Ion generator

In an ion generator, a high-voltage electrode with a contact portion is disposed on a first main surface of an insulating substrate and is connected to a wire electrode, and a ground electrode covered with an insulating film is disposed on a second main surface of the insulating substrate. The ground electrode is electrically connected to a contact portion on the first main surface via a through hole. By disposing the high-voltage electrode and the ground electrode on different surfaces, the occurrence of an undesirable leakage current flowing from the high-voltage electrode to the ground electrode is prevented.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to ion generators, and, more particularly, to an ion generator used in an air cleaner or an air conditioner.

2. Description of the Related Art

In recent years, for environmental improvement, various ion generators have been provided. For example, an ion generator disclosed in Japanese Unexamined Patent Application Publication No. 2005-63827 is known. As illustrated inFIG. 8, in this ion generator, a ground electrode142covered with an insulating film144is disposed on a substrate141, and a wire electrode145is disposed between two legs142aand142bof the ground electrode142. The wire electrode145is connected to a high-voltage electrode143disposed on the substrate141. When a high-tension current is supplied to the wire electrode145, a leakage current flows from the wire electrode145to the ground electrode142, so that ions are generated.

In this ion generator, however, the ground electrode142and the high-voltage electrode143are close to each other since they are disposed on the same surface. As a result, an undesirable leakage current flows from the high-voltage electrode143to the ground electrode142. This reduces the number of ions generated.

SUMMARY OF THE INVENTION

To overcome the problems described above, preferred embodiments of the present invention provide an ion generator capable of stabilizing the number of ions generated by preventing the occurrence of an undesirable leakage current flowing from a high-voltage electrode to a ground electrode.

An ion generator according to a preferred embodiment of the present invention includes an insulating substrate, a ground electrode with a contact portion which is provided on the insulating substrate, an insulating film covering the ground electrode which is disposed on the insulating substrate, a high-voltage electrode including a contact portion which is disposed on the insulating substrate, and a wire electrode attached to the high-voltage electrode and arranged to face the ground electrode. The high-voltage electrode and the ground electrode are disposed on different surfaces of the insulating substrate.

In an ion generator according to this preferred embodiment of the present invention, the high-voltage electrode and the ground electrode are disposed on different surfaces of the insulating substrate. Accordingly, the distance between the high-voltage electrode and the ground electrode is increased, and the occurrence of an undesirable leakage current flowing from the high-voltage electrode to the ground electrode is prevented. As a result, the number of ions generated can be stabilized without reduction.

In an ion generator according to this preferred embodiment of the present invention, a through hole is preferably provided at the insulating substrate and one of the contact portions of the high-voltage electrode and the ground electrode preferably extends on the same surface as the other one of the contact portions of the high-voltage electrode and the ground electrode through the through hole. Since the contact portions of the high-voltage electrode and the ground electrode, which are disposed on different surfaces, can be provided on the same surface, each of the contact portions can be easily connected to a lead wire and the size of the ion generator can be reduced.

A plurality of wire electrodes may be provided. By providing a plurality of wire electrodes, ions can be generated in a plurality of directions over a wide area. Since the high-voltage electrode and the ground electrode are disposed on different surfaces even when a plurality of wire electrodes are provided, it is not necessary to provide a plurality of contact portions of each of the high-voltage electrode and the ground electrode. Furthermore, it is not necessary to increase the number of lead wires.

A plurality of wire electrodes may be individually disposed at opposite end portions of the insulating substrate. In this case, it is desirable that the ground electrode have a substantially X-shaped pattern. By configuring the ground electrode to have a substantially X-shaped pattern, the patterns of the ground electrode42can be collectively arranged in the approximate center of the insulating substrate, it is not necessary to provide a plurality of contact portions, and the distance between the ground electrode and the high-voltage electrode disposed on a surface different from the surface on which the ground electrode is disposed is increased. This prevents the occurrence of an undesirable leakage current.

A leading end portion of the ground electrode facing a leading end of the wire electrode may not be covered with the insulating film. In this case, the amount of leakage current flowing from the wire electrode to the ground electrode is increased, so that ions and a small amount of ozone are generated. The generation of ozone increases a deodorant effect and an antibacterial effect. In this case, the ground electrode is preferably a resistor. When the ground electrode is a resistor, the amount of ozone generated can be easily controlled by changing the resistance of the resistor.

