JP2003264123A - Variable capacitance element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize the switching operation or the like of an element, and improve resistance to vibration and reliability by using a constitution wherein a movable electrode can be largely driven to both sides by using two driving electrodes. <P>SOLUTION: A coplanar line 3 for signal transmission and a movable body 4 which is displaced via a retaining beam 6 in the vertical direction are installed on a substrate 2. A driving electrode 8 and driving electrodes 12, 14 are installed on both sides of the movable electrode 7 with a movable electrode 7 between. When a voltage is applied across the electrodes 7, 8, the movable electrode 7 is pressed against the line 3 via a dielectric film 10 and cuts off a high frequency signal or the like travelling on the line 3. When a voltage is applied across the electrodes 12, 14, the movable electrode 7, the dielectric film 10, etc., are separated from the line 3, so that the high frequency signal or the like can travel on the line 3. As a result, it can be prevented that the movable electrode 7 is displaced erroneously by vibration, shock, etc., and a variable capacitance switch 1 malfunctions. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable capacitance type switch that performs a switching operation for a high frequency signal or the like by changing an electrostatic capacitance, or a variable capacitance element preferably used as a variable capacitance capacitor or the like.

[0002]

2. Description of the Related Art Generally, as a variable capacitance element, for example, a movable electrode is displaced with respect to a fixed electrode by electrostatic attraction or the like, and an electrostatic capacitance is variably set by changing an interval between these electrodes. Known variable capacitance capacitors and the like are known.

A variable capacitor according to this type of prior art is a support beam which is flexibly deformable on the front surface side of a substrate, almost in the same manner as an electrostatic drive type switch described in, for example, Japanese Patent Laid-Open No. 2000-188050. A movable electrode is provided via the above, and the movable electrode faces the fixed electrode provided on the substrate with a gap. Further, drive electrodes are provided on the substrate and the movable electrode side, respectively, and between the drive electrodes,
An electrostatic attraction is generated by applying a voltage from the outside.

When the voltage is not applied between the drive electrodes, the support beam supports the movable electrode in a free state, so that the electrode interval (electrostatic capacity) between the fixed electrode and the movable electrode becomes a predetermined value. It is set to the size. In addition, when a voltage is applied between the drive electrodes, the support beam or the like is flexibly deformed by the electrostatic attraction and the movable electrode is displaced so as to be close to the fixed electrode, and the electrostatic capacitance between these electrodes increases. Is.

[0005]

By the way, in the above-mentioned prior art, when no voltage is applied to the drive electrodes,
The movable electrode is held at a predetermined position by the rigidity (spring force) of the support beam. However, when using the variable capacitance element, an external force such as vibration or shock may be applied to the substrate.When this external force acts in a direction perpendicular to the substrate, the support beam is flexibly deformed by the external force and the movable electrode is fixed. It may be displaced with respect to the electrode.

Therefore, when the variable capacitor or the like is operated, the electrostatic capacitance of the capacitor may change due to vibration or the like, even though no voltage is applied to the drive electrode, and its vibration resistance and reliability are high. There is a problem that

Further, in the variable capacitance element of the prior art, if the two drive electrodes come into close contact with each other due to electrostatic attraction, they may be stuck even after the voltage is stopped. In such a case, there is also a problem that it is difficult to return the variable capacitance element to a normal operating state only by the restoring force of the support beam or the like.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to prevent the movable electrode from being displaced by an external force and to prevent the drive electrode from being stuck, thereby operating the element. It is an object of the present invention to provide a variable capacitance element capable of stabilizing the state and improving vibration resistance and reliability.

[0009]

In order to solve the above-mentioned problems, the invention of claim 1 is directed to a substrate, a transmission line provided on the substrate for transmitting a signal from the outside, and a signal transmitted through the transmission line. A movable electrode that is displaceably provided on the substrate for switching the transmission state and that is displaced in a direction toward and away from the transmission line, and the movable electrode that is provided on the substrate so as to face the movable electrode and is energized. A first drive electrode for displacing the electrode to a first switching position close to the transmission line; and a movable electrode that is provided on the opposite side of the first drive electrode with the movable electrode sandwiched therebetween and is energized. A configuration including a second drive electrode which is displaced to a second switching position separated from the transmission line is adopted.

With this structure, the first and second drive electrodes can be arranged on both sides of the movable electrode so that a voltage is applied to either one of the first and second drive electrodes. In this case, the movable electrode can be forcibly displaced to the first switching position or the second switching position by electrostatic attraction. As a result, the movable electrode can be largely driven in both directions with respect to the non-energized position. Therefore, even when an external force such as vibration or shock is applied to the substrate, the transmission or interruption state of the high frequency signal to the transmission line can be maintained. It can be switched according to the position.

According to the second aspect of the invention, the transmission line is disposed on the substrate in the vicinity of the first drive electrode, and the first drive electrode and the second drive electrode are provided between the first drive electrode and the second drive electrode. , Second
A movable body displacing between the drive electrodes, the movable body is provided with a movable electrode at a portion facing the transmission line and the first drive electrode, and the movable body is provided with the second drive electrode. A third drive electrode, to which a voltage is applied between the second drive electrode and the second drive electrode, is provided at the facing portion.

