Discharge device

Abstract

A discharge device of the present disclosure has a discharge electrode, an opposing electrode, a voltage application circuit, and a liquid supply portion. The discharge electrode is a columnar electrode. The opposing electrode opposes the discharge electrode. The voltage application circuit applies an applied voltage between the discharge electrode and the opposing electrode. The liquid supply portion supplies a liquid to the discharge electrode. The liquid expands and contracts along a central axis of the discharge electrode due to discharge. The opposing electrode has a peripheral electrode portion and a protruding electrode portion. In a direction along the central axis of the discharge electrode, a tip of the liquid in a state in which the liquid is elongated is located at a position that is the same as an outer periphery of the peripheral electrode portion or is located at a position that is on the discharge electrode side than the outer periphery.

Description

[0001] This application is a divisional application of the application filed on July 16, 2020, with application number 202080065151.9 (international application number PCT / JP2020 / 027609) and entitled "Discharge Device and Electrode Device". Technical Field

[0002] This disclosure generally relates to discharge devices and electrode devices, and more specifically to discharge devices having discharge electrodes and counter electrodes, and electrode devices used in the discharge device. Background Technology

[0003] Patent Document 1 describes a discharge device comprising a discharge electrode and a counter electrode, wherein a discharge is generated by applying an external voltage between the discharge electrode and the counter electrode, which further develops into a self-corona discharge. The discharge generated by this device is an intermittent discharge that creates a discharge path extending from the self-discharge electrode outwards through insulation breakdown. Regarding the discharge device described in Patent Document 1, by generating a high-energy discharge, the amount of effective components generated can be increased compared to corona discharge.

[0004] Furthermore, Patent Document 1 describes a counter electrode having a needle-shaped electrode portion opposite to the discharge electrode. As a result, the discharge device stably generates a discharge path that occurs intermittently between the discharge electrode and the needle-shaped electrode portion.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-22574 Summary of the Invention

[0008] The purpose of this disclosure is to provide a discharge device and electrode device that can further improve the generation efficiency of effective components.

[0009] The discharge device disclosed herein includes a discharge electrode, a counter electrode, an applied voltage circuit, and a liquid supply unit. The discharge electrode is a cylindrical electrode. The counter electrode is opposite to the discharge electrode. The applied voltage circuit generates a discharge by applying an applied voltage between the discharge electrode and the counter electrode. The liquid supply unit supplies liquid to the discharge electrode. The liquid expands and contracts along the central axis of the discharge electrode due to the discharge. The counter electrode has a peripheral electrode portion and a protruding electrode portion. The peripheral electrode portion protrudes to the side opposite to the discharge electrode and has an opening at its top surface. The protruding electrode portion protrudes from the peripheral electrode portion into the opening. In the direction along the central axis of the discharge electrode, the top of the liquid in its expanded state is located at the same position as the outer periphery of the peripheral electrode portion or closer to the discharge electrode side than the outer periphery.

[0010] The electrode device of one of the technical solutions disclosed herein is an electrode device used in the discharge device, having the discharge electrode and the counter electrode, and having the applied voltage applied from the applied voltage circuit.

[0011] The discharge device disclosed herein includes a discharge electrode, a counter electrode, and an applied voltage circuit. The discharge electrode is a columnar electrode. The counter electrode is opposite to the discharge electrode. The applied voltage circuit generates a discharge by applying an external voltage between the discharge electrode and the counter electrode. The counter electrode has a peripheral electrode portion and a protruding electrode portion. The peripheral electrode portion protrudes to the side opposite to the discharge electrode and has an opening at its top surface. The protruding electrode portion protrudes from the peripheral electrode portion into the opening. Along the central axis of the discharge electrode, the top of the discharge electrode is located closer to the discharge electrode side than the outer periphery of the peripheral electrode portion.

[0012] According to this disclosure, it has the advantage of being able to further improve the generation efficiency of the active ingredient. Attached Figure Description

[0013] Figure 1A This is a perspective view schematically showing a partial cross-section of the main part of the electrode device of the discharge device of Embodiment 1.

[0014] Figure 1B This is a schematic cross-sectional view showing the main parts of the electrode device according to Embodiment 1.

[0015] Figure 2 This is a block diagram of the discharge device according to Embodiment 1.

[0016] Figure 3 This is a schematic perspective view showing the main parts of the discharge device according to Embodiment 1.

[0017] Figure 4 This is a schematic top view showing the main parts of the discharge device according to Embodiment 1.

[0018] Figure 5 This represents the main parts of the discharge device in Embodiment 1, and is... Figure 4 Sectional view along line A1-A1.

[0019] Figure 6A This is a top view of the counter electrode of the discharge device in Embodiment 1.

[0020] Figure 6B This is a bottom view of the counter electrode in Embodiment 1.

[0021] Figure 7A This is a top view showing the main part of the opposing electrode of the electrode device in Embodiment 1.

[0022] Figure 7B yes Figure 7A Sectional view along line A1-A1.

[0023] Figure 7C yes Figure 7A Sectional view along line B1-B1.

[0024] Figure 8A The diagram schematically shows the main parts of the electrode device of Embodiment 1, and is a cross-sectional view of the liquid elongation state.

[0025] Figure 8B The diagram schematically shows the main parts of the electrode device of Embodiment 1, and is a cross-sectional view of the liquid in a contracted state.

[0026] Figure 9A This is a schematic diagram illustrating the discharge pattern of corona discharge.

[0027] Figure 9B This is a schematic diagram illustrating the discharge mode of a full-circuit breakdown discharge.

[0028] Figure 9C This is a schematic diagram illustrating the discharge morphology of partial breakdown discharge.

[0029] Figure 10A This is a schematic top view showing the opposing electrode of the electrode device in Embodiment 2.

[0030] Figure 10B This is a schematic top view showing the opposing electrode of the electrode device in Embodiment 2.

[0031] Figure 10C This is a schematic top view showing the opposing electrode of the electrode device in Embodiment 2.

[0032] Figure 10D This is a schematic top view showing the opposing electrode of the electrode device in Embodiment 2. Detailed Implementation

[0033] (Implementation Method 1)

[0034] (1) Summary

[0035] The following is for reference Figure 1A , Figure 1B as well as Figure 2 This section provides an overview of the discharge device 10 and electrode device 3 in this embodiment.

[0036] like Figure 1A and Figure 1B As shown, the electrode device 3 of this embodiment includes a discharge electrode 1 and a counter electrode 2. This electrode device 3 is configured to discharge an external voltage V1 (refer to...) Figure 2 An external discharge is generated between the discharge electrode 1 and the counter electrode 2.

[0037] In addition, such as Figure 2 As shown, the electrode device 3, together with the voltage applied circuit 4 and the liquid supply unit 5, constitute the discharge device 10. In other words, the discharge device 10 of this embodiment includes the electrode device 3, the voltage applied circuit 4, and the liquid supply unit 5. The voltage applied circuit 4 generates a discharge by applying an applied voltage V1 between the discharge electrode 1 and the counter electrode 2. The liquid supply unit 5 supplies liquid 50 (see reference) to the discharge electrode 1. Figure 8A The discharge device 10 generates an effective ingredient by producing a discharge in the electrode device 3. The term "effective ingredient" as used in this disclosure refers to the component generated by the discharge in the electrode device 3, and as an example, includes charged microparticles containing OH radicals, OH radicals, O2 radicals, negative ions, positive ions, ozone, or nitrate ions. These effective ingredients are not limited to sterilization, deodorization, moisturizing, preservation, or virus deactivation, but also have useful effects in various situations.

[0038] In this discharge device 10, liquid 50 is electrostatically atomized using the discharge generated in the discharge device 10. Specifically, the discharge device 10 applies a voltage between the discharge electrode 1 and the counter electrode 2 from the voltage application circuit 4, for example, when liquid 50 supplied from the liquid supply unit 5 adheres to the surface of the discharge electrode 1 and liquid 50 is held on the discharge electrode 1. Therefore, when a discharge occurs between the discharge electrode 1 and the counter electrode 2, the liquid 50 held on the discharge electrode 1 is electrostatically atomized due to the discharge. Thus, the discharge device 10 of this embodiment constitutes an electrostatic atomization device (active ingredient generation system) that electrostatically atomizes liquid 50 using discharge and generates charged microparticle liquid as an active ingredient. In this disclosure, the liquid 50 held on the discharge electrode 1, i.e., the liquid 50 to be electrostatically atomized, is also simply referred to as "liquid 50".

[0039] In particular, in this embodiment, the applied voltage circuit 4 intermittently generates discharge by periodically varying the magnitude of the applied voltage V1. The periodic variation of the applied voltage V1 causes mechanical vibration in the liquid 50. The term "applied voltage" as used in this disclosure refers to the voltage applied by the applied voltage circuit 4 between the discharge electrode 1 and the counter electrode 2 to generate the discharge.

[0040] By applying an external voltage (V1) between the discharge electrode 1 and the counter electrode 2, the liquid 50 held at the discharge electrode 1 is subjected to a force generated by the electric field, forming a cone-shaped structure called a Taylor cone (see reference). Figure 8A (See below for details.) Then, the electric field concentrates at the tip (apex) of the Taylor cone, thereby generating a discharge. At this point, the sharper the tip of the Taylor cone, that is, the smaller the apex angle of the cone (the more acute the angle), the smaller the electric field strength required for insulation breakdown, and the easier it is to generate a discharge.

[0041] The liquid 50 held in the discharge electrode 1 vibrates mechanically along the central axis P1 of the discharge electrode 1 (refer to...). Figure 8B The liquid 50 stretches and contracts, thus alternating between shapes 1 and 2. The first shape is the state in which the liquid 50 elongates along the central axis P1 of the discharge electrode 1, i.e., the shape of a Taylor cone (see reference). Figure 8A The second shape is the state of liquid 50 contraction, that is, the shape of the top of the Taylor cone being flattened (see reference). Figure 8B As a result, due to the periodic formation of Taylor cones as described above, discharges are generated intermittently in conjunction with the timing of the formation of the Taylor cones.

[0042] Furthermore, the discharge device 10 of this embodiment, as described above, includes a discharge electrode 1, a counter electrode 2, a voltage external circuit 4, and a liquid supply unit 5. For example... Figure 1A and Figure 1BAs shown, discharge electrode 1 is a cylindrical electrode. Opposing electrode 2 is opposite to discharge electrode 1. Voltage application circuit 4 applies an external voltage V1 between discharge electrode 1 and opposing electrode 2, thereby generating a discharge. Liquid supply unit 5 supplies liquid 50 to discharge electrode 1. Liquid 50 expands and contracts along the central axis P1 of discharge electrode 1 due to the discharge. Opposing electrode 2 has a peripheral electrode portion 21 and a protruding electrode portion 22. The peripheral electrode portion 21 protrudes to the side opposite to discharge electrode 1. An opening 23 is formed on the top surface of the peripheral electrode portion 21. The protruding electrode portion 22 protrudes from the peripheral electrode portion 21 into the opening 23. In the direction along the central axis P1 of discharge electrode 1, the top of liquid 50 in its expanded state is located at the same position as the outer periphery 210 of the peripheral electrode portion 21 or closer to the discharge electrode 1 than the outer periphery 210 (see reference). Figure 8A ).

[0043] According to the above structure, when an external voltage (applied voltage V1) is applied between the discharge electrode 1 and the counter electrode 2, the electric field can be concentrated in the peripheral electrode portion 21 and the protruding electrode portion 22 of the counter electrode 2 opposite to the discharge electrode 1. However, since the protruding electrode portion 22 protrudes from the peripheral electrode portion 21 into the opening 23, the degree of electric field concentration at the protruding electrode portion 22 is higher than that at the peripheral electrode portion 21. Therefore, when the liquid 50 held on the discharge electrode 1 is subjected to the force generated by the electric field and forms a Taylor cone, the electric field tends to concentrate, for example, between the tip (apex) of the Taylor cone and the protruding electrode portion 22. Therefore, a high-energy discharge is generated between the liquid 50 and the protruding electrode portion 22, which can further develop the corona discharge generated in the liquid 50 held on the discharge electrode 1 into a high-energy discharge. As a result, a discharge path L1 (refer to) that is at least partially insulated is easily formed intermittently between the discharge electrode 1 and the counter electrode 2. Figure 9B The efficiency of generating effective ingredients is not easily reduced.

