JP2016032351A - Vibration type actuator, optical equipment, and imaging apparatus - Google Patents

Abstract

An object of the present invention is to reduce the size of a vibration type actuator by shortening the dimension in the traveling direction. A diaphragm 1 of a vibration type actuator has a plurality of protrusions 1b1-4 provided on a rectangular flat plate portion 1a. When an AC voltage is applied to the piezoelectric element 2 fixed to the diaphragm 1, it vibrates at a high frequency. The friction member in contact with the diaphragm 1 moves relative to the diaphragm 1 due to high-frequency vibration. The protrusions 1b1 to 4 are located at the respective vertices of the rectangle on the flat plate portion 1a. The first set of protrusions 1b1 and 1b2 located diagonally on the flat plate portion 1a have a frictional force relative to the friction member relative to that of the second set of protrusions 1b3 and 1b4 located differently. Big. The first set of protrusions 1b1 and 1b2 have a height relative to the flat plate portion 1a that is higher than the second set of protrusions 1b3 and 1b4, and the tip ends 1d1 and 1b2 of the protrusion 1b1. Part 1d2 contacts the friction member. The diaphragm 1 moves relative to the friction member in the short side direction of the flat plate portion 1a. [Selection] Figure 1

Description

  The present invention relates to a vibration type actuator, and more particularly to a linear drive type vibration wave motor having a plate-like elastic body.

  Ultrasonic motors characterized by small size, light weight, high-speed driving, and silent driving are employed in lens barrels and the like of imaging devices. An ultrasonic motor for linear drive disclosed in Patent Document 1 includes a diaphragm having a rectangular flat plate portion and a protrusion provided on the flat plate portion, a piezoelectric element that is fixed to the vibration plate and vibrates at high frequency, and The friction member is in contact with the protrusion. The diaphragm is excited by a first-order natural vibration mode of bending vibration in the short-side direction and a second-order natural vibration mode of bending vibration in the long-side direction by the high-frequency vibration of the piezoelectric element. Of the two natural vibration modes, in the primary natural vibration mode of the bending vibration in the short side direction, the tip of the protrusion vibrates in the direction perpendicular to the flat plate portion, and the secondary natural vibration mode of the bending vibration in the long side direction. Then, the tip of the protrusion vibrates in the horizontal direction with respect to the flat plate portion. By combining these natural vibration modes, an elliptical motion is generated at the protrusions of the diaphragm. The protrusions of the diaphragm are pressed against and contact the friction member, and the diaphragm and the friction member relatively move in the long side direction due to the friction generated by the elliptical motion.

Japanese Patent Laid-Open No. 2004-304877

In recent years, there has been an increasing demand for downsizing electronic devices equipped with ultrasonic motors, in particular, driving devices for optical elements such as lenses. Since the ultrasonic motor disclosed in Patent Document 1 is configured to travel in the long side direction of the rectangular diaphragm, the size in the traveling direction is large. For this reason, there existed a problem that the size of the whole drive device using an ultrasonic motor will become large.
An object of the present invention is to reduce the size of the vibration actuator by reducing the dimension in the traveling direction.

  In order to solve the above-described problems, a vibration type actuator according to the present invention includes a vibration plate having a plurality of protrusions provided on a rectangular flat plate portion, a piezoelectric element fixed to the vibration plate, and the vibration. And a friction member that moves relatively in contact with the protrusion of the diaphragm by vibration of the board. The first set of protrusions positioned on the first diagonal line in the flat plate portion is more frictional than the second set of protrusion portions positioned on the second diagonal line in the flat plate portion. The frictional force is relatively large.

  According to the present invention, the size of the vibration type actuator can be reduced by shortening the dimension in the traveling direction.

It is explanatory drawing of the structural example of the ultrasonic motor which concerns on 1st Embodiment of this invention. It is a figure explaining the vibration state of the ultrasonic motor of FIG. It is a perspective view explaining the elliptical motion which generate | occur | produces in the diaphragm of 1st Embodiment. It is a figure explaining a linear drive device as an example of application of a 1st embodiment. It is a figure explaining the lens drive device using the linear drive device of FIG. It is explanatory drawing of the structural example of the ultrasonic motor which concerns on 2nd Embodiment of this invention. It is a figure explaining the vibration state of the ultrasonic motor of FIG.

