WO2005052966A1

WO2005052966A1 - Displacement element

Info

Publication number: WO2005052966A1
Application number: PCT/JP2004/013782
Authority: WO
Inventors: Masanobu Nomura
Original assignee: Murata Manufacturing Co., Ltd.
Priority date: 2003-11-27
Filing date: 2004-09-22
Publication date: 2005-06-09
Also published as: JPWO2005052966A1; JP4534988B2

Abstract

A displacement element having a beam in a state of being supported at its opposite ends and having the excellent controllability of an absolute position in an initial state. In the beam (12) formed such that a plurality of functional material layers (13 to 16) are stacked on each other in the thickness direction, a thickness adding member (27) is disposed at the center part (26) of the effective deflection portion (25) thereof, and the effective deflection portion (25) is made symmetrical with respect to the perpendicular bisector face (28) of a length between first fulcrum (23) and a second fulcrum (24). The first one side deflection portion (30) is made symmetrical with respect to the perpendicular bisection face (31) of a length between the first fulcrum (23) and a first inner end (29) and the second one side deflection portion (33) is made symmetrical with respect to the perpendicular bisector face (34) of a length between the second fulcrum (24) and a second inner end (32).

Description

Displacement element

Technical field

The present invention relates to a displacement element, and more particularly to a displacement element having a structure in which a plurality of functional material layers having different material forces are stacked in a thickness direction, and including a beam in a doubly supported state. .

Background art

[0002] Displacement elements of interest to the present invention include, for example, the one described in Japanese Patent Application Laid-Open No. 9-63890 (Patent Document 1). Patent Document 1 describes a displacement element that constitutes a variable capacitance element. Some of the displacement elements described in Patent Document 1 have a structure having a cantilevered beam, and others have, for example, a structure having a double-supported beam 1 as shown in FIG.

[0003] Referring to FIG. 15, beam 1 includes an insulator layer 2 having an SiO force and one main surface of insulator layer 2 and

2

On the other hand, it has a structure in which conductor layers 3 and 4 respectively formed on the main surface are laminated in the thickness direction. The beam 1 is in a double-supported state in which first and second ends 5 and 6 in the longitudinal direction are supported by first and second support portions 7 and 8, respectively.

[0004] The beam 1 provides a variable-side electrode in the variable capacitance element. Although not shown, the fixed-side electrode of the variable capacitance element is provided at a position facing the beam 1 via the support portions 7 and 8. Therefore, in order to accurately and accurately control the capacitance value of the variable capacitance element or to improve the temperature characteristics of the capacitance value, the shape of the beam 1 (radial state) in the initial state has good reproducibility. It is important that the beam 1 is stable, more specifically, that the beam 1 has excellent linearity.

[0005] In this regard, since the beam 1 has a laminated structure that is symmetrical with respect to the insulating layer 2, the stresses generated on the front and back surfaces of the insulating layer 2 cancel each other out, and therefore, in the initial state. Therefore, the beam 1 does not easily warp.

[0006] In order to completely prevent the warpage of the beam 1 by the above-described symmetrical structure, the conductor layers 3 and 4 must have at least a film thickness, an internal stress, an elastic constant, And the coefficients of thermal expansion must be perfectly matched, and in each of the insulator layer 2 and the conductor layers 3 and 4, the forces that need to be completely homogenous in the thickness direction of the layers. Meeting the conditions is very difficult.

[0007] Therefore, at present, it is unavoidable that a warp as shown in FIG. 16 or FIG. 17 occurs in the initial state, that is, in the beam 1 immediately after fabrication. In FIG. 16, the beam 1 is warped upwardly, as indicated by the arrow 9, and the initial absolute position of the center of the beam 1 in the initial state is displaced upward. On the other hand, in FIG. 17, the beam 1 is warped in a downwardly curved shape as shown by the arrow 10, and the absolute position of the central portion of the beam 1 in the initial state is displaced downward. In addition, warpage as described above may occur in the beam 1 due to a temperature change.

[0008] Further, the front and back symmetrical structure given to the beam 1 has a problem that the degree of freedom in designing the beam 1 is reduced as described below.

[0009] For example, in the beam 1 shown in Fig. 15, the conductor layers 3 and 4 are formed on the front and back of the insulator layer 2, respectively, thereby realizing a total of three layers of front and back symmetric structures. If one functional material layer is to be added, this functional material layer must be added to each of the front and back surfaces, so that a total of five front and back symmetric structures must be used.

[0010] However, among the functional material layers added as described above, those on either side of the front and back sides are formed merely for realizing a front and back symmetric structure. Therefore, the number of manufacturing steps for forming the functional material layer is increased, which causes a problem that the cost is increased.

[0011] Further, as described above, making the film thickness, the internal stress, the elastic constant, and the coefficient of thermal expansion completely identical on each of the front and back sides of the insulator layer 2 requires a total of three layers of front and back symmetric structures. In comparison, it is much more difficult in the case of a five-layer symmetric structure.

[0012] For example, with respect to the structure shown in FIG. 15, in order to realize a symmetrical structure, the plane pattern of the conductor layer 3 and the plane pattern of the conductor layer 4 are also symmetric. There must be. Depending on the functions required of the beam 1, the conductor layer 3 and the conductor layer 4 may not be able to be formed into a symmetrical shape while the beam 1 warps. May not be solved.

Patent Document 1: JP-A-9-63890 Disclosure of the invention

Problems to be solved by the invention

[0013] An object of the present invention is to provide a displacement element that can solve the above-described problems.

Means for solving the problem

[0014] The present invention provides a beam having a structure in which a plurality of functional material layers having different material strengths are laminated in the thickness direction, and a first and a second beam in a longitudinal direction of the beam so that the beam is held at both ends. First and second support portions respectively supporting the second end portion, and a first fulcrum and a second support portion of the beam by the first support portion to cause displacement of the beam in the thickness direction. And a driving means for electrically driving the effective radius portion between the second fulcrum and the second fulcrum. In order to solve the problem, the following features are provided.

