Vibration type actuator, optical apparatus, and electronic apparatus

Abstract

To provide a vibration type actuator in which generation of noise in driving is reduced.SOLUTION: A vibration type actuator comprises a vibration body including an elastic body and an electric-mechanical energy conversion element and a contact body which is pressed and in contact with the vibration body, and the vibration body and the contact body are relatively moved by vibration of the vibration body. An intermediate member is included between the elastic body and the electric-mechanical energy conversion element and the intermediate member includes at least one of a through hole, a groove and a slit.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a vibration type actuator, an optical device, and an electronic device.

Background Art

[0002] Generally, a vibration type actuator obtains a driving force by bringing a vibrating body and a driven body (contact body) into pressure contact and relatively frictionally driving the vibrating body and the driven body by vibration excited in the vibrating body. Therefore, the vibration type actuator has a simple structure, is thin, and can perform highly accurate and quiet driving. The vibration type actuator has been applied as a drive motor for a lens barrel in which a lens is movable, a swing drive device such as a pan-tilt head, a production device such as FA (Factory Automation), and OA equipment.

[0003] For example, Patent Document 1 describes a technique for reducing the number of parts and miniaturizing a vibration type actuator, and suppressing the generation of abnormal noise. Specifically, the vibration type actuator described in Patent Document 1 has a structure in which a holding member that holds a vibrating body holds the posture of the vibrating body by contacting and pressing a position near a node of the vibration generated in the vibrating body.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the vibration type actuator disclosed in Patent Document 1, when the frequency of an alternating voltage is swept from a frequency higher than the resonance frequency of the vibration mode used for driving so as to approach the resonance frequency, abnormal noise called "whining" may occur in a specific frequency region.

[0006] Specifically, in the frequency range through which the fourth harmonic component excited during the sweep of the AC voltage frequency passes, unwanted vibrations different from the vibrations used for driving occur as self-excited vibrations. When these unwanted vibrations occur, the contact between the vibrating body and the driven body becomes unstable, and fractional harmonic vibrations of 1 / 2 of the AC voltage frequency and various unwanted vibrations occur. And since the difference between the frequencies of these unwanted vibrations and the original vibration becomes an audible vibration, it causes abnormal noise, and also the driving of the vibration type actuator becomes unstable.

[0007] Therefore, an object of the present invention is to provide a vibration type actuator in which generation of abnormal noise during driving is reduced. Another object of the present invention is to provide an optical device or an electronic device including a vibration type actuator in which generation of abnormal noise during driving is reduced.

Means for Solving the Problems

[0008] The above object is achieved by the following present invention. That is, according to the present invention, there is provided a vibration type actuator including a vibrating body having an elastic body and an electro-mechanical energy conversion element, and a contact body that is pressed and contacts the vibrating body, and the vibration of the vibrating body relatively moves the vibrating body and the contact body, and an intermediate member is provided between the elastic body and the electro-mechanical energy conversion element, and the intermediate member has at least one of a through hole, a groove, or a slit.

[0009] Also, according to the present invention, there is provided an optical device or an electronic device including a vibration type actuator including a vibrating body having an elastic body and an electro-mechanical energy conversion element, and a contact body that is pressed and contacts the vibrating body, and the vibration of the vibrating body relatively moves the vibrating body and the contact body, and an intermediate member is provided between the elastic body and the electro-mechanical energy conversion element, and the intermediate member has at least one of a through hole, a groove, or a slit.

Effects of the Invention

[0010] According to the present invention, it is possible to provide a vibration type actuator in which the generation of abnormal noise during driving is reduced. Further, according to the present invention, it is possible to provide an optical device or an electronic device including a vibration type actuator in which the generation of abnormal noise during driving is reduced.

Brief Description of the Drawings

[0011]

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Modes for Carrying Out the Invention

[0012] The present inventors have studied a method for reducing the generation of abnormal noise called "whining" of a vibration type actuator. As a result, when abnormal noise is generated, it has been found that unnecessary vibrations different from the driving vibration may occur as self-excited vibrations in the frequency region through which the fourth harmonic component excited during the sweeping of the frequency of the alternating voltage passes. It is presumed that the contact between the vibrating body and the driven body becomes unstable due to the occurrence of this unnecessary vibration, and abnormal noise in the audible range is generated due to the occurrence of the 1 / 2 fractional harmonic vibration of the frequency of the alternating voltage and various unnecessary vibrations.

[0013] As a result of further study, the present inventors have found that a design in which the region of the fourth harmonic component of the vibration mode used for driving does not overlap with the resonance frequency of the vibration mode of a specific unnecessary vibration (mode C) is effective in reducing the generation of abnormal noise. That is, the present inventors have found that performing a design to lower the resonance frequency of the vibration mode of a specific unnecessary vibration is effective in reducing the generation of abnormal noise.

[0014] Specifically, by providing an intermediate member between the elastic body and the piezoelectric element (electromechanical energy conversion element), and by having the intermediate member have at least one of a through hole, a groove, or a slit, the resonance frequency of the vibration mode of a specific unwanted vibration can be reduced. It is presumed that this is because by having the intermediate member have at least one of a through hole, a groove, or a slit, the rigidity of the portion corresponding to the nodal part of the unwanted vibration in the vibrating body can be selectively reduced.

[0015] Hereinafter, preferred embodiments will be given to explain the present invention in more detail.

[0016] The vibration type actuator in this embodiment includes a vibrating body having an elastic body and an electromechanical energy conversion element, and a contact body that is pressurized and contacts the vibrating body. The vibration type actuator in this embodiment has an intermediate member between the elastic body and the piezoelectric element (electromechanical energy conversion element), and the intermediate member has at least one of a through hole, a groove, or a slit. With this configuration, by making the resonance frequency of a specific unwanted vibration (mode C) lower than the region of the harmonic component four times the driving frequency and outside the range of the region, the generation of abnormal noise and the degradation of performance are reduced.