  The vibration type actuator according to each embodiment of the present invention will be described in detail with reference to the accompanying drawings. The vibration type actuator according to each embodiment can be applied to an electronic device that is required to be small and light and have a wide driving speed range. For example, application to a driving device for an optical element such as a lens or a prism, an optical device such as a lens barrel, an imaging device, or the like is applicable.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram illustrating a basic configuration of the ultrasonic motor according to the present embodiment. 1A is a plan view and FIG. 1B is a front view. 1C and 1D are side views when viewed from opposite directions. 1E is a bottom view, and FIG. 1F is a rear view. In this specification, a direction parallel to the long side direction of the diaphragm of the ultrasonic motor is defined as the X direction, and a direction parallel to the short side direction of the diaphragm is defined as the Y direction. A direction orthogonal to the X direction and the Y direction, that is, a direction parallel to the thickness direction of the diaphragm is defined as a Z direction. In the Z direction, the direction from the diaphragm to the friction member (see FIG. 4: friction member 3) is defined as the + Z direction, and the direction from the friction member to the diaphragm is defined as the −Z direction.

  The ultrasonic motor 10 includes a diaphragm 1 and a piezoelectric element 2. The diaphragm 1 includes a rectangular flat plate portion 1a and protrusions 1b1, 1b2, 1b3, 1b4 protruding from the flat plate portion 1a in the + Z direction. The protrusions 1b1, 1b2, 1b3, and 1b4 have cylindrical body portions 1c1, 1c2, 1c3, and 1c4, respectively. Tip portions 1d1, 1d2, 1d3, and 1d4 are provided on the body portions 1c1, 1c2, 1c3, and 1c4, respectively. These tip portions are columnar portions having a diameter smaller than that of the body portion, and contact with a friction member described later to generate friction. The protrusions 1b1, 1b2, 1b3, and 1b4 are formed by integral molding with the flat plate portion 1a by drawing or the like, or are attached to the flat plate portion 1a by bonding or the like as separate parts. In FIGS. 1B and 1F, the lengths of the protrusions 1b1, 1b2, 1b3, and 1b4 in the Z direction are indicated by h1, h2, h3, and h4, respectively.

  The piezoelectric element 2 is fixed to the diaphragm 1 and performs high frequency vibration. The piezoelectric element 2 has a first region 2a (left region in FIG. 1A) and a second region 2b (right region in FIG. 1A) divided into two by a center line Yc parallel to the Y direction. Each region 2a, 2b is polarized in the same direction. For example, the first region 2a is assigned to the A phase, and the second region 2b is assigned to the B phase. The third region 2c located between the first region 2a and the second region 2b is not polarized. In the third region 2c, an electrode is formed which is used as a ground that is conducted from the electrode formed over the entire back surface 2e of the piezoelectric element 2 via the electrode formed in the side surface region 2d. The connecting portions 1e and 1f are U-shaped when viewed from the Z direction, and are portions protruding from the flat plate portion 1a in the X direction. The connecting portions 1e and 1f are portions that are directly or indirectly connected to a later-described vibrator holding member (see FIG. 4: vibrator holding member 4) that moves in synchronization with the diaphragm 1. The diaphragm 1 is provided on the short side of the rectangular surface. The connecting portions 1e and 1f are provided at positions where there is little displacement in the vibration of the vibration plate 1 and the piezoelectric element 2, and the rigidity is sufficiently weak so that the vibration is not easily hindered. Accordingly, the connecting portions 1 e and 1 f hardly affect the vibration of the diaphragm 1 and the piezoelectric element 2.

