Vibration wave driving device and imaging device

Abstract

To provide a compact vibration wave drive apparatus which can suppress a deterioration of an output transmitted to the outside.SOLUTION: A vibration wave drive apparatus includes a vibration actuator and a drive target body driven by the vibration actuator. The vibration actuator includes: a vibrator having an electro-mechanical energy conversion element and an elastic body to which the electro-mechanical energy conversion element is fixed; a pressure member which presses the vibrator; a contact body which makes pressure contact with the vibrator by the pressure of the pressure member to the vibrator, and moves relatively to the vibrator; and an output part which outputs to the drive target body a drive force generated by the relative movement of the contact body to the vibrator. The drive target body includes an output transmission part which holds the output part with a predetermined spring force in the relative movement direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a vibration wave driving device and an imaging device.

Background Art

[0002] Vibration wave driving devices using electro-mechanical energy conversion elements such as piezoelectric elements that convert electrical energy into mechanical energy are known in various configurations. For example, a vibration wave driving device is known that includes a contact body, a vibrator in which two protrusions are provided on the surface of a flat elastic body and a piezoelectric element is bonded to the back surface of the elastic body, and a pressing member for pressing the two protrusions into pressure contact with the contact body. Here, the back surface of the elastic body refers to the surface where no protrusions are formed as described later.

[0003] In this vibration wave driving device, by applying a predetermined alternating voltage (hereinafter also referred to as "driving voltage") to the electro-mechanical energy conversion element, an elliptical motion or a circular motion is generated at the tips of the two protrusions in a plane including the direction connecting the two protrusions and the protruding direction of the protrusions. As a result, the contact body receives a frictional driving force from the two protrusions (vibrator), and the vibrator and the contact body can be relatively moved (hereinafter also referred to as "relative movement") in the direction connecting the two protrusions.

[0004] Various proposals have been made for a mechanism (output transmission mechanism) for transmitting the output from this vibration wave driving device to the outside. For example, in Patent Document 1, the output is transmitted to the AF ring by loosely fitting, press-fitting, or screwing a connecting portion to a protrusion extending in the pressing direction from the mover. On the other hand, in Patent Document 2, the output is transmitted to the outside by pressing a V-grooved portion against a protrusion extending in the pressing direction from a holding member by the force of a torsion spring.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the output transmission mechanism disclosed in Patent Document 1, in the case of a rattling configuration, misalignment occurs between the mover and the AF ring which is the driven body, thus adversely affecting the stop accuracy. Further, when the output transmission mechanism is fastened by press-fitting or screwing, although the stop accuracy is good, due to the error in the parallelism of the moving axes of the driven body and the mover, an excessive force is applied to the vibration wave drive device or the driven body side, which may cause a decrease in the output transmitted to the outside and deterioration of durability.

[0007] On the other hand, in the technology of Patent Document 2, the output is transmitted to the outside by pressing the V-grooved portion against the protrusion on the vibration wave drive device side by the force of the torsion spring, thereby eliminating rattling and ensuring stop accuracy while absorbing the error in the parallelism of the moving axes of the driven body and the vibration wave drive device. However, in this configuration, the protrusion and the vibration wave drive device are subjected to forces in the pressing direction or other directions. As described above, since the vibration wave drive device generates output by pressing the vibrator against the contact body, the pressing force of the V-grooved portion needs to be applied to a location not affected by the pressing force applied to this vibrator. Therefore, in the technology of Patent Document 2, there were cases where miniaturization of the device could not be achieved due to design constraints.

[0008] One embodiment of the present invention has been made in view of such problems, and one of the objectives is to provide a vibration wave drive device that is small-sized and capable of suppressing a decrease in the output transmitted to the outside.

Means for Solving the Problems

[0009] A vibration wave driving device according to an embodiment of the present invention includes a vibration type actuator and a driven body driven by the vibration type actuator. The vibration type actuator includes an electro-mechanical energy conversion element, a vibrator having an elastic body to which the electro-mechanical energy conversion element is fixed, a pressing member for pressing the vibrator, a contact body that comes into pressure contact with the vibrator when the pressing member presses the vibrator and relatively moves with respect to the vibrator, and an output unit that outputs a driving force generated when the contact body relatively moves with respect to the vibrator to the driven body. The driven body includes an output transmission unit that holds the output unit with a predetermined spring force in the direction of the relative movement.