[0017] Here, it is preferable that the elastic body and the intermediate member have a rectangular and flat plate shape. By having the elastic body and the intermediate member have a rectangular and flat plate shape, a thin vibrating body can be obtained.

[0018] The elastic body has a contact portion that contacts the contact body. In the pressurizing direction (the direction in which the vibrating body is pressurized against the contact body), it is preferable that the intermediate member is adhered to the surface opposite to the surface having the contact portion of the elastic body. In the pressurizing direction, it is preferable that the piezoelectric element (electromechanical energy conversion element) is adhered to the surface opposite to the surface of the intermediate member that is adhered to the elastic body.

[0019] As an example, the through hole provided in the intermediate member is preferably a through hole that penetrates from the bonding surface of the intermediate member with the elastic body to the bonding surface with the electro-mechanical energy conversion element. As another example, it is preferable that the groove of the intermediate member has an opening on the bonding surface of the intermediate member with the elastic body, and the bonding surface of the intermediate member with the electro-mechanical energy conversion element has a uniform planar shape.

[0020] Further, as a modified example of the intermediate member, the intermediate member is composed of a plurality of flat plates, and the plurality of flat plates are bonded to the elastic body and the electro-mechanical energy conversion element with a gap between each of them, so that slits of the intermediate member may be formed. The intermediate member has a plurality of through holes, and the plurality of through holes may be provided side by side along the direction of relative movement between the vibrating body and the contacting body.

[0021] More preferably, the following forms can be cited as the form of the intermediate member.

[0022] The through hole, groove, or slit of the intermediate member is preferably provided at a symmetric position with respect to the axis in the direction of relative movement between the vibrating body and the contacting body passing through the center of the intermediate member, and the axis in the direction orthogonal to the direction of relative movement and the pressing direction.

[0023] The through hole, groove, or slit of the intermediate member is preferably provided near a node of vibrations different from the vibrations used for driving the vibration type actuator. The through hole, groove, or slit of the intermediate member preferably has a long hole shape extending in the direction of relative movement between the vibrating body and the contacting body.

[0024] Other embodiments include an optical device including a vibration type actuator having the above-described configuration and at least one of an optical element or an imaging element driven by the vibration type actuator. Further, other embodiments include an electronic device including a vibration type actuator having the above-described configuration and a member driven by the vibration type actuator.

[0025] [Examples] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples as long as it does not exceed the gist thereof. The embodiments of the present invention will be described by the following examples.

[0026] The mode for carrying out the present invention will be described by the following examples.

[0027] <Example 1> FIG. 1 is a perspective view showing a schematic configuration of a vibration type actuator 100 according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view of the vibration type actuator 100. Here, the moving direction of the contact member 9 (the direction of relative movement between the vibrating body 2 and the contact member 9) is defined as the X direction, the pressing direction is defined as the Z direction, and the direction perpendicular to the X direction and the Z direction is defined as the Y direction. The pressing direction is the direction in which the vibrating body 2 presses against the contact member 9.

[0028] The vibrating body 2 has an elastic body 3 and two protrusions 31 which are an example of a contact portion provided on one surface of the elastic body 3. The vibrating body 2 further has an intermediate member 33 provided on the surface of the elastic body 3 opposite to the surface on which the protrusions 31 are provided, and a piezoelectric element 4 provided on the surface of the intermediate member 33 opposite to the elastic body 3. Further, it has a flexible printed circuit board 5 fixed to the piezoelectric element 4 on the surface opposite to the elastic body 3. Note that at least one protrusion 31 enables driving of the contact member 10.

[0029] The elastic body 3 having a substantially rectangular and flat plate shape is a metallic elastic member. The elastic body 3 contains, for example, martensitic stainless steel or the like as a material. Further, the elastic body 3 is subjected to a hardening treatment such as quenching as a hardening treatment for enhancing durability. The protrusions 31 are formed with a thickness having spring properties. The protrusions 31 are integrally formed with the elastic body 3, for example, by press working a plate material constituting the elastic body 3. However, the present invention is not limited thereto, and the protrusions 31 may be fixed to the elastic body 3 by welding or the like. The tip (upper surface) of the protrusion 31 is subjected to a hardening treatment such as quenching in order to enhance wear resistance because it frictionally slides with the contact member 9.

[0030] The intermediate member 33 provided between the elastic body 3 and the piezoelectric element 4 is adhered to the elastic body 3 by an adhesive. That is, the intermediate member 33 is adhered to the surface of the elastic body 3 on the side opposite to the surface where the protrusion 31 (contact portion) of the elastic body 3 is located in the pressing direction. The intermediate member 33 is an elastic member made of metal like the elastic body 3, and for example, martensitic stainless steel or the like is used as the material. The shape of the intermediate member 33 will be described later.

[0031] The piezoelectric element 4, which is an electro-mechanical energy conversion element that converts an electrical quantity into a mechanical quantity, is adhered to the intermediate member 33 by an adhesive. That is, the piezoelectric element 4 is adhered to the surface of the intermediate member 33 on the side opposite to the adhesive surface with the elastic body 3 in the pressing direction. The piezoelectric element 4 has a structure in which electrodes of a predetermined shape are formed on both surfaces of a plate-shaped piezoelectric ceramic.

[0032] The vibration type actuator 100 is driven by applying a driving voltage (alternating voltage) of a predetermined frequency from the flexible printed circuit board 5 to the electrodes of the piezoelectric element 4.

[0033] A holding member 6 for pressing and supporting the vibrating body 2 is provided below the vibrating body 2. The holding member 6 is applied with a pressing force in the Z direction by a pressing spring 7, and the reaction force is received by the base 8 which is a pressure receiving member. The pressing spring 7 employs a conical coil spring in order to miniaturize the vibration type actuator 100 in the Z direction. Note that the coil shape is shown in a simplified manner. In this embodiment, a pressing force of 600 gf is applied by the pressing spring 7.