[0015] That is, a thickness-providing member for increasing the thickness of the central portion in the longitudinal direction of the effective radius portion to be greater than other portions is disposed. Further, the effective radius portion has a symmetrical structure with respect to a perpendicular bisector between the first fulcrum and the second fulcrum, and the first fulcrum and the first member of the thickness imparting member in the effective radius portion. A first radial portion between the first inner end located at the end of the fulcrum side has a symmetrical structure with respect to a perpendicular bisector of the first fulcrum and the first inner end, And, in the effective radius portion, the second one-side radius portion between the second fulcrum and the second inner end located at the second fulcrum-side end of the thickness imparting member is a second fulcrum and a second fulcrum. It has a symmetric structure with respect to a perpendicular bisector with the second inner end.

[0016] In the present invention, the effective radius portion may have a symmetric structure with respect to a perpendicular bisector of the first free end and the second free end, which are each end in the width direction. preferable.

[0017] Further, it is preferable that the thickness imparting member is disposed so as to extend over the entire area between the first free end and the second free end which are each end in the width direction of the effective radius portion. .

[0018] The displacement element according to the present invention has several embodiments, particularly regarding the driving means.

In the first embodiment, the displacement element constitutes a piezoelectric drive type displacement element, at least one of the plurality of functional material layers is a piezoelectric layer made of a piezoelectric material, and the driving means is Means for distorting the piezoelectric layer based on the piezoelectric effect is provided. [0020] In the second embodiment, the displacement element constitutes an electromagnetically driven displacement element, and at least one of the plurality of functional material layers is a conductor layer made of a conductor. Comprises means for generating lines of magnetic force by passing an electric current through the conductor layer, and means for generating an electromagnetic force in the conductor layer to externally apply a magnetic field to the conductor layer so that the effective radius is radiused. ing.

In the third embodiment, the displacement element constitutes an electrostatic drive type displacement element, and at least one of the plurality of functional material layers is a conductive layer made of a conductive material. The means comprises: a fixed conductor fixedly provided at a position separated from the conductor layer by an air layer; and means for applying a voltage between the conductor layer and the fixed conductor. By applying a voltage between the layer and the fixed conductor, an electrostatic attraction is generated between the conductor layer and the fixed conductor, whereby the effective radius is bent. .

The displacement element according to the present invention is advantageously used, for example, for forming a variable capacitance element. In this case, the first electrode provided on the effective radius portion including the thickness imparting member and the first electrode are fixedly provided at a position separated by an air layer so as to form a capacitance with respect to the first electrode. And a second electrode, wherein the capacitance is changed by the radius of the effective radius.

The invention's effect

[0023] According to the displacement element of the present invention, the thickness, internal stress, elastic constant, coefficient of thermal expansion, and the like of the plurality of functional material layers provided on the beam are controlled so as to have a symmetrical structure. In the longitudinal direction of the first one-sided radius portion between the first fulcrum and the first inner end located at the first fulcrum-side end of the thickness imparting member in the effective radius portion of the beam. The warpage and the warpage in the longitudinal direction of the second one-sided radius portion between the second fulcrum and the second inner end located at the second fulcrum-side end of the thickness imparting member, It can be made symmetrical. Therefore, the absolute position of the central portion of the effective radius in the initial state can be controlled stably and constantly.

[0024] As a result, the amount of displacement of the effective radius portion caused by the driving means can be stabilized, so that a displacement element having excellent absolute position controllability can be obtained. When applied, accurate and highly accurate capacity control is performed. Can be.

[0025] Further, the displacement element according to the present invention does not require a front-back symmetric structure, so that the degree of freedom in design can be increased.

[0026] In the present invention, the effective radius portion also has a symmetrical structure with respect to a perpendicular bisector of the first free end and the second free end, which are each end in the width direction. In addition, since the variation of the absolute position due to the warp of the effective radius portion in the width direction can be prevented, more accurate absolute position controllability can be obtained.

[0027] In the present invention, the thickness imparting member is arranged so as to extend over the entire area between the first free end and the second free end, which are each end in the width direction of the effective radius portion. By the rib effect provided by the thickness imparting member, the effective radius portion can be warped in the width direction and can be made thicker.

Brief Description of Drawings

[FIG. 1] FIG. 1 is for describing a first embodiment of a configuration of a displacement element according to the present invention except for driving means, and FIG. 1 (a) is a plan view of a displacement element 11; It is a figure, (b) is an end view of the cut part along cut surface BB of (a).

[FIG. 2] FIG. 2 is a view corresponding to FIG. 1 (b), showing a tendency of warpage occurring in an initial state of the beam 12 provided in the displacement element 11 shown in FIG.

FIG. 3 is a diagram corresponding to FIG. 2 and shows a tendency of warpage in another mode.

FIG. 4 is a diagram corresponding to FIG. 1 (b), showing a second embodiment of the configuration of the displacement element according to the present invention except for the driving means.

FIG. 5 is a view corresponding to FIG. 1 (a), showing a third embodiment of the configuration of the displacement element according to the present invention except for the driving means.

FIG. 6 is a diagram corresponding to FIG. 1 (a), showing a fourth embodiment of the configuration of the displacement element according to the present invention except for the driving means.

[FIG. 7] FIG. 7 is a view for explaining a first embodiment of a driving means of the displacement element according to the present invention. (A) is a plan view of the displacement element 51, () Is an end view of the cut portion along the cut surface BB of (a).

FIG. 8 is a diagram corresponding to FIG. 7 (b) for explaining the operation of the displacement element 51 shown in FIG. 7; It is.

FIG. 9 is a view corresponding to FIG. 7B for explaining another operation of the displacement element 51 shown in FIG. 7.

FIG. 10 is a view for explaining a second embodiment of the driving means of the displacement element according to the present invention, wherein (a) is a plan view of the displacement element 81 and (b) FIG. 3A is an end view of a cut section along a cut plane B-B in FIG.

FIG. 11 is a view for explaining a third embodiment of the driving means of the displacement element according to the present invention, wherein (a) is a plan view of the displacement element 111 and (b) (A) is an end view of the cut portion along the cut surface BB of (a).

FIG. 12 is a plan view of a displacement element 141 for explaining a variable capacitance element as a preferred application example of the displacement element according to the present invention.

[FIG. 13] FIG. 13 is a sectional end view taken along the section plane X—X in FIG.

[FIG. 14] FIG. 14 is an end view of a cut portion along a cut surface YY of FIG.

FIG. 15 is a cross-sectional view schematically showing a conventional displacement element provided with a doubly supported beam 1 of interest to the present invention.

[FIG. 16] FIG. 16 is a view corresponding to FIG. 15, showing warpage that may occur in the initial state of the beam 1 shown in FIG.

