Pattern electrode structure for electro-wetting apparatus

Abstract

The present invention relates to a pattern electrode structure for an electro-wetting device that is laminated between a base material and a dielectric layer, comprising a plurality of branch electrodes formed along a perpendicular direction to any plane perpendicular to the plane formed by the pattern electrode structure and spaced apart at regular intervals, and a plurality of sub-branch electrodes formed extending a certain length in an inclined direction from each of the plurality of branch electrodes. According to the present invention, self-cleaning performance can be more efficiently exhibited even with small droplets.

Description

Technology Field

[0001] The present invention relates to an electrode structure having a pattern structure utilizing an electro-wetting technology phenomenon. Background Technology

[0002] The electro-wetting phenomenon refers to the phenomenon of "change in the contact angle between a solid and an electrolyte due to the potential difference between the solid and the electrolyte."

[0003] By utilizing this phenomenon, the surface tension of a droplet placed on an electrode coated with an insulator can be controlled, thereby enabling the control of deformation / movement of microfluids in units of microliters (µL) or smaller.

[0004] In addition, since no separate external drive unit is required for operation, the lightweight design of application products is possible. Furthermore, because the insulator coated on the electrodes restricts current flow, power consumption is low and response speed is fast, attracting significant interest in various industrial fields.

[0005] Examples of industrial applications of electrowetting include lab-on-a-chip devices, fluid lenses, and displays, which are next-generation electronic devices utilizing methods different from conventional ones.

[0006] In addition, since it is possible to move, deform, or remove droplets formed on glass using an electro-wetting device, it is possible to remove rainwater, dew, etc. by mounting it on vehicle windshields, side mirrors, cameras, etc.

[0007] The present invention is a self-cleaning technology utilizing the electrowetting phenomenon.

[0008] The 'electrowetting self-cleaning device' has a structure and function capable of periodically / repeatedly applying direct current or alternating current to the surface of a substrate.

[0009] When a 'polar fluid drop (sessile drop)' is placed on the surface of an 'electrowetting self-cleaning device', the 'polar fluid drop' can receive attractive and repulsive forces due to the electric field formed on the surface of the substrate.

[0010] Therefore, when the applied voltage is direct current, the 'polar fluid droplet' can be drawn along the direction of the electric field, and when the applied voltage is alternating current, the 'polar fluid droplet' can oscillate due to changes in the periodic electric field.

[0011] The present invention is a method of generating vibrations of a 'polar fluid droplet' using alternating current, and is a technology that causes a droplet to fall by reducing the fixing force of the fluid droplet located on the surface of a device.

[0012] That is, before voltage is applied (when the fluid droplet adheres to the surface), the force relationship is gravity = fixing force (friction + viscosity + reaction force due to contact angle hysteresis), and after voltage is applied (when the fluid droplet begins to slide), gravity > fixing force (friction + viscosity + reaction force due to contact angle hysteresis↓), so the fluid droplet is dropped.

[0013] Here, Contact Angle Hysteresis (CAH) refers to a phenomenon in which the contact angle falls within a specific range due to solid surface heterogeneity or external factors.

[0014] FIG. 1 is a basic electrowetting self-cleaning device, wherein an electrode layer (10), a dielectric layer (30), and a water-repellent layer (40) are laminated on a base material glass (20).

[0015] The base material (20) is not limited to any specific type, but transparent glass may be used to mount it on a product that transmits visible light, such as a camera.

[0016] The electrode layer (10) should be located at the bottom of the dielectric layer as a transparent electrode pattern layer, and the higher the electrical conductivity, the more advantageous it is for performance.

[0017] Although it is not strictly necessary to be transparent, transparent electrodes must be used for mounting on products that transmit visible light. Representative materials include oxide-based ITO, polymer-based PEDOT:PSS, and oxide-polymer composite FTO.

[0018] The dielectric layer (30) can improve performance as it has a high dielectric constant and a thin thickness, and its durability and lifespan are improved as it has high dielectric breakdown strength and fewer defects. The more uniform, homogeneous, and continuous it is, the smaller the variation in performance and durability.

[0019] The dielectric layer (30) can be composed of a single layer or a multi-layer, and representative materials include oxide / nitride systems such as SiO2 / TiO2 / Al2O3 / CeO2 / HfO2 / ZrO2 / ZnO / SiON / Si3N4 and polymer systems such as Parylene-C, COP, and PMMA. Deposition methods include wet methods (Spray, Spin-coating, Ink-jet, etc.) and dry methods (E-beam, Sputtering, CVD, etc.).