[0034] A contact body 9 is provided above the vibrating body 2 (in the Z direction in FIG. 2) and is in pressure contact with the protrusion 31 of the elastic body 3. The contact body 9 is fixed to the contact body holder 10 and is integrally driven in the X direction. Note that rubber for vibration damping may be provided between the contact body 9 and the contact body holder 10. The contact body 9 is made of a highly wear-resistant metal, ceramic, resin, or a composite material thereof. The contact body 9 is preferably formed of a material obtained by nitriding stainless steel such as SUS420J2 from the viewpoints of wear resistance and mass productivity.

[0035] Three pairs of upper and lower rails provided on the contact body holder 10 and the ball rail 12 sandwich three balls 11, and by fixing the ball rail 12 to the base 8, the contact body 9 and the contact body holder 10 can move in the X direction with respect to other components. By attaching an output transmission part with a desired shape to the contact body holder 10, the output is transmitted to the outside. In this embodiment, an example is shown in which the vibrating body 2 is fixed and the contact body 9 moves, but conversely, it is also possible to fix the contact body 9 and move the vibrating body 2.

[0036] Next, with reference to FIG. 3, the vibration modes excited in the vibrating body 2 will be described. In this embodiment, an AC voltage is applied to the piezoelectric element 4 through the flexible printed circuit board 5 to excite two different out-of-plane bending vibrations in the vibrating body 2, and a vibration obtained by synthesizing these vibrations is generated. Note that FIG. 3 shows a shape in which the displacement amount is enlarged compared to the actual shape of the vibrating body 2 in order to facilitate understanding of the deformed shape.

[0037] Mode A, which is the first vibration mode, is a primary out-of-plane bending vibration mode in which two nodes appear parallel to the X direction, which is the longitudinal direction of the vibrating body 2. Due to the vibration of mode A, the two protrusions 31-1 and 31-2 are displaced in the Z direction, which is the pressing direction. Mode B, which is the second vibration mode, is a secondary out-of-plane bending vibration mode in which approximately three nodes appear in the Y direction, which is the short side direction of the vibrating body 2. Due to the vibration of mode B, the two protrusions 31-1 and 31-2 are displaced in the X direction.

[0038] By synthesizing the vibrations of these modes A and B, the two protrusions 31-1 and 31-2 perform elliptical or circular motion in the ZX plane. By pressing the contact body 9 against these protrusions 31-1 and 31-2, a frictional force is generated in the X direction, and a driving force (thrust force) for relatively moving the vibrating body 2 and the contact body 9 is generated. In this embodiment, since the vibrating body 2 is held by the holding member 6, the contact body 9 moves in the X direction. Note that the position of the contact body can also be fixed with a fixing member or the like so that the vibrating body 2 moves in the X direction.

[0039] In order to efficiently drive the vibration type actuator 100, it is necessary to support the vibrating body 2 without inhibiting the vibration (displacement) of the two vibration modes that excite the vibrating body 2. For this purpose, it is desirable to support the vicinity of the nodes of these two vibration modes. For such reasons, in order to pressurize and hold the common node of the two vibration modes excited in the vibrating body 2, as shown in FIG. 2, convex portions 61-1 and 61-2 serving as two abutting portions are provided on the holding member 6.

[0040] FIG. 4 shows an exploded perspective view of the vibrating body 2. As shown in FIG. 4, the intermediate member 33 has four long holes 33-1A, 33-1B, 33-2A, and 33-2B that extend in the X direction (the direction of relative movement between the vibrating body 2 and the contact body 9), which is an example of a through hole. Note that the four long holes are provided as through holes that penetrate the intermediate member 33 in the Z direction. That is, the four long holes penetrate from the bonding surface of the intermediate member 33 with the elastic body 3 to the bonding surface of the intermediate member 33 with the piezoelectric element 4. By fixing the elastic body 3, the intermediate member 33, and the piezoelectric element 4 with an adhesive respectively, the vibrating body 2 is formed.

[0041] The intermediate member 33 is made of a material such as martensitic stainless steel, and the four long holes 33-1A, 33-1B, 33-2A, and 33-2B are formed by punching with a press. However, any processing method may be used as long as a rectangular outer shape and a through-shaped long hole shape can be formed, such as cutting, electrical discharge machining, or etching.

[0042] In this embodiment, the elastic body 3 has a thickness of 0.35 mm, the intermediate member 33 has a thickness of 0.1 mm, and the piezoelectric element 4 has a thickness of 0.3 mm, and the frequency of mode B in FIG. 3 is 100 kHz. In this case, the frequency of the alternating voltage (hereinafter also referred to as the "driving frequency") for driving the vibration type actuator 100 will sweep from 107 kHz to 100 kHz.

[0043] FIG. 5 is a schematic diagram showing a drive frequency region and frequency regions of its harmonic components. The frequency region f1 indicates a range of drive frequencies from 107 kHz to 100 kHz. Also, f2, f3, and f4 respectively indicate regions of harmonic components that are 2 times, 3 times, and 4 times the drive frequency region. The range expands as the order increases. The frequency fc is the resonance frequency of the vibration mode (hereinafter referred to as "mode C") shown in FIG. 6.

[0044] FIG. 6 is a perspective view showing the deformation of the vibrating body 2 in mode C having the frequency fc as the resonance frequency. Note that, similar to FIG. 3, FIG. 6 shows an enlarged displacement amount compared to the shape of the vibrating body 2 for easy understanding of the deformed shape.

[0045] Mode C is one of the natural vibration modes that can be excited by applying a voltage to the vibrating body 2. The vibration of mode C is a third-order bending vibration in the Y direction of the vibrating body 2 and a fifth-order bending vibration in the X direction.

