JP2019187093A - Oscillator and manufacturing method thereof - Google Patents

Abstract

To provide an oscillator, etc. with reduced variation of resonance frequency difference Δf.SOLUTION: An oscillator has: an electromechanical energy conversion device; and a plate-like elastic body to one surface of which the electromechanical energy conversion device is joined, and on the other surface of which a projected part having a parietal part and a sidewall part is provided, in which the side wall part has a thin part with thickness thinner than that of other part of the sidewall part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vibrator having an electro-mechanical energy conversion element, and a plate-like elastic body in which the electro-mechanical energy conversion element is bonded to one surface and a protrusion is provided on the other surface, and It relates to a manufacturing method.

  The vibrator in the vibration type actuator can realize a smooth contact state by providing the contact body in contact with the vibrator to have a spring property. Thereby, the vibration type actuator can obtain good driving performance (see Patent Document 1 below).

  8A and 8B are a perspective view and a perspective sectional view showing a schematic structure of the vibrator 210 in which the protrusion 212 provided on the elastic body 213 has a spring property. The vibrator 210 is elastic at two locations on the elastic body 213, the piezoelectric element 214 bonded to one surface (lower surface in FIG. 8), and the other surface (upper surface in FIG. 8) of the elastic body 213. It is comprised by the protrusion part 212 formed integrally with the body 213. FIG. Each of the two protrusions 212 includes a cylindrical side wall 217, a contact portion (top portion) 218 having a contact surface 218 a with a contact body (not shown in FIG. 8), and the side wall 217 and the contact portion 218. It consists of a connecting part 219 to be connected.

  A step (a difference in height) is provided between the contact part 218 and the connection part 219 so that the contact body does not contact the connection part 219 between the connection part 219 and the contact part 218. Moreover, the connection part 219 can make the contact part 218 have springiness by reducing the rigidity in the push-up direction (Z direction) by making the thickness thinner than the contact part 218.

  In the elastic body 213, a groove 216 is formed at a connection portion with the projection 212. By forming the groove 216 when the elastic body 213 is pressed to integrally mold the protrusion 212, the thickness of the thin portion in this portion is caused to flow to the side wall 217, and the thickness of the side wall 217 is reduced. It is possible to secure rigidity.

  The speed at which the contact body (not shown in FIG. 8) is driven in the feed direction (X direction) depends on the X direction component of the elliptic motion, that is, the vibration amplitude in the X direction in the vibration of mode B, and the Z direction component of the elliptic motion. That is, it does not depend much on the vibration amplitude in the Z direction in the vibration of mode A. The drive of the vibration type actuator brings the speed to the target speed by sweeping the drive frequency from the high frequency side to the low frequency side.

  At this time, if the resonance frequency of mode A is higher than the resonance frequency of mode B, the resonance frequency of mode A exceeds the resonance frequency of mode A before the frequency of mode B reaches the resonance frequency of mode B. The frequency in mode A vibration decreases rapidly. As a result, the vibration type actuator becomes inoperable before the amplitude in the vibration of the mode B related by the speed becomes sufficiently large. Therefore, in a state where the protrusion 212 and the contact body (not shown in FIG. 8) are in pressure contact, the resonance frequency of mode B ≧ the resonance frequency of mode A must be satisfied.

  On the other hand, since the protrusion 212 is disposed near the antinode in the vibration of mode A and in the vicinity of the node in the vibration of mode B, when the pressure is applied, the increase amount of the resonance frequency of mode A is the resonance of mode B. It becomes larger than the increase amount of the frequency. As a result, the resonance frequency difference Δf defined by the resonance frequency of mode B−the resonance frequency of mode A (a value obtained by subtracting the resonance frequency of mode A from the resonance frequency of mode B) becomes small.

  The design of the vibrator is performed by a single vibrator. Specifically, the lengths of the elastic body 213 in the X direction and the Y direction are determined so as to be within a numerical range (allowable range) allowed for Δf in the non-pressurized state. The allowable range is derived from the relationship between Δf in the pressurized state and Δf in the non-pressurized state.