Effect of the Invention

[0010] According to an embodiment of the present invention, it is possible to provide a vibration wave driving device that is small in size and can suppress a decrease in output transmitted to the outside.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Best Mode for Carrying Out the Invention

[0012] Hereinafter, exemplary embodiments for carrying out the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative positions of the components, etc. described in the following embodiments are arbitrary and can be changed according to the configuration of the device to which the present invention is applied or various conditions. Also, in the drawings, the same reference numerals are used between the drawings to indicate elements that are the same or functionally similar.

[0013] (Example 1) As Example 1 of the present invention, an example in which the present invention is applied to a linear vibration wave driving device will be described. Hereinafter, the linear vibration wave driving device according to this embodiment will be described with reference to FIGS. 1 to 8. First, the details of the vibration wave motor of the linear vibration wave driving device will be described using FIGS. 1 to 2(d). FIG. 1 is an exploded perspective view of the vibration wave motor 1 according to this embodiment, and FIGS. 2(a) to 2(d) are assembly views of the vibration wave motor 1. Specifically, FIG. 2(a) is a perspective view of the vibration wave motor 1, and FIG. 2(b) is an XZ plan view of the vibration wave motor 1. Also, FIG. 2(c) is an XZ cross-sectional view of the vibration wave motor 1 taken along line 2C-2C of FIG. 2(a), and FIG. 2(d) is a YZ cross-sectional view of the vibration wave motor 1 taken along line 2D-2D of FIG. 2(c). Here, the relative movement direction of the vibrator 2 is defined as the X direction, the pressing direction is defined as the Z direction, and the direction orthogonal to the X direction and the Z direction is defined as the Y direction. In this specification, up and down respectively correspond to the upward and downward directions in the Z direction.

[0014] The vibration wave motor 1 is provided with an elastic body 3, a piezoelectric element 4, a flexible printed circuit board 5, a holding member 6, a compression spring 7, a friction member 8, rubber 9, a first guide member 10, a second guide member 12, a screw 13, and a base 14. The elastic body 3 is provided with a rectangular main body portion 3c and a plurality (here, four) of extending portions 3b extending from a plurality (here, two positions) of positions in the X direction of the main body portion 3c. The plurality of extending portions 3b protrude from a plurality (here, four positions) of positions of the main body portion 3c, the positions of which are different in the X direction and the Y direction, respectively.

[0015] A piezoelectric element 4, which is an electro-mechanical energy conversion element, is fixed to the elastic body 3 with an adhesive or the like. Further, a flexible printed circuit board 5 is fixed to the opposite surface of the piezoelectric element 4 where the elastic body 3 is fixed. Here, the elastic body 3, the piezoelectric element 4, and the flexible printed circuit board 5 constitute a vibrator 2. Note that the piezoelectric element 4 and the flexible printed circuit board 5 can be fixed using an anisotropic conductive paste or an anisotropic conductive film that enables energization only in the Z direction.

[0016] As the material of the elastic body 3, a material with low vibration attenuation such as metal or ceramics can be used. Regarding the manufacture of the elastic body 3, the protrusion 3a may be integrally provided by press molding or cutting, or the protrusion 3a may be separately manufactured and then fixed to the elastic body 3 by welding or adhesion. Further, a plurality of protrusions 3a may be provided as in this embodiment, or only one protrusion 3a may be provided.

[0017] The piezoelectric element 4 can be configured using lead zirconate titanate. Further, the piezoelectric element 4 may be mainly composed of a piezoelectric material containing no lead such as barium titanate or sodium bismuth titanate. Electrode patterns (not shown) are formed on both surfaces of the piezoelectric element 4, and power is supplied from the flexible printed circuit board 5 using the electrode patterns.