[0046] Mode C is one of the unnecessary vibrations that are not required for driving the vibration type actuator 100. In other words, mode C is one of the vibration modes different from the vibration used for driving the vibration type actuator 100. Also, mode C has a resonance frequency higher than the region of the third harmonic component of the drive frequency region of the vibration type actuator 100 and close to the region of the fourth harmonic component.

[0047] In this embodiment, the resonance frequency of mode C is 378 kHz, which is lower than the region of 428 kHz to 400 kHz, which is the region of the fourth harmonic component.

[0048] Therefore, even when the vibration type actuator 100 is driven at a predetermined drive frequency range of 107 kHz to 100 kHz, the region of its fourth harmonic component does not pass through the resonance frequency of mode C.

[0049] Therefore, it is possible to suppress the generation of the vibration in Mode C, which is unnecessary vibration when the vibration type actuator 100 is driven. Therefore, it is possible to reduce the generation of abnormal noise and stably drive the vibration type actuator 100.

[0050] Here, the effect of providing the intermediate member 33 between the elastic body 3 and the piezoelectric element 4 will be described using a comparative example.

[0051] FIG. 7 shows a vibration type actuator having a conventional structure which is Comparative Example 1, and FIG. 7(a) shows an exploded perspective view of the vibrating body 102 of Comparative Example 1. Further, FIG. 7(b) is a schematic diagram showing the driving frequency region of Comparative Example 1 and the frequency regions of its harmonic components.

[0052] As shown in FIG. 7(a), the vibrating body 102 of Comparative Example 1 has a structure in which no intermediate member is provided between the elastic body 103 and the piezoelectric element 104, and the elastic body 103 and the piezoelectric element 104 are fixed by an adhesive. Similar to Example 1, the elastic body 103 has a thickness of 0.35 mm and the piezoelectric element 104 has a thickness of 0.3 mm.

[0053] As shown by f1 in FIG. 7(b), the range of the driving frequency is 95 to 88 kHz, and the resonance frequency is lowered by the amount that the intermediate member 33 is absent. In Comparative Example 1, the resonance frequency fc of Mode C is 373 kHz, and it is within the range of 380 kHz to 352 kHz which is the region of the fourth harmonic component as shown in FIG. 7(b).

[0054] Therefore, as described above, before and after the fourth harmonic component passes through the resonance frequency of Mode C when the vibration type actuator is driven, the vibration of Mode C occurs as self-excited vibration, and the contact between the vibrating body and the driven body becomes unstable. As a result, subharmonic vibrations of 1 / 2 of the driving frequency and various unnecessary vibrations are generated, and the frequency differences of these vibrations become frequencies in the audible range, which causes abnormal noise generation and the driving of the vibration type actuator also becomes unstable.

[0055] In this embodiment, by providing the intermediate member 33 between the elastic body 3 and the piezoelectric element 4, the resonance frequency of the vibration in mode C is made lower than the region of the harmonic component four times the driving frequency and outside the region, thereby reducing the generation of abnormal noise and the degradation of performance.

[0056] Next, the effect of providing four long holes 33-1A, 33-1B, 33-2A, and 33-2B in the intermediate member 33 will be described using a comparative example in which no holes are provided.

[0057] FIG. 8 shows a vibration type actuator which is Comparative Example 2, and FIG. 8(a) shows an exploded perspective view of the vibrating body 202 of Comparative Example 2. Further, FIG. 8(b) is a schematic diagram showing the driving frequency region and the frequency region of its harmonic components of Comparative Example 2.

[0058] As shown in FIG. 8(a), the vibrating body 202 of Comparative Example 2 has an intermediate member 233 without through holes such as long holes between the elastic body 203 and the piezoelectric element 204, and the elastic body 203, the intermediate member 233, and the piezoelectric element 204 are fixed by an adhesive. Similar to Embodiment 1, the elastic body 3 has a thickness of 0.35 mm, the intermediate member 33 has a thickness of 0.1 mm, and the piezoelectric element 4 has a thickness of 0.3 mm.

[0059] As shown by f1 in FIG. 8(b), the driving frequency range is 107.3 kHz to 100.3 kHz, which is slightly higher (300 Hz) by the amount without holes compared to Embodiment 1. On the other hand, the resonance frequency fc of mode C is 417 kHz, and it is within the range of 429.2 kHz to 401.2 kHz which is the region of the harmonic component four times as shown in FIG. 8(b).

[0060] Therefore, also in Comparative Example 2, the vibration in mode C occurs as self-excited vibration during the driving of the vibration type actuator, resulting in the generation of abnormal noise and unstable performance.

[0061] In this embodiment, by providing four long holes 33-1A, 33-1B, 33-2A, and 33-2B in the intermediate member 33, the resonance frequencies of the two vibrations used for driving can be kept from changing much, and only the frequency of the vibration of mode C, which is unnecessary vibration, can be greatly reduced.

[0062] Here, the positions of the long holes in the intermediate member 33 of this embodiment will be described with reference to FIG. 9.

[0063] FIG. 9(a) shows a plan view of the intermediate member 33 as viewed from the piezoelectric element 4 side, and FIG. 9(b) shows the nodal positions of the elastic body 3 during the vibration of mode C.

[0064] From FIGS. 9(a) and (b), the four long holes 33-1A, 33-1B, 33-2A, and 33-2B in the intermediate member 33 are provided symmetrically with respect to the L1 axis and the L2 axis, which are axes parallel to the X axis and the Y axis passing through the center of the intermediate member 33, respectively. Therefore, the vibration shapes of modes A and B, which are the vibrations used for driving, are not made asymmetric, and stable driving vibration can be maintained. Also, the positions of the four long holes 33-1A, 33-1B, 33-2A, and 33-2B in the Y direction are provided near the positions of the nodes of mode C shown by the black lines in FIG. 9(b).

[0065] For this reason, the rigidity near the nodes of mode C can be selectively reduced, the change in the resonance frequencies of modes A and B, which are the driving vibrations, can be suppressed, and the resonance frequency of mode C can be greatly reduced.

