of microfluidics and the like, operation and accurate control of small-scale fluids such as sub-microliters are required. Therefore, attention has been paid to electrowetting for manipulating droplets by applying an electric field.

Electrowetting is the application of an electric field to a droplet placed on a dielectric layer that has been subjected to a hydrophobic treatment (water repellent treatment) provided on an electrode. This is a phenomenon in which the surface energy of the dielectric layer is changed by the electrostatic energy of the capacitor to be formed, so that the solid-liquid interface energy is changed and the contact angle of the droplet with respect to the dielectric film surface is changed.

In recent years, development of electrowetting devices (also referred to as microfluidic devices or droplet devices) using such electrowetting has been underway (see, for example, Patent Documents 1 to 3).

In many cases, in order to prevent loss due to evaporation or the like, the droplet is enclosed in a micro flow channel (micro flow channel) surrounded by the lower substrate and the upper substrate in the electrowetting apparatus.

The droplet (fluid) enclosed in the channel is torn into a predetermined amount of finer droplets as required by applying an appropriate voltage.

Japanese Patent Publication “Japanese Unexamined Patent Publication No. 2013-128920 (released on July 4, 2013)” Japanese Patent Publication “Japanese Patent Laid-Open No. 2012-17697 (published on September 13, 2012)” US Patent Application Publication No. 201200282608 (published on November 11, 2010) US Pat. No. 5,096,669 (registered March 17, 1992)

The liquid droplets sealed in the flow path are injected into the flow path using a fluid injection mechanism for forcibly feeding a fluid (droplet) into the flow path and a storage mechanism for a target liquid amount.

The reason for this will be described below with reference to FIGS. 18A to 18C and FIGS. 19A and 19B. 18 (a) to 18 (c) are cross-sectional views showing the problems of the conventional electrowetting device. FIG. 19A is a perspective view showing a problem of the electrowetting device shown in FIG. 18A, and FIG. 19B is an electrowetting shown in FIG. It is a figure which shows the photograph of the principal part of a ting apparatus (namely, electrowetting apparatus shown to (a) of FIG. 18).

In the electrowetting device, as described above, by applying a voltage to a droplet placed on a dielectric layer that has been subjected to hydrophobic treatment provided on an electrode, the droplet is deformed, for example, Displace (move).

Therefore, as shown in FIGS. 18A to 18C, the droplet 40 (fluid) in the flow path 30 surrounded by the lower substrate 10 and the upper substrate 20 in the electrowetting apparatus comes into contact.

Hydrophobic layers

15 and 23 are formed on the interface by applying a hydrophobic treatment. Although not shown, the droplet 40 injected into the flow path 30 is torn into a predetermined amount of finer droplets as necessary by applying an appropriate voltage.

In the electrowetting device, the lower substrate 10 and the upper substrate 20 are subjected to hydrophobic treatment in order to perform hydrophobic treatment in the flow path 30.

The liquid droplet 40 passes through the gap 30 between the lower substrate 10 and the upper substrate 20 at the edge of the electrowetting device, or from the through-hole 25 provided as a liquid droplet injection port in the upper substrate 20 into the flow path 30. Injected into.

However, a sealing material 31 is provided in the gap between the lower substrate 10 and the upper substrate 20 at the edge of the electrowetting device. For this reason, the through hole 25 is preferably formed in the upper substrate 20.

When the through hole 25 is formed in the upper substrate 20, generally, after the through hole 25 is formed, the entire upper substrate 20 is formed by, for example, a dip coating method. Therefore, in this case, the hydrophobic layer 23 is also formed in the through hole 25 as shown in FIGS.

For this reason, the conventional electrowetting device shown in FIGS. 18A and 18B has not only very little familiarity between the

hydrophobic layers

15 and 23 and the droplets 40 in the flow path 30. In the first place, it is difficult for the droplet 40 to enter the flow path 30. For this reason, simply dropping the droplet 40 into the through-hole 25, as shown in FIGS. 18 (a) and (b) and FIGS. 19 (a) and (b), in the electrowetting device (that is, The droplets 40 do not naturally flow into the cells made up of the lower substrate 10 and the upper substrate 20 bonded together.

As shown in FIGS. 18A and 18B and FIGS. 19A and 19B, the contact surface with the droplet 40 in the path from the through hole 25 in the upper substrate 20 to the flow path 30 is shown. When all of the surfaces are hydrophobic, the capillary phenomenon occurs regardless of whether or not the hydrophobic layer 23 is formed on the upper surface of the upper substrate 20 (that is, the surface of the upper substrate 20 opposite to the surface facing the lower substrate 10). Does not occur well, and the droplet 40 is ejected from the through hole 25 due to the surface tension.

For this reason, the droplet 40 dropped on the through hole 25 is formed on the dielectric layer 14 provided on the electrode 13 and covered with the hydrophobic layer 15 in the lower substrate 10 (that is, the lower substrate 10 in the flow path 30). A special fluid injection mechanism is required to perform the electrowetting operation.

Further, according to the study by the inventors of the present application, as shown in FIG. 18C, the

hydrophobic layers

15 and 23 are formed only at the interface in contact with the liquid droplet 40 in the flow path 30, and the upper substrate 20 When the hydrophobic layer 23 is not formed on the upper surface, the droplet 40 dropped on the through-hole 25 has a force that always spreads and spreads on the upper surface of the upper substrate 20. Therefore, in this case, even if the droplet 40 dropped on the through-hole 25 reaches the surface of the lower substrate 10 in the flow channel 30, the droplet 40 is drawn into the flow channel 30 by the electrowetting operation. It is difficult to go.

Therefore, even if the

hydrophobic layers

15 and 23 are formed only on the opposing surfaces of the lower substrate 10 and the upper substrate 20 by using a spin coat method or the like after the through hole 25 is formed in the upper substrate 20, the cell The droplet 40 does not naturally flow into the inside.

Therefore, in any case, a special fluid injection mechanism is required to draw the droplet 40 into the cell and perform the electrowetting operation.

For example, Patent Document 1 discloses a metering fluid loading system formed integrally with an electrowetting device as a fluid injection mechanism.

The metering fluid loading system includes a reservoir having an inflow channel, and moves or expands the fluid or gas in the reservoir so that a part of the fluid in the inflow channel of the reservoir is transferred to the electrowetting device. In an extrusion and electrowetting device, an appropriate voltage is applied to the electrodes to cause individually metered volumes of droplets (fluids) to flow out. This forcibly injects droplets (fluid) into the gap between the upper substrate and the lower substrate in the electrowetting device.

As described above, in order to send a droplet (fluid) into the gap (microchannel) between the upper substrate and the lower substrate in the electrowetting device, a special fluid injection mechanism is required, and the configuration is complicated. Turn into.

Further, Patent Document 2 includes an upper substrate provided with an opening and a lower substrate, and an electrowetting device that sends fluid from the opening to a flow path formed between the upper substrate and the lower substrate. A gating device is disclosed. However, Patent Document 2 does not disclose how the fluid is fed into the electrowetting device.

Similarly, Patent Document 3 discloses an electrowetting device in which droplets are sealed in a gap between an upper substrate and a lower substrate, but a method for injecting droplets into the electrowetting device is also disclosed. Not.

In addition, as a fluid inflow mechanism, for example, Patent Document 4 discloses a system used for an apparatus for analyzing a droplet sample.

In Patent Document 4, an opening provided at one end of a second conduit having an opening for receiving the fluid at one end and a capillary opening at the other end is used as a fluid used for measurement. In contact and drawn by capillary action into the second conduit, the fluid fills the second conduit, and then the opening is sealed. Thereafter, air is pushed out from the cavity functioning as an air bag by the fourth conduit toward the second conduit. As a result, the fluid in the second conduit is extruded from the second conduit to the third conduit connected to the capillary port of the second conduit, and the extruded fluid reaches the sensor. Measurement is performed.

However, in addition to the complexity of the system, there is no disclosure of how individual droplets of fluid are injected into the system.

The present invention has been made in view of the above problems, and an object thereof is an electrowetting device capable of injecting droplets into an electrowetting device without requiring a complicated fluid injection mechanism, and its It is an object to provide a manufacturing method and a droplet injection method.

In order to solve the above problems, an electrowetting device according to one embodiment of the present invention includes a lower substrate having a first electrode and an upper substrate having a second electrode, which are bonded to each other with a gap. The upper substrate has an injection port for injecting a droplet into the gap, and the first electrode is provided in a region including a region immediately below the injection port, and on the upper surface of the upper substrate, A hydrophobic layer is provided in each of the region where the droplet contacts and the region where the droplet contacts in the lower substrate, and a hydrophilic layer having a higher surface tension than the hydrophobic layer is provided in the inlet. ing.

In order to solve the above problems, a droplet injection method according to an aspect of the present invention is a method of injecting a droplet into an electrowetting device according to an aspect of the present invention, wherein the droplet is injected into the injection port. A step of dropping a droplet, and in a state where the droplet dropped to the injection port is in contact with the lower substrate, applying a voltage to the first electrode and the second electrode to move the droplet, The droplet is drawn into the gap.

In order to solve the above-described problems, a method for manufacturing an electrowetting device according to one aspect of the present invention includes a lower substrate forming step of forming a lower substrate on which a first electrode is formed, and a second electrode. An upper substrate forming step of forming an upper substrate; and a bonding step of bonding the upper substrate and the lower substrate with a gap between each other, wherein the upper substrate forming step drops droplets into the gap. An injection hole forming step for forming an injection hole to be injected; an upper substrate hydrophobic layer forming step for forming a hydrophobic layer in a region where the droplet contacts on the upper surface of the upper substrate; and Forming a hydrophilic layer having a high surface tension, wherein the lower substrate forming step includes forming the first electrode in a region including a region immediately below the inlet, and the liquid The area where the drop comes into contact To include a lower substrate hydrophobic layer forming step of forming a hydrophobic layer.

According to one aspect of the present invention, an electrowetting device that can inject droplets into an electrowetting device without requiring a complicated fluid injection mechanism, a manufacturing method thereof, and a droplet injection method are provided. can do.

(A) is a disassembled perspective view which shows schematic structure of the principal part of the electrowetting apparatus concerning Embodiment 1 of this invention, (b) is the fluid of the electrowetting apparatus concerning Embodiment 1 of this invention. It is sectional drawing which expands and shows the structure of the injection hole vicinity. It is sectional drawing which shows schematic structure of a pair of array element in the electrowetting apparatus concerning Embodiment 1 of this invention. It is a top view which shows an example of schematic structure of the thin film electronic circuit in the electrowetting apparatus concerning Embodiment 1 of this invention. (A)-(d) is a figure which shows a part of manufacturing process of the upper board | substrate in the electrowetting apparatus concerning Embodiment 1 of this invention in order of a process. (A)-(d) is a figure which shows the surface treatment process of the upper board | substrate in the electrowetting apparatus concerning Embodiment 1 of this invention in order of a process. (A)-(e) is sectional drawing which shows in order a mode that a droplet is drawn in in the electrowetting apparatus concerning Embodiment 1 of this invention. (A)-(c) is a perspective view which shows sequentially a mode that a droplet is drawn in in the electrowetting apparatus concerning Embodiment 1 of this invention. (A) is a perspective view which shows a mode that a droplet is drawn in in the electrowetting apparatus concerning Embodiment 1 of this invention, (b) is a principal part of the electrowetting apparatus shown to (a). It is a figure which shows a photograph. It is sectional drawing which expands and shows the structure of the fluid injection hole vicinity of the electrowetting apparatus concerning Embodiment 2 of this invention. (A)-(c) is sectional drawing which shows the process of forming a resist pattern in the area | region around the formation scheduled area | region of the through-hole of a mother substrate. (A)-(e) is sectional drawing which shows sequentially a mode that a droplet is drawn in the electrowetting apparatus concerning Embodiment 2 of this invention. It is sectional drawing which expands and shows the structure of the fluid injection hole vicinity of the electrowetting apparatus concerning Embodiment 3 of this invention. (A)-(f) is a figure which shows an example of the manufacturing process of the upper board | substrate in the electrowetting apparatus concerning Embodiment 3 of this invention in order of a process. It is sectional drawing which expands and shows the structure of the fluid injection hole vicinity of the electrowetting apparatus concerning Embodiment 4 of this invention. It is sectional drawing which expands and shows the structure of the fluid injection hole vicinity of the electrowetting apparatus concerning Embodiment 5 of this invention. (A)-(f) is a figure which shows an example of the manufacturing process of the upper board | substrate in the electrowetting apparatus concerning Embodiment 5 of this invention in order of a process. It is sectional drawing which expands and shows the structure of the fluid injection hole vicinity of the electrowetting apparatus concerning Embodiment 6 of this invention. (A)-(c) is sectional drawing which shows the problem of the conventional electrowetting apparatus. (A) is a perspective view which shows the problem of the electrowetting apparatus shown to (a) of FIG. 18, (b) is a figure which shows the one part photograph of the electrowetting apparatus shown to (a). is there.