[0020] The water-repellent layer (40) is not an essential element and can be omitted if the outermost layer of the dielectric layer has a sufficiently high contact angle.

[0021] Fluorine compounds are used as representative materials, and coating is performed using methods such as E-beam spin coating.

[0022] If the size of the fluid droplet is equal to or smaller than the width of the electrode currently located, the electromagnetic force from the adjacent electrode is weakened, and the vibration may be weak or absent.

[0023] Therefore, as shown in the example of Fig. 2, the electrode (E) must be designed to match the target size of the fluid droplet (D) to be removed, and must have a certain amount of overlap (O) where the fluid droplet spans across adjacent electrodes.

[0024] As a device for self-cleaning utilizing this principle, there is Korean Patent Publication No. 10-2018-0045079, etc.

[0025] This prior art is a technology that enables droplets to fall easily along the direction of the electrodes by configuring the pattern so that the electrodes are parallel to the direction of gravity.

[0026] However, since droplets with small mass and low gravity are difficult to fall, there are limitations to self-cleaning for small droplets, and if the thickness of the electrode is increased for this purpose, there is a limitation in efficiency.

[0027] Even computationally, the above prior art makes it difficult to induce falling motion when the volume of the water droplet is 0.2 µL to 0.1 µL.

[0028] The matters described in the background technology above are intended to aid in understanding the background of the invention and may include matters that are not prior art already known to those skilled in the art to which this technology belongs. Prior art literature

[0029] Korean Patent Publication No. 10-2018-0045079 The problem to be solved

[0030] The present invention was devised to solve the aforementioned problems, and the purpose of the present invention is to provide a pattern electrode structure for an electrowetting device that can more efficiently exhibit self-cleaning performance even with small droplets. means of solving the problem

[0031] A pattern electrode structure for an electro-wetting device according to one aspect of the present invention is a pattern electrode structure laminated between a base material and a dielectric layer of an electro-wetting device, and comprises a plurality of branch electrodes formed at regular intervals along a perpendicular direction to any plane perpendicular to a plane formed by the pattern electrode structure, and a plurality of sub-branch electrodes formed extending a certain length in an inclined direction from each of the plurality of branch electrodes.

[0032] In addition, the sub-branch electrode extending from one of the plurality of branch electrodes is characterized by being formed at a certain distance from the sub-branch electrode extending from the adjacent branch electrode.

[0033] In addition, the plurality of sub-branch electrodes are characterized by being formed by branching out and extending from both sides of the branch electrode.

[0034] Here, the plurality of sub-branch electrodes branched to both sides of the branch electrode are characterized by being formed to be inclined in the same direction, either upward or downward.

[0035] Furthermore, based on the branch electrode, the height at which the plurality of sub-branch electrodes branching to one side of the branch electrode branches is different from the height at which the plurality of sub-branch electrodes branching to the other side of the branch electrode branches.

[0036] Alternatively, based on the branch electrode, the height at which a plurality of sub-branch electrodes branch out to one side of the branch electrode and the height at which a plurality of sub-branch electrodes branch out to the other side of the branch electrode are the same.

[0037] Meanwhile, among the plurality of sub-branch electrodes branched to both sides of the branch electrode, the inclination direction of the plurality of sub-branch electrodes branched to one side and the plurality of sub-branch electrodes branched to the other side is characterized in that they are different directions among the upward direction and the downward direction.

[0038] In addition, based on the branch electrode, the height at which the plurality of sub-branch electrodes branching to one side of the branch electrode are branched is different from the height at which the plurality of sub-branch electrodes branching to the other side of the branch electrode are branched.

[0039] Alternatively, based on the branch electrode, the height at which a plurality of sub-branch electrodes branch out to one side of the branch electrode and the height at which a plurality of sub-branch electrodes branch out to the other side of the branch electrode are the same.

[0040] In addition, the plurality of sub-branch electrodes are characterized by being formed by branching and extending only to one side of the branch electrode.

[0041] Next, according to another aspect of the present invention, a pattern electrode structure for an electro-wetting device is laminated between a base material and a dielectric layer of an electro-wetting device and comprises a first electrode portion and a second electrode portion, wherein the first electrode portion is formed along a perpendicular direction to any plane perpendicular to the plane formed by the pattern electrode structure and comprises a plurality of first branch electrodes formed at regular intervals and a plurality of first sub-branch electrodes formed by extending a certain length in an inclined direction from each of the plurality of branch electrodes, and the second electrode portion is formed along a perpendicular direction to any plane perpendicular to the plane formed by the pattern electrode structure and comprises a plurality of second branch electrodes formed at regular intervals and a plurality of second sub-branch electrodes formed by extending a certain length in an inclined direction from each of the plurality of branch electrodes.

