JP2014150713A - Linear drive unit, camera device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear drive unit in which generation of noise can be suppressed sufficiently in the audible area, by achieving slow stop where the stop position of a lens support is stable.SOLUTION: A linear drive unit includes a drive shaft 20 coupled with a vibration member 18 having a piezoelectric element 14 telescoping by a drive voltage of repetitive waveform and vibrating together with the vibration member 18, a lens support 26 friction coupled with the drive shaft 20 movably in the axial direction thereof by vibration of the drive shaft 20, and a position sensor 28 for detecting the axial position of the lens support 26. The drive voltage is controlled depending on the axial direction of the lens support 26, and the linear drive unit is controlled by the waveform so that the travel speed when the lens support 26 moves from a movement start position toward a first predetermined position and arrives at the first predetermined position is larger than the travel speed when the lens support 26 arrives at a target stop position in the above-mentioned direction from the first predetermined position, and the lens support 26 stops movement upon arrival at the target stop position.

Description

  The present invention relates to a linear drive device used for a camera or a digital camera mounted on an electronic device such as a mobile phone, a camera device using the linear drive device, and an electronic device.

  As a linear drive device (lens drive device) for driving a lens used in a conventional small camera device, there is a type that performs zooming and focusing by moving a lens support body linearly by vibrating a piezoelectric element. It was. This movement of the lens support is performed by frictionally coupling the lens support to the drive shaft connected to the piezoelectric element, and applying vibration to the drive shaft that the piezoelectric element reciprocates at different speeds, thereby causing friction between the drive shaft and the lens support. Is performed by changing with the reciprocation of this vibration. In this type of lens driving device, although the piezoelectric element is driven in the ultrasonic frequency region, noise in the audible region may be generated when the lens support moves.

  Therefore, in Patent Document 1, a large time constant drive voltage is applied to the piezoelectric element at the start of the movement of the lens support, and a slow start is applied. After a predetermined time has elapsed, a smaller time constant drive voltage is applied. As a result, generation of noise in the audible region can be suppressed.

JP 2012-124995 A

  The inventor of the present application further considered that the same idea is applied to the slow stop when the movement of the lens support is stopped in order to suppress the generation of noise. However, in the configuration of Patent Document 1, the position where the lens support stops is a position where the drive voltage gradually decreases to 0, and therefore the lens support does not always stop at the target stop position of the lens support. There is a problem. That is, the actual stop position with respect to the target stop position of the lens support varies. Further, when the driving voltage becomes smaller than a certain level, the friction state between the driving shaft and the lens support is hardly changed by the reciprocation of the vibration, so that the movement of the lens support stops even if the driving voltage does not become zero. End up. Therefore, the variation in the actual stop position with respect to the target stop position of the lens support is excessively large. Therefore, since the slow stop cannot be performed, there is a problem that the suppression of noise generation is not sufficient.

  Therefore, the present invention solves the above-described conventional problems, and realizes a slow stop with a stable stop position of a moving body such as a lens support, and sufficiently suppresses the generation of noise in the audible region. An object of the present invention is to provide a linear drive device that can perform the above-described operation.

  In order to achieve the above object, a linear drive device according to the present invention includes a drive member having a drive shaft coupled to a vibration member having a piezoelectric element that expands and contracts by a drive voltage having a repetitive waveform and vibrates with the vibration member, and the drive A movable body that is frictionally coupled to the drive shaft so as to be movable in the axial direction of the drive shaft by vibration of the shaft, and a position sensor that detects and outputs the position of the movable body in the axial direction. The voltage is controlled in accordance with the axial position of the moving body output from the position sensor, and the moving body until the moving body reaches the first predetermined position from the movement start position by this control. The moving speed of the moving body between the first predetermined position and the target stop position of the moving body is smaller than the moving speed of the moving body, and the movement stops when the moving body reaches the target stop position. Was to so that.

  With this configuration, the intended purpose can be achieved.