Hereinafter, embodiments of the present invention will be described in detail.

Embodiment 1
An embodiment of the present invention will be described below mainly with reference to FIGS.

In this embodiment, as an electrowetting device according to this embodiment, droplet driving (EWOD; Electrowetting-On-Dielectric (dielectric electrowetting)) is performed in an active matrix array using a thin film transistor (TFT). An active-matrix-type dielectric electrowetting-active-on-dielectric (AM-EWOD) apparatus will be described as an example.

Hereinafter, members having the same functions as those described in the background art will be described by adding the same reference numerals.

<Schematic configuration of electrowetting device 1>
FIG. 1A is an exploded perspective view showing a schematic configuration of a main part of an electrowetting device 1 according to the present embodiment, and FIG. 1B is an electrowetting device 1 according to the present embodiment. It is sectional drawing which expands and shows the structure of the fluid injection hole vicinity. In FIG. 1B, in order to show the configuration of the through hole 25, the ratio of each component, particularly the ratio of the through hole 25 is changed. For simplification, only one through hole 25 is shown. FIG. 2 is a cross-sectional view showing a schematic configuration of a pair of array elements in the electrowetting device 1 according to the present embodiment. FIG. 3 is a plan view showing an example of a schematic configuration of the thin film electronic circuit 12 in the electrowetting device 1 according to the present embodiment.

As shown in FIGS. 1A and 1B and FIG. 2, the electrowetting apparatus 1 includes a pair of substrates including a lower substrate 10 and an upper substrate 20 that are arranged to face each other.

As shown in FIGS. 1A and 1B to FIG. 3, the lower substrate 10 is a thin film in which a plurality of electrodes 13 (for example, the

electrodes

13a and 13b shown in FIG. 2) are formed on a support substrate 11. The electronic circuit 12 and the dielectric layer 14 are stacked in this order.

The surface of the lower substrate 10 is covered with a hydrophobic layer 15. In FIG. 1B, as an example, the case where the hydrophobic layer 15 is formed only on the surface facing the upper substrate 20 (that is, the upper surface) is shown as an example. However, the present embodiment is not limited to this, and the entire surface of the lower substrate 10 may be covered with the hydrophobic layer 15.

The plurality of electrodes 13 can be realized by patterning the uppermost layer of the support substrate 11 (which can also be interpreted as a part of the layers constituting the thin film electronic circuit 12). Such a configuration is called an electrowetting drive element. Note that both the electrode 13 associated with a specific array element and the node of the electric circuit directly connected to the electrode 13 may be referred to as an electrowetting drive element.

The thin film electronic circuit 12 is configured to drive each electrode 13.

Each electrode 13 is an AM (active matrix) electrode (array element electrode) and constitutes a part of the electrode array 16. As shown in FIGS. 1A and 3, the electrode array 16 has M × N array elements (M and N are arbitrary numbers).

As shown in FIG. 1B and FIG. 2, the dielectric layer 14 is disposed on the support substrate 11 so as to cover the plurality of electrodes 13. The dielectric layer 14 separates the electrode 13 from the hydrophobic layer 15 provided on the surface of the lower substrate 10 facing the upper substrate 20.

The upper substrate 20 has a configuration in which an electrode 22 is provided on the side of the support substrate 21 facing the lower substrate 10. The electrode 22 is covered with a hydrophobic layer 23.

The lower substrate 10 and the upper substrate 20 are bonded to each other by a sealing material 31 provided at the peripheral edge thereof to form a cell.

The gap between the lower substrate 10 and the upper substrate 20 may be held at a constant gap by the spacer 32.

The droplet 40 used for electrowetting is injected into a minute channel 30 (microchannel) formed by the gap between the lower substrate 10 and the upper substrate 20.

A part of the upper substrate 20 has an upper portion serving as a first liquid injection port (injection port) for injecting a droplet 40 (fluid) into a flow path 30 formed by a gap between the lower substrate 10 and the upper substrate 20. A plurality of through holes 25 penetrating the substrate 20 are provided. However, the present embodiment is not limited to this, and it is sufficient that at least one through hole 25 is provided.

The electrowetting device 1 includes an active region 2 and a frame region 3 (inactive region) provided outside the active region 2 as shown in FIG. The active region 2 is an AM (active matrix) electrode area in which a conductive film is patterned as the electrode 13 to form a two-dimensional array.

In the present embodiment, a case where the through hole 25 is provided near the boundary with the frame region 3 in the active region 2 of the upper substrate 20 will be described as an example. However, the present embodiment is not limited to this, and the through hole 25 may be provided in the frame region 3.

The hydrophobic layer 23 covers the surface of the upper substrate 20 except for the opening wall 25a in the through-hole 25 as shown in FIG. In FIG. 1B, as an example, a case where the entire surface of the upper substrate 20 excluding the opening wall 25a is covered with the hydrophobic layer 23 is shown as an example. However, the present embodiment is not limited to this, and the hydrophobic layer 23 is formed on the upper substrate 20 on the surface facing the lower substrate 10 (that is, the lower surface) and on the upper surface that is the opposite surface. What is necessary is just to be formed in the area | region which the droplet 40 contacts.

The opening wall 25a in the through hole 25 is formed of a hydrophilic layer 24 having a higher surface tension than the hydrophobic layer 15 in the lower substrate 10 and the hydrophobic layer 23 in the upper substrate 20.

As shown in FIG. 1B, the through hole 25 has a distance between the lower substrate 10 and the upper substrate 20 (distance between the opposing surfaces) as g1, and an opening diameter (diameter) of the through hole 25. Is preferably g2, g2> g1, more preferably g2 ≧ g1. Thereby, the droplet 40 injected from the through-hole 25 can be reliably brought into contact with the surface of the lower substrate 10 (that is, the surface of the dielectric layer 14 covered with the hydrophobic layer 23).

As the droplet 40, a conductive liquid such as an ionic liquid or a polar liquid is used. As the droplet 40, for example, liquid such as water, electrolytic solution (aqueous solution of electrolyte), alcohols, various ionic liquids can be used. Examples of the droplet 40 include, for example, a whole blood specimen, a bacterial cell suspension, a protein or antibody solution, and various buffer solutions.

Also, a non-conductive liquid 42 that is immiscible with the droplets 40 may be injected into the flow path 30. For example, the volume not occupied by the droplets 40 in the flow path 30 may be filled with the non-conductive liquid 42.

Therefore, a part of the electrowetting device 1 has a second liquid inlet (non-conductive liquid inlet) (not shown) as a fluid inlet for injecting the non-conductive liquid 42 into the flow path 30. It may be provided.

The second liquid inlet may be provided, for example, in a part of the frame region 3 in the upper substrate 20, and an opening is provided in a part of the sealing material 31 and is provided so as to extend from the opening. It may be.

As the nonconductive liquid 42, a nonpolar liquid (nonionic liquid) having a surface tension smaller than that of the droplet 40 can be used. Examples of the non-conductive liquid 42 include, for example, hydrocarbon solvents (low molecular hydrocarbon solvents) such as decane, dodecane, hexadecane, and undecane, oils such as silicone oil, and fluorocarbon solvents. Examples of the silicone oil include dimethylpolysiloxane. Note that only one type of non-conductive liquid 42 may be used, or a plurality of types may be appropriately mixed and used.

As the non-conductive liquid 42, a liquid having a specific gravity smaller than the specific gravity of the droplet 40 is selected. The specific gravity of the droplet 40 and the specific gravity of the non-conductive liquid 42 are not particularly limited as long as the relationship of the specific gravity of the non-conductive liquid 42 <the specific gravity of the droplet 40 is satisfied.

For example, when the droplet 40 is an aqueous electrolyte solution, the specific gravity of the droplet 40 is substantially the same as the specific gravity of water (≈1.0), and the non-conductive liquid 42 has a specific gravity of 1 such as silicone oil. Less than 0 liquid is used.

Further, it is preferable that the droplet 40 and the non-conductive liquid 42 have low viscosity. The droplet 40 may be diluted with water or the like so as to have a predetermined viscosity.

As shown in FIG. 1B, the droplet 40 contacts the hydrophobic layer 23 at a contact angle θ. The contact angle θ is indicated by the angle between the liquid surface and the solid surface at the boundary line where the solid surface is in contact with the liquid and gas, and the surface tension between the solid and the liquid (interface energy). ) Is γSL, the surface tension between the liquid and gas is γLG, and the surface tension between the solid and gas is γSG, the following equation (1)
cos θ = (γSG−γSL) / γLG (1)
Determined by

Here, the liquid is the droplet 40 and the solid is the hydrophobic layer 23. Similarly, when the time no voltage is applied to the

electrodes

13 and 22 and the contact angle between the droplet 40 and the hydrophobic layer 15 in (zero voltage) (initial contact angle) and theta _0, cos [theta] _0, the following equation (2)
cos θ ₀ = (γSG−γSL) / γLG (2)
Defined by

In some situations, the relative surface tension (ie, γSG, γSL, and γLG) of related substances may be a numerical value such that the right side of the above equation (2) is smaller than −1. This can typically occur when the volume not occupied by the droplets 40 in the flow path 30 is filled with, for example, oil as the non-conductive liquid 42.

In such a situation, the droplet 40 is not in contact with the hydrophobic layers 15 and 23 (hydrophobic surfaces), and the thin film of the nonconductive liquid 42 is interposed between the droplet 40 and the

hydrophobic layers

15 and 23. Can be formed.

As shown in FIG. 2, when the volume not occupied by the droplet 40 in the flow path 30 is filled with a non-conductive liquid 42 (for example, oil), the droplet 40 that is a liquid (Liquid) Assuming that the surface tension on the interface with the non-conductive liquid 42 that is the surrounding oil (Oil) is γLO, in the above formula (2), γLG and γSG can be replaced by γLO and γSO, respectively.

On the other hand, dependence of the contact angle theta of the droplet 40 which is supplied with droplets drive voltage VEW from equation Lippmann, the initial contact angle of the droplet 40 in the zero voltage and theta _0, it droplet 40 When the surface tension related to the interface with the non-conductive liquid 42 surrounding the surface is γLO, the following equation (3)
cos θ = cos θ ₀ + CVEW ² / 2γLO (3)
Indicated by

Thus, the contact angle θ is a measure of the hydrophobicity of the surface. It can be defined that the surface is hydrophilic when θ <90 degrees and the surface is hydrophobic when θ> 90 degrees. The degree of hydrophobicity or hydrophilicity is defined according to the difference between the contact angle θ and 90 degrees. FIG. 1B shows a droplet 40 that is in contact with the surface of the hydrophobic layer 23 having a hydrophobic surface at a contact angle θ in a static equilibrium state.

