JP2018157013A - Variable capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable capacitor in which multiple specific capacities can be adjusted, respectively, in a certain range.SOLUTION: A variable capacitor 1 includes first and second variable capacitors 20, 30 connected in parallel and a capacity adjustment mechanism 40. The first variable capacitor has first and second fixed electrodes 21, 2, first and second dielectric layers 22, and a first movable electrode 23 provided slidably between the first and second dielectric layers, and the position in the side direction is adjusted by the capacity adjustment mechanism. The second variable capacitor has a third fixed electrode 31 connected electrically with the first fixed electrode, a fourth fixed electrode 2 connected electrically with the second fixed electrode, third and fourth dielectric layers 32, and a second movable electrode 33 provided slidably between the third and fourth dielectric layers, and the position in the slide direction is adjusted by the capacity adjustment mechanism. Maximum capacitance of the second variable capacitor is smaller than the maximum capacitance of the first variable capacitor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a variable capacitor.

  As a technology in this technical field, there is a capacitor described in Patent Document 1. The capacitor of Patent Document 1 includes both a fixed capacitor and a variable capacitor. In this capacitor, a fixed capacitor provides a large capacitance, while a variable capacitor can finely adjust the capacitance.

Japanese Patent Laid-Open No. 10-144567

  With the configuration of the capacitor described in Patent Literature 1, the capacitance can be finely adjusted with respect to a specific capacitance (the center value of the variable capacitance in Patent Literature 1) defined according to the capacitance of the fixed capacitor. It is. Therefore, the present invention can be applied to a circuit or device that requires the specific capacitance. However, other circuits or devices having different required specific capacitances cannot be accommodated by fine adjustment of the variable capacitors, and it is necessary to prepare other capacitors using different fixed capacitors. Alternatively, even when the same device is driven under different conditions, it is necessary to prepare another capacitor using a different fixed capacitor even when the required specific capacitance is different.

  Therefore, the present invention provides a variable capacitor that can adjust each of a plurality of specific capacitances within a certain range.

  A variable capacitor according to an aspect of the present invention includes a first variable capacitor unit, a second variable capacitor unit electrically connected in parallel to the first variable capacitor unit, the first variable capacitor, and the second variable capacitor. A capacitance adjusting mechanism that adjusts each of the capacitances of the first fixed capacitor, the first variable capacitor section, a first fixed electrode, a second fixed electrode disposed opposite to the first fixed electrode, and the first fixed electrode. A first dielectric layer provided in contact with the first fixed electrode between the electrode and the second fixed electrode; and the second fixed electrode between the first fixed electrode and the second fixed electrode. A second dielectric layer provided in contact with the first dielectric layer and the second dielectric layer, wherein the first dielectric layer and the second dielectric layer are slidable between the first dielectric layer and the second dielectric layer; And the position in the sliding direction by the capacity adjustment mechanism. A first movable electrode to be adjusted, and the second variable capacitor portion is disposed opposite to the third fixed electrode electrically connected to the first fixed electrode and the third fixed electrode. A fourth fixed electrode electrically connected to the second fixed electrode; a third dielectric layer provided in contact with the third fixed electrode between the third fixed electrode and the fourth fixed electrode; A fourth dielectric layer provided in contact with the fourth fixed electrode between the third fixed electrode and the fourth fixed electrode; and between the third dielectric layer and the fourth dielectric layer. A second movable electrode which is slidably provided with respect to the third dielectric layer and the fourth dielectric layer, and whose position in the sliding direction is adjusted by the capacitance adjusting mechanism. The maximum capacitance of the variable capacitor unit is smaller than the maximum capacitance of the first variable capacitor unit. There.

  In the above configuration, the capacitance of the first variable capacitor unit is adjusted by sliding the first movable electrode, and the capacitance of the second variable capacitor unit is adjusted by sliding the second movable electrode. Since the first variable capacitor unit and the second variable capacitor unit are connected in parallel, the capacitance of the variable capacitor is adjusted by changing the capacitance of each of the first variable capacitor unit and the second variable capacitor unit. obtain. Since the maximum capacitance of the second variable capacitor unit is smaller than the maximum capacitance of the first variable capacitor unit, for example, a variable capacitor is set to a specific capacitance in the first variable capacitor unit. Thereafter, the capacitance of the variable capacitor can be finely adjusted by the second variable capacitor unit. Since the specific capacitance set by the first variable capacitor unit can be set by sliding the first movable electrode, each of the plurality of specific capacitances can be adjusted within a certain range in the variable capacitor. .

  The second fixed electrode and the fourth fixed electrode may be a common electrode. Thereby, the number of parts can be reduced.

  The second variable capacitor unit may be stacked on the first variable capacitor unit. As a result, the variable capacitor can be made compact.

  The relative dielectric constant of the first dielectric layer and the relative dielectric constant of the second dielectric layer may be the same. Thereby, it is easy to design the first variable capacitor part and it is easy to prepare a plurality of dielectric layers used for the first variable capacitor part.

The relative dielectric constant of the third dielectric layer and the relative dielectric constant of the fourth dielectric layer may be the same. Thereby, it is easy to design the second variable capacitor part and it is easy to prepare a plurality of dielectric layers used for the second variable capacitor part.

  The relative dielectric constant of the first dielectric layer is the same as that of the second dielectric layer, and the relative dielectric constant of the third dielectric layer is the same as that of the fourth dielectric layer. The relative dielectric constant of the third dielectric layer may be smaller than the relative dielectric constant of the first dielectric layer. Thereby, the design of the first variable capacitor unit and the second variable capacitor unit is easy, and a plurality of dielectric layers used for the first variable capacitor unit and the second variable capacitor unit can be easily prepared. Further, since the relative dielectric constant of the third dielectric layer is smaller than the relative dielectric constant of the first dielectric layer, the maximum capacitance of the second variable capacitor unit is made larger than the maximum capacitance of the first variable capacitor unit. Can be small.

  The capacitance adjusting mechanism includes a first position adjusting unit that adjusts a position of the first movable electrode in the sliding direction, and a second position adjusting unit that adjusts a position of the second movable electrode in the sliding direction. Also good. In this case, the capacity adjustment mechanism may further include a switching unit that switches between the first position adjustment unit and the second position adjustment unit. In the configuration in which the capacity adjustment mechanism includes the switching unit, the switching unit can switch between the first position adjusting unit and the second position adjusting unit, so that the configuration for driving the variable capacitor can be simplified.