JP 2011-234608 A

  However, if a large number of vibrators 210 as shown in FIG. 8 are produced, Δf varies due to variations in dimensions, and as a result, vibrators 210 that fall outside the allowable range may be generated, leading to a decrease in yield.

  An object of the present invention is to provide a vibrator or the like in which variations in the resonance frequency difference Δf are reduced.

  The vibrator according to the present invention includes an electro-mechanical energy conversion element, a plate in which the electro-mechanical energy conversion element is bonded to one surface, and a protrusion having a top portion and a side wall portion is provided on the other surface. The side wall portion has a thin portion that is thinner than other portions of the side wall portion.

  In addition, the method for manufacturing a vibrator according to the present invention includes an electro-mechanical energy conversion element and a protrusion having the electro-mechanical energy conversion element bonded to one surface and a top portion and a side wall portion on the other surface. A plate-like elastic body provided with a measuring step for measuring a resonance frequency for each vibration mode, and a resonance frequency for each vibration mode measured in the measurement step. A determination step for determining whether to form a thin portion on the side wall portion, and a formation step for forming the thin portion on the side wall portion based on the determination in the determination step. To do.

  According to the vibrator and the method for manufacturing the vibrator according to the present invention, by using the thin-walled portion (side wall portion, protruding portion) as the adjustment portion for adjusting the resonance frequency difference Δf, the decrease in the Q value can be suppressed low. On the other hand, it is possible to provide a vibrator or the like in which variations in the resonance frequency difference Δf are reduced. This is because the protruding portion (side wall portion) is separated from the joint surface between the electromechanical energy conversion element and the elastic body, so that even if a thin wall portion is provided to change (adjust) Δf by processing, -It is because the fall of Q value by the deterioration of the joining state of a mechanical energy conversion element and an elastic body is suppressed low.

5A is a perspective view of the vibrator according to the first embodiment of the present invention, FIG. 5B is a top view thereof, FIG. 5C is a perspective sectional view of the vicinity of the protruding portion, and FIG. It is a figure showing a node in vibration of two vibration modes of a vibrator concerning an embodiment of the present invention. 7 is a top view of a vibrator according to a second embodiment of the invention. FIG. 6 is a top view of a vibrator according to a third embodiment of the invention. FIG. It is a flowchart of the manufacturing method of the vibrator | oscillator which concerns on embodiment of this invention. 1A is a top view and FIG. 1B is a block diagram illustrating a schematic configuration of an imaging apparatus including a vibration type actuator according to an embodiment of the present invention. It is a figure explaining the schematic structure and drive principle of a vibrator and a vibration type actuator having the vibrator. It is (a) perspective view and (b) perspective sectional view which show schematic structure of the vibrator | oscillator which gave the spring property to the projection part.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present embodiment, the vibration type actuator includes a vibrator that excites driving vibration and a contact body that is in pressure contact with the vibrator, and the vibrator and the contact body can be relatively moved by the driving vibration. It shall refer to what has a simple structure. In other words, it means that the drive output of the vibrator can be taken out by relative movement between the vibrator and the contact body.

  The driving principle of the vibration type actuator 100 will be described in detail.

  FIG. 7 is a diagram for explaining the schematic structure and driving principle (vibration mode) of the linear drive type vibration actuator 100. FIG. 7A is a perspective view illustrating a schematic structure of the vibration type actuator 100. FIG. 7B is a top view illustrating a schematic structure of an electromechanical energy conversion element (piezoelectric element) 114 that is a component of the vibration type actuator 100. FIG. 7C is a perspective view for explaining a first vibration mode (hereinafter referred to as “mode A”) excited by the vibrator 115 constituting the vibration type actuator 100. FIG. 7D is a perspective view for explaining a second vibration mode (hereinafter referred to as “mode B”) excited by the vibrator 115 constituting the vibration type actuator 100.