A cutout may be provided at one side of the insulating substrate, the leading end of the wire electrode may be arranged in the cutout, and legs of the ground electrode may extend in a direction substantially parallel to the wire electrode sandwiched between the legs on opposite sides of the cutout on the insulating substrate. The wire electrode and the ground electrode may be two-dimensionally arranged, and the thickness of an ion generator can be reduced accordingly.

An ion generator preferably further includes a first terminal that is connected to the contact portion of the high-voltage electrode and includes a retaining portion arranged to be connected to a lead wire, a second terminal that is connected to the contact portion of the ground electrode and includes a retaining portion arranged to be connected to another lead wire, and a case arranged to accommodate the insulating substrate, the ground electrode, the wire electrode, the high-voltage electrode, the first terminal, and the second terminal. With this configuration, a small and low-cost ion generator can be obtained. Ribs are preferably provided at an opening of the case which faces the leading end of the wire electrode. The ribs prevent a user from touching the wire electrode with a user's finger. As a result, safety is improved.

In the ion generator according to this preferred embodiment of the present invention, the distance between the high-voltage electrode and the ground electrode is increased. As a result, the occurrence of an undesirable leakage current flowing from the high-voltage electrode to the ground electrode is prevented, and the number of ions generated is stabilized without reduction.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

An ion generator according to preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

First Preferred Embodiment

FIG. 1is an exploded perspective view of an ion generator1according to a first preferred embodiment of the present invention, andFIG. 2is an external perspective view thereof. As illustrated inFIG. 1, the ion generator1preferably includes a lower resin case2, an upper resin case3, an ion-generating component4, a first terminal5A, a second terminal5B, lead wires7and8, and a high-voltage power supply (not illustrated).

The lower resin case2includes an air inlet21provided in a side wall2aat one end, an air outlet22provided in a side wall2bat the other end, and a retaining arm23on a front side wall2c.

The upper resin case3includes an air inlet (not illustrated) provided in a side wall3aat one end, an air outlet32provided in a side wall3bat the other end and two claws31on a front side wall3c. By fitting the claws31in the retaining arm23of the lower resin case2, the upper resin case3and the lower resin case2are firmly joined to define an air-permeable resin case. The ion-generating component4and the terminals5A and5B are disposed in an accommodation portion defined inside the upper resin case3and the lower resin case2.

In the ion-generating component4, as illustrated inFIGS. 3A and 3B, on the surface (a first main surface41a) of an insulating substrate41, a high-voltage electrode43having a contact portion43aand a contact portion42cof a ground electrode42, which will be described later, are formed of a conductive paste. A cutout41cis formed by cutting out a large portion of one side of the insulating substrate41. In the cutout41c, a wire electrode45is disposed. The root of the wire electrode45is soldered to the high-voltage electrode43. The wire electrode45is made of an ultrafine wire having a diameter of about 100 μm or less, for example, a piano wire, a stainless steel wire, or a titanium wire.

On the undersurface (a second main surface41b) of the insulating substrate41, the ground electrode42is formed of a conductive paste, and is covered with an insulating film44. The ground electrode42includes a pair of legs42aand42bextending substantially parallel to the wire electrode45therebetween on opposite sides of the cutout41con the second main surface41b. At one corner of the insulating substrate41, a through hole46is provided. The ground electrode42on the second main surface41bis electrically connected to the contact portion42con the first main surface41avia the through hole46.

As the material of the insulating film44, for example, silicone or glass glaze is preferably used. The ground electrode42preferably has a resistance of approximately 50 MΩ, for example, and is made of, for example, ruthenium oxide paste or carbon paste. In particular, ruthenium oxide is the preferred material because it does not cause migration even when a high electric field is applied thereto.

Each of the first terminal5A and the second terminal5B is made of a metallic material, and includes a retaining portion51and a foot portion52. The retaining portions51of the first terminal5A and the second terminal5B are fitted in holding portions33and34provided on an upper surface3dof the upper resin case3, respectively. The foot portion52of the first terminal5A is connected to the contact portion43aof the high-voltage electrode43, and the foot portion52of the second terminal5B is connected to the contact portion42cof the ground electrode42.

An end portion7aof the high-voltage lead wire7is fitted in an opening (not illustrated) provided in the front surface of the holding portion33of the upper resin case3, and a core wire71is engaged with and electrically connected to the retaining portion51of the first terminal5a. Similarly, an end portion8aof the ground lead wire8is fitted in an opening (not illustrated) provided in the front surface of the holding portion34, and a core wire81is engaged with and electrically connected to the retaining portion51of the second terminal5B.