  According to the present invention, a drive member having a drive shaft that is coupled to a vibration member having a piezoelectric element that expands and contracts by a drive voltage having a repetitive waveform and vibrates with the vibration member, and an axial direction of the drive shaft by vibration of the drive shaft A movable body that is frictionally coupled to the drive shaft and a position sensor that detects and outputs the position of the movable body in the axial direction, and the drive voltage is output by the position sensor. It is controlled according to the position of the moving body in the axial direction. The driving voltage is controlled by the waveform until the movable body moves from the movement start position of the movable body toward the first predetermined position and reaches the first predetermined position according to the waveform. The moving speed of the moving body between the first predetermined position and the target stop position along the direction is smaller than the moving speed of the moving body, and the moving body has reached the target stop position. Sometimes the movement of the moving body stops. Thereby, even if the moving speed of the moving body before stopping is reduced, the moving body can be stopped at a stable position. Therefore, the effect that the slow stop where the stop position of the moving body is stable can be realized and the generation of noise in the audible region can be sufficiently suppressed can be obtained.

It is sectional drawing which shows the structure of the linear drive device of Embodiment 1 of this invention. It is a figure which shows the relationship between the drive voltage of Embodiment 1 of this invention, a drive shaft, and the displacement of a lens support body. It is a figure which shows the example of the drive voltage waveform of Embodiment 1 of this invention. It is a figure which shows the 1st modification of the drive voltage waveform of Embodiment 1 of this invention. It is a figure which shows the 2nd modification of the drive voltage waveform of Embodiment 1 of this invention. It is a figure which shows the 3rd modification of the drive voltage waveform of Embodiment 1 of this invention.

The invention according to claim 1 of the present invention provides
A drive member having a drive shaft coupled to a vibration member having a piezoelectric element that expands and contracts by a drive voltage having a repetitive waveform and vibrates with the vibration member;
A moving body frictionally coupled to the drive shaft so as to be movable in the axial direction of the drive shaft by vibration of the drive shaft;
A position sensor that detects and outputs the position of the moving body in the axial direction,
The drive voltage is controlled according to the position in the axial direction of the moving body output by the position sensor,
By the waveform, the moving body moves from the movement start position of the moving body toward the first predetermined position, and the moving speed of the moving body before reaching the first predetermined position is higher than the moving speed of the moving body. The moving speed of the moving body from the first predetermined position to the target stop position along the direction becomes smaller,
The linear drive device is characterized in that the drive voltage is controlled so that the movement of the moving body stops when the moving body reaches the target stop position.

  Therefore, even if the moving speed of the moving body before stopping is reduced, the moving body can be stopped at a stable position. Therefore, the effect that the slow stop where the stop position of the moving body is stable can be realized and the generation of noise in the audible region can be sufficiently suppressed can be obtained.

The invention according to claim 2 of the present invention is
According to the waveform, the driving voltage has a moving speed of the moving body from the second predetermined position to the second predetermined position closer to the movement start position than the first predetermined position in the direction. 2. The linear drive device according to claim 1, wherein the linear driving device is controlled so as to be smaller than a moving speed of the moving body between the first predetermined position and the first predetermined position.

  Since it is possible to realize a so-called slow start that slows the moving speed at the start of movement of the moving body, it is possible to suppress noise in the audible area that occurs when the moving body starts to move, and to move the moving body even more quietly. Can be realized.

The invention according to claim 3 of the present invention is
The drive voltage is controlled by the waveform such that the moving speed of the moving body from the first predetermined position to the target stop position of the moving body is gradually reduced. 2. The linear drive device according to 2.

  Since smooth deceleration can be performed, unnecessary wear of the coupling portion between the drive shaft and the moving body can be prevented, and a long-life linear drive device can be obtained.

The invention according to claim 4 of the present invention provides
3. The linear drive device according to claim 2, wherein the drive voltage is controlled by the waveform such that a moving speed of the moving body from the movement start position to the second predetermined position is gradually increased. It is.

  Since smooth acceleration can be achieved, unnecessary wear of the connecting portion between the drive shaft and the moving body can be prevented, and a long-life linear drive device can be obtained.

The invention according to claim 5 of the present invention provides
According to the waveform, the drive voltage is closer to the second predetermined position in two directions set in the direction between the second predetermined position and the first predetermined position. The moving speed of the moving body is maximum between 3 predetermined positions and a fourth predetermined position closer to the first predetermined position, and the moving speed between the second predetermined position and the third predetermined position. Is between the movement speed from the movement start position to the second predetermined position and the maximum movement speed, and the movement speed from the fourth predetermined position to the first predetermined position is the maximum 5. And a moving speed between the first predetermined position and a target stop position of the moving body. 5. This is a linear drive device.