When the electrowetting device 1 is driven, an EW drive voltage (for example, VT, V0, and V00 shown in FIG. 2) is applied to each of different electrodes (for example, the

electrodes

13a and 13b). The hydrophobicity of the

hydrophobic layers

15 and 23 is effectively controlled by the electric force generated by the voltage application. The droplet 40 moves horizontally toward a region with higher hydrophilicity (in other words, a region with lower hydrophobicity).

By disposing different electrodes (

electrodes

13a and 13b) such that different EW driving voltages (for example, V0 and V00) are applied, the droplet 40 is allowed to flow between the lower substrate 10 and the upper substrate 20 with each other. Can be moved laterally along the opposite surfaces (surfaces of the hydrophobic layers 15 and 23).

A transparent insulating substrate is used for the

support substrates

11 and 21. The support substrates 11 and 21 can be formed of, for example, a glass substrate. However, in this embodiment, since the

hydrophobic layers

15 and 23 and the hydrophilic layer 24 are formed on the surfaces of the

support substrates

11 and 21, a substrate such as a plastic substrate or a ceramic substrate is used as the

support substrate

11 or 21, respectively. May be.

The

hydrophobic layers

15 and 23 and the hydrophilic layer 24 can be formed by using an appropriate surface coating method such as a dipping method, a spin coating method, a CVD method, or an electrodeposition method.

The droplet 40 drawn into the gap between the lower substrate 10 and the upper substrate 20 is given to each electrode 13 constituting the electrode array 16 in the active region 2 (region where the electrode array 16 is an AM electrode formation area). A predetermined voltage is applied in the sequence. As a result, a part of the droplet 40 (a predetermined amount of smaller droplets 41 and minute droplets shown in FIGS. 2 and 3) is torn off (separated) and carried to the predetermined flow path 30. It is.

Although only one droplet 41 is illustrated in FIG. 3, a plurality of droplets 41 may be disposed between the lower substrate 10 and the upper substrate 20.

Each array element of the electrode array 16 includes an array element circuit 17 in order to control the potential of the corresponding electrode 13.

The thin film electronic circuit 12 is also provided with an integrated row driving circuit 51 and column driving circuit 52. The row drive circuit 51 and the column drive circuit 52 supply control signals to the array element circuit 17.

Further, the thin film electronic circuit 12 may include a serial interface 53 that processes a serial input data stream and writes a necessary voltage to the electrode array 16. In addition, the thin film electronic circuit 12 may include a voltage supply interface 54 that supplies a corresponding supply voltage, a drive voltage for the upper substrate 20, and other required voltages. Since the thin film electronic circuit 12 includes the serial interface 53 and the voltage supply interface 54, even when the size of the electrode array 16 is large, a connection wire 55 between the lower substrate 10 and an external drive electronic circuit (not shown). And the number of power supplies and the like can be made relatively small.

The array element circuit 17 may additionally include a sensor function. For example, the array element circuit 17 includes a mechanism for detecting the presence of the droplet 41 at the position of each array element in the electrode array 16 and detecting the size of the droplet 41. Also good.

For this reason, the thin film electronic circuit 12 may include a column detection circuit (not shown) for reading sensor data from each array element and integrating the data into one or more serial output signals. The serial output signal may be given via the serial interface 53 and output from the electrowetting device 1 by one or more connection wires 55.

The array element circuit 17 is configured so that the droplet driving voltage VEW can be applied to the droplet 40, and may include a memory element, an inverting circuit, and the like (not shown). The memory elements include, for example, a column write line extending from the column driving circuit 52 (may be common to array elements in the same column), a row selection line extending from the row driving circuit 51 (to the array elements in the same row). May be included), a capacitive memory device, a DC (direct current) supply voltage Vref, a switch transistor, and the like. The inversion circuit may include a plurality of analog switches, supply voltages V1 and V2 (may be common to all array elements), an inverter, and the like.

In the EWOD operating mechanism, the contact angle of the droplet with respect to the hard surface depends on the square of the operating voltage, and the direction of the applied voltage is not uniquely important. Therefore, EWOD can be carried out by any of the AC (alternating current) drive method and the DC drive method.

When the AC driving method is used, the voltage VT is applied to the electrode 22 of the upper substrate 20 as shown in FIG. For simplification, it is assumed that the upper substrate 20 is grounded. When the electrode 13 forming the EWOD drive electrode is set to a low level, the voltage VT is also applied to the EWOD drive electrode. When the EWOD drive electrode is set high, the voltage V1 is applied to the EWOD drive electrode. V1 is a rectangular waveform with an amplitude of 2VA, where the high level is + VA and the low level is -VA. When the frequency of the AC waveform is lower than the intrinsic droplet reaction frequency determined by the conductivity of the

droplets

40 and 41, the droplet driving voltage VEW is the root mean square of the voltage difference (= VA) from V1 to VT (= VA). rms).

Note that, by appropriate configuration and operation of the thin film electronic circuit 12, for example, electrowetting drive voltages such as VT, V0, and V00 may be applied to the electrode 13a and the electrode 13b, respectively. Thereby, the hydrophobicity of the hydrophobic layer 15 can be controlled, and the movement of the

lateral droplets

40 and 41 in the flow path 30 between the lower substrate 10 and the upper substrate 20 becomes easy.

<Method of manufacturing electrowetting device 1>
Next, a method for manufacturing the electrowetting device 1 according to the present embodiment will be described with reference to FIGS. 1 (a) and 1 (b) to FIGS. 5 (a) to 5 (d).

4A to 4D are diagrams showing a part of the manufacturing process of the upper substrate 20 in the electrowetting apparatus 1 according to the present embodiment in the order of processes.

First, as shown in FIG. 4A, a plurality of mother substrates 61 provided with a solid conductive film (not shown) are bonded together with a temporary fixing adhesive 62 and cured, so that the mother substrate 61 The adhesive body 60 in which a plurality of sheets are bonded together is formed. In the present embodiment, as an example, a large-sized glass substrate having a thickness of 0.7 mm in which an ITO (indium tin oxide) film is provided in a solid form on the entire surface of one main surface is used as the mother substrate 61. In addition, the temporary fixing adhesive 62 is made by Denki Kagaku Kogyo Co., Ltd. (DENKA), which can be easily cured with warm water (recommended temperature: 80 to 90 ° C) without using an organic solvent. TEMPLOC (registered trademark) was used.

Next, in order to protect the outermost surface of the adhesive 60, a protective sheet 63 is attached to the upper surface of the uppermost mother board 61 and the lower surface of the lowermost mother board 61. Instead of the protective sheet 63, a dummy substrate (for example, a dummy glass substrate) may be used. In this case, the dummy substrate is attached to the mother substrate 61 using the same temporary fixing adhesive as the temporary fixing adhesive for attaching the mother substrates 61 to each other. Thereby, since the dummy substrate can be peeled off in the step of peeling the mother substrates 61 from each other, a separate step for removing only the protective sheet 63 becomes unnecessary.

Subsequently, a predetermined number of through holes 60a having a predetermined opening diameter g2 (see FIG. 1B) are provided at predetermined positions of the adhesive body 60 in a state where the protective sheet 63 is provided. It is formed so as to penetrate the bottom surface from the top surface. In this case, the through hole 60a is formed using a precision drill or a laser drill dedicated to glass. And the adhesive body 60 in which the through-hole 60a was formed is divided | segmented into predetermined 1 chip size. Hereinafter, the adhesive body 60 divided into one chip size is referred to as an adhesive body 60A. Further, the mother substrate 61 divided into one chip size is referred to as a chip 61A.

Next, as shown in FIG. 4 (b), the adhesive body 60A cut out to one chip size is immersed in a container 64 filled with the resist solution 65, and includes the inside of the through hole 60a. The whole 60 is covered with a resist solution 65. As the resist solution 65 used here, a diluted solution obtained by diluting a positive resist “TFR1000” (trade name) manufactured by Tokyo Ohka Kogyo Co., Ltd. with a predetermined solvent is used, but is not limited thereto.

Subsequently, the adhesive 60A coated with the resist liquid 65 is taken out from the container 64, and the adhesive 60A is heated at 110 ° C. for 3 minutes to cure the resist liquid 65 to obtain a resist layer 65A.

It should be noted that the temperature and time for curing the resist solution 65 are not limited to the above temperature and time, and may be appropriately modified according to the type of the resist solution 65, and are not particularly limited.

Thereafter, as shown in FIG. 4C, the protective sheet 63 is peeled off from the adhesive 60A having the through-hole 60a and having the resist layer 65A formed on the surface.

Next, as shown in FIG. 4D, the adhesive 60A from which the protective sheet 63 has been peeled is immersed in warm water of about 80 to 90 ° C., and the chips 61A in the adhesive 60A are bonded. The fixing adhesive 62 is dissolved to separate the mother substrates 61. Thereby, the chip 61A having the through hole 60a and having the through hole 60a covered with the resist layer 65A is formed.

When the outermost surface of the adhesive 60A is protected using a dummy substrate instead of the protective sheet 63, the process shown in FIG. 4C is unnecessary, and in the process shown in FIG. The dummy substrate is separated together with the chip 61A.

The chip 61A thus obtained is subjected to the surface treatment shown in FIGS. 5A to 5D, and finally becomes the upper substrate 20.

5A to 5D are views showing the surface treatment process of the upper substrate 20 in the order of the processes.

In the following, as shown in FIG. 5A, a mother substrate 61 (chip 61A) provided with a solid conductive film (ITO film) and divided into one chip size is used as an electrode made of the conductive film. The support substrate 21 provided with 22 will be described. Further, the through hole 60a will be described as the through hole 25.

The individual chips 61A separated in FIG. 4D are cleaned by ultrasonic cleaning and plasma ashing, and chipping pieces generated during processing of the through hole 60a used as the through hole 25 are removed. Remove.

Next, the surface of the chip 61A where the electrode 22 is formed is subjected to a hydrophobic treatment.

For example, a 1 wt% diluted solution of “CYTOP (registered trademark) -CTL107MK” (trade name) manufactured by AGC Asahi Glass Co., Ltd., which is a perfluoroamorphous resin, is used as a hydrophobic treatment agent. The hydrophobic treatment agent is dip-coated on the support substrate 21 by immersing the chip 61A shown in the hydrophobic treatment agent.

Specifically, the support substrate 21 provided with the electrode 22 is immersed in a container (not shown) filled with the hydrophobic treatment agent at an immersion speed of 5 mm / sec, an immersion time of 60 sec, and a lifting speed of 1 mm / sec. Thereby, as shown in FIG. 5B, a hydrophobic layer 23 (Cytop film) having a thickness of 50 nm is formed on the entire surface of the chip 61A including the resist layer 65A inside the through hole 25.

Next, the above-mentioned chip 61A on which the hydrophobic layer 23 is formed is immersed in “SPX” (trade name, 2-aminoethanol) manufactured by Hayashi Junyaku Kogyo Co., Ltd., and subjected to ultrasonic waves for 5 minutes at room temperature. The resist layer 65A in the through hole 25 and the hydrophobic layer 23 on the resist layer 65A are peeled off. Thereby, as shown in FIG. 5C, the tip 61A is in a state where the hydrophobic layer 23 is not formed only in the through hole 25.

Subsequently, as shown in FIG. 5D, a hydrophilic layer 24 is formed on the opening wall 25a of the through-hole 25 where the hydrophobic layer 23 is not formed. Thereby, the upper substrate 20 according to the present embodiment is completed.

In the step shown in FIG. 5D, for example, a betaine group-containing hydrophilic polymer having a terminal silanol group, which is diluted with water so as to have a predetermined viscosity as a hydrophilic polymer aqueous solution inside the through-hole 25. (Osaka Organic Chemical Co., Ltd. “LAMBIC-500WP”, trade name) is added dropwise. Thereby, the hydrophilic polymer 24 does not adhere to the portion of the chip 61A where the hydrophobic layer 23 other than the opening wall 25a is formed, and the hydrophilic layer 24 is formed only on the opening wall 25a. That is, the opening wall 25a is in a state where a hydrophilic coating is applied.

