JP2004029405A - Lens driving apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens driving apparatus which can perform positioning of lenses with excellent accuracy without causing a noise when driving a cam disc. <P>SOLUTION: A driving groove 117c is provided in the cam disc 117 and driving pins 118b and 119c which can move in the driving groove 117c according to change of thickness of piezo-electric elements 118 and 119, are disposed in the driving groove 117c respectively. Two piezo-electric elements 118 and 119 are controlled by voltage applied from the outside, change of thickness is given, the driving pins 118b and 119b are moved, and thereby the cam disc 117 can be moved. Two cam grooves 117a and 117b are provided in the movable cam disc 117, cam followers 113b and 114b of lens holding frames 113a and 114a are engaged to the cam grooves 117a,117b respectively. Thereby, each of lenses 113 and 114 moves together with the lens holding frame calmly and with high accuracy. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a lens driving device that drives a lens.
[0002]
[Prior art]
In recent years, the miniaturization of camera bodies has been promoted, and a large number of small, lightweight, and portable cameras have been released. As such cameras have been reduced in size, attention has been focused on cameras having a thin structure that is more convenient to carry, in addition to miniaturization.
[0003]
In pursuing the miniaturization of camera bodies, parts such as lenses for photographing and members for holding those parts, parts for CCD solid-state imaging devices, and members for holding the CCD solid-state imaging devices, etc., are downsized. The miniaturized parts and members are mounted at high density in the miniaturized camera body.
[0004]
However, no matter how small these parts or members are, the lens group that focuses the subject light captured via the objective lens on the shooting surface of the CCD solid-state image sensor as in the past is linearly arranged in the camera body. When it is provided, there is another problem that the camera body does not become thinner. The optics that can change the direction of the light by bending the light guided from the objective window for imaging with a reflector provided in the camera, and then allow the lens group to be positioned freely. The system has been deployed in the camera body, and the thickness has been reduced.
[0005]
In such a thinned camera, the lens driving device for adjusting the focal length and the relative position between the lenses for achieving the optical zoom must also be compatible with the thin structure of the camera body. Must. A motor used as a driving source of such a lens driving device is a motor. However, although the motor is downsized, it is difficult to find a motor suitable for the thin structure of the camera body. Therefore, the use of small piezoelectric elements as drive sources instead of motors is increasing.
[0006]
In a lens driving device using this piezoelectric element, a rod is connected to the piezoelectric element, a lens frame is fixed to the connected rod, the thickness of the piezoelectric element is periodically changed, and the lens frame is moved together with the rod. Even though the lens frame is moved, the dimensions of the piezoelectric element are fixed, and while the lens frame is simply fixed to the rod fixed to the piezoelectric element, a change in the thickness of the piezoelectric element is obtained. If only the lens frame can be moved, it is impossible to move the lens frame beyond a distance necessary for adjusting the focal length and the like. Therefore, when a change in the direction in which the thickness of the piezoelectric element increases or shrinks appears in the piezoelectric element, the rate of change is slowed down and the lens frame is moved with the rod, and when the other change appears in the piezoelectric element, the change rate is used. Is controlled so as to move only the rod by speeding up. In this method, the magnitude of the friction between the rod and the lens frame is adjusted by changing the change speed of the thickness of the piezoelectric element, and the lens frame is driven. As a lens driving device to which the technique for performing such control is applied, there is one disclosed in Japanese Patent Application Laid-Open No. 9-191676.
[0007]
The operation of a driving device using the piezoelectric element described in this publication as a driving source will be described.
[0008]
FIG. 11 is a diagram showing the relationship between a piezoelectric element and a moving body such as a lens frame, and FIG. 12 is a diagram showing a control voltage applied to the piezoelectric element.
[0009]
As shown in FIG. 12, a rod 20 is connected to the piezoelectric element 10, and a lens frame is connected to the rod 20 with a predetermined frictional force. When a sawtooth wave as shown in FIG. 12 is applied to the piezoelectric element 10, the above-described control is performed.