The high-voltage lead wire7is connected to a high-voltage output terminal of the high-voltage power supply, and the ground lead wire8is connected to a ground terminal of the high-voltage power supply. While the high-voltage power supply supplies a negative direct-current voltage, it may supply an alternating-current voltage obtained by superimposing negative direct-current biases. The ion generator1is installed in, for example, an air cleaner or an air conditioner. That is, the high-voltage power supply is mounted in a power supply circuit portion of an air cleaner or other similar device, and the ion generator1is mounted in an air blow path, so that the air cleaner or other similar device blows air containing negative ions.

The ion generator1having the above-described configuration can generate negative ions at a voltage of about −1.3 kV to about −3.0 kV (typical). That is, when a negative voltage is applied to the wire electrode45, an intense electric field is produced between the wire electrode45and the ground electrode42. The air around the leading end of the wire electrode45is subjected to dielectric breakdown and is brought into a corona discharge state. At that time, molecules in the air are brought into a plasma state around the leading end of the wire electrode45, and are separated into positive ions and negative ions. The positive ions in the air are absorbed by the wire electrode45, and the negative ions remain.

When the wire electrode45has a thin leading end (has a small radius of curvature), the concentration of electrons is more easily achieved and an intense electric field is more easily produced than when it has a thick leading end. Therefore, the use of the wire electrode45having a diameter of about 100 μm or less enables negative ions to be generated even when a low voltage is applied. Since an applied voltage can be reduced, safety is improved. Furthermore, since the high-voltage electrode43and the ground electrode42are disposed on different surfaces (the first main surface41aand the second main surface41b) of the insulating substrate41, the distance therebetween is increased. This prevents the flow of an undesirable leakage current from the high-voltage electrode43to the ground electrode42. As a result, the number of ions generated can be stabilized without reduction.

Since the through hole46is provided at the insulating substrate41and the contact portion42cof the ground electrode42extends onto the first main surface41avia the through hole46along with the contact portion43aof the high-voltage electrode43, the contact portions43aand42ccan be easily connected to the lead wires7and8, respectively. This facilitates reducing the size of the ion generator1.

In the ion generator1, the insulating substrate41includes the cutout41cat one side, the leading end of the wire electrode45is disposed in the cutout41c, and the ground electrode42includes the legs42aand42bextending substantially parallel to the wire electrode45therebetween on opposite sides of the cutout41con the insulating substrate41. Accordingly, the wire electrode45and the ground electrode42can be two-dimensionally arranged. This enables a reduction in the thickness of the ion generator1.

Second Preferred Embodiment

FIGS. 4A and 4Billustrate the surface (the first main surface41a) and the undersurface (the second main surface41b) of the insulating substrate41used in an ion generator according to the second preferred embodiment of the present invention. The contact portion42cof the ground electrode42is provided on the second main surface41band is connected to the extended foot portion52of the second terminal5B without the through hole46described in the first preferred embodiment.

A leading end portion of the ground electrode42which is opposite the leading end of the wire electrode45is not covered with the insulating film44. By exposing the leading end portion of the ground electrode42, a leakage current flows between the ground electrode42and the wire electrode45. This leakage current splits an oxygen molecule O2in the air into oxygen atoms O. Each of the oxygen atoms O reacts with an oxygen molecule O2in the air to form ozone O3(O2+O→O3). As a result, an extremely small amount of ozone is generated. The amount of ozone generated can be controlled by changing the area or position of an exposed portion42d. Furthermore, the amount of ozone generated can be controlled by changing the resistance of the ground electrode42which functions as a resistor.

In the second preferred embodiment, the distance between the high-voltage electrode43and the ground electrode42can be increased since they are formed on different surfaces of the insulating substrate41. This prevents the flow of an undesirable leakage current from the high-voltage electrode43to the ground electrode42. As a result, the number of ions generated and the amount of ozone generated can be stabilized without reduction.

Except for the above-described points, the configuration and the operational effect according to the second preferred embodiment are substantially the same as those according to the first preferred embodiment.

Third Preferred Embodiment

FIGS. 5A and 5Billustrate the surface (the first main surface41a) and the undersurface (the second main surface41b) of the insulating substrate41used in an ion generator according to the third preferred embodiment of the present invention. In the third preferred embodiment, the wire electrode45is disposed at both end portions of the insulating substrate41.

