JP2009238546A - Micro electric machine switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a micro electric machine switch capable of contacting a fixed contact and a movable contact with an equal contact pressure. <P>SOLUTION: The micro electric machine switch is provided with a movable contact support table 1 having a table part 10 of which on one face side in thickness direction a movable contact 2 is installed and three pieces of arm parts 11 which have flexibility and support the table part 10 on a base substrate 5, a pair of fixed contacts 3 which are arranged opposed to the movable contact 2 on one face side of the table part 10, and three actuators 4 which are provided respectively on three arm parts 11 and deform the arm parts 11 in a state that the movable contact 2 of the table part 10 may contact both of the pair of fixed contacts 3. The three arm parts 11 have the same shape respectively, and are arranged in a form going along the diameter direction of a circle C centered on the movable contact 2 on a surface orthogonal to the thickness direction of the table part 10, and the angle θ between the adjoining arm parts 11 in the surface is equally 120 degrees. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a microelectromechanical switch such as a MEMS switch or a NEMS switch.

  Conventionally, various micro electromechanical switches such as MEMS switches and NEMS switches have been proposed. As this type of microelectromechanical switch, there is an electrostatic microrelay for high-frequency signal transmission as shown in Patent Document 1.

  As shown in FIG. 9, as shown in FIG. 9, a fixed substrate 100 in which a fixed electrode 120 and two signal lines 130 are provided on an upper surface of a glass substrate 110, and the fixed substrate 100 are integrated. And the movable substrate 200. The movable substrate 200 elastically supports the two movable electrodes 230 via the first elastic support portion 220 by the two anchors 210 and elastically supports the movable contact portion 250 via the second elastic support portion 240 at the center thereof. It is a configuration. A movable contact 270 is formed on the surface of the movable contact portion 250 facing the fixed substrate 100 via an insulating film 260.

The above-described electrostatic micro relay is a so-called normally open type relay, and normally the movable contact 270 and the two signal lines 130 are not in contact with each other, and the two signal lines 130 are disconnected. . In driving this relay, a predetermined drive voltage is applied between the movable electrode 230 of the movable substrate 200 and the fixed electrode 120 formed on the fixed substrate 100. As a result, an electrostatic attractive force (Coulomb attractive force) is generated between the movable electrode 230 and the fixed electrode 120, and each of the two movable electrodes 230 moves toward the fixed substrate 100, and is movable as the movable electrode 230 moves. The contact 270 also moves to the fixed substrate 100 side. As a result, the movable contact 270 contacts both of the two signal lines 130 and the two signal lines 130 are conducted.
Japanese Patent No. 3852224

  As described above, in the electrostatic micro relay disclosed in Patent Document 1, the movable electrode 270 provided on both sides of the movable contact 270 moves to the fixed substrate 100 side, so that the movable contact 270 moves to the fixed substrate 100 side. Therefore, when the electrostatic attractive force generated in one movable electrode 230 is stronger than the electrostatic attractive force generated in the other movable electrode 230, the movable contact 270 may move toward the fixed substrate 100 in a tilted state. If the movable contact 270 is tilted during movement, the contact pressure between the movable contact 270 and the signal line 130 is not equalized, and deviation occurs (for example, the contact pressure at the contact portion of the movable contact 270 with the signal line 130). May be relatively high and relatively low. Such uneven contact pressure may cause deterioration of high-frequency characteristics and sticking.

  The present invention has been made in view of the above-described points, and an object thereof is to provide a micro electromechanical switch capable of bringing a fixed contact and a movable contact into contact with each other with an equal contact pressure.

  In order to solve the above-mentioned problems, in the invention of claim 1, a base part provided with a movable contact on one surface side in the thickness direction, one end is connected to the base part, and the other end is fixed to the base substrate. A movable contact support base provided with a plurality of flexible arm portions that support the portion movably in the direction along the thickness direction, and a pair of opposed contact with the movable contact on the one surface side of the base portion A fixed contact, and a plurality of actuators that individually deform each arm so that the movable contact of the base provided on each arm is in contact with both of the pair of fixed contacts, and each arm has the same shape And arranged in a shape along the radial direction of a circle centered on the movable contact in a plane orthogonal to the thickness direction of the base, and the number of arm portions is an integral multiple of 3, and adjacent in the plane The angle between the arm parts to be It is characterized in.

  According to the invention of claim 1, the arm portions that support the base portion have the same shape, and are arranged in a shape along the radial direction of the circle centering on the movable contact in a plane orthogonal to the thickness direction of the base portion. In addition, since the angles between adjacent arm portions in the plane are all equal and the number of arm portions is an integral multiple of 3, two moments acting on the base portion due to the deformation of the arm portions are not two. Since it is possible to cancel with the above arm parts, compared to the case where the number of arm parts is two or four, the base part becomes difficult to tilt when the base part is moved (the movable contact is difficult to tilt), The fixed contact and the movable contact can be contacted with equal contact pressure. As a result, it is possible to suppress the deterioration of the high frequency characteristics and the occurrence of sticking.

  According to a second aspect of the present invention, in the first aspect of the invention, a dummy contact that is brought into contact with the movable contact is provided together with each of the fixed contacts, and each of the fixed contact and the dummy contact faces the movable contact on the same plane. Each of the fixed contact and the dummy contact is located on the same circumference centering on the movable contact in the plane, and between the contact parts on the circumference. These distances are equal to each other.

  According to the second aspect of the present invention, since the movable contact contacts not only the pair of fixed contacts but also the dummy contacts, the contact state between the movable contact and the fixed contacts is more stable than when contacting only the pair of fixed contacts. Therefore, the contact pressure between the fixed contact and the movable contact can be made more uniform. As a result, it is possible to further suppress the deterioration of the high frequency characteristics and the occurrence of sticking.