[0042] In addition, the first branch electrode and the second branch electrode are formed by being alternately arranged in a horizontal direction, and the inclination direction of the first sub-branch electrode and the second sub-branch electrode, which are each branched in a direction facing the adjacent first branch electrode and the second branch electrode, is characterized in that they are different directions among the upward and downward directions.

[0043] In addition, the plurality of first sub-branch electrodes and the plurality of second sub-branch electrodes are characterized in that the second sub-branch electrodes are positioned between adjacent first sub-branch electrodes.

[0044] In addition, the plurality of first sub-branch electrodes are characterized by being formed by branching out and extending from both sides of the first branch electrode, and the plurality of second sub-branch electrodes are characterized by being formed by branching out and extending from both sides of the second branch electrode.

[0045] Furthermore, the plurality of first sub-branch electrodes branched to both sides of the first branch electrode are formed to be inclined in the same direction, either upward or downward, and the plurality of second sub-branch electrodes branched to both sides of the second branch electrode are formed to be inclined in the same direction, either upward or downward.

[0046] In addition, with respect to the first branch electrode, the height at which a plurality of first sub-branch electrodes branching to one side of the first branch electrode branches is different from the height at which a plurality of first sub-branch electrodes branching to the other side of the first branch electrode branches, and with respect to the second branch electrode, the height at which a plurality of second sub-branch electrodes branching to one side of the second branch electrode branches is different from the height at which a plurality of second sub-branch electrodes branching to the other side of the second branch electrode branches.

[0047] Alternatively, the slope direction of the plurality of first sub-branch electrodes branched to one side and the plurality of first sub-branch electrodes branched to the other side among the plurality of first sub-branch electrodes branched to both sides of the first branch electrode is characterized in that they are different from each other between the upward direction and the downward direction, and the slope direction of the plurality of second sub-branch electrodes branched to one side and the plurality of second sub-branch electrodes branched to the other side among the plurality of second sub-branch electrodes branched to both sides of the second branch electrode is characterized in that they are different from each other between the upward direction and the downward direction.

[0048] Alternatively, with respect to the first branch electrode, the height at which a plurality of first sub-branch electrodes branching to one side of the first branch electrode branches is different from the height at which a plurality of first sub-branch electrodes branching to the other side of the first branch electrode branches, and with respect to the second branch electrode, the height at which a plurality of second sub-branch electrodes branching to one side of the second branch electrode branches is different from the height at which a plurality of second sub-branch electrodes branching to the other side of the second branch electrode branches.

[0049] Meanwhile, the plurality of first sub-branch electrodes and the plurality of second sub-branch electrodes are each characterized by being formed by branching and extending only to one side of the first branch electrode and the second branch electrode. Effects of the invention

[0050] When operating the electrowetting device of the present invention, the phenomenon in which fluid droplets of a specific size (or volume) or smaller are not removed and adhere to the surface can be improved.

[0051] In addition, by adding additional sub-branch patterns to the existing branch patterns, the sliding direction of fluid droplets can be induced, and by merging the induced fluid droplets, a fluid droplet with large mass and volume can be created.

[0052] In addition, fluid droplets with increased mass and volume are subjected to stronger vibration and downward driving force by the electrowetting self-cleaning device, thereby improving cleaning performance.

[0053] This technology is particularly useful for applications where small water droplets occupy a large area of ​​the image, such as rearview cameras or SVM (Surround View Monitoring) cameras, and is effective in improving the accuracy of detection sensors caused by rainwater, contamination, etc. (Recognition of pedestrians, signs, vehicles, etc.) Brief explanation of the drawing