  Due to the high-frequency vibration of the piezoelectric element 2, the plate portion 1 a has a primary natural vibration mode related to bending vibration in the short side direction (Y direction) of the diaphragm 1 and bending in the long side direction (X direction) of the diaphragm 1. A secondary natural vibration mode related to vibration is excited. As shown in FIG. 1E, the protrusions 1b1, 1b2, 1b3, 1b4 are in the vicinity of the nodes (X1, X2) of the primary natural vibration mode relating to the bending vibration in the short side direction, and the long sides It is located in the vicinity of the antinodes (Y1, Y2) of the secondary natural vibration mode related to the bending vibration in the direction. A power supply unit (not shown) applies an AC voltage in which the phase difference is changed from + 90 ° to + 270 ° to the first region 2a of the A phase and the second region 2b of the B phase. Thereby, high frequency vibration can be generated in the piezoelectric element 2.

  Next, with reference to FIG. 2, the state of vibration when an AC voltage is applied by delaying the phase of the B phase by about 90 ° with respect to the A phase will be described. FIG. 2A illustrates an AC voltage waveform applied to the A phase and the B phase of the piezoelectric element. The horizontal axis T is a time axis, the vertical axis V is a voltage axis, and the graph shows the voltage change of each phase. Voltage application timing (time) is indicated by phases P1 to P4, respectively. FIGS. 2B, 2C, and 2D correspond to FIGS. 1B, 1C, and 1D, respectively, and schematically show the vibration state in an exaggerated manner. The vibration state at the time corresponding to the phases p1 to p4 having a predetermined delay with respect to the phases P1 to P4 of the AC voltage shown in FIG. FIG. 2C shows a vibration state when viewed from the X direction, and FIG. 2D shows a vibration state when viewed from the opposite side to FIG. 2C in the X direction. Of the body parts 1c1, 1c2, 1c3, and 1c4, FIG. 2C shows the body parts 1c1 and 1c3, and FIG. 2D shows the body parts 1c2 and 1c4. FIG. 2B shows a vibration state when viewed from the Y direction, and illustrates the body parts 1c2 and 1c3 among the body parts 1c1, 1c2, 1c3, and 1c4. In FIG. 2, the piezoelectric element 2, the tip portions 1d1, 1d2, 1d3, and 1d4, and the connecting portions 1e and 1f are omitted for simplification.

In the phases P1 and P3 shown in FIG. 2A, the direction of the voltage is different between the A phase and the B phase, and they have different signs. Moreover, in the phases P2 and P4, the direction of the voltage is the same in the A phase and the B phase, and is the same sign.
At the time corresponding to the phases P2 and P4, voltages having the same sign are applied to the A phase and the B phase. Therefore, the primary natural vibration mode related to the bending vibration in the short side direction is excited. As shown by an arrow with 2 in the round frame in FIG. 2C, the amplitude in the Y direction of each tip of the body portions 1c1, 1c2, 1c3, 1c4 is maximized. In addition, at the time corresponding to the phases P1 and P3, voltages having different signs are applied to the A phase and the B phase, and in this case, the regions of the A phase and the B phase expand and contract in the opposite directions. Therefore, the secondary natural vibration mode related to the bending vibration in the long side direction is excited. The amplitude in the Z direction of each tip of the body portions 1c1, 1c2, 1c3, and 1c4 is maximized as indicated by an arrow indicated by 1 in a round frame in FIG. As a result of applying an AC voltage by delaying the phase of the B phase by about 90 ° with respect to the A phase, the tips of the body portions 1c1, 1c2, 1c3, 1c4 are indicated by arrows in the clockwise direction and the counterclockwise direction, respectively. Elliptic motion occurs.

  FIG. 3 is a perspective view when the diaphragm 1 is viewed from the + Z direction side, and the elliptical motion generated at the tips of the protrusions 1b1, 1b2, 1b3, 1b4 is indicated by arrows. When an AC voltage is applied by delaying the phase of the B phase by about 90 ° with respect to the A phase, the illustrated elliptical motion occurs at the tips of the protrusions 1b1, 1b2, 1b3, 1b4. As a result, the tip portions 1d1, 1d2, 1d3, and 1d4 of the protrusions 1b1, 1b2, 1b3, and 1b4 also perform the same elliptical motion. In this case, the tip portions 1d1 and 1d2 perform an elliptical motion indicated by solid arrows in the −Y direction. Further, the tip portions 1d3 and 1d4 perform an elliptical motion indicated by a dashed arrow with respect to the + Y direction.