  According to a third aspect of the present invention, in the second aspect of the present invention, the fixed contacts and the dummy contacts are arranged so as not to face any of the arm portions in the thickness direction of the base portion. And

  According to the invention of claim 3, capacitive coupling between the fixed contact or dummy contact and the actuator provided in the arm portion can be prevented.

  In the invention of claim 4, in the invention of any one of claims 1 to 3, the peripheral part of the part where the movable contact is formed in the base part is formed in a corrugated cross section. It is characterized by.

  According to the fourth aspect of the present invention, since the base part is easily deformed, the power consumed by the actuator when the base part is moved can be reduced.

  The invention of claim 5 is characterized in that, in the invention of claim 4, a void for reducing the rigidity of the platform is formed in the peripheral portion.

  According to the invention of claim 5, since the rigidity of the base part can be reduced and the base part can be more easily deformed, the electric power consumed by the actuator when the base part is moved can be further reduced. it can.

  According to a sixth aspect of the present invention, in any one of the first to third aspects of the present invention, one end of each arm portion is integrally connected to the base portion via a spring portion having elasticity. And

  According to the sixth aspect of the invention, it is possible to reduce the power consumed by the actuator when moving the platform.

  In the invention of claim 7, in the invention of any one of claims 1 to 6, the actuator includes a lower electrode formed on at least one of the fixed contact side and the opposite side in the arm part, A piezoelectric material portion formed on the opposite side of the lower electrode to the arm portion side; and an upper electrode formed on the piezoelectric material portion on the opposite side of the lower electrode side. The arm portion is deformed by deforming the piezoelectric material portion by applying a predetermined driving voltage therebetween.

  According to the seventh aspect of the present invention, since the amount of displacement of the base portion can be increased while suppressing the power consumption of the actuator as compared with the case of using electrostatic attraction, the distance between the movable contact and the fixed contact can be increased. It can be expanded to reduce signal leakage, and isolation characteristics can be improved.

  According to an eighth aspect of the present invention, in the invention according to any one of the first to sixth aspects, the actuator includes a lower electrode formed on at least one of the fixed contact side and the opposite side of the arm portion, and the lower electrode. A piezoelectric material portion formed on the opposite side of the lower electrode to the arm portion side and an upper electrode formed on the opposite side of the piezoelectric material portion to the lower electrode side are provided, and a predetermined gap is provided between the lower electrode and the upper electrode. A main driving means for deforming the arm portion by applying a driving voltage to the movable portion, a movable electrode formed on the fixed contact side of the movable contact support base, and a thickness direction of the base portion The fixed electrode is arranged so as to overlap the movable electrode, and a predetermined driving voltage is applied between the movable electrode and the fixed electrode so that an electrostatic attractive force is generated between the movable electrode and the fixed electrode. The base portion by for antibody characterized in that it has a secondary drive means for moving the said pair of fixed contact side.

  According to the invention of claim 8, the actuator is composed of a main drive means for deforming the arm part using deformation of the piezoelectric material part and a sub-drive means for deforming the arm part using electrostatic attraction. Therefore, by moving the platform by the main drive means, the displacement of the platform can be increased while keeping the power consumption of the actuator low compared to when using electrostatic attraction. The distance between the contact and the fixed contact can be widened to reduce signal leakage and improve the isolation characteristics, while the auxiliary drive means can set the contact pressure between the movable contact and the fixed contact to a desired value. it can.

  The present invention has an effect that the fixed contact and the movable contact can be brought into contact with each other with an equal contact pressure.

(Embodiment 1)
The microelectromechanical switch according to the present embodiment is, for example, a MEMS switch used for transmission of a high-frequency signal. As shown in FIGS. 1A to 1C, one surface side of the base substrate 5 (FIG. 1 ( The movable contact support 1 formed on the upper surface side in b) is provided. The movable contact support base 1 includes a base part 10 provided with a movable contact 2 on one surface side in the thickness direction (upper surface side in FIG. 1B), one end fixed to the base part 10, and the other end A plurality of flexible arms (three in this embodiment) that are fixed to the base substrate 5 and are movably supported in a direction along the thickness direction (vertical direction in FIG. 1B). The unit 11 is provided.

  Furthermore, the micro electromechanical switch of the present embodiment is provided on each of the pair of fixed contacts 3 disposed opposite to the movable contact 2 on the one surface side of the base 10 and the three arms 11 and is movable on the base 10. Three actuators 4 are provided for deforming the arm portion 11 so that the contact 2 contacts both of the pair of fixed contacts 3.

  The base substrate 5 is formed of, for example, an insulating material (for example, ceramic or glass), and the movable contact support 1 is formed on the one surface side. The one surface of the base substrate 5 is a flat surface. In FIG. 1A, the base substrate 5 is not shown.

  The movable contact support 1 is made of an elastic and insulating material (for example, non-doped polysilicon). Therefore, each of the base part 10 and the arm part 11 has flexibility.

  The base part 10 is formed in a perfect circle (perfect circle) disk shape. The movable contact 2 has a circular shape and is formed at the center of the base 10. Further, the outer peripheral shape of the movable contact 2 and the outer peripheral shape of the platform 10 are concentric circles. The arm portion 11 is formed by integrating a standing piece 11a erected on the one surface of the base substrate 5, a tip portion (upper end portion in FIG. 1B) of the standing piece 11a, and an edge portion of the base portion 10. It is formed in an L-shaped cross section integrally provided with a belt-like (long rectangular plate-like) arm piece 11b connected to the arm. In the micro electromechanical switch of this embodiment, the length direction of the arm piece 11b and the length direction of the standing piece 11a are orthogonal to each other.