[0066] Of the four long holes, the widths in the Y direction of the two long holes 33-2A and 33-2B near the center in the Y direction are larger than the widths in the Y direction of the two long holes 33-1A and 33-1B on both end sides. This is because the vicinity of the center of the long holes is enlarged in accordance with the distribution of the nodes of the vibration of mode C shown by the black line in Fig. 9(b). Also, the widths in the X direction of the two long holes 33-2A and 33-2B near the center are smaller than the widths in the Y direction of the two long holes 33-1A and 33-1B on both end sides. This is because the openings of the protrusions 31 of the elastic body 3 are located near the X-direction ends of the two long holes 33-2A and 33-2B near the center in the Y direction, and they are made shorter from the viewpoint of the adhesion strength.

[0067] Comparing this example with Comparative Example 2, in Comparative Example 2 without through holes, the resonance frequency of mode B was 100.3 kHz and the resonance frequency of mode C was 417 kHz. On the other hand, for this example with through holes, the frequency of mode B was 100 kHz and the resonance frequency of mode C was 378 kHz. Therefore, by providing through holes near the nodes of mode C, the change in the frequency of mode B, which is the mode used for driving, can be suppressed to 300 Hz, and the frequency of mode C, which is unnecessary vibration, can be significantly reduced to 39 kHz.

[0068] From the above, the resonance frequency of the unnecessary vibration in the region of the fourth harmonic component of the driving frequency, which was a problem in the vibrating body of the conventional structure, can be changed outside the range of the region of the fourth harmonic component by using the intermediate member 33. Thereby, the generation of abnormal noise in the vibration type actuator 100 can be reduced, and stable driving can be realized.

[0069] Note that the shape of the through holes of the intermediate member 33 in this example is not limited to the above shape that forms four long holes.

[0070] For example, as shown in Modification 1 of FIG. 10(a), a plurality of round holes may be provided in the intermediate member 333 so as to penetrate in the X direction. By making the holes round, it becomes possible to perform press working inexpensively and easily. In relation to the node position of Mode C, the diameter of the holes 333-2A and 333-2B on the central part side is larger than the diameter of the holes 333-1A and 333-1B on both end part sides in the Y direction.

[0071] Further, as shown in Modification 2 of FIG. 10(b), four slits (gaps) 433-1A, 433-1B, 433-2A, and 433-2B may be provided. That is, a plurality of small rectangular flat plates 433-3 having different shapes may be arranged side by side so as to have gaps therebetween, thereby forming an intermediate member 433 having slits. By fixing the elastic body and the piezoelectric element with an adhesive in a state where the plurality of flat plates 433-3 have gaps between them, it is possible to manufacture without performing drilling. Note that the plurality of flat plates 433-3 are represented by diagonal hatching in the figure.

[0072] Also in the above two modifications, since through holes are provided in the intermediate members 333 and 433 near the node position of the vibration mode of Mode C, the resonance frequency of Mode C can be lowered outside the range of the fourth harmonic component region of the driving frequency. Therefore, the generation of abnormal noise in the vibration type actuator can be suppressed and stable driving can be realized.

[0073] Further, in the present embodiment, the resonance frequency is changed by the intermediate member for Mode C in the vicinity of the region of the fourth harmonic component, but it is not limited thereto. For unnecessary vibrations in any frequency regions such as driving, second harmonic, and third harmonic, by providing the through hole of the intermediate member near the node of the unnecessary vibration, the frequency of the target unnecessary vibration can be selectively changed.

[0074] Also, in the present embodiment, the thickness and the resonance frequency are exemplified by specific numerical values, but it is not limited thereto, and a vibration type actuator having an arbitrary thickness and frequency may be used.

[0075] <Example 2> As Example 2, a configuration example of a vibration type actuator in a form different from that of Example 1 will be described with reference to FIG. 11. In this example, as compared with Example 1, it is different from the structure shown in FIG. 1 in that the intermediate member 533 has a configuration with grooves as shown in FIG. 11. Since other elements of this example are the same as the corresponding ones of Example 1 described above, the description will be omitted by aligning the last two digits of the figure numbers.

[0076] FIG. 11(a) shows an exploded perspective view of the vibrating body 502 of the vibration type actuator of this example. FIG. 11(b) is a plan view of the intermediate member 533 as viewed from the elastic body 503 side, and FIG. 11(c) is a plan view of the intermediate member 533 as viewed from the piezoelectric element 504 side. Further, FIG. 11(d) is a schematic diagram showing the driving frequency region and the frequency regions of its harmonic components.

[0077] As shown in FIGS. 11(a), (b), and (c), the intermediate member 533 provided between the elastic body 503 and the piezoelectric element 504 has four long grooves 533-1A, 533-1B, 533-2A, and 533-2B extending in the X direction. By fixing the elastic body 503, the intermediate member 533, and the piezoelectric element 504 with an adhesive respectively, the vibrating body 502 is formed.

[0078] The four long grooves 533-1A, 533-1B, 533-2A, and 533-2B are each open on the surface on the elastic body 503 side in the Z direction. On the contrary, the surface on the piezoelectric element 504 side has no holes or the like and has a uniform planar shape. Thereby, the adhesion between the intermediate member 533 and the piezoelectric element 504 becomes stronger, and peeling of the adhesion can be prevented.

[0079] The intermediate member 533 is made of a material such as martensitic stainless steel, and the four long grooves 533-1A, 533-1B, 533-2A, and 533-2B are formed by half etching of etching to a depth of about 50% of the plate thickness. That is, it has a thin-walled shape. Note that it may be formed by machining such as cutting.

[0080] Also in this embodiment, similarly to Embodiment 1, the elastic body 503 is formed with a thickness of 0.35 mm, the intermediate member 533 is formed with a thickness of 0.1 mm, and the piezoelectric element 504 is formed with a thickness of 0.3 mm.