[0054] Figure 1 is a schematic representation of a basic electro-wetting device. Figure 2 compares the sizes of the droplet and the electrode. Figure 3 illustrates the concept of the pattern electrode structure of the present invention. FIG. 4 illustrates a pattern electrode structure for an electro-wetting device according to a first embodiment of the present invention. Figure 5 shows a scaled portion of Figure 4, and Figure 6 shows the movement of a droplet in the structure of Figure 5. FIG. 7 is an enlarged view of a part of a pattern electrode structure for an electro-wetting device according to a second embodiment of the present invention. FIGS. 8 and 9 show the movement state of a droplet in a pattern electrode structure for an electrowetting device according to a second embodiment of the present invention. FIG. 10 illustrates a pattern electrode structure for an electro-wetting device according to a third embodiment of the present invention. FIG. 11 illustrates an application example of a pattern electrode structure for an electrowetting device according to the first embodiment of the present invention. FIG. 12 illustrates a first application example of a pattern electrode structure for an electro-wetting device according to a second embodiment of the present invention. FIG. 13 illustrates a second application example of a pattern electrode structure for an electro-wetting device according to a second embodiment of the present invention. Specific details for implementing the invention

[0055] In order to fully understand the present invention, the operational advantages of the present invention, and the objectives achieved by the implementation of the present invention, reference must be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described in the accompanying drawings.

[0056] In describing preferred embodiments of the present invention, known technologies or repetitive descriptions that may unnecessarily obscure the essence of the invention will be shortened or omitted.

[0057] FIG. 3 illustrates the concept of a pattern electrode structure of the present invention, and FIG. 4 illustrates a pattern electrode structure for an electro-wetting device according to a first embodiment of the present invention.

[0058] Also, Fig. 5 shows a scaled portion of Fig. 4, and Fig. 6 shows the movement of a droplet in the structure of Fig. 5.

[0059] Hereinafter, a pattern electrode structure for an electrowetting device according to an embodiment of the present invention will be described with reference to FIGS. 3 to 6.

[0060] The present invention is a pattern electrode structure for an electrowetting device for increasing cleaning efficiency by increasing the falling speed of small droplets, and is a patterning technology that induces merging between droplets by controlling the movement direction of relatively small droplets (D1, D2) as shown in FIG. 3.

[0061] Therefore, the merging droplet (D) has a larger mass and volume than the original, and can more easily cause falling motion due to increased gravity.

[0062] As shown in the city, the electrode in the present invention has a specific angle between 0 and 90 degrees relative to the horizontal line, and has a structure in which a plurality of upper electrodes are gathered and integrated into one lower electrode.

[0063] The pattern is composed of an electrode portion for receiving an external applied voltage, a base electrode for transmitting the voltage received from the electrode portion, and branch electrodes that branch off from the electrostatic electrode and form an electric field by intersecting patterns having different polarities, which will be described in more detail later.

[0064] The droplets on the surface move along the length direction of the electrode pattern. In section A, the downward driving force is less than that of the vertical pattern by cos(90-θ), but when it reaches section B, the droplets merge, increasing mass and gravity, and thus the downward driving force is improved.

[0065] In other words, the descent speed in section A is lower than in section B, and the smaller the magnitude of θ, the greater the force received in the sliding direction.

[0066] In section B, as two droplets merge, the mass increases and the gravitational force increases. The radius of the droplets also increases, and the fixing force due to viscous force, frictional force, and contact angle hysteresis (CAH) increases slightly; however, since the value is small compared to the increased gravitational force caused by the modified counterattack, the downward driving force increases.

[0068] The pattern electrode structure according to the first embodiment of the present invention, referenced in FIGS. 4 and 5, has the Y-shaped pattern structure seen in FIG. 3 as its basic structure.

[0069] The two base patterns have sub-branches at various angles greater than 0 degrees and less than 90 degrees, and as the droplet converges (merged) into the main branch, the mass of the droplet increases, and as the increased mass increases, gravity also increases, allowing the droplet to be easily removed.

[0070] It includes a first electrode section and a second electrode section, wherein the first electrode section includes a first electrode connection section (111), a first base pattern electrode (112), a first branch electrode (113), and a first sub-branch electrode (114), and the second electrode section includes a second electrode connection section (121), a second base pattern electrode (122), a second branch electrode (123), and a second sub-branch electrode (124).

[0071] Although a rectangular planar pattern electrode structure was used as an example for the entire city, the outer shape of the planar surface including the characteristics of the branch electrode of the present invention can be applied in various ways, such as a circular shape.

[0072] Also, since the pattern electrode structure of the present invention is intended to receive an alternating voltage and cause a droplet on the electrode to vibrate and fall to self-clean, the plane formed by the entire structure must be a plane perpendicular to the horizontal plane or a plane inclined at a certain angle.

[0073] Therefore, the slope from the top to the bottom in the city can be less than 90 degrees.