  Even if the moving body is slow-started or slow-stopped, it can be accelerated and decelerated quickly and smoothly, so the travel time from the start of movement to the target stop position can be shortened.

The invention according to claim 6 of the present invention provides
6. The linear drive according to claim 5, wherein the driving voltage is controlled by the waveform so that a moving speed of the moving body from the second predetermined position to the third predetermined position gradually increases. Device.

  It is possible to accelerate the moving body more smoothly.

The invention according to claim 7 of the present invention provides
7. The linear device according to claim 5, wherein the driving voltage is controlled by the waveform such that a moving speed of the moving body from the fourth predetermined position to the first predetermined position is gradually decreased. It is a driving device.

  It is possible to decelerate the moving body more smoothly.

The invention according to claim 8 of the present invention provides
The linear drive device according to any one of claims 1 to 7, wherein the moving speed is changed in accordance with a change in frequency of the waveform.

  Since constant voltage control can be performed and the driving voltage does not change even when the moving speed decreases, the driving force in one cycle does not change. Therefore, unlike the prior art, it becomes difficult to move in the middle of the low voltage region, and the moving body can be reliably moved to the target stop position. Therefore, control is relatively easy.

The invention according to claim 9 of the present invention provides
9. The linear drive device according to claim 1, wherein the vibration member includes an elastic substrate, and the piezoelectric element is attached to at least one surface of the elastic substrate. 10.

  Since it can be set as a thin vibration member, it can be set as a thin linear drive device.

The invention according to claim 10 of the present invention provides
10. The linear drive device according to claim 1, wherein the moving body includes a lens and is a lens support for supporting the lens.

  Even if the moving speed of the lens support before stopping is reduced, the lens support can be stopped at a stable position. Therefore, an effect that a slow stop with a stable stop position of the lens support body is realized and noise in the audible region can be sufficiently suppressed can be obtained.

The invention according to claim 11 of the present invention provides
Two sets of the drive members, the lens support, and the position sensor are provided, one set for the zoom lens and the other set for the focus lens. The driving direction and the optical axis of the lens support driven by both sets of drive members The linear drive device according to claim 10, wherein

  Since it arrange | positions based on the same optical axis, a linear drive device can be reduced in size.

The invention according to claim 12 of the present invention provides
A lens that focuses the light from the subject,
An image sensor that receives and outputs light from the subject focused by the lens;
A drive member having a vibration member having a piezoelectric element that can be expanded and contracted by a drive voltage having a repetitive waveform; and a drive shaft that vibrates together with the vibration member;
A lens support that is frictionally coupled to the drive shaft so as to be movable in the axial direction of the drive shaft by vibration of the drive shaft and supports the lens;
A position sensor that detects and outputs the position of the lens support in the axial direction;
A drive control unit that generates a driving voltage of the repetitive waveform according to the axial position of the lens support output by the position sensor and applies the driving voltage to the piezoelectric element;
The drive voltage generated by the drive control unit is controlled according to the axial position of the lens support output from the position sensor, and the movement of the lens support is started by the waveform. The lens support moves in the direction from the position toward the first predetermined position, and the moving speed of the lens support from the position until reaching the first predetermined position in the direction from the first predetermined position. The movement speed of the lens support until reaching the target stop position along is smaller, and the movement of the lens support stops when the lens support reaches the target stop position. It is a camera device characterized by being controlled.

  Generation of noise in the audible region of the lens driving device can be sufficiently suppressed. Therefore, the camera apparatus is also quiet, and an effect is obtained that the lens can be moved even during moving image shooting.

The invention according to claim 13 of the present invention provides
An electronic apparatus comprising the camera device according to claim 12.

  Since the camera device is quiet, an effect is obtained that the lens can be moved even during moving image shooting with the camera device provided in the electronic device.

(Embodiment 1)
Hereinafter, the linear drive apparatus 10 in Embodiment 1 of this invention is demonstrated, referring drawings.

  As shown in FIG. 1, the electronic apparatus 1 includes a camera device 3, and the camera device 3 includes a linear drive device 10.

  The electronic device 1 includes, for example, portable devices such as a mobile terminal device typified by a mobile phone or a smartphone or a palm-sized personal computer. In addition, stationary devices such as surveillance camera systems are also included.