[0081] Further, the four long grooves 533-1A, 533-1B, 533-2A, and 533-2B of the intermediate member 533 are symmetrically provided with respect to the L1 axis and the L2 axis, which are axes parallel to the X axis and the Y axis passing through the center of the intermediate member 533, respectively. And the Y-direction positions of the four long grooves 533-1A, 533-1B, 533-2A, and 533-2B are provided near the position of the node of Mode C shown by the black line in FIG. 9(b). For this reason, the rigidity near the node of Mode C can be selectively reduced, the change in the resonance frequencies of Mode A and Mode B, which are driving vibrations, can be suppressed, and the resonance frequency of Mode C can be significantly lowered.

[0082] As shown by f1 in FIG. 11(d), the driving frequency range is 107 kHz to 100 kHz. The resonance frequency fc of Mode C, which is an unnecessary vibration, is 390 kHz, which is lower than the frequency range of 428 kHz to 400 kHz, which is the region of the fourth harmonic component. Therefore, even when the vibration type actuator 500 is driven in the predetermined driving frequency range of 107 kHz to 100 kHz, the region of the fourth harmonic component of the driving frequency does not pass through the resonance frequency of Mode C.

[0083] Thereby, the generation of the vibration of Mode C, which is an unnecessary vibration, during the driving of the vibration type actuator 500 can be reduced, the generation of abnormal noise can be reduced, and the vibration type actuator 500 can be stably driven.

[0084] <Embodiment 3> As Embodiment 3, a configuration example of a vibration type actuator having a form different from that of Embodiment 1 will be described with reference to FIG. 12. In this embodiment, as compared with Embodiment 1, the intermediate member 633 is configured to be composed of three layers as shown in FIG. 12, which is different from the structure shown in FIG. 1. Since the other elements of this embodiment are the same as the corresponding ones of Embodiment 1 described above, the description is omitted by aligning the last two digits of the figure numbers.

[0085] Fig. 12(a) shows an exploded perspective view of the vibrating body 602 of the vibration type actuator of the present embodiment. Fig. 12(b) is a schematic diagram showing the drive frequency region and the frequency regions of its harmonic components.

[0086] As shown in Fig. 12(a), the intermediate member 633 provided between the elastic body 603 and the piezoelectric element 604 is composed of two flat plate portions 633A and a through-hole portion 633B. In Fig. 12(a), for the sake of explanation, it is shown as being divided into three parts, but actually it has an integral structure formed by a 3D printer or the like. Therefore, both surfaces on the elastic body 603 side and the piezoelectric element 604 side have a uniform planar shape and are in a form with slits (voids) inside. However, the intermediate member 633 may also be configured by adhering the three parts as shown in the figure.

[0087] The through-hole portion 633B has four elongated holes 633-1A, 633-1B, 633-2A, and 633-2B extending in the X direction. By fixing the elastic body 603, the intermediate member 633, and the piezoelectric element 604 with an adhesive respectively, the vibrating body 602 is formed.

[0088] The surfaces of the intermediate member 633 on the elastic body 603 side and the piezoelectric element 604 side have a uniform planar shape without holes or the like. Thereby, the adhesion between the intermediate member 633, the elastic body 603, and the piezoelectric element 604 becomes stronger, and the peeling of the adhesion can be prevented.

[0089] Also in this embodiment, similar to Embodiment 1, the elastic body 603 is formed with a thickness of 0.35 mm, the intermediate member 633 is formed with a thickness of 0.1 mm, and the piezoelectric element 604 is formed with a thickness of 0.3 mm. Note that the thickness of the two flat plate portions 633A of the intermediate member 633 is 0.025 mm, and the thickness of the through-hole portion 634B is 0.05 mm.

[0090] Further, the four long holes 633B-1A, 633B-1B, 633B-2A, and 633B-2B of the through-hole portion 634B of the intermediate member 633 are symmetrically provided with respect to axes parallel to the X-axis and the Y-axis passing through the center of the intermediate member 633. And the positions of the four long holes 633B-1A, 633B-1B, 633B-2A, and 633B-2B in the Y direction are provided near the positions of the nodes of mode C shown by the black lines in FIG. 9(b). For this reason, the rigidity near the nodes of mode C can be selectively reduced, the change in the resonance frequencies of mode A and mode B which are driving vibrations can be suppressed, and the resonance frequency of mode C can be significantly lowered.

[0091] As shown by f1 in FIG. 12(b), the range of the driving frequency is 107 kHz to 100 kHz. The resonance frequency fc of mode C which is an unnecessary vibration is 395 kHz, and it is a frequency lower than the region of the harmonic component 428 kHz to 400 kHz which is four times the driving frequency. Therefore, even when the vibration type actuator 600 is driven in the predetermined driving frequency range of 107 kHz to 100 kHz, the region of the harmonic component which is four times the driving frequency does not pass through the resonance frequency of mode C.

[0092] Thereby, the generation of the vibration of mode C which is an unnecessary vibration during the driving of the vibration type actuator 600 can be suppressed, the generation of abnormal noise can be suppressed, and the vibration type actuator 600 can be stably driven.

[0093] <Example 4> As Example 4, a configuration example of a vibration type actuator in a form different from Example 1 will be described with reference to FIG. 13. In this example, compared with Example 1, it is different from the structure shown in FIG. 1 in that the intermediate member 733 has a support portion extending in the X direction as shown in FIG. 13. Since the other elements of this example are the same as the corresponding ones of Example 1 described above, the description is omitted by aligning the last two digits of the figure numbers.

[0094] FIG. 13(a) shows a perspective view of the vibrating body 702 of the vibration type actuator of this example, and FIG. 13(b) shows a plan view of the intermediate member 733 as viewed from the piezoelectric element 703 side.