[0074] The first electrode connection part (111) and the second electrode connection part (121) are configured to be connected to a power source to receive voltage, and the first base pattern electrode (112) and the second base pattern electrode (122) are each connected to the first electrode connection part (111) and the second electrode connection part (121) to form the outer circumference of the entire pattern electrode structure. That is, the first electrode connection part (111) forms a certain area of ​​the outer circumference, and the second electrode connection part (121) forms the remaining area of ​​the outer circumference.

[0075] The first branch electrode (113) and the second branch electrode (123) are arranged along one direction on the electrode structure, and the one direction is formed perpendicular to any plane perpendicular to the electrode structure, and are formed in multiple numbers spaced apart at equal intervals. As shown in the illustration, the first branch electrode (113) and the second branch electrode (123) are arranged alternately in the horizontal direction.

[0076] And, one end of each of the first branch electrode (113) and the second branch electrode (123) is connected to the first base pattern electrode (112) and the second base pattern electrode (122), and one end in the opposite direction is connected to the base pattern electrode.

[0077] Next, the first sub-branch electrode (114) is formed to extend downwardly from the first branch electrode (113) in both lateral directions, and a plurality of them are formed spaced apart from each other. That is, they are formed to extend in the lower right or lower left direction.

[0078] The first sub-branch electrode (114) is formed to be extended by a certain length and is formed at a certain distance from the first sub-branch electrode (114) branched from the adjacent first branch electrode (113), so that the second branch electrode (123) and the second sub-branch electrode (124) are arranged between the first branch electrode (113) and the first sub-branch electrode (114).

[0079] Accordingly, the second sub-branch electrode (124) is formed to extend upwardly from the second branch electrode (123) in both sides, and the direction of extension is, that is, the upper right direction or the upper left direction.

[0080] The second sub-branch electrode (124) is formed to be extended by a certain length and is formed at a certain distance from the second sub-branch electrode (124) branched from the adjacent second branch electrode (123), so that the second sub-branch electrode (124) is positioned in the area between a pair of first sub-branch electrodes (113).

[0081] In this way, the first sub-branch electrode (114) may be formed in the lower right or lower left direction, and the second sub-branch electrode (124) may be formed in the upper right or upper left direction, which are opposite to each other. That is, the first sub-branch electrode (114) may be in the upper right or upper left direction, and the second sub-branch electrode (124) may be in the lower right or lower left direction.

[0082] In addition, the first sub-branch electrode (114) can be formed so that it is all inclined downward and the second sub-branch electrode (124) can be formed so that it is all inclined downward, but it has a so-called shifted pattern structure rather than a structure that is completely symmetrical with respect to the sub-branch electrode as shown in the illustration.

[0083] In other words, the sub-branch electrode branching to the left and the sub-branch electrode branching to the right do not branch out to both sides at the same height as the branch electrode, but have a height difference.

[0084] In contrast, as shown in the application example of FIG. 12, the first sub-branch electrode (114-3, 114-4) can be configured to be completely left-right symmetric with respect to the first branch electrode (113), and the second sub-branch electrode (124-3, 124-4) can be configured to be completely left-right symmetric with respect to the second branch electrode (123).

[0085] Since water droplets are more likely to adhere to the surface if they are equal to or smaller than the width of the electrode, symmetric and asymmetric structures can be selected to minimize or intentionally increase the adhesion of water droplets. Additionally, for the same reason, the length, width, and end shape of the sub-branch patterns of the pattern can be varied.

[0086] According to the pattern electrode structure of the present invention configured as described above, droplets (D1, D2) falling in an inclined downward direction along the second sub-branch electrode as shown in FIG. 6 are combined at the branch electrode to increase in volume, thereby allowing them to fall easily along the branch electrode.

[0087] Next, FIG. 7 is an enlarged view of a part of a pattern electrode structure for an electrowetting device according to a second embodiment of the present invention, and FIGS. 8 to 10 show the movement state of a droplet in a pattern electrode structure for an electrowetting device according to a second embodiment of the present invention.

[0088] The first electrode connection part, the second electrode connection part, the first base pattern electrode, and the second base pattern electrode are identical to the pattern electrode structure according to the first embodiment.

[0089] And, the first branch electrode (213) and the second branch electrode (223) are arranged along one direction on the electrode structure, and the one direction is formed perpendicular to any plane perpendicular to the electrode structure, and are formed in multiple numbers spaced apart at equal intervals. As shown in the illustration, the first branch electrode (213) and the second branch electrode (223) are arranged alternately in the horizontal direction.