  The vibration type actuator 100 includes a contact body 111 and a vibrator 115. The vibrator 115 is generally composed of a substantially rectangular and plate-like elastic body 113, a piezoelectric element 114 which is a substantially rectangular and plate-like electro-mechanical energy conversion element bonded to one surface of the elastic body 113, and an elastic member. It is composed of two protrusions 112 provided on the other surface of the body 113. The contact body 111 is configured such that the vibrator 115 is in pressure contact. The contact body may be any member that is pressurized from the vibrator and movable relative to the vibrator, and is not limited to a member that directly contacts the vibrator. It may be indirectly in contact.

  In the vibration type actuator 100, a plurality of vibrations in a desired vibration mode are excited in the vibrator 115 by applying a voltage having a specific frequency to the piezoelectric element 114. The vibration for driving the contact body 111 is formed by superimposing the vibrations of the plurality of vibration modes. For example, the contact body 111 is driven by exciting two vibration modes in the vibrator 115.

  As shown in FIG. 7B, for example, electrode regions 114A and 114B that are equally divided in the longitudinal direction are formed in the piezoelectric element 114, and the polarization direction in each electrode region is the same direction (+). is there. Of the electrode regions 114A and 114B of the piezoelectric element 114, the alternating voltage VA is applied to the electrode region 114A, and the alternating voltage VB is applied to the electrode region 114B.

  If the alternating voltages VA and VB are both in the vicinity of the resonance frequency of mode A and are both in-phase alternating voltage, the entire piezoelectric element 114 extends in the polarization direction at a certain moment. At the moment, it shrinks in the polarization direction. As a result, the vibration of mode A (first vibration) shown in FIG.

  Further, if the alternating voltages VA and VB are alternating voltages that are in the vicinity of the resonance frequency of mode B and are 180 ° out of phase with each other, at a certain moment, a part of the piezoelectric element 114 (electrode region 114A). The portion where is formed shrinks in the polarization direction. At the same time, the other part (the part where the electrode region 114B is formed) extends in the polarization direction. At another moment, a part of the piezoelectric element 114 (part where the electrode region 114A is formed) extends in the polarization direction. At the same time, the other part (the part where the electrode region 114B is formed) shrinks in the polarization direction. As a result, vibration of mode B (second vibration) shown in FIG.

  In the vibration type actuator 100, the vibrator 115 is excited by the superimposed vibrations of mode A and mode B. Both mode A and mode B are vibration modes (out-of-plane vibration mode) in the out-of-plane direction of the plate-like vibrator 115. Mode A is a primary out-of-plane vibration mode in which two nodes (where the amplitude is minimized) appear substantially parallel to the long side of the vibrator 115. Mode B is a secondary out-of-plane vibration mode in which three nodes appear approximately parallel to the short side of the vibrator 115.

  The protrusion 112 is arranged in the vicinity of a position that becomes an antinode (where the amplitude becomes maximum) in the vibration of mode A, and in the vicinity of a position that becomes a vibration node in the vibration of mode B. Therefore, the tip surface of the protrusion 112 performs a pendulum motion with the mode B vibration node as a fulcrum, and reciprocates in the X direction, and reciprocates in the Z direction by the mode A vibration.

  Here, the Z direction is the direction in which the vibrator is pressed against the contact body (the direction in which the protrusions expand and contract in vibration of mode A). Further, the X direction is a direction in which the vibrator and the contact body move relative to each other (an antinode direction in mode A vibration). The Y direction is a direction perpendicular to the XZ plane (a plane including the X direction and the Z direction).

  Therefore, the modes A and B are overlapped so that the vibration phase difference of the alternating voltage VA between the modes A and B is in the vicinity of ± π / 2, so that the elliptical motion in the XZ plane is formed on the tip surface of the protrusion 112. Can be generated. In addition, since frictional force due to pressure contact acts between the protrusion 112 and the contact body 111, a driving force (thrust) for driving the contact body 111 in the X direction is generated by the elliptical motion of the protrusion 112. be able to.