More specifically, the high-voltage electrode43provided on the first main surface41aof the insulating substrate41is provided with a connection portion43bto which the roots of the two wire electrodes45are soldered, and is covered with an insulating film44′ except for the connection portion43band the contact portion43a. On the second main surface41b, the ground electrode42having an X-shaped pattern is provided. In a central portion of the X-shaped pattern, the contact portion42cis provided. The ground electrode42is covered with the insulating film44except for a leading end portion (the exposed portion42d) facing the leading end of each of the wire electrodes45and the contact portion42c.

The foot portion52of the first terminal5A is connected to the contact portion43aof the high-voltage electrode43, and the extended foot portion52of the second terminal5B is connected to the contact portion42cof the ground electrode42.

Except for the above-described points, the configuration and the operational effect according to the third preferred embodiment are substantially the same as those according to the first preferred embodiment.

In particular, by disposing the two wire electrodes45, ions and ozone can be generated in both directions over a wide area. If the high-voltage electrode43and the ground electrode42are disposed on the same surface, the shape of the high-voltage electrode43is limited due to the existence of the ground electrode42. In this case, two contact portions of the high-voltage electrode43are provided, and the two lead wires7are therefore required. However, since the high-voltage electrode43and the ground electrode42are disposed on different surfaces, the shape of the high-voltage electrode43on the first main surface41acan be freely changed, so that it is not necessary to provide a plurality of contact portions43aand a plurality of lead wires7. Similarly, it is not necessary to provide a plurality of contact portions42cof the ground electrode42and a plurality of lead wires8.

Furthermore, since the pattern of the ground electrode42is X-shaped, the patterns of the ground electrode42can be collectively arranged in the central portion of the second main surface41b. As a result, it is not necessary to provide a plurality of contact portions42c, the distance between the ground electrode42and the high-voltage electrode43can be increased, and the occurrence of an undesirable leakage current can be further prevented. Consequently, the number of ions generated and the amount of ozone generated can be stabilized without reduction. As described previously in the second preferred embodiment, by exposing the leading end portion of the ground electrode42, the amount of ozone generated can be increased.

Fourth Preferred Embodiment

FIGS. 6A and 6Billustrate the surface (the first main surface41a) and the undersurface (the second main surface41b) of the insulating substrate41used in an ion generator according to the fourth preferred embodiment of the present invention. In the fourth preferred embodiment, similar to the third preferred embodiment, the wire electrode45is disposed at both end portions of the insulating substrate41. Furthermore, the ground electrode42provided on the second main surface41bis electrically connected to the contact portion42cprovided on the first main surface41avia a through hole47provided at the insulating substrate41.

In the fourth preferred embodiment, since the contact portion42cof the ground electrode42is provided on the first main surface41aon which the high-voltage electrode43is disposed, the high-voltage electrode43is disposed on the side of one end portion of the insulating substrate41apart from the contact portion42cof the ground electrode42so as to increases the distance between the high-voltage electrode43and the contact portion42cof the ground electrode42. As a result, the occurrence of an undesirable current is prevented. By disposing the ground electrode42on the side of one end portion of the insulating substrate41opposite the other end portion at which the high-voltage electrode43is disposed so as to further increase the distance between the high-voltage electrode43and the ground electrode42, the occurrence of an undesirable leakage current is further prevented.

Except for the above-described points, the configuration and the operational effect according to the fourth preferred embodiment are substantially the same as those according to the first and third preferred embodiments.

Fifth Preferred Embodiment

FIG. 7illustrates the cases2and3of an ion generator according to the fifth preferred embodiment of the present invention. A configuration according to the fifth preferred embodiment is substantially the same as that according to the first preferred embodiment. That is, ribs25and ribs35are provided at the openings (the air outlets22and23facing the leading end of the wire electrode45, see,FIG. 1) of the cases2and3, respectively. The ribs25and35prevent a user from touching the wire electrode45with a user's finger, so that safety is improved.

An ion generator according to the present invention is not limited to an ion generator according to any one of the above-described preferred embodiments. Various changes can be made to an ion generator according to the present invention without departing from the spirit and scope of the present invention.

For example, the exposed portion42dof the ground electrode42may have any suitable shape, and may be disposed at a plurality of locations.

The present invention can be applied not only to the generation of negative ions but also to the generation of positive ions. In this case, a high-voltage power supply for generating a positive voltage is used, and a positive voltage is applied to a high-voltage electrode.

As described previously, the present invention is useful for an ion generator, and, in particular, has an advantage in its suitability for stabilizing the number of ions generated.