The diaphragm 1 is in pressure contact with the friction member. Each of the four protrusions 1b1, 1b2, 1b3, 1b4 is positioned at each vertex of a substantially rectangular frame on the flat plate portion 1a, and is positioned symmetrically with respect to the center line Yc shown in FIG. doing. The tip portions 1d1, 1d2, 1d3, and 1d4 disposed on the body portions 1c1, 1c2, 1c3, and 1c4 have heights h1, h2, h3, and h4 when the flat plate portion 1a is used as a reference. The height of one set of tip portions 1d1 and 1d2 located on the diagonal line on the flat plate portion 1a is larger than the height of another set of tip portions 1d3 and 1d4 located on different diagonal lines. That is, the height relationship of the protrusions 1b1, 1b2, 1b3, 1b4 is as shown in the following equation.
h1> h3, h1> h4, h2> h3, h2> h4 (Formula 1)
h1≈h2, h3≈h4 (Formula 2)

Thus, the height of the pair of protrusions 1b1 and 1b2 is higher than the pair of protrusions 1b3 and 1b4 in the + Z direction. Therefore, the protrusions 1b1 and 1b2 are in contact with a friction member described later, but the protrusions 1b3 and 1b4 are not in contact. Here, the vertical drag applied to the protrusions 1b1, 1b2, 1b3, and 1b4 is N1, N2, N3, and N4, respectively. When the diaphragm 1 is pressurized with the applied pressure F against the friction member, the vertical drag N1, N2 is
N1 = N2 = F / 2 (Formula 3)
It becomes. On the other hand, since the protrusions 1b3 and 1b4 do not contact the friction member, the vertical drag N3 and N4 are
N3 = N4 = 0 (Formula 4)
It becomes.

If the frictional forces between the tip portions of the protrusions 1b1, 1b2, 1b3, and 1b4 and the friction member are f1, f2, f3, and f4, respectively, the following equation is obtained.
f1 = μ × N1 = μ × F / 2, f2 = μ × N2 = μ × F / 2 (Formula 5)
f3 = μ × N3 = 0, f4 = μ × N4 = 0 (Formula 6)
Μ in the equation is a friction coefficient between the diaphragm 1 and the friction member. Therefore, the relationship between the frictional forces f1, f2, f3, f4 is
f1> f3, f1> f4, f2> f3, f2> f4 (Formula 7)
f1≈f2, f3≈f4 (Formula 8)
It becomes.

  Of the four protrusions, the first set of protrusions 1b1 and 1b2 located on the first diagonal in the flat plate part 1a is the second set of protrusions 1b3 and 1b4 located on the second diagonal. It is higher than the pair. Therefore, the first group has a relatively large frictional force with the friction member as compared with the second group. Since the tip portions 1d1 and 1d2 are in contact with the friction member, the vibration plate 1 obtains a propulsive force by the friction between the friction member and the tip portions 1d1 and 1d2 along with the elliptical motion of the protrusions 1b1 and 1b2. Move relative to the + Y direction. In addition, when an AC voltage is applied by delaying the phase of the B phase by about 270 ° with respect to the A phase, elliptical motion in the direction opposite to that in FIG. 2 occurs. In this case, with the elliptical motion of the protrusions 1b1 and 1b2, the diaphragm 1 obtains a propulsive force due to the friction between the friction member and the tip portions 1d1 and 1d2, and moves relative to the −Y direction.

  In the present embodiment, the protrusions 1b1 to 1b4 on the flat plate portion 1a are closer to the belly than the nodes of the second natural vibration mode related to the bending vibration in the long side direction, and the primary related to the bending vibration in the short side direction. It is arranged at a position closer to the node than the antinode of the natural vibration mode. The pair of protrusions 1b1 and 1b2 performs elliptical motion by high-frequency vibration, and the diaphragm 1 can move relative to the friction member in contact with these in the short side direction (Y direction) of the flat plate portion 1a. According to the present embodiment, the size of the vibration type actuator in the traveling direction can be shortened, and downsizing can be realized.