  In the first embodiment, the linear driving device 10 is a lens driving device for driving a zoom lens and / or a focus lens.

  The linear drive device 10 includes drive members 22 and 42, lens supports 26 and 46 as moving bodies, and position sensors 28 and 48.

  The drive members 22, 42 have drive shafts 20, 40 that are coupled to the vibration members 18, 38 having the piezoelectric elements 14, 34 that are expanded and contracted by a repetitive waveform drive voltage and vibrate with the vibration members 18, 38.

  The lens supports 26 and 46 are frictionally coupled to the drive shafts 20 and 40 so as to be movable in the axial direction of the drive shafts 20 and 40 by vibrations of the drive shafts 20 and 40.

  The lens supports 26 and 46 are for supporting the lenses 24 and 44 that focus light from a subject (not shown) on the image sensor 56.

  The position sensors 28 and 48 detect and output the positions of the lens supports 24 and 44 in the axial direction.

  Here, the lens 24 is a zoom lens, and the drive member 22, the lens support 26, and the position sensor 28 are a set for a zoom lens.

  The lens 44 is a focus lens, and the driving member 42, the lens support 46, and the position sensor 48 are a group for the focus lens.

  The drive members 22 and 42 include the vibration members 18 and 38 and the drive shafts 20 and 40.

  The vibration members 18 and 38 are configured by attaching the piezoelectric elements 14 and 34 to at least one surface of the elastic substrates 16 and 36.

  The elastic substrates 16 and 36 are metal plates such as copper having elasticity.

  The piezoelectric elements 14 and 34 are elements having a piezoelectric effect such as PZT (lead zirconate titanate).

  Power supply terminals (not shown) are provided on both surfaces of the piezoelectric elements 14 and 34. One of the power supply terminals may also serve as the elastic substrates 16 and 36.

  Although FIG. 1 shows an example of a so-called unimorph type in which the piezoelectric elements 14 and 34 are attached to one surface of the elastic substrates 16 and 36, a so-called bimorph type in which the piezoelectric elements 14 and 34 are attached to both surfaces of the elastic substrates 16 and 36 is shown. It does not matter. Also, a so-called laminated type may be used.

  The drive shafts 20 and 40 are shafts made of lightweight carbon or the like, and end surfaces at one ends thereof are fixed to one surface of the vibration members 16 and 36. Fixing may be adhesive. You may make it the area of the end surface of the drive shafts 20 and 40 fixed become smaller than the area of a shaft main-body part. Since the area contributing to the vibration of the vibration members 16 and 36 described later increases accordingly, the driving force can be increased even if the outer diameter dimensions of the vibration members 16 and 36 are the same.

  The drive members 22 and 42 are fixed to the housing 12 by supporting both ends of the drive shafts 20 and 40 by being elastically pressed from the outer peripheral side by rubber bushes 52. Therefore, the vibration members 18 and 38 are not in contact with the outside except for the drive shafts 22 and 42 and the power supply related members. Therefore, there is no vibration attenuation due to contact with an external member, so that the driving force transmitted to the drive shafts 20 and 40 is large.

  The ends of the drive shafts 20 and 40 opposite to the vibration members 16 and 36 are bonded and fixed to the rubber bush 52, but the ends near the vibration members 16 and 36 are not bonded.

  The lens supports 26 and 46 are disposed in the main body of the drive shafts 20 and 40 while being supported by both rubber bushings 52.

  The drive shafts 20 and 40 are assembled so that the axial directions thereof coincide with the optical axis direction.

  The lens supports 26 and 46 are made of resin and have a hole at the center so that the lenses 24 and 44 can be supported. The contact portions of the lens supports 26 and 46 with the drive shafts 20 and 40 are made of metal members, and are urged by a spring or the like so as to be in line contact with the drive shafts 20 and 40 and are frictionally coupled. Since they are only frictionally coupled, the lens supports 26 and 46 can move on the drive shafts 20 and 40 along the axial direction.

  The opposite side of the lens support 26, 46 that is frictionally coupled to the drive shafts 20, 40 is U-shaped and engaged with the shaft members 40, 20 so that the lens supports 26, 46 are driven. It does not rotate around the shafts 20 and 40.