As described above, when the hydrophilic layer 24 is formed on the opening wall 25a of the through hole 25 of the upper substrate 20, the liquid droplet 40 is not only quickly taken into the through hole 25 but also a fluid (droplet) of a specimen or a reagent. ) Can be prevented from being directly adsorbed on the surface of the support substrate 21, for example, a glass surface.

The lower substrate 10 can be formed in the same manner as before. That is, each layer (each component) in the lower substrate 10 can be formed by a known method.

In the present embodiment, the through hole 25 is provided in the active area 2. However, as described above, the through hole 25 may be provided in the frame area 3. When the through-hole 25 is provided in the frame region 3, in the step of forming the electrode 13, a lead-in electrode connected to the electrode 13 in the active region 2 (AM electrode area) is provided from directly below the through-hole 25.

Further, the lower substrate 10 may include a high resolution electrode array and a low resolution electrode array. In this case, a high resolution electrode array is formed in the active region 2. The low resolution electrode array (including electrode pads larger than the high resolution electrode array) can be used to draw and control the relatively large droplets 40 injected into the cell from the through holes 25 into the flow path 30.

The electrode 13 provides a straight path (flow path) for tearing (separating) a smaller droplet 41 from a relatively large droplet 40 injected into the cell from the through hole 25, Then, the active region 2 is moved to the active region 2 provided with the main electrode array 16 composed of a high resolution electrode array.

The high-resolution electrode array (including an electrode pad smaller than the low-resolution electrode array) splits a relatively large droplet 40 injected from the through-hole 25 into smaller droplets 41 for subsequent operations (chemical analysis, etc.). ).

In the lower substrate 10, for example, a 1 wt% diluted solution of “Cytop CTL107MK” as a hydrophobic treatment agent is added to the lower substrate 10 on which the dielectric layer 14 is formed and before the hydrophobic layer 15 is formed. A hydrophobic layer 15 (cytop film) can be formed on the dielectric layer 14 by slit coating or spin coating on the formation surface of the body layer 14. Of course, a 1 wt% diluted solution of “Cytop CTL107MK”, for example, as the hydrophobic treatment agent is dip coated in the same manner as the upper substrate 20, so that the hydrophobic layer 15 similar to the hydrophobic layer 23 is formed on the surface of the lower substrate 10. (Cytop film) may be formed.

Thereafter, as shown in FIG. 1B, the lower substrate 10 and the upper substrate 20 are bonded together with a sealing material 31 so that the electrode 13 and the electrode 22 face each other. Thereby, the electrowetting device 1 (the cell) according to the present embodiment is manufactured.

<Droplet injection method>
Next, regarding the method of injecting the droplet 40 and the non-conductive liquid 42 into the electrowetting device 1, FIG. 1 (b), FIG. 6 (a) to (e) and FIG. 7 (a) to FIG. This will be described below with reference to (c).

6 (a) to 6 (e) are cross-sectional views sequentially showing how the droplets 40 are drawn into the electrowetting device 1. FIG. FIGS. 7A to 7C are perspective views sequentially showing how the droplets 40 are drawn into the electrowetting device 1.

First, as shown in FIG. 1B, FIG. 6A, and FIG. 7A, for example, a predetermined amount of droplet 40 is dropped into the through-hole 25 of the upper substrate 20 by a pipette or the like. . As shown in FIGS. 1B and 6A, a hydrophobic layer 23 is formed on the upper surface of the upper substrate 20 to which the dropped droplet 40 is grounded (contacted), while the through-hole 25 is formed. On the surface of the opening wall 25a, a hydrophilic layer 24 is formed by superhydrophilic coating. For this reason, the dropped droplet 40 naturally enters the through-hole 25 by its own weight.

Hydrophobic layers

15 and 23 are formed on the opposing surfaces of the lower substrate 10 and the upper substrate 20, respectively. For this reason, the dropped liquid droplet 40 fills the through-hole 25 with the liquid droplet 40, and after the liquid droplet 40 that has entered the through-hole 25 comes into contact with the surface of the lower substrate 10, no more. , Will not enter the cell.

As shown in FIG. 18C, when the hydrophobic layer 23 is not formed on the upper surface of the upper substrate 20, the droplet 40 that has come into contact with the upper surface of the upper substrate 20 wets and spreads on the upper surface of the upper substrate 20. Since the force to rip off always works, it is difficult to draw the droplet 40 into the flow path 30 by the electrowetting operation.

In contrast, in the present embodiment, the droplet 40 is grounded by its own weight on the surface of the lower substrate 10, and the hydrophobic layer 23 is provided on the upper surface of the upper substrate 20. For this reason, the droplet 40 does not spread on the upper substrate 20 and tries to keep the surface area as small as possible. The electrode 13 covered with the dielectric layer 14 having the hydrophobic layer 15 on the surface is present immediately below the droplet 40 grounded by its own weight. For this reason, by sequentially applying a voltage to the plurality of electrodes 13 immediately below the ground plane of the droplet 40 on the lower substrate 10, the droplet 40 is effectively drawn in a predetermined direction by electrowetting.

At this time, the liquid droplet 40 that is grounded to the lower substrate 10 has a hydrophilic layer 24 formed on the surface of the opening wall 25 a in the through hole 25, so that the liquid 40 located in the through hole 25 is included in the liquid droplet 40. The volume of the drop 40b is always maintained.

Therefore, of the droplets 40, the droplet 40 c positioned below the through-hole 25, which has reached the channel 30, moves in the channel 30 along the surface of the lower substrate 10 by electrowetting. As shown in FIGS. 6B and 6C, the volume of the droplet 40a that protrudes outside the through-hole 25 of the upper substrate 20 is reduced. Decrease gradually. Then, when all of the droplets 40a protruding outside the through-hole 25 of the upper substrate 20 disappear as shown in FIGS. 6D and 7B, the drawing by electrowetting stops.

The amount of the droplet 40 dropped into the through-hole 25 is set so that a part of the droplet 40 protrudes from the surface of the upper substrate 20 when the penetration of the droplet 40 stops in the cell as described above. Is set. The protruding portion of the droplet 40 is brought into contact with the hydrophobic layer 23 at a high contact angle θ by the hydrophobic layer 23 formed on the upper surface of the upper substrate 20.

The drop amount of the droplet 40 to the through-hole 25 is at least the amount of the droplet that needs to be drawn into the cell + the amount of the droplet in the through-hole 25 (that is, the volume amount of the droplet 40b) + the penetration. It is sufficient that the droplet protruding from the mouth 25 has a volume equal to or larger than the volume indicated by the amount of droplet required for grounding the lower substrate 10 (that is, the volume of the droplet 40c).

After the drawing of the droplet 40 is stopped as shown in FIG. 6 (d) and FIG. 7 (b), as shown in FIG. 6 (e) and FIG. By applying a predetermined voltage to the predetermined electrode 13 which is an AM electrode, a predetermined amount of minute droplets 41 are separated from the drawn droplets 40 and moved to the predetermined flow path 30.

As described above, according to the present embodiment, the droplets 40 dropped onto the through-hole 25 naturally enter the hydrophilic region (that is, the formation region of the hydrophilic layer 24) in the through-hole 25 in the hydrophilic region. A certain amount of liquid is stored according to the volume (for example, when all the opening walls 25a of the through-hole 25 are the hydrophilic layer 24 as described above, the volume of the through-hole 25).

For this reason, according to the present embodiment, just by dropping an appropriate amount of the droplet 40 into the through-hole 25, a certain amount of the droplet 40 is naturally sucked into the channel 30 (microchannel).

For this reason, according to the present embodiment, the droplets 40 need only be appropriately dropped or continuously flowed from above the through hole 25, and no complicated fluid (droplet) injection mechanism is required.

Therefore, according to the present embodiment, the droplet 40 can be injected into the flow path 30 (that is, the electrowetting device 1) without requiring a complicated fluid (droplet) injection mechanism. .

Note that a series of operations (steps) from (d) in FIG. 6 to (e) in FIG. 6 are performed using the electrowetting operation of the electrode 13 as an AM electrode in these drawings. This operation does not necessarily have to be performed on the AM electrode. For example, by providing a lead-in electrode connected to the AM electrode in the active region 2 (AM electrode area), the steps up to the step shown in FIG. 6D can be performed using the lead-in electrode. Good.

The non-conductive liquid 42 is injected into the cell from a second liquid injection port (not shown) separately provided in the electrowetting device 1 after the droplet 40 is injected into the cell by the above method. Note that before injecting the droplet 40 into the cell by the above-described method, the non-conductive liquid 42 may be injected from a second liquid inlet (not shown) so as to fill the channel 30.

FIG. 8A is a perspective view illustrating a state in which the droplet 40 is drawn into the electrowetting device 1 according to the present embodiment, and FIG. 8B is illustrated in FIG. It is a figure which shows the photograph of the principal part of the electrowetting apparatus. 8A and 8B and FIG. 19A and FIG. 19B show the comparison results under the same conditions.

As shown in FIGS. 18 (a) to 18 (c) and FIGS. 19 (a) and 19 (b), the droplets 40 are conventionally placed in the through-hole 25 as in FIGS. The liquid droplet 40 is not drawn into the electrowetting device by simply dropping the liquid. In particular, as shown in FIGS. 18 (a) and 18 (b) and FIGS. 19 (a) and 19 (b), the contact surface with the droplet 40 in the path from the through hole 25 into the flow path 30 is all hydrophobic. In the case of a surface, the droplet 40 is ejected from the through hole 25.

However, according to the present embodiment, as shown in FIGS. 19A and 19B, the droplet 40 can be injected into the cell without providing a special droplet (fluid) injection mechanism. It became.

<Application>
The electrowetting device 1 according to the present embodiment is used for various applications in which the user needs to inject the droplet 40 into the electrowetting device 1 from the through hole 25, for example, molecular nucleic acid coefficient, fluid viscosity, pH, chemistry. It can be particularly suitably used for various measuring devices and analytical devices such as binding coefficient and enzyme reaction kinetics. Examples of other application examples of the electrowetting device 1 include, for example, analysis through capillary electrophoresis, isoelectric focusing, immunoassay, enzyme measurement, flow cytometry, and mass spectrometry. Protein sample injection, PCR amplification, DNA analysis, cell manipulation, cell separation, cell pattern formation, chemical gradient formation, and the like. Many of these applications are effective for clinical diagnostic methods.

[Embodiment 2]
The present embodiment will be described below with reference to FIGS. In the present embodiment, differences from the first embodiment will be described, and components having the same functions as those used in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted. .

<Schematic configuration of electrowetting device 1>
FIG. 9 is an enlarged cross-sectional view showing the configuration in the vicinity of the fluid injection hole of the electrowetting device 1 according to the present embodiment.

As shown in FIG. 9, in the electrowetting device 1 according to the present embodiment, not only the opening wall 25a of the through hole 25 but also the region connected from the through hole 25 to the facing surface (lower surface) of the lower substrate 10 is a hydrophilic surface. Except for this point, it is the same as the electrowetting device 1 according to the first embodiment.

That is, as shown in FIG. 9, the electrowetting device 1 according to the present embodiment has a hydrophobic layer 15 in a certain area around the through hole 25 in the through hole 25 of the upper substrate 20 and on the lower surface of the upper substrate 20. -The hydrophilic layer 24 whose surface tension is higher than 23 is formed.

A hydrophobic layer 23 is formed in a region other than the region where the hydrophilic layer 24 is formed on the lower surface of the upper substrate 20 and in a region where the

droplets

40 and 41 are in contact with each other.

The formation region of the hydrophilic layer 24 around the through hole 25 on the lower surface of the upper substrate 20 is a concentric area centering on the through hole 25 in plan view.