[FIG. 17] FIG. 17 is a view corresponding to FIG. 15 and showing another form of warpage that may occur in the initial state of the beam 1 shown in FIG.

Explanation of symbols

11, 11a, lib, 11c, 51, 81, 111, 141 Displacement element

12, 52, 82, 112, 144, 145 beams

13— 16, 41— 45 Functional material layer

17, 18, 57, 58, 87, 88, 116, 117, 150, 151 end

19, 20, 59, 60, 89, 90, 118, 119, 152, 153 Support

23, 24, 63, 64, 93, 94, 122, 123, 155, 156

25, 65, 95, 124, 157, 160 Effective radius

26, 66, 96, 125, 158, 161 Central 27, 67, 97, 126, 159 Thickening member

28, 31, 34, 37, 68, 71, 74, 77, 98, 101, 104, 107, 127, 130, 133, 136, 162, 165, 168, 171 Vertical bisector

29, 32, 69, 72, 99, 102, 128, 131, 163, 166 Inner end

30, 33, 70, 73, 100, 103, 129, 132, 164, 167 Unilateral radius

35, 36, 75, 76, 105, 106, 134, 135, 169, 170

53, 146 buffer layer

54, 147 Lower electrode layer

55, 148 Piezoelectric layer

56, 149 Upper electrode layer

83, 113 Insulator layer

84, 114 conductor layer

138, 177 Air layer

174, 175, 178 electrodes

BEST MODE FOR CARRYING OUT THE INVENTION

FIGS. 1 to 3 illustrate a first embodiment of a displacement element according to the present invention except for a driving unit. Here, FIG. 1 (a) is a plan view of the displacement element 11, and FIG. 1 (b) is an end view of a cut portion along a cut surface BB of FIG. 1 (a). 2 and 3 are diagrams corresponding to FIG. 1 (b), showing the tendency of the beam 12 provided in the displacement element 11 shown in FIG. 1 to be warped in an initial state.

Referring to FIG. 1, the displacement element 11 includes a beam 12, and the beam 12 has a structure in which a plurality of functional material layers 13, 14, 15, and 16 having different material forces are stacked in a thickness direction. have. Here, it should be noted that the beams 12 do not need to be particularly symmetrical.

Further, the displacement element 11 includes first and second support members for supporting the first and second end portions 17 and 18 in the longitudinal direction of the beam 12 so as to hold the beam 12 in a double-supported state. Parts 19 and 20 are provided. In this embodiment, each of the first and second support portions 19 and 20 is provided by a part of a substrate 22 provided with a through-hole 21 as well shown in FIG. Has been obtained.

Although not specifically shown, the displacement element 11 is configured to cause the beam 12 to be displaced in the thickness direction, so that the first fulcrum 23 and the second fulcrum 23 of the beam 12 Drive means for electrically driving the effective radius portion 25 between the second fulcrum 24 of the support portion 20 and the second fulcrum 24.

Further, the displacement element 11 has the following characteristic configuration.

[0035] At a central portion 26 in the longitudinal direction of the effective radius portion 25, a thickness imparting member 27 for increasing the thickness of the central portion 26 to be greater than other portions is disposed.

The effective radius portion 25 has a symmetrical structure with respect to a vertical bisector 28 between the first fulcrum 23 and the second fulcrum 24! / Puru.

[0037] In the effective radius portion 25, a first one-side radius between the first fulcrum 23 and the first inner end 29 located at the first fulcrum 23-side end of the thickness imparting member 27 is set. The only part 30 has a symmetrical structure with respect to a perpendicular bisector 31 between the first fulcrum 23 and the first inner end 29.

[0038] On the other hand, in the effective radius portion 25, a second one-side radius between the second fulcrum 24 and the second inner end 32 located at the second fulcrum 24 side end of the thickness imparting member 27. The only portion 33 also has a symmetrical structure with respect to the perpendicular bisector 34 between the second fulcrum 24 and the second inner end 32.

[0039] Further, as is well shown in Fig. 1 (a), the effective radius portion 25 is formed by a first free end 35 and a second free end 36, which are respective ends in the width direction. It also has a symmetrical structure with respect to the perpendicular bisector 37 (corresponding to the cutting plane BB).

[0040] The thickness imparting member 27 is disposed so as to extend over the entire area between the first free end 35 and the second free end 36, which are each end in the width direction of the effective radius portion 25. I have.

In the displacement element 11 having the above configuration, the warpage of the beam 12 in the initial state or the warpage caused by a temperature change has a tendency as shown in FIG. 2 or FIG.

[0042] Different internal stresses occur between the functional material layers 13-16 due to the manufacturing conditions of the functional material layers 13-16 constituting the beam 12, and the functional material layers 13-16 due to temperature changes. When thermal stress is generated between the functional material layers 13-16 due to the difference in the thermal expansion coefficient of the materials constituting the first and second beams, as shown in FIG. 2 or FIG. Warpage occurs at the unilateral radius 30 and 33 (see Fig. 1). Actually, Figure 2 or Warpage also occurs in the width direction of the beam 12 (direction perpendicular to the paper surface in FIGS. 2 and 3), which is caused only by the warpage in the longitudinal direction of the beam 12 as shown in FIG.

The degree of warpage that occurs as described above is determined by the thickness of the functional material layers 13 to 16 constituting the beam 12, the magnitude of the internal stress, the elastic constant, the coefficient of thermal expansion, and the like. On the other hand, in the case of this embodiment, since the thickness imparting member 27 arranged at the central portion 26 of the effective radius portion 25 is sufficiently thick, the warpage is the first piece in both the longitudinal direction and the width direction. The lateral radius 30 and the second lateral radius 33 will occur substantially independently of each other.

[0044] As described above, when warpage occurs in each of the first one-side radius portion 30 and the second one-side radius portion 33, the first and second one-side radius portions 30 and 33 become: Since each has a symmetrical structure with respect to the perpendicular bisectors 31 and 34, the direction and degree of warpage in the longitudinal direction are symmetric on both sides of each of the perpendicular bisectors 31 and 34.

The effective radius portion 25 also has a symmetrical structure with respect to a perpendicular bisector 28 between the first fulcrum 23 and the second fulcrum 24, so that the warp in the longitudinal direction Depending on the direction and the degree of, both sides of the perpendicular bisector 28 are also symmetric.