<First Embodiment>
An embodiment of a vibration type actuator will be described in detail.

  FIG. 1 is a diagram according to the first embodiment of the present invention, and is a diagram illustrating a structure of a vibrator included in a linear drive type vibration actuator. It should be noted that any of the vibration type actuators each having a vibrator in the following embodiments is driven by the drive principle described above. Therefore, description of the driving principle is omitted below.

  1A and 1B are a perspective view of the vibrator 310 and a top view of the vibrator 310, respectively. As described with reference to FIG. 8, the vibrator 310 includes an elastic body 313 and an electromechanical energy conversion element (piezoelectric element) 314, and a support portion 320 and a fixing portion 321 are provided at both ends of the elastic body 313. .

  The elastic body 313 is provided with a plurality of hollow protrusions 312 (two in FIG. 1). The protrusion 312, the elastic body 313, and the piezoelectric element 314 are collectively referred to as a vibrator main body 315. The cross section of the protrusion 312 (the AA cross section in FIG. 1A) is a top portion having a side wall 317 as shown in FIG. 1C and a contact surface 318a with a contact body (not shown in FIG. 1). (Contact part) 318, a side wall part 317 and a connecting part 319 for connecting the contact part 318.

  The connecting portion 319 is thinner than the contact portion 318, thereby lowering the rigidity in the Z direction and having a predetermined spring property. Therefore, the vibrator 310 and the contact body (not shown in FIG. 1) are in smooth contact. As shown in FIG. 1D, the contact portion may be further drawn to form a top portion (contact portion) 328 having a thickness substantially the same as that of the connecting portion 319.

  The support part 320 is integrally extended from both ends of the elastic body 313, and the fixing part 321 is joined to a fixing member (not shown) by welding or joining. The two holes 322a and 322b are positioning holes for arranging and fixing the vibrator at predetermined positions. The support part 320 is partially reduced in thickness so that the vibration of the elastic body 313 is not transmitted to the fixed part 321 to reduce the rigidity. The support part 320 and the fixing part 321 are collectively referred to as a vibrating body attachment part 322.

  In the present embodiment, a resonator in which Δf (a value obtained by subtracting the resonance frequency of mode A from the resonance frequency of mode B) is adjusted from a value smaller than the allowable range to a value within the allowable range is shown. As a method of performing the adjustment, a method of forming a thin portion 317a (which is a thin portion) on a part of the side wall portion 317 (using the side wall portion as an adjustment portion) is adopted. Since the protruding portion (side wall portion) is separated from the joint surface between the electromechanical energy conversion element and the elastic body, even if a thin portion is provided to change (adjust) Δf by processing, the electromechanical energy A decrease in the Q value due to deterioration of the bonding state between the conversion element and the elastic body can be suppressed to a low level.

  Here, the thin portion 317a as an adjustment portion for adjusting Δf overlaps the antinode in the vibration of mode A. The thin portion 317a is formed by laser processing (by removing a part of the side wall portion 317). At this time, a method other than laser processing may be used as long as the processing can be performed with a predetermined accuracy or higher. The same applies to the second and subsequent embodiments.

  FIG. 2A shows a node in the mode A vibration described in FIG. 7C by a broken line 10a, and an antinode in the mode A vibration by a one-dot chain line 20a. FIG. 2B shows the nodes in the mode B vibration described in FIG. 7D by the broken lines 10b and 11b, and the antinodes in the mode B vibration by the alternate long and short dash line 20b.

  Since the thin portion 317a overlaps the antinode 20a in the vibration of mode A, the tensile stress in the Y direction at the base of the side wall portion 317 (the groove portion 316 formed in the side portion 317) is large. Therefore, by forming the thin wall portion 317a on a part of the side wall portion 317 (with D cut), the drag generated against the tensile stress in the Y direction is weakened. As a result, the resonance frequency of mode A is lowered.