Thus, the movable electrode can be displaceably supported by using the movable body. Since the first drive electrode and the movable electrode can be arranged on one side and the second and third drive electrodes can be arranged on the other side with the movable body sandwiched between the electrodes on one side and the electrodes on the other side. By applying a voltage between any one of the electrodes, the movable electrode can be placed close to or away from the transmission line.

According to the third aspect of the present invention, a stopper is provided for holding the movable electrode in the stationary state at the first switching position when the movable electrode is displaced by the first drive electrode.

Thus, when the movable electrode reaches the first switching position by the electrostatic force, for example, a stopper provided on the substrate, the transmission line, the first drive electrode, or the like is brought into contact with the movable electrode, or the movable electrode is moved. The stopper provided on the substrate,
Can be brought into contact with the transmission line, the first drive electrode, etc.,
This allows the movable electrode to be held stationary.

According to the invention of claim 4, the stopper is provided on the movable electrode, and the stopper contacts the transmission line when the movable electrode is displaced to the first switching position.

With this configuration, when the movable electrode reaches the first switching position, the stopper on the movable electrode side can be brought into contact with the transmission line, so that the movable electrode can be held stationary at the first switching position. At the same time, the movable electrode and the transmission line can be insulated by the stopper.

According to the fifth aspect of the invention, the stopper is made of a dielectric material. Accordingly, at the first switching position, the stopper made of the dielectric material is in contact with the transmission line, so that the stopper is separated from the transmission line as compared with the second switching position.
For example, it is possible to greatly increase the capacitance component between the conductors forming the transmission line according to the dielectric constant of the dielectric material,
As a result, it is possible to reliably block the high frequency signal or the like transmitted through the transmission line.

Further, according to the invention of claim 6, the transmission line is formed on the front surface side of the substrate with a thickness larger than that of the first drive electrode. Accordingly, in the first switching position, the stopper on the movable electrode side can surely contact the transmission line without contacting the driving electrode.

Further, according to the invention of claim 7, the stopper is provided on the substrate or the first drive electrode, and the movable electrode is in contact with the stopper when displaced to the first switching position.

With this configuration, when the movable electrode reaches the first switching position, the movable electrode can be brought into contact with the stopper, so that the movable electrode can be held stationary at the first switching position and the movable electrode can be held. The stopper and the transmission line can be insulated from each other.

Further, according to the invention of claim 8, a stopper is provided on the movable body, and when the movable electrode is displaced by the first drive electrode, the stopper keeps the movable electrode stationary at the first switching position. It is configured to hold.

As a result, when the movable electrode reaches the first switching position, the stopper provided on the movable body is set to the substrate, the first position.
The movable electrode can be held stationary at the first switching position, and the movable electrode and the transmission line can be insulated by the stopper.

According to the ninth aspect of the present invention, another stopper is provided for holding the movable electrode stationary at the second switching position when the movable electrode is displaced by the second drive electrode.

Thus, when the movable electrode reaches the second switching position, the movable electrode can be held stationary at the second switching position by bringing another stopper into contact with the surroundings, and the movable electrode vibrates. It is possible to prevent displacement due to impact or the like.

On the other hand, in the invention of claim 10, in order to change the electrostatic capacitance between the substrate, the fixed electrode provided on the substrate, and the fixed electrode, the fixed electrode is movably provided on the substrate. A movable electrode that is displaced toward and away from the first electrode, and a first electrode that is provided on the substrate so as to face the movable electrode and displaces the movable electrode in a direction toward the fixed electrode by applying a voltage. A drive electrode and a second drive electrode which is provided on the opposite side of the first drive electrode with the movable electrode interposed therebetween and which displaces the movable electrode in a direction away from the fixed electrode when a voltage is applied. is doing.

Thus, the first and second drive electrodes can be arranged on both sides of the movable electrode so that the drive electrodes move in both directions with respect to the position when the movable electrode is not energized by electrostatic attraction. It can be forcibly displaced. Therefore, even when an external force such as vibration or shock is applied to the substrate, by controlling the voltages applied to the first and second drive electrodes, respectively, the capacitance between the fixed electrode and the movable electrode can be adjusted in a wide range. Can be changed stably.

Further, according to the invention of claim 11, voltage control means for individually controlling the magnitude of the voltage applied to each of the first and second drive electrodes is provided.
Thus, the voltage control means can control the magnitude relationship of the voltages applied to the first and second drive electrodes, the voltage ratio, etc., so that the movable electrode can be accurately driven in a wide range,
The capacitance between the fixed electrode and the movable electrode can be continuously changed.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, variable capacitance elements according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 to 5 show the first embodiment, and in the present embodiment, a variable capacitance type switch will be described as an example of the variable capacitance element.

In the figure, 1 is a variable capacitance type switch applied to the present embodiment, 2 is a substrate which constitutes the main body of the variable capacitance type switch 1, and the substrate 2 is shown in FIGS. As described above, for example, it is formed in a quadrangular shape by a high resistance silicon material, an insulating glass material, or the like. In addition, on the front surface side of the substrate 2, a concave groove 2A opened facing the movable body 4 described later.
And a lid plate 11 which will be described later and is formed on both sides of the groove 2A.
There are provided left and right joint projections 2B, 2B to which are joined.