  By the way, the length direction (longitudinal direction) of the arm piece 11b of the arm portion 11 is in a plane orthogonal to the thickness direction of the base portion 10 (hereinafter, abbreviated as “in the orthogonal plane”), that is, in the plan view, the movable contact 2. It is made to correspond with the direction along the radial direction (direction equal to the radial direction of the base part 10) of the circle C centering on (center of the movable contact 2). Further, as shown in FIG. 1A, the angles θ between the center lines of the adjacent arm portions 11 in the orthogonal plane (the angles between the center lines of the adjacent arm pieces 11b) θ are all equal. . Therefore, the angles between the adjacent arm portions 11 in the orthogonal plane are all equal. In addition, since the micro electromechanical switch of this embodiment has the three arm parts 11, angle (theta) is 120 degree | times.

  As described above, in the micro electromechanical switch of the present embodiment, the three arm portions 11 have the same shape, are arranged along the radial direction of the circle C, and are adjacent in the orthogonal plane. The angle θ between the arm portions 11 to be operated is 120 degrees and is equal. Therefore, the shape of the movable contact support 1 is three-fold symmetric in the orthogonal plane.

  In the movable contact support 1 described above, for example, a sacrificial layer (not shown) is formed on the one surface side of the base substrate 5, and then an insulating layer (not shown) serving as a basis of the movable contact support 1 is provided. It can be formed by covering the sacrificial layer, then patterning the insulating material layer into a desired shape using photolithography technology, etching technology, etc., and finally removing the sacrificial layer. . In addition, the formation method of the movable contact support stand 1 mentioned above is an example to the last, and you may form with a well-known micromachining technique etc. Further, the material of the movable contact support 1 is not limited to the above-described non-doped polysilicon, and a metal material having elasticity may be used. In this case, it is necessary to form an insulating layer on the surface.

  The fixed contact 3 is formed in a band shape (long rectangular plate shape), and one is used as an input signal line and the other is used as an output signal line. The pair of fixed contacts 3 are formed on a cover 6 that houses the movable contact support 1 between the surface of the base substrate 5. In addition, illustration of the cover 6 is abbreviate | omitted in FIG. 1 (a), (c).

  The cover 6 is formed of, for example, an insulating substrate (for example, a glass substrate). A recess 6a is formed on the surface of the cover 6 facing the base substrate 5 (the lower surface in FIG. 1B). Each fixed contact 3 is formed on the inner bottom surface 6 b of the recess 6 a of the cover 6. Each fixed contact 3 is connected to a conductor pattern 7 formed on the surface opposite to the inner bottom surface 6b (upper surface in FIG. 1B) of the cover 6 by a through-hole wiring 6c formed in the cover 6. Such a cover 6 is joined to the one surface side of the base substrate 5 so as to house the movable contact support 1 in the recess 6a. The cover 6 and the base substrate 5 can be bonded by eutectic bonding or frit bonding. In addition, anodic bonding, surface activated bonding, or the like can be used by selecting materials for the cover 6 and the base substrate 5.

  Incidentally, in addition to the pair of fixed contacts 3, one dummy contact 8 is also formed on the cover 6. The dummy contact 8 is brought into contact with the movable contact 2 together with the pair of fixed contacts 3, and is formed on the inner bottom surface 6b of the recess 6a in the same manner as the fixed contact 3. The dummy contact 8 is formed in the same strip shape (long rectangular plate shape) as the fixed contact 3. Therefore, the opposed surfaces of the fixed contacts 3 and the dummy contacts 8 to the movable contact 2 are located on the same plane.

  Here, the length direction (longitudinal direction) of each of the pair of fixed contacts 3 and the dummy contacts 8 is matched with the direction along the radial direction of the circle C as shown in FIG. Further, as shown in FIG. 1A, the angle between the adjacent fixed contacts 3 in the orthogonal plane and the angle between the fixed contact 3 and the dummy contact 8 are all equal (that is, 120). Degrees). Further, in the orthogonal plane, the distances from the center of the movable contact 2 in the pair of fixed contact 3 and dummy contact 8 are all equal. In addition, the pair of fixed contacts 3 and the dummy contacts 8 are arranged so that the angle with the arm portion 11 in the orthogonal plane is 60 degrees, thereby three arm portions in the thickness direction of the base portion 10. 11 is not opposed to any of the above. As described above, in the micro electromechanical switch of this embodiment, the pair of fixed contact 3 and dummy contact 8 have the contact portion with the movable contact 2 on the same circumference centering on the movable contact 2 in the orthogonal plane. The distance between the contact portions located on the circumference is equal to the distance dividing the circumference into three equal parts.

  As shown in FIGS. 1 and 2, the actuator 4 is formed on the fixed contact side in the arm portion 11, that is, on one surface side in the thickness direction of the arm piece 11b of the arm portion 11 (upper surface side in FIG. 1B). The lower electrode 40a, the piezoelectric material part 41 formed on the side opposite to the arm part 11 side in the lower electrode 40a (the upper side in FIG. 1B), and the side opposite to the lower electrode 40a side in the piezoelectric material part 41 And an upper electrode 42a formed on the upper side in FIG.

  The lower electrode 40a is formed at the end of the arm piece 11b opposite to the base 10 side. Here, in the base substrate 5, a first insulating thin film 43 is formed in the vicinity of a portion where each standing piece 11 a is formed, and the first insulating thin film 43 is opposite to the base substrate 5 side. A conductor pattern 40b for the lower electrode 40a and a conductor pattern 42b for the upper electrode 42a are formed (on the upper surface side in FIG. 1B). The lower electrode 40a and the upper electrode 42a are respectively connected to the conductor patterns 40b and 42b by connection portions 40c and 42c formed on the standing piece 11a of the arm portion 11. The conductor pattern 42b and the connecting portion 42c are formed on the second insulating thin film 44 in order to ensure insulation from the lower electrode 40a and the like.