[Application example]
Next, an application example of the ultrasonic motor of the present embodiment will be described with reference to FIGS. 4 and 5.
FIG. 4 is a schematic diagram illustrating a configuration example of the linear drive device 20 using the ultrasonic motor 10. FIG. 4A is a view when seen from the traveling direction of the ultrasonic motor 10. FIG. 4B is a cross-sectional view taken along the line AA in FIG.

  The ultrasonic motor 10 has a diaphragm 1 and a piezoelectric element 2. The friction member 3 contacts the protrusions 1b1 and 1b2 and moves relative to the diaphragm 1 by high-frequency vibration. The diaphragm 1 can move relative to the friction member 3 in the Y direction. The vibrator holding member 4 moves in synchronization with the diaphragm 1. The vibrator holding member 4 supports the diaphragm 1 by the connecting portions 1e and 1f by a plurality of support portions 4a. A plurality of rollers 41 that rotate and slide are disposed on the back surface of the friction member 3, that is, the surface that does not contact the protrusions 1 b 1 and 1 b 2 (surface in the + Z direction). The plurality of support portions 4b rotatably support the rollers 41. The roller 41 is provided to reduce the sliding resistance when the friction member 3 is driven. A mechanism using a rolling roller may be used.

  The pressure spring 42 has a function of bringing the protrusions 1b1 and 1b2 into contact with the friction member 3 in a pressure contact state. The pressurizing spring 42 has a lower end 4 c (an end in the + Z direction) in contact with the piezoelectric element 2 and an upper end in contact with the vibrator holding member 4. Due to the pressure applied by the pressure spring 42, the protrusions 1 b 1 and 1 b 2 are brought into pressure contact with the friction member 3. The vibrator holding member 4 obtains a propulsive force in the Y direction by the driving force generated by the elliptical motion indicated by the arrow in FIG. 2, and can move relatively in the + Y direction.

  In this application example, the ultrasonic motor 10 can travel in the short side direction. That is, the linear drive device 20 can be reduced in size by shortening the dimension of the ultrasonic motor 10 in the traveling direction.

  Next, an application example to the lens driving device will be described with reference to FIG. FIG. 5 is a schematic diagram showing a lens driving unit in a lens driving device equipped with the linear driving device 20 of FIG. In FIG. 5, the direction parallel to the optical axis (optical axis direction) is set as the Y direction. FIG. 5A is a front view when viewed from the optical axis direction. 5B and 5C are side views showing a part of the frame cut away. FIG. 5C shows a lens driving device that is further miniaturized with respect to FIG.

  A cylindrical frame 51 has a lens 52 and a lens holder 53 disposed therein. The lens holder 53 is guided in the optical axis direction (Y direction) along the pair of guide shafts 54 and 55. In the linear drive device 20 shown in FIGS. 5B and 5C, illustrations other than the flat plate portion 1 a of the diaphragm 1, the body portions 1 c 1, 1 c 2, 1 c 3, 1 c 4 and the friction member 3 are omitted.

  The friction member 3 is attached and fixed to a frame 51 that is a fixing member. The diaphragm 1 moves along the friction member 3 fixed to the frame 51, and the vibrator holding member 4 moves in synchronization therewith. The vibrator holding member 4 is provided with a drive transmission unit 43. The lens holder 53 is a driven body connected to the vibrator holding member 4 by the drive transmission unit 43 and moves in the optical axis direction in synchronization with the vibrator holding member 4.

  The linear drive device 20 is driven in accordance with a movement command from a control unit using a CPU (Central Processing Unit). As the vibrator holding member 4 moves in the Y direction in FIG. 5, for example, the lens holder 53 moves in a range (see L4) from the first position indicated by the solid line to the second position indicated by the two-dot chain line. In the lens driving device, the short side direction of the flat plate portion 1 a of the diaphragm 1 is set as the driving direction of the lens holder 53. L2 represents the dimension in the short side direction (Y direction) of the flat plate portion 1a, and the sum of L2 and L3 is L4. L1 represents the dimension of the long side direction (X direction) of the flat plate part 1a. Since the dimension L2 is smaller than the dimension L1, the ultrasonic motor of the present embodiment that uses the short side direction of the flat plate portion 1a as the driving direction is compared with the conventional ultrasonic motor that uses the long side direction as the driving direction. Thus, it is possible to reduce the size in the traveling direction.