Reference numeral 3 denotes a coplanar line as a transmission line provided in the concave groove 2A of the substrate 2, and the coplanar line 3
Are formed of, for example, a plurality of metal films, and are arranged in the vicinity of drive electrodes 8 described later. The coplanar line 3 is a signal conductor 3A for transmitting high-frequency signals and the like.
And the left and right sides of the signal conductor 3A, which are arranged on both the left and right sides of the signal conductor 3A at regular intervals through groove-shaped gaps and are connected to the ground,
It is configured by the right grounding conductors 3B and 3B.

As shown in FIG. 3, the conductors 3A and 3B are formed in a quadrangular sectional shape having a predetermined thickness t0 of, for example, about 0.1 to 50 μm. The counter electrode portion 8 of the drive electrode 8
It is set larger than the thickness t1 of A etc. (t0> t
1).

Reference numeral 4 denotes a movable body which is arranged on the substrate 2 with a gap. The movable body 4 is an elongated rectangular plate-like body together with a supporting beam 6 which will be described later, by etching a silicon plate or the like. It is formed and has a front surface 4A and a back surface 4B. The movable body 4 is supported by a support beam 6 so as to be displaceable in a direction perpendicular to the substrate 2, and is located between the joint protrusions 2B of the substrate 2 and faces the concave groove 2A. Further, on the movable body 4, the front surface 4A, the back surface 4B, etc. of the support beam 6,
Insulating films 5 and 5 made of, for example, a silicon oxide film or a nitride film are provided.

The movable body 4 is driven by using the movable electrode 7 and the drive electrodes 8, 12, and 14 as described later, and the supporting beam 6 is flexibly deformed, so that the movable body 4 is in the non-operating position shown in FIG. From the vertical direction to one side (lower side) or the other side (upper side).

Reference numeral 6 designates, for example, four support beams as a doubly supported beam that supports the movable body 4 on both the left and right sides.
It is formed by bending in a crank shape, and can be flexibly deformed in the vertical direction of the substrate 2. Each support beam 6 has a fixed end 6A fixed to the joint projection 2B of the substrate 2 on the base end side, and fixed to the four corners of the movable body 4 on the tip end side protruding toward the concave groove 2A.

Reference numeral 7 denotes a movable electrode provided on the back surface 4A of the movable body 4 with a coating 5 interposed therebetween. The movable electrode 7 is formed of, for example, a metal film in the shape of an elongated rectangle, and each bonding protrusion 2B of the substrate 2 is formed. It is arranged so as to extend in the left and right directions, and to cross the middle portion in the length direction of the coplanar line 3. Further, the movable electrode 7 faces the conductors 3A and 3B of the coplanar line 3 with an intermediate portion in the left and right directions with a vertical gap, and faces the drive electrodes 8 and 8 on the left and right ends. ing.

As will be described later, the movable electrode 7 is positioned between the drive electrodes 8 and 12 and vertically displaced together with the movable body 4 so that the movable electrode 7 approaches and separates from the coplanar line 3. Signal cut-off position (first switching position) shown in
It is held at any one of the signal transmission positions (second switching positions) shown in FIG. As a result, in the coplanar line 3, the capacitance between the conductors 3A and 3B changes according to the position of the movable electrode 7, so that a high-frequency signal or the like is blocked at the position of the movable electrode 7, and a signal is generated. It is possible to switch between a transmission state in which the movable electrode 7 is sandwiched in between and the transmission state is transmitted to both sides in the length direction.

Reference numeral 8 denotes, for example, two first first electrodes provided on the substrate 2.
As shown in FIGS. 1 to 3, each of the first drive electrodes 8 is formed of, for example, a strip-shaped metal film having a thickness t1, and the concave groove 2A of the substrate 2 and the joining protrusion 2B are formed. They are fixed to each other and are arranged in the vicinity of both the left and right sides of the coplanar line 3.

Each drive electrode 8 has a groove 2A on the substrate 2.
A counter electrode portion 8A that faces the movable electrode 7 with a vertical gap therebetween, and a through hole 9 that extends from the counter electrode portion 8A toward the joint protrusion 2B of the substrate 2 and is formed in the substrate 2 It is configured by a connecting portion 8B connected to an external power source (not shown) or the like.

The drive electrode 8 generates an electrostatic attractive force between the movable electrode 7 and the drive electrode 8 by applying a DC voltage or the like between the left and right drive electrodes 8, and this The movable body 4 is displaced in a direction in which the movable body 4 approaches the coplanar line 3 by electrostatic attraction. This causes the movable electrode 7 to move to the position shown in FIG.
As shown in FIG. 4, the dielectric film 10 described later is pressed against the coplanar line 3 and held at a signal cutoff position close to the conductors 3A and 3B.