  By the way, the piezoelectric material portion 41 is a rectangular thin film formed of a piezoelectric material (piezoelectric material) such as piezoelectric ceramics (PZT as an example). This piezoelectric material part 41 is polarized so that the direction along the thickness direction is the polarization axis direction. The actuator 4 utilizes the piezoelectric effect, and when applying a driving voltage between the lower electrode 40a and the upper electrode 42a, the driving voltage is applied so that the spontaneous polarization of the piezoelectric material portion 41 increases. As a result, the piezoelectric material portion 41 extends in the thickness direction and contracts in a direction orthogonal to the thickness direction. Therefore, when the actuator 4 is driven (that is, a predetermined drive voltage is applied between the lower electrode 40a and the upper electrode 42a), the end of the arm piece 11b on the base 10 side moves to the fixed contact 3 side. As described above, the arm piece 11b is deformed (curved). In the present embodiment, a so-called unimorph type piezoelectric actuator is illustrated as the actuator 4, but the present invention is not limited to this. For example, a bimorph type piezoelectric actuator can be adopted as the actuator 4, and in this case, the deformation amount of the arm piece 11 b can be made larger than that of the unimorph type. In the above example, PZT, which is a kind of lead-based piezoelectric material, is exemplified as the material of the piezoelectric material portion 41. However, as long as it is a lead-based piezoelectric material, not only PZT but, for example, an impurity is added to PZT. In addition, the material of the piezoelectric material portion 41 is not limited to the lead-based piezoelectric material, for example, KNN (potassium sodium niobate), KN (potassium sodium), Lead-free piezoelectric materials (lead-free piezoelectric ceramics) such as NN (niobium sodium) and KNN added with impurities (for example, Li, Nb, Ta, Sb, Cu, etc.) can be used. Here, the above-described lead-based piezoelectric material, KNN, KN, NN, and the like have a larger piezoelectric constant than AlN, ZnO, and the like. Therefore, if the above-described lead-based piezoelectric material, KNN, KN, NN, or the like is used as the material of the piezoelectric material portion 41, even if the drive voltage value is the same, compared to the case where AlN, ZnO, or the like is used. The deformation amount of the arm piece 11b can be increased. If a lead-free piezoelectric material such as KNN is used as the material of the piezoelectric material portion 41, the environmental load can be reduced.

  A method for manufacturing such an actuator 4 will be briefly described. First, after the first insulating thin film 43 and the movable contact support 1 are formed on the base substrate 5, a sputtering method, a chemical vapor deposition (CVD) method, or the like is used on the one surface side of the base substrate 5. Then, a metal layer serving as a base of the lower electrode 40a is formed. Thereafter, the lower electrode 40a, the conductor pattern 40b, and the connection portion 40c are formed by patterning the metal layer into a desired planar shape using a photolithography technique and an etching technique. In addition, as a metal layer used as the foundation of the lower electrode 40a, a Pt layer, Au layer, etc. are employable, for example. As the metal layer, a multi-layer structure such as a Pt / Ti layer can be employed.

  After the lower electrode 40a is formed, a piezoelectric layer serving as the basis of the piezoelectric material portion 41 is formed on the one surface side of the base substrate 5 by using a sputtering method, a CVD method, or the like. Thereafter, the piezoelectric thin film 41 is formed by patterning the piezoelectric thin film into a desired planar shape using a photolithographic technique and an etching technique.

After the piezoelectric material portion 41 is formed, a second insulating thin film 44 is formed on the one surface side of the base substrate 5, and thereafter, the second insulating thin film 44 is utilized by using a photolithography technique and an etching technique. The unnecessary portion is removed to obtain the second insulating thin film 44 having the structure shown in FIGS. The first insulating thin film 43 can be formed by a method similar to that for the second insulating thin film 44. Further, as the material of the first insulating thin film 43 and the second insulating thin film 44, SiO ₂ or the like can be adopted.

  After the formation of the second insulating thin film 44, a metal layer serving as the basis of the upper electrode 42a (for example, a metal layer serving as the basis of the lower electrode 40a) is formed on the one surface side of the base substrate 5 by using a sputtering method, a CVD method, or the like. The same material is used). Thereafter, the metal layer is patterned into a desired planar shape using a photolithographic technique and an etching technique to form the upper electrode 42a, the conductor pattern 42b, and the connection portion 42c. 2 is obtained.

  In the microelectromechanical switch of the present embodiment described above, the movable contact 2 and the fixed contacts 3 are spaced apart from each other and the pair of fixed contacts 3 are disconnected when the actuator 4 is not driven. When the actuator 4 is driven, the arm piece 11b of the arm portion 11 is deformed as described above, so that the base portion 10 is moved by the arm portion 11 so as to approach the fixed contact 3 side. As a result, the movable contact 2 of the base portion 10 comes into contact with the pair of fixed contacts 3 and the dummy contact 8, and the pair of fixed contacts 3 are electrically connected. Thereafter, when the driving of the actuator 4 is stopped, the arm portion 11 returns to the shape before deformation, and the base portion 10 moves to the base substrate 5 side. As a result, the movable contact 2 is separated from the pair of fixed contacts 3. Thus, the pair of fixed contacts 3 is blocked.

  And according to the micro electromechanical switch of this embodiment, the three arm parts 11 which support the base part 10 are the same shape, are arrange | positioned along the radial direction of the said circle C, and are in the said orthogonal plane Since the angles between the adjacent arm portions 11 are equal and the number of the arm portions 11 is three, the moment acting on the pedestal portion 10 due to the deformation of the arm portions 11 is not two but two arms. Since it can be offset by the part 11, the base part 10 is less inclined when the base part 10 is moved than when the number of the arm parts 11 is two or four (in other words, the movable contact 2 is inclined). The fixed contact 3 and the movable contact 2 can be brought into contact with a uniform contact pressure. As a result, it is possible to suppress the deterioration of the high frequency characteristics and the occurrence of sticking.