[0010]
That is, in the portion A of the sawtooth wave shown in FIG. 12, a voltage gradually increasing from the reference voltage to the peak voltage is applied to the piezoelectric element 10, and the piezoelectric element 10 is slowly extended, and the slow piezoelectric As the element 10 expands, the moving body 30, for example, the lens frame moves from a position O shown in FIG. 11A to a position P shown in FIG. 11B. After the voltage that has reached the peak voltage is held, in the portion B of the sawtooth wave shown in FIG. 12, a voltage that rapidly drops to near the reference voltage is applied to the piezoelectric element 10, and the piezoelectric element 10 is moved to the state shown in FIG. The state shown in FIG. 11B suddenly contracts from the state shown in FIG. 11B to the state shown in FIG. 11C, and accordingly, the rod 20 rapidly moves to the left side in FIG. At this time, the moving body 30, for example, the lens frame cannot follow the contraction speed of the piezoelectric element 10, and only the rod 20 contracts while the moving body 30, for example, the lens frame remains at the position P. Then, the moving body 30, for example, the lens frame moves from the original position O to the position P as shown in FIG. By repeating this, the moving body moves to the right side in FIG.
[0011]
On the other hand, in order to move the moving body 30 to the left side of FIG. 11, the piezoelectric element 10 has a waveform opposite to the waveform shown in FIG. 12, that is, the portion A of the sawtooth waveform shown in FIG. In the part, the driving may be performed with a waveform in which the voltage gradually decreases.
[0012]
By repeatedly giving a change in thickness to the piezoelectric element in this manner, it becomes possible to provide a movement distance greater than the change in thickness of the piezoelectric element to the lens frame.
[0013]
The above is the driving principle of the driving device proposed in the above publication.
[0014]
However, with such a control method, the state of friction between the lens frame and the rod is not accurately grasped, so that it is possible to drive the lens to a predetermined position by changing the thickness of the piezoelectric element several times. Can not be measured exactly. Therefore, it has been considered to use a cam mechanism together and accurately determine the position of the lens frame by the cam mechanism. One of them is shown in FIG.
[0015]
FIG. 13 shows a lens driving device using the principle described with reference to FIGS. 11 and 12, which is an example in which positioning teeth are provided on a cam plate in order to increase positional accuracy.
[0016]
FIG. 13A is a diagram showing a piezoelectric element used as a drive source and a transmission unit that transmits a change in the thickness of the piezoelectric element to the cam plate 1 as a driving force, and FIG. 13B shows the transmission unit. FIG. 3 is a view showing a cam plate 1 to which a driving force is transmitted by the driving force.
[0017]
As shown in FIG. 13B, the cam plate 1 is provided with cam grooves 1a and 1b, and a lens holding frame (not shown) is engaged with the cam grooves 1a and 1b. At the end of the cam plate 1, teeth 1 c which draw a sawtooth waveform for controlling the position of the lens holding frame with high precision are provided in a row, and the teeth 1 c having the sawtooth waveform are provided. A claw 5a of a ratchet 5 shown in FIG. 13A for transmitting a change in the thickness of the piezoelectric element 2 to the cam plate 1 as a driving force is engaged with the portion. The period of the sawtooth waveform is a measure of the movement distance of the lens. A piezoelectric element 2 is provided on one side of the ratchet 5 via a connecting member 3, and a movement due to a change in the thickness of the piezoelectric element 2 is transmitted to the ratchet 5 as a driving force. The ratchet 5 is movably engaged with a projection 3a provided on the connecting member 3, and a return spring 4 is disposed around the projection 3a. One end of the return spring 4 is engaged with the projection 3b on the connecting member 3 side, and the other end is engaged with the projection 5b provided on the ratchet 5 side. Therefore, the pawl 5a of the ratchet 5 is always biased toward the tooth 1c.
[0018]
When the thickness of the piezoelectric element 2 changes and contracts in the above configuration, the cam plate 1 moves in the direction of the arrow in the figure. This is because the claw 5a of the ratchet 5 moves in the direction opposite to the arrow when the piezoelectric element 2 contracts. When the thickness of the piezoelectric element begins to shrink, the teeth of the ratchet begin to slide along the slope, and the urging force of the return spring 4 disposed so as to be wound around the convex portion 3a of the connecting member 3 causes the cam plate 1 to move. It climbs while sliding on the inclination of the tooth 1c. Then, when the tip of the pawl 5a of the ratchet 5 exceeds the end of the inclination of the tooth 1c, the nail enters into the concave side of the next adjacent tooth 1c. If the piezoelectric element 1 continues to shrink, the ratchet claw 5a is further driven into the next tooth 1c side, and the cam plate is driven in the direction of the arrow. Conversely, when the piezoelectric element 2 is extended, the ratchet claw starts to tilt about the portion where the inclination of the claw 5a of the ratchet 5 and the inclination of the teeth 1c contact each other, and the tip of the claw 5a rides over the edge of the tooth 1c, The pawl 5a is urged by the return spring 4 toward the cam plate 1 and enters the next adjacent tooth recess.