  The housing 12 is an exterior of the linear drive device 10, and the drive members 22, 42, the lens supports 26, 46, the position sensors 28, 48, and the like are arranged at predetermined positions. The housing 12 is made of resin, and is provided with a hole for placing the lens 54 at the center of the subject side and an opening for placing the substrate 58 with the image sensor 56 attached to the side opposite to the subject side. .

  Light from the subject is focused on the image sensor 56 through the lenses 54, 24 and 44. The light received by the image sensor 56 is converted into an electrical signal and output to the camera device 3 body.

  The position sensors 28 and 48 are sensors for detecting the positions of the lens supports 26 and 46 in the axial direction and outputting them to the drive controller 60.

  In the first embodiment, the MR sensor is provided on the lens supports 26 and 46, and the scales 30 and 50 are provided on the housing 12 as magnetic scales. As the scales 30 and 50, magnetic poles directed to the position sensors 28 and 48 are alternately arranged in the optical axis direction.

  The position sensors 28 and 48 and the scales 30 and 50 may be arranged on either the lens support 26 or 46 or the housing 12. In the first embodiment, MR sensors are used as the position sensors 28 and 48. However, Hall sensors or the like may be used, and the scales 30 and 50 need not be used depending on the sensor type.

  The drive control unit 60 moves the lens supports 26 and 46 by applying a driving voltage having a repetitive waveform as shown in FIG. 2 to the piezoelectric elements 14 and 34. In the first embodiment, the repetitive waveform is a rectangular wave.

  When a rectangular wave is applied (T0), first, the piezoelectric elements 14 and 34 expand in the thickness direction and contract in the in-plane direction. The voltage rises abruptly, but deforms against the elasticity of the elastic substrates 16 and 36, so that the deformation proceeds relatively slowly, and the vibrating members 18 and 38 become bows so that the central part moves upward in FIG. Transforms into

  As the vibrating members 18 and 38 are deformed, the drive shafts 20 and 40 and the lens supports 26 and 46 also move upward.

  When deformation is performed to a deformation amount corresponding to the voltage value (T1), while the voltage is constant (T1 → T2), the vibration members 18 and 38 maintain their postures, and when the voltage becomes 0 (T2), the piezoelectric element 14 , 34 is released, and the deformation of the vibration members 18, 38 returns to the original state in an instant due to the elastic force of the elastic substrates 16, 36. Along with this, the drive shafts 20 and 40 also return to their original positions (T2 → T3).

  However, the lens supports 26 and 46 remain in place because the inertial force overcomes the frictional force of the frictional engagement. For this reason, the lens supports 26 and 46 are moved by the amount of deformation of the vibrating members 18 and 38 by the drive voltage by applying one period of the rectangular wave (T0 → T4).

  By repeating this, the lens supports 26 and 46 move upward in FIG. When moving downward, the drive voltage is applied in reverse.

  Although the piezoelectric elements 14 and 34 are driven in the ultrasonic frequency region, conventionally, noise in the audible region may be generated when the lens supports 26 and 46 are moved.

  Next, the waveform of the drive voltage generated by the drive control unit 60 in the first embodiment will be described.

  As shown in FIG. 3, the drive control unit 60 controls the drive voltage according to the axial positions of the lens supports 26 and 46 detected and output by the position sensors 28 and 48.

  That is, when the drive control unit 60 detects that the lens supports 26 and 46 have reached predetermined positions such as the first predetermined position P1 and the second predetermined position P2, the drive control unit 60 changes the frequency of the drive voltage. Thus, the moving speed of the lens supports 26 and 46 is changed.

  The drive voltage is a repetitive waveform corresponding to the axial position of the lens supports 26 and 46 output from the position sensors 28 and 48. As described above, the repetitive waveform is a rectangular wave.

  The driving voltage is applied to the lens support until the lens supports 26 and 46 move from the movement start position Pstart of the lens supports 26 and 46 toward the first predetermined position P1 and reach the first predetermined position P1. The moving speed of the lens supports 26, 46 before reaching the target stop position Pstop of the lens supports 26, 46 along the axial direction from the first predetermined position P 1 than the moving speed of the bodies 26, 46. It has a repetitive waveform that is made small.