  The first variable capacitor portion is disposed opposite to the first fixed electrode on the opposite side of the first fixed electrode and is opposed to the first fixed electrode, and is electrically connected to the second fixed electrode. An electrode, a fifth dielectric layer provided in contact with the first fixed electrode between the first fixed electrode and the fifth fixed electrode, and between the first fixed electrode and the fifth fixed electrode A sixth dielectric layer provided in contact with the fifth fixed electrode, and the fifth dielectric layer and the sixth dielectric layer between the fifth dielectric layer and the sixth dielectric layer. And a third movable electrode that is slidable and whose position in the sliding direction is adjusted by the capacitance adjusting mechanism. In this configuration, it is easy to realize the first variable capacitor unit having the maximum maximum capacitance with respect to the second variable capacitor unit.

  The relative dielectric constants of the first dielectric layer, the second dielectric layer, the fifth dielectric layer, and the sixth dielectric layer are the same, and the relative dielectric constant of the third dielectric layer and the fourth dielectric layer are the same. The relative dielectric constants of the dielectric layers may be the same, and the relative dielectric constant of the third dielectric layer may be smaller than the relative dielectric constant of the first dielectric layer. Thereby, the design of the first variable capacitor unit and the second variable capacitor unit is easy, and a plurality of dielectric layers used for the first variable capacitor unit and the second variable capacitor unit can be easily prepared. Further, since the relative dielectric constant of the third dielectric layer is smaller than the relative dielectric constant of the first dielectric layer, the maximum capacitance of the second variable capacitor unit is made larger than the maximum capacitance of the first variable capacitor unit. Can be small.

  ADVANTAGE OF THE INVENTION According to this invention, the variable capacitor which can adjust each of several specific electrostatic capacitance in a fixed range can be provided.

FIG. 1 is a schematic diagram of an example of a variable capacitor according to the first embodiment. FIG. 2 is a top view of the variable capacitor shown in FIG. FIG. 3 is a drawing when the variable capacitor shown in FIG. 1 is viewed from the direction A in FIG. FIG. 4 is a diagram illustrating changes in capacitance in an example of the variable capacitor according to the first embodiment. FIG. 5 is a schematic diagram of a variable capacitor according to the second embodiment. 6 is a drawing of the variable capacitor shown in FIG. 5 when viewed from the direction A in FIG. FIG. 7 is a diagram illustrating changes in capacitance in an example of a variable capacitor according to the second embodiment. FIG. 8 is a schematic diagram of an example of a variable capacitor according to the third embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same symbols are assigned to the same elements. A duplicate description is omitted. The dimensional ratios in the drawings do not necessarily match those described. In the description, words indicating directions such as “up” and “down” are convenient words based on the state shown in the drawings.

(First embodiment)
The variable capacitor 1 according to the first embodiment will be described with reference to FIGS. FIG. 1 is a schematic diagram of the variable capacitor 1, and schematically shows a cross-sectional configuration along the line II in FIG. FIG. 2 is a top view of the variable capacitor 1 shown in FIG. FIG. 3 is a drawing when the variable capacitor 1 is viewed from the direction A in FIG. For convenience of explanation, three directions orthogonal to each other as shown in FIGS. 1 to 3 may be referred to as an X direction, a Y direction, and a Z direction.

  The variable capacitor 1 includes a case 10, a first variable capacitor unit 20, a second variable capacitor unit 30, and a capacity adjustment mechanism 40.

  The case 10 has a hollow box shape and houses the first variable capacitor unit 20 and the second variable capacitor unit 30. The case 10 has a bottom plate 11, a top plate 12, and four side walls 13, 14, 15, 16. The side wall 13 and the side wall 14 face each other, and the side wall 15 and the side wall 16 face each other. The material of the bottom plate 11, the top plate 12, and the side walls 13, 14, 15, 16 is an insulating material.

  The first variable capacitor unit 20 functions as a variable capacitor for coarse adjustment of capacitance, and the second variable capacitor unit 30 functions as a capacitor for fine adjustment of capacitance. The second variable capacitor unit 30 is laminated on the first variable capacitor unit 20 via a common electrode plate (second fixed electrode, fourth fixed electrode) 2 that is a common electrode with the first variable capacitor unit 20. . In the first embodiment, the stacking direction of the first variable capacitor unit 20 and the second variable capacitor unit 30 is the Z direction.

  The first variable capacitor unit 20 includes a first electrode plate (first fixed electrode) 21, a common electrode plate (second fixed electrode) 2, a pair of dielectric layers 22, and a first movable electrode plate (first movable electrode). Electrode) 23.

  The 1st electrode plate 21 and the common electrode plate 2 are metal plates, and are arrange | positioned facing and parallel. The material of the first electrode plate 21 and the common electrode plate 2 may be the same. The first electrode plate 21 and the common electrode plate 2 function as electrodes for supplying power to the variable capacitor 1. In the X direction, the position of the end face on the side wall 14 side of the first electrode plate 21 is the same as the position of the corresponding end face of the common electrode plate 2. One end of the first electrode plate 21 is drawn from the side wall 13 of the case 10 to the outside of the case 10. One end of the common electrode plate 2 is drawn from the side wall 15 of the case 10 to the outside of the case 10. Of the first electrode plate 21 and the common electrode plate 2, the exposed portion from the case 10 functions as an external connection region of the variable capacitor 1. A connection hole 4 a (see FIG. 2) for connecting a wiring, a bush, or the like may be formed in an exposed portion of the common electrode plate 2 from the case 10.

  One dielectric layer (first dielectric layer) 22 of the pair of dielectric layers 22 is formed on the first main surface 21 a of the first electrode plate 21. The dielectric layer 22 formed on the first major surface 21a is in contact with the first major surface 21a. The other dielectric layer (second dielectric layer) 22 of the pair of dielectric layers 22 is formed on the first main surface 2 a of the common electrode plate 2. The dielectric layer 22 formed on the first major surface 2a is in contact with the first major surface 2a. The contact area between the first main surface 2a and the corresponding dielectric layer 22 is the same as the contact area between the first main surface 21a and the corresponding dielectric layer 22.