[0019]
[Problems to be solved by the invention]
However, in order to apply a driving force to the cam plate, a driving mechanism for driving the cam plate with a driving source is required. When such a drive mechanism is provided, a place where the drive source side and the cam plate side vigorously come into contact with each other occurs, as can be seen from the above-described example, so that a problem arises in that noise is generated therefrom.
[0020]
The present invention has been made in view of the above circumstances, and has as its object to provide a lens driving device having a highly accurate positioning function in which a driving source side and a cam plate side do not abut vigorously.
[0021]
[Means for Solving the Problems]
A lens driving device of the present invention that achieves the above object, a lens holding frame that holds a lens having a cam follower,
A cam member having a cam groove in which the cam follower is fitted and moving the lens via a cam mechanism including the cam groove and the cam follower;
A drive source for driving the cam member,
The cam member has a driving groove for receiving a driving force of the driving source,
The drive source includes a piezoelectric element, a rod having one end fixed to the piezoelectric element, and transmitting a change in the thickness of the piezoelectric element, and a rod fixed to the rod and moving into the drive groove to move the rod to the cam member. It is characterized by comprising a plurality of drive members having a drive pin for transmitting.
[0022]
According to the lens driving device of the above invention, the change in the thickness of the piezoelectric element is transmitted to the driving pin via the rod, and the driving pin is moved along the driving groove of the cam member to be fitted into the cam groove of the cam member. The driving force is transmitted to the cam follower, and the lens can be moved together with the lens holding frame provided with the cam follower. When the lens is moved, the drive pin inserted into the drive groove of the cam plate only moves along the drive groove, and there is no place where the drive source side and the cam plate side come into contact with each other. Can be.
[0023]
Here, the driving groove is a groove having a shape extending in the moving direction of the cam member while drawing a sinusoidal waveform,
It is preferable that the plurality of driving members are arranged in the direction in which the driving groove extends, and are arranged at positions where the sinusoidal waveforms have mutually different phases.
[0024]
When the drive pin of the drive member is provided so as to enter the drive groove that draws a sine waveform, the smaller the groove that draws the sine waveform, the finer the position of the cam member can be controlled. However, if only one drive pin is provided in the drive groove that draws a sinusoidal waveform, the drive that moves according to the change in the thickness of the piezoelectric element when the drive pin is at the peak or valley position of the sine wave The direction in which the pin moves may not be determined. Therefore, a plurality of drive pins are provided at different positions of the sine waveform, and when one drive pin is located at the peak or valley of the sine waveform, the other drive pins are not positioned at the peak or valley of the sine waveform. It is preferable that the pins located at the peaks or valleys be moved smoothly by the driving force applied to the other pins.
[0025]
Here, the driving groove is a groove having a shape extending in the moving direction of the cam member while drawing a rectangular waveform,
It is preferable that the plurality of driving members are rotatable, have a common driving pin inserted into the driving groove, and move the driving pins in mutually different directions.
[0026]
In this way, a common drive pin is inserted into the groove that draws a rectangular waveform, and the drive pins are moved in different directions by a plurality of drive members, respectively, so that only one drive pin is provided without providing a plurality of drive pins. Can move the cam member. However, if the plurality of driving members are kept fixed when the common driving pin is moved in different directions by the plurality of driving members, the movement of the driving pin driven by any one of the driving members may be affected. It may cause trouble. Therefore, when any one of the plurality of driving members is driving a common driving pin, the other driving member is rotated, and the movement of the driving pin driven by any one of the driving members is performed. Is preferably smoothed.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0028]
FIG. 1 shows an embodiment of a lens driving device according to the present invention, and is a view showing an appearance of a camera provided with the lens driving device.
[0029]
FIG. 1A is a perspective view showing the configuration of the camera, and FIG. 1B is a rear view of the camera shown in FIG. Further, FIG. 1C is a diagram in which a configuration of a photographing optical system including an objective lens is extracted.
[0030]
As shown in FIG. 1A, a camera body 101 of a camera 100 according to the present embodiment has a thin structure, and a camera optical system 110 and a flash light emitting device are provided in the camera body 101. On the surface of the camera body 101, an objective lens 1011a for guiding the subject light to a lens group disposed inside the camera body 101 and a flash emission window 1011c for emitting the flash of the flash light emitting device toward the subject are provided. 1011b is provided. The camera 100 of the present embodiment is also provided with a finder window 101b, so that the subject light guided through the finder window 101b can be visually recognized by an eyepiece (not shown) provided on the back side of the camera. I have. Note that the objective lens 1011a, the objective window 101b of the finder, and the flash light emission window 101c are made of a member 1011 integrally molded.