Then, as described above, the direction and degree of warpage in the longitudinal direction of each of the first and second one-side radius portions 30 and 33 are determined by the respective vertical bisectors 31 and 34 Since it is symmetrical on both sides and also symmetrical on both sides of the perpendicular bisector 28, the absolute position of the central portion 26 in the initial state can always be constant.

[0047] In other words, even if the thickness, the magnitude of the internal stress, the elastic constant, the coefficient of thermal expansion, and the like of the functional material layers 13 to 16 constituting the beam 12 are not controlled, they are shown in FIGS. The height position of the first and second inner ends 29 and 32 is always the same as the height position of the first and second fulcrums 23 and 24 so that the comparison force with the position of the broken line 38 can be understood. It can be controlled so that

[0048] Regarding the above, as in this embodiment, the effective radius portion 25 is a perpendicular bisector of the first free end 35 and the second free end 36, which are each end in the width direction. If the surface 37 also has a symmetric structure, the symmetry can be further improved with respect to the above-described warpage in the longitudinal direction. can do.

[0049] Regarding the dimension of the thickness imparting member 27, the dimension in the thickness direction is a thicker force. The dimension in the longitudinal direction (dimension in the longitudinal direction of the beam 12) is shorter, and the dimension in the width direction (beam As the dimension of the beam 12 in the width direction is greater than or equal to the dimension of the beam 12 in the width direction, the position controllability described above can be further improved.

FIG. 4 is a view, corresponding to FIG. 1 (b), showing a second embodiment of the configuration of the displacement element according to the present invention except for the driving means. In FIG. 4, elements corresponding to the elements shown in FIG. 1 (b) are denoted by the same reference numerals, and redundant description will be omitted.

In the displacement element 11a shown in FIG. 4, five functional materials, which are more than the four functional material layers 13-16 shown in FIG. It is characterized by having layers 41-45. As can be seen from this embodiment, the number of functional material layers that provide the laminated structure in the beam is not particularly limited.

FIG. 5 is a view, corresponding to FIG. 1 (a), showing a third embodiment of the configuration of the displacement element according to the present invention except for the driving means. In FIG. 5, elements corresponding to the elements shown in FIG. 1 (a) are denoted by the same reference numerals, and redundant description will be omitted.

The displacement element l ib shown in FIG. 5 is different from the displacement element 11 shown in FIG. 1A, for example, in that the beam 12, the functional material layers 13 to 16 (for the functional material layers 15 and 16, It is not shown because it is hidden under the functional material layer 14.) It is significant to clarify that the planar shape of each of the through hole 21 and the thickness imparting member 27 can be arbitrarily changed.

FIG. 6 is a view, corresponding to FIG. 1 (a), showing a fourth embodiment of the configuration of the displacement element according to the present invention except for the driving means. In FIG. 6, elements corresponding to the elements shown in FIG. 1 (a) are denoted by the same reference numerals, and redundant description will be omitted.

The displacement element 11c shown in FIG. 6 is characterized by having a cross-shaped beam 12. In this way, by forming the beam 12 in a cross shape, the first and second ends 17 and 18 of the beam 12, the first and second support portions 19 and 20 supporting these, the first and second Two unilateral radii 30 and 33 and two perpendicular bisectors 28, 31 and 34 will each be provided.

FIGS. 7 to 9 show a first embodiment of the driving means of the displacement element according to the present invention. It is for explaining the state. Here, FIG. 7 (a) is a plan view of the displacement element 51, and FIG. 7 (b) is a cross-sectional end view along the cut plane BB of FIG. 7 (a). 8 and 9 are views corresponding to FIG. 7B for explaining the operation of the displacement element 51 shown in FIG.

The displacement element 51 constitutes a piezoelectric drive type displacement element, and has a basic configuration common to the displacement element 11 shown in FIG.

[0058] The displacement element 51 includes a beam 52. The beam 52 is, for example, a buffer layer 53 that also has an Al 2 O force.

twenty three

For example, it has a structure in which a lower electrode layer 54 made of Pt, for example, a piezoelectric layer 55 made of PZT (lead zirconate titanate) and an upper electrode layer 56 made of, for example, A1 are laminated in the thickness direction. The upper electrode layer 56 is formed by being divided into first, second and third upper electrode layers 56a, 56b and 56c.

[0059] The above-described buffer layer 53, electrode layers 54 and 56, and piezoelectric layer 55 may have a material strength other than the materials described above. For example, as the material of the buffer layer 53, TiO

2

Or electrode layer 54 and ZrO

2 Au or Ag may be used as the material of Z or 56, and ZnO, LiTaO

Three

Alternatively, LiNbO may be used.

Three

Further, in order to increase the displacement amount based on the piezoelectric effect described later, it is desirable that the total thickness of the buffer layer 53 and the lower electrode layer 54 be substantially equal to the thickness of the piezoelectric layer 55. The upper electrode layer 56 is desirably formed thin using a material having high elasticity.

[0061] The displacement element 51 also includes first and second ends 57 and 58, which support the longitudinal direction of the beam 52, respectively, so as to hold the beam 52 as described above. Second supports 59 and 60 are provided. In this embodiment, as shown in FIG. 7 (a), each of the first and second support portions 59 and 60 is provided with a through-hole 61 provided on a substrate 62 made of, for example, S. Given by the department.

[0062] Such a displacement element 51 is formed by distorting the piezoelectric layer 55 based on the piezoelectric effect, so that the first support 63 and the second support 60 of the first support 59 in the beam 52 are provided. The effective radius 65 between the second fulcrum 64 and the second fulcrum 64 is radiused, so that the beam 52 Displacement occurs in the thickness direction. At a central portion 66 in the longitudinal direction of the effective radius portion 65, a thickness imparting member 67 made of, for example, Si is arranged to make the central portion 66 thicker than other portions.

[0063] The effective radius portion 65 has a symmetric structure with respect to a perpendicular bisector 68 between the first fulcrum 63 and the second fulcrum 64.

Further, the first fulcrum 63 and the first fulcrum 6 of the thickness imparting member 67 in the effective radius portion 65

The first one-side radius portion 70 between the first inner end 69 located at the end on the third side is

It has a symmetrical structure with respect to a perpendicular bisector 71 between 3 and the first inner end 69.