  Further, the thin portion 317a is displaced from the nodes 10b and 11b in the mode B (does not overlap with the nodes 10b and 11b). Further, the thin portion 317a is in the region (in the region B) between the node 11b closest to the free end and the free end in the vibration of mode B. Therefore, the tensile stress in the X direction at the base of the side wall portion 317 (the groove portion 316 formed therein) is small. Therefore, even if the thin portion 317a is formed in a part of the side wall portion 317, the degree to which the drag generated against the tensile stress in the X direction is weakened is small. As a result, the resonance frequency of mode B is not lowered as much as the resonance frequency of mode A described above.

  By such an action, Δf becomes large and can be adjusted to a value within the allowable range.

  The ratio D (thickness of the thin portion / thickness of the portion other than the thin portion in the side wall) of the thickness of the thin portion and the thickness of the side wall portion other than the thin portion is 0.2 ≦ D ≦ 0. 8 is preferred. If the ratio D is less than 0.2, the amount of change in Δf per thickness to be thinned is too large, making it difficult to adjust Δf appropriately. In this case, the problem of insufficient strength becomes obvious. If the ratio D is greater than 0.8, the amount of change in Δf per thinned thickness (processing amount) is too small, and in this case, it is difficult to adjust Δf appropriately.

Second Embodiment
FIG. 3 is a top view of the vibrator 410 according to the second embodiment of the present invention. Note that the overall structure of the vibrator 410 conforms to the overall structure of the vibrator 310 shown in FIG. That is, the vibrator 410 is bonded to the elastic body 413 and one surface (lower surface) of the elastic body 413, the piezoelectric element (not shown in FIG. 3), and the other surface (upper surface) of the elastic body 413. And a protrusion 412 formed integrally with the elastic body 413.

  In the present embodiment, a vibrator in which Δf is adjusted from a value larger than the allowable range to a value within the allowable range is shown. As a method of performing the adjustment, a method of forming a thin portion 417a (which is a thin portion) on a part of the side wall portion 417 is employed. Since the protruding portion (side wall portion) is separated from the joint surface between the electromechanical energy conversion element and the elastic body, even if a thin portion is provided to change (adjust) Δf by processing, the electromechanical energy A decrease in the Q value due to deterioration of the bonding state between the conversion element and the elastic body can be suppressed to a low level.

  Here, the thin portion 417a as an adjustment portion for adjusting Δf overlaps the antinode 20a in the vibration of mode A (see FIG. 2 for 20a).

  Since the thin portion 417a overlaps the antinode 20a in the vibration of mode A, the tensile stress in the Y direction at the base of the side wall portion 417 (the groove portion 416 formed therein) is large. Therefore, by forming the thin portion 417a in a part of the side wall portion 417, the drag generated against the tensile stress in the Y direction is weakened. As a result, the resonance frequency of mode A is lowered.

  Moreover, the thin part 417a is close to the antinode 20b in the vibration of mode B (displaced from the nodes 10b and 11b. It does not overlap the nodes 10b and 11b) (see FIG. 2 for 20b, 10b, and 11b). Further, the thin portion 417a is not in the region (in the region B) between the node 11b closest to the free end and the free end in the vibration of mode B (see FIG. 2 for the region 11b and the region B). ). Therefore, the tensile stress in the X direction at the base of the side wall portion 417 (the groove portion 416 formed therein) is large. Therefore, by forming the thin portion 417a in a part of the side wall portion 417, the drag generated against the tensile stress in the X direction is weakened. As a result, the resonance frequency of mode B decreases.

  Here, in this embodiment, the tensile stress in the X direction due to the vibration in mode B is larger than the tensile stress in the Y direction due to the vibration in mode A. For this reason, the resonance frequency of mode B is much lower than the resonance frequency of mode A.

  By such an action, Δf becomes small and can be adjusted to a value within the allowable range.

