JP2011188725A - Electret, electrostatic induction-type conversion element, and method for charging electret - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an electret which can restrain charge dissipation more than before in spite of a simpler configuration and easier manufacturing, as well as a method for charging the electret that ensures easy charging of the electret. <P>SOLUTION: An electrostatic induction-type conversion element 100 includes an electret 10 having a substrate 11 made of insulating materials, a plurality of grid connection electrodes 12, a plurality of base electrodes 13, and an insulating material layer 14; a movable part 20 disposed facing the electret 10; and a resistor 30 in connection with the electret 10 and the movable part 20. All the base electrodes 13 on the electret 10 are connected with an earth and a needle electrode 41, and a grid 40 is connected with the grid connection electrodes 12 on the electret 10. Subsequently, a given voltage is applied across the needle electrode 41 and the base electrodes 13 to charge the insulating material layer 14. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electret, an electrostatic induction conversion element, and an electret charging method capable of suppressing a decrease in accumulated charge over time.

  Conventionally, electrets have been known, for example, as shown in FIG. The one shown in FIG. 3 of the following Patent Document 1 has an electret formed by injecting electric charges near the surface of an insulating material, and the electret is disposed between two conductors, The electric energy and the kinetic energy are converted by moving relative to at least one conductor facing the electret. Further, the surface of the electret is covered with a moisture-proof film so that the loss of electric charge can be prevented.

  As one of electret charging methods, for example, corona charging using an apparatus shown in FIG.

JP 2006-180450 A JP 2008-266563 A

  In recent years, there has been a demand for an electret capable of further suppressing the charge loss of the electret with a simpler configuration and a method for further easily charging the electret.

  Accordingly, an object of the present invention is to provide an electret that can suppress charge loss more than a conventional one, although it is easy to manufacture with a simpler configuration, and an electret charging method that can easily charge the electret. Is to provide.

(1) An electret according to one aspect is provided with an electrode layer in which base electrodes connectable to a power source and grid connection electrodes connectable to a grid are alternately insulated and arranged on one surface of the electrode layer And an insulating material layer provided.

(2) In the electret of the above (1), it is preferable that a separation portion (space) having a predetermined width is provided between the base electrode and the grid connection electrode.

(3) In the electret of the above (1), it is preferable that an insulating material part is provided between the base electrode and the grid connection electrode.

(4) In the electret of the above (3), it is preferable that the insulating material layer and the insulating material portion are integrally formed.

  According to the configurations of (1) to (4) above, it is possible to suppress the charge loss of the electrets as compared with the conventional one, though it is easy to produce with a simple configuration. In particular, the electret having the configuration (4) can be more easily manufactured.

(5) The electrostatic induction type conversion element according to another aspect includes any one electret among the above (1) to (4).

  According to the configuration of (5) above, the power generation efficiency can be significantly improved as compared with the conventional one.

(6) The electret charging method according to another aspect includes a grid disposing step of disposing a grid on the insulating material layer side of the electret according to any one of (1) to (4), A needle electrode disposing step of disposing a needle electrode on the opposite side of the insulating material layer side of the grid; a first connecting step of connecting a ground and the needle electrode to the base electrode of the electret; and the grid And applying a predetermined voltage between the needle electrode and the base electrode after the second connecting step for connecting the grid connecting electrode in the electret, and the first connecting step and the second connecting step. , After the charging step of charging the insulating material layer in the electret, and the first connection step and the second connection step, A voltage applying step of applying a constant voltage, but has a.

  According to the configuration of the above (6), it is possible to easily charge the electret that can suppress the disappearance of charge as compared with the conventional one.

It is the schematic block diagram which showed the electrostatic induction type conversion element which concerns on embodiment of this invention. It is the schematic for demonstrating the charging method to the electret shown in FIG. It is a graph which shows the experimental result about the electret which concerns on an Example and a comparative example. It is the schematic for demonstrating the charging method to the electret which concerns on the comparative example shown in FIG. (A) is the modification of the electret in the electrostatic induction type conversion element which concerns on embodiment of this invention, (b) is another modification.

  Hereinafter, the electrostatic induction conversion element according to the embodiment of the present invention will be described with reference to FIG.

  The electrostatic induction conversion element 100 includes an electret 10, a movable portion 20 disposed to face the electret 10, and a resistor 30 connected to the electret 10 and the movable portion 20. is there.

  The electret 10 includes a substrate 11 made of an insulating material such as glass, a plurality of grid connection electrodes 12, a plurality of base electrodes 13, and an insulating material layer 14.