[0018] Here, the pressurizing mechanism according to this embodiment will be described. Below the vibrator 2, a holding member 6 for pressurizing and holding the vibrator 2 is provided, and above the vibrator 2, a second guide member 12 is provided. The two pressurizing fulcrums 6e provided at one end of the holding member 6 in the X direction and the two fitting portions 12b provided on the second guide member 12 are rotatably fitted around the Y-axis direction. Also, a pressurizing spring 7 is provided between the spring installation portion 6f provided at the other end of the holding member 6 in the X direction and the second guide member 12. As the pressurizing spring 7, for example, a tension coil spring can be used. At substantially the central position in the X direction between the pressurizing fulcrum 6e and the pressurizing spring 7 on the holding member 6, two convex portions 6a are provided, and the two convex portions 6a are in contact with the vibrator 2.

[0019] Thus, in the pressurizing mechanism according to this embodiment, based on the lever principle with the pressurizing fulcrum 6e as the fulcrum, the spring installation portion 6f as the effort point, and the convex portion 6a as the point of application, a pressing force is applied to the vibrator 2 in the Z direction. Also, above the vibrator 2, a friction member 8 (hereinafter also referred to as a "contact body") is provided, and due to the pressing force applied to the vibrator 2 by the pressurizing mechanism, it is in pressurized contact with the protrusion 3a of the elastic body 3 in the Z direction. With such a pressurizing mechanism, the vibrator 2, the holding member 6, and the second guide member 12 can move integrally in the X direction.

[0020] Also, as shown in FIG. 2(c), an output portion 6d is provided on the surface of the holding member 6 opposite to the convex portion 6a. The vibration wave motor 1 can output the driving force generated by the movement of the vibrator 2 to the outside through the output portion 6d of the holding member 6. In this embodiment, the pressurizing fulcrum 6e is provided at one end of the holding member 6 in the X direction, and the spring installation portion 6f is provided at the other end. However, the pressurizing fulcrum 6e and the spring installation portion 6f are not limited to being provided at the ends of the holding member 6 in the X direction, and each may be provided at a position where it can function as the fulcrum and the effort point of the lever principle with the convex portion 6a as the point of application. Also, the flexible printed circuit board 5 can be fixed to the flexible base 6b of the holding member 6 with double-sided tape or the like.

[0021] Above the contact body 8, a rubber 9, a first guide member 10, and a second guide member 12 are provided. The contact body 8 is fixed to the first guide member 10 by the adsorption force of the rubber 9. The rubber 9 also plays a role of vibration damping, making it difficult to transmit the vibration from the vibrator 2 to the first guide member 10. Further, the first guide member 10 is fixed to a base 14, which is a fixing member, by a screw 13. Note that the fixing method of the contact body 8 to the first guide member 10 and the rubber 9 may be adhesion or screwing. Also, the contact body 8 can be configured using a highly wear-resistant metal, ceramic, resin, or a composite material thereof. In particular, as the material of the contact body 8, from the viewpoints of wear resistance and mass productivity, a material obtained by nitriding stainless steel such as SUS420J2 can be used.

[0022] Subsequently, the linear guide mechanism according to this embodiment will be described. The first guide member 10 and the second guide member 12 are each provided with two rolling grooves 10a and 12a, which sandwich two balls 11 therebetween. By doing so, when driving the vibration wave motor 1, the balls 11 roll in the rolling grooves 10a and 12a, so that the vibrator 2, the holding member 6, and the second guide member 12 can move smoothly in the X direction. Regarding the materials of the first guide member 10 and the second guide member 12, hardness is required because they are pressurized in the respective rolling grooves 10a and 12a. In addition, from the viewpoint of workability, metal, particularly stainless steel, can be used.

[0023] The base 14 is provided with two fixing portions 14a having screw holes and retaining portions for fixing the first guide member 10, holes for fixing the base 14 to the outside, a connecting portion 14b connecting them, a groove portion 14c, and a collision prevention portion 14d. The groove portion 14c is formed along the X direction in a part of the connecting portion 14b. By the groove portion 14c and the inclination restricting portion 12c provided on the second guide member 12 being loosely fitted, that is, fitting in a state having a predetermined play, the rotation of the vibrator 2 and the like around the X axis can be restricted. The collision prevention portion 14d extends from the fixing portion 14a toward the holding member 6 in the X direction, and can prevent the pressing fulcrum 6e and the spring installation portion 6f of the holding member 6 from colliding with the fixing portion 14a as the holding member 6 moves. Note that the base 14 can be formed of resin from the viewpoints of workability and slidability.