  Further, since the movable contact 2 contacts not only the pair of fixed contacts 3 but also the dummy contacts 8, it is possible to prevent the contact between the movable contacts 2 and the fixed contacts 3 as compared with the case of contacting only the pair of fixed contacts 3. Since the contact state between the movable contact 2 and the fixed contact 3 is stabilized, the contact pressure between the fixed contact 2 and the movable contact 3 can be made more uniform. As a result, it is possible to further suppress the deterioration of the high frequency characteristics and the occurrence of sticking. In addition, since the pair of fixed contacts 3 and the dummy contacts 8 are arranged so as not to face any of the three arm portions 11 in the thickness direction of the base portion 10, the fixed contacts 3 or the dummy contacts 8 and the arm portions are arranged. 11 can be prevented from being capacitively coupled to the actuator 4.

  By the way, in the thing used for transmission of a high frequency signal like the electrostatic micro relay shown in the said patent document 1, the leakage of the signal between signal lines at the time of a contact open | release becomes a problem. As a method of improving the isolation characteristics by suppressing such signal leakage, the distance between the movable contact part (corresponding to the movable contact) and the signal line (corresponding to the fixed contact) when the contact is opened (movable) It has been proposed to widen the distance between the contact and the fixed contact. However, when the gap between the movable contact and the fixed contact is widened to such an extent that good isolation characteristics can be obtained, as shown in Patent Document 1, the contact is opened and closed using electrostatic attraction. During driving, a relatively large voltage (for example, 30 V) must be applied between the movable electrode and the fixed electrode. For this reason, in the above-mentioned Patent Document 1, if the isolation characteristic is improved, the power consumption is increased, and if the reduction of the power consumption is attempted, the isolation characteristic cannot be sufficiently improved. That is, it has been difficult to achieve both improvement in isolation characteristics and reduction in power consumption.

  Therefore, in the micro electromechanical switch according to the present embodiment, the actuator 4 uses a piezoelectric effect rather than an electrostatic attractive force. Here, the actuator 4 using the piezoelectric effect can increase the amount of displacement of the pedestal 10 while keeping power consumption low as compared with the actuator 4 using electrostatic attraction. For example, even if a voltage of about 30 V is required for a device using electrostatic attraction, the contact can be closed with a voltage of about 5 to 10 V using a piezoelectric effect.

  Therefore, according to the microelectromechanical switch of the present embodiment, the movable contact 2 is fixed to the movable contact 2 while keeping power consumption low as compared with the conventional example in which the contact opening / closing operation is performed using electrostatic attraction. Signal leakage can be reduced by widening the gap with the contact 3, and isolation characteristics can be improved.

  Note that the microelectromechanical switch of this embodiment is merely an embodiment of the present invention, and is not intended to limit the technical scope of the present invention to that of this embodiment, but to the spirit of the present invention. Changes can be made without departing from the scope. For example, the number of arm portions 11 is not limited to three, and may be an integer multiple of 3 (3n; where n is an integer of 2 or more). In this case, the shape of the movable contact support 1 is 3n rotationally symmetric in the orthogonal plane. Even in this case, the same effect as that of the present embodiment can be obtained. Moreover, the outer periphery shape of the base part 10 is not limited to a disk-shaped thing, A polygonal shape may be sufficient. In the present embodiment, the lower electrode 40a of the actuator 4 is formed on the fixed contact 3 side in the arm portion 11, but on the opposite side to the fixed contact 3 side in the arm portion 11 (in the thickness direction of the arm piece 11b). It may be formed on the other surface side. Further, the lower electrode 40a may be formed on both the fixed contact 3 side and the opposite side of the arm portion 11. By the way, in this embodiment, the surface side (upper surface side in FIG.1 (b)) opposite to the base substrate 5 side in the base part 10 is made into the one surface side of the thickness direction of the base part 10 which forms the movable contact 2. FIG. However, the surface side (the lower surface side in FIG. 1B) of the pedestal 10 that faces the base substrate 5 may be one surface side in the thickness direction of the pedestal 10 (that is, the movable contact 2 is formed as shown in FIG. 1B). It may be formed on the lower surface of the pedestal 10 in FIG. In this case, the pair of fixed contacts 3 are arranged to face the movable contact 2 on the side of the base 10 facing the base substrate 5, and the actuator 4 moves the arm 11 so that the base 10 approaches the base substrate 5. Configured to deform. Even if it is a case where it deform | transforms in this way, the effect similar to the above can be acquired. The points described above are the same in Embodiments 2 to 4 described later.

(Embodiment 2)
As shown in FIGS. 3A to 3C, the micro electromechanical switch of the present embodiment is different from the first embodiment in the shape of the pedestal 10, and the other configurations are the same as those in the first embodiment. Similar components are denoted by the same reference numerals and description thereof is omitted. In addition, illustration of the base substrate 5 and the cover 6 is abbreviate | omitted in Fig.3 (a), and illustration of the cover 6 is abbreviate | omitted in FIG.3 (c).

  The base part 10 in the present embodiment is formed in a perfect circular (circular) disk shape, a disk-shaped support part 10a in which the movable contact 2 is formed, and an annular frame in which the support part 10a is arranged inside. And a deformable portion 10c that connects the support portion 10a and the frame-like portion 10b. The outer peripheral shape of the support portion 10a and the outer peripheral shape of the frame-like portion 10b are concentric circles. In the deformed portion 10c, the cross-sectional shape in a plane passing through the thickness direction of the pedestal 10 and the radial direction of the pedestal 10 is formed in a corrugated shape (wave shape) as shown in FIGS. It has a bellows shape. That is, as for the base part 10 in this embodiment, the cross-sectional shape is formed in the corrugated part in the peripheral part (deformation part 10c) of the site | part (support part 10a) in which the movable contact 2 was formed in the base part 10. FIG. Therefore, the base part 10 in this embodiment has the deformation | transformation part 10c, and the base part 10 is easy to expand | extend to radial direction.