  The end surfaces on the side wall 14 side of the pair of dielectric layers 22 are flush with the corresponding end surfaces of the first electrode plate 21 and the common electrode plate 2. The planar view shape (the shape viewed from the Z direction) of the dielectric layer 22 is a rectangle or a square, and the arrangement state (including the size) of the pair of dielectric layers 22 when viewed from the Z direction is the same. .

The dielectric layer 22 is, for example, a ceramic layer. The thickness and relative dielectric constant of the two dielectric layers 22 (ratio of dielectric constant of dielectric layer 22 to vacuum dielectric constant) ε _r 1 are the same. An example of the thickness of the dielectric layer 22 is 0.5 mm to 2 mm. The relative dielectric constant ε _r 1 of the dielectric layer 22 is 1 to 40, for example.

  The first movable electrode plate 23 is a metal plate. The material of the first movable electrode plate 23 may be the same as the material of the first electrode plate 21. The first movable electrode plate 23 is provided between the two dielectric layers 22 so as to be in contact with them and to be slidable with respect to them. In the first embodiment, the sliding direction of the first movable electrode plate 23 is the X direction. The length of the first movable electrode plate 23 in the X direction is longer than the length of the dielectric layer 22, and one end of the first movable electrode plate 23 is drawn from the side wall 14 of the case 10. The first movable electrode plate 23 is slidably provided on the side wall 14.

In the configuration of the first variable capacitor unit 20, the dielectric layer 22, the first movable electrode plate 23, and the dielectric layer are arranged between the first electrode plate 21 and the common electrode plate 2 in order from the first electrode plate 21 side. 22 are stacked. In this configuration, the first electrode plate 21, the dielectric layer 22, and the first movable electrode plate 23 constitute one capacitor (hereinafter referred to as “first subcapacitor”), and the first movable electrode plate 23 and the dielectric The body layer 22 and the common electrode plate 2 constitute one capacitor (hereinafter also referred to as “second sub capacitor”). In the present embodiment, the first sub capacitor and the second sub capacitor have the same configuration and are connected in series. The capacitance of the first variable capacitor section 20 is C, the vacuum dielectric constant is ε0, the relative dielectric constant of air is ε _r 0, and the first surface of the dielectric layer 22 on the first movable electrode plate 23 side is the first. The area of the region in contact with the movable electrode plate 23 is S1, and the area of the dielectric layer 22 on the first movable electrode plate 23 side that is not in contact with the first movable electrode plate 23 is S2. When the thickness of the body layer 22 is d and the thickness of the first movable electrode plate 23 is d0, the capacitance C is expressed by the formula (1).

  In the above formula (1), other than the areas S1 and S2 are constants, and the areas S1 and S2 depend on the length L1 (mm) of the overlapping region between the first movable electrode plate 23 and the dielectric layer 22. Determined. Therefore, the capacitance of the first variable capacitor unit 20 is also determined according to the length L1 of the overlapping region between the first movable electrode plate 23 and the dielectric layer 22. Specifically, when the length L1 is 0, that is, when the first movable electrode plate 23 is not in contact with the dielectric layer 22, the capacitance of the first variable capacitor unit 20 is minimum, In the state where the one movable electrode plate 23 is inserted most into the case 10, the capacitance of the first variable capacitor unit 20 is maximum. Therefore, the capacitance of the first variable capacitor unit 20 can be adjusted by changing the length L1 by sliding the first movable electrode plate 23. An example of the length L1 is 0 mm to 50 mm.

  The second variable capacitor unit 30 has the common electrode plate (fourth fixed electrode) 2 of the first variable capacitor unit 20 as an electrode, and is stacked on the first variable capacitor unit 20. The second variable capacitor unit 30 includes a common electrode plate 2, a second electrode plate (third fixed electrode) 31, a pair of dielectric layers 32, and a second movable electrode plate (second movable electrode) 33. .

  The second electrode plate 31 is a metal plate. The second electrode plate 31 is disposed on the opposite side of the first variable capacitor unit 20 as viewed from the common electrode plate 2, and is disposed opposite to and in parallel with the common electrode plate 2. The material of the second electrode plate 31 may be the same as that of the first electrode plate 21. The second electrode plate 31 also functions as an electrode for supplying power to the variable capacitor 1 together with the common electrode plate 2. In the X direction, the position of the end face on the side wall 14 side of the second electrode plate 31 is the same as the position of the corresponding end face of the common electrode plate 2. One end of the second electrode plate 31 is drawn from the side wall 13 of the case 10 to the outside of the case 10. An exposed portion of the second electrode plate 31 from the case 10 functions as an external connection region of the variable capacitor 1. A connection hole 4b (see FIG. 2) for connecting a wiring, a bush, or the like may be formed in an exposed portion of the second electrode plate 31 from the case 10. The second electrode plate 31 is electrically connected to the first electrode plate 21 outside the case 10. In one embodiment, the second electrode plate 31 is connected to the first electrode plate 21 and the conductive plate 3 as shown in FIG. In this case, the first electrode plate 21, the conductive plate 3, and the second electrode plate 31 can be regarded as a single U-shaped electrode member. The material of the conductive plate 3 may be the same as that of the first electrode plate 21 and the second electrode plate 31. Therefore, the connection hole 4 b may be formed in the first electrode plate 21 or the conductive plate 3.

  One dielectric layer (third dielectric layer) 32 of the pair of dielectric layers 32 is formed on the first major surface 31 a of the second electrode plate 31. The dielectric layer 32 formed on the first major surface 31a is in contact with the first major surface 31a. The other dielectric layer (fourth dielectric layer) 32 of the pair of dielectric layers 32 is formed on the second main surface 2 b of the common electrode plate 2. The dielectric layer 32 formed on the second major surface 2b is in contact with the second major surface 2b. The contact area between the second main surface 2b and the corresponding dielectric layer 32 is the same as the contact area between the first main surface 31a and the corresponding dielectric layer 32.