  The grid connection electrode 12 and the base electrode 13 are alternately arranged on one surface of the substrate 11 to form an electrode layer 15 (having a thickness of about 100 nm to 300 nm). Examples of the material used for the grid connection electrode 12 include aluminum, copper, chromium, gold, and platinum. Examples of the material used for the base electrode 13 include aluminum, copper, chromium, gold, and platinum. The widths of the grid connection electrode 12 and the base electrode 13 are preferably the same. Since the electrode 22 in the movable portion 20 to be described later moves on the electret 10 side with and without the electric charge, the grid connection electrode 12 and the base electrode 13 have the same width. This is because the current output with respect to the displacement of the electrode 22 tends to be a clean sine wave.

  The insulating material layer 14 is laminated on one side of the electrode layer 15 and is formed so as to fill between the grid connection electrode 12 and the base electrode 13. Is insulated. The insulating material layer 14 is negatively charged. Examples of the material used for the insulating material layer 14 include Teflon polymer resin, silicon oxide film, and glass.

  The movable part 20 has a substrate 21 made of an insulating material and a plurality of electrodes 22 arranged in parallel on the surface of the substrate 21 on the electret 10 side. Moreover, the movable part 20 is arrange | positioned with the electret 10 and the predetermined space | interval to such an extent that it can carry out electrostatic induction, and can be horizontally vibrated in the arrow direction shown in FIG. Examples of the material used for the electrode 22 include aluminum, copper, chromium, gold, and platinum.

<Electret charging method>
Here, a method of charging the electret 10 will be described with reference to FIG. As shown in FIG. 2, first, the grid 40 is disposed on the insulating material layer 14 side of the electret 10 (grid disposing step). Next, the needle electrode 41 is disposed on the opposite side of the grid 40 from the insulating material layer 14 side (needle electrode disposing step). Subsequently, all the base electrodes 13 in the electret 10 are connected to the ground and the needle electrode 41 (first connection step), and the grid 40 is connected to the grid connection electrode 12 in the electret 10 (second connection step). ). Subsequently, a predetermined voltage (a voltage having a value of −6 kV to −12 kV) is applied between the needle electrode 41 and the base electrode 13. As a result, negative ions are discharged from the needle electrode 41 and are made uniform by the grid 40, and then poured onto the insulating material layer 14 to inject charges. That is, the insulating material layer 14 in the electret 10 is charged (charging process). At this time, a predetermined voltage (a voltage having a value of −300 V to −600 V) is also applied to the grid 40 (voltage application step). By performing each of these steps, the electret 10 is charged.

<Operation of electrostatic induction type conversion element>
Next, the operation of the electrostatic induction conversion element 100 will be described with reference to FIG. With the charged electret 10 fixed, the movable portion 20 is vibrated horizontally in the direction of the arrow shown in FIG. Thereby, a predetermined amount of electrical output can be obtained.

  According to the said structure, although it is easy to produce with a simple structure, the electric charge loss of the electret 10 can be suppressed rather than the conventional one. Moreover, the method with which the electret 10 is easily charged can be provided.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

  An electret according to Example 1 of the present invention (having the configuration shown on the lower side in FIG. 3) was prepared to have the following configuration. That is, the electret according to the present embodiment is a glass plate (10 mm square), a base electrode (“BE” of the electret shown on the lower side of FIG. 3), and a grid connection electrode (lower side of FIG. 3). As the electret “BGE” shown), after patterning an aluminum layer (thickness of 300 mm) on the above-mentioned substrate at a width of 1 mm and an interval of 100 μm except for both ends, an insulating resin layer (of the electret shown on the lower side of FIG. As “CYTOP”, a Teflon polymer resin (manufactured by Asahi Glass Co., Ltd., trade name CYTOP CTL-M, thickness 3 μm from the base electrode) is further laminated. Moreover, the electret which concerns on a present Example was charged using the charging method to the electret shown in the said embodiment. That is, the base electrode of the electret according to the present embodiment is grounded, a voltage of −8 kV is applied to the needle electrode similar to FIG. 2, and a voltage of −600 V is applied to the grid similar to FIG. And charged by the potential difference.