[0024] Further, a flexible printed circuit board 5 is fixed to the connecting portion 14b. For this reason, the base 14 also has a function of accommodating the curved portion of the flexible printed circuit board 5 that moves while curving as the vibrator 2 and the holding member 6 move.

[0025] Next, with reference to FIGS. 3(a) and 3(b), the vibration modes excited in the vibrator 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 standing waves (out-of-plane bending vibrations) having different phases in the vibrator 2, and vibrations obtained by synthesizing these out-of-plane bending vibrations are generated. FIG. 3(a) shows the vibrator 2 driven in mode A which is the first vibration mode, and FIG. 3(b) shows the vibrator 2 driven in mode B which is the second vibration mode. Note that in FIGS. 3(a) and 3(b), the flexible printed circuit board 5 is omitted for simplicity of explanation and the vibrator 2 is shown.

[0026] 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 vibrator 2. Due to the vibration of Mode A, the two protrusions 3a 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 vibrator 2. Due to the vibration of Mode B, the two protrusions 3a are displaced in the X direction.

[0027] By synthesizing the vibrations of these Mode A and Mode B, the two protrusions 3a perform elliptical or circular motion within the XZ plane. By bringing the contact member 8 into pressure contact with the protrusions 3a, a frictional force is generated in the X direction, and a driving force (thrust force) for relatively moving the vibrator 2 and the contact member 8 is generated. In this embodiment, since the contact member 8 is fixed to the base 14 as described above, the vibrator 2 moves in the X direction.

[0028] In order to efficiently drive the vibration wave motor 1, it is necessary to support the vibrator 2 without inhibiting the vibrations (displacements) of the two vibration modes excited in the vibrator 2. For this purpose, it is desirable to support the vicinity of the nodes of these two vibration modes. For this reason, two convex portions 6a are provided on the holding member 6 in order to press and hold the common node of the two vibration modes excited in the vibrator 2. Further, by positioning the vibrator 2 with the retaining portion 6c provided on the retaining member 6, the two convex portions 6a can be brought into contact with the vibrator 2 in the vicinity of the nodes of the two vibration modes, respectively.

[0029] Furthermore, the convex portion 6a not only presses the vibrator 2 but also holds the vibrator 2 in the X and Y directions by frictional force. In this embodiment, since the maximum value of the static frictional force between the convex portion 6a and the vibrator 2 is always greater than the reaction force received by the vibrator 2 from the contact member 8 when driving the vibrator 2, the vibrator 2 does not move relative to the holding member 6. As a result, precise driving can be performed.

[0030] Next, with reference to FIGS. 4 to 5(b), the output transmission mechanism according to this embodiment will be described. FIG. 4 is an XZ cross-sectional view of the vibration wave motor 1 and the output transmission unit 18 according to this embodiment. FIG. 5(a) is a perspective view of the output transmission unit 18, and FIG. 5(b) is an XZ plan view of the output transmission unit 18.

[0031] The output transmission unit 18 according to this embodiment is provided with a first gripping member 15, a second gripping member 16, and a torsion spring 17. The first gripping portion 15a of the first gripping member 15 and the second gripping portion 16a of the second gripping member 16 sandwich the output portion 6d. The second gripping member 16 is rotatably fitted to the first gripping member 15 around the Y-axis, and a gripping force is applied around the Y-axis while being biased in the Y-axis direction with a predetermined force by the torsion spring 17.

[0032] Since this gripping force is larger than the thrust generated by the vibration wave motor 1, precise driving of the driven body can be performed without play occurring between the vibration wave motor 1 and the driven body connected to the output transmission unit 18. Also, because the output portion 6d is configured to be gripped in the X direction, which is the traveling direction of the vibrator 2, stable driving can be performed without affecting the pressing force applied to the vibrator 2.

[0033] Next, with reference to FIGS. 6(a) to 7, the configuration during assembly will be described. FIG. 6(a) is an XZ cross-sectional view of the output transmission unit 18 of the vibration wave driving device in a temporarily fixed state, and FIG. 6(b) is an XZ cross-sectional view of the output transmission unit 18 of the vibration wave driving device in an assembled state. FIG. 7 is an XY cross-sectional view of the output transmission unit 18 of the vibration wave driving device according to the line A-A in FIG. 6(b).