Reference numeral 10 denotes a dielectric film provided as a first stopper on the movable electrode 7. The dielectric film 10 is made of a dielectric material such as a silicon oxide film or a nitride film, and has a thickness of, for example, 0.01. It is formed with a thickness of about 50 μm.

Then, as shown in FIG. 4, the dielectric film 10 contacts the conductors 3A and 3B of the coplanar line 3 when the movable electrode 7 is displaced to the signal blocking position, and the movable electrode 7 is connected to the coplanar line 3 and the conductor 3A. It is insulated from the drive electrode 8 and, in cooperation with the electrostatic attraction between the electrodes 7 and 8, holds the movable electrode 7 in a stationary state at the signal interruption position.

In this case, the thickness t0 of the coplanar line 3
Is formed to be thicker than the thickness t1 of the drive electrode 8, the dielectric film 10 does not contact the drive electrode 8 when the movable electrode 7 is in the signal blocking position, and the dielectric film 10 and the movable electrode 7 are not in contact with the drive electrode 8. It will be in a state of being intervened without a gap between it and 7. Thereby, the electrostatic capacitance between the conductors 3A and 3B of the coplanar line 3 can be largely changed between when the movable electrode 7 is at the signal cutoff position and when it is at the signal transmission position, and the variable capacitance switch 1 Can be reliably switched between a transmission state and a cutoff state.

Reference numeral 11 denotes a cover plate provided over the concave groove 2A of the substrate 2. As shown in FIGS. 1 and 2, the cover plate 11 is made of, for example, a high-resistance silicon material or an insulating glass material. A rectangular groove 11A is formed on the back surface side of the concave groove 11A that is open to face the concave groove 2A of the substrate 2, and the bonding protrusions 2B of the substrate 2 are formed on both sides of the concave groove 11A. The left and right joint protrusions 11B and 11B are provided. Further, the fixed portion 6A of each support beam 6, the connection portion 8B of each drive electrode 8 and the like are connected to the joint projections 2B and 11 of the substrate 2 and the cover plate 11.
It is sandwiched between B.

Reference numeral 12 denotes a second drive electrode provided on the cover plate 11. The second drive electrode 12 is made of, for example, a metal film, as shown in FIG. 2, and has a movable body 4 (movable electrode 7). It is arranged on the opposite side of the drive electrode 8 in the direction perpendicular to the drive electrode 8. Further, the drive electrode 12 has a counter electrode portion 12A facing a drive electrode 14 described later with a vertical gap in the groove 11A of the cover plate 11, and a through hole 13 formed in the cover plate 11, for example.
A connecting portion 1 that extends from the counter electrode portion 12A to the front surface side of the lid plate 11 via the above and is connected to an external power source (not shown) or the like.
2B and.

The drive electrode 12 generates an electrostatic attractive force between the electrodes 12 and 14 when a direct current voltage or the like is applied between the drive electrode 12 and the drive electrode 14, and is moved by the electrostatic attractive force. The body 4 is displaced in the direction away from the coplanar line 3. As a result, as shown in FIG. 5, the movable electrode 7 is held at the signal transmission position separated from the coplanar line 3 by contacting the drive electrode 12 with the insulating film 16 described later.

Reference numeral 14 denotes a third drive electrode provided on the surface 4A of the movable body 4 with the coating film 5 interposed therebetween.
Is made of, for example, a metal film, as shown in FIGS.
The drive electrodes 12 are opposed to each other with a vertical gap.
In addition, the drive electrode 14 includes, for example, two wiring portions 14A drawn to the position of the fixed portion 6A through the front surface side of the support beam 6.
Each wiring portion 14A is connected to an external power source (not shown) or the like through a through hole 15 or the like formed in the cover plate 11.

Reference numeral 16 denotes an insulating film provided on the drive electrode 14 as a second stopper. The insulating film 16 is made of an insulating material such as a silicon oxide film or a nitride film. Then, as shown in FIG. 5, the insulating film 16 contacts the drive electrode 12 when the movable electrode 7 is displaced to the signal transmission position, insulates the drive electrodes 12 and 14 from each other, and at the same time, these electrodes 12, 14 are formed. Movable electrode 7 in cooperation with electrostatic attraction between
Is held stationary at the signal transmission position.

Variable capacitance switch 1 according to the present embodiment
Has a configuration as described above, and its operation will be described below.

First, when a voltage is applied between the two drive electrodes 8, an electrostatic attractive force is generated between the drive electrodes 8 and the movable electrode 7, as shown in FIG. As a result, the movable body 4 is displaced downward to a position where the dielectric film 10 comes into contact with the coplanar line 3 due to the bending and deformation of the support beam 6. The movable electrode 7 and the drive electrodes 8 are electrostatically coupled to each other via the dielectric film 10 to form the coplanar line 3.
And is held stationary at the signal blocking position by the dielectric film 10.

As a result, the movable electrode 7 and the dielectric film 10 are arranged between the signal conductor 3A and the grounding conductor 3B of the coplanar line 3, and these conductors 3 are arranged.
The electrostatic capacitance between A and 3B greatly increases in accordance with the dielectric constant of the dielectric film 10 and the like as compared with the case where the movable electrode 7 is separated. Therefore, the conductors 3A and 3B are in a state of being short-circuited at the position of the movable electrode 7 with respect to the AC signal having the frequency (resonance frequency) f determined by the following formula (1).