<Third Embodiment>
FIG. 4 is a top view of a vibrator 510 according to the third embodiment of the present invention. Note that the overall structure of the vibrator 510 conforms to the overall structure of the vibrator 310 shown in FIG. That is, the vibrator 510 is bonded to the elastic body 513, one surface (lower surface) of the elastic body 513, two locations of the piezoelectric element (not shown in FIG. 4) and the other surface (upper surface) of the elastic body 513. And a protrusion 512 formed integrally with the elastic body 513.

  This embodiment shows a vibrator in which Δf is adjusted from a value smaller than the allowable range to a value within the allowable range. As a method of performing the adjustment, a method of forming a thin portion 517a (which is a thin portion) on a part of the side wall portion 517 is employed. Since the protruding portion (side wall portion) is separated from the joint surface between the electromechanical energy conversion element and the elastic body, even if a thin portion is provided to change (adjust) Δf by processing, the electromechanical energy A decrease in the Q value due to deterioration of the bonding state between the conversion element and the elastic body can be suppressed to a low level.

  Here, the thin portion 517a as an adjustment portion for adjusting Δf overlaps the node 11b in the vibration of mode B (see FIG. 2 for 11b).

  Since the thin part 517a overlaps with the node 11b in the vibration of mode B, the tensile stress in the X direction at the base of the side wall part 517 (the groove part 516 formed therein) is small. Therefore, by forming the thin part 517a in a part of the side wall part 517, the degree to which the drag generated against the tensile stress in the X direction is weakened is small. As a result, the resonance frequency of mode B is not lowered as much as the resonance frequency of mode A described later.

  Further, the thin portion 517a is displaced from the node 10a in the vibration of mode A (does not overlap with the node 10a). Further, the thin portion 517a is not in the region (in the region A) between the node 10a in the vibration of mode A (in the side closest to the free end) and the free end (in FIG. 2). Therefore, the tensile stress in the Y direction at the base of the side wall portion 517 (the groove 516 formed therein) is large. Therefore, by forming the thin portion 517a in a part of the side wall portion 517, the drag generated against the tensile stress in the Y direction is weakened. As a result, the resonance frequency of mode A is lowered. In this embodiment, since the nodes in the mode A vibration are only the nodes 10a, all the nodes in the mode A vibration are the nodes closest to the free end.

  By such an action, Δf becomes large and can be adjusted to a value within the allowable range.

<Fourth embodiment>
FIG. 5 is a flowchart according to the method for manufacturing a vibrator according to the fourth embodiment of the invention. As shown in FIG. 5, first, in the measurement step 61, the resonance frequency for each vibration mode is measured by an impedance analyzer or the like. Next, in the determination step 62, the necessity determination of the resonance frequency adjustment (determination of whether to form a thin portion on the side wall portion) is performed based on the measurement result (resonance frequency for each vibration mode) in the measurement step 61. . Here, the necessity determination is performed based on whether or not the resonance frequency difference Δf is within an allowable range.

  Next, in the determination step 62, when it is determined that the resonance frequency adjustment is necessary (the resonance frequency difference Δf is not within the allowable range), the process proceeds to the adjustment step 63, and when the thin portion is formed, It is determined how much amount (machining amount) of machining is to be performed at which position (machining position). Details of the adjustment process will be described later.

  Next, the resonance frequency is measured again in the measurement step 61, and the necessity determination is performed again in the determination step 62. If it is determined in the determination step 62 that the resonance frequency adjustment is necessary again, the adjustment step 63 is performed again.

  Here, the adjustment process will be described in detail. In the adjustment step 63, it is determined how much amount (machining amount) of machining is to be performed on which position (machining position) on the side wall from the deviation amount of the difference Δf between the two resonance frequencies from the allowable range. The processing position and the processing amount depend on the relationship between the position of the node or the belly and the position of the protrusion in the vibration in the vibration mode, and are limited to the locations shown in the first to third embodiments of the present invention. I don't mean. The processing position and the processing amount may be determined (derived) based on a correspondence table created in advance, or may be determined (calculated) by other methods (for example, a calculation formula). The correspondence table clarifies the correspondence relationship between Δf obtained by simulation and processing / measurement results for an actually created sample, the processing position, and the processing amount.