[0044] Furthermore, the peripheral electrode portion 21 protrudes to the side opposite to the discharge electrode 1, and an opening 23 is formed on the top surface of the peripheral electrode portion 21. Therefore, the electric field exerts a force on the liquid 50 held on the discharge electrode 1, attracting the liquid 50 towards the peripheral electrode portion 21. Also, in the direction along the central axis P1 of the discharge electrode 1, the top of the liquid 50 in its extended state is located at the same position as the outer periphery 210 of the peripheral electrode portion 21 or closer to the discharge electrode 1 than the outer periphery 210. Thus, when the liquid 50 held on the discharge electrode 1 undergoes mechanical vibration, for example, a force continuously acts on the liquid 50 in the direction that attracts the liquid 50 towards the peripheral electrode portion 21, thereby suppressing the amplitude of the liquid 50 to a small size. That is, even when the liquid 50 is in a contracted state, a bias is applied to the liquid 50 in a direction that attracts the liquid 50 towards the peripheral electrode portion 21, so the liquid 50 does not become a completely flattened shape, and the amount of deformation of the liquid 50 caused by the mechanical vibration of the liquid 50 can be suppressed to a small extent. As a result, the vibration frequency of the liquid 50 can be increased, and the generation efficiency of the effective component can be improved.

[0045] (2) Details

[0046] The following is for reference Figures 1A to 9C The following describes the detailed contents of the discharge device 10 and electrode device 3 of this embodiment.

[0047] Hereinafter, as an example, we define three mutually orthogonal axes: the X-axis, Y-axis, and Z-axis. In particular, the axis along the central axis P1 of the discharge electrode 1 is defined as the "Z-axis." Furthermore, the positive direction of the Z-axis is defined from the side of the opposing electrode 2 when viewed from the discharge electrode 1. The X-axis, Y-axis, and Z-axis are all imaginary axes; the arrows representing "X," "Y," and "Z" in the figure are merely for illustrative purposes and do not represent actual objects. Additionally, the directions described above are not intended to limit the orientation of the electrode device 3 during use.

[0048] (2.1) Overall Structure

[0049] As described above, the discharge device 10 of this embodiment is as follows: Figure 2 As shown, the device includes an electrode assembly 3, an external voltage circuit 4, and a liquid supply unit 5. The discharge device 10 of this embodiment includes an electrode assembly 3 and an external voltage circuit 4.

[0050] The electrode device 3 has a discharge electrode 1 and a counter electrode 2. Figure 2 The shapes of the discharge electrode 1 and the counter electrode 2 are schematically shown in the diagram. As described above, the electrode device 3 generates a discharge by applying an external voltage between the discharge electrode 1 and the counter electrode 2.

[0051] like Figure 1A and Figure 1B As shown, the discharge electrode 1 is a cylindrical electrode extending along the Z-axis. The discharge electrode 1 has a discharge portion 11 at one end (top portion) in the longitudinal direction (Z-axis direction), and a base portion 12 at the other end in the longitudinal direction (the end opposite to the top portion). Figure 5 The discharge electrode 1 is a needle-shaped electrode in which at least the discharge portion 11 is formed with a tapered tip. The term "tapered tip" is not limited to a shape where the tip sharply tapers to a point, such as... Figure 1A As shown, it also includes shapes with rounded corners at the top.

[0052] The counter electrode 2 is configured to face the discharge portion 11 of the discharge electrode 1. Furthermore, as described above, the counter electrode 2 has a peripheral electrode portion 21 and a protruding electrode portion 22. The peripheral electrode portion 21 is configured to surround the central axis P1 of the discharge electrode 1 when viewed from one side of the central axis P1. The protruding electrode portion 22, when viewed from one side of the central axis P1 of the discharge electrode 1 (the positive side of the Z-axis), protrudes from a portion of the peripheral electrode portion 21 toward the central axis P1 of the discharge electrode 1 in the circumferential direction.

[0053] In this embodiment, such as Figures 3-5 As shown, the counter electrode 2 has a plate-shaped portion 24 that is longer along the X-axis. Furthermore, as... Figure 5 As shown, along the direction (Z-axis direction) of the central axis P1 of discharge electrode 1, discharge electrode 1 is separated from counter electrode 2. In other words, as... Figure 5 As shown, the discharge electrode 1 and the counter electrode 2 are in a mutually separated position along the direction of the central axis P1 (Z-axis direction) of the discharge electrode 1.

[0054] Here, an opening 23 is formed in a portion of the plate portion 24, extending through the plate portion 24 along its thickness direction (Z-axis direction). The portion of the counter electrode 2 located around the opening 23 is called the peripheral electrode portion 21. Furthermore, the portion protruding from the peripheral electrode portion 21 into the opening 23 is called the protruding electrode portion 22.

[0055] The discharge electrode 1 and the counter electrode 2 are held in a housing 6 made of electrically insulating synthetic resin. As an example, the flat plate portion 24 utilizes multiple (four in this case) riveting protrusions 61 provided on the housing 6 (see reference). Figure 3 It is riveted to the housing 6 by means of heat riveting or other means. Thus, the counter electrode 2 is held to the housing 6.

[0056] Here, the positional relationship between the counter electrode 2 and the discharge electrode 1 is determined such that the thickness direction of the counter electrode 2 (the through direction of the opening 23) is aligned with the length direction (Z-axis direction) of the discharge electrode 1, and the discharge portion 11 of the discharge electrode 1 is located near the center of the opening 23 of the counter electrode 2. In other words, when viewed from one side of the central axis P1 of the discharge electrode 1 (the positive side of the Z-axis), the center of the opening 23 is located on the central axis P1 of the discharge electrode 1. That is, a gap (space) is ensured between the counter electrode 2 and the discharge electrode 1, at least through the opening 23 of the counter electrode 2. In other words, the counter electrode 2 is configured to face the discharge electrode 1 across the gap and is electrically insulated from the discharge electrode 1.

[0057] The more detailed shapes of the discharge electrode 1 and the counter electrode 2 of the electrode device 3 will be described in the “(2.3) Electrode Device” section.

[0058] The liquid supply unit 5 supplies liquid 50 for electrostatic atomization to the discharge electrode 1. As an example, the liquid supply unit 5 is implemented using a cooling device 51 that cools the discharge electrode 1 and generates condensation on it. Specifically, as an example, such as... Figure 5 As shown, the cooling device 51 has a heat sink 512 and a plurality of (two in the illustrated example) Peltier elements 511. The plurality of Peltier elements 511 are mechanically and electrically connected to the heat sink 512, for example by solder, and are held on the heat sink 512. Each of the plurality of Peltier elements 511 has one end (on the side of the heat sink 512) as a heat dissipation end and the other end (on the side opposite to the heat sink 512) as a heat absorption end.

[0059] In addition, multiple Peltier elements 511 are mechanically connected to the discharge electrode 1. Here, the discharge electrode 1 is mechanically connected to the cooling device 51 at its base end 12, and the multiple Peltier elements 511 are mechanically connected to the discharge electrode 1 at their heat-absorbing ends. That is, the discharge electrode 1 and the cooling device 51 (multiple Peltier elements 511) are thermally coupled.

[0060] For this cooling device 51, by energizing the plurality of Peltier elements 511, the discharge electrode 1, which is thermally coupled to the Peltier elements 511, can be cooled. At this time, the cooling device 51 cools the entire discharge electrode 1 via the base end 12. As a result, moisture in the air condenses and adheres to the surface of the discharge electrode 1 as condensation. That is, the liquid supply unit 5 is configured to cool the discharge electrode 1 and generate condensation as liquid 50 on the surface of the discharge electrode 1. In this structure, the liquid supply unit 5 can supply liquid 50 (condensation) to the discharge electrode 1 using moisture in the air, so it is not necessary to supply and replenish liquid to the discharge device 10.

[0061] The voltage applied circuit 4, together with the electrode device 3 and the liquid supply unit 5, constitutes the discharge device 10. As described above, it is a circuit that generates discharge by applying an applied voltage V1 between the discharge electrode 1 and the counter electrode 2.

[0062] like Figure 2 As shown, the voltage external circuit 4 includes a voltage generating circuit 41, a drive circuit 42, and a control circuit 43. Additionally, the voltage external circuit 4 also includes a limiting resistor R1. The voltage generating circuit 41 is a circuit that receives power from a power source to generate a voltage (external voltage V1) applied to the electrode device 3. Here, "power source" refers to a power source that supplies power to the voltage generating circuit 41 and the like for operation; as an example, it is a power source circuit that generates a DC voltage of a few V to tens of V. The drive circuit 42 is a circuit that drives the voltage generating circuit 41. The control circuit 43 controls the drive circuit 42, for example, based on a monitored object. Here, "monitored object" includes at least one of the output current and output voltage of the voltage external circuit 4.

[0063] The voltage generating circuit 41 is, for example, a DC / DC converter that boosts the input voltage from the power supply and outputs the boosted voltage as the applied voltage V1. The output voltage of the voltage generating circuit 41 is applied as the applied voltage V1 to the electrode device 3 (discharge electrode 1 and counter electrode 2).

[0064] The voltage generating circuit 41 is electrically connected to the electrode device 3 (discharge electrode 1 and counter electrode 2). The voltage generating circuit 41 applies a high voltage to the electrode device 3. Here, the voltage generating circuit 41 is configured to apply a high voltage between the discharge electrode 1 and the counter electrode 2, with the discharge electrode 1 as the negative terminal (grounded) and the counter electrode 2 as the positive terminal (positive). In other words, when the voltage generating circuit 4 applies a high voltage to the electrode device 3, a potential difference is generated between the discharge electrode 1 and the counter electrode 2, with the discharge electrode 1 side being at a low potential and the counter electrode 2 side being at a high potential. The "high voltage" referred to here is simply the voltage at which a full-circuit breakdown discharge or a partial breakdown discharge, as described later, occurs in the electrode device 3. For example, it is a voltage with a peak value of about 6.0 kV. Full-circuit breakdown discharge and partial breakdown discharge will be described in detail in the "(2.4) Discharge Mode" column. The high voltage applied to the electrode device 3 by the external voltage circuit 4 is not limited to about 6.0kV. For example, it can be appropriately set according to the shape of the discharge electrode 1 and the counter electrode 2 or the distance between the discharge electrode 1 and the counter electrode 2.

[0065] Additionally, a limiting resistor R1 is inserted between the voltage generating circuit 41 and the electrode device 3. In other words, the voltage application circuit 4 has a voltage generating circuit 41 that generates an applied voltage V1 and a limiting resistor R1 inserted between an output terminal of the voltage generating circuit 41 and the electrode device 3. The limiting resistor R1 is a resistor used to limit the peak value of the discharge current flowing after insulation breakdown. That is, the limiting resistor R1 has the following function: it protects the electrode device 3 and the voltage application circuit 4 from overcurrent by limiting the current flowing to the electrode device 3 during discharge.

[0066] In this embodiment, a limiting resistor R1 is inserted between the voltage generating circuit 41 and the counter electrode 2. As described above, the counter electrode 2 is the positive terminal, therefore the limiting resistor R1 is inserted between the output terminal of the high potential side of the voltage generating circuit 41 and the electrode device 3.

[0067] Here, the operating modes of the voltage applied circuit 4 include two modes: Mode 1 and Mode 2. Mode 1 is used to increase the applied voltage V1 over time, causing corona discharge to develop and forming a discharge path L1 between the discharge electrode 1 and the counter electrode 2, which is at least partially insulated, thereby generating a discharge current. Mode 2 is used to put the electrode device 3 in an overcurrent state and cut off the discharge current using the control circuit 43, etc. The "discharge current" referred to in this disclosure means a relatively large current flowing through the discharge path L1, excluding the small current of a few μA generated during corona discharge before the formation of the discharge path L1. The "overcurrent state" referred to in this disclosure means a state where the load decreases due to discharge, and a current exceeding a certain value flows to the electrode device 3.