In the present embodiment, a surface area facing the lower substrate 10 having a diameter (g3) larger than the opening diameter (g2, diameter) of the through-hole 25 by a predetermined amount is a hydrophilic surface.

<Method of manufacturing electrowetting device 1>
The manufacturing method of the electrowetting device 1 is the same as the manufacturing method of the electrowetting device 1 according to the first embodiment except for the manufacturing process of the upper substrate 20. The manufacturing method of the upper substrate 20 is substantially the same as the manufacturing method of the upper substrate 20 according to the first embodiment. However, in the manufacturing process of the upper substrate 20, as described above, the upper substrate 20 is finally formed on the upper substrate 20. This is different from the first embodiment in that a process for expanding the hydrophilic surface is newly added.

The newly added process is a concentric circle centering on the formation position of the through-hole 60a on the conductive film forming surface side of the mother substrate 61 before forming the adhesive body 60 in the first embodiment, and is a through-hole to be formed. In this step, a region having a diameter larger than the mouth 60a by a predetermined amount is subjected to hydrophilic treatment.

In this embodiment, first, the through hole 60a (through hole 25) is scheduled to be formed on the conductive film forming surface of the mother substrate 61 (that is, the surface corresponding to the inside of the cell, which is the electrode 22 forming surface of the upper substrate 20). A circular resist pattern 71a (see FIG. 10C) having a predetermined diameter larger than the diameter of the through hole 60a (through hole 25) is formed in a concentric area centering on the area. By providing, the formation area of the hydrophilic layer 24 is expanded.

Hereinafter, a more specific description will be given with reference to (a) to (c) of FIG.

10 (a) to 10 (c) show a region where the through hole 60a is to be formed on the solid conductive film (not shown) of the mother substrate 61 which will eventually become the electrode 22 (hereinafter referred to as “the through hole formation scheduled region”). This shows a step of forming a resist pattern 71a in a concentric region 61b having a diameter g3 (g3> g2) centering around 61a ”.

First, as shown in FIG. 10A, a resist layer 71 is formed on a conductive film (not shown) of the mother substrate 61 that will eventually become the electrode 22.

Specifically, a resist solution made of a photosensitive resist is spin-coated on a conductive film (not shown) of the mother substrate 61 so that the resist layer 71 to be formed has a thickness of less than 1 μm. In this embodiment, a dilute solution obtained by diluting a positive resist “TFR1000” (trade name) manufactured by Tokyo Ohka Kogyo Co., Ltd. with a predetermined solvent is used as the resist solution, and the rotational speed is 1000 to 2000 rpm and the temperature is 110 ° C. Spin coating was performed for 3 minutes.

Next, as shown in FIG. 10B, from the upper surface side of the resist layer 71 in the mother substrate 61, the resist layer 71 is applied to the solid substrate (not shown) of the mother substrate 61 using a photomask 72. An area on the film other than the concentric area 61b having a diameter g3, which is centered on the through-hole formation scheduled area 61a, is exposed. For exposure, i-line (ultraviolet light having a wavelength of 365 nm, enhancement condition: 100 mJ / cm ² ) was used.

Next, by developing the resist layer 71, the exposed resist layer 71 was dissolved and removed. For development, TMAH (tetramethylammonium hydroxide) diluted to 2.38% was used as a developer, and the development was performed at room temperature for 100 minutes. A rinse solution or pure water was used for cleaning the mother substrate 61 after development.

Thereby, a resist pattern 71a composed of the resist layer 71 was formed in the region 61b. Here, the case where a positive resist is used as the photosensitive resist has been described as an example, but it goes without saying that a negative resist may be used as the photosensitive resist. When a negative resist is used, the exposed portion is cured and removed when the unexposed portion is developed. For this reason, a photomask 72 having a shape different from that in FIG.

In this way, a plurality of mother substrates 61 in which a resist pattern 71a is formed in a concentric region 61b having a diameter g3 centering on the through-hole formation planned region 61a on the solid conductive film of the mother substrate 61 are provided. Then, as in the first embodiment, the adhesive body 60 is formed.

Thereafter, by performing the same processing as that shown in FIGS. 4A to 4D in the first embodiment, the inside of the through hole 60a is covered with the resist layer 65A, and the above-described through hole is formed on the lower surface of the chip 61A. A region 61c between the mouth 60a and the region 61b (see FIG. 10C, a through-hole 60a is formed in the through-hole formation scheduled region 61a, and a region 61c between the through-hole 60a and the region 61b). Then, the chip 61A on which the resist pattern 71a is formed is formed.

Next, by performing the same processing as the processing shown in FIGS. 5A to 5D using the chip 61A, as shown in FIG. 9, the inside of the through hole 25 of the upper substrate 20 and the upper portion A constant region around the through hole 25 on the lower surface of the substrate 20 (that is, a region corresponding to the region 61c, specifically, a concentric circle having a diameter larger than that of the through hole 25 centered on the through hole 25). The upper substrate 20 in which the hydrophilic layer 24 is formed in the region) can be formed.

Thereafter, the upper substrate 20 is bonded to the lower substrate 10 in the same manner as in the first embodiment, whereby the electrowetting device 1 according to the present embodiment is manufactured.

<Droplet injection method>
(A) to (e) of FIG. 11 are cross-sectional views sequentially showing how the droplets 40 are drawn into the electrowetting device 1 according to the present embodiment.

The method for injecting the droplet 40 and the non-conductive liquid 42 into the electrowetting device 1 is the same as that in the first embodiment.

However, in this embodiment, as described above, the hydrophilic layer 24 is formed around the through hole 25 on the lower surface of the upper substrate 20, so that the through hole is formed as shown in FIG. The droplet 40 that has entered the through-hole 25 by its own weight due to the hydrophilic layer 24 in the layer 25 wets and spreads along the hydrophilic layer 24 on the lower surface of the upper substrate 20. Therefore, according to the present embodiment, as shown in FIGS. 9 and 11A to 11C, more droplets 40 dropped into the through hole 25 are drawn into the cell, and the lower substrate 10 is reliably grounded (contacted) with the surface of the substrate 10, and the contact area of the droplet 40 with the upper substrate 20 (approximately equal to the area of a circle with a diameter g3) and the contact area with the lower substrate 10 (grounding area) are increased. .

For this reason, according to the present embodiment, the same effects as those of the first embodiment can be obtained, and the effect of suppressing the occurrence of a problem that the liquid droplet 40 injected into the through-hole 25 does not enter the flow path 30 is high. .

In the present embodiment, as described above, the hydrophilic layer 24 is provided around the through hole 25 on the lower surface of the upper substrate 20, and the droplets 40 are actively wetted and spread on the lower surface of the upper substrate 20. As described above, the droplet 40 is reliably grounded (contacted) with the surface of the lower substrate 10. For this reason, in this embodiment, the same combination as in the first embodiment can be selected for the droplet 40 and the non-conductive liquid 42. However, the specific gravity of the non-conductive liquid 42 is less than the specific gravity of the droplet 40. There is no need to have a relationship. For this reason, according to this embodiment, the freedom degree of the material selection concerning the combination of the droplet 40 and the nonelectroconductive liquid 42 can be improved.

[Embodiment 3]
This embodiment will be described below with reference to FIGS. 12 and 13 (a) to (f). In the present embodiment, differences from the first embodiment will be mainly described, and components having the same functions as the components used in the first embodiment are denoted by the same reference numerals, and the description thereof will be given. Is omitted.

<Schematic configuration of electrowetting device 1>
FIG. 12 is an enlarged cross-sectional view showing the configuration near the fluid injection hole of the electrowetting device 1 according to the present embodiment.

As shown in FIG. 12, in the electrowetting device 1 according to the present embodiment, the support substrate 21 is a hydrophobic substrate 21A made of a hydrophobic base material, has a hydrophobic surface, and the hydrophobic substrate 21A itself. Is the same configuration as the electrowetting device 1 according to the first embodiment except that is a hydrophobic layer on the upper surface of the upper substrate 20.

That is, in the electrowetting device 1 according to this embodiment, the upper surface of the upper substrate 20, that is, the upper surface of the support substrate 21 is not separately subjected to hydrophobic treatment. That is, the coating layer made of the hydrophobic treatment agent is not formed on the upper surface of the support substrate 21. For this reason, in this embodiment, the hydrophobic layer 23 is not provided on the upper surface of the support substrate 21, and the hydrophobic layer 23 is provided on the lower surface of the upper substrate 20 (that is, the electrode 22 of the upper substrate 20 located in the cell). Are formed only on the formation surface).

As the hydrophobic base material, for example, a plastic base material is preferably used, but is not limited thereto.

The hydrophobic substrate 21A is preferably a hydrophobic substrate having a contact angle θ of the droplet 40 of 80 degrees or more, more preferably 90 degrees or more. For example, the water contact angle θ is 80 degrees or more, more preferably 90 degrees or more. And a hydrophobic substrate.

Examples of the hydrophobic base material used for the hydrophobic substrate 21A include plastic base materials made of plastics such as silicon rubber, polytetrafluoroethylene, polypropylene, polytetrafluoroethylene, polyethylene, and polystyrene. Among these, for example, silicon rubber, polytetrafluoroethylene, polypropylene, and polytetrafluoroethylene are preferable.

Hereinafter, as an example, the contact angle θ of water at 20 ° C. and / or the surface tension at 20 ° C. of the plastic substrate is shown.

Silicon rubber (contact angle θ: 90 deg), polytetrafluoroethylene (contact angle θ: 104 deg), polypropylene (contact angle θ: 91 deg, surface tension: 31 dyne / cm), polytetrafluoroethylene (contact angle θ: 114 deg) Surface tension: 18.5 dyne / cm), polyethylene (when density is 0.92, contact angle θ: 81 deg, surface tension: 32 dyne / cm), polystyrene (contact angle θ: 84 deg, surface tension: 33 dyne / cm)
Hereinafter, in this embodiment, the case where the hydrophobic substrate 21A is formed by resin injection molding will be described as an example.

When the hydrophobic substrate 21A is formed by resin injection molding, the through hole 25 can be formed simultaneously with the molding of the hydrophobic substrate 21A. In the present embodiment, a plastic substrate having a through hole 25 provided in advance is used as the hydrophobic substrate 21A.

<Method of manufacturing electrowetting device 1>
The manufacturing method of the electrowetting device 1 according to the present embodiment is the same as the manufacturing method of the electrowetting device 1 according to the first embodiment, except for the manufacturing process of the upper substrate 20. Therefore, only the method for manufacturing the upper substrate 20 will be described below.

FIGS. 13A to 13F are diagrams showing an example of the manufacturing process of the upper substrate 20 in the electrowetting apparatus 1 according to the present embodiment in the order of processes.

In this embodiment, first, as shown in FIG. 13A, a resin (plastic) hydrophobic substrate 21 A provided with a predetermined through-hole 25 is formed by injection molding as the support substrate 21. . In the present embodiment, a perforated substrate made of polypropylene resin having a low surface tension of the material itself is formed as the hydrophobic substrate 21A.

Next, as shown in FIG. 13B, the electrode 22 is formed on one surface (surface disposed on the cell inner side) of the hydrophobic substrate 21A.

For example, “Denatron” (registered trademark), which is a coating-type electrode material manufactured by Nagase ChemteX Corporation, is printed on the one surface of the hydrophobic substrate 21A in a solid shape by screen printing. Form.

Thereafter, as shown in FIG. 13C, a hydrophilic layer 24 is formed on the entire surface of the hydrophobic substrate 21A on which the electrode 22 is formed by a dip coating method.

Specifically, the hydrophobic substrate 21A on which the electrode 22 is formed is a water-soluble photosensitive resin-coated hydrophilic coating material such as “BIOSURFINE (registered trademark) -AWP” (manufactured by Toyo Gosei Co., Ltd.). The hydrophilic layer 24 is formed by dipping the whole in an aqueous solution and dip-coating the whole.