[0095] As shown in FIGS. 13(a) and (b), the intermediate member 733 provided between the elastic body 703 (not shown) and the piezoelectric element 704 has four long holes 733-1A, 733-1B, 733-2A, and 733-2B extending in the X direction. Also, at both ends in the X direction, it has support portions 733-4 extending in the X direction. By fixing the elastic body 703, the intermediate member 733, and the piezoelectric element 704 with an adhesive respectively, the vibrating body 702 is formed.

[0096] The intermediate member 733 uses a material with good thermal conductivity such as an aluminum alloy, and the four long holes 733-1A, 733-1B, 733-2A, 733-2B and the outer shape are formed by pressing, etching, etc.

[0097] The support portion 733-4 is provided with a connecting long hole 733-4A and a connecting hole 733-4B that are connected to a holding member or the like for fixing the vibrating body 702. Thereby, the heat generated by the vibrating body 702 during the driving of the vibration type actuator 700 can be reduced by heat transfer to the external housing through the support portion 733-4. Therefore, in applications where heat dissipation by air cannot be suppressed, such as driving in a vacuum environment of a satellite or the like, heat dissipation by heat transfer is particularly effective as in this configuration.

[0098] Also, in order to firmly fix with the two connecting holes 733-4A and 733-4B, stable driving of the vibrating body is possible even when a high thrust is generated.

[0099] Note that the support portion 733-4 is partially thin in the Y direction in order to realize a flexible support structure that does not inhibit the vibration of the vibrating body 702.

[0100] Also in this embodiment, the four long holes 733-1A, 733-1B, 733-2A, and 733-2B of the intermediate member 733 are symmetrically provided with respect to the L1 axis and the L2 axis, which are axes parallel to the X axis and the Y axis passing through the center of the intermediate member 733, respectively. And the positions of the four long holes 733-1A, 733-1B, 733-2A, and 733-2B in the Y direction are provided near the positions of the nodes of mode C shown by the black lines in Fig. 9(b). Therefore, the rigidity near the nodes of mode C can be selectively reduced, the change in the resonance frequencies of driving vibrations, mode A and mode B, can be suppressed, and the resonance frequency of mode C can be significantly lowered.

[0101] Therefore, the generation of vibrations in mode C, which are unnecessary vibrations during the driving of the vibration type actuator 700, can be reduced, the generation of abnormal noises can be reduced, and the vibration type actuator 700 can be stably driven.

[0102] <Example 5> Fig. 14 is a top view showing a schematic configuration of an imaging device 360, which is an example of an optical device including the vibration type actuator 100 of the present invention. The imaging device 360 has an imaging device main body 361 having an imaging element (not shown) on which light passing through a lens described later is imaged, and a lens barrel 362 that is detachable from the imaging device main body 361. The lens barrel 362 includes a plurality of lens groups 363 (lenses), a focus adjustment lens 364 (lens), and the vibration type actuator 100. A lens holding frame (not shown) that holds the focus adjustment lens 364 is connected to the contact body holder 10, which is a moving body in the vibration type actuator 100. By driving the vibration type actuator 100, the focus adjustment lens 364, which is an example of an optical element, can be driven in the optical axis direction to focus on a subject.

[0103] Note that the vibration type actuator 100 can also be used as a drive source for moving the zoom lens in the optical axis direction when the zoom lens is disposed in the lens barrel 362. Further, when the image blur correction lens is disposed in the lens barrel 362, the vibration type actuator 100 can be used as a drive source for driving the image blur correction lens in a plane orthogonal to the optical axis.

[0104] <Example 6> FIG. 15 is a perspective view showing a schematic configuration of a microscope 1000 (stage device), which is an example of an electronic apparatus including the vibration type actuator of the present invention.

[0105] In Example 6, as an example of an apparatus including at least two or more of the vibration type actuators according to Example 1 described above, the configuration of a microscope 1000 including an X-Y stage will be described with reference to FIG. 15. FIG. 15 is an external perspective view of the microscope 1000.

[0106] The microscope 1000 includes an imaging unit 1010 incorporating an imaging device (not shown) and an optical system, and an automatic stage 1030. The automatic stage 1030 includes a base, a first vibration type actuator (not shown) and a second vibration type actuator (not shown) provided on the base, and a stage 1020 that moves within the X-Y plane provided on the base. Each of the first vibration type actuator and the second vibration type actuator uses the vibration type actuator 100 of Example 1.

[0107] The first vibration type actuator is used as a driving device for driving a stage 1020, which is an example of a member driven by the vibration type actuator, in the X direction of the stage 1020. Further, the first vibration type actuator is arranged such that the direction of relative movement between the vibrating body 2 and a part of the contact body 9 coincides with the X direction of the stage 1020.

[0108] Further, the second vibration type actuator is used as a driving device that drives the stage 1020 in the Y direction of the stage 1020. Further, the second vibration type actuator is arranged such that the direction of relative movement between the vibrating body 2 and a part of the contact body 9 coincides with the Y direction of the stage 1020.

[0109] An object to be observed is placed on the upper surface of the stage 1020, and a magnified image is taken by the imaging unit 1010. When the observation range is wide, the first vibration type actuator and the second vibration type actuator are used to drive the automatic stage 1030 to move the stage 1020 in the in-plane direction to move the object to be observed, thereby changing the imaging region. By combining the images taken in different imaging regions by image processing using a computer (not shown), it is possible to obtain a single high-definition image with a wide observation range.

[0110] As described above, the present invention has been described in detail based on its preferred embodiments. However, the present invention is not limited to these specific embodiments, and various forms within the scope not departing from the gist of the present invention are also included in the present invention. Furthermore, each of the above-described embodiments merely shows one embodiment of the present invention, and it is also possible to appropriately combine the embodiments.

[0111] The disclosure of this embodiment includes the following configurations and methods.

