JP2001155842A - Ion generating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ion generating apparatus for increasing and controlling ion generating amount. SOLUTION: A silicon electrode 22 having a plurality of needles 24 with leading end diameter of not more than 1 μm is provided on one side of a single crystal silicon wafer and an electric current is passed to a coil 34, therefore a magnetic field is generated between the electrode 22 and opposed electrode 26. As concentration of the magnetic field is generated at the leading end of the needles 24, discharging can be generated with lower current and a large amount of ions can be generated. By generation of the magnetic field, ions or electrons are spirally moved along magnetic lines to lengthen its track. Therefore, collision times of ions or electrons to atoms in air are frequent so that generating amount of ions increase rapidly. Also, the generating amount of ions is controlled by varying current flowing to the coil 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion generator, and more particularly, to an ion generator that generates ions by electric discharge.

[0002]

2. Description of the Related Art Conventionally, this type of ion generator applies a high voltage to one needle-like electrode and a counter electrode facing the tip of the needle-like electrode. There has been proposed a device in which a high voltage is applied to a counter electrode arranged in parallel with a shape electrode. FIG. 7 shows an example of the former ion generating device including the needle-shaped electrodes, and FIG. 8 shows an example of the latter ion generating device including the linear electrodes. In these ion generators, the gas in the air is ionized by a discharge generated by applying a high voltage between the opposing electrodes.

[0003]

However, these ion generators have a problem that the amount of ion generation is small because the contact area between the needle electrode or the linear electrode and the air is small. To solve this problem, it is possible to increase the amount of ions by increasing the voltage between the electrodes, but in this case, a gas such as ozone is generated in addition to the ions.

An object of the ion generator of the present invention is to increase the amount of generated ions. Another object of the present invention is to control the amount of generated ions.

[0005]

Means for Solving the Problems and Their Functions and Effects The ion generator of the present invention employs the following means in order to achieve at least a part of the above objects. The ion generator of the present invention is an ion generator that generates ions by electric discharge, and is separated from a silicon electrode having a plurality of needles arranged substantially in parallel on one surface of a single crystal silicon wafer by a predetermined distance. The invention further comprises a counter electrode facing the plurality of needle-shaped portions, and voltage applying means for applying a voltage to the silicon electrode and the counter electrode.

In the ion generating apparatus of the present invention, the plurality of needles are separated by a predetermined distance from the silicon electrode having a plurality of needles arranged substantially in parallel on one surface of the single crystal silicon wafer by the voltage applying means. By applying a voltage to the counter electrode facing the shape portion, a discharge is caused to ionize the gas in the air. Since the silicon electrode has a plurality of needle-shaped portions, the contact area with the air is increased, and many ions can be generated without increasing the applied voltage. As a result, a device that generates less gas such as ozone and generates more ions can be obtained.

In the ion generator according to the present invention, the plurality of needle-shaped portions may be formed to have a tip diameter of 1 μm or less. In this case, since the electric field is concentrated and electric discharge easily occurs, ions can be generated efficiently. Further, the ion generator of the present invention may be provided with a magnetic field generating means for generating a magnetic field between the silicon electrode and the counter electrode. In this case, the amount of generated ions can be increased. Ions and electrons generated by the discharge spirally move along the lines of magnetic force, so that their trajectories become longer. This increases the chances that ions and electrons collide with molecules and atoms in the air, and further ionizes them.

In the ion generating apparatus of the present invention having such a magnetic field generating means, a current detecting means for detecting a current flowing through the counter electrode in accordance with application of a voltage by the voltage applying means, Magnetic field control means for controlling the magnetic field generation means so that the intensity of the magnetic field can be changed based on the magnetic field generation means. In this way, the amount of generated ions can be controlled.
In the ion generator according to the aspect of the present invention, the magnetic field control means controls the magnetic field generation means in a direction in which the strength of the magnetic field increases with respect to a direction in which the detected current decreases. It can also be.

Further, in the ion generating apparatus of the present invention having a magnetic field generating means, the magnetic field generating means may be a coil connected to a current source.

[0010]

Next, embodiments of the present invention will be described with reference to examples. FIG. 1 is a configuration diagram schematically showing a configuration of an ion generator 20 according to one embodiment of the present invention.
As shown in the drawing, the ion generator 20 of the embodiment includes a silicon electrode 22 having a plurality of needles 24 formed thereon and a plurality of needles 2 separated by a predetermined distance from the silicon electrode 22.
4, a voltage source 28 for applying a voltage to the silicon electrode 22 and the counter electrode 26, and a counter electrode 2
6, a coil 34 for forming a magnetic field between the silicon electrode 22 and the counter electrode 26, a current source 36 for supplying a current i2 to the coil 34, and a current flowing to the coil 34. An electronic control unit 40 for controlling the current i2.