  The lens supports 26 and 46 have a repetitive waveform in which the movement of the lens supports 26 and 46 stops when the lens supports 26 and 46 reach the target stop position Pstop.

  In the first embodiment, the moving speed of the lens supports 26 and 46 corresponds to the frequency of the repetitive waveform.

  That is, the frequency between the first predetermined position P1 and the target stop position Pstop is made smaller than the frequency until the lens supports 26 and 46 reach the first predetermined position P1.

  As shown in FIG. 2, when the driving voltage is the same, the displacement of the lens supports 26 and 46 in one cycle is the same. Therefore, the moving speed of the lens supports 26 and 46 decreases as the frequency of the driving voltage decreases.

  Since the slow stop can be realized when the lens supports 26 and 46 are stopped, the generation of noise in the audible region can be sufficiently suppressed.

  Further, when the position sensors 28 and 48 detect and output that the lens supports 26 and 46 have reached the target stop position Pstop, the drive control unit 60 stops applying the drive voltage. When the application of the driving voltage is stopped, the lens supports 26 and 46 stop moving.

  Therefore, the linear drive device 10 according to the first embodiment can stop the lens supports 26 and 46 at a stable position even if the moving speed of the lens supports 26 and 46 before stopping is reduced.

  In the first embodiment, as the constant voltage driving, the moving speed is controlled according to the frequency of the repetitive waveform. Therefore, the driving voltage does not change even if the moving speed decreases, and in one cycle. The driving force does not change. Therefore, unlike the prior art, it is unlikely to become a low voltage region and stop moving halfway, and the lens supports 26 and 46 can be reliably moved to the target stop position Pstop. Therefore, control is relatively easy.

  The lens supports 26 and 46 move at a high speed to the first predetermined position P1 and move at a low speed only from the last first predetermined position P1 to the target stop position Pstop. Can be completed.

  In addition, as shown in FIG. 3, in the first embodiment, so-called slow start that slows the moving speed at the start of movement of the lens supports 26 and 46 is also realized. In FIG. 3, a second predetermined position P2 closer to the movement start position Pstart than the first predetermined position P1 is set in the axial direction. The driving voltage is such that the moving speed of the lens supports 26, 46 from the movement start position Pstart of the lens supports 26, 46 to the second predetermined position P2 is from the second predetermined position P2 to the first predetermined position. The waveform was smaller than the moving speed of the lens supports 26 and 46 up to P1.

  Also in the case of this slow start, the moving speed of the lens supports 26 and 46 is reduced by reducing the frequency of the drive voltage at the start of movement.

  Since so-called slow start that slows the moving speed at the start of movement of the lens supports 26 and 46 can be realized, noise in the audible region that occurs at the start of movement of the lens supports 26 and 46 can also be suppressed. Therefore, the movement of the lens supports 26 and 46 can be realized more quietly than when only the slow stop is used.

  The lens supports 26 and 46 move at a high speed from the second predetermined position P2 to the first predetermined position P1, and only at a low speed from the start of movement to the second predetermined position P2 and from the first predetermined position P1 to the stop. Since it moves, the movement can be completed in a short time as a whole.

  Here, the first predetermined position P1 and the second predetermined position P2 may be set in advance, for example, 20% and 80% positions from the movement start position Pstart to the target stop position Pstop, respectively. It is.

  In FIG. 3, the frequency and distance from the movement start position Pstart to the second predetermined position P2 and the frequency and distance from the first predetermined position P1 to the target stop position Pstop are expressed as being the same. May be set individually. The same applies to modified examples described later.

  In the first embodiment, the waveform of the drive voltage is drawn with a duty ratio of 50%, but other duty ratios may be used. Further, when changing the frequency of the drive voltage, the frequency of the drive voltage may be changed so that the duty ratio is not constant but one pulse width is constant. The same applies to the modified examples described later.

  In the first embodiment, the waveform of the drive voltage does not have to be a rectangular pulse, and may be, for example, a sawtooth waveform, or a waveform like a sine wave if the speed can be changed by driving. It doesn't matter. The movement speed is changed by changing the frequency of the drive voltage. However, for example, the drive voltage value may be changed or may be combined. The same applies to the modifications described later.

  Next, a first modification of the drive voltage waveform in the first embodiment will be described.