[0068] In this embodiment, the control circuit 43 controls the voltage application circuit 4 by controlling the drive circuit 42. The control circuit 43 controls the drive circuit 42 in a manner that the voltage application circuit 4 alternately cycles between a first mode and a second mode during the driving period when the voltage application circuit 4 is driven. Here, the control circuit 43 switches between the first mode and the second mode at a driving frequency such that the magnitude of the applied voltage V1 from the voltage application circuit 4 to the electrode device 3 varies periodically with the driving frequency. The "driving period" referred to in this disclosure is the period during which the voltage application circuit 4 is driven to cause the electrode device 3 to discharge.

[0069] That is, the voltage applied circuit 4 does not maintain the voltage applied to the electrode device 3 containing the discharge electrode 1 at a constant value, but rather makes the voltage vary periodically at a driving frequency within a predetermined range. The voltage applied circuit 4 intermittently generates discharge by periodically varying the magnitude of the applied voltage V1. In other words, in coordination with the variation period of the applied voltage V1, a discharge path L1 is periodically formed and discharge occurs periodically. Hereinafter, the period during which discharge (full-circuit breakdown discharge or partial breakdown discharge) occurs will also be referred to as the "discharge period". As a result, the magnitude of the electrical energy acting on the liquid 50 held by the discharge electrode 1 varies periodically at the driving frequency, and as a result, the liquid 50 held by the discharge electrode 1 vibrates mechanically at the driving frequency.

[0070] Here, in order to increase the deformation of the liquid 50, it is preferable to set the frequency of the variation of the applied voltage V1, i.e., the driving frequency, within a predetermined range that includes the resonant frequency (natural vibration frequency) of the liquid 50 held at the discharge electrode 1, that is, a value near the resonant frequency of the liquid 50. The "predetermined range" referred to in this disclosure is a range of frequencies such that the mechanical vibration of the liquid 50 increases when the force (energy) applied to the liquid 50 vibrates at frequencies within this predetermined range, and a range with a lower limit and an upper limit defined based on the resonant frequency of the liquid 50. In other words, the driving frequency is set to a value near the resonant frequency of the liquid 50. In this case, the amplitude of the mechanical vibration of the liquid 50 that occurs with the variation of the applied voltage V1 becomes larger, resulting in an increase in the deformation of the liquid 50 caused by the mechanical vibration of the liquid 50. The resonant frequency of the liquid 50 depends, for example, on the volume (amount), surface tension, and viscosity of the liquid 50.

[0071] That is, in the discharge device 10 of this embodiment, the liquid 50 vibrates mechanically at a driving frequency near its resonant frequency, thereby vibrating with a relatively large amplitude. Therefore, the tip (apex) of the Taylor cone generated by the liquid 50 when the electric field is applied is formed into a sharper (acute angle) shape. Thus, compared to the case where the liquid 50 vibrates mechanically at a frequency deviating from its resonant frequency, the electric field strength required for insulation breakdown is reduced when the Taylor cone is formed, making discharge easier to occur. Therefore, even if there are deviations in the magnitude of the voltage (applied voltage V1) applied to the electrode device 3 by the voltage application circuit 4, deviations in the shape of the discharge electrode 1, or deviations in the amount (volume) of liquid 50 supplied to the discharge electrode 1, discharge can occur stably. Furthermore, the voltage application circuit 4 can suppress the magnitude of the voltage applied to the electrode device 3 containing the discharge electrode 1 to a relatively low level. Therefore, the construction of insulation countermeasures around the electrode device 3 can be simplified, or the withstand voltage of components such as the voltage application circuit 4 can be reduced.

[0072] However, in this embodiment, even when the liquid 50 is contracted, a deflection is applied to the liquid 50 in a direction that attracts the liquid 50 towards the peripheral electrode portion 21, thereby suppressing the deformation of the liquid 50 caused by mechanical vibration to a smaller extent. Therefore, the discharge device 10 of this embodiment can increase the vibration frequency of the liquid 50, thereby improving the generation efficiency of the effective component. For an explanation of the principle of increasing the vibration frequency of the liquid 50, please refer to the section "(2.5) Vibration Frequency of the Liquid".

[0073] (2.2) Actions

[0074] The discharge device 10 described above discharges by causing the external voltage circuit 4 to operate as follows, thereby causing the electrode device 3 (discharge electrode 1 and counter electrode 2) to discharge.

[0075] That is, during the period before the discharge path L1 is formed, the control circuit 43 sets the output voltage of the voltage applied circuit 4 as the monitoring target. When the monitoring target (output voltage) reaches or exceeds the maximum value α, the energy output from the voltage generation circuit 41 is reduced. After the discharge path L1 is formed, the control circuit 43 sets the output current of the voltage applied circuit 4 as the monitoring target. When the monitoring target (output current) reaches or exceeds the threshold, the energy output from the voltage generation circuit 41 is reduced. Thus, the voltage applied circuit 4 causes the voltage applied to the electrode device 3 to decrease, and operates in the second mode to cut off the discharge current by putting the electrode device 3 in an overcurrent state. In other words, the operating mode of the voltage applied circuit 4 switches from the first mode to the second mode.

[0076] At this time, both the output voltage and output current of the voltage applied circuit 4 decrease, so the control circuit 43 causes the drive circuit 42 to operate again. As a result, the voltage applied to the electrode device 3 increases over time, and corona discharge develops, forming a discharge path L1 between the discharge electrode 1 and the counter electrode 2 that is at least partially insulated.

[0077] During the driving period, the control circuit 43 repeatedly performs the above-described actions, thereby causing the voltage application circuit 4 to operate alternately in the first mode and the second mode. As a result, the amount of electrical energy acting on the liquid 50 held by the discharge electrode 1 varies periodically with the driving frequency, and the liquid 50 vibrates mechanically with the driving frequency.

[0078] In summary, by applying a voltage to the electrode device 3 containing the discharge electrode 1 through the self-voltage applied circuit 4, a force generated by the electric field acts on the liquid 50 held by the discharge electrode 1, causing the liquid 50 to deform. At this time, the force F1 acting on the liquid 50 held by the discharge electrode 1 is represented by the product of the charge q1 contained in the liquid 50 and the electric field E1 (F1 = q1 × E1). In particular, in this embodiment, since a voltage is applied between the counter electrode 2 and the discharge electrode 1, which are opposite to the discharge section 11 of the discharge electrode 1, the liquid 50 is subjected to a force in the direction of pulling towards the counter electrode 2 under the action of the electric field. As a result, as... Figure 8A As shown, the liquid 50 held in the discharge section 11 of the discharge electrode 1 is subjected to a force generated by the electric field, and extends along the central axis P1 (i.e., along the Z-axis) of the discharge electrode 1 towards the opposing electrode 2, forming a cone-shaped structure called a Taylor cone. If the voltage applied to the electrode device 3... Figure 8A As the state shown decreases, the force acting on liquid 50 also decreases due to the influence of the electric field, thus causing liquid 50 to deform. As a result, as... Figure 8B As shown, the liquid 50 held in the discharge section 11 of the discharge electrode 1 contracts.

[0079] Furthermore, by periodically varying the magnitude of the voltage applied to the electrode device 3 to drive the frequency, the liquid 50 held in the discharge electrode 1 is alternately deformed into... Figure 8A The shape shown and Figure 8B The shape shown. That is, in this embodiment, the discharge electrode 1 holds the liquid 50 in such a way that the discharge portion 11 is covered by the liquid 50. The liquid 50 expands and contracts along the central axis P1 (i.e., along the Z-axis direction) of the discharge electrode 1 due to discharge. Discharge occurs because the electric field is concentrated at the tip (apex) of the Taylor cone, therefore, as Figure 8A As shown, insulation breakdown occurs when the tip of the Taylor cone is sharp. Therefore, discharges (full-circuit breakdown discharge or partial breakdown discharge) occur intermittently in conjunction with the driving frequency.

[0080] As a result, the liquid 50 held at the discharge electrode 1 is electrostatically atomized due to discharge. Consequently, an effective component consisting of a liquid of charged nanoparticles containing free radicals is generated in the discharge device 10. The generated effective component (charged microparticle liquid) is released, for example, through the opening 23 of the counter electrode 2 to the surrounding area of ​​the discharge device 10.

[0081] (2.3) Electrode device

[0082] Next, refer to Figure 1A , Figure 1B as well as Figures 6A to 8B A more detailed description of the shape of the electrode assembly 3 (discharge electrode 1 and counter electrode 2) used in the discharge device 10 of this embodiment will be provided. Figure 1A, Figure 1B , Figure 8A as well as Figure 8B The main parts of the discharge electrode 1 and the counter electrode 2 constituting the electrode device 3 are schematically shown in the figure. For structures other than the discharge electrode 1 and the counter electrode 2, the figures are omitted as appropriate. Figure 1A It is along Figure 4 A schematic three-dimensional view after sectioning along line B1-B1. Figure 1B It is along Figure 4 A schematic cross-sectional view after cutting along line B1-B1. Figures 6A to 7C This diagram only shows the counter electrode 2.

[0083] That is, in this embodiment, as described above, the counter electrode 2 has a peripheral electrode portion 21 and a protruding electrode portion 22. The peripheral electrode portion 21 is configured such that, when viewed from one side of the central axis P1 of the discharge electrode 1 (i.e., when viewed from the Z-axis side), it surrounds the central axis P1 of the discharge electrode 1 (refer to...). Figure 7A When viewed from the side of the central axis P1 of the discharge electrode 1 (i.e., from the Z-axis side), the protruding electrode portion 22 protrudes from a portion of the peripheral electrode portion 21 in the circumferential direction toward the central axis P1 of the discharge electrode 1 (see reference). Figure 7A ).

[0084] As an example, discharge electrode 1 is formed of a conductive metallic material such as titanium alloy (Ti alloy). Figure 1A and Figure 1B As shown, the discharge electrode 1 is a cylindrical electrode extending along the Z-axis. The discharge electrode 1 has a discharge portion 11 at one end (top portion) in the length direction (Z-axis direction).

[0085] In this embodiment, the top end (discharge portion 11) of the discharge electrode 1 is generally hemispherical. In other words, the top surface of the discharge electrode 1, i.e., the surface facing the opposing electrode 2 in the Z-axis direction, includes a curved surface. In this embodiment, the surface of the discharge electrode 1 facing the opposing electrode 2 in the Z-axis direction (positive direction of the Z-axis) is designated as the discharge portion 11. When liquid 50 is supplied to the discharge electrode 1 using the liquid supply unit 5, the liquid 50 is held on the discharge electrode 1 (see reference 5) in such a way that it covers at least the discharge portion 11. Figure 8A and Figure 8B ).

[0086] On the other hand, as an example, the counter electrode 2 is formed of a conductive metallic material such as titanium alloy (Ti alloy). In this embodiment, the counter electrode 2 has a plate-shaped flat plate portion 24 as described above. Furthermore, as... Figures 6A to 7CAs shown, an opening 23 is formed in a portion of the plate portion 24, extending through the plate portion 24 along its thickness direction (Z-axis direction). The portion of the counter electrode 2 located around the opening 23 is called the peripheral electrode portion 21. Furthermore, the portion protruding from the peripheral electrode portion 21 into the opening 23 is called the protruding electrode portion 22.

[0087] Furthermore, the counter electrode 2 is provided with an extension portion 25 extending outward from the peripheral electrode portion 21. That is, in the discharge device 10 of this embodiment, the counter electrode 2 has an extension portion 25 in addition to the peripheral electrode portion 21, the protruding electrode portion 22 and the flat plate portion 24.

[0088] More specifically, a dome-shaped peripheral electrode portion 21 is formed in a portion of the flat plate portion 24, protruding away from the discharge electrode 1 in the direction of the central axis P1 (Z-axis direction) along the discharge electrode 1 (positive Z-axis direction). That is, the peripheral electrode portion 21 protrudes towards the side opposite to the discharge electrode 1 (positive Z-axis side). As an example, the peripheral electrode portion 21 is formed into a flat, hemispherical shell shape (dome-shaped) in the Z-axis direction by partially recessing the flat plate portion 24 through a deep drawing process. Figure 7B and Figure 7C As shown, the peripheral electrode portion 21 has an inner surface 212 that is recessed to the side opposite to the discharge electrode 1. The inner surface 212 is a sloped surface inclined relative to the central axis P1 of the discharge electrode 1 in such a way that the inner diameter of the end edge on the discharge electrode 1 side in the Z-axis direction is larger than the inner diameter of the end edge on the side opposite to the discharge electrode 1.