The silicon electrode 22 is formed of a single-crystal silicon wafer.
A plurality of needle portions 24 are formed on the side facing 6. The needle-like portion 24 is formed such that the tip diameter is 1 μm or less. The silicon electrode 22 and the coil 34
Between them, a silicon oxide film 32 is formed.

The counter electrode 26 is formed of a metal such as copper. The voltage source 28 is a power supply capable of applying a voltage of 1 to several kV to the silicon electrode 22 and the counter electrode 26. In the embodiment, the voltage source 28 applies a constant voltage of, for example, 2 kV. Is configured as Current source 36
Is configured as a variable current source that allows a current set by a control signal from the electronic control unit 40 to flow through the coil 34.

The electronic control unit 40 is configured as a one-chip microprocessor mainly composed of a CPU 42, and a ROM 4 storing a processing program.
4, a RAM 46 for temporarily storing data, and an input / output port (not shown). The current i1 from the current sensor 30 is input to the electronic control unit 40 via an input port. Also, the electronic control unit 40
, A control signal to the current source 36 is output via the output port.

The ion generator 20 of the embodiment configured as described above ionizes the gas in the air by a discharge generated by applying a constant voltage from the voltage source 28 to the silicon electrode 22 and the counter electrode 26. Silicon electrode 2
2 has a plurality of needles 24 having a tip diameter of 1 μm or less, so that discharge can be started by concentrating an electric field on the tips of the needles 24 without applying a high voltage.
Moreover, by providing the plurality of needle-like portions 24, the area of contact with air can be increased and the amount of generated ions can be increased as compared with the case where the needle-like electrode is provided. Further, in the ion generator 20 of the embodiment, a magnetic field is generated between the silicon electrode 22 and the counter electrode 26 by flowing a current from the current source 36 to the coil 34, and the generated ions and electrons are generated along the magnetic field lines. Make a spiral movement. When ions or electrons are spirally moved in this manner, their trajectories are longer than in the absence of a magnetic field, so that the chances of collision with other molecules or atoms in the air are increased. Since the ions and the atoms that collide with the electrons become ions, the amount of generated ions can be increased by performing the spiral motion.

FIG. 2 shows a silicon electrode 22 and a counter electrode 26.
FIG. 4 is an explanatory diagram showing an example of a relationship between a voltage applied to a helium and an ion current. In the drawing, a curve A shows the relationship between the voltage and the ion current in the ion generator 20 of the embodiment when the current is set to a value of 0 in the coil 34, and a curve B shows the operation when a predetermined current is applied to the coil 34. The relationship between the voltage and the ion current in the ion generator 20 of the example is shown, and the curve C shows the relationship between the voltage and the ion current in the ion generator having a needle-shaped electrode as a conventional example. The scale of the axis of the ion current is an exponential scale. As can be seen from the comparison between the curves A and C, the ion generator 20 of the embodiment generates about ten times as many ions as the conventional ion generator without energizing the coil 34. Comparing the curves B and C, the ion generator 20 of the embodiment generates about 100 times as many ions as the conventional ion generator.
Further, as can be seen from the curves A and B, the ion generator 20 of the embodiment can generate ions even at a lower voltage than the conventional ion generator.

FIG. 3 is an explanatory diagram showing an example of the relationship between the current flowing through the coil 34 and the ion current when a predetermined constant voltage is applied from the voltage source 28. The axis of the ion current in the figure is an index scale. As shown in the figure, the ion generator 20 of the embodiment generates ions without passing a current through the coil 34. However, when a current is passed through the coil 34 to generate a magnetic field, the ion generation amount can be increased by 100 times or more. can do.

Next, control of the amount of generated ions in the ion generator 20 of the embodiment will be described. FIG. 4 is a flowchart illustrating an example of a current control routine executed by the electronic control unit 40 of the ion generator 20 according to the embodiment. This routine is executed every predetermined time (for example, 10 m
(every second).

When this current control routine is executed, the CPU 42 of the electronic control unit 40
A process for reading the current i1 flowing through the counter electrode 26 detected by 0 is executed (step S100). And
The read current i1 and a target current value (target current) i
* Is calculated (step S102), and a current i2 flowing through the coil 34 in a direction in which the difference Δi is canceled is calculated.
Is calculated (step S104). In the embodiment, the current i2 flowing through the coil 34 has a deviation Δi with respect to the current current i2.
Is calculated by using a proportional term acting in the direction to cancel and an integral term for eliminating the steady-state deviation. Deviation Δi
Is a direction in which the current i2 increases when the current i1 decreases, and conversely, a direction in which the current i2 decreases when the current i1 increases.

Then, the calculated current i2 to the coil 34 is calculated.
Is output to the current source 36 as a control signal (step S106), and this routine ends. The current source 36 receiving the control signal from the electronic control unit 40 operates so that the current i2 functions as a constant current source flowing through the coil 34. As a result, the amount of ions generated from the ion generator 20 of the embodiment can be made constant.