[0052]

[Equation 1]

As a result, when a high frequency signal of frequency f is input to one side of the coplanar line 3 in the length direction, the high frequency signal is totally reflected at the position of the movable electrode 7, so that the signal is transmitted to the other side of the coplanar line 3. The transmission to the side can be blocked, and the variable capacitance type switch 1 can be turned off (OFF).

On the other hand, when a voltage is applied between the drive electrodes 12 and 14, as shown in FIG.
Due to the generation of electrostatic attraction between the movable bodies 4, the movable body 4 is displaced upward to a position where the insulating film 16 contacts the drive electrode 12. The movable electrode 7 is held stationary by the insulating film 16 at the signal transmission position.

As a result, the coplanar line 3 is substantially unaffected by the movable electrode 7, the dielectric film 10 and the like, and the capacitance between the conductors 3A and 3B is reduced, so that a high frequency signal is transmitted over the entire length of the coplanar line 3. As a result, the variable capacitance type switch 1 can be switched to the transmission (ON) state.

Thus, according to the present embodiment, the drive electrode 8 and the drive electrode 12 are provided on both sides of the movable electrode 7 with the movable electrode 7 interposed therebetween, and electrostatic attraction is generated by these drive electrodes 8 and 12 to generate the movable electrode 7. Is configured to be displaced between the signal cut-off position and the signal transmission position. Therefore, the electrodes 7, 8 and the electrodes 12, 14 are
By applying a voltage between any one of the electrodes, the movable electrode 7 can be forcibly displaced to the signal blocking position or the signal transmitting position by electrostatic attraction.

As a result, the movable electrode 7 can be largely driven to both sides in the vertical direction with respect to the non-energized position. Therefore, even when an external force such as vibration or shock is applied to the substrate 2, the movable electrode 7 can be moved to the position. The variable capacitance switch 1 can stably switch the transmission and interruption states of high-frequency signals, etc.
It is possible to surely prevent the erroneous operation due to external force and the unstable switch operation.

Further, for example, when the coplanar line 3 and the dielectric film 10 are fixed and the movable electrode 7 is fixed at the signal blocking position, an electrostatic attractive force is generated between the drive electrodes 12 and 14. The dielectric film 10 can be reliably separated from the coplanar line 3, and the movable electrode 7 can be quickly returned to the normal state. Further, even when the movable electrode 7 is fixed at the signal transmission position, it is possible to easily release the fixed state of the movable electrode 7 by generating an electrostatic attractive force between the electrodes 7 and 8.

Therefore, the switching operation of the variable capacitance type switch 1 can be stabilized, and its vibration resistance and reliability can be improved. Further, the transmission state of the high frequency signal or the like can be largely changed between the signal transmission position and the cutoff position, and the performance as the switch element can be improved.

In this case, the thickness t0 of the coplanar line 3 is made larger than the thickness t1 of the drive electrode 8, and the movable electrode 7
The dielectric film 10 interposed between the dielectric film 10 and the coplanar line 3.
Since the movable electrode 7 is displaced to the signal cutoff position, the dielectric film 10 can be brought into contact with the coplanar line 3 by the dielectric film 10 between the coplanar line 3 and the movable electrode 7. It can be surely insulated. In addition, the movable electrode 7 is connected to the electrostatic attraction between the electrodes 7 and 8 and the dielectric film 1
With 0, the signal can be stably held at the signal cutoff position, and it is possible to prevent the movable electrode 7 from being displaced due to vibration or the like, or the operation at the time of signal cutoff becoming unstable.

Moreover, when the movable electrode 7 is held at the signal blocking position, the dielectric film 10 on the movable electrode 7 side can be brought into contact with the coplanar line 3, so that the movable electrode 7 is at the signal transmission position. Compared with the case, the conductor 3A,
The capacitance between 3B can be greatly increased by the dielectric film 10, and the high frequency signal and the like transmitted through the coplanar line 3 can be blocked more reliably.

Further, the insulating film 16 is provided on the drive electrode 14 so as to be located between the drive electrode 12 and the drive electrode 12. Therefore, when the movable electrode 7 is displaced to the signal transmission position, the insulation film 16 is formed on the drive electrode 12. Can be brought into contact with each other, and drive electrodes 12, 1
The insulating film 16 can ensure reliable insulation between the four.
Then, the movable electrode 7 can be stably held at the signal transmission position by the electrostatic attraction between the electrodes 12 and 14 and the insulating film 16.

The movable body 4 is displaceably supported by each support beam 6, a movable electrode 7 is provided on the back surface 4B side of the movable body 4, and a drive electrode 14 is provided on the front surface 4A side of the movable body 4. Therefore, the movable body 4 is moved to the left by each supporting beam 6 which is a double-supported beam.
The movable electrodes 7 can be supported in a balanced manner on both right sides, and the movable electrode 7 can be stably displaced in a horizontal state with respect to the substrate 2. Also,
The movable electrode 7 made of a metal film or the like and the drive electrode 14 can be arranged in a necessary portion of the movable body 4, and the variable capacitance type switch 1
The degree of freedom in design can be increased.