  The end surfaces on the side wall 14 side of the pair of dielectric layers 32 are flush with the corresponding end surfaces of the second electrode plate 31 and the common electrode plate 2. The planar view shape (shape viewed from the Z direction) of the dielectric layer 32 is the same as that of the dielectric layer 22, and the arrangement state (including size) of the pair of dielectric layers 32 when viewed from the Z direction is also included. The arrangement of the pair of dielectric layers 22 is the same.

The dielectric layer 32 is, for example, a ceramic layer. The relative dielectric constant (ratio of the dielectric constant of the dielectric layer 32 to the vacuum dielectric constant) ε _r 2 of the two dielectric layers 32 is the same. The thickness of the dielectric layer 32 is the same as the thickness of the dielectric layer 22. The relative dielectric constant ε _r 2 of the dielectric layer 32 is smaller than the relative dielectric constant ε _r 1 of the dielectric layer 22. The relative dielectric constant ε _r 2 is 1 to 40, for example. For example, when the relative dielectric constant ε _r 2 is 1 to 40, a value smaller than the relative dielectric constant ε _r 1 may be selected.

  The second movable electrode plate 33 is a metal plate. The material of the second movable electrode plate 33 may be the same as the material of the first electrode plate 21. The second movable electrode plate 33 is provided between the two dielectric layers 32 so as to be in contact with them and to be slidable in the X direction with respect to them. The length of the second movable electrode plate 33 in the X direction is longer than the length of the dielectric layer 32, and one end of the second movable electrode plate 33 is drawn from the side wall 14 of the case 10. The second movable electrode plate 33 is slidably provided on the side wall 14.

  The configuration of the second variable capacitor unit 30 corresponds to a configuration in which the first variable capacitor unit 20 is inverted with respect to the common electrode plate 2 except that the dielectric layer 32 is used instead of the dielectric layer 22. .

In the configuration of the second variable capacitor unit 30, the dielectric layer 32, the second movable electrode plate 33, and the dielectric layer 32 are sequentially disposed between the second electrode plate 31 and the common electrode plate 2 from the common electrode plate 2 side. Are stacked. In this configuration, the common electrode plate 2, the dielectric layer 32, and the second movable electrode plate 33 constitute one capacitor (hereinafter referred to as “third sub-capacitor”), and the second movable electrode plate 33 and the dielectric The layer 32 and the second electrode plate 31 constitute one capacitor (hereinafter also referred to as “fourth sub-capacitor”). In the present embodiment, the third sub capacitor and the fourth sub capacitor have the same configuration and are connected in series. The capacitance of the second variable capacitor unit 30 is defined by an equation that uses the relative dielectric constant ε _r 2 of the dielectric layer 32 instead of the relative dielectric constant ε _r 1 of the dielectric layer 22 in the equation (1). The

  Therefore, the capacitance of the second variable capacitor unit 30 is determined according to the length L2 (mm) of the overlapping region between the second movable electrode plate 33 and the dielectric layer 32. Specifically, when the length L2 is 0, that is, when the second movable electrode plate 33 is not in contact with the dielectric layer 32, the capacitance of the second variable capacitor unit 30 is the minimum, In the state where the movable electrode plate 33 is inserted most into the case 10, the capacitance of the second variable capacitor unit 30 is the maximum. Accordingly, the capacitance of the second variable capacitor unit 30 can be adjusted by changing the length L2 by sliding the second movable electrode plate 33. The variation amount of the length L2 is the same as the variation amount of the length L1.

The configurations of the first variable capacitor unit 20 and the second variable capacitor unit 30 are substantially the same except for the relative dielectric constants of the dielectric layer 22 and the dielectric layer 32, and the relative dielectric constant ε of the dielectric layer 32. _{Since r} 2 is smaller than the relative dielectric constant ε _r 1 of the dielectric layer 22, the maximum capacitance of the second variable capacitor unit 30 is smaller than the maximum capacitance of the first variable capacitor unit 20. For this reason, the variable amount of the capacitance of the second variable capacitor unit 30 is smaller than the variable amount of the capacitance of the first variable capacitor unit 20, and the second variable capacitor unit 30 has the capacitance of the first variable capacitor unit 20. A function of finely adjusting the capacitance with respect to the capacitance can be provided.

  The capacitance adjusting mechanism 40 adjusts the capacitance of each of the first variable capacitor unit 20 and the second variable capacitor unit 30. The capacity adjustment mechanism 40 includes a first position adjustment unit 50 and a second position adjustment unit 60.

  The first position adjustment unit 50 adjusts the capacitance of the first variable capacitor unit 20 by adjusting the position of the first movable electrode plate 23 in the sliding direction (X direction). The first position adjusting unit 50 includes a rod-like screw body 51 that is arranged in parallel with the first movable electrode plate 23 and extends in one direction. The screw body 51 is supported by a support body 52 fixed to the outer surface of the bottom plate 11 of the case 10. The screw body 51 is supported by the support body 52 so as to be movable in the axial direction of the screw body 51 with respect to the support body 52 in accordance with the rotation around the axis. The screw body 51 is provided with a connecting portion 53 that connects the first electrode plate 21 and the screw body 51. The connecting portion 53 is attached to the screw body 51 so as to move together with the screw body 51 in accordance with the movement of the screw body 51. Therefore, when the screw body 51 is moved in the axial direction by rotationally driving the screw body 51, the first movable electrode plate 23 slides and the length L1 is adjusted. The screw body 51 can be driven by connecting a motor to the screw body 51, for example. A knob may be provided at one end of the screw body 51, and the screw body 51 may be rotationally driven by turning the knob manually.

  The second position adjusting unit 60 adjusts the capacitance of the second variable capacitor unit 30 by adjusting the position of the second movable electrode plate 33 in the sliding direction (X direction). The second position adjusting unit 60 includes a rod-shaped screw body 61 that is disposed in parallel with the second movable electrode plate 33 and extends in one direction. The screw body 61 is supported by a support body 62 fixed to the outer surface of the top plate 12 of the case 10. The screw body 61 is supported by the support body 62 so as to be movable in the axial direction of the screw body 61 with respect to the support body 62 as the shaft rotates. The screw body 61 is provided with a connecting portion 63 that connects the second electrode plate 31 and the screw body 61. The connecting portion 63 is attached to the screw body 61 so as to move together with the screw body 61 in accordance with the movement of the screw body 61. Therefore, when the screw body 61 is moved in the axial direction by rotationally driving the screw body 61, the second movable electrode plate 33 slides and the length L2 is adjusted. The rotational driving method of the screw body 61 can be the same as that of the screw body 51.