[0112] (Configuration 1) A vibrating body having an elastic body and an electro-mechanical energy conversion element, A contact body that is pressurized and contacts the vibrating body, A vibration type actuator that relatively moves the vibrating body and the contact body by vibration of the vibrating body, An intermediate member is provided between the elastic body and the electro-mechanical energy conversion element, The vibration type actuator, wherein the intermediate member has at least one of a through hole, a groove, or a slit.

[0113] (Configuration 2) The vibration type actuator according to Configuration 1, wherein the elastic body and the intermediate member have a rectangular and flat plate shape.

[0114] (Configuration 3) The elastic body has a contact portion that contacts the contact body, The intermediate member is adhered to a surface opposite to the surface having the contact portion of the elastic body in the pressing direction in which the vibrating body is pressed against the contact body, and the electro-mechanical energy conversion element is adhered to a surface opposite to the adhesion surface of the intermediate member with the elastic body in the pressing direction. The vibration type actuator according to Configuration 1 or 2, characterized in that.

[0115] (Configuration 4) The through hole of the intermediate member is a through hole that penetrates from the adhesion surface of the intermediate member with the elastic body to the adhesion surface with the electro-mechanical energy conversion element. The vibration type actuator according to Configuration 3, characterized in that.

[0116] (Configuration 5) The groove of the intermediate member has an opening on the adhesion surface of the intermediate member with the elastic body, The adhesion surface of the intermediate member with the electro-mechanical energy conversion element has a uniform planar shape. The vibration type actuator according to Configuration 3 or 4, characterized in that.

[0117] (Configuration 6) The intermediate member is composed of a plurality of flat plates, The plurality of flat plates are adhered to the elastic body and the electro-mechanical energy conversion element with a gap between each of them, so that a slit of the intermediate member is formed. The vibration type actuator according to any one of Configurations 3 to 4, characterized in that.

[0118] (Configuration 7) The through hole, groove, or slit of the intermediate member is provided at a position symmetric with respect to an axis in the direction of relative movement passing through the center of the intermediate member and an axis in a direction orthogonal to the direction of relative movement and the pressing direction, respectively. The vibration type actuator according to any one of Configurations 1 to 6.

[0119] (Configuration 8) The through hole, groove, or slit of the intermediate member is provided in the vicinity of a node of a vibration different from the vibration used for driving the vibration type actuator. The vibration type actuator according to any one of Configurations 1 to 7.

[0120] (Configuration 9) The through hole, groove, or slit of the intermediate member has a long hole shape extending in the direction of relative movement. The vibration type actuator according to any one of Configurations 1 to 8.

[0121] (Configuration 10) The intermediate member has a plurality of through holes, The plurality of through holes are provided side by side along the direction of relative movement. The vibration type actuator according to any one of Configurations 1 to 9.

[0122] (Configuration 11) The vibration type actuator according to any one of Configurations 1 to 10, An optical device comprising at least one of an optical element or an imaging element driven by the vibration type actuator.

[0123] (Configuration 12) A member, An electronic device comprising the vibration type actuator according to any one of Configurations 1 to 10 for driving the member.

Explanation of Reference Numerals

[0124] 2 Vibration body 3 Elastic body 33 Intermediate member 4 Piezoelectric element (electrical-mechanical energy conversion element) 6 Holding member 9 Contact body

Claims

1. A vibrating body having an elastic body and an electro-mechanical energy conversion element, A contact body that is pressed against and in contact with the vibrating body, and comprising: A vibration type actuator that relatively moves the vibrating body and the contact body by vibration of the vibrating body, An intermediate member is provided between the elastic body and the electro-mechanical energy conversion element, The intermediate member has at least one of a through hole, a groove, or a slit, and is a vibration type actuator characterized by this.

2. The vibration type actuator according to claim 1, wherein the elastic body and the intermediate member have a rectangular and flat plate shape.

3. The elastic body has a contact portion that contacts the contact body, The intermediate member is adhered to a surface opposite to the surface where the contact portion of the elastic body is located in the pressing direction in which the vibrating body is pressed against the contact body, and the electro-mechanical energy conversion element is adhered to a surface opposite to the adhesion surface of the intermediate member with the elastic body in the pressing direction. The vibration type actuator according to claim 1 or 2, characterized by this.

4. The through hole of the intermediate member is a through hole that penetrates from the adhesion surface of the intermediate member with the elastic body to the adhesion surface with the electro-mechanical energy conversion element, and is a vibration type actuator characterized by this according to claim 3.

5. The groove of the intermediate member has an opening on the adhesion surface of the intermediate member with the elastic body, The adhesion surface of the intermediate member with the electro-mechanical energy conversion element has a uniform planar shape, and is a vibration type actuator characterized by this according to claim 3.

6. The intermediate member is composed of a plurality of flat plates, The plurality of flat plates are adhered to the elastic body and the electro-mechanical energy conversion element with a gap between each of them, and the slit of the intermediate member is formed, and is a vibration type actuator characterized by this according to claim 3.

7. The through hole, the groove, or the slit of the intermediate member is provided at a symmetric position with respect to an axis in the direction of the relative movement passing through the center of the intermediate member, and an axis in a direction orthogonal to the direction of the relative movement and the pressing direction. The vibration type actuator according to claim 1, characterized by this.

8. The vibration type actuator according to claim 1, wherein the through hole, the groove, or the slit of the intermediate member is provided near a node of a vibration different from the vibration used for driving the vibration type actuator.

9. The vibration type actuator according to claim 1, wherein the through hole, the groove, or the slit of the intermediate member has a long hole shape extending in the direction of the relative movement.

10. The intermediate member has a plurality of through holes, The vibration type actuator according to claim 1, wherein the plurality of through holes are provided side by side along the direction of the relative movement.

11. A vibration type actuator according to any one of claims 1 to 10, An optical device comprising at least one of an optical element or an imaging element driven by the vibration type actuator.

12. A member, An electronic device comprising the vibration type actuator according to any one of claims 1 to 10 for driving the member.

Images