  As shown in FIG. 4, in the first modification, the driving voltage gradually decreases in the moving speed of the lens supports 26 and 46 from the first predetermined position P1 to the target stop position Pstop of the lens supports 26 and 46. Waveform. That is, in the first modification, the frequency of the driving voltage is gradually decreased from the first predetermined position P1 to the target stop position Pstop of the lens supports 26 and 46.

  Further, the drive voltage has a waveform in which the moving speed of the lens supports 26 and 46 from the movement start position Pstart to the second predetermined position P2 gradually increases. That is, the frequency of the drive voltage is gradually increased between the movement start position Pstart and the second predetermined position P2.

  Since the moving speed of the lens support 26, 46 from the first predetermined position P1 to the target stop position Pstop of the lens support 26, 46 is gradually reduced, smooth deceleration can be performed, so that the drive shafts 20, 40 and the lens Unnecessary wear of the joint portions of the supports 26 and 46 can be prevented, and the long-life linear drive device 10 can be obtained. Similarly, since the moving speed of the lens supports 26 and 46 from the movement start position Pstart to the second predetermined position P2 is gradually increased, smooth acceleration can be performed, so that the drive shafts 20 and 46 and the lens support 10 Unnecessary wear of the coupling portion can be prevented, and the long-life linear driving device 10 can be obtained.

  Further, since the position sensor 28.48 detects that the lens supports 26, 46 have reached the target stop position Pstop, the movement of the lens supports 26, 46 is stopped, so that the lens supports 26, 46 are moved. Even if the speed decreases gradually, it can stop at a stable position.

  Next, a second modification of the drive voltage waveform of the first embodiment will be described.

  As shown in FIG. 5, in the second modified example, the third predetermined position P3 and the fourth predetermined position which are two predetermined positions between the second predetermined position P2 and the first predetermined position P1 in the axial direction. Position P4 was set.

  The drive voltage has the maximum moving speed of the lens supports 26 and 46 from the third predetermined position P3 closer to the second predetermined position P2 to the fourth predetermined position P4 closer to the first predetermined position P1. The waveform was as follows.

  In addition, the waveform is such that the movement speed from the second predetermined position P2 to the third predetermined position P3 is intermediate between the movement speed from the movement start position Pstart to the second predetermined position P2 and the maximum movement speed. I made it.

  Furthermore, the moving speed between the fourth predetermined position P4 and the first predetermined position P1 is the maximum moving speed and the moving speed between the first predetermined position P1 and the target stop position Pstop of the lens supports 26 and 46. The waveform was in the middle.

  Since finer control is possible, the movement of the lens supports 26 and 46 can be completed more silently and in a shorter time.

  Moreover, as shown in FIG. 6, it is good also as a waveform from which the moving speed between the 2nd predetermined position P2 to the 3rd predetermined position P3 increases gradually. Moreover, it is good also as a waveform from which the moving speed between the 4th predetermined position P4 and the 1st predetermined position P1 reduces gradually. The lens supports 26 and 46 can be accelerated or decelerated more smoothly.

  Although not shown, the waveform may be a waveform in which the movement speed between the movement start position Pstart and the second predetermined position P2 gradually increases, or the movement speed between the first predetermined position P1 and the target stop position Pstop gradually decreases. It is good also as a waveform to do.

  Alternatively, either the third predetermined position P3 or the fourth predetermined position P4 may be omitted, and the waveform shown in FIG. 3 or 4 may be combined with the waveform shown in FIG. 5 or FIG.

  In the first embodiment, the description has been made up to the fourth predetermined position P4, but the fifth predetermined position P5 and after may be increased.

  In the first embodiment, the linear driving device 10 is a lens driving device for driving a zoom lens and / or a focus lens. However, the present invention is not limited to this. For example, a lens or an image sensor driving device that corrects camera shake by driving a lens in a direction orthogonal to the optical axis or driving an image sensor in an in-plane direction may be used. Absent. In this case, the moving body is a lens support that supports the camera shake correction lens or an image sensor support that supports the image sensor.