On the other hand, the second fulcrum 64 and the second fulcrum 6 of the thickness imparting member 67 in the effective radius portion 65

The second one-sided radius 73 between the second inner end 72 located at the fourth end is also symmetric with respect to the perpendicular bisector 74 between the second fulcrum 64 and the second inner end 72. It has a structure.

[0066] Further, as is well shown in Fig. 7 (a), the effective radius portion 65 is formed by a first free end 75 and a second free end 76 which are each end in the width direction. It also has a symmetric structure with respect to the perpendicular bisector 77 (corresponding to the cutting plane BB).

[0067] The thickness imparting member 67 is disposed so as to extend over the entire area between the first free end 75 and the second free end 76, which are each end in the width direction of the effective radius portion 65. I have.

[0068] Further, an extraction electrode 78 is electrically connected to the lower electrode layer 54 provided on the beam 52, and the end of the extraction electrode 78 is formed on the substrate 62 as shown in FIG. It is formed so as to be exposed to.

[0069] Further, an extraction electrode 79 is electrically connected to the first and second upper electrode layers 56a and 56b located at both ends of the upper electrode layer 56. The extraction electrode 80 is electrically connected to the third upper electrode layer 56c located at the center. The pattern of each of the extraction electrodes 79 and 80 is designed so that the symmetry of each of the vertical bisectors 68, 71, 74, and 77 described above is not impaired, and all are ensured. I have.

Next, an example of a method for manufacturing the displacement element 51 will be described.

First, a substrate 62 that is also made of S is prepared. At this stage, the through hole 61 is not formed in the substrate 62.

Next, an Al 2 O 3 film serving as the buffer layer 53 is formed on the substrate 62 by sputtering or vapor deposition. It is formed on the entire surface by a method. Next, a Pt film to be the lower electrode layer 54 and the extraction electrode 78 is formed on the entire surface by a method such as sputtering or vapor deposition. At this time, A1 of the Pt film

2 To improve adhesion to o film, form a film with Ti equivalent before forming Pt film

Three

You can do it.

Next, a PZT film to be the piezoelectric layer 55 is formed on the entire surface by a method such as MOCVD or sputtering. Here, it is desirable that the PZT be c-axis oriented in a direction perpendicular to the substrate surface.

Next, an A1 film to be the upper electrode layer 56 and the extraction electrodes 79 and 80 is formed by a method such as lift-off.

Next, the above-described PZT film, Pt film, and AlO film are masked through a resist mask.

twenty three

By applying a method such as on-milling, processing is performed so that the piezoelectric layer 55, the lower electrode layer 54, and the buffer layer 53 are obtained. Next, a part of the extraction electrode 78 is exposed by curling the piezoelectric layer 55 using a method such as ion milling through a resist mask.

Next, a through hole 61 is formed on the substrate 62 from the back side by applying a method such as RIE through a resist mask. At this time, the thickness providing member 67 is provided by a part of the substrate 62.

[0077] As described above, the displacement element 51 can be obtained.

Next, the operation of the displacement element 51 will be described.

[0079] The effective radius portion 65 of the beam 52 provided in the displacement element 51 has a symmetric structure as described above, and thus is the same as that described with reference to Figs. For the reason, in the initial state immediately after the fabrication, even if warpage as shown in FIG. 2 or FIG. 3 occurs, the height positions of the first and second inner ends 69 and 72 are changed to the first and second fulcrum. It can be controlled to always be the same as the 63 and 64 height positions.

In the above state, a voltage is applied between the extraction electrode 78 connected to the lower electrode layer 54 and the extraction electrode 79 connected to the first and second upper electrode layers 56a and 56b in the upper electrode layer 56. When voltage is applied, distortion occurs in the portion of the piezoelectric layer 55 located between the lower electrode layer 54 and the first and second upper electrodes 56a and 56b due to the inverse piezoelectric effect.

As a result, assuming that the generated piezoelectric stress acts in the tensile direction, the effective radius portion 65 In the initial state, as shown in FIG. 2, it is curved as shown in FIG. 8, while when initially in the state shown in FIG. 3, it is as shown in FIG. 9. Bends to Thus, as shown in FIGS. 8 and 9, the central portion 66 of the effective radius portion 65 of the beam 52 is displaced upward. Here, the amount of displacement can be controlled by the height of the voltage applied between the extraction electrodes 78 and 79.

On the other hand, when a voltage is applied between the extraction electrode 78 connected to the lower electrode layer 54 and the I output electrode 80 connected to the central third upper electrode layer 56c in the upper electrode layer 56, the piezoelectric material Distortion occurs in the portion of the layer 55 located between the lower electrode layer 54 and the third upper electrode layer 56c due to the inverse piezoelectric effect. As a result, the central portion 66 of the effective radius portion 65 of the beam 52 is displaced downward contrary to the state shown in FIG. 8 or FIG.

As described above, according to the displacement element 51, the absolute position of the central portion 66 of the effective radius portion 65 of the beam 52 in the initial state can be controlled to be constant, so that a voltage is applied to the piezoelectric layer 55. As a result, the central portion 66 of the effective radius portion 65 can be displaced by a predetermined amount, and a piezoelectrically-driven displacement element having good absolute position controllability can be realized.

FIG. 10 is for describing a second embodiment of the driving means of the displacement element according to the present invention. Here, FIG. 10 (a) is a plan view of the displacement element 81, and FIG. 10 (b) is an end view of a cut portion along the cut surface BB of FIG. 10 (a).

The displacement element 81 constitutes an electromagnetically driven displacement element, and has a basic configuration common to the displacement element 11 shown in FIG.

[0086] The displacement element 81 includes a beam 82. The beam 82 includes, for example, an insulator layer 83 that also has a SiO force.

2

For example, it has a structure in which A1 conductive layers 84 are stacked in the thickness direction. Leading electrodes 85 and 86 are connected to each end of the conductor layer 84.

[0087] The displacement element 81 also includes first and second ends 87 and 88 that support the longitudinal direction of the beam 82, respectively, so that the beam 82 is held in a double-supported state. Second supports 89 and 90 are provided. In this embodiment, as is well shown in FIG. 10 (a), each of the first and second support portions 89 and 90 is provided with a through-hole 91, for example, a substrate 92 having a Si force. Given by the department.