[0089] Furthermore, an opening 23 is formed in the center of the peripheral electrode portion 21. The opening 23 is formed on the top surface of the peripheral electrode portion 21, which protrudes towards the side opposite to the discharge electrode 1 (the positive side of the Z-axis). The opening 23 is circular and extends through the opposing electrode 2 along its thickness direction (Z-axis direction). In other words, the peripheral electrode portion 21 has a circular opening 23. Figure 7A In the diagram, the inner periphery 231 (i.e., the periphery of the opening 23) and the outer periphery 210 of the peripheral electrode portion 21 are represented by imaginary lines (double-dotted lines). In other words, in Figure 7A In the middle, the area between the two imaginary lines (double-dotted lines) that form concentric circles is the peripheral electrode section 21. The center of the opening 23 is located on the central axis P1 of the discharge electrode 1.

[0090] Furthermore, the protruding electrode portion 22 protrudes from the peripheral electrode portion 21 into the opening portion 23. Here, the protruding electrode portion 22 protrudes from the inner periphery 231 of the peripheral electrode portion 21 (i.e., the periphery of the opening portion 23) toward the center of the opening portion 23. In this embodiment, a plurality of protruding electrode portions 22 are provided. That is, in this embodiment, the counter electrode 2 has a plurality of protruding electrode portions 22.

[0091] The counter electrode 2 preferably has three or more protruding electrode portions 22. In this embodiment, as an example, the counter electrode 2 has four protruding electrode portions 22. By having three or more protruding electrode portions 22, the electric field concentration at the protruding electrode portions 22 can be mitigated compared to the case where there are two or fewer protruding electrode portions 22. The plurality of protruding electrode portions 22 protrude from a local circumferential direction of the peripheral electrode portion 21 toward the central axis P1 of the discharge electrode 1.

[0092] Here, multiple (four in this case) protruding electrode portions 22 are arranged at equal intervals around the peripheral electrode portion 21. That is, the multiple protruding electrode portions 22 are arranged at equal intervals around the opening 23. In this embodiment, the counter electrode 2 has four protruding electrode portions 22, and therefore, these four protruding electrode portions 22 are positioned at a 90-degree rotational symmetry along the circumference of the peripheral electrode portion 21 (the circumference of the opening 23). That is, the multiple protruding electrode portions 22 are positioned at a point symmetrical about the center of the opening 23. Figure 7A In this design, with the positive direction of the X-axis (to the right) defined as "0 degrees" and the positive direction of the Y-axis (above) defined as "90 degrees", the four protruding electrode portions 22 are respectively positioned at 45 degrees, 135 degrees, 225 degrees, and 315 degrees. As an example, the opening portion 23 and the multiple protruding electrode portions 22 described above are formed by punching.

[0093] Furthermore, the multiple (four in this case) protruding electrode portions 22 share a common shape. In other words, the multiple protruding electrode portions 22 have a shape that is rotationally symmetrical about 90 degrees with respect to the central axis P1 of the discharge electrode 1. Therefore, the distance from the discharge portion 11 located on the central axis P1 of the discharge electrode 1 to the protruding electrode portions 22 is approximately equal for the multiple protruding electrode portions 22.

[0094] Furthermore, the electrode device 3 in this embodiment is configured such that, in order to increase the amount of effective components generated, a discharge path L1, at least partially insulated, is intermittently formed between the discharge portion 11 of the discharge electrode 1 and the protruding electrode portion 22 of the counter electrode 2. In this case, in order to reduce the amount of ozone generated, it is preferable to concentrate the electric field at the top end of the protruding electrode portion 22.

[0095] Therefore, for example, such as Figure 7AAs shown, the protruding electrode portion 22 is preferably arc-shaped as a whole when viewed from above. In other words, preferably, when viewed from the side of the central axis P1 of the discharge electrode 1 (i.e., from the Z-axis side), the outer periphery of the protruding electrode portion 22 is arc-shaped as a whole. The term "arc-shaped" in this disclosure is not limited to a partial shape as a perfect circle, but also includes an overall shape such as an R-surface (curved surface) with approximately the same radius of curvature at its top. That is, the top surface 221 of the protruding electrode portion 22 is as follows... Figure 7A As shown, it is arc-shaped when viewed from above. With this shape, the electric field does not act uniformly across the entire top surface 221 of the protruding electrode portion 22 when viewed from above. Instead, the electric field tends to concentrate at the vertex of the top surface 221 of the protruding electrode portion 22, which has the shortest distance to the discharge electrode 1 (especially the discharge portion 11) when viewed from above. As a result, it has the advantage of easily stabilizing the discharge between the discharge portion 11 and the protruding electrode portion 22.

[0096] Furthermore, if the top surface 221 (apex) of the protruding electrode portion 22 is sharp when viewed from above, this portion is prone to electrolytic corrosion due to electric field concentration, and the discharge state may change over time. Therefore, in order to prevent the discharge state from changing over time, it is preferable that the top surface 221 of the protruding electrode portion 22 when viewed from above includes a curved surface.

[0097] Furthermore, the degree of electric field concentration at the counter electrode 2 varies depending on the shape of the opposing surface of the counter electrode 2 opposite to the discharge electrode 1 (particularly the discharge section 11). In this embodiment, the electric field concentration at the counter electrode 2 is slightly mitigated by making the opposing surface of the counter electrode 2 opposite to the discharge electrode 1 (particularly the discharge section 11) an R-surface (curved surface). Specifically, at least one of the following four portions of the counter electrode 2 includes an R-surface. The first portion is as follows: Figure 7A The top surface 221 of the protruding electrode portion 22 is shown when viewed from one side of the central axis P1 of the discharge electrode 1. The second part is as follows: Figure 7C The diagram shows an imaginary plane VP1 containing the central axis P1 of the discharge electrode 1 and the top of the protruding electrode portion 22 (see reference). Figure 8A The corner 222 of the protruding electrode portion 22 on the side near the discharge electrode 1 within the ) . The third part is as follows Figure 7C The corner 211 of the peripheral electrode section 21 on the side near the discharge electrode 1 within the hypothetical plane VP1 shown. The fourth part is as follows. Figure 7C The inner surface 212 of the peripheral electrode portion 21 within the hypothetical plane VP1 shown. Figure 8A and Figure 8B This is a cross-sectional view taken with an imaginary plane VP1 that includes the central axis P1 of the discharge electrode 1 and the top of the protruding electrode portion 22.

[0098] In this embodiment, all four portions include curved shapes. That is, the top surface 221 of the protruding electrode portion 22 when viewed from above, as well as the corner portions 222, 211, and inner surface 212 within the imaginary plane VP1, all include curved shapes. Furthermore, in this embodiment, in addition to these four portions, the inner periphery 231 (periphery of the opening 23) of the peripheral electrode portion 21 when viewed from one side of the central axis P1 of the discharge electrode 1 (when viewed from above) also includes curved shapes.

[0099] The corner 211 of the peripheral electrode portion 21 is formed from the corner of the peripheral electrode portion 21 located closest to the discharge portion 11. In this embodiment, the corner 211 is the edge of the inner surface 212 of the dome-shaped peripheral electrode portion 21 on the discharge electrode 1 side in the Z-axis direction. In other words, the corner 211 is the corner between the surface (inner surface 212) of the peripheral electrode portion 21 facing the central axis P1 of the discharge electrode 1 and the surface facing the negative Z-axis. The corner 211 is formed over the entire circumference of the peripheral electrode portion 21. Therefore, the corner 211 is formed to be a circle centered on the central axis P1 when viewed from the side of the central axis P1 of the discharge electrode 1. Thus, the distance from the discharge portion 11 located on the central axis P1 of the discharge electrode 1 to the corner 211 is approximately equal over the entire circumference of the corner 211.

[0100] The corner 222 of the protruding electrode portion 22 is formed by the corner of the protruding electrode portion 22 located closest to the discharge portion 11. In this embodiment, the corner 222 is the edge of the apex of the protruding electrode portion 22, which is formed as an arc when viewed from above, on the side of the discharge electrode 1 in the Z-axis direction. In other words, the corner 222 is the corner between the surface of the protruding electrode portion 22 facing the central axis P1 of the discharge electrode 1 and the surface facing the negative Z-axis. Here, the distance from the discharge portion 11 located on the central axis P1 of the discharge electrode 1 to the corner 222 is approximately equal for the plurality of (here, four) protruding electrode portions 22.

[0101] More specifically, all five portions are formed in an arc shape. Furthermore, the inner surface 212 and inner periphery 231 of the peripheral electrode portion 21 are arc-shaped, protruding towards the side opposite to the discharge portion 11, i.e., with the discharge portion 11 side as the concave surface. On the other hand, the top surface 221 of the protruding electrode portion 22, the corner 211 of the peripheral electrode portion 21, and the corner 222 of the protruding electrode portion 22 are arc-shaped, protruding towards the discharge portion 11. Moreover, the radii of curvature of the bending shapes of these five portions preferably satisfy the following relationship: Starting from the side with the larger radius of curvature, the five portions are, in order: the inner surface 212 of the peripheral electrode portion 21, the inner periphery 231 of the peripheral electrode portion 21, the top surface 221 of the protruding electrode portion 22, the corner 211 of the peripheral electrode portion 21, and the corner 222 of the protruding electrode portion 22.

[0102] In summary, the radius of curvature of the inner surface 212 of the peripheral electrode portion 21 is the largest. Furthermore, the radius of curvature of the curved shape of the top surface 221 of the protruding electrode portion 22 is larger than the radius of curvature of the curved shape of the corner 222 on the discharge electrode 1 side of the protruding electrode portion 22. That is, compared to the top surface 221 of the protruding electrode portion 22 when viewed from above, the radius of curvature of the corner 222 on the discharge electrode 1 side of the protruding electrode portion 22 within the imaginary plane VP1 is smaller. Additionally, the radius of curvature of the curved shape of the top surface 221 of the protruding electrode portion 22 is smaller than the radius of curvature of the curved shape of the inner surface 212 of the peripheral electrode portion 21. That is, compared to the top surface 221 of the protruding electrode portion 22 when viewed from above, the radius of curvature of the inner surface 212 of the peripheral electrode portion 21 within the imaginary plane VP1 is larger. As an example, the radius of curvature of the inner periphery 231 of the peripheral electrode portion 21 is preferably 2.0 mm or more and 5.0 mm or less. More specifically, the radius of curvature of the inner periphery 231 of the peripheral electrode portion 21 is preferably 3.5 mm or less.

[0103] The extension portion 25 is the portion that extends outward from the peripheral electrode portion 21. For example... Figure 7B and Figure 7CAs shown, the epitaxial portion 25 is formed such that the further away from the peripheral electrode portion 21 it is, the further away from the discharge electrode 1 it is in the direction along the central axis P1 of the discharge electrode 1. In this embodiment, the epitaxial portion 25 is located around the peripheral electrode portion 21, connecting the plate portion 24 and the peripheral electrode portion 21. That is, when viewed from the side of the central axis P1 of the discharge electrode 1 (viewed from above), the peripheral electrode portion 21 and the epitaxial portion 25 are formed as concentric circles centered on the central axis P1. Moreover, in the epitaxial portion 25, taking the inner peripheral portion connected to the peripheral electrode portion 21 as a reference, the outer peripheral portion connected to the plate portion 24 is located on the side opposite to the discharge electrode 1 in the direction along the central axis P1 of the discharge electrode 1, that is, the positive side of the Z-axis. In other words, the epitaxial portion 25 is inclined relative to the central axis P1 of the discharge electrode 1 in such a way that the inner diameter of the end edge on the discharge electrode 1 side in the Z-axis direction is smaller than the inner diameter of the end edge on the side opposite to the discharge electrode 1 (plate portion 24 side).