[0034] The first gripping member 15 is provided with two first temporary fixing holes 15b, and the second gripping member 16 is provided with a second temporary fixing hole 16b. The first temporary fixing hole 15b and the second temporary fixing hole 16b are arranged substantially coaxially, and a temporary fixing pin (not shown) is passed through these first temporary fixing holes 15b and the second temporary fixing hole 16b. Thereby, the gap between the two gripping portions can be maintained in a state where it is wider than the width of the output portion 6d, that is, a temporary fixing state without applying a gripping force. In this state, the output portion 6d of the vibration wave motor 1 is arranged between the first gripping portion 15a and the second gripping portion 16a as shown in FIG. 6(a), and the vibration wave motor 1 is fixed to another member by screwing the fixing portion 14a. Subsequently, the temporary fixing is released by pulling out the temporary fixing pin (not shown), and as shown in FIG. 6(b), a gripping force is applied to the output portion 6d by the first gripping portion 15a and the second gripping portion 16a. By using temporary fixing in this way, the output transmission mechanism of this embodiment can also be assembled efficiently.

[0035] Next, the contact shape with the output portion 6d in each gripping member will be described. As shown in FIG. 6(b), in the XZ cross section, the contact surfaces of the first gripping portion 15a and the second gripping portion 16a with the output portion 6d are curved surfaces. Thereby, even if an assembly error around the Y axis occurs between the vibration wave motor 1 and each gripping member, it is possible to reduce the application of unnecessary force to the holding member 6. Also, as shown in FIG. 7, in the XY cross section of the portion where the output portion 6d is being gripped, conversely, the output portion 6d is curved, and the first gripping portion 15a and the second gripping portion 16a are linear contact portions. Thereby, even if an assembly error around the Z axis occurs between the vibration wave motor 1 and each gripping member, it is possible to reduce the application of unnecessary force to the holding member 6.

[0036] Finally, a method for driving the driven body 19 by the vibration wave motor 1 and the output transmission unit 18 according to this embodiment will be described with reference to FIG. 8. FIG. 8 shows an example of a lens component incorporating a vibration wave driving device. Here, as an example of the driven body 19, an example will be described in which a lens ring that receives the moving shaft 20 and is movable along the moving shaft 20 is used. The output transmission unit 18 is fixed to a part of the driven body 19 by screws or the like. On the other hand, the vibration wave motor 1 is fixed to a fixing base (not shown) by screws. At this time, the output unit 6d of the vibration wave motor 1 and the output transmission unit 18 are coupled by the method described with reference to FIGS. 6(a) and 6(b).

[0037] When the vibration wave motor 1 is driven, the driving unit (the vibrator 2, the holding member 6, the second guide member 12, and the compression spring 7) of the vibration wave motor 1, the output transmission unit 18, and the driven body 19 move integrally in the X direction. At this time, even if an error occurs in the parallelism between the moving shaft 20 of the driven body 19 and the driving unit of the vibration wave motor 1, the output unit 6d, the first gripping part 15a, and the second gripping part 16a are constrained only in the X-axis direction, and only frictional force acts in the Z-axis and Y-axis directions. Therefore, fluctuations in the pressing force acting on the vibrator 2 can be minimized. From such a viewpoint, as the material of the output unit 6d, the first gripping part 15a, and the second gripping part 16a, a material with a low friction coefficient can be selected. Also, for example, it is effective to apply a lubricant such as grease to these parts.

[0038] As described above, the vibration wave driving device according to this embodiment includes a vibration wave motor 1 that functions as an example of a vibration type actuator, and a driven body 19 driven by the vibration wave motor 1. The vibration wave motor 1 includes a piezoelectric element 4, a vibrator 2 having an elastic body 3 to which the piezoelectric element 4 is fixed, and a pressing member that presses the vibrator 2. Here, the piezoelectric element 4 functions as an example of an electro-mechanical energy conversion element that converts electrical energy into mechanical energy. Further, the vibration wave motor 1 includes a contact body 8 that comes into pressure contact with the vibrator 2 and relatively moves with respect to the vibrator 2 when the pressing member presses the vibrator 2. Furthermore, the vibration wave motor 1 includes an output unit 6d that outputs a driving force generated when the contact body 8 relatively moves with respect to the vibrator 2 to the driven body 19. The driven body 19 includes an output transmission unit 18 that grips the output unit 6d with a predetermined spring force in the direction of relative movement.