[0090] Next, the first sub-branch electrode is formed to extend in a slanted manner from the first branch electrode (213) to both sides, wherein the slanted directions of the first sub-branch electrode (214-1) extending to one side and the first sub-branch electrode (214-2) extending to the other side are different from each other. That is, in the example, the first sub-branch electrode (214-1) extending to the left side of the first branch electrode (213) in the illustration is formed to be slanted downward (downward to the left), and the first sub-branch electrode (214-2) extending to the right side of the first branch electrode (213) in the illustration is formed to be slanted upward (upward to the right), and such slanted directions may be formed in opposite directions.

[0091] The first sub-branch electrode (214-1, 214-2) is formed to extend a certain length and is formed at a certain distance from the first sub-branch electrode (214-1, 214-2) branched from the adjacent first branch electrode (213), so that the second branch electrode (223) and the second sub-branch electrode (224-1, 224-2) are arranged between the first branch electrode (213) and the first sub-branch electrode (214-1, 214-2).

[0092] Accordingly, the second sub-branch electrode is formed to extend in a slanted manner from the second branch electrode (223) to both sides, and the slanted directions of the second sub-branch electrode (224-1) extending to one side and the second sub-branch electrode (224-2) extending to the other side are different from each other. That is, in the example, the second sub-branch electrode (224-1) extending to the left side of the second branch electrode (223) in the illustration is formed to be slanted downward (downward to the left), and the second sub-branch electrode (224-2) extending to the right side of the second branch electrode (223) in the illustration is formed to be slanted upward (upward to the right), and such slanted directions can be formed in opposite directions.

[0093] The second sub-branch electrode is formed to be extended by a certain length and is formed at a certain distance from the second sub-branch electrode branched from the adjacent second branch electrode (223), so that the second sub-branch electrode (224-1, 224-2) is positioned in the area between a pair of first sub-branch electrodes (213-1, 213-2).

[0094] Meanwhile, as in the first application example of FIG. 13, the first sub-branch electrode (214-3, 214-4) having a origin-symmetric relationship can be arranged to branch out at the same height as the first branch electrode (213), whereas in the second embodiment of FIG. 7, it can be arranged to be shifted to branch out at a different height.

[0095] In addition, as shown in the second application example of FIG. 14, the length of the pattern may be variable according to the design intent and may vary depending on the position.

[0096] That is, as shown in the example, the lengths of the second sub-branch electrodes (424-2, 424-3) that are inclined upward in one direction from the second branch electrode (423) can be formed to be different. (A <B)

[0097] Generally, the width of the sub-branch pattern is designed to be smaller compared to the main branch pattern, because the purpose of the sub-branch pattern is often focused on moving small fluid droplets that are difficult to remove with the main branch pattern.

[0098] According to the pattern electrode structure of the present invention configured as described above, droplets (D1, D2) falling in an inclined downward direction along the second sub-branch electrode as shown in FIG. 6 are combined at the branch electrode to increase in volume, thereby allowing them to fall easily along the branch electrode.

[0099] In the example, the angle formed by the branch electrode and the sub-branch electrode can be 20 degrees, and depending on the purpose of use, it can be formed in various ways, such as 10 degrees.

[0100] Also, the width of the sub-branch electrode and the spacing between the first sub-branch electrode (214-1) and the second sub-branch electrode (224-2) can have various design dimensions.

[0101] The thinner the width, the easier it is to remove small water droplets, but it may be disadvantageous for removing large water droplets.

[0102] As shown in Fig. 7, when a droplet (D, fluid drop) is located in the first branch pattern or the second branch pattern and is large enough to span across an adjacent electrode, the fluid droplet has sufficient vibration and downward driving force necessary for falling and falls vertically.

[0103] As shown in FIG. 8, if the fluid droplet (D) is located in the first branch pattern (213) or the second branch pattern (223) and is small in size, it does not have a sufficient size to span across the neighboring electrode, so the fluid droplet does not have the vibration and downward driving force required for falling and may stick to the surface.

[0104] And, as shown in FIG. 9, when a fluid droplet (D) is located at the first sub-branch electrode (214-2) or the second sub-branch pattern (224-2), the fluid droplet has the vibration and downward driving force required for falling and descends along a pattern with an inclination angle to move to the first branch pattern or the second branch pattern.