[0104] Therefore, the counter electrode 2 is as follows Figure 7B and Figure 7C As shown, the shape extends in the negative Z-axis direction from the opening 23 toward the outer periphery (the side of the flat plate 24) and further extends in the positive Z-axis direction from its top. Thus, in the opposing electrode 2, a recess (groove) with a roughly V-shaped cross-section, recessed in the negative Z-axis direction, is formed around the opening 23 across its entire circumference. As an example, the epitaxial portion 25 is formed together with the peripheral electrode portion 21 by partially recessing the flat plate portion 24 through a deep drawing process.

[0105] By having such an extension portion 25, the portion of the counter electrode 2, except for the peripheral electrode portion 21 and the protruding electrode portion 22, can be moved away from the discharge electrode 1 (especially the discharge portion 11). In summary, by moving the portion outside the outer periphery 210 of the peripheral electrode portion 21 of the counter electrode 2 away from the discharge electrode 1 in the Z-axis direction, it is possible to suppress the generation of an unwanted electric field between the extension portion 25 or the plate portion 24 and the discharge electrode 1. As a result, an electric field can be generated efficiently between the peripheral electrode portion 21 and the protruding electrode portion 22 of the counter electrode 2 and the discharge electrode 1.

[0106] In addition, such as Figure 1A and Figure 1B As shown, the distance D1 from the peripheral electrode portion 21 to the discharge electrode 1 is greater than or equal to the distance D2 from the protruding electrode portion 22 to the discharge electrode 1 (D1≥D2). Preferably, the distance D1 from the peripheral electrode portion 21 to the discharge electrode 1 is longer than the distance D2 from the protruding electrode portion 22 to the discharge electrode 1.

[0107] In this disclosure, "distance D1" refers to the shortest distance from the peripheral electrode portion 21 to the discharge electrode 1, which in this embodiment is the length of the line segment connecting a point at the corner 211 of the peripheral electrode portion 21 and a point at the discharge portion 11. Similarly, "distance D2" refers to the shortest distance from the protruding electrode portion 22 to the discharge electrode 1, which in this embodiment is the length of the line segment connecting a point at the corner 222 of the protruding electrode portion 22 and a point at the discharge portion 11. That is, distance D1 from the peripheral electrode portion 21 to the discharge portion 11 is the distance from the corner 211 to the discharge portion 11. Distance D2 from the protruding electrode portion 22 to the discharge portion 11 is the distance from the corner 222 to the discharge portion 11.

[0108] Furthermore, in this embodiment, as described above, the liquid 50 is held on the discharge electrode 1 to cover the discharge section 11, and the liquid 50 expands and contracts along the central axis P1 (i.e., along the Z-axis direction) of the discharge electrode 1 due to discharge. Here, in the state where the liquid 50 is stretched along the central axis P1 of the discharge electrode 1, as... Figure 8A As shown, liquid 50 takes the shape of a Taylor cone (shape 1). On the other hand, in the contracted state of liquid 50, as... Figure 8B As shown, liquid 50 becomes a shape where the tip of the Taylor cone is flattened (shape 2).

[0109] Moreover, such as Figure 8A As shown, when the liquid 50 is in an elongated state (first shape), it is preferable to specify the distance from the peripheral electrode portion 21 and the protruding electrode portion 22 based on the liquid 50, instead of the discharge portion 11, as follows. That is, as Figure 8A As shown, in the extended state of the liquid 50, the distance D3 from the liquid 50 to the peripheral electrode 21 is greater than or equal to the distance D4 from the liquid 50 to the protruding electrode 22 (D3≥D4).

[0110] The "distance D3" mentioned in this disclosure refers to the shortest distance from the elongated liquid 50 to the peripheral electrode portion 21, and in this embodiment, it is the length of the line segment connecting a point at the corner 211 of the peripheral electrode portion 21 to the vertex of the first-shaped liquid 50. Similarly, the "distance D4" mentioned in this disclosure refers to the shortest distance from the elongated liquid 50 to the protruding electrode portion 22, and in this embodiment, it is the length of the line segment connecting a point at the corner 222 of the protruding electrode portion 22 to the vertex of the first-shaped liquid 50. In other words, the distance D3 from the liquid 50 to the peripheral electrode portion 21 is the distance from the corner 211 to the first-shaped (Taylor cone) liquid 50. The distance D4 from the liquid 50 to the protruding electrode portion 22 is the distance from the corner 222 to the first-shaped (Taylor cone) liquid 50.

[0111] Here, within the imaginary plane VP1 encompassing the central axis P1 of the discharge electrode 1 and the tip of the protruding electrode portion 22, the inclination angle θ1 of the imaginary line connecting the liquid 50 and the tip of the protruding electrode portion 22 relative to the central axis P1 of the discharge electrode 1 is 67 degrees or less. The "imaginary line connecting the liquid 50 and the tip of the protruding electrode portion 22" referred to here means the shortest distance from the extended liquid 50 to the protruding electrode portion 22, which is the line segment connecting a point at the corner 222 of the protruding electrode portion 22 and the vertex of the first-shaped liquid 50. Figure 8A (The arrow in the image represents the distance to D4).

[0112] And, as Figure 8B As shown, when the liquid 50 is in a contracted state (second shape), it is preferable to specify the distance from the peripheral electrode portion 21 and the protruding electrode portion 22 based on the liquid 50, instead of the discharge portion 11. That is, as follows: Figure 8B As shown, when the liquid 50 is in a contracted state, the distance D5 from the liquid 50 to the peripheral electrode 21 is greater than or equal to the distance D6 from the liquid 50 to the protruding electrode 22 (D5≥D6).

[0113] The "distance D5" mentioned in this disclosure refers to the shortest distance from the liquid 50 in a contracted state to the peripheral electrode portion 21. In this embodiment, it is the length of the line segment connecting a point at the corner 211 of the peripheral electrode portion 21 and the vertex of the second-shaped liquid 50. Similarly, the "distance D6" mentioned in this disclosure refers to the shortest distance from the liquid 50 in a contracted state to the protruding electrode portion 22. In this embodiment, it is the length of the line segment connecting a point at the corner 222 of the protruding electrode portion 22 and the vertex of the second-shaped liquid 50. That is, the distance D5 from the liquid 50 to the peripheral electrode portion 21 is the distance from the corner 211 to the second-shaped (the shape where the tip of a Taylor cone is flattened) liquid 50. The distance D6 from the liquid 50 to the protruding electrode portion 22 is the distance from the corner 222 to the second-shaped (the shape where the tip of a Taylor cone is flattened) liquid 50.

[0114] Here, within the imaginary plane VP1 encompassing the central axis P1 of the discharge electrode 1 and the tip of the protruding electrode portion 22, the angle θ2 of the imaginary line connecting the liquid 50 and the tip of the protruding electrode portion 22 relative to the central axis P1 of the discharge electrode 1 is 67 degrees or less. The "imaginary line connecting the liquid 50 and the tip of the protruding electrode portion 22" refers to the shortest distance from the liquid 50 in its contracted state to the protruding electrode portion 22, which is the line segment connecting a point at the corner 222 of the protruding electrode portion 22 and the apex of the second-shaped liquid 50. Figure 8B (The arrow in the image represents the distance to D6).

[0115] Thus, in this embodiment, the distance (D4 or D6) from the liquid 50 to the protruding electrode portion 22 is less than or equal to the distance (D3 or D5) from the liquid 50 to the peripheral electrode portion 21. Furthermore, in this embodiment, the distance from the liquid 50 to the protruding electrode portion 22 is shorter than the distance from the liquid 50 to the peripheral electrode portion 21 (D4 < D3 or D6 < D5). More specifically, the distance (D4 or D6) from the liquid 50 to the protruding electrode portion 22 is preferably 9 / 10 or less of the distance (D3 or D5) from the liquid 50 to the peripheral electrode portion 21.

[0116] Furthermore, within the imaginary plane VP1 encompassing the central axis P1 of the discharge electrode 1 and the top end of the protruding electrode portion 22, the inclination angles θ1 and θ2 of the imaginary line connecting the liquid 50 and the top end of the protruding electrode portion 22 relative to the central axis P1 of the discharge electrode 1 are 67 degrees or less. More preferably, the inclination angles θ1 and θ2 of the imaginary line relative to the central axis P1 of the discharge electrode 1 are 65 degrees or less, and even more preferably 62 degrees or less.

[0117] Here, the preferred relationship between the distances D3 to D6 and the tilt angles θ1 and θ2 is as follows: Figure 8A The liquid 50 is shown in an elongated state (shape 1) and Figure 8B The condition is valid under the condition that the liquid 50 is in a contracted state (shape 2).

[0118] The electrode device 3 of this embodiment has the following advantages by employing the distance relationship D1 to D6 as described above. Specifically, since the distance D1 from the peripheral electrode portion 21 to the discharge portion 11 is greater than or equal to the distance D2 from the protruding electrode portion 22 to the discharge portion 11, when an external voltage is applied between the discharge electrode 1 and the counter electrode 2, the electric field acting between the protruding electrode portion 22 and the discharge portion 11 becomes dominant. At this time, corona discharge is more likely to occur. Therefore, glow discharge or arc discharge, which can lead to continuous insulation breakdown, is less likely to occur, thus reducing the efficiency of effective component generation caused by glow discharge or arc discharge.

[0119] Furthermore, when the liquid 50 held at the discharge electrode 1 forms a Taylor cone due to the force generated by the electric field, the distance D3 from the (elongated) liquid 50 to the peripheral electrode portion 21 is longer than the distance D4 from the liquid 50 to the protruding electrode portion 22. Therefore, the electric field tends to concentrate between the apex of the Taylor cone and the protruding electrode portion 22. Consequently, a higher energy discharge is generated between the liquid 50 and the protruding electrode portion 22, allowing the corona discharge generated in the liquid 50 held by the discharge electrode 1 to further develop into a high-energy discharge. As a result, a discharge path L1, at least partially insulated, is formed between the discharge electrode 1 and the counter electrode 2.

[0120] However, in Figure 8A and Figure 8B In this disclosure, the liquid 50 in the discharge device 10 is sought to be in a stable state. The term "stable state" as used herein refers to a state in which the amount of liquid 50 held at the discharge electrode 1 is maintained at a substantially constant level. That is, the amount of liquid 50 supplied from the liquid supply unit 5 relative to the discharge electrode 1 is substantially balanced with the amount of liquid 50 released from the discharge device 10 due to electrostatic atomization, thereby maintaining a substantially constant and stable amount of liquid 50. The distances D3 to D6 are defined based on liquid 50 in such a stable state.

[0121] Furthermore, in this embodiment, as described above, in the direction along the central axis P1 of the discharge electrode 1, the tip of the liquid 50 in its elongated state is located at the same position as the outer periphery 210 of the peripheral electrode portion 21 or at a position closer to the discharge electrode 1 than the outer periphery 210 (see reference). Figure 8A That is, such as Figure 8A As shown, in the elongated state (first shape), the apex (top) of the liquid 50 is located in the Z-axis direction at the same position as the outer periphery 210 of the peripheral electrode portion 21 or closer to the discharge electrode 1 (the negative side of the Z-axis) than the outer periphery 210. That is, when a plane orthogonal to the Z-axis is imagined, and which includes the outer periphery 210 of the peripheral electrode portion 21, the apex (top) of the liquid 50 in the first shape is located in this plane or closer to the negative side of the Z-axis than this plane.

[0122] According to this structure, an electric field can be used to consistently exert a force on the liquid 50 held at the discharge electrode 1, attracting the liquid 50 towards the peripheral electrode portion 21. In short, the peripheral electrode portion 21 and the protruding electrode portion 22 of the counter electrode 2, which exert an electric field with the liquid 50, are always located on the positive side of the Z-axis when viewed from the liquid 50, thus consistently exerting a positive force on the liquid 50 towards the Z-axis. Therefore, when the liquid 50 held at the discharge electrode 1 undergoes mechanical vibration, for example, a force is continuously applied to the liquid 50 in the direction of attracting the liquid 50 towards the peripheral electrode portion 21, thereby suppressing the amplitude of the liquid 50 to a small extent. That is, even in the state of liquid 50 contraction, a deflection is applied to the liquid 50 in the direction of attracting the liquid 50 towards the peripheral electrode portion 21, so the liquid 50 does not become a completely flattened shape, and the amount of deformation of the liquid 50 caused by mechanical vibration can be suppressed to a small extent. As a result, the vibration frequency of the liquid 50 can be increased, and the generation efficiency of the effective component can be improved.