[0039] Thus, in the vibration wave driving device according to this embodiment, an output transmission unit that grips a part of the holding member of the linear vibration wave motor with a predetermined spring force in the X direction, which is the direction of relative movement, is employed. Thereby, it is possible to provide a vibration wave driving device that is small in size and can suppress a decrease in the output transmitted to the outside.

[0040] Further, the output transmission unit 18 includes a first gripping member 15, a second gripping member 16 different from the first gripping member 15, and a torsion spring 17 that functions as an example of a gripping force applying means that presses the second gripping member 16. The output transmission unit 18 grips the output unit 6d by the first gripping member 15 and the second gripping member 16. On the other hand, when the first temporary fixing hole 15b provided in the first gripping member 15 and the second temporary fixing hole 16b provided in the second gripping member 16 are arranged substantially coaxially, the output transmission unit 18 does not grip the output unit 6d. Therefore, at the time of assembling the device, the device can be efficiently assembled by utilizing the fact that the first temporary fixing hole 15b and the second temporary fixing hole 16b are arranged substantially coaxially to make the output transmission unit 18 in a temporarily fixed state.

[0041] Further, the contact portions of the first gripping member 15 and the second gripping member 16 with the output portion 6d are curved when viewed in a cross section along the relative movement direction and the pressing direction. Thereby, even if an assembly error around the Y-axis occurs between the vibration wave motor 1 and each gripping member, it is possible to reduce the application of unnecessary force to the holding member 6. Further, the contact portions of the first gripping member 15 and the second gripping member 16 with the output portion 6d are linear when viewed in a cross section along the direction orthogonal to the relative movement direction and the relative movement direction, and the output portion 6d is curved. Thereby, even if an assembly error around the Z-axis occurs between the vibration wave motor 1 and each gripping member, it is possible to reduce the application of unnecessary force to the holding member 6.

[0042] Further, the pressing member further includes a holding member 6 that holds the vibrator 2, a second guide member 12 that functions as an example of a guide member that guides the relative movement between the vibrator 2 and the contact body 8, and a biasing member that biases the holding member 6 and the second guide member 12 with respect to each other. Here, the compression spring 7 functions as an example of the biasing member. The vibrator 2 and the contact body 8 are disposed between the holding member 6 and the second guide member 12. The pressing member presses the vibrator 2 by biasing the holding member 6 and the second guide member 12 with respect to each other by the compression spring 7. Thereby, the pressing member can guide the relative movement between the vibrator 2 and the contact body 8 by the second guide member 12 while pressing the vibrator 2.

[0043] In the linear vibration wave motor 1 of the present invention, the method of generating elliptical motion or circular motion on the contact surface is not limited to the above method. For example, vibrations in different bending vibration modes may be combined, or a combination of longitudinal vibration mode vibrations that expand and contract the elastic body 3 in the longitudinal direction and bending vibration mode vibrations may be used. Any driving method may be used as long as it has a common node for pressing and holding, in a method of generating elliptical motion and circular motion on the contact surface by combining a vibration mode that displaces the contact surface in the moving direction of the contact body 8 and a vibration mode that displaces the contact surface in the pressing direction.

[0044] (Example 2) The vibration wave driving device can be used, for example, for lens driving applications of an imaging device (optical device, electronic device). Therefore, with reference to FIGS. 9(a) and 9(b), as Example 2 of the present invention, an example of an imaging device using the vibration wave driving device for driving a lens disposed in a lens barrel will be described.

[0045] FIG. 9(a) is a top view showing a schematic configuration of the imaging device 700. The imaging device 700 is provided with a camera body 730 on which an imaging element 710 and a power button 720 are mounted. Further, the imaging device 700 is provided with a lens barrel 740 having a first lens group (not shown), a second lens group 320, a third lens group (not shown), a fourth lens group 340, and vibration wave driving devices 620 and 640. The lens barrel 740 is replaceable as an interchangeable lens, and a lens barrel 740 suitable for the imaging object can be attached to the camera body 730. In the imaging device 700, the second lens group 320 and the fourth lens group 340 are respectively driven by two vibration wave driving devices 620 and 640.