[0088] Such a displacement element 81 is connected to the first support portion of the beam 82 by electromagnetic driving described later. The effective radius 95 between the first fulcrum 93 by the 89 and the second fulcrum 94 by the second support 90 is deflected, whereby the beam 82 is displaced in the thickness direction. Occurs. At a central portion 96 in the longitudinal direction of the effective radius portion 95, a thickness providing member 97, for example, S, for increasing the thickness of the central portion 96 than other portions is disposed.

[0089] The effective radius portion 95 has a symmetric structure with respect to a perpendicular bisector 98 between the first fulcrum 93 and the second fulcrum 94. In particular, with respect to the conductor layer 84, the conductor layer 84 is formed on the central portion 96 of the effective radius 95, and the extraction electrodes 85 and 86 are symmetrical with respect to the vertical bisector 98 in the longitudinal direction. It extends.

[0090] In the effective radius portion 95, a first unilateral radius portion 100 between the first fulcrum 93 and the first inner end 99 located at the end of the thickness imparting member 97 on the first fulcrum 93 side. Has a symmetrical structure with respect to a perpendicular bisector 101 between the first fulcrum 93 and the first inner end 99.

On the other hand, in the effective radius portion 95, a second one-side radius between the second fulcrum 94 and the second inner end 102 located at the second fulcrum 94 side end of the thickness imparting member 97. The only portion 103 also has a symmetrical structure with respect to the perpendicular bisector 104 between the second fulcrum 94 and the second inner end 102.

[0092] Further, as is well shown in Fig. 10 (a), the effective radius portion 95 is formed by a first free end 105 and a second free end 106, which are each end in the width direction. It also has a symmetrical structure with respect to the perpendicular bisector 107 (corresponding to the cutting plane BB).

[0093] Further, the thickness imparting member 97 is disposed so as to extend over the entire area between the first free end 105 and the second free end 106, which are each end in the width direction of the effective radius portion 95. I have.

Next, an example of a method for manufacturing the displacement element 81 will be described.

[0095] First, a substrate 92 that also contains S is prepared. At this stage, the through hole 91 is not formed in the substrate 92.

[0096] Next, an SiO film to be the insulator layer 83 is formed on the substrate 92 by thermal oxidation or sputtering.

2

After being formed on the entire surface by the method, the insulator layer 83 is formed by wet etching. Next, an A return to be the conductor layer 84 is formed by a method such as lift-off.

Next, a through-hole 91 is formed on the substrate 92 from the back side by applying a method such as RIE through a resist mask. At this time, the thickness applying member 97 is attached to a part of the substrate 92. To be given.

[0098] As described above, the displacement element 81 can be obtained.

Next, an operation of the displacement element 81 will be described.

[0100] First, even in the displacement element 81, the symmetrical structure of the effective radius portion of the beam 82 and the symmetrical structure of each of the first and second one-side radius portions 100 and 103 are ensured. Therefore, the absolute position of the central portion 96 of the effective radius portion 95 in the initial state can always be kept constant.

In such a state, first, a permanent magnet or an electromagnet is arranged on the side of the beam 82 so that a magnetic field is applied in the longitudinal direction of the effective radius portion 95 of the beam 82. Here, when an electric current is applied to the conductor layer 84 through the extraction electrodes 85 and 86, magnetic lines of force are generated, and the conductor layer 84 on the central portion 96 of the effective radius portion 95 receives electromagnetic force and receives an effective radius. The central part 96 is displaced, thereby displacing the absolute position of the central part 96 upward or downward. Here, the amount of displacement can be controlled by the magnitude of the current flowing through the conductor layer 84.

[0102] As described above, according to the displacement element 81, the absolute position of the central portion 96 of the effective radius portion 95 of the beam 82 in the initial state can be controlled to be constant, so that the conductive layer 84, Further, the central portion 96 of the effective radius portion 95 can be displaced by a predetermined amount, and an electromagnetically driven displacement element with good absolute position control can be realized.

FIG. 11 is for describing a third embodiment of the driving means of the displacement element according to the present invention. Here, FIG. 11 (a) is a plan view of the displacement element 111, and FIG. 11 (b) is an end view of a cut portion along the cut surface BB of FIG. 11 (a).

The displacement element 111 constitutes an electrostatic drive type displacement element, and has a basic configuration common to the displacement element 11 shown in FIG. The displacement element 111 includes a beam 112. The beam 112 has a thickness of, for example, an insulator layer 113 made of SiO and a conductive layer 114 made of A1.

2

It has a structure laminated in the direction. An extraction electrode 115 is connected to the conductor layer 114.

[0105] The displacement element 111 also includes first and second ends 116 and 117 in the longitudinal direction of the beam 112, respectively, so as to hold the beam 112 as described above. Second supports 118 and 119 are provided. In this embodiment, this is better illustrated in FIG. As described above, each of first and second support portions 118 and 119 is provided by a part of substrate 121 made of, for example, Si provided with through-hole 120.

[0106] Such a displacement element 111 is provided between the first fulcrum 122 of the beam 112 and the second fulcrum 123 of the second support 119 by the electrostatic drive. The bending of the radius portion 124 is performed, whereby the beam 112 is displaced in the thickness direction. At a central portion 125 in the longitudinal direction of the effective radius portion 124, a thickness-providing member 126, for example, S, for increasing the thickness of the central portion 125 to be greater than other portions is disposed.

[0107] The effective radius portion 124 has a symmetric structure with respect to a perpendicular bisector 127 of the first fulcrum 122 and the second fulcrum 123! / Puru.

[0108] Also, in the effective radius portion 124, a first one-side radius between the first fulcrum 122 and the first inner end 128 located at the end of the thickness imparting member 126 on the first fulcrum 122 side. The portion 129 has a symmetrical structure with respect to a perpendicular bisector 130 between the first fulcrum 122 and the first inner end 128.

On the other hand, in the effective radius portion 124, a second one-side radius between the second fulcrum 123 and the second inner end 131 located at the end of the thickness imparting member 126 on the second fulcrum 123 side. The portion 132 also has a symmetric structure with respect to the perpendicular bisector 133 between the second fulcrum 123 and the second inner end 131.

[0110] Further, as is well shown in FIG. 11 (a), the effective radius portion 124 is formed by a first free end 134 and a second free end 135, which are ends in the width direction. It also has a symmetrical structure with respect to the perpendicular bisector 136 (corresponding to the cutting plane BB).