Next, FIGS. 6 to 8 show a second embodiment of the present invention.
Of the present invention, and the feature of this embodiment is that a variable capacitor is configured. In this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 21 is a variable capacitance capacitor according to the present embodiment. The variable capacitance capacitor 21 is similar to the variable capacitance type switch according to the first embodiment, and the substrate 2, the movable body 4, the support beam 6, and the movable beam 6 are movable. Electrode 7, drive electrodes 8, 12, 1
4, the dielectric film 10, the cover plate 11, the insulating film 16 and the like. However, in the concave groove 2A of the substrate 2, a fixed electrode 22 described later is provided instead of the coplanar line 3 of the first embodiment.

Reference numeral 22 denotes, for example, two fixed electrodes which constitute the variable capacitor 21, and each fixed electrode 22 is shown in FIG.
As shown in FIG. 7, for example, it is formed of a strip-shaped elongated metal film or the like, and is arranged on both front and rear sides of the substrate 2 with a space. The fixed electrode 22 extends from the counter electrode portion 22A facing the movable electrode 7 with a gap in the vertical direction to the outside of the movable body 4 and is connected to the input side of a signal processing circuit 23 described later. And a connecting portion 22B.

Reference numeral 23 denotes a signal processing circuit as a voltage control means connected to the variable capacitor 21, and the signal processing circuit 23 has its output side connected to the drive electrodes 8 as shown in FIG.
12 and 14, and the input side thereof is connected to each fixed electrode 22. Then, the signal processing circuit 23 individually controls the voltage Va applied between the drive electrodes 8 and the voltage Vb applied between the drive electrodes 12 and 14, and these voltages V
The magnitude relationship between a and Vb and the voltage ratio are variably set.

As a result, the movable electrode 7 moves in the vertical direction from the non-actuated position (intermediate position) shown in FIG. 7 in accordance with the magnitude relationship between the voltages Va and Vb output from the signal processing circuit 23 and the voltage ratio. Are continuously displaced toward both sides of the fixed electrode 22 and are moved toward and away from the fixed electrode 22.

Then, each fixed electrode 2 through the movable electrode 7
The capacitance between the two electrodes is set to the maximum value when the movable electrode 7 is displaced in the direction in which the movable electrode 7 approaches the fixed electrode 22 and the dielectric film 10 comes into contact with the fixed electrode 22, and the movable electrode 7 is fixed to the fixed electrode 22.
The insulating film 16 is displaced in a direction away from the drive electrode 12
Is set to the minimum value when it comes into contact with. Therefore, the signal processing circuit 23 can continuously change the capacitance between the fixed electrodes 22 over a wide range between the maximum value and the minimum value.

Thus, in this embodiment having such a structure, it is possible to obtain substantially the same operational effects as those of the first embodiment. In particular, in the present embodiment, the capacitance of the variable capacitor 21 can be variably set in a wide range by the signal processing circuit 23, and the performance as a capacitor can be improved.

In each of the above embodiments, the movable electrode 7 is provided with the dielectric film 10 serving as a stopper.
The present invention is not limited to this, and may be configured, for example, as a first modification shown in FIG. 9. In this case, the concave groove 2 of the substrate 2 '
A stopper 31 that contacts the movable electrode 7 instead of the dielectric film 10 is provided in A ′. Further, for example, as shown by an imaginary line in FIG. 9, the movable body 4 may be provided with a stopper 31 ′ or the drive electrode 8 may be provided with a stopper 31 ″. The number is not limited to 16, and the movable body 4, the cover plate 11, the drive electrode 12, and the like may be provided.

Further, in each of the embodiments, the movable electrode 7 made of a metal film or the like is provided on the movable body 4, but the present invention is not limited to this. For example, a second modification shown in FIG. You may comprise. In this case, the movable body 4'is formed as a movable electrode of, for example, a metal material or a low resistance silicon material, and is connected to the outside through a conductive support beam 6 ', a fixed portion 6A', etc., and driven. The electrodes 8 and 12 are configured to be displaced to both sides in the vertical direction. Further, the movable electrode 7, the drive electrode 14 and the like used in each embodiment are omitted.

Further, in the first embodiment, the portion where the conductors 3A and 3B of the coplanar line 3 and the dielectric film 10 are in contact with each other is formed as a flat surface substantially horizontal to the substrate 2. However, the conductors 3A ′ and 3 of the coplanar line 3 ′ are not limited to the third modification shown in FIG.
By providing the convex portion 32 and the concave portion 33 that abut against each other at the contact portion between B ′ and the dielectric film 10 ′, the contact area between them may be increased to further increase the capacitance.

Further, in the first embodiment, the movable electrode 7
Although the dielectric film 10 is provided in a portion of the movable electrode 7 facing the coplanar line 3 and the drive electrode 8, the present invention is not limited to this, and the dielectric film 10 is provided only in a portion of the movable electrode 7 facing the coplanar line 3. A film may be provided and the dielectric film in the portion facing the drive electrode 8 may be eliminated. In this case, the thickness t0 of the coplanar line 3 and the thickness t1 of the drive electrode 8 may be formed to have substantially the same size.