[0046] The vibration wave driving device 620 has the same configuration as the vibration wave driving device according to Example 1. The driving unit and the output transmission unit 18 of the vibration wave motor 1 of the vibration wave driving device 620 are integrated with the second lens group 320 to move the second lens group 320 in the optical axis direction. Further, since the vibration wave driving device 640 has the same configuration as the vibration wave driving device 620, the fourth lens group 340 is moved in the optical axis direction.

[0047] FIG. 9(b) is a block diagram showing a schematic configuration of the imaging device 700. Inside the lens barrel 740, a first lens group 310, a second lens group 320, a third lens group 330, a fourth lens group 340, and a light amount adjustment unit 350 are arranged at predetermined positions on the optical axis. The light that has passed through the first lens group 310 to the fourth lens group 340 and the light amount adjustment unit 350 forms an image on the imaging element 710. The imaging element 710 converts the optical image into an electrical signal, outputs it, and sends it to the camera processing circuit 750.

[0048] The camera processing circuit 750 performs amplification, gamma correction, etc. on the output signal from the imaging device 710. The camera processing circuit 750 is connected to the CPU 790 via the AE gate 755 and is also connected to the CPU 790 via the AF gate 760 and the AF signal processing circuit 765. The video signal subjected to predetermined processing in the camera processing circuit 750 is sent to the CPU 790 through the AE gate 755, the AF gate 760, and the AF signal processing circuit 765. Note that the AF signal processing circuit 765 extracts the high-frequency components of the video signal, generates an evaluation value signal for autofocus (AF), and supplies the generated evaluation value to the CPU 790.

[0049] The CPU 790 is a control circuit that controls the overall operation of the imaging device 700 and generates control signals for exposure determination and focusing from the acquired video signal. The CPU 790 controls the driving of the vibration wave driving devices 620, 640, and the meter 630 so as to obtain the determined exposure and an appropriate focus state, thereby adjusting the optical axis direction positions of the second lens group 320, the fourth lens group 340, and the light quantity adjustment unit 350. Under the control of the CPU 790, the vibration wave driving device 620 moves the second lens group 320 in the optical axis direction, the vibration wave driving device 640 moves the fourth lens group 340 in the optical axis direction, and the meter 630 drives and controls the light quantity adjustment unit 350.

[0050] The optical axis direction position of the second lens group 320 driven by the vibration wave driving device 620 is detected by the first linear encoder 770, and the detection result is notified to the CPU 790, whereby it is fed back to the driving of the vibration wave driving device 620. Similarly, the optical axis direction position of the fourth lens group 340 driven by the vibration wave driving device 640 is detected by the second linear encoder 775, and the detection result is notified to the CPU 790, whereby it is fed back to the driving of the vibration wave driving device 640. The optical axis direction position of the light quantity adjustment unit 350 is detected by the aperture encoder 780, and the detection result is notified to the CPU 790, whereby it is fed back to the driving of the meter 630.

[0051] As described above, the imaging device 700 according to this embodiment includes vibration wave driving devices 620 and 640 having the same configuration as that of the first embodiment, an imaging element 710, and a CPU 790 that functions as an example of a control unit that controls the piezoelectric elements 4 of the vibration wave driving devices 620 and 640. Further, the imaging device 700 includes a second lens group 320 and a fourth lens group 340 as driven bodies.

[0052] With such a configuration, the imaging device 700 can perform autofocus using the vibration wave driving devices 620 and 640. Further, by using the vibration wave driving devices 620 and 640, it is possible to relax the design constraints of the imaging device 700 and facilitate miniaturization and the like.

[0053] As described above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to the above embodiments. The invention modified within the scope not contrary to the gist of the present invention and the invention equivalent to the present invention are also included in the present invention. Further, each of the above-described embodiments and modified examples can be appropriately combined within the scope not contrary to the gist of the present invention.