  In the determination step 62, when it is determined that the resonance frequency adjustment is not possible (resonance frequency difference Δf is within the allowable range), the series of steps is ended.

<Other embodiments>
Although the present invention has been described in detail based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included. For example, the vibrator according to the present invention is not limited to the linear vibration actuator shown in FIG. 7A, but is a rotary vibration actuator or a vibration actuator having multiple degrees of freedom. It can also be applied to.

  Further, the shape of the protrusion 312 or the like included in the vibrator is not limited to a cylindrical shape, and the protrusion may be hollow. Furthermore, the above-described embodiments are merely examples of the present invention, and the embodiments can be appropriately combined.

  Further, the vibration type actuator of the present invention can be used in various applications such as a lens driving application of an image pickup apparatus (optical device), a rotational driving application of a photosensitive drum of a copying machine, and a driving application of a stage. Here, as an example, a vibrator (310) or the like is arranged in an annular shape, and a vibration type actuator that rotationally drives a ring-shaped contact body is arranged in a lens barrel, and a lens (including one or more lenses) is used as an optical member. An imaging device (optical apparatus) used for driving the group will be described. Note that the optical member to be driven may be an imaging element in addition to the lens group.

  FIG. 6A is a top view illustrating a schematic configuration of the imaging apparatus (camera) 700. The imaging device 700 includes a camera main body 730 on which an imaging element 710 and a power button 720 are mounted. Further, the imaging apparatus 700 includes a lens barrel 740 including a first lens group (not shown), a second lens group 820, a third lens group (not shown), a fourth lens group 840, and vibration type actuators 620 and 640. Prepare. The lens barrel 740 is detachable from the camera body 730 as an interchangeable lens.

  In the imaging apparatus 700, the second lens group 820 is driven by the vibration type actuator (vibration type driving device) 620, and the fourth lens group 840 is driven by the vibration type actuator 640. As the vibration type actuators 620 and 640, the vibrator described with reference to FIGS. 1 to 5 is used. For example, the rotation of the contact body constituting the vibration type actuator 620 is converted into a linear movement in the optical axis direction by a gear or the like, and the position of the second lens group 820 in the optical axis direction is adjusted. The vibration type actuator 640 can have the same configuration.

  FIG. 6B is a block diagram illustrating a schematic configuration of the imaging apparatus 700. The first lens group 810, the second lens group 820, the third lens group 830, the fourth lens group 840, and the light amount adjustment unit (aperture) 850 are arranged at predetermined positions on the optical axis inside the lens barrel 740. The light that has passed through the first lens group 810 to the fourth lens group 840 and the light amount adjustment unit 850 forms an image on the image sensor 710. The image sensor 710 converts the optical image into an electrical signal and outputs the electrical signal, and the output is sent to the camera processing circuit 750.

  The camera processing circuit 750 performs amplification, gamma correction, and the like on the output signal from the image sensor 710. The camera processing circuit 750 is connected to the CPU 790 through the AE gate 755 and is connected to the CPU 790 through the AF gate 760 and the AF signal processing circuit 765. The video signal that has undergone 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. The AF signal processing circuit 765 extracts a high frequency component of the video signal, generates an evaluation value signal for autofocus (AF), and supplies the generated evaluation value to the CPU 790.

  The CPU 790 is a control circuit that controls the overall operation of the imaging apparatus 700, and generates a control signal for determining exposure and focusing from the acquired video signal. The CPU 790 controls the driving of the vibration type actuators 620 and 640 and the meter 630 so that the determined exposure and an appropriate focus state can be obtained, and thereby the second lens group 820, the fourth lens group 840, and the light amount adjustment unit 850. Adjust the position in the optical axis direction. Under the control of the CPU 790, the vibration type actuator 620 moves the second lens group 820 in the optical axis direction, the vibration type actuator 640 moves the fourth lens group 840 in the optical axis direction, and the light amount adjustment unit 850 is controlled by the meter 630. Drive controlled.