[0111] Although not shown, the thickness imparting member 126 extends over the entire area between the first free end 134 and the second free end 135, which are each end in the width direction of the effective radius portion 124. It is located at

[0112] Above the central portion 125 of the effective radius portion 124 of the beam 112, for example, a fixing member 137 that also has a glass force is fixedly disposed. A fixed conductor 139 is formed on the fixing member 137 with, for example, A1 so as to be positioned with the air layer 138 separated from the conductor layer 114 described above. The fixed conductor 139 is electrically connected to the extraction electrode 140 formed on the substrate 121. [0113] Next, an example of a method for manufacturing the displacement element 111 will be described.

[0114] First, a substrate 121, which is also made of S, is prepared. At this stage, the through hole 120 is not formed in the substrate 121.

Next, an SiO film serving as the insulator layer 113 is formed on the substrate 121 by thermal oxidation or sputtering.

2

Then, an insulator layer 113 is formed by wet etching. Next, an A1 film serving as the conductor layer 114 and the extraction electrode 115 is formed by a method such as lift-off. Further, a Cu film serving as the extraction electrode 140 is formed by a method such as lift-off. Here, the thickness of the extraction electrode 140 is larger than the thickness of the extraction electrode 115.

Next, a through-hole 120 is formed on the substrate 121 from the back side by applying a method such as RIE through a resist mask. At this time, the thickness providing member 126 is provided by a part of the substrate 121.

On the other hand, a fixed conductor 139 made of A1 is formed on the fixing member 137. Then, thermocompression bonding is performed so that the fixed conductor 139 and the extraction electrode 140 on the substrate 120 are joined.

[0118] As described above, the displacement element 111 can be obtained.

Next, an operation of the displacement element 111 will be described.

First, the displacement element 111 also has a symmetrical structure with respect to the effective radius portion 124 of the beam 112 and the first and second one-side radius portions 129 and 132. The absolute position in the state can always be controlled to be constant.

[0121] In this state, when a voltage is applied between the extraction electrodes 115 and 140, an electrostatic attraction acts between the conductor layer 114 and the fixed conductor 139, and the central portion 125 of the effective radius portion 124 becomes Displace upward. The amount of displacement can be controlled by the level of the voltage applied between the extraction electrodes 115 and 140.

[0122] As described above, according to the displacement element 111, the absolute position of the central portion 125 of the effective radius portion 124 of the beam 112 in the initial state can be controlled, so that the conductor layer 114 and the fixed conductor 139 By applying a voltage between them, an electrostatic attraction is generated between the conductor layer 114 and the fixed conductor 139, whereby the effective radius portion 124 can be radiused by a predetermined amount. Thus, it is possible to realize an electrostatically driven displacement element having good absolute position controllability. FIGS. 12 to 14 illustrate a variable capacitance element as a preferred application example of the displacement element according to the present invention. Here, FIG. 12 is a plan view of the displacement element 141, FIG. 13 is an end view of a cut section along the cut plane X--X of FIG. 12, and FIG. 14 is a cut section along the cut plane YY of FIG. It is a partial end view.

The displacement element 141 constituting the variable capacitance element includes a first substrate 142 made of, for example, Si and a second substrate 143 made of, for example, glass. In addition, the displacement element 141 includes first and second beams 144 and 145 on the first substrate 142 side. Since the first and second beams 144 and 145 have substantially the same configuration as each other, the first beam 144 will be mainly described below.

[0125] The beam 144 is formed of, for example, a buffer layer 146 that also has Al O force, for example, a lower electrode layer made of Pt.

twenty three

147, for example, a structure in which a piezoelectric layer 148 that also produces a PZT force and an upper electrode layer 149 that also produces an A1 force are laminated in the thickness direction. The upper electrode layer 149 is formed by being divided into first, second and third upper electrode layers 149a, 149b and 149c.

[0126] Also, first and second ends 150 and 151 in the longitudinal direction of beam 144 are supported by first and second support portions 152 and 153, respectively, so that beam 144 is held in both ends. Have been. As best shown in FIG. 12, each of the first and second support portions 152 and 153 is provided by a portion separated by providing a through hole 154 in the first substrate 142. .

[0127] The piezoelectric layer 148 provided on the beam 144 is distorted based on the piezoelectric effect, so that the first fulcrum 155 of the first support 152 and the second support 153 of the second support 153 on the beam 144 are provided. The effective radius 157 between the fulcrum 156 and the fulcrum 156 is deflected, so that the beam 144 is displaced in the thickness direction. At a central portion 158 in the longitudinal direction of the effective radius portion 157, a thickness imparting member 159, for example, S, for increasing the thickness of the central portion 158 more than other portions is disposed.

In this embodiment, the thickness imparting member 159 is disposed so as to extend to the central portion 161 of the effective radius portion 160 of the second beam 145, and both the first and second beams 144 and 145 are provided. Fixed to.

[0129] The effective radius portion 157 is a vertical bisecting surface 162 of the first fulcrum 155 and the second fulcrum 156 (cut (Corresponding to the cross section Y-Y).

[0130] Further, in the effective radius portion 157, a first one-side radius between the first fulcrum 155 and the first inner end 163 located on the first fulcrum 155 side end of the thickness imparting member 159. The only portion 164 has a symmetrical structure with respect to a perpendicular bisector 165 between the first fulcrum 155 and the first inner end 163.

On the other hand, in the effective radius portion 157, a second one-side radius between the second fulcrum 156 and the second inner end 166 located at the end of the thickness imparting member 159 on the second fulcrum 156 side. The portion 167 also has a symmetric structure with respect to a perpendicular bisector 168 between the second fulcrum 156 and the second inner end 166.

[0132] Further, as is well shown in Fig. 12, the effective radius portion 157 is formed by a vertical free end of a first free end 169 and a second free end 170, which are ends in the width direction. It also has a symmetric structure with respect to the dividing plane 171 (corresponding to the cutting plane X—X).

Further, an extraction electrode 172 is electrically connected to a lower electrode layer 147 provided on the beam 144 and a lower electrode layer (not shown) provided on the other beam 145, and an end of the extraction electrode 172 is connected to the terminal shown in FIG. As shown in FIG. 8, the first substrate 142 is formed so as to be exposed to the outside.

In the upper electrode layer 149 provided on the beam 144, the first and second upper electrode layers 149 a and 149 b located at both ends and the corresponding upper electrode layer provided on the other beam 145 include Electrode 173 is electrically connected.