  Thus, in the micro electromechanical switch of this embodiment, since the base part 10 is easy to deform | transform, the electric power consumed by the actuator 4 when moving the base part 10 can be reduced. That is, in the micro electromechanical switch as in the present embodiment, when the base part 10 is moved to the fixed contact 3 side by the arm part 11, the base part 10 is pulled outward in the radial direction by the arm part 11. In order to contact the fixed contact 3, it is necessary to deform not only the arm part 11 but also the base part 10 by the actuator 4, but the base part 10 is easily deformed as described above. The driving force that needs to be generated by the actuator 4 can be reduced.

  By the way, as shown in FIG. 4, the deformation | transformation part 10c may form the cavity 10d for the rigidity reduction of the base part 10. As shown in FIG. In FIG. 4, illustration of the fixed contact 3, the dummy contact 8, the base substrate 5, and the cover 6 is omitted.

  In the example shown in FIG. 4, the voids 10 d are formed of through holes that penetrate the peripheral part 10 in the thickness direction of the base part 10, and six are formed in the deformed part 10 c. The void 10d is formed in a shape along the radial direction of the platform 10 (a shape in which the longitudinal direction is along the radial direction of the platform 10), and the angle between adjacent voids 10d in the orthogonal plane is any Is equal to 60 degrees.

  If such a void 10d is formed, the rigidity of the pedestal 10 can be reduced and the pedestal 10 can be more easily deformed than that shown in FIG. In this case, the power consumed by the actuator 4 can be further reduced.

  The above-described void 10d is preferably formed so as to be positioned between the arm part 11 and the support part 10a in the radial direction of the base part 10, and in this way, the base part 10 can be more easily deformed. can do. In addition, the void 10d is preferably formed so as not to face either the fixed contact 3 or the dummy contact 8 in the thickness direction of the pedestal 10, and in this way, the capacity with the fixed contact 3 or the dummy contact 8 is increased. Bonding can be prevented.

  Note that the void 10d is not necessarily a through-hole penetrating the deformable portion 10c, and may be a groove or a notch (notch). In short, it is only necessary that the rigidity of the base portion 10 can be reduced.

(Embodiment 3)
As shown in FIGS. 5A to 5C, the micro electromechanical switch of the present embodiment is different from the first embodiment in the shape of the movable contact support base 1, and the other configurations are the same as those in the first embodiment. Therefore, the same components are denoted by the same reference numerals and description thereof is omitted. In addition, illustration of the base substrate 5 and the cover 6 is abbreviate | omitted in Fig.5 (a), and illustration of the cover 6 is abbreviate | omitted in FIG.5 (c).

  The movable contact support base 1 in the present embodiment has a base portion 10 and an arm portion 11 as in the first embodiment, but one end of each arm portion 11 has an elastic spring portion 12 that is elastic. It is different from the first embodiment in that it is integrally connected to the edge. The base 10 is the same as that of the first embodiment except that it has a disk shape with a shorter diameter than that of the first embodiment, and the arm 11 is the same as that of the first embodiment. Is omitted.

  The spring portion 12 is formed to expand and contract mainly in the radial direction of the base portion 10. In the case of the present embodiment, the spring part 12 includes a straight part 12a extending in the radial direction from the edge part of the base part 10, a front part of the straight part 12a, and the standing piece 11a side of the arm piece 11b. Are integrally formed with an arcuate portion 12b that connects the opposite end. As shown in FIG. 5 (a), the movable contact support base 1 in the present embodiment is provided with three spring portions 12, and the angles between the adjacent straight portions 12a in the orthogonal plane are all the same. Are equal (120 degrees in this embodiment). In addition, the angles between the adjacent straight portions 12a and the arm pieces 11b of the arm portion 11 in the orthogonal plane are all equal (60 degrees in this embodiment). Therefore, the arc-shaped portion 12b of each spring portion 12 has an arc shape whose center coincides with the base portion 10 and whose central angle is 60 degrees.

  Thus, in the micro electromechanical switch of this embodiment, since the base part 10 and the arm part 11 are connected by the spring part 12, the electric power consumed by the actuator 4 when moving the base part 10 is reduced. be able to. That is, in the micro electromechanical switch of this embodiment, when the base part 10 is moved to the fixed contact 3 side by the arm part 11, the base part 10 is pulled radially outward by the arm part 11, so that the movable contact 2 is fixed. In order to make contact with the contact 3, it is necessary to deform not only the arm portion 11 but also the base portion 10 by the actuator 4, but in the present embodiment, the spring portion 12 extends instead of the base portion 10. Therefore, the driving force that needs to be generated by the actuator 4 can be reduced. In addition, the shape of the spring part 12 is not limited to what is shown in FIG. 5, It can change in the range which does not deviate from the meaning of this invention.

  In the above, the fixed contact 3 is provided on the cover 6, but the fixed contact 3 is not necessarily provided on the cover 6. For example, as shown in FIG. 6A, the fixed contact 3 may be formed on a fixed contact support base 13 formed on the one surface side of the base substrate 5. Note that the fixed contact support 13 can be formed simultaneously with the formation of the movable contact support 1. In addition, as shown in FIG. 6B, the fixed contact 3 can be directly formed on the one surface of the base substrate 5. In addition, illustration of the cover 6 is abbreviate | omitted in FIG. 6 (a), (b).

  6A and 6B, for example, a sacrificial layer (not shown) is formed on the one surface side of the base substrate 5, and then the base of the fixed contact 3 is formed. A metal layer (not shown) is formed so as to cover the sacrificial layer, and thereafter, the metal layer is patterned into a desired shape using a photolithography technique and an etching technique, and finally the sacrificial layer is formed. It can be formed by removing.