Explanation of Reference Numerals

[0054] 1: Vibration wave motor (vibratory actuator) 2: Vibrator 3: Elastic body 3a: Protrusion 3b: Extension 3c: Main body 4: Piezoelectric element (electromechanical energy conversion element) 5: Flexible printed circuit board 6: Holding member 6a: Convex portion 6b: Flexible base 6c: Anti-drop portion 6d: Output portion 6e: Pressing fulcrum 6f: Spring installation portion 7: Pressing spring 8: Contact body 9: Rubber 10: First guide member 10a: Rolling groove 11: Ball 12: Second guide member 12a: Rolling groove 12b: Fitting portion 12c: Tilt restricting portion 13: Screw 14: Base 14a: Fixing portion 14b: Connecting portion 14c: Groove portion 14d: Collision prevention portion 15: First gripping member 15a: First gripping portion 15b: First temporary fixing hole 16: Second gripping member 16a: Second gripping portion 16b: Second temporary fixing hole 17: Torsion spring 18: Output transmission portion 19: Driven body

Claims

1. A vibration type actuator, a driven body driven by the vibration type actuator, and comprising: the vibration type actuator includes an electro-mechanical energy conversion element, and a vibrator having an elastic body to which the electro-mechanical energy conversion element is fixed, a pressing member for pressing the vibrator, a contact body that comes into pressure contact with the vibrator when the pressing member presses the vibrator and relatively moves with respect to the vibrator, and an output unit that outputs a driving force generated when the contact body relatively moves with respect to the vibrator to the driven body, the driven body includes an output transmission unit that grips the output unit with a predetermined spring force in the direction of the relative movement, a vibration wave driving device, wherein when viewed in a cross-section in the direction of the pressing, at the contact surface between the output unit and the output transmission unit, either the output unit or the output transmission unit has a curved surface shape.

2. The output transmission unit includes a first gripping member, a second gripping member different from the first gripping member, and a gripping force applying means for pressing the second gripping member, and the output unit is gripped by the first gripping member and the second gripping member. The vibration wave driving device according to claim 1.

3. When the first temporary fixing hole provided in the first gripping member and the second temporary fixing hole provided in the second gripping member are arranged substantially coaxially, the output transmission unit does not grip the output unit. The vibration wave driving device according to claim 2.

4. A vibration type actuator, a driven body driven by the vibration type actuator, and comprising: the vibration type actuator includes an electro-mechanical energy conversion element, and a vibrator having an elastic body to which the electro-mechanical energy conversion element is fixed, a pressing member for pressing the vibrator, a contact body that comes into pressure contact with the vibrator when the pressing member presses the vibrator and relatively moves with respect to the vibrator, and an output unit that outputs a driving force generated when the contact body relatively moves with respect to the vibrator to the driven body, the driven body includes an output transmission unit that grips the output unit with a predetermined spring force in the direction of the relative movement, the output transmission unit includes a first gripping member, a second gripping member different from the first gripping member, and a gripping force applying means for pressing the second gripping member, and the output unit is gripped by the first gripping member and the second gripping member. When the first temporary fixing hole provided in the first gripping member and the second temporary fixing hole provided in the second gripping member are arranged substantially coaxially, the output transmission portion does not grip the output portion, a vibration wave driving device.

5. When viewed in a cross section along the direction of the relative movement and the direction of the pressing, on the contact surface between the output portion and the output transmission portion, either the output portion or the output transmission portion is curved, the vibration wave driving device according to any one of Claims 1 to 4.

6. When viewed in a cross section along the direction orthogonal to the direction of the relative movement and the direction of the pressing and the direction of the relative movement, the contact portions of the first gripping member and the second gripping member with the output portion are linear, the vibration wave driving device according to any one of Claims 2 to 4.

7. The pressing member, a holding member that holds the vibrator, a guide member that guides the relative movement between the vibrator and the contact body, a biasing member that biases the holding member and the guide member with respect to each other, and includes the vibrator and the contact body are disposed between the holding member and the guide member, the pressing member presses the vibrator by biasing the holding member and the guide member with respect to each other by the biasing member, the vibration wave driving device according to any one of Claims 1 to 6.

8. The vibration wave driving device according to any one of Claims 1 to 7, an imaging element, a control unit that controls the electro-mechanical energy conversion element of the vibration wave driving device, and includes the driven body includes a lens, an imaging device.

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