Next, as shown in FIG. 13D, the hydrophobic substrate 21 A is masked with a photomask 72 that shields light other than the through-hole 25, and the through-hole 25 is irradiated with ultraviolet rays to irradiate the through-hole. The hydrophilized coating material (hydrophilic layer 24) in 25 is gelled.

Thereafter, as shown in FIG. 13 (e), the hydrophobic substrate 21A is washed with water, and the non-gelled coating portion (hydrophilic layer 24) is dissolved and peeled off. Thereby, the gel-like hydrophilic layer 24 remains only in the through hole 25.

Finally, by performing hydrophobic treatment, as shown in FIG. 13 (f), the surface on which the electrode 22 is formed on the hydrophobic substrate 21A in which the hydrophilic layer 24 is provided in the through hole 25 (that is, inside the cell). The hydrophobic layer 23 is formed on the electrode surface).

In this embodiment, a 1 wt% diluted solution of “Cytop (registered trademark) -CTL809A” manufactured by AGC Asahi Glass Co., Ltd., which is a perfluoroamorphous resin, is used as the hydrophobic treatment agent. By coating the surface of the hydrophobic substrate 21A on which the electrode 22 is formed with a slit coater, a hydrophobic layer 23 (Cytop film) having a thickness of 50 nm is formed only on the electrode surface.

According to the present embodiment, the process described above forms the hydrophilic layer 24 composed of a gelled layer of the hydrophilic coating material only in the through-hole 25, and not only the droplet 40 is quickly taken into the through-hole 25, By preferentially adsorbing moisture to the gelled layer, it is possible to prevent the electrolyte and solute components contained in the fluid (droplet) of the specimen or reagent from being directly adsorbed to the hydrophobic substrate 21A. it can.

Further, according to the present embodiment, as described above, the support substrate 21 is the hydrophobic substrate 21A, and the support substrate 21 itself has hydrophobicity (water repellency). The step of hydrophobizing (the surface facing the outside of the cell) becomes unnecessary. This simplifies the entire process.

Further, as described above, in this embodiment, the molded hydrophobic substrate 21A has the through-hole 25 from the beginning by forming the through-hole 25 at the time of molding the support substrate 21 by injection molding. . For this reason, according to this embodiment, by using the hydrophobic substrate 21 A as the support substrate 21, it is not necessary to form the through hole 25 later. Therefore, the hole making process (through hole forming process) is unnecessary, and the number of processes can be reduced correspondingly.

However, the present embodiment is not limited to this, and the electrowetting device 1 having the structure shown in FIG. 9 is formed by forming the through hole 25 in the plate-like support substrate 21 made of a hydrophobic base material. Needless to say, it may be manufactured.

[Embodiment 4]
This embodiment will be described below with reference to FIG. In the present embodiment, differences from the third embodiment will be described. Components having the same functions as those used in the third embodiment are denoted by the same reference numerals, and description thereof is omitted. .

<Schematic configuration of electrowetting device 1>
FIG. 14 is an enlarged cross-sectional view showing the configuration in the vicinity of the fluid injection hole of the electrowetting device 1 according to the present embodiment.

As shown in FIG. 14, the electrowetting device 1 according to the present embodiment is not limited to the opening wall 25a of the through-hole 25 but also from the through-hole 25a to the lower substrate, similarly to the electrowetting device 1 according to the second embodiment. 10 is the same as the electrowetting device 1 according to the third embodiment except that the region connected to the facing surface (lower surface) 10 is a hydrophilic surface.

That is, as shown in FIG. 14, the electrowetting device 1 according to the present embodiment includes an electrode of the upper substrate 20 located in the through hole 25 of the upper substrate 20 and the lower surface of the upper substrate 20 (that is, in the cell). The hydrophilic layer 24 having a surface tension higher than that of the

hydrophobic layers

15 and 23 is formed in a certain region around the through-hole 25 in the surface 22).

In the electrowetting device 1 according to the present embodiment, like the electrowetting device 1 according to the third embodiment, the support substrate 21 is a hydrophobic substrate 21A made of a hydrophobic base material, and has a hydrophobic surface. The hydrophobic substrate 21 A itself is a hydrophobic layer on the upper surface of the upper substrate 20.

For this reason, the hydrophobic layer 23 is not provided on the upper surface of the support substrate 21, and the hydrophobic layer 23 is a region other than the region where the hydrophilic layer 24 is formed on the lower surface of the upper substrate 20. It is formed in the contact area.

Also in the present embodiment, as in the second embodiment, the formation region of the hydrophilic layer 24 around the through hole 25 on the lower surface of the upper substrate 20 is a concentric area centering on the through hole 25 in plan view. A surface region facing the lower substrate 10 having a diameter (g3) larger by a predetermined amount than the opening diameter (g2, diameter) of the mouth 25 is a hydrophilic surface.

The upper substrate 20 in the electrowetting device 1 according to the present embodiment can be easily manufactured by combining, for example, the methods described in the second and third embodiments. For this reason, in this embodiment, illustration of a manufacturing process is abbreviate | omitted.

Hereinafter, an example of a method for manufacturing the upper substrate 20 will be described.

First, as the hydrophobic substrate 21A provided with the electrodes 22, for example, a glass substrate having a thickness of 0.7 mm having a predetermined size in which an ITO film is provided in a solid form on the entire main surface is used as shown in FIG. In the same manner as the steps shown in a) to (c), a resist is formed on a concentric region having a diameter g3 centering on a region where the through hole 25 is to be formed on the surface on which the electrode 22 is formed in the hydrophobic substrate 21A. A pattern 71a is formed.

Subsequently, for example, similarly to the step shown in FIG. 13 (f), a 1 wt% diluted solution of “CYTOP (registered trademark) -CTL809A” manufactured by AGC Asahi Glass Co., Ltd., which is a perfluoroamorphous resin as a hydrophobic treatment agent, is used. The hydrophobic treatment agent is coated on the surface of the hydrophobic substrate 21A on which the electrode 22 is formed by a slit coater, so that the hydrophobic layer 23 (cytotop, for example, having a thickness of 50 nm is formed on the resist pattern 71a and the electrode 22. Film).

Thereafter, the resist pattern 71a and the hydrophobic layer 23 on the resist pattern 71a are removed in the same manner as in the second embodiment. Specifically, for example, the hydrophobic layer 23 is formed in “SPX” (trade name, 2-aminoethanol) manufactured by Hayashi Junyaku Kogyo Co., Ltd. in the same manner as in the step shown in FIG. The support substrate 21 is immersed, and ultrasonic waves are applied for 5 minutes at room temperature, whereby the resist pattern 71a and the hydrophobic layer 23 on the resist pattern 71a are peeled off. As a result, the region where the through hole 25 is to be formed on the lower surface of the hydrophobic substrate 21A and the surface of the electrode 22 around it are partially exposed.

Thereafter, the through hole 25 having a predetermined opening diameter g2 is formed on the hydrophobic substrate 21A using, for example, a precision drill or a laser drill dedicated to glass.

Subsequently, as in the step shown in FIG. 13C, for example, “BIOSURFINE (registered trademark) -AWP” (manufactured by Toyo Gosei Co., Ltd.), which is a water-soluble photosensitive resin-coated hydrophilic coating material. By immersing the hydrophobic substrate 21A in an aqueous solution and dip-coating the whole, the hydrophilic layer 24 is formed on the entire surface of the hydrophobic substrate 21A including the inside of the through hole 25.

Next, in the step shown in FIG. 13D, a photomask that shields the region where the hydrophobic layer 23 is formed on the lower surface of the hydrophobic substrate 21A is used as the photomask 72. The hydrophobic substrate 21A is masked, and ultraviolet rays are irradiated from the surface of the hydrophobic substrate 21A on which the electrode 22 is formed to the through hole 25 and a concentric area having a diameter g3 with the through hole 25 as the center. As a result, the hydrophilic coating material (hydrophilic layer 24) in the concentric region having a diameter g3 centered on the through hole 25 and in the through hole 25 is gelled.

Thereafter, similarly to the step shown in FIG. 13 (e), the hydrophobic substrate 21A is washed with water, and the non-gelled coating portion (hydrophilic layer 24) is dissolved and peeled off. As a result, the gel-like hydrophilic layer 24 remains only in the concentric region having a diameter g3 with the through-hole 25 and the through-hole 25 on the surface where the electrode 22 is formed in the hydrophobic substrate 21A as the center.

According to the present embodiment, as described above, since the hydrophilic layer 24 is formed around the through hole 25 on the lower surface of the upper substrate 20, the same effect as in the second embodiment can be obtained.

Further, according to the above process, the hydrophilic layer 24 made of a gelling layer of a hydrophilic coating material is formed in a concentric region having a diameter g3 around the through hole 25 and the through hole 25 on the lower surface of the upper substrate 20. By being formed, the same effect as in the third embodiment can be obtained.

Further, according to the present embodiment, the support substrate 21 is the hydrophobic substrate 21A, and the support substrate 21 itself has hydrophobicity (water repellency), so that the upper surface of the upper substrate 20 (on the outside of the cell). The process of hydrophobizing the facing surface) becomes unnecessary. For this reason, compared with Example 2, for example, a process can be simplified.

[Embodiment 5]
The present embodiment will be described below with reference to FIGS. 15 and 16. In the present embodiment, differences from the first embodiment will be described, and components having the same functions as those used in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted. .

<Schematic configuration of electrowetting device 1>
FIG. 15 is an enlarged cross-sectional view showing a configuration near the fluid injection hole of the electrowetting device 1 according to the present embodiment.

As shown in FIG. 15, the electrowetting device 1 according to the present embodiment has the same configuration as the electrowetting device 1 according to the first embodiment except that the upper substrate 20 has the following configuration. have.

In the present embodiment, instead of forming the hydrophobic layer 23 on the upper surface of the support substrate 21 by subjecting the upper surface of the upper substrate 20 to hydrophobic treatment, the upper substrate made of a hydrophobic base material is formed on the support substrate 21. 26 is provided.

That is, the upper substrate 20 according to the present embodiment has an electrode 22 on the lower surface side of the support substrate 21 and a hydrophobic layer 23 covering the electrode 22, and a hydrophobic layer on the surface on the upper surface side of the support substrate 21. The upper substrate 26 is made of a hydrophobic base material, and the hydrophilic layer 24 is provided on the surface of the support substrate 21 in the through hole 25.

Note that a hydrophilic layer 24 is formed between the upper surface of the support substrate 21 and the upper substrate 26 and on the side surfaces of the support substrate 21 by performing hydrophilic treatment on the support substrate 21 as shown in FIG. May be.

In the present embodiment, since the upper substrate 20 includes the upper surface substrate 26 as described above, the through hole 25 is provided so as to penetrate the upper substrate 20 provided with the upper surface substrate 26 in the vertical direction. Yes. Therefore, the upper surface substrate 26 is provided with a through hole 25 A that is a part of the through hole 25 as the through hole 25.

The opening wall 26a of the upper surface substrate 26 in the through hole 25 is formed to be inclined so as to have an inversely tapered shape in which the opening diameter becomes smaller toward the support substrate 21 side.

That is, as in the first embodiment, when the opening diameter (diameter) of the support substrate 21 is g2, the opening diameter (diameter) at the lower end of the upper substrate 26 is g2, and the opening diameter (diameter) at the upper end of the upper substrate 26 is It is formed larger than g2. In addition, in FIG. 15, since each layer is emphasized and shown similarly to other embodiment, the hydrophilic layer 24 is protruded from the other layers, but the hydrophilic layer 24 is a hydrophilic treatment agent. The end surface of each layer is formed to be substantially flush with each other.