(Comparative example)
An electret according to the comparative example (having the structure shown on the upper side in FIG. 3) was prepared to have the structure shown below. That is, the electret according to this comparative example has a glass plate (10 mm square) on the substrate, a base electrode (“BE” of the electret shown on the upper side of FIG. 3), and a guard electrode (shown on the lower side of FIG. 3). As an electret “GE”), an aluminum layer is laminated on the substrate to a thickness of 300 mm, and an insulating resin layer (an electret “CYTOP” shown in the upper part of FIG. 3) is a Teflon polymer resin. (Asahi Glass Co., Ltd., trade name CYTOP CTL-M, thickness 3 μm from the base electrode) is further laminated on the base electrode. The base electrode and the guard electrode are formed by patterning at intervals of 1 mm in width and 100 μm except at both ends. Further, the electret according to the comparative example was charged with the configuration shown in FIG. Specifically, the base electrode 53 on the substrate 51 in the electret 50 according to the comparative example is grounded, the guard electrode 52 is insulated, and the needle electrode 61 in FIG. A voltage of −600 V was applied to 60 by a power source 63, and the insulating material layer 54 was charged by the potential difference between the base electrode 53 and the ground electrode.

  The surface potential of the electrets according to Example 1 and the comparative example was measured using a non-contact type surface potential meter (model 279 manufactured by Monroe Electronics). The result is shown in the graph of FIG. In addition, the magnitude | size and position of each width | variety of the electret which concerns on Example 1 and a comparative example in FIG. 3, and the value and position of the graph horizontal axis of FIG. 3 respond | correspond. From the graph of FIG. 3, it can be seen that the potential difference of the electret according to the comparative example is about 60V, while the potential difference of the electret according to Example 1 is greatly improved to about 300V. Therefore, when the electret according to the first embodiment is used as one component of the electrostatic induction conversion element, the power generation efficiency can be significantly improved as compared with the conventional electrostatic induction conversion element.

  Moreover, the electret which concerns on the said Example 1 was used as the electret 10 in the electrostatic induction type conversion element shown in the said embodiment, and the movable part was vibrated with the drive frequency of 20 Hz, and the power generation experiment was done. As a result, power generation of 8 nW could be confirmed.

<Modification>
The present invention can be changed in design without departing from the scope of the claims, and is not limited to the above-described embodiments and examples. For example, the following (A) to (C) are given as modified examples.

(A) As shown in FIG. 5A, the electret 70 has a cavity 76, and the insulating material layer 74 is not formed between the base electrode 73 and the grid connection electrode 72. It differs from the electret 10 of the said embodiment. In addition, each of the site | parts of the codes | symbols 71-73, 75 of Fig.5 (a) is the same as the site | parts of the codes | symbols 11-13,15 of FIG. The electret 70 having such a configuration can achieve the same effects as the electret 10 of the above-described embodiment.

(B) As shown in FIG. 5B, the electret 80 includes an insulating material layer 84 and an insulating material portion 86 made of another material between the base electrode 83 and the grid connection electrode 82. Is different from the electret 10 of the above embodiment. In addition, each part of the codes | symbols 81-83, 85 of FIG.5 (b) is the same as the part of the codes | symbols 11-13,15 of FIG. The electret 80 having such a configuration can achieve the same effects as the electret 10 of the above-described embodiment.

(C) In the electrostatic induction conversion element 100 in the above embodiment, only the movable portion 20 is horizontally vibrated, but the movable portion 20 may be fixed and the electret 10 may be horizontally vibrated, or the movable portion. Both 20 and the electret 10 may be horizontally vibrated.

10, 50, 70, 80 Electret 11, 21, 51 Substrate 12, 72, 82 Grid connection electrode 13, 53, 73, 83 Base electrode 14, 54, 74, 84 Insulating material layer 15, 75, 85 Electrode layer 20 Movable part 22 Electrode 30 Resistance 40, 60 Grid 41, 61 Needle electrode 52 Guard electrode 62, 63 Power source 76 Cavity 86 Insulating material part 100 Static induction type conversion element

Claims (6)

An electrode layer in which base electrodes connectable to the ground and grid connection electrodes connectable to the grid are alternately insulated; and
And an insulating material layer provided on one surface of the electrode layer.   The electret according to claim 1, wherein a spacing portion having a predetermined width is provided between the base electrode and the grid connection electrode.   The electret according to claim 1, wherein an insulating material portion is provided between the base electrode and the grid connection electrode.   The electret according to claim 3, wherein the insulating material layer and the insulating material portion are integrally formed.   An electrostatic induction conversion element comprising the electret according to claim 1. A grid disposing step of disposing a grid on the insulating material layer side of the electret according to any one of claims 1 to 4,
A needle electrode disposing step of disposing a needle electrode on the side opposite to the insulating material layer side of the grid;
A first connection step of connecting a ground and the needle electrode to the base electrode in the electret;
A second connection step of connecting the grid and the grid connection electrode in the electret;
A charging step of applying a predetermined voltage between the needle electrode and the base electrode after the first connection step and the second connection step to charge the insulating material layer in the electret;
An electret charging method comprising: a voltage applying step of applying a predetermined voltage to the grid after the first connecting step and the second connecting step.

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