Furthermore, in the first embodiment, the coplanar line 3 is described as an example, but the present invention is not limited to this, and for example, a slot line in which a groove (slot) is provided between two conductors or the like. It may be configured to be applied to various transmission lines including.

[0076]

As described above in detail, according to the invention of claim 1, first and second drive electrodes are provided on both sides of the movable electrode, and the first and second drive electrodes are movable. A first switching position where the electrode is close to the transmission line and a second position where the electrode is separated from the transmission line
Since it is configured to be displaced between the switching position of
By applying a voltage to one of the second drive electrodes, the movable electrode can be forcibly displaced to the first switching position or the second switching position by electrostatic attraction. As a result, the movable electrode can be largely driven on both sides in the vertical direction with respect to the non-energized position, and the transmission state of the high frequency signal or the like can be largely changed between the first and second switching positions. Even when an external force such as vibration or shock is applied to the substrate, the signal switching operation can be stably performed according to the position of the movable electrode. Further, for example, when the movable electrode is fixed to one of the first and second drive electrodes, an electrostatic attractive force is generated on the other electrode to bring the movable electrode into a normal state. And can be easily restored. Therefore, it is possible to surely prevent the variable capacitance element from malfunctioning due to external force, sticking of electrodes, etc.
The vibration resistance and reliability can be improved.

According to a second aspect of the invention, the movable body is provided with a movable electrode at a portion facing the transmission line and the first drive electrode, and a third movable electrode is provided at a portion facing the second drive electrode. Since the drive electrode is provided in the movable body, the movable electrode made of a metal film or the like and the third drive electrode can be disposed in a necessary portion of the movable body, and these are stably provided by a support beam or the like provided in the movable body. In addition to being able to support the variable capacitance element, the degree of freedom in designing the variable capacitance element can be increased.

Further, according to the invention of claim 3, since the stopper for holding the movable electrode in the stationary state at the first switching position is provided, the movable electrode reaches the first switching position by the electrostatic force. In some cases, the movable electrode can be held in a stable stationary state at the first switching position by the stopper, the movable electrode can be prevented from being erroneously displaced due to vibration, impact, etc., and the operating state of the variable capacitance element can be stabilized. it can.

Further, according to the invention of claim 4, since the stopper is provided on the movable electrode and comes into contact with the transmission line when the movable electrode is displaced to the first switching position, the stopper is provided at the first switching position. Can bring the stopper on the movable electrode side into contact with the transmission line, hold the movable electrode stationary in the first switching position, and insulate the movable electrode from the transmission line by the stopper. .

Further, according to the invention of claim 5, since the stopper is made of a dielectric material, at the first switching position, for example, the capacitance component between the respective conductors constituting the transmission line is changed to the dielectric material. It can be greatly increased by the stopper consisting of, and thereby the high frequency signal and the like transmitted through the transmission line can be surely blocked.

Further, according to the invention of claim 6, since the transmission line is formed on the front surface side of the substrate so as to have a thickness larger than that of the first drive electrode, the movable electrode side is formed at the first switching position. The stopper can be reliably brought into contact with the transmission line without coming into contact with the drive electrode.

Further, according to the invention of claim 7, since the stopper is provided on the substrate or the first drive electrode, the movable electrode is brought into contact with the stopper,
The movable electrode can be held stationary in the first switching position, and the movable electrode and the transmission line can be insulated.

Further, according to the invention of claim 8, since the movable body is provided with the stopper which comes into contact with the substrate side, the movable body can be moved by bringing the stopper into contact with the substrate, the first drive electrode and the like. The electrode can be held stationary in the first switching position and the movable electrode and the transmission line can be insulated.

Further, according to the invention of claim 9, since another stopper for holding the movable electrode in the stationary state at the second switching position is provided, when the movable electrode reaches the second switching position. By bringing the other stopper into contact with the surroundings, the movable electrode can be held stationary at the second switching position, and the movable electrode can be prevented from being displaced by vibration, impact, or the like.

On the other hand, according to the tenth aspect of the present invention, the first and second drive electrodes are provided on both sides of the movable electrode with the movable electrode interposed between the movable electrode and the fixed electrode. Since the configuration is such that the movable electrodes are displaced toward and away from each other by applying a voltage to one of the first and second drive electrodes, the movable electrodes are moved to both sides in the vertical direction by electrostatic attraction. Can be forcibly displaced, and the displacement amount can be set large. Therefore, even when external vibration or shock is applied, by controlling the voltages applied to the first and second drive electrodes, respectively, the capacitance between the fixed electrode and the movable electrode can be stabilized in a wide range. Can be changed.

Further, according to the invention of claim 11, since the voltage control means for individually controlling the magnitude of the voltage applied to each of the first and second drive electrodes is provided,
The voltage control means can stably control, for example, the magnitude relationship of the voltages applied to the first and second drive electrodes, the voltage ratio, and the like, whereby the electrostatic capacitance between the fixed electrode and the movable electrode can be controlled in a wide range. Can be changed continuously.