[0123] In addition, such as Figure 1A and Figure 1BAs shown, in the absence of liquid 50, the structure of the discharge device 10 of this embodiment is as follows. That is, the discharge device 10 of this embodiment includes a discharge electrode 1, a counter electrode 2, and a voltage application circuit 4. The discharge electrode 1 is a columnar electrode. The counter electrode 2 is opposite to the discharge electrode 1. The voltage application circuit 4 generates a discharge by applying an external voltage V1 between the discharge electrode 1 and the counter electrode 2. The counter electrode 2 has a peripheral electrode portion 21 and a protruding electrode portion 22. The peripheral electrode portion 21 protrudes to the side opposite to the discharge electrode 1. An opening 23 is formed on the top surface of the peripheral electrode portion 21. The protruding electrode portion 22 protrudes from the peripheral electrode portion 21 into the opening 23. In the direction along the central axis P1 of the discharge electrode 1, the top of the discharge electrode 1 is located closer to the discharge electrode 1 side than the outer periphery 210 of the peripheral electrode portion 21.

[0124] Thus, when the tip of the discharge electrode 1 is located closer to the discharge electrode 1 side than the outer periphery 210 of the peripheral electrode portion 21 along the direction of the central axis P1 of the discharge electrode 1, the same effect as described above can be expected. That is, the electric field can always exert a force on the liquid 50 held at the discharge electrode 1, attracting the liquid 50 towards the peripheral electrode portion 21. As a result, the vibration frequency of the liquid 50 can be increased, and the generation efficiency of the effective component can be improved.

[0125] (2.4) Discharge method

[0126] The following is for reference Figures 9A to 9C This section describes in detail the discharge pattern that occurs when an external voltage V1 is applied between the discharge electrode 1 and the counter electrode 2. Figures 9A to 9C This is a conceptual diagram used to illustrate the discharge morphology. Figures 9A to 9C The discharge electrode 1 and the counter electrode 2 are schematically shown. Furthermore, regarding the discharge device 10 of this embodiment, liquid 50 is actually held at the discharge electrode 1, and discharge occurs between the liquid 50 and the counter electrode 2. Figures 9A to 9C The illustration of liquid 50 is omitted. In addition, the following description assumes that there is no liquid 50 in the discharge section 11 of the discharge electrode 1. However, when liquid 50 is present, the term "discharge section 11 of the discharge electrode 1" can be replaced with "liquid 50 held in the discharge electrode 1" to indicate the location where the discharge occurs.

[0127] Here, first refer to Figure 9A This describes corona discharge.

[0128] Typically, when energy is applied between a pair of electrodes to generate a discharge, the discharge mode evolves from corona discharge to glow discharge or arc discharge, depending on the amount of energy applied.

[0129] Glow discharge and arc discharge are discharges accompanied by insulation breakdown between a pair of electrodes. In glow discharge and arc discharge, during the period when energy is applied between the electrodes, the discharge path formed by insulation breakdown is maintained, thereby continuously generating a discharge current between the electrodes. In contrast, such as Figure 9A As shown, corona discharge is a discharge that occurs locally on one electrode (discharge electrode 1) and is not accompanied by insulation breakdown between a pair of electrodes (discharge electrode 1 and counter electrode 2). In short, by applying an external voltage V1 between discharge electrode 1 and counter electrode 2, a localized corona discharge occurs at the discharge portion 11 of discharge electrode 1. Here, discharge electrode 1 is located on the negative (grounded) side, therefore the corona discharge generated at the discharge portion 11 of discharge electrode 1 is a negative polarity corona. At this time, a region A1 of insulation breakdown may be locally generated around the discharge portion 11 of discharge electrode 1. This region A1 is not, like the first insulation breakdown region A3 and the second insulation breakdown region A4 described later in the context of localized breakdown discharge, which are each elongated in a specific direction, but rather a point (or spherical) shape.

[0130] Here, if the current capacity that the power source (external voltage circuit 4) can release between a pair of electrodes per unit time is sufficiently large, then once a discharge path is formed, it will be maintained without interruption, and will develop from corona discharge to glow discharge or arc discharge as described above.

[0131] Next, refer to Figure 9B This indicates a complete circuit breakdown discharge.

[0132] like Figure 9B As shown, a full-circuit breakdown discharge is a discharge pattern in which intermittent and repeated corona discharges develop until a full-circuit breakdown occurs between a pair of electrodes (discharge electrode 1 and counter electrode 2). In other words, for a full-circuit breakdown discharge, a discharge path L1 is created between discharge electrode 1 and counter electrode 2, where the entire structure of discharge electrode 1 and counter electrode 2 is insulated and broken down. At this time, a region A2, where the entire structure is insulated and broken down, is created between the discharge portion 11 of discharge electrode 1 and the counter electrode 2 (the corner 222 of any protruding electrode portion 22). This region A2 is not locally generated as in the first insulation breakdown region A3 and the second insulation breakdown region A4 described later in the context of partial breakdown discharge; rather, it is generated in a manner that connects the discharge portion 11 of discharge electrode 1 and the counter electrode 2.

[0133] The term "insulation breakdown" as used in this disclosure refers to the breakdown of the insulating properties of the insulator (including gases) that separates conductors, thus preventing it from maintaining an insulating state. For example, ionized molecules accelerate under the influence of an electric field and collide with other gas molecules, causing those other gas molecules to ionize. This leads to a sharp increase in ion concentration and gas discharge, resulting in insulation breakdown of the gas.

[0134] Furthermore, a full-circuit breakdown discharge, although accompanied by insulation breakdown between a pair of electrodes (discharge electrode 1 and counter electrode 2), is an intermittent discharge that does not occur continuously. Therefore, the discharge current generated between the pair of electrodes (discharge electrode 1 and counter electrode 2) is also intermittent. That is, if the power supply (external voltage circuit 4) does not have the current capacity required to maintain the discharge path L1 as described above, the voltage applied between the electrodes drops as soon as the corona discharge develops into a full-circuit breakdown, thus interrupting the discharge path L1 and stopping the discharge. Here, "current capacity" refers to the capacity of the current that can be discharged per unit time. Through repeated occurrences and cessation of such discharges, the discharge current flows intermittently. Thus, the full-circuit breakdown discharge differs from glow discharge and arc discharge, which occur continuously (i.e., the discharge current is continuously generated), in that it repeatedly experiences high and low discharge energy states.

[0135] Next, refer to Figure 9C This indicates a localized breakdown discharge.

[0136] During partial breakdown discharge, the discharge device 10 first causes a localized corona discharge at the discharge portion 11 of the discharge electrode 1. In this embodiment, the discharge electrode 1 is located on the negative (grounded) side, therefore the corona discharge generated at the discharge portion 11 of the discharge electrode 1 is a negative polarity corona. The discharge device 10 further develops the corona discharge generated at the discharge portion 11 of the discharge electrode 1 into a high-energy discharge. This high-energy discharge forms a discharge path L1 between the discharge electrode 1 and the counter electrode 2 that is partially insulated.

[0137] Furthermore, partial breakdown discharge, although accompanied by partial insulation breakdown between a pair of electrodes (discharge electrode 1 and counter electrode 2), is an intermittent discharge that does not occur continuously. Therefore, the discharge current generated between the pair of electrodes (discharge electrode 1 and counter electrode 2) is also intermittent. That is, if the power supply (external voltage circuit 4) does not have the current capacity required to maintain the discharge path L1, the voltage applied between the electrodes drops as soon as the discharge develops from corona discharge to partial breakdown discharge, thus interrupting the discharge path L1 and stopping the discharge. Through repeated occurrences and cessation of such discharges, the discharge current flows intermittently. Thus, partial breakdown discharge differs from glow discharge and arc discharge, which occur continuously (i.e., the discharge current is continuously generated), in that it repeatedly experiences high and low discharge energy states.

[0138] More specifically, the discharge device 10 generates a discharge between the discharge electrode 1 and the counter electrode 2 by applying an external voltage V1 between the discharge electrode 1 and the counter electrode 2, which are arranged opposite each other with a gap between them. Furthermore, during the discharge, a discharge path L1, partially broken down by insulation, is formed between the discharge electrode 1 and the counter electrode 2. Figure 9C As shown, the discharge path L1 formed at this time includes a first insulation breakdown region A3 generated around the discharge electrode 1 and a second insulation breakdown region A4 generated around the counter electrode 2.

[0139] That is, a discharge path L1 is formed between the discharge electrode 1 and the counter electrode 2, in which the insulation is not completely broken down but only partially (locally) broken down. Thus, for partial breakdown discharge, the discharge path L1 formed between the discharge electrode 1 and the counter electrode 2 is a path that has not achieved full breakdown but is partially broken down.

[0140] Here, the first insulation breakdown region A3 and the second insulation breakdown region A4 exist separately without contacting each other. In other words, the discharge path L1 includes at least one unbroken area (insulated region) between the first insulation breakdown region A3 and the second insulation breakdown region A4. Therefore, for partial breakdown discharge, in the space between the discharge electrode 1 and the counter electrode 2, a discharge current flows through the discharge path L1 in a state where partial insulation breakdown has not been achieved. In short, even if the discharge path L1 has partial insulation breakdown, that is, even if the discharge path L1 is partially unbroken, a discharge current flows through the discharge path L1 between the discharge electrode 1 and the counter electrode 2, resulting in a discharge.

[0141] Here, the second insulation breakdown region A4 is basically generated around the part of the counter electrode 2 where the distance (spatial distance) to the discharge section 11 is shortest. In this embodiment, at the corner 222 of the protruding electrode section 22, the distance D2 from the counter electrode 2 to the discharge section 11 (refer to...) Figure 1B The shortest distance is 222, thus creating a second insulation breakdown region A4 around the corner 222. That is, Figure 9C The protruding electrode portion 22 shown is actually equivalent to the corner portion 222.

[0142] Furthermore, regarding full-circuit breakdown discharge (refer to...) Figure 9B ) or partial breakdown discharge (refer to Figure 9C In comparison to corona discharge (refer to...) Figure 9AThe higher energy generated during a corona discharge produces 2 to 20 times more free radicals than a corona discharge. These free radicals are not limited to sterilization, deodorization, humidification, preservation, and virus deactivation, but also have useful effects in various situations. Ozone is also produced during the generation of free radicals through total or partial breakdown discharges. However, for total or partial breakdown discharges, the amount of free radicals generated is 2 to 20 times greater than that of corona discharges, and the amount of ozone produced is suppressed to the same level as in the case of corona discharge.

[0143] In addition, regarding localized breakdown discharge (refer to...) Figure 9C In comparison to full-circuit breakdown discharge (refer to...), Figure 9B Compared to full-circuit breakdown discharge, partial breakdown discharge can suppress the loss of free radicals caused by excessive energy, thus improving the efficiency of free radical generation. Specifically, in full-circuit breakdown discharge, the discharge energy is too high, causing some of the generated free radicals to disappear, potentially leading to a decrease in the generation efficiency of effective components. In contrast, partial breakdown discharge, compared to full-circuit breakdown discharge, has a lower discharge energy, thereby reducing the amount of free radicals lost due to exposure to excessive energy and improving the efficiency of free radical generation.

[0144] Furthermore, for partial breakdown discharge, the concentration of the electric field is alleviated compared to full-circuit breakdown discharge. Therefore, in a full-circuit breakdown discharge, a large discharge current instantaneously flows between discharge electrode 1 and counter electrode 2 through the fully broken-down discharge path, resulting in very low resistance. In contrast, for partial breakdown discharge, the concentration of the electric field is alleviated, thus suppressing the maximum instantaneous current flowing between discharge electrode 1 and counter electrode 2 when a partially broken-down discharge path L1 is formed to a value smaller than that in a full-circuit breakdown discharge. Therefore, for partial breakdown discharge, compared to a full-circuit breakdown discharge, the generation of nitrogen oxides (NOx) can be suppressed, further reducing electrical noise.