DESCRIPTION OF SYMBOLS 1 Electronic device 3 Camera apparatus 10 Linear drive device 12 Case 14, 34 Piezoelectric element 16, 36 Elastic board 18, 38 Vibration member 20, 40 Drive shaft 22, 42 Drive member 24, 44, 54 Lens 26, 46 Lens support body (Moving body)
28, 48 Position sensors 30, 50 Scale 52 Rubber bushing 56 Image sensor 58 Substrate 60 Drive controller

Claims (13)

A drive member having a drive shaft coupled to a vibration member having a piezoelectric element that expands and contracts by a drive voltage having a repetitive waveform and vibrates with the vibration member;
A moving body frictionally coupled to the drive shaft so as to be movable in the axial direction of the drive shaft by vibration of the drive shaft;
A position sensor that detects and outputs the position of the moving body in the axial direction,
The drive voltage is controlled according to the position in the axial direction of the moving body output by the position sensor,
By the waveform, the moving body moves from the movement start position of the moving body toward the first predetermined position, and the moving speed of the moving body before reaching the first predetermined position is higher than the moving speed of the moving body. The moving speed of the moving body from the first predetermined position to the target stop position along the direction becomes smaller,
The drive voltage is controlled so that the movement of the moving body stops when the moving body reaches the target stop position.   According to the waveform, the driving voltage has a moving speed of the moving body from the second predetermined position to the second predetermined position closer to the movement start position than the first predetermined position in the direction. The linear drive device according to claim 1, wherein the linear drive device is controlled so as to be smaller than a moving speed of the moving body between the first predetermined position and the first predetermined position.   The drive voltage is controlled by the waveform such that the moving speed of the moving body from the first predetermined position to the target stop position of the moving body is gradually reduced. The linear drive device according to 2.   3. The linear drive device according to claim 2, wherein the drive voltage is controlled by the waveform such that a moving speed of the moving body from the movement start position to the second predetermined position is gradually increased. .   According to the waveform, the drive voltage is closer to the second predetermined position in two directions set in the direction between the second predetermined position and the first predetermined position. The moving speed of the moving body is maximum between 3 predetermined positions and a fourth predetermined position closer to the first predetermined position, and the moving speed between the second predetermined position and the third predetermined position. Is between the movement speed from the movement start position to the second predetermined position and the maximum movement speed, and the movement speed from the fourth predetermined position to the first predetermined position is the maximum 5. And a moving speed between the first predetermined position and a target stop position of the moving body. 5. Linear drive device.   6. The linear drive according to claim 5, wherein the driving voltage is controlled by the waveform so that a moving speed of the moving body from the second predetermined position to the third predetermined position gradually increases. apparatus.   7. The linear device according to claim 5, wherein the driving voltage is controlled by the waveform such that a moving speed of the moving body from the fourth predetermined position to the first predetermined position is gradually decreased. Drive device.   8. The linear driving apparatus according to claim 1, wherein the moving speed is changed in accordance with a change in the frequency of the waveform.   The linear drive device according to claim 1, wherein the vibration member includes an elastic substrate, and the piezoelectric element is attached to at least one surface of the elastic substrate.   The linear driving apparatus according to claim 1, wherein the moving body includes a lens and is a lens support for supporting the lens.   Two sets of the drive members, the lens support, and the position sensor are provided, one set for the zoom lens and the other set for the focus lens. The driving direction and the optical axis of the lens support driven by both sets of drive members The linear drive device according to claim 10, wherein: A lens that focuses the light from the subject,
An image sensor that receives and outputs light from the subject focused by the lens;
A drive member having a vibration member having a piezoelectric element that can be expanded and contracted by a drive voltage having a repetitive waveform; and a drive shaft that vibrates together with the vibration member;
A lens support that is frictionally coupled to the drive shaft so as to be movable in the axial direction of the drive shaft by vibration of the drive shaft and supports the lens;
A position sensor that detects and outputs the position of the lens support in the axial direction;
A drive control unit that generates a driving voltage of the repetitive waveform according to the axial position of the lens support output by the position sensor and applies the driving voltage to the piezoelectric element;
The drive voltage generated by the drive control unit is controlled according to the axial position of the lens support output from the position sensor, and the movement of the lens support is started by the waveform. The lens support moves in the direction from the position toward the first predetermined position, and the moving speed of the lens support from the position until reaching the first predetermined position in the direction from the first predetermined position. The movement speed of the lens support until reaching the target stop position along is smaller, and the movement of the lens support stops when the lens support reaches the target stop position. A camera device that is controlled.   An electronic apparatus comprising the camera device according to claim 12.