[0105] And, as shown in FIG. 10, relatively small fluid droplets (d1, d2) that fell from the first and second sub-branch patterns to the first and second branch patterns meet with small fluid droplets that were stuck to the first and second branch patterns to form larger fluid droplets.

[0106] Therefore, by adjusting the electrode width and spacing of the first and second sub-branch patterns, movement of fluid droplets of various sizes can be created. (However, differences in movement speed occur depending on the pattern width, spacing, and size of the fluid droplets.)

[0107] Next, FIG. 11 illustrates a pattern electrode structure for an electrowetting device according to a third embodiment of the present invention, and only the configuration different from the previous embodiment will be described.

[0108] Unlike the preceding embodiment, the pattern electrode structure according to the third embodiment has a unilateral structure in which the first sub-branch electrode (314) and the second sub-branch electrode (324) are each formed to extend in a slanted direction only from the first branch electrode (313) and the second branch electrode (323), respectively. In the example, the first sub-branch electrode (314) is formed to extend upward to the right from one side, and the second sub-branch electrode (324) is formed to extend downward to the left from one side.

[0109] That is, the first sub-branch electrode (314) and the second sub-branch electrode (324) are formed to be positioned in the gap between each by extending in a direction opposite to each other.

[0110] Although the present invention has been described above with reference to the illustrated drawings, it is obvious to those skilled in the art that it is not limited to the described embodiments and can be modified and varied in various ways without departing from the spirit and scope of the invention. Accordingly, such modifications or variations should be deemed to fall within the scope of the claims of the present invention, and the scope of rights of the present invention should be interpreted based on the appended claims. Explanation of the symbols

[0111] 111: First electrode connection part 112: First base pattern electrode 113: 1st branch electrode 114: 1st sub-branch electrode 121: Second electrode connection part 122: Second base pattern electrode 123: 2nd branch electrode 125 : 2nd sub-branch electrode