  In the variable capacitor 1, since the first variable capacitor unit 20 and the second variable capacitor unit 30 are connected in parallel, the variable capacitor 1 has the respective capacitances of the first variable capacitor unit 20 and the second variable capacitor unit 30. Can be determined. Each of the first variable capacitor unit 20 and the second variable capacitor unit 30 can adjust the capacitance by adjusting the slide position of the first movable electrode plate 23 and the second movable electrode plate 33 by the capacitance adjustment mechanism 40. It is configured. That is, the first variable capacitor unit 20 and the second variable capacitor unit 30 function as a slide type variable capacitor.

  The maximum capacitance of the second variable capacitor unit 30 is smaller than the maximum capacitance of the first variable capacitor unit 20. In other words, the maximum capacitance of the first variable capacitor unit 20 is larger than the maximum capacitance of the second variable capacitor unit 30. Therefore, the first variable capacitor unit 20 is used for coarse adjustment of capacitance (for example, adjustment in the range of 0 to several hundred pF), and the second variable capacitor unit 30 is finely adjusted (for example, adjustment of about several pF). Can be used for

  Therefore, when the desired capacitance is realized by the variable capacitor 1, for example, the variable capacitor 1 may be controlled as follows.

  First, the first movable electrode plate 23 of the first variable capacitor unit 20 is slid to realize a specific capacitance (approximate capacitance desired to be realized by the variable capacitor 1). Thereafter, the second movable electrode plate 33 of the second variable capacitor unit 30 is slid to finely adjust the specific capacitance so that the entire variable capacitor 1 has a desired capacitance.

  Since the specific capacitance is determined by the slide amount of the first movable electrode plate 23, the entire variable capacitor 1 can be used for a plurality of specific capacitances corresponding to the slide amount of the first movable electrode plate 23. The electrostatic capacity can be finely adjusted. For this reason, for example, in RF matching, even if the device (for example, plasma processing device) is different, the experimental conditions in a certain device, the manufacturing conditions, etc. are different, and the required capacitance is different, RF matching can be performed with a single variable capacitor 1 with high accuracy. That is, the variable capacitor 1 has versatility.

  Since the first variable capacitor unit 20 can adjust the capacitance roughly and the second variable capacitor unit 30 can finely adjust the capacitance, the amount of variation in the capacitance of the entire variable capacitor 1 is large.

With reference to FIG. 4, the change in capacitance that can be realized by the variable capacitor 1 will be described more specifically. FIG. 4 is a diagram showing the capacitance that can be realized by an example of the variable capacitor 1, and the horizontal axis shows the sum of the length L1 and the length L2. FIG. 4 has a configuration in which the first variable capacitor portion 20 is inverted with respect to the common electrode plate 2 except that the dielectric layer 32 is used instead of the dielectric layer 22, and under the following conditions: The calculation result at the time of designing the variable capacitor 1 is shown.
Dielectric constant ε _r 1:40 of the dielectric layer 22
Dielectric constant ε _r 2: 1 of the dielectric layer 32
Thickness of dielectric layer 22 and dielectric layer 32: 0.5 mm
Maximum length L1 and length L2: 50 mm
Contact area of each of the first electrode plate 21, the common electrode plate 2, and the second electrode plate 31, and the corresponding dielectric layer 22 and dielectric layer 32: 50 (mm) × 50 (mm)

A solid line α in FIG. 4 indicates a change in the capacitance of the variable capacitor 1 when the length L2 is set to 0 and the length L1 is changed in the range of 0 mm to 50 mm. The solid line α corresponds to a change in the capacitance of the first variable capacitor unit 20 because the length L2 is zero. Since the relative dielectric constant ε _r 1 of the dielectric layer 22 is relatively large as 40, the variable amount of the capacitance of the first variable capacitor unit 20 is large. Specifically, the capacitance is changed from 4 pF to 525 pF by changing the length L1 to a maximum of 50 mm.

A broken line β1, a broken line β2, and a broken line β3 in FIG. 4 indicate changes in the capacitance of the variable capacitor 1 when the length L2 is changed while the length L1 is fixed to a constant value. Specifically, each of the broken line β1, the broken line β2, and the broken line β3 indicates a change in the capacitance of the variable capacitor 1 when the length L1 is fixed to 50 mm, 30 mm, and 0 mm. Since the length L1 is a constant value, the broken line β1, the broken line β2, and the broken line β3 correspond to changes in the capacitance of the second variable capacitor unit 30. Since the relative dielectric constant ε _r 2 of the dielectric layer 32 is relatively small as 1 (small relative to the relative dielectric constant ε _r 1), the variable amount of the capacitance of the second variable capacitor unit 30 is small. Specifically, by changing the length L2 to a maximum of 50 mm, the capacitance of the second variable capacitor unit 30 changes from 3.5 pF to 44 pF.

  As understood from FIG. 4, when the length L1 and the length L2 are 50 mm, that is, when the sum of the length L1 and the length L2 is 100 mm, the capacitance of the variable capacitor 1 is the maximum. In the case of FIG. 4, the maximum capacitance is 569 pF. In other words, the variable capacitor 1 used in the calculation of FIG. 4 can adjust the capacitance up to 569 pF.

  As shown in FIG. 1, the variable capacitor 1 is compact in the form in which the variable capacitor 1 has a laminated structure of the first variable capacitor unit 20 and the second variable capacitor unit 30. For example, when viewed from the Z direction, the installation area of the variable capacitor 1 can be reduced.

  The configuration of the second variable capacitor unit 30 corresponds to a configuration in which the first variable capacitor unit 20 is inverted with respect to the common electrode plate 2 except that the dielectric layer 32 is used instead of the dielectric layer 22. In form, the same components can be used except for the dielectric layer. As a result, the number of parts can be reduced and the size can be reduced as described above. As described above, even when the difference between the first variable capacitor unit 20 and the second variable capacitor unit 30 is substantially only the difference in relative dielectric constant between the dielectric layer 22 and the dielectric layer 32, the difference in relative dielectric constant therebetween. Thus, the variable capacitor 1 has the above-described operational effects.