[Brief description of drawings]

FIG. 1 is a plan view showing a variable capacitance switch according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the variable capacitance switch as seen from the direction of arrows II-II in FIG.

3 is an enlarged cross-sectional view of a main part in FIG. 2 showing a coplanar line, a drive electrode, and the like.

FIG. 4 is a cross-sectional view showing a state in which movable electrodes and the like are displaced to a signal blocking position.

FIG. 5 is a cross-sectional view showing a state in which movable electrodes and the like are displaced to a signal transmission position.

FIG. 6 is a plan view showing a variable capacitor according to a second embodiment of the present invention.

7 is a cross-sectional view of the variable capacitor seen from the direction of arrows VII-VII in FIG.

FIG. 8 is a circuit diagram showing a state in which a variable capacitor and a signal processing circuit are connected.

FIG. 9 is an enlarged cross-sectional view of a main part of a variable capacitance switch according to a first modification of the present invention when viewed from the same position as in FIG.

FIG. 10 is a sectional view showing a variable capacitance switch according to a second modification of the present invention.

FIG. 11 is an enlarged cross-sectional view of a main part of a variable capacitance switch according to a third modified example of the present invention as viewed from the same position as in FIG.

[Explanation of symbols]

1 Variable capacitance type switch 2,2 'substrate 2A, 11A concave groove 2B, 11B joint protrusion 3 Coplanar line (transmission line) 3A, 3B, 3A ', 3B' conductors 4,4 'movable body 4A surface 4B back side 5 film 6,6 'Support beam 6A, 6A 'fixing part 7 movable electrode 8 First drive electrode 8A, 12A, 22A Counter electrode part 8B, 12B, 22B connection 9, 13, 15 through holes 10,10 'Dielectric film (stopper) 11 lid plate 12 Second drive electrode 14 Third drive electrode 14A wiring section 16 Insulating film (other stopper) 21 Variable capacitors 22 Fixed electrode 23 Signal processing circuit (voltage control means) 31, 31 ', 31 "stopper

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masato Kobayashi             2-10-10 Tenjin, Nagaokakyo, Kyoto Stock             Murata Manufacturing Co., Ltd.

Claims (11)

[Claims] 1. A substrate, a transmission line provided on the substrate for transmitting a signal from the outside, and displaceably provided on the substrate for switching a transmission state of a signal transmitted through the transmission line with respect to the transmission line. A movable electrode which is displaced in a direction in which the movable electrode is moved closer to and away from the movable electrode; A drive electrode and a second drive electrode which is provided on the opposite side of the first drive electrode with the movable electrode interposed therebetween and which is energized to displace the movable electrode to a second switching position spaced from the transmission line. A variable capacitance element configured by. 2. The transmission line is disposed on the substrate in the vicinity of the first drive electrode, and the first and second drive electrodes are provided between the first drive electrode and the second drive electrode. A movable body that is displaced between the movable body and the movable electrode, the movable electrode is provided at a portion facing the transmission line and the first drive electrode, and the movable body faces the second drive electrode. The variable capacitance element according to claim 1, wherein a third drive electrode to which a voltage is applied is provided between the portion and the second drive electrode. 3. The variable according to claim 1, further comprising a stopper for holding the movable electrode stationary at the first switching position when the movable electrode is displaced by the first drive electrode. Capacitive element. 4. The variable capacitance element according to claim 3, wherein the stopper is provided on the movable electrode, and the stopper comes into contact with the transmission line when the movable electrode is displaced to the first switching position. . 5. The variable capacitance element according to claim 4, wherein the stopper is formed by using a dielectric material. 6. The variable capacitance element according to claim 5, wherein the transmission line is formed on the front surface side of the substrate with a thickness larger than that of the first drive electrode. 7. The variable capacitor according to claim 3, wherein the stopper is provided on the substrate or the first drive electrode, and the movable electrode comes into contact with the stopper when the movable electrode is displaced to the first switching position. element. 8. The movable body is provided with a stopper, and the stopper holds the movable electrode in a stationary state at the first switching position when the movable electrode is displaced by the first drive electrode. The variable capacitance element according to claim 2. 9. A stopper provided for holding the movable electrode stationary at the second switching position when the movable electrode is displaced by the second drive electrode.
The variable capacitance element according to 4, 5, 6, 7 or 8. 10. A substrate, a fixed electrode provided on the substrate, and displaceably provided on the substrate for changing electrostatic capacitance between the fixed electrode and the fixed electrode, and is placed close to and away from the fixed electrode. A movable electrode that displaces in a direction, a first drive electrode that is provided on the substrate so as to face the movable electrode, and displaces the movable electrode in a direction in which the movable electrode approaches the fixed electrode, and the movable electrode. And a second drive electrode which is provided on the opposite side of the first drive electrode with the voltage sandwiched therebetween and which displaces the movable electrode in a direction in which the movable electrode is separated from the fixed electrode by applying a voltage. 11. The variable capacitance element according to claim 10, further comprising voltage control means for individually controlling the magnitude of the voltage applied to each of the first and second drive electrodes.