(Embodiment 4)
As shown in FIGS. 7A and 7B, the microelectromechanical switch of this embodiment is mainly different from the third embodiment in the configuration of the movable contact support 1 and the actuator 4, and the other configurations are the same as those in the embodiment. 3 are the same as those in FIG. In FIG. 7A, the base substrate 5 and the cover 6 are not shown.

  The movable contact support base 1 in the present embodiment is different from that in the third embodiment in that the three arm portions 11 are each formed such that the middle part 11c of the arm piece 11b is wider than both end portions. The other configuration of the movable contact support 1 is the same as that of the third embodiment.

  Unlike the first embodiment, the actuator 4 in the present embodiment is of a hybrid type having a main drive means 4A using a piezoelectric effect and a sub drive means 4B using an electrostatic attractive force. As shown in FIGS. 7A and 7B, the main drive unit 4A includes a lower electrode 40a, a piezoelectric material portion 41, and an upper electrode 42a. This is described in the first embodiment. Since this corresponds to the actuator 4 described above, the description thereof is omitted.

  The sub-driving means 4B includes a movable electrode 40d formed on the fixed contact 3 side of the arm portion 11, that is, one surface side in the thickness direction of the arm piece 11b of the arm portion 11 (upper surface side in FIG. 7B), and a base portion 10 and a fixed electrode 45 arranged to overlap the movable electrode 40d in the thickness direction. The movable electrode 40d is formed on the middle part 11c of the arm piece 11b, and is electrically connected to the lower electrode 40a formed on the standing piece 11a side of the arm piece 11b. Therefore, in the actuator 4 in the present embodiment, the conductive pattern 40b is shared by the movable electrode 40d and the lower electrode 40a. In this case, the movable electrode 40d can be formed simultaneously with the lower electrode 40a, the conductor pattern 40b, and the connection portion 40c when the lower electrode 40a is formed as described in the first embodiment. Further, the surface of the movable electrode 40d opposite to the arm portion 11 side (the upper surface in FIG. 7B) is covered with the third insulating thin film 46. As a result, contact between the movable electrode 40d and the fixed electrode 45 is prevented.

  On the other hand, the fixed electrode 45 is formed not on the arm portion 11 but on the inner bottom surface 6 b of the cover 6. Accordingly, the cover 6 is formed with a through-hole 6d that allows the fixed electrode 45 to face the surface opposite to the inner bottom surface 6b (the upper surface in FIG. 7B). A through-hole wiring 9 is formed inside the through-hole 6d. The sub-driving unit 4B described above applies the predetermined driving voltage between the movable electrode 40d and the fixed electrode 45 to generate an electrostatic attractive force between the movable electrode 40d and the fixed electrode 45, thereby causing the arm portion 11 to move. Deform.

  In the microelectromechanical switch of the present embodiment described above, the movable contact 2 and the fixed contacts 3 are spaced apart from each other and the pair of fixed contacts 3 are disconnected when the actuator 4 is not driven. When closing the contact, first, the main drive means 4A of the actuator 4 is driven to move the base 10 to the fixed contact 3 side, and the movable contact 2 is brought into contact with the pair of fixed contact 3 and the dummy contact 8. Let Thereafter, the sub driving means 4B is driven to increase the contact pressure between the movable contact 2, the pair of fixed contacts 3 and the dummy contact 8. As described above, in the micro electromechanical switch of the present embodiment, the sub driving means 4B using electrostatic attraction is used to adjust the contact pressure between the movable contact 2 and the fixed contact 3, and the movable contact 2 The main drive means 4A using the piezoelectric effect is used for the movement toward the fixed contact 3 side. When opening the contacts, both the main drive means 4A and the sub drive means 4B of the actuator 4 may be stopped.

  According to the microelectromechanical switch of the present embodiment described above, in addition to the same effects as those of the third embodiment, the actuator 4 causes the arm drive 11 to deform using the deformation of the piezoelectric material section 41. 4A and sub-driving means 4B for deforming the arm portion 11 using electrostatic attraction force. When the electrostatic attraction force is utilized by moving the base portion 10 by the main driving device 4A. In comparison, the amount of displacement of the base 10 can be increased while keeping the power consumption of the actuator 4 low, so that the gap between the movable contact 2 and the fixed contact 3 can be widened to reduce signal leakage. On the other hand, the contact pressure between the movable contact 2 and the fixed contact 3 can be set to a desired value by the sub drive device 4B.

  By the way, in the micro electromechanical switch shown in FIG. 7A, the movable electrode 40d of the sub driving means 4B is provided on the arm piece 11b of the arm portion 11, but the position where the movable electrode 40d is provided is not limited to the arm portion 11. . For example, as shown in FIG. 8, you may provide in the arc-shaped part 12b of the spring part 12. As shown in FIG. In the micro electromechanical switch shown in FIG. 8, a wide portion 12c formed by forming a part of the arc-shaped portion 12b to be wide is provided, and a movable electrode 40d and a movable electrode 40d are provided on the fixed contact 3 side in the wide portion 12c. And a third insulating thin film 46 is formed. In addition, although illustration is abbreviate | omitted in FIG. 8, the movable electrode 40d is electrically connected to the lower electrode 40a by the conductor pattern formed in the shape over the arc-shaped part 12b and the arm piece 11b. Therefore, also in the micro electromechanical switch shown in FIG. 8, the conductive pattern 40b is shared by the movable electrode 40d and the lower electrode 40a. Although not shown in FIG. 8, the fixed electrode 45 is formed on the inner bottom surface 6 b of the cover 6 so as to overlap the movable electrode 40 d in the thickness direction of the base portion 10.