(Second Embodiment)
FIG. 5 is a schematic diagram of a variable capacitor 1A according to the second embodiment, and FIG. 6 is a view when viewed from the A direction of FIG. The variable capacitor 1A is different from the variable capacitor 1 in that the variable capacitor 1A includes a first variable capacitor unit 20A instead of the first variable capacitor unit 20. The variable capacitor 1A will be described focusing on this difference. The second embodiment may be described using the same X direction, Y direction, and Z direction as in the first embodiment.

  In addition to the configuration of the first variable capacitor unit 20, the first variable capacitor unit 20A includes a third electrode plate (fifth fixed electrode) 24, a pair of dielectric layers 25, and a third movable electrode plate (third movable electrode plate). Electrode) 26, and is different from the first variable capacitor unit 20.

  The third electrode plate 24 is a metal plate. The third electrode plate 24 is disposed on the opposite side of the second variable capacitor portion 30 when viewed from the first electrode plate 21, and is disposed opposite to and parallel to the first electrode plate 21. The material of the third electrode plate 24 may be the same as that of the first electrode plate 21. One end of the third electrode plate 24 is drawn from the side wall 15 of the case 10 to the outside of the case 10. The third electrode plate 24 is electrically connected to the common electrode plate 2 outside the case 10. In one embodiment, the third electrode plate 24 is connected by the common electrode plate 2 and the conductive plate 5. In this case, the third electrode plate 24, the conductive plate 5, and the common electrode plate 2 can be regarded as one U-shaped electrode member. The material of the conductive plate 5 may be the same as that of the third electrode plate 24 and the common electrode plate 2.

One dielectric layer (fifth dielectric layer) 25 of the pair of dielectric layers 25 is formed in contact with the second main surface 21 b of the first electrode plate 21. The other dielectric layer (sixth dielectric layer) 25 of the pair of dielectric layers 25 is formed on the first major surface 24 a of the third electrode plate 24. The planar view shape (the shape seen from the Z direction) of the dielectric layer 25 is the same as that of the dielectric layer 22, and the arrangement state (including the size) of the pair of dielectric layers 25 when seen from the Z direction is also a dielectric. Same as for layer 22. The dielectric layer 25 is, for example, a ceramic layer, and the configuration (including material and thickness) of the dielectric layer 22 and the dielectric layer 25 is the same. Therefore, the dielectric constant of the dielectric layer 25 is also the same as the dielectric constant ε _r 1 of the dielectric layer 22.

  The third movable electrode plate 26 is a metal plate. The material of the third movable electrode plate 26 may be the same as the material of the first electrode plate 21. The third movable electrode plate 26 is provided between the pair of dielectric layers 25 so as to be in contact with them and to be slidable with respect to them. One end of the third movable electrode plate 26 is drawn from the side wall 14 of the case 10, and the third movable electrode plate 26 is provided so as to be slidable with respect to the case 10.

  In the variable capacitor 1 </ b> A, the connecting portion 53 included in the first position adjusting unit 50 connects the first movable electrode plate 23, the third movable electrode plate 26, and the screw body 51. For example, the connecting portion 53 passes through the third movable electrode plate 26 and is connected to the first movable electrode plate 23. In this configuration, the first movable electrode plate 23 and the third electrode plate 24 are slid together by the first position adjusting unit 50.

  In the configuration of the first variable capacitor portion 20A, the dielectric layer 25, the third movable electrode plate 26, and the dielectric are arranged between the first electrode plate 21 and the third electrode plate 24 in this order from the first electrode plate 21 side. Layer 25 is laminated. In this configuration, the first electrode plate 21, the dielectric layer 25 and the third movable electrode plate 26 constitute one capacitor (hereinafter referred to as “fifth sub-capacitor”), and the third movable electrode plate 26 and the dielectric The body layer 25 and the third electrode plate 24 constitute one capacitor (hereinafter also referred to as “sixth sub capacitor”). That is, the first variable capacitor unit 20A includes a fifth sub capacitor and a sixth sub capacitor in addition to the first sub capacitor and the second sub capacitor included in the first variable capacitor unit 20 described in the first embodiment.

  In the present embodiment, the configuration of the fifth and sixth sub-capacitors is the same as the configuration of the first and second sub-capacitors. The capacitances of the fifth and sixth sub-capacitors are determined by the length L1 of the overlapping region between the third movable electrode plate 26 and the dielectric layer 25, as in the case of the first and second sub-capacitors. . The capacitance of the first variable capacitor unit 20A can be adjusted by changing the length L1 by sliding the first movable electrode plate 23 and the third movable electrode plate 26.

  The variable capacitor 1A is substantially different from the variable capacitor 1 in that the first variable capacitor unit 20A is provided instead of the first variable capacitor unit 20. The first variable capacitor unit 20A has a configuration other than that the first variable capacitor unit 20 further includes a third electrode plate 24, a pair of dielectric layers 25, and a third movable electrode plate 26. Are the same. Therefore, the variable capacitor 1 </ b> A has at least the same effects as those of the variable capacitor 1.

  In the first variable capacitor section 20A, since the common electrode plate 2 and the third electrode plate 24 are electrically connected, a series structure (corresponding to a series circuit) of the first sub capacitor and the second sub capacitor, The fifth sub-capacitor and the sixth sub-capacitor in series (corresponding to a series circuit) are electrically connected in parallel. For this reason, the maximum capacitance of the first variable capacitor unit 20A is larger than the maximum capacitance of the first variable capacitor unit 20, and the maximum capacitance of the variable capacitor 1A and the variable amount of the capacitance associated therewith are also determined. It is larger than variable capacitor 1.

  With reference to FIG. 7, the change in capacitance that can be realized by the variable capacitor 1A will be described more specifically. FIG. 7 is a diagram illustrating the capacitance that can be realized by an example of the variable capacitor 1A, and the horizontal axis represents the sum of the length L1 and the length L2. 7 shows a variable capacitor 1A designed under the same conditions as those of the variable capacitor 1 for calculation shown in FIG. 4 except that the first variable capacitor unit 20A is used instead of the first variable capacitor unit 20. The calculation results are shown. As described above, the configuration of the dielectric layer 25 is the same as the configuration of the dielectric layer 22.