Claims

Claim 1 A pattern electrode structure for an electro-wetting device, wherein the pattern electrode structure is laminated between a base material and a dielectric layer of the electro-wetting device, and comprises: a plurality of branch electrodes formed along a perpendicular direction to any plane perpendicular to the plane formed by the pattern electrode structure and spaced apart at a certain interval; and a plurality of sub-branch electrodes formed by extending a certain length in an inclined direction from each of the plurality of branch electrodes, wherein the sub-branch electrodes extending from one of the branch electrodes are formed to be disposed between sub-branch electrodes extending from an adjacent branch electrode, and the sub-branch electrodes extending from one of the branch electrodes and the sub-branch electrodes extending from an adjacent branch electrode are alternately arranged in a direction perpendicular to the arrangement direction of the plurality of branch electrodes. Claim 2 A pattern electrode structure for an electrowetting device according to claim 1, wherein the sub-branch electrode extending from one of the plurality of branch electrodes is formed at a certain distance from the sub-branch electrode extending from an adjacent branch electrode. Claim 3 A pattern electrode structure for an electro-wetting device according to claim 2, characterized in that a plurality of sub-branch electrodes are formed by branching out and extending from both sides of the branch electrode. Claim 4 A pattern electrode structure for an electrowetting device according to claim 3, characterized in that a plurality of sub-branch electrodes branched to both sides of the branch electrode are formed to be inclined in the same direction, either upward or downward. Claim 5 A pattern electrode structure for an electrowetting device according to claim 3, characterized in that, based on the branch electrode, the height at which a plurality of sub-branch electrodes branching to one side of the branch electrode branch off is different from the height at which a plurality of sub-branch electrodes branching to the other side of the branch electrode branch off. Claim 6 A pattern electrode structure for an electrowetting device according to claim 3, characterized in that, based on the branch electrode, the height at which a plurality of sub-branch electrodes branching to one side of the branch electrode and the height at which a plurality of sub-branch electrodes branching to the other side of the branch electrode are the same. Claim 7 A pattern electrode structure for an electrowetting device according to claim 3, characterized in that among the plurality of sub-branch electrodes branched to both sides of the branch electrode, the plurality of sub-branch electrodes branched to one side and the plurality of sub-branch electrodes branched to the other side have different inclination directions among the upward direction and the downward direction. Claim 8 A pattern electrode structure for an electrowetting device according to claim 7, characterized in that, based on the branch electrode, the height at which a plurality of sub-branch electrodes branching to one side of the branch electrode branch off is different from the height at which a plurality of sub-branch electrodes branching to the other side of the branch electrode branch off. Claim 9 A pattern electrode structure for an electrowetting device according to claim 7, characterized in that, based on the branch electrode, the height at which a plurality of sub-branch electrodes branching to one side of the branch electrode and the height at which a plurality of sub-branch electrodes branching to the other side of the branch electrode are the same. Claim 10 A pattern electrode structure for an electrowetting device according to claim 2, characterized in that a plurality of sub-branch electrodes are formed by branching and extending only to one side of the branch electrode. Claim 11 A pattern electrode structure comprising a first electrode portion and a second electrode portion, which is laminated between a base material and a dielectric layer of an electro-wetting device, wherein the first electrode portion is formed along a perpendicular direction to an arbitrary plane perpendicular to the plane formed by the pattern electrode structure and includes a plurality of first branch electrodes formed at regular intervals and a plurality of first sub-branch electrodes formed by extending a certain length in an inclined direction from each of the plurality of branch electrodes; the second electrode portion is formed along a perpendicular direction to an arbitrary plane perpendicular to the plane formed by the pattern electrode structure and includes a plurality of second branch electrodes formed at regular intervals and a plurality of second sub-branch electrodes formed by extending a certain length in an inclined direction from each of the plurality of branch electrodes; and wherein the plurality of first sub-branch electrodes and the plurality of second sub-branch electrodes are arranged such that the second sub-branch electrode is disposed between adjacent first sub-branch electrodes. A pattern electrode structure for an electrowetting device, characterized in that a plurality of first sub-branch electrodes and a plurality of adjacent second sub-branch electrodes are alternately arranged in a direction perpendicular to the arrangement direction of the plurality of branch electrodes. Claim 12 A pattern electrode structure for an electrowetting device according to claim 11, wherein the first branch electrode and the second branch electrode are alternately arranged in a horizontal direction, and the inclination direction of the first sub-branch electrode and the second sub-branch electrode, which are each branched in a direction opposite to the adjacent first branch electrode and the second branch electrode, is different from each other among the upward direction and the downward direction. Claim 13 delete Claim 14 A pattern electrode structure for an electrowetting device according to claim 12, wherein a plurality of first sub-branch electrodes are formed by branching out and extending from both sides of the first branch electrode, and a plurality of second sub-branch electrodes are formed by branching out and extending from both sides of the second branch electrode. Claim 15 A pattern electrode structure for an electrowetting device according to claim 14, wherein a plurality of first sub-branch electrodes branched to both sides of the first branch electrode are formed to be inclined in the same direction, either upward or downward, and a plurality of second sub-branch electrodes branched to both sides of the second branch electrode are formed to be inclined in the same direction, either upward or downward. Claim 16 A pattern electrode structure for an electrowetting device according to claim 15, wherein, based on the first branch electrode, the height at which a plurality of first sub-branch electrodes branching to one side of the first branch electrode branch is different from the height at which a plurality of first sub-branch electrodes branching to the other side of the first branch electrode branch is different, and based on the second branch electrode, the height at which a plurality of second sub-branch electrodes branching to one side of the second branch electrode branch is different from the height at which a plurality of second sub-branch electrodes branching to the other side of the second branch electrode branch is different. Claim 17 A pattern electrode structure for an electrowetting device according to claim 14, wherein the inclination direction of the plurality of first sub-branch electrodes branched to one side and the plurality of first sub-branch electrodes branched to the other side among the plurality of first sub-branch electrodes branched to both sides of the first branch electrode are different from each other between the upward direction and the downward direction, and wherein the inclination direction of the plurality of second sub-branch electrodes branched to one side and the plurality of second sub-branch electrodes branched to the other side among the plurality of second sub-branch electrodes branched to both sides of the second branch electrode are different from each other between the upward direction and the downward direction. Claim 18 A pattern electrode structure for an electrowetting device according to claim 17, wherein, with respect to the first branch electrode, the height at which a plurality of first sub-branch electrodes branching to one side of the first branch electrode branch is different from the height at which a plurality of first sub-branch electrodes branching to the other side of the first branch electrode branch is different, and with respect to the second branch electrode, the height at which a plurality of second sub-branch electrodes branching to one side of the second branch electrode branch is different from the height at which a plurality of second sub-branch electrodes branching to the other side of the second branch electrode branch is different. Claim 19 A pattern electrode structure for an electrowetting device according to claim 12, characterized in that a plurality of first sub-branch electrodes and a plurality of second sub-branch electrodes are each formed by branching and extending only to one side of the first branch electrode and the second branch electrode.

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