  L3 is a distance that allows the lens 52 to move in the lens driving device. That is, L3 is a distance obtained by subtracting L2 that is the dimension in the traveling direction of the ultrasonic motor 10 (dimension in the short side direction) from the moving distance L4 of the linear driving apparatus 20 in the lens driving apparatus. In the case of the miniaturized lens driving device shown in FIG. 5C, the moving distance L4 of the linear driving device 20 is further shortened to a limited length. By shortening the dimension L2 in the traveling direction of the ultrasonic motor 10, the distance L3 that the lens 52 can move can be sufficiently secured. Therefore, the ultrasonic motor 10 of this embodiment can be applied even to a miniaturized lens driving device.

  According to this application example, the size of the lens driving device can be reduced by reducing the dimension of the ultrasonic motor in the traveling direction. In this embodiment, the configuration example in which only the tip portions of the projections 1b1, 1b2 are in contact with the friction member 3 is shown. The member 3 may be in contact. In the present embodiment, the height h1 of the protrusion 1b1 and the height h2 of the protrusion 1b2 are larger than the height h3 of the protrusion 1b3 and the height h4 of the protrusion 1b4, and the protrusions 1b1 and 1b2 are friction members. The example which contacts 3 was shown. On the other hand, even when all of the four projecting portions 1b1, 1b2, 1b3, and 1b4 are in contact with the friction member 3, the relationship expressed by the above formulas 7 and 8 may be satisfied. With this setting, the driving force is reduced, but the same effect as in this embodiment can be obtained.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. In 1st Embodiment, although the example which has arrange | positioned four protrusion parts (leg part) on the flat plate part 1a of the diaphragm 1 in the rectangular shape was shown, in this embodiment, two protrusion parts are provided on the flat plate part 1a. The arranged configuration will be described. In the present embodiment, the same components as those in the first embodiment will be omitted by using a reference numeral obtained by adding 100 to the already used reference numeral.

  FIG. 6 is a diagram illustrating a basic configuration of the ultrasonic motor 110 according to the present embodiment. FIG. 6A is a plan view when viewed from the Z direction, and FIG. 6B is a front view when viewed from the Y direction. 6C and 6D are side views when viewed from opposite directions in the X direction. FIG. 6E is a bottom view.

  As shown in FIG. 6E, the protrusions 101b1 and 101b2 are in the vicinity of the nodes (X1, X2) of the primary natural vibration mode related to the bending vibration in the short side direction and are bent in the long side direction. It is provided in the vicinity of the antinode (Y1, Y2) of the secondary natural vibration mode related to vibration. The protrusions 101b1 and 101b2 are arranged diagonally on the flat plate portion 1a.

  FIG. 7 shows a state of vibration when an AC voltage is applied to the piezoelectric element 102 with the phase of the B phase delayed by about 90 ° with respect to the A phase. The meanings of the drawings shown in FIGS. 7A to 7D are the same as those in FIG. When an AC voltage is applied by delaying the phase of the B phase by about 90 ° with respect to the A phase, elliptical motion is generated in the protrusions 101b1 and 101b2 as indicated by arrows in FIG. Accordingly, the diaphragm 101 moves relatively in the + Y direction.

  In general, in an ultrasonic motor, a driving force is obtained by friction between a protrusion and a friction member. Therefore, when the ultrasonic motor has a plurality of protrusions, the driving efficiency is maximized in an ideal state where the elliptical locus drawn by the tips of the plurality of protrusions is uniform. In the case of a flat plate having a uniform thickness, the rigidity of the flat plate is constant regardless of the location. On the other hand, when the protrusion is disposed on the flat plate, the rigidity is higher in the vicinity of the protrusion than the other portions on the flat plate. For this reason, in the case of the ultrasonic motor 110 having two protrusions, the rigidity is higher in the vicinity of the protrusions 101b1 and 101b2 provided on the diaphragm 101 than in the other parts. In the case of the ultrasonic motor 110, the protrusions 101b1 and 101b2 are diagonally located on the flat plate portion 101a, and are arranged asymmetrically with respect to the center line Yc in FIG. That is, the body portions 101c1 and 101c2 that contribute to rigidity are not plane-symmetric with respect to the YZ plane passing through the center line Yc in the drawing. Therefore, the rigidity distribution of the diaphragm 101 is asymmetric because the positions of the protrusions are not symmetrical. Accordingly, the locus of elliptical motion at the tips of the two protrusions 101b1 and 101b2 is not uniform, and the driving efficiency is reduced. In the ultrasonic motor 10 of the first embodiment, as shown in FIG. 1E, the four protrusions 1b1, 1b2, 1b3, 1b4 are arranged symmetrically with respect to the center line Yc. That is, the body portions 1c1, 1c2, 1c3, and 1c4 that contribute to rigidity are plane-symmetric with respect to the YZ plane that passes through the center line Yc. For this reason, the rigidity distribution of the diaphragm 1 is symmetric, and the loci of the elliptical motion of the two protrusions 1b1 and 1b2 are uniform, so that the driving efficiency does not decrease.