The opening wall 26a of the upper surface substrate 26 in the through hole 25 has a gradient of the opening wall 26a (an angle formed between the opening wall 26a and the normal direction of the upper surface substrate 26) as θ ′, and the droplet 40 with respect to the opening wall 26a. The contact angle (contact angle at 20 ° C.) is preferably θ ′ = θ−90 degrees. Since the opening wall 26a has the inversely tapered shape as described above, the droplet 40 can be easily injected into the through-hole 25. In addition, since the opening wall 26a has the gradient, a region surrounded by the hydrophilic layer 24 (hydrophilic layer) in the through-hole 25 can be obtained simply by dropping an appropriate amount of the droplet 40 into the through-hole 25. 24), the droplet 40 is likely to enter. For this reason, the droplet 40 injected from the through-hole 25 can be brought into more reliable contact with the surface of the lower substrate 10 (that is, the surface of the dielectric layer 14 covered with the hydrophobic layer 23).

As the hydrophobic base material used for the upper substrate 26, a base material similar to the hydrophobic base material used for the hydrophobic substrate 21A in the third embodiment can be used.

Similarly to the hydrophobic substrate 21A, the top substrate 26 is also preferably a hydrophobic substrate having a contact angle θ of the droplet 40 of 80 degrees or more, more preferably 90 degrees or more. Examples of such a hydrophobic substrate include: Further, a hydrophobic substrate having a water contact angle θ of 80 degrees or more, more preferably 90 degrees or more can be mentioned.

By using a perforated substrate made of resin (plastic) formed by injection molding for the upper surface substrate 26, it is not necessary to separately form a through-hole 25 later on the upper surface substrate 26, like the hydrophobic substrate 21A. The process can be simplified.

FIGS. 16A to 16F are views showing an example of the manufacturing process of the upper substrate 20 in the electrowetting apparatus 1 according to the present embodiment in the order of processes.

First, as shown in FIG. 16A, as the support substrate 21 provided with the electrodes 22, for example, an ITO film is provided in a solid shape on the entire surface of one main surface and has a predetermined size of 0.7 mm in thickness. Prepare a glass substrate.

Next, on the surface of the support substrate 21 where the electrode 22 is formed (that is, the electrode surface that is the inner surface of the cell), as a hydrophobic treatment agent, for example, “Cytop (registered) manufactured by AGC Asahi Glass Co., Ltd., which is a perfluoroamorphous resin. A 1 wt% diluted solution of “trademark) -CTL809A” is spin-coated at, for example, a rotation speed of 3000 rpm for 20 seconds. Thereby, as shown in FIG. 16B, a hydrophobic layer 23 (Cytop film) having a thickness of 50 nm, for example, is formed on the electrode surface.

After that, as shown in FIG. 16C, a predetermined position of the support substrate 21 on which the hydrophobic layer 23 is formed is finally formed into a part of the through hole 25 of the upper substrate 20 by, for example, a laser drill. A predetermined size (opening diameter g2) and a predetermined number of through holes 25A are formed.

Next, the support substrate 21 in which the through hole 25 is formed is immersed in, for example, a hydrophilic treatment agent. In the present embodiment, for example, a betaine group-containing hydrophilic polymer having a terminal silanol group (“LAMBIC-500WP”, trade name) manufactured by Osaka Organic Chemical Industry Co., Ltd.) is used as the hydrophilic treatment agent so as to have a predetermined viscosity. A hydrophilic polymer aqueous solution diluted with water was used, and the support substrate 21 having the through-holes 25A formed therein was immersed in the hydrophilic polymer aqueous solution.

Hydrophilic treatment agent is not coated on the hydrophobic surface. For this reason, only the area | region in which the hydrophobic layer 23 is not formed in the said support substrate 21 is hydrophilic-coated by performing the said process. Therefore, by performing the above processing, as shown in FIG. 16D, a hydrophilic layer 24 is formed in a region of the support substrate 21 excluding the region where the hydrophobic layer 23 is formed.

On the other hand, apart from the steps shown in FIGS. 16A to 16D, as shown in FIG. 16E, as the upper surface substrate 26, a predetermined size and a predetermined number of penetrations are formed at predetermined positions by injection molding. An upper substrate 26 made of resin (plastic) provided with the opening 25B is formed.

Here, the predetermined position indicates a position where the through hole 25A and the through hole 25B overlap when the upper surface substrate 26 and the support substrate 21 are bonded together. The predetermined number indicates a number that matches the number of the through holes 25A. In addition, the predetermined size means that the opening diameter of the opening end on the one surface (surface to be bonded to the support substrate 21) side of the upper substrate 26 is bonded to the upper substrate 26 as shown in FIG. The size substantially coincides with the opening diameter of the substrate 21.

In this embodiment, as the upper surface substrate 26, a perforated substrate having an inversely tapered opening wall 26a made of polypropylene resin having a low surface tension of the material itself is formed. The gradient θ ′ of the opening wall 26a was a contact angle θ-90 degrees.

Thereafter, as shown in FIG. 16F, the support substrate 21 formed with the hydrophilic layer 24 shown in FIG. 16D and the top substrate 26 shown in FIG. Bonding is performed with a predetermined adhesive so that the central axes of the opening 25A and the through-hole 25B coincide with each other (the opening wall 25a of the through-hole 25A and the opening wall 26a of the through-hole 25B are flush with each other). Thereby, the upper substrate 20 provided with the through hole 25 including the through hole 25A and the through hole 25B communicating with each other is completed.

According to the present embodiment, as described above, the upper surface of the support substrate 21 may be a hydrophilic surface (for example, the hydrophilic layer 24). Therefore, in the present embodiment, a mask (photo) required to form a hydrophilic surface in the through-hole 25 while making the contact region with the droplet 40 around the through-hole 25 on the upper surface of the upper substrate 20 a hydrophobic surface. No mask processing using a mask or a resist pattern is required, and the process is further simplified as compared with Examples 1 and 3, for example, in which the hydrophilic layer 24 is not provided on the lower surface of the upper substrate 20 as in the present embodiment. be able to.

[Embodiment 6]
The present embodiment will be described below with reference to FIG. Note that in this embodiment, differences from the fifth embodiment will be described, and components having the same functions as the components used in the fifth embodiment will be denoted by the same reference numerals, and description thereof will be omitted. .

<Schematic configuration of electrowetting device 1>
FIG. 17 is an enlarged cross-sectional view showing the configuration in the vicinity of the fluid injection hole of the electrowetting device 1 according to the present embodiment.

As shown in FIG. 17, the electrowetting device 1 according to the present embodiment is not limited to the opening wall 25 a of the through-hole 25, but also from the through-hole 25 a to the lower substrate, similarly to the electrowetting device 1 according to the second embodiment. 10 is the same as the electrowetting device 1 according to the fifth embodiment except that the region connected to the facing surface (lower surface) 10 is a hydrophilic surface.

In the present embodiment, as in the second embodiment, the formation region of the hydrophilic layer 24 around the through hole 25 on the lower surface of the upper substrate 20 is a concentric area centering on the through hole 25 in plan view. A surface region facing the lower substrate 10 having a diameter (g3) larger than the opening diameter (g2, diameter) of the through hole 25 by a predetermined amount is a hydrophilic surface.

The upper substrate 20 in the electrowetting device 1 according to the present embodiment can be easily manufactured by combining the methods described in the above-described embodiments including the second embodiment and the fifth embodiment, for example. For this reason, in this embodiment, illustration of a manufacturing process is abbreviate | omitted.

Thereafter, in the same manner as the steps shown in FIGS. 10A to 10C, a concentric circle having a diameter g3 centering on a region where the through hole 25 is to be formed on the surface of the support substrate 21 where the electrode 22 is to be formed. In this region, a resist pattern 71a is formed.

Subsequently, for example, similarly to the step shown in FIG. 13 (f), a 1 wt% diluted solution of “CYTOP (registered trademark) -CTL809A” manufactured by AGC Asahi Glass Co., Ltd., which is a perfluoroamorphous resin as a hydrophobic treatment agent, is used. The hydrophobic treatment agent is used to coat the surface of the support substrate 21 on which the electrode 22 is formed with a slit coater, so that the hydrophobic layer 23 (cytop film, for example, having a thickness of 50 nm is formed on the resist pattern 71a and the electrode 22. ).

Thereafter, the resist pattern 71a and the hydrophobic layer 23 on the resist pattern 71a are removed in the same manner as in the second embodiment. Specifically, for example, the hydrophobic layer 23 is formed in “SPX” (trade name, 2-aminoethanol) manufactured by Hayashi Junyaku Kogyo Co., Ltd. in the same manner as in the step shown in FIG. The support substrate 21 is immersed, and ultrasonic waves are applied for 5 minutes at room temperature, whereby the resist pattern 71a and the hydrophobic layer 23 on the resist pattern 71a are peeled off. Thereby, the surface of the electrode 22 in the region where the through hole 25 is to be formed on the lower surface of the support substrate 21 and the diameter g3 centering on the region where the through hole 25 is to be formed is partially exposed.

Thereafter, the through hole 25 having a predetermined opening diameter g2 is formed on the support substrate 21 using a precision drill or a laser drill dedicated to glass.

As a result, similarly to the step shown in FIG. 16C, a predetermined size (opening diameter g2), which becomes a part of the through hole 25 of the upper substrate 20 at a predetermined position of the support substrate 21, is predetermined. A number of through holes 25A are formed.

Next, similarly to the step shown in FIG. 16D, the support substrate 21 in which the through-hole 25A is formed is, for example, a betaine group-containing hydrophilic polymer having a terminal silanol group (manufactured by Osaka Organic Chemical Industries, Ltd. LAMBIC-500WP "(trade name) is immersed in a hydrophilic treatment agent comprising a hydrophilic polymer aqueous solution diluted with water so as to have a predetermined viscosity, thereby removing the formation region of the hydrophobic layer 23 on the support substrate 21. A hydrophilic layer 24 is formed in the region.

On the other hand, as in the step shown in FIG. 16 (e), as the upper surface substrate 26, a resin (plastic) upper surface substrate in which a predetermined size and a predetermined number of through holes 25B are provided at predetermined positions by injection molding. 26 is formed.

In the present embodiment, the predetermined position refers to a position where the through hole 25A and the through hole 25B overlap when the upper surface substrate 26 and the support substrate 21 are bonded together. The predetermined number indicates a number that matches the number of the through holes 25A. Further, the predetermined size means that the opening diameter of the opening end on the one surface (surface to be bonded to the support substrate 21) side of the upper surface substrate 26 substantially matches the opening diameter of the support substrate 21 to be bonded to the upper surface substrate 26. Indicates the size.

In the present embodiment, as in the fifth embodiment, a perforated substrate having an inversely tapered opening wall 26a made of, for example, polypropylene resin whose surface tension is low is formed as the upper substrate 26. The gradient θ ′ of the opening wall 26a was a contact angle θ-90 degrees.

Thereafter, similarly to the step shown in FIG. 16F, the central axes of the through hole 25A and the through hole 25B of the support substrate 21 on which the hydrophilic layer 24 is formed and the upper surface substrate 26 coincide with each other ( Bonding is performed with a predetermined adhesive so that the opening wall 25a of the through hole 25A and the opening wall 26a of the through hole 25B are flush with each other. Thereby, the upper substrate 20 according to the present embodiment is completed.

Further, according to the present embodiment, as described above, the upper surface of the support substrate 21 may be a hydrophilic surface (for example, the hydrophilic layer 24). Therefore, in this embodiment as well as in the fifth embodiment, the contact area of the upper surface of the upper substrate 20 with the droplets 40 around the through-hole 25 is a hydrophobic surface and a hydrophilic surface is formed in the through-hole 25. This eliminates the need for the necessary mask. For this reason, compared with Example 2, for example, a process can be simplified.