  Also in the micro electromechanical switch shown in FIG. 8 described above, the same effect as the micro electromechanical switch shown in FIGS. 7A and 7B can be obtained. In particular, according to the microelectromechanical switch shown in FIG. 8, since the wide portion 12c for forming the movable electrode 40d is formed on the spring portion 12, the movable electrode 40d is formed on the arm piece 11b as shown in FIG. Compared to the case shown in FIG. 7, since the area of the movable electrode 40d can be increased, if the drive voltage applied between the movable electrode 40d and the fixed electrode 45 is the same value, compared to that shown in FIG. The electrostatic attractive force generated between the movable electrode 40d and the fixed electrode 45 can be increased.

  7 shows an example in which the movable electrode 40d of the sub-driving unit 4B is formed on the arm portion 11, and FIG. 8 shows an example in which the movable electrode 40d is formed on the spring portion 12, but the movable electrode 40d is formed. The place to perform is not limited to the example shown in FIGS. 7 and 8, and it is only necessary to be formed on the fixed contact 3 side in the movable contact support 1.

The micro electromechanical switch of Embodiment 1 is shown, (a) is the top view which abbreviate | omitted one part, (b) is A1-A2 arrow sectional drawing of the figure (a), (c) is the figure (a) It is an A1-A3 arrow directional cross-sectional view of). It is an enlarged view of the site | part shown by P in Fig.1 (a). The micro electromechanical switch of Embodiment 2 is shown, (a) is a top view which abbreviate | omitted one part, (b) is B1-B2 arrow sectional drawing of the figure (a), (c) is the figure (a) Is a cross-sectional view taken along line B1-B3 in FIG. It is the top view which abbreviate | omitted some micro electromechanical switches of the other example same as the above. The micro electromechanical switch of Embodiment 3 is shown, (a) is a top view which abbreviate | omitted one part, (b) is C1-C2 arrow sectional drawing of the figure (a), (c) is the figure (a) It is a C1-C3 line arrow sectional view of). It is sectional drawing which abbreviate | omitted a part of micro electromechanical switch of the other example same as the above. The micro electromechanical switch of Embodiment 4 is shown, (a) is the top view which abbreviate | omitted one part, (b) is D1-D2 arrow sectional drawing of the figure (a). It is the top view which abbreviate | omitted some micro electromechanical switches of the other example same as the above. It is a disassembled perspective view of the micro electromechanical switch of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Movable contact support stand 2 Movable contact 3 Fixed contact 4 Actuator 4A Main drive means 4B Sub drive means 5 Base board 8 Dummy contact 10 Base part 10a Support part 10c Deformation part (peripheral part)
10d Empty space 11 Arm portion 12 Spring portion 40a Lower electrode 40d Movable electrode 41 Piezoelectric material portion 42a Upper electrode 45 Fixed electrode

Claims (8)

A base having a movable contact provided on one surface side in the thickness direction, one end connected to the base, and the other end fixed to the base substrate, and the base can be supported movably in the direction along the thickness direction. A movable contact support base provided with a plurality of flexible arm parts, a pair of fixed contacts arranged to face the movable contact on the one surface side of the base part, and a movable contact of the base part provided in each arm part A plurality of actuators that individually deform each arm portion in contact with both of the pair of fixed contacts;
Each arm part has the same shape and is arranged in a shape along the radial direction of a circle centering on the movable contact in a plane perpendicular to the thickness direction of the base part,
The number of arm parts is an integer multiple of 3,
A microelectromechanical switch characterized in that the angles between adjacent arm portions in the plane are all equal. A dummy contact that is brought into contact with the movable contact together with each of the fixed contacts,
The facing surfaces of the fixed contacts and the dummy contacts of the movable contacts are located on the same plane,
Each of the fixed contact and the dummy contact has a contact portion with the movable contact located on the same circumference around the movable contact in the plane, and the distance between the contact portions on the circumference is any. 2. The micro electromechanical switch according to claim 1, wherein the switches are equal.   3. The micro electromechanical switch according to claim 2, wherein each of the fixed contacts and the dummy contacts are disposed so as not to face any of the arm portions in the thickness direction of the base portion.   The micro electromechanical switch according to any one of claims 1 to 3, wherein the peripheral portion of the base portion where the movable contact is formed has a corrugated cross-sectional shape.   5. The micro electromechanical switch according to claim 4, wherein a space for reducing the rigidity of the base portion is formed in the peripheral portion.   The micro electromechanical switch according to any one of claims 1 to 3, wherein one end of each arm part is integrally connected to the base part via a spring part having elasticity.   The actuator includes: a lower electrode formed on at least one of the fixed contact side and the opposite side of the arm portion; a piezoelectric material portion formed on the opposite side of the lower electrode to the arm portion side; An upper electrode formed on the opposite side of the piezoelectric material portion from the lower electrode side, and applying the predetermined drive voltage between the lower electrode and the upper electrode to deform the piezoelectric material portion to The micro electromechanical switch according to claim 1, wherein the micro electro mechanical switch is deformed. The actuator includes a lower electrode formed on at least one of the fixed contact side and the opposite side in the arm portion, a piezoelectric material portion formed on the opposite side of the lower electrode from the arm portion side, and the piezoelectric material An upper electrode formed on the side opposite to the lower electrode side, and applying a predetermined driving voltage between the lower electrode and the upper electrode to deform the piezoelectric material portion to deform the arm portion. Driving means;
A movable electrode formed on the movable contact support base on the fixed contact side, and a fixed electrode arranged to overlap the movable electrode in the thickness direction of the base portion, and a predetermined gap is provided between the movable electrode and the fixed electrode. Sub-driving means for moving the platform to the pair of fixed contacts by applying a driving voltage to generate an electrostatic attractive force between the movable electrode and the fixed electrode is provided. The micro electromechanical switch according to any one of claims 1 to 6.

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