  In the present embodiment, even when the two protrusions are not line-symmetrically arranged in the flat plate portion 101a, relative movement is possible in the short side direction of the flat plate portion 101a, and the size in the traveling direction can be reduced. In comparison with the first embodiment, the driving efficiency is low, but the configuration is simple because the number of protrusions (legs) is small.

In the above-described embodiment, the configuration example in which the diaphragm moves with respect to the fixed friction member has been described. Not limited to this, even if the friction member moves relative to the fixed diaphragm, the effect of downsizing is reduced, but the same effect can be obtained.
As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 1,101 Diaphragm 1a, 101a Flat plate part 1b1-4, 101b1-4 Projection part 2,102 Piezoelectric element 3,103 Friction member

Claims (12)

A diaphragm having a plurality of protrusions provided on a rectangular flat plate portion;
A piezoelectric element fixed to the diaphragm;
A friction member that moves relatively in contact with the protrusion of the diaphragm by vibration of the diaphragm,
The first set of protrusions positioned on the first diagonal line in the flat plate portion is more frictional than the second set of protrusion portions positioned on the second diagonal line in the flat plate portion. A vibration-type actuator characterized by relatively high frictional force with the actuator.   The position of the protrusion in the flat plate portion is closer to the antinode than the node of the secondary natural vibration mode related to the bending vibration in the long side direction of the flat plate portion, and the bending vibration in the short side direction of the flat plate portion. 2. The vibration type actuator according to claim 1, wherein the vibration type actuator is closer to a node than an antinode of the primary natural vibration mode.   3. The vibration type actuator according to claim 1, wherein a height of the protruding portion with respect to the flat plate portion is larger in the first set than in the second set. 4.   4. The vibration type actuator according to claim 1, wherein the vibration plate moves relative to the friction member in a short side direction of the flat plate portion. 5.   5. The vibration type actuator according to claim 1, wherein the plurality of protrusions are positioned at respective vertices of a rectangle in the flat plate portion.   5. The vibration type actuator according to claim 1, wherein the plurality of protrusions are two protrusions positioned diagonally in the flat plate portion. The piezoelectric element has a first region and a second region divided in the long side direction,
7. The vibration type actuator according to claim 1, wherein an alternating voltage having a different phase is applied to the first region and the second region by the driving unit.   The said protrusion part has a trunk | drum part and the front-end | tip part which contacts the said friction member, The said front-end | tip part is a shape part of a smaller diameter than the said trunk | drum part, The any one of Claim 1 to 7 characterized by the above-mentioned. The vibration type actuator according to claim 1. The vibration type actuator according to any one of claims 1 to 8, comprising:
An optical device in which an optical element is moved by moving the diaphragm and the piezoelectric element with respect to the friction member attached to a fixed member. The vibration type actuator according to any one of claims 1 to 8, comprising:
An optical device in which an optical element is moved by moving the friction member with respect to the diaphragm attached to a fixed member.   The optical apparatus according to claim 9 or 10, wherein a short side direction of the flat plate portion is a direction parallel to an optical axis of the optical element. The vibration type actuator according to any one of claims 1 to 8, comprising:
An imaging device, wherein an optical element is moved by moving the diaphragm relative to the friction member.

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