[Summary]
The electrowetting device 1 according to the first aspect of the present invention includes a lower substrate 10 having a first electrode (electrode 13) and an upper substrate 20 having a second electrode (electrode 22) that are bonded to each other with a gap. The upper substrate 20 has an injection port (through port 25) for injecting the droplet 40 into the gap, and the first electrode is provided in a region including a region immediately below the injection port. A hydrophobic layer (for example, a hydrophobic layer 15, a hydrophobic layer 23, a hydrophobic layer) is formed in a region where the droplet 40 contacts on the upper surface of the upper substrate 20 and a region where the droplet 40 contacts on the lower substrate 10. 21A and a top substrate 26), and a hydrophilic layer 24 having a surface tension higher than that of the hydrophobic layer is provided in the injection port.

According to the above configuration, the droplet 40 dropped on the injection port naturally has a volume of the hydrophilic region (for example, the injection port) in the hydrophilic region (that is, the formation region of the hydrophilic layer 24) in the injection port. When all the opening walls are hydrophilic layers, a certain amount of liquid is stored according to the volume of the injection port.

For this reason, according to the above configuration, the droplet 40 is naturally fixed in the gap (microchannel) by simply dropping an appropriate amount of the droplet 40 to the injection port provided in the upper substrate 20. The amount is sucked.

For this reason, it is only necessary to drop or continuously flow the droplet 40 from above the inlet, and no complicated fluid (droplet) injection mechanism is required.

Therefore, according to the above configuration, the electrowetting capable of injecting the droplet 40 into the gap (that is, the electrowetting device 1) without requiring a complicated fluid (droplet) injection mechanism. 1 can be provided.

In the electrowetting device 1 according to aspect 2 of the present invention, in the aspect 1, the distance (g1) between the lower substrate 10 and the upper substrate 20 is larger than the opening diameter (g2) of the injection port. It is desirable.

According to the above configuration, the droplet 40 injected from the injection port can be reliably brought into contact with the surface of the lower substrate 10 in the gap and drawn into the gap by electrowetting phenomenon.

Aspect 3 of the present invention is the electrowetting device 1 according to the

aspect

1 or 2, wherein the upper substrate 20 has a support substrate 21 that supports the second electrode, and the liquid on the upper surface of the support substrate 21 It is desirable that the hydrophobic layer (for example, the hydrophobic layer 23, the upper surface substrate 26) is provided in a region where the droplet 40 contacts, and the hydrophilic layer 24 is provided on the surface of the support substrate 21 in the inlet. .

According to the above configuration, the effect described in the first aspect can be obtained.

The electrowetting device 1 according to aspect 4 of the present invention is the electrowetting device 1 according to aspect 3, wherein the hydrophobic layer on the upper surface of the upper substrate 20 is provided on the support substrate 21 and made of a hydrophobic base material. It is desirable that

According to the above configuration, the contact area of the upper surface of the upper substrate 20 with the droplets 40 around the injection port is a hydrophobic surface, and a mask necessary for forming a hydrophilic surface in the injection port is unnecessary. Yes, the process can be simplified.

In the electrowetting device 1 according to the aspect 5 of the present invention, in the aspect 4, the opening wall 26a of the upper surface substrate 26 in the injection port has an inversely tapered shape whose opening diameter becomes smaller toward the support substrate 21 side. It is desirable that

According to the above configuration, the droplet 40 can be easily injected into the injection port.

In the electrowetting device 1 according to the sixth aspect of the present invention, in the fifth aspect, the contact angle of the droplet 40 with respect to the upper surface substrate 26 is θ, and the gradient of the opening wall 26a of the upper surface substrate 26 at the inlet is as follows. Assuming that θ ′, θ ′ = θ−90 degrees is desirable.

According to the above configuration, the droplet 40 can easily enter the formation region of the hydrophilic layer 24 in the injection port simply by dropping a suitable amount of the droplet 40 in the injection port. For this reason, the droplet 40 injected from the injection port can be brought into more reliable contact with the surface of the lower substrate 10 in the gap and drawn into the gap by electrowetting phenomenon.

The electrowetting device 1 according to aspect 7 of the present invention is the electrowetting device 1 according to

aspect

1 or 2, wherein the upper substrate 20 is a support substrate (hydrophobic substrate 21A) made of a hydrophobic base material that supports the second electrode. Preferably, the hydrophobic layer on the upper surface of the upper substrate 20 is the support substrate, and the hydrophilic layer 24 is preferably provided on the surface of the support substrate in the inlet.

According to the above configuration, the step of hydrophobizing the upper surface of the upper substrate 20 is not necessary. This simplifies the entire process.

In the electrowetting device 1 according to the eighth aspect of the present invention, in any of the fourth to seventh aspects, the hydrophobic substrate is preferably a plastic substrate.

According to the above configuration, the hydrophobic base material can be injection-molded, and it is not necessary to separately form the injection port, so that the number of steps can be reduced.

In the electrowetting device 1 according to the ninth aspect of the present invention, the surface tension of the electrowetting device 1 according to any one of the first to eighth aspects is higher than that of the hydrophobic layer 23 in a certain region around the injection port on the lower surface of the upper substrate 20. It is desirable that the high hydrophilic layer 24 is formed, and the hydrophobic layer 23 is formed in a region where the droplet 40 contacts in a region other than the region where the hydrophilic layer 24 is formed on the lower surface of the upper substrate 20.

According to the above configuration, more droplets 40 dropped into the injection port are drawn into the gap, and are reliably grounded (contacted) with the surface of the lower substrate 10 in the gap. The contact area with respect to each of the upper substrate 20 and the lower substrate 10 increases.

Therefore, according to the above configuration, it is possible to further suppress the occurrence of a problem that the droplet 40 injected into the injection port does not enter the gap.

A liquid droplet injection method according to aspect 10 of the present invention is a liquid droplet injection method for injecting liquid droplets 40 into the electrowetting device 1 according to any one of aspects 1 to 9, wherein a liquid is injected into the injection port. In the state where the droplet 40 is dropped and the droplet 40 dropped on the inlet is in contact with the lower substrate 10, a voltage is applied to the first electrode and the second electrode to move the droplet 40. In this way, the droplet 40 is drawn into the gap.

According to the above method, the same effect as in the first aspect can be obtained. Therefore, according to the above configuration, a droplet that can inject the droplet 40 into the gap (that is, the electrowetting device 1) without requiring a complicated fluid (droplet) injection mechanism. An injection method can be provided.

In the manufacturing method of the electrowetting device 1 according to the aspect 11 of the present invention, the lower substrate forming step for forming the lower substrate 10 on which the first electrode (electrode 13) is formed, and the second electrode (electrode 22) are formed. An upper substrate forming step for forming the upper substrate 20; and a bonding step for bonding the upper substrate 20 and the lower substrate 10 with a gap between each other. A step of forming an injection port (through port 25) for injecting the droplet 40 into the surface, and a hydrophobic layer (for example, a hydrophobic layer 23, a hydrophobic layer in a region of the upper surface of the upper substrate 20 that contacts the droplet 40; The upper substrate hydrophobic layer forming step for forming the conductive substrate 21A and the upper substrate 26), and the hydrophilic layer forming step for forming the hydrophilic layer 24 having a surface tension higher than that of the hydrophobic layer in the inlet. Base The forming step includes a step of forming the first electrode in a region including a region immediately below the injection port, and a step of forming a lower substrate hydrophobic layer in which the hydrophobic layer 15 is formed in a region in contact with the droplet 40. It is the method of including.

According to the above method, the same effect as in the first aspect can be obtained. Therefore, according to the above configuration, the electrowetting capable of injecting the droplet 40 into the gap (that is, the electrowetting device 1) without requiring a complicated fluid (droplet) injection mechanism. A manufacturing method of the marking device 1 can be provided.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

DESCRIPTION OF SYMBOLS 1 Electrowetting apparatus 2 Active area | region 3 Frame area | region 10 Lower board |

substrate

11, 21 Support board | substrate 12 Thin film

electronic circuit

13, 13a, 13b, 22 Electrode 14

Dielectric layer

15, 23 Hydrophobic layer 16 Electrode array 17 Array element circuit 20 Upper board | substrate 21A Hydrophobic substrate 24 Hydrophilic layers 25, 25A, 25B, 60a Through-hole (injection port)
25a, 26a Opening wall 26 Upper surface substrate 30 Flow path 31 Sealing material 32

Spacer

40, 40a, 40b, 40c, 41 Droplet 42 Non-conductive liquid 51 Row drive circuit 52 Column drive circuit 53 Serial interface 54 Voltage supply interface 55

Connection wire

60, 60A Adhesive body 61 Mother substrate 61A Chip 61a Through-hole formation planned

area

61b, 61c Area 62 Temporary fixing adhesive 63 Protective sheet 64 Container 65 Resist liquid 65A, 71 Resist layer 71a Resist pattern 72 Photomask

Claims

A lower substrate having a first electrode and an upper substrate having a second electrode, which are bonded to each other with a gap;
The upper substrate has an inlet for injecting droplets into the gap,
The first electrode is provided in a region including a region directly below the injection port,
A hydrophobic layer is provided in each of the upper surface of the upper substrate in a region where the droplet contacts and a region in the lower substrate where the droplet contacts,
An electrowetting device, wherein a hydrophilic layer having a surface tension higher than that of the hydrophobic layer is provided in the injection port.
The electrowetting device according to claim 1, wherein a distance between the lower substrate and the upper substrate is larger than an opening diameter of the injection port.
The upper substrate has a support substrate that supports the second electrode,
The hydrophobic layer is provided on the upper surface of the support substrate in a region where the droplet contacts,
The electrowetting device according to claim 1 or 2, wherein the hydrophilic layer is provided on a surface of the support substrate in the injection port.
The electrowetting device according to claim 3, wherein the hydrophobic layer on the upper surface of the upper substrate is an upper substrate made of a hydrophobic base material provided on the support substrate.
5. The electrowetting device according to claim 4, wherein the opening wall of the upper surface substrate at the inlet has an inversely tapered shape in which the opening diameter decreases toward the support substrate.
6. The relationship according to claim 5, wherein θ ′ = θ−90 degrees, where θ is a contact angle of the droplet with respect to the upper surface substrate, and θ ′ is a gradient of the opening wall of the upper surface substrate at the inlet. The electrowetting device described.
The upper substrate has a support substrate made of a hydrophobic base material that supports the second electrode,
The hydrophobic layer on the upper surface of the upper substrate is the support substrate,
The electrowetting device according to claim 1 or 2, wherein the hydrophilic layer is provided on a surface of the support substrate in the injection port.
The electrowetting device according to any one of claims 4 to 7, wherein the hydrophobic substrate is a plastic substrate.
A hydrophilic layer having a surface tension higher than that of the hydrophobic layer is formed in a certain region around the inlet on the lower surface of the upper substrate, and the region other than the region where the hydrophilic layer is formed on the lower surface of the upper substrate. The electrowetting device according to any one of claims 1 to 8, wherein a hydrophobic layer is formed in a region where the droplet contacts.
A droplet injection method for injecting droplets into the electrowetting device according to any one of claims 1 to 9,
Dropping droplets into the inlet;
In the state where the liquid droplet dropped on the injection port is in contact with the lower substrate, a voltage is applied to the first electrode and the second electrode to move the liquid droplet, thereby bringing the liquid droplet into the gap. A method of injecting a droplet, which is drawn.
A lower substrate forming step of forming a lower substrate on which the first electrode is formed;
An upper substrate forming step of forming an upper substrate on which the second electrode is formed;
A bonding step in which the upper substrate and the lower substrate are bonded together with a gap therebetween,
The upper substrate forming step includes
An inlet forming step for forming an inlet for injecting droplets into the gap;
An upper substrate hydrophobic layer forming step of forming a hydrophobic layer in a region where the droplet contacts on the upper surface of the upper substrate;
Forming a hydrophilic layer having a higher surface tension than the hydrophobic layer in the inlet, and a hydrophilic layer forming step,
The lower substrate forming step includes
Forming the first electrode in a region including a region directly below the inlet;
And a lower substrate hydrophobic layer forming step of forming a hydrophobic layer in a region where the droplet contacts.