[0145] Furthermore, in this embodiment, as described above, the counter electrode 2 has a plurality of (here, four) protruding electrode portions 22, and the distance D2 from each protruding electrode portion 22 to the discharge electrode 1 (refer to...) Figure 1B The number of protruding electrode portions 22 is equal for all of them. Therefore, the insulation breakdown region A2 or the second insulation breakdown region A4 is generated around the corner 222 of one of the protruding electrode portions 22. Here, the protruding electrode portion 22 in which the insulation breakdown region A2 or the second insulation breakdown region A4 is generated is not limited to a specific protruding electrode portion 22, but is randomly determined among the multiple protruding electrode portions 22.

[0146] (2.5) Vibration frequency of the liquid

[0147] Next, the principle of increasing the vibration frequency of liquid 50 will be explained.

[0148] In this embodiment, the liquid 50 held in the discharge section 11 of the discharge electrode 1, as described above, is subjected to a force generated by the electric field, causing it to expand and contract along the central axis P1 (i.e., along the Z-axis) of the discharge electrode 1. Furthermore, even when the liquid 50 is in a contracted state, a deflection is applied to the liquid 50 in a direction that attracts it towards the peripheral electrode section 21, thereby suppressing the deformation of the liquid 50 caused by mechanical vibration to a smaller extent. Therefore, the discharge device 10 of this embodiment can increase the vibration frequency of the liquid 50, thereby improving the efficiency of generating the effective component.

[0149] That is, the peripheral electrode portion 21 and the protruding electrode portion 22 of the counter electrode 2, which exert an electric field between themselves and the liquid 50, are always located on the positive side of the Z-axis when viewed from the liquid 50, and can always exert a force on the liquid 50 that attracts it towards the positive Z-axis. Thus, according to the discharge device 10, in the direction along the central axis P1 of the discharge electrode 1 (i.e., the Z-axis direction), a bias that attracts the liquid 50 towards the counter electrode 2 can always be applied to the liquid 50. Therefore, according to the discharge device 10, the amount of deformation of the liquid 50 caused by mechanical vibration of the liquid 50 can be suppressed to a small extent, and as a result, the vibration frequency of the liquid 50 can be increased, thereby improving the generation efficiency of the effective component.

[0150] Furthermore, in the discharge device 10 of this embodiment, the voltage application circuit 4 varies the applied voltage V1 at a driving frequency corresponding to the natural vibration frequency of the liquid 50. That is, as described above, the frequency of variation of the applied voltage V1, i.e., the driving frequency, is set to a value near the resonance frequency of the liquid 50, which is within a predetermined range including the resonance frequency (natural vibration frequency) of the liquid 50 held at the discharge electrode 1. As a result, the deformation of the liquid 50 is larger, and the tip (apex) of the Taylor cone generated by the liquid 50 when an electric field is applied becomes a sharper (acute-angled) shape, making it easier to generate discharge in the discharge device 10.

[0151] Furthermore, in this embodiment, the driving frequency is a frequency higher than or equal to the natural vibration frequency of the liquid 50. In summary, the discharge device 10 of this embodiment can suppress the deformation of the liquid 50 caused by the mechanical vibration of the liquid 50 to a slightly smaller extent, thereby increasing the vibration frequency of the liquid 50. Therefore, by setting the driving frequency, which is the frequency of the variation of the applied voltage V1, to a value higher than or equal to the natural vibration frequency of the liquid 50, the vibration frequency of the liquid 50 can be increased as much as possible. Specifically, it is preferable to set the driving frequency to a value higher than or equal to the center frequency within a predetermined range defined by a lower and upper limit based on the natural vibration frequency (resonance frequency) of the liquid 50. More preferably, the driving frequency is set to be near the upper limit of the predetermined range. Thus, by applying a deflection to the liquid 50 in a direction that attracts the liquid 50 towards the peripheral electrode portion 21, the deformation of the liquid 50 caused by the mechanical vibration of the liquid 50 can be suppressed to a slightly smaller extent, thereby increasing the vibration frequency of the liquid 50. As a result, in the discharge device 10 of this embodiment, the vibration frequency of the liquid 50 can be increased, and the generation efficiency of the effective components can be improved.

[0152] (3) Variations

[0153] Embodiment 1 is merely one of the various embodiments of this disclosure. Embodiment 1 can be modified in many ways depending on the design, etc., as long as it achieves the purpose of this disclosure. Furthermore, the figures referenced in this disclosure are schematic, and the size and thickness ratios of the constituent elements in the figures may not necessarily reflect the actual size ratios. Hereinafter, variations of Embodiment 1 are listed. The variations described below can be appropriately combined and applied.

[0154] The counter electrode 2 may also have an appropriate number of protruding electrode portions 22, and is not limited to four. For example, the counter electrode 2 may also have an odd number of protruding electrode portions 22. The number of protruding electrode portions 22 of the counter electrode 2 is not limited to four, and may be one, two, three, or five or more. Furthermore, it is not necessary to arrange multiple protruding electrode portions 22 at equal intervals in the circumferential direction of the opening 23; the multiple protruding electrode portions 22 may also be arranged at appropriate intervals in the circumferential direction of the opening 23.

[0155] Alternatively, the liquid supply unit 5 for generating charged microparticle liquid may be omitted from the discharge device 10. In this case, the discharge device 10 generates air ions by generating a discharge (full-circuit breakdown discharge or partial breakdown discharge) between the discharge electrode 1 and the counter electrode 2.

[0156] Furthermore, the liquid supply unit 5 is not limited to a structure that cools the discharge electrode 1 and generates condensation on the discharge electrode 1 as in Embodiment 1. The liquid supply unit 5 may also be a structure that uses a capillary effect or a pump to supply liquid 50 from a tank to the discharge electrode 1. In addition, the liquid 50 is not limited to water (including condensation), and may be a liquid other than water.

[0157] Alternatively, the voltage application circuit 4 can be configured such that discharge electrode 1 is the positive terminal and the counter electrode 2 is the negative terminal (grounded), applying a high voltage between discharge electrode 1 and counter electrode 2. Furthermore, since generating a potential difference (voltage) between discharge electrode 1 and counter electrode 2 is sufficient, the voltage application circuit 4 can also ground the electrode on the high potential side and ground the electrode on the low potential side, thereby applying a negative voltage to the electrode device 3. That is, the voltage application circuit 4 can also ground discharge electrode 1 and ground counter electrode 2, or vice versa.

[0158] Alternatively, a limiting resistor R1 can be inserted between the voltage generating circuit 41 and the discharge electrode 1. In this case, since the discharge electrode 1 becomes the negative terminal (grounded), the limiting resistor R1 is inserted between the low-potential output terminal of the voltage generating circuit 41 and the electrode device 3. Alternatively, if the discharge electrode 1 is set as the positive terminal and the opposing electrode 2 is set as the negative terminal (grounded), the limiting resistor R1 can be inserted between the high-potential or low-potential output terminal of the voltage generating circuit 41 and the electrode device 3. Furthermore, the limiting resistor R1 is not a necessary component and can be omitted appropriately.

[0159] Furthermore, the discharge electrode 1 and the counter electrode 2 are not limited to titanium alloys (Ti alloys); as an example, they can also be copper alloys such as copper-tungsten alloys (Cu-W alloys). Additionally, the discharge electrode 1 is not limited to a thin-tipped shape; for example, it can also be a bulging-tipped shape.

[0160] Furthermore, the high voltage applied to the electrode device 3 from the voltage external circuit 4 is not limited to about 6.0kV. For example, it can be appropriately set according to the shape of the discharge electrode 1 and the counter electrode 2 or the distance between the discharge electrode 1 and the counter electrode 2.

[0161] Furthermore, the same functions as those of the voltage applied circuit 4 in Embodiment 1 can also be implemented using the control method of the voltage applied circuit 4, a computer program, or a storage medium storing a computer program. That is, the functions corresponding to the control circuit 43 can also be implemented using the control method of the voltage applied circuit 4, a computer program, or a storage medium storing a computer program.

[0162] Furthermore, when comparing two values, the term "above" includes both cases where the two values ​​are equal and cases where one value exceeds the other. However, this disclosure is not limited to this; "above" can also be synonymous with "greater than," which only includes cases where one value exceeds the other. In other words, whether the case of equal values ​​is included can be arbitrarily changed depending on the setting of thresholds, etc., so there is no technical difference between "above" and "greater than." Similarly, "less than" can also be synonymous with "below."

[0163] (Implementation Method 2)

[0164] The discharge device 10 of this embodiment is as follows: Figures 10A to 10D As shown, the shapes of the counter electrodes 2A to 2D differ from those of the discharge device 10 in Embodiment 1. Hereinafter, common reference numerals will be used for structures identical to those in Embodiment 1, and descriptions will be omitted where appropriate. Figures 10A to 10D This is a schematic top view showing the counter electrodes 2A to 2D of Embodiment 2.

[0165] Figure 10A The counter electrode 2A shown is configured such that multiple (here, two) protruding electrode portions 22 are arranged along the Y-axis direction. Figure 10A In the example, when viewed from one side of the central axis P1 of the discharge electrode 1, i.e., when viewed from above, the protruding electrode portion 22 is triangular in shape. The term "triangular shape" as used in this disclosure is not limited to a triangle with three vertices, but also includes triangles such as... Figure 10A As shown in the diagram, the protruding electrode portion 22 has a top surface with an R-shaped (curved) top.

[0166] Figure 10B The counter electrode 2B shown has four triangular protruding electrode portions 22 when viewed from above. Figure 10B In this configuration, with the positive direction of the X-axis (to the right) defined as "0 degrees" and the positive direction of the Y-axis (above) defined as "90 degrees", the four protruding electrode portions 22 are respectively positioned at 0 degrees, 90 degrees, 180 degrees, and 270 degrees.

[0167] Figure 10C The counter electrode 2C shown has four triangular protruding electrode portions 22 when viewed from above. Figure 10C In this configuration, with the positive direction of the X-axis (to the right) defined as "0 degrees" and the positive direction of the Y-axis (above) defined as "90 degrees", the four protruding electrode portions 22 are respectively positioned at 45 degrees, 135 degrees, 225 degrees, and 315 degrees.

[0168] exist Figure 10DIn the counter electrode 2D shown, the peripheral electrode portion 21 and the protruding electrode portion 22 are independent of each other. In this case, when viewed from one side of the central axis P1 of the discharge electrode 1, the protruding electrode portion 22 also protrudes from a portion of the peripheral electrode portion 21 in the circumferential direction toward the central axis P1 of the discharge electrode 1. In this case, the protruding electrode portion 22 is fixed to the peripheral electrode portion 21 by a suitable joining method (welding, thread fixing, riveting, etc.).

[0169] In addition, in this embodiment, the extension portion 25 extending outward from the peripheral electrode portion 21 is omitted, but it is not limited to this structure. The counter electrodes 2A to 2D may also have the extension portion 25.

[0170] And, not limited to Figures 10A to 10D For example, the discharge electrode 1 and the counter electrode 2 in the electrode device 3 can adopt appropriate shapes. As an example, the peripheral electrode portion 21 of the counter electrode 2 can adopt an appropriate shape, such as a circle, ellipse, triangle, quadrilateral, or other polygon, when viewed from above. The outer diameter, inner diameter, and thickness of the peripheral electrode portion 21 can be any value. Similarly, the protruding electrode portion 22 of the counter electrode 2 can adopt an appropriate shape, such as a needle-like, triangular, quadrilateral, or other polygon, when viewed from above. The protrusion amount, width, and thickness of the protruding electrode portion 22 can be any value.

[0171] The various structures (including variations) described in Embodiment 2 can be appropriately combined with the various structures (including variations) described in Embodiment 1.