  The position in the optical axis direction of the second lens group 820 driven by the vibration type actuator 620 is detected by the first linear encoder 770, and the detection result is notified to the CPU 790, which is fed back to the drive of the vibration type actuator 620. Similarly, the position of the fourth lens group 840 driven by the vibration type actuator 640 in the optical axis direction is detected by the second linear encoder 775, and the detection result is notified to the CPU 790, which is fed back to the drive of the vibration type actuator 640. Is done. The position in the optical axis direction of the light amount adjustment unit 850 is detected by the diaphragm encoder 780, and the detection result is notified to the CPU 790, which is fed back to the drive of the meter 630.

  Note that the vibration type actuators 620 and 640 are not limited to applications in which the lens group is driven (movable) in the optical axis direction in the imaging apparatus. In order to correct image blur, it can also be used for applications such as driving an image blur correction lens or an image sensor in a direction orthogonal to the optical axis.

210, 310, 410, 510 Vibrator 214, 314 Electro-mechanical energy conversion element (piezoelectric element)
213, 313, 413, 513 Elastic body 212, 312, 412, 512 Protruding part 217, 317, 417, 517 Side wall part 317a, 417a, 517a Thin part

Claims (13)

An electro-mechanical energy conversion element; and a plate-like elastic body in which the electro-mechanical energy conversion element is bonded to one surface and a protrusion having a top and a side wall is provided on the other surface. A vibrator,
The vibrator according to claim 1, wherein the side wall portion has a thin wall portion that is thinner than other portions of the side wall portion.   The vibrator according to claim 1, wherein the thin portion overlaps an antinode in vibration of a first vibration mode that is a vibration mode excited by the vibrator.   The thin-walled portion does not overlap a node in the vibration of the second vibration mode different from the first vibration mode, and a node closest to the free end in the vibration of the second vibration mode The vibrator according to claim 2, wherein the vibrator is in a region between the free ends.   The vibrator according to claim 1, wherein the thin portion overlaps a node in vibration of a second vibration mode different from the first vibration mode.   The thin portion does not overlap with a node in the vibration of the first vibration mode, and in a region between the node closest to the free end and the free end in the vibration of the first vibration mode. The vibrator according to claim 4, wherein the vibrator is not provided.   6. The vibration according to claim 1, wherein the elastic body is provided with a plurality of protrusions in an antinode direction in the vibration of the first vibration mode. Child. The elastic body is provided with a plurality of protrusions in the antinode direction in the vibration of the first vibration mode,
The thin-walled portion does not overlap a node in the vibration of the second vibration mode different from the first vibration mode, and a node closest to the free end in the vibration of the second vibration mode The vibrator according to claim 2, wherein the vibrator is not in a region between the free ends. The vibrator according to any one of claims 1 to 7,
A contact body pressed from the protrusion,
A vibratory actuator, wherein the vibrator and the contact body are relatively movable by a plurality of vibration modes excited by the vibrator. The vibration type actuator according to claim 8,
And an optical member movable by the vibration actuator.   The optical member according to claim 9 is a lens group including one or more lenses.   The optical member according to claim 9 is an imaging device. An electro-mechanical energy conversion element; and a plate-like elastic body in which the electro-mechanical energy conversion element is bonded to one surface and a protrusion having a top and a side wall is provided on the other surface. A method of manufacturing a vibrator,
A measurement process for measuring the resonance frequency for each vibration mode;
A determination step of determining whether to form a thin portion on the side wall portion based on the resonance frequency for each vibration mode measured in the measurement step;
And a forming step of forming the thin portion on the side wall portion based on the determination of the determination step.   13. The method for manufacturing a vibrator according to claim 12, wherein the measurement step, the determination step, and the formation step are repeated until it is determined in the determination step that the thin portion is not formed.

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