  A solid line in FIG. 7 indicates a change in capacitance of the variable capacitor 1A, and corresponds to a change curve formed by the solid line α and the broken line β1 in FIG. That is, the solid line in FIG. 7 shows the change in the capacitance of the variable capacitor 1A when the length L1 is changed to 50 mm after the length L1 is changed to 50 mm. For comparison, the broken line in FIG. 7 indicates a change in the capacitance of the variable capacitor 1, and represents a change curve connecting the solid line α and the broken line β1 in FIG.

  As shown in FIG. 7, the variable capacitor 1 </ b> A can achieve a larger capacitance than the variable capacitor 1, and the first variable capacitor unit 20 </ b> A has a larger capacitance than the first variable capacitor unit 20. The variable amount can be realized.

In the second embodiment, the case where the relative dielectric constant ε _r 1 of the dielectric layer 22 (and the dielectric layer 25) is larger than the relative dielectric constant ε _r 2 of the dielectric layer 32 has been described as an example. However, in the configuration of the variable capacitor 1A, the dielectric constant epsilon _{r 1} of the dielectric layer 22 (and the dielectric layer 25) may be the same as the dielectric constant epsilon _{r 2} of the dielectric layer 32. Even in this case, since the first variable capacitor unit 20A includes the dielectric layer 25 and the third movable electrode plate 26, the maximum capacitance of the first variable capacitor unit 20A is set to the maximum electrostatic capacitance of the second variable capacitor unit 30. Can be larger than capacity. A dielectric layer 22 (and the dielectric layer 25) the relative dielectric constant epsilon _{r 1} of the same for the case the difference between the relative dielectric constant epsilon _{r 2} of the dielectric layer 32 is small.

Therefore, in the configuration of the second embodiment, when there is only one type of usable (or ready) dielectric layer, the dielectric constant of the usable (or ready) dielectric layer 22 (and dielectric layer 25) is This configuration is particularly effective when the difference between the dielectric constant ε _r 1 and the relative dielectric constant ε _r 2 of the dielectric layer 32 is small, or when the relative dielectric constant ε _r 1 is small.

(Third embodiment)
FIG. 8 is a schematic diagram of a variable capacitor 1B according to the third embodiment. The variable capacitor 1B is different from the variable capacitor 1 in that it includes a capacity adjustment mechanism 40A instead of the capacity adjustment mechanism 40. The variable capacitor 1B will be described focusing on this difference.

  The capacity adjustment mechanism 40 </ b> A includes a switching unit 70 that switches between them in addition to the first position adjustment unit 50 and the second position adjustment unit 60.

  The switching unit 70 is configured to switch between the first position adjusting unit 50 and the second position adjusting unit 60. In one embodiment, the switching unit 70 includes a rod-shaped screw body 71 and a first rotation direction conversion unit 72 for the first position adjustment unit 50, and a rod-shaped screw body 73 and a second rotation for the second position adjustment unit 60. It has a direction changing part 74, a switching main body part 75, and a rod-like screw body 76.

  The screw body 71 is connected to a portion of the screw body 51 on the outer side (opposite to the support body 52) as viewed from the coupling portion 53 via a first rotation direction conversion portion 72 in a direction intersecting with the screw body 51. . In the present embodiment, the screw body 71 is provided so as to be substantially orthogonal to the screw body 51. The first rotation direction conversion unit 72 converts the rotation around the axis of the screw body 71 into the rotation around the axis of the screw body 51. The first rotation direction conversion unit 72 may be a gear mechanism, for example.

  The screw body 73 is connected to a portion of the screw body 61 on the outer side (opposite to the support body 62) as viewed from the coupling portion 63 via the second rotation direction conversion portion 74 in a direction intersecting with the screw body 61. . In the present embodiment, the screw body 73 is provided so as to be substantially orthogonal to the screw body 61. The second rotation direction conversion unit 74 converts the rotation around the axis of the screw body 73 into the rotation around the axis of the screw body 61. The second rotation direction conversion unit 74 can be, for example, a gear mechanism.

  The switching main body 75 is connected to the screw body 71 and the screw body 73 on the opposite side to the first rotation direction conversion section 72 and the second rotation direction conversion section 74. The switching body 75 is provided with a screw body 76 parallel to the screw body 51 and the screw body 61. The switching main body 75 is configured to be able to switch the connection to the screw body 71 and the connection to the screw body 73. Further, the switching body 75 is configured to be able to transmit the rotation around the axis of the screw body 76 by converting the rotation around the axis of the screw body 71 or the screw body 73 to which the switching body 75 is connected. . The switching main body 75 can be constituted by a gear mechanism, for example.

  The switching between the first position adjusting unit 50 and the second position adjusting unit 60 by the switching unit 70 is not limited to the above form. For example, the screw body 71 and the screw body 73 are arranged apart from each other in the axial direction thereof. In this case, the switching main body 75 can be moved between, for example, the screw body 71 and the screw body 73, and the rotational force of the screw body 76 is applied to the screw body 71 by contacting the screw body 71 and the screw body 76. The switching unit 70 may be configured to transmit the rotational force of the screw body 76 to the screw body 73 by transmitting and contacting the screw body 73.

  The variable capacitor 1B has the same configuration as that of the variable capacitor 1 except that it includes a capacitance adjustment mechanism 40A instead of the capacitance adjustment mechanism 40. The capacitance adjustment mechanism 40A also includes the first variable capacitor unit 20 and the second variable capacitor 1A. The capacitance of the variable capacitor unit 30 can be adjusted. Therefore, the variable capacitor 1B has at least the same effects as the variable capacitor 1.

  The capacity adjustment mechanism 40A included in the variable capacitor 1B includes a switching unit 70, and the switching unit 70 switches between the first position adjustment unit 50 and the second position adjustment unit 60. Accordingly, when adjusting the capacitance of the variable capacitor 1B, one motor may be prepared when the screw body 76 is driven by connecting a motor or the like to the screw body 76 of the switching unit 70. For this reason, it is possible to reduce the weight and the size of the device including the variable capacitor 1B and to reduce the manufacturing cost.