[0172] (Summarize)

[0173] As explained above, the discharge device (10) of the first type has a discharge electrode (1), opposing electrodes (2, 2A to 2D), an applied voltage circuit (4), and a liquid supply unit (5). The discharge electrode (1) is a cylindrical electrode. The opposing electrodes (2, 2A to 2D) are opposite to the discharge electrode (1). The applied voltage circuit (4) generates a discharge by applying an applied voltage (V1) between the discharge electrode (1) and the opposing electrodes (2, 2A to 2D). The liquid supply unit (5) supplies liquid (50) to the discharge electrode (1). The liquid (50) expands and contracts along the central axis (P1) of the discharge electrode (1) due to the discharge. The opposing electrodes (2, 2A to 2D) have a peripheral electrode portion (21) and a protruding electrode portion (22). The peripheral electrode portion (21) protrudes to the side opposite to the discharge electrode (1) and has an opening (23) formed on its top surface. The protruding electrode portion (22) protrudes from the peripheral electrode portion (21) into the opening portion (23). In the direction along the central axis (P1) of the discharge electrode (1), the tip of the liquid (50) in the elongated state is located at the same position as the outer periphery (210) of the peripheral electrode portion (21) or at a position closer to the discharge electrode (1) than the outer periphery (210).

[0174] According to this method, since the peripheral electrode portion (21) protrudes to the side opposite to the discharge electrode (1) and has an opening (23) formed on its top surface, the liquid (50) held on the discharge electrode (1) is subjected to an electric field that attracts the liquid towards the peripheral electrode portion (21). Moreover, in the direction along the central axis (P1) of the discharge electrode (1), the top of the liquid (50) in its elongated state is located at the same position as the outer periphery (210) of the peripheral electrode portion (21) or closer to the discharge electrode (1) than the outer periphery (210). As a result, when the liquid (50) held on the discharge electrode (1) undergoes mechanical vibration, for example, a force is continuously applied to the liquid (50) in the direction of attracting the peripheral electrode portion (21), thereby suppressing the amplitude of the liquid (50) to a small size. That is, the deformation of the liquid (50) caused by the mechanical vibration of the liquid (50) can be suppressed to a small extent, and as a result, the vibration frequency of the liquid (50) can be increased, thereby improving the generation efficiency of the effective components.

[0175] According to the first method, in the discharge device (10) of the second method, when viewed from one side of the central axis (P1) of the discharge electrode (1), the protruding electrode part (22) is arc-shaped.

[0176] According to this method, the concentration of electric field at the protruding electrode part (22) can be mitigated.

[0177] According to the first or second method, in the discharge device (10) of the third method, the counter electrode (2, 2A to 2D) has three or more protruding electrode portions (22).

[0178] According to this method, discharges can be generated in a dispersed manner on more than three protruding electrode portions (22).

[0179] According to any one of the first to third methods, in the discharge device (10) of the fourth method, the distance (D4, D6) from the liquid (50) to the protruding electrode (22) is less than or equal to the distance (D3, D5) from the liquid (50) to the peripheral electrode (21).

[0180] According to this method, the electric field is easily concentrated between the liquid (50) and the protruding electrode (22), and discharge is easily generated between the liquid (50) and the counter electrode (2, 2A~2D).

[0181] According to the fourth method, in the discharge device (10) of the fifth method, the distance (D4, D6) from the liquid (50) to the protruding electrode (22) is 9 / 10 or less of the distance (D3, D5) from the liquid (50) to the peripheral electrode (21).

[0182] According to this method, the electric field is easily concentrated between the liquid (50) and the protruding electrode (22), and discharge is easily generated between the liquid (50) and the counter electrode (2, 2A~2D).

[0183] According to any one of the first to fifth embodiments, in the discharge device (10) of the sixth embodiment, the inclination angle (θ1, θ2) of the imaginary line connecting the liquid (50) and the top of the protruding electrode (22) relative to the central axis (P1) of the discharge electrode (1) in the imaginary plane (VP1) is 67 degrees or less. The imaginary plane (VP1) includes the central axis (P1) of the discharge electrode (1) and the top of the protruding electrode (22).

[0184] According to this method, the electric field is easily concentrated between the liquid (50) and the protruding electrode (22). In particular, the force that attracts the liquid (50) to the opposing electrode (2, 2A-2D) is easily applied to the liquid (50) along the central axis (P1) of the discharge electrode (1).

[0185] According to any one of the first to sixth embodiments, in the discharge device (10) of the seventh embodiment, the counter electrode (2, 2A to 2D) further has an extension portion (25) extending outward from the peripheral electrode portion (21). The extension portion (25) is formed such that the further away from the peripheral electrode portion (21) it is from the discharge electrode (1) in the direction along the central axis (P1) of the discharge electrode (1).

[0186] According to this method, it is possible to avoid excessive electric field concentration on the outside of the peripheral electrode section (21), and to easily generate an appropriate electric field that is conducive to discharge.

[0187] According to any one of the first to seventh embodiments, in the discharge device (10) of the eighth embodiment, at least one of the following four portions of the opposing electrode (2, 2A to 2D) includes a curved shape. The first portion is the top surface (221) of the protruding electrode portion (22) when viewed from one side of the central axis (P1) of the discharge electrode (1). The second portion is the corner (222) of the protruding electrode portion (22) on the side of the discharge electrode (1) within an imaginary plane (VP1) encompassing the central axis (P1) of the discharge electrode (1) and the top surface of the protruding electrode portion (22). The third portion is the corner (211) of the peripheral electrode portion (21) on the side of the discharge electrode (1) within an imaginary plane (VP1) encompassing the central axis (P1) of the discharge electrode (1) and the top surface of the protruding electrode portion (22). The fourth part is the inner surface (212) of the peripheral electrode part (21) within the imaginary plane (VP1) containing the central axis (P1) of the discharge electrode (1) and the top of the protruding electrode part (22).

[0188] This method avoids excessive concentration of the electric field and makes it easier to generate a suitable electric field that facilitates discharge.

[0189] According to the eighth method, in the discharge device (10) of the ninth method, the radius of curvature of the curved shape of the top surface (221) of the protruding electrode portion (22) is larger than the radius of curvature of the curved shape of the corner portion (222) of the protruding electrode portion (22) on the side near the discharge electrode (1).

[0190] According to this method, excessive electric field concentration on the top surface (221) of the protruding electrode portion (22) can be avoided, and an appropriate electric field conducive to discharge can be easily generated.

[0191] According to the eighth or ninth method, in the discharge device (10) of the tenth method, the radius of curvature of the curved shape of the top surface (221) of the protruding electrode portion (22) is smaller than the radius of curvature of the curved shape of the inner surface (212) of the peripheral electrode portion (21).

[0192] According to this method, excessive electric field concentration on the inner surface (212) of the peripheral electrode section (21) can be avoided, and a suitable electric field that is conducive to discharge can be easily generated.

[0193] According to any one of the first to tenth methods, in the discharge device (10) of the eleventh method, the voltage applied circuit (4) causes the applied voltage (V1) to vary at a driving frequency corresponding to the natural vibration frequency of the liquid (50).

[0194] According to this method, variations in the applied voltage (V1) can easily and efficiently contribute to the mechanical vibration of the liquid (50).

[0195] According to the 11th method, in the discharge device (10) of the 12th method, the driving frequency is a frequency higher than or equal to the natural vibration frequency of the liquid (50).

[0196] According to this method, the vibration frequency of the liquid (50) can be increased, thereby improving the efficiency of generating effective components.

[0197] The electrode device of the 13th type is the electrode device used in the discharge device (10) of any of the 1st to 12th types, having a discharge electrode (1) and a counter electrode (2, 2A to 2D), and being subjected to an applied voltage (V1) from the applied voltage circuit (4).

[0198] This method can improve the efficiency of generating effective components.

[0199] The discharge device (10) of the 14th type has a discharge electrode (1), a counter electrode (2, 2A to 2D), and a voltage external circuit (4). The discharge electrode (1) is a columnar electrode. The counter electrodes (2, 2A to 2D) are opposite to the discharge electrode (1). The voltage external circuit (4) generates discharge by applying an external voltage (V1) between the discharge electrode (1) and the counter electrodes (2, 2A to 2D). The counter electrodes (2, 2A to 2D) have a peripheral electrode portion (21) and a protruding electrode portion (22). The peripheral electrode portion (21) protrudes to the side opposite to the discharge electrode (1) and has an opening (23) formed on its top surface. The protruding electrode portion (22) protrudes from the peripheral electrode portion (21) into the opening (23). Along the direction of the central axis (P1) of the discharge electrode (1), the top of the discharge electrode (1) is located on the side closer to the discharge electrode (1) than the outer periphery (210) of the peripheral electrode portion (21).

[0200] This method can improve the efficiency of generating effective components.

[0201] The structures of methods 2 to 12 are not necessary for the discharge device (10) and can be appropriately omitted.

[0202] The discharge device and electrode device can be applied to a variety of applications, including refrigerators, washing machines, hair dryers, air conditioners, fans, air purifiers, humidifiers, beauty devices, and automobiles.

[0203] Explanation of reference numerals in the attached figures

[0204] 1. Discharge electrode; 2. 2A~2D, Opposite electrode; 4. Voltage applied circuit; 5. Liquid supply section; 10. Discharge device; 21. Peripheral electrode section; 22. Protruding electrode section; 23. Opening; 25. Extension section; 50. Liquid; 210. Outer periphery; 211. Corner; 212. Inner surface; 221. Top surface; 222. Corner; D3~D6, Distance; V1, Applied voltage; VP1, Imaginary plane.

Claims

1. A discharge device, wherein, The discharge device has the following features: The discharge electrode is cylindrical. A counter electrode, which is opposite to the discharge electrode; An external voltage circuit generates discharge by applying an external voltage between the discharge electrode and the counter electrode; as well as The liquid supply unit supplies liquid to the discharge electrode. The liquid expands and contracts along the central axis of the discharge electrode due to the discharge. The counter electrode has: The peripheral electrode portion protrudes to the side opposite to the discharge electrode and has an opening formed on its top surface; and The protruding electrode portion, when viewed from one side of the central axis of the discharge electrode, protrudes from a portion of the peripheral electrode portion circumferentially toward the central axis of the discharge electrode and into the opening in a direction orthogonal to the central axis. The peripheral electrode portion is formed into a flat hemispherical shell shape.

2. The discharge device according to claim 1, wherein, When viewed from one side of the central axis of the discharge electrode, the outer periphery of the protruding electrode portion is generally arc-shaped.

3. The discharge device according to claim 1 or 2, wherein, The distance from the liquid to the protruding electrode portion is less than or equal to the distance from the liquid to the peripheral electrode portion.

4. The discharge device according to claim 3, wherein, The distance from the liquid to the protruding electrode is less than 9 / 10 of the distance from the liquid to the peripheral electrode.

5. The discharge device according to claim 1 or 2, wherein, In the opposing electrode, at least one of the following four components—the top surface of the protruding electrode portion when viewed from one side of the central axis of the discharge electrode, the corner of the protruding electrode portion on the discharge electrode side within an imaginary plane containing the central axis of the discharge electrode and the top surface of the protruding electrode portion, the corner of the peripheral electrode portion on the discharge electrode side, and the inner surface of the peripheral electrode portion—has a curved shape.

6. The discharge device according to claim 5, wherein, The radius of curvature of the curved shape of the top surface of the protruding electrode is larger than the radius of curvature of the curved shape of the corner of the protruding electrode on the side of the discharge electrode.

7. The discharge device according to claim 5, wherein, The radius of curvature of the curved shape of the top surface of the protruding electrode is smaller than the radius of curvature of the curved shape of the inner surface of the peripheral electrode.

8. The discharge device according to claim 6, wherein, The radius of curvature of the curved shape of the top surface of the protruding electrode is smaller than the radius of curvature of the curved shape of the inner surface of the peripheral electrode.

9. The discharge device according to claim 1 or 2, wherein, The applied voltage circuit uses a driving frequency corresponding to the natural vibration frequency of the liquid to vary the applied voltage.

10. The discharge device according to claim 9, wherein, The driving frequency is a frequency higher than or equal to the natural vibration frequency of the liquid.

11. The discharge device according to claim 1 or 2, wherein, Along the central axis of the discharge electrode, the top of the discharge electrode is located closer to the discharge electrode side than the outer periphery of the peripheral electrode portion.

Images