On the other hand, on the second substrate 143, for example, electrodes 174 and 175 that also generate A1 force are formed in a state where they are aligned with each other. Further, the first substrate 142 and the second substrate 143 are joined to each other via a gap adjusting member 176. In this joined state, an electrode 178 having, for example, an A1 force is formed at a position separated by the air layer 177 so as to form a capacitance with respect to the electrodes 174 and 175, that is, on the lower surface of the thickness applying member 159. You.

Next, an example of a method for manufacturing the displacement element 141 will be described.

[0137] First, a first substrate 142 that also contains S is prepared. At this stage, the through holes 154 are formed in the first substrate 142.

Next, an Al 2 O 3 film serving as the buffer layer 146 is formed on the first substrate 142 by sputtering or

twenty three

It is formed on the entire surface by a method such as vapor deposition. Next, a Pt film to be the lower electrode layer 147 is sputtered. It is formed on the entire surface by a method such as tarling or vapor deposition.

[0139] Next, a PZT film to be the piezoelectric layer 148 is formed on the entire surface by a method such as MOCVD or sputtering.

Next, an A1 film serving as the upper electrode layer 149 and the extraction electrode 173 is formed by a method such as lift-off.

twenty three

By applying a method such as on-milling, processing is performed so that the corresponding elements in the piezoelectric layer 148, the lower electrode layer 147, the buffer layer 146, and the second beam 145 in the first beam 144 are obtained. Next, through a resist mask, the piezoelectric layer 148 in the first beam 144 and the corresponding element in the second beam 145 are processed by a method such as ion milling, so that the extraction electrode 172 is formed. Expose part of the

Next, a through-hole 154 is formed on the first substrate 142 from the back side thereof by a method such as RIE through a resist mask. At this time, the thickness applying member 159 is provided by a part of the first substrate 142.

On the other hand, electrodes 174 and 175 are formed on second substrate 143 by a method such as lift-off. Then, a gap adjusting member 176 is formed on the second substrate 143 using, for example, a photosensitive polyimide or the like, and then the first substrate 142 is thermocompression-bonded thereto.

[0144] As described above, the displacement element 141 can be obtained.

[0145] Next, the operation of the displacement element 141 will be described.

First, as described above, since each of the first and second beams 144 and 145 has a symmetric structure, the center portions 158 and 161 of the effective radius portions 157 and 160 are respectively formed. The absolute position in the initial state can always be controlled to be constant.

In this initial state, the capacitance formed by the electrodes 174 and 175 and the electrode 178 can be taken out through the electrodes 174 and 175.

[0148] Next, when a voltage is applied between the extraction electrode 172 and the extraction electrode 173, the piezoelectric layer 148 is distorted, and the central portions 158 and 161 of the effective radius portions 157 and 160 are displaced upward or downward, As a result, the distance between the electrodes 174 and 175 and the electrode 178 is changed, and the capacitance is changed. The degree of change in the capacitance is applied between the extraction electrodes 172 and 173. It can be controlled by the height of the applied voltage.

As described above, according to the displacement element 141 constituting the variable capacitance element, the absolute positions in the initial state of the central portions 158 and 161 of the effective radius portions 157 and 160 of the beams 144 and 145 are fixed. Therefore, the amount of displacement generated when a voltage is applied can be controlled with high precision, and as a result, the capacitance can be controlled with high precision.

Industrial applicability

The displacement element according to the present invention can be applied as a variable capacitance element capable of controlling a capacitance value with high accuracy.

Claims

The scope of the claims

[1] a beam having a structure in which a plurality of functional material layers made of different materials are stacked in the thickness direction,

First and second support portions for supporting first and second longitudinal ends of the beam, respectively, so as to hold the beam in a double-supported state;

In order to cause the beam to be displaced in the thickness direction, an effective radius portion between the first fulcrum of the first support and the second fulcrum of the second support in the beam. Driving means for electrically driving so as to deflect

A displacement element comprising:

At the central portion in the longitudinal direction of the effective radius portion, a thickness imparting member for increasing the thickness of the central portion relative to other portions is arranged,

The effective radius portion has a symmetric structure with respect to a perpendicular bisector of the first fulcrum and the second fulcrum,

In the effective radius portion, a first unilateral radius portion between the first fulcrum and a first inner end located at an end of the thickness imparting member on the first fulcrum side is the first radius. 1 has a symmetric structure with respect to a perpendicular bisector of the fulcrum and the first inner end, and

In the effective radius portion, a second one-side radius portion between the second fulcrum and a second inner end located at the second fulcrum-side end of the thickness providing member is the second radius. A displacement element having a symmetrical structure with respect to a perpendicular bisector of the second fulcrum and the second inner end.

[2] The effective radius portion has a symmetrical structure with respect to a perpendicular bisector of a first free end and a second free end which are each end in the width direction. The displacement element according to claim 1, wherein

[3] The thickness providing member is arranged so as to extend over the entire area between the first free end and the second free end, which are each end in the width direction of the effective radius portion. The displacement element according to claim 1 or 2.

[4] At least one of the plurality of functional material layers is a piezoelectric layer having a piezoelectric force, and the driving means includes means for distorting the piezoelectric layer based on a piezoelectric effect. 4. The displacement element according to claim 1, wherein the displacement element is characterized by:

[5] At least one of the plurality of functional material layers is a conductor layer having a conductor force, and the driving unit is configured to generate a magnetic field line by passing a current through the conductor layer; Means for generating an electromagnetic force in the body layer to apply a magnetic field to the conductor layer from outside so as to cause the effective radius to be radiused, wherein , A displacement element according to any of the above.

[6] At least one of the plurality of functional material layers is a conductive layer having a conductive property, and the driving unit is fixedly provided at a position separated from the conductive layer by an air layer. Fixed electric conductor, and means for applying a voltage between the electric conductor layer and the fixed electric conductor, and applying a voltage between the electric conductor layer and the fixed electric conductor, The displacement element according to any one of claims 1 to 3, wherein an electrostatic attraction is generated between an electric conductor layer and the fixed conductor, whereby the effective radius portion is radiused.

[7] A first electrode provided on the effective radius portion including the thickness imparting member, and a first electrode fixed to a position separated by an air layer so as to form a capacitance with respect to the first electrode. And a second electrode provided in the variable capacitance element, wherein the capacitance is changed by the radius of the effective radius portion. The displacement element according to any one of the above.