The ion generator 20 of the embodiment described above.
According to the silicon electrode 22 having a plurality of needles 24
With the use of, a large amount of ions can be generated even when a low voltage is applied. In addition, by generating a magnetic field between the silicon electrode 22 and the counter electrode 26, the amount of generated ions can be significantly increased.

According to the ion generator 20 of the embodiment, the amount of ion generation can be controlled by controlling the strength of the magnetic field based on the current i1 flowing through the counter electrode 26. For example, when it is desired to obtain a constant ion generation amount, the current i2 flowing through the coil 34 may be feedback-controlled based on the current i1 flowing through the counter electrode 26.

In the ion generator 20 of the embodiment, the voltage source 28 functions as a constant voltage source. However, the voltage source may be a variable voltage source. In this case, as shown in FIG. 2, since the amount of ion generation can be changed by changing the voltage of the voltage source 28, the amount of ion generation may be controlled by controlling the voltage of the voltage source 28.

Although the coil 34 is attached to the silicon electrode 22 in the ion generator 20 of the embodiment, a magnetic field may be generated between the silicon electrode 22 and the counter electrode 26. As shown in the generator 20B, the coil 34B may be installed at a different position and direction away from the silicon electrode 22.

In the ion generator 20 of the embodiment, a magnetic field is generated between the silicon electrode 22 and the counter electrode 26 by passing a current through the coil 34.
It is sufficient that a magnetic field is generated between the counter electrode 26 and
As shown in the ion generator 20C of the modification of FIG. 6, a magnetic field may be generated using a permanent magnet. In this case, the position of the permanent magnet may be attached to the silicon electrode 22 as illustrated in FIG. 6, or may be installed at a different position and direction away from the silicon electrode 22. In the mode using the permanent magnet as described above, the intensity of the magnetic field cannot be changed. Therefore, the amount of generated ions may be controlled by changing the voltage of the voltage source 28.

The embodiments of the present invention have been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various embodiments may be made without departing from the gist of the present invention. Of course, it can be carried out.

[Brief description of the drawings]

FIG. 1 shows an ion generator 20 according to an embodiment of the present invention.
FIG. 2 is a configuration diagram showing an outline of the configuration of FIG.

FIG. 2 is an explanatory diagram showing an example of a relationship between a voltage applied to a silicon electrode 22 and a counter electrode 26 and an ion current.

FIG. 3 is an explanatory diagram showing an example of a relationship between a current flowing through a coil and an ion current when a predetermined constant voltage is applied from a voltage source.

FIG. 4 is a flowchart illustrating an example of a current control routine executed by an electronic control unit 40 of the ion generator 20 according to the embodiment.

FIG. 5 is a configuration diagram illustrating an ion generator 20B of a modified example.

FIG. 6 is a configuration diagram illustrating an ion generator 20C of a modified example.

FIG. 7 is a configuration diagram illustrating a conventional ion generator including a needle electrode.

FIG. 8 is a configuration diagram illustrating a conventional ion generator including a linear electrode.

[Explanation of symbols]

20, 20B, 20C ion generator, 22 silicon electrode, 24 needle-like part, 26 counter electrode, 28 voltage source, 30 current sensor, 32 silicon oxide film, 34
Coil, 36 current source, 40 electronic control unit, 42
CPU, 44 ROM, 46 RAM.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideo Nakane 41-1, Okucho, Yokomichi, Nagakute-cho, Aichi-gun, Aichi F-term in Toyota Central R & D Laboratories Co., Ltd. 5C030 DD10 DE10 DG09

Claims (7)

[Claims] 1. An ion generator for generating ions by electric discharge, comprising: a silicon electrode having a plurality of needles arranged substantially in parallel on one surface of a single crystal silicon wafer; And a voltage applying means for applying a voltage to the silicon electrode and the counter electrode. 2. The ion generator according to claim 1, wherein the plurality of needle-like portions are formed in a shape having a tip diameter of 1 μm or less. 3. The ion generator according to claim 1, further comprising voltage control means for controlling said voltage applying means so as to change a voltage applied to said silicon electrode and said counter electrode. 4. The ion generator according to claim 1, further comprising a magnetic field generating means for generating a magnetic field between said silicon electrode and said counter electrode. 5. The ion generator according to claim 4, wherein current detection means detects a current flowing through the counter electrode in accordance with application of a voltage by the voltage application means, and based on the detected current. A magnetic field control unit that controls the magnetic field generation unit so that the intensity of the magnetic field can be changed. 6. The ion generator according to claim 5, wherein said magnetic field control means controls said magnetic field generation means in a direction in which said magnetic field intensity increases in a direction in which said detected current decreases. apparatus. 7. The ion generator according to claim 4, wherein said magnetic field generating means is a coil connected to a current source.