  In the foregoing, various embodiments of the present invention have been described. However, the present invention is not limited to the various embodiments described above, and various modifications can be made without departing from the spirit of the present invention.

  For example, each of the first variable capacitor unit and the second variable capacitor unit is a slide type variable capacitor unit, and the maximum capacitance of the second variable capacitor unit may be smaller than the maximum capacitance of the first variable capacitor unit. . Therefore, for example, the relative dielectric constants of the plurality of dielectric layers included in the first variable capacitor unit may be different, and the relative dielectric constants of the plurality of dielectric layers included in the second variable capacitor unit may be different. . However, by making the relative dielectric constants of the plurality of dielectric layers of the first variable capacitor unit the same, the design of the first variable capacitor unit can be facilitated, and a plurality of dielectrics used for the first variable capacitor unit can be used. Easy to prepare body layer. The same applies to the second variable capacitor unit.

  As long as the first variable capacitor unit and the second variable capacitor unit are electrically connected in parallel, the variable capacitor may not have a stacked structure in which one is stacked on the other. Therefore, for example, the first variable capacitor unit and the second variable capacitor unit may be arranged in parallel in the horizontal direction. Even in this case, the common electrode plate 2 may be used. For example, the first electrode plate 21 and the second electrode plate may be used as a common electrode.

  DESCRIPTION OF SYMBOLS 1,1A, 1B ... Variable capacitor, 2 ... Common electrode plate (2nd fixed electrode, 4th fixed electrode), 20, 20A ... 1st variable capacitor part, 21 ... 1st electrode plate (1st fixed electrode), 22 ... Dielectric layer (first dielectric layer, second dielectric layer), 23 ... first movable electrode plate (first movable electrode), 25 ... dielectric layer (fifth dielectric layer, sixth dielectric layer) , 26 ... third movable electrode plate (third movable electrode), 30 ... second variable capacitor section, 31 ... second electrode plate (third fixed electrode), 32 ... dielectric layer (third dielectric layer, fourth Dielectric layer), 33, second movable electrode plate (second movable electrode), 40, 40A, capacitance adjusting mechanism, 50, first position adjusting unit, 60, second position adjusting unit, 70, switching unit.

Claims (10)

A first variable capacitor section;
A second variable capacitor portion electrically connected in parallel to the first variable capacitor portion;
A capacitance adjusting mechanism that adjusts the capacitance of each of the first variable capacitor and the second variable capacitor;
With
The first variable capacitor unit includes:
A first fixed electrode;
A second fixed electrode disposed opposite to the first fixed electrode;
A first dielectric layer provided in contact with the first fixed electrode between the first fixed electrode and the second fixed electrode;
A second dielectric layer provided in contact with the second fixed electrode between the first fixed electrode and the second fixed electrode;
The first dielectric layer and the second dielectric layer are provided between the first dielectric layer and the second dielectric layer so as to be slidable with respect to the first dielectric layer and the second dielectric layer. A first movable electrode to be adjusted;
Have
The second variable capacitor unit includes:
A third fixed electrode electrically connected to the first fixed electrode;
A fourth fixed electrode disposed opposite to the third fixed electrode and electrically connected to the second fixed electrode;
A third dielectric layer provided in contact with the third fixed electrode between the third fixed electrode and the fourth fixed electrode;
A fourth dielectric layer provided in contact with the fourth fixed electrode between the third fixed electrode and the fourth fixed electrode;
The third dielectric layer and the fourth dielectric layer are provided between the third dielectric layer and the fourth dielectric layer so as to be slidable with respect to the third dielectric layer and the fourth dielectric layer. A second movable electrode to be adjusted;
Have
A maximum capacitance of the second variable capacitor unit is smaller than a maximum capacitance of the first variable capacitor unit;
Variable capacitor. The second fixed electrode and the fourth fixed electrode are common electrodes.
The variable capacitor according to claim 1. The second variable capacitor unit is stacked on the first variable capacitor unit.
The variable capacitor according to claim 1. The relative dielectric constant of the first dielectric layer and the relative dielectric constant of the second dielectric layer are the same.
The variable capacitor as described in any one of Claims 1-3. The relative dielectric constant of the third dielectric layer is the same as that of the fourth dielectric layer.
The variable capacitor as described in any one of Claims 1-3. The relative dielectric constant of the first dielectric layer and the relative dielectric constant of the second dielectric layer are the same,
The relative dielectric constant of the third dielectric layer is the same as that of the fourth dielectric layer,
The relative dielectric constant of the third dielectric layer is smaller than the relative dielectric constant of the first dielectric layer,
The variable capacitor as described in any one of Claims 1-3. The capacity adjustment mechanism is
A first position adjusting unit for adjusting a position of the first movable electrode in the sliding direction;
A second position adjusting unit that adjusts the position of the second movable electrode in the sliding direction;
Having
The variable capacitor according to claim 1. The capacity adjustment mechanism includes a switching unit that switches between the first position adjustment unit and the second position adjustment unit.
The variable capacitor according to claim 7. The first variable capacitor unit includes:
A fifth fixed electrode disposed opposite to the second fixed electrode as viewed from the first fixed electrode and opposed to the first fixed electrode and electrically connected to the second fixed electrode;
A fifth dielectric layer provided in contact with the first fixed electrode between the first fixed electrode and the fifth fixed electrode;
A sixth dielectric layer provided in contact with the fifth fixed electrode between the first fixed electrode and the fifth fixed electrode;
The fifth dielectric layer and the sixth dielectric layer are provided between the fifth dielectric layer and the sixth dielectric layer so as to be slidable with respect to the fifth dielectric layer and the sixth dielectric layer. A third movable electrode to be adjusted;
Having
The variable capacitor according to any one of claims 1 to 5, 7, and 8. The relative dielectric constants of the first dielectric layer, the second dielectric layer, the fifth dielectric layer, and the sixth dielectric layer are the same,
The relative dielectric constant of the third dielectric layer is the same as that of the fourth dielectric layer,
The relative dielectric constant of the third dielectric layer is less than or equal to the relative dielectric constant of the first dielectric layer.
The variable capacitor according to claim 9.

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