[0031]
The camera 100 also has an automatic focus adjustment function, and the focus is automatically adjusted when the release button 102 is pressed. Further, a zoom switch 103 is provided, and when the zoom switch 103 is operated, optical zoom can be performed.
[0032]
The camera is also provided with an LCD display device, and on the back side of the camera body 101, a display panel 120 of the LCD display device is provided. Framing can also be performed on the subject image on the display panel 120. Framing can be performed with either the subject image displayed on the display panel 120 of the LCD display device or the subject image visually recognized through the viewfinder, and the photographing can be performed by pressing the release button 102.
[0033]
Here, the photographing optical system will be described with reference to FIG. The camera of this embodiment is provided with a photographing optical system using a reflecting mirror 111. The subject light guided via the objective lens 101a disposed on the surface of the camera body is bent by the reflecting mirror 111 in a direction substantially orthogonal to the optical axis of the objective lens 101a, and the bent subject light is reflected later. The light is guided to the CCD solid-state imaging device 116 by the group of lenses 112 to 115, and an image is formed on the imaging surface of the CCD solid-state imaging device 116.
[0034]
Thus, the rear group lenses 112 to 115 for forming the subject image on the imaging surface of the solid-state imaging device 116 are not provided in the thickness direction of the camera body 101, but are provided side by side in the height direction of the camera body 101. Therefore, the thickness of the camera body 101 can be reduced.
[0035]
Here, the configuration of the lens driving device of the present invention will be described with reference to FIG.
[0036]
The lens driving device 11 includes a lens holding frame 113a, 114a, a cam follower 113b, 114b provided in the lens holding frame 113a, 114a, a cam plate 117, and cam grooves 117a, 117b and a drive groove 117c provided in the cam plate 117. Become.
[0037]
The camera according to the present embodiment includes four lenses, and the lenses 112 to 115 are fitted into the lens holding frames 112a to 115a, respectively. Two of the lenses 112 to 115 are movable by the lens driving device 11. The cam followers 113b and 114b of the lens frames 113a and 114a into which the respective lenses are fitted are engaged with the cam grooves 117a and 117b of the cam plate 117, respectively. When a driving force is applied to the cam plate 117 by the driving pins 118b and 119b engaged with the driving groove 117c of the cam plate 117, the lens holding frames 113a and 113a engaged with the cam grooves 117a and 117b of the cam plate 117, respectively. The lenses 113 and 114 move together with the cam followers 113b and 114b of the 114a.
[0038]
The cam plate 117 is provided beside the four lenses 112 to 115, and a driving groove 117c is provided at an end of the cam plate 117. The drive groove 117c is formed so as to draw a sine wave, and the drive pins 118b and 119b are engaged with the groove 117c so as to draw a sine wave.
[0039]
When the zoom switch 103 (see FIG. 1) is operated, the distance between the four lenses is adjusted by moving these lenses 113 and 114 to adjust the optical zoom, and the release button 102 (see FIG. 1) is pressed. When done, the focal length is adjusted automatically.
[0040]
FIG. 2 is an enlarged view showing the configuration on the driving side of the lens driving device shown in FIG.
[0041]
FIG. 2A is an enlarged view of the cam plate 117, and FIG. 2B is a diagram showing a driving member including piezoelectric elements 118 and 119, rods 118a and 119a, and driving pins 118b and 119b. In FIG. 2, the arrow in the drawing indicates that the cam plate 117 moves in a direction opposite to the direction in which the drive pins 118b and 119b move. Arrows in the drawing also indicate whether the piezoelectric elements 118 and 119 are in the extending direction or the contracting direction.
[0042]
As shown in FIG. 2B, the drive pins 118b and 119b are fixedly mounted at the distal ends of the rods 118a and 119a so as to enter the drive grooves 117c of the cam plate 117, respectively. , 119b are fixed to the ends of the piezoelectric elements 118, 119, respectively. The ends 118c and 119c opposite to the ends are fixed to the camera body 101, respectively. Terminals for inputting electric signals are provided at the ends 118c and 119c on the side fixed to the camera body, and a voltage is externally applied to these terminals. Therefore, when the thickness of each of the piezoelectric elements 118 and 119 changes according to the change in the voltage applied from the outside, the change in the thickness is transmitted to the drive pins 118b and 119b fixed to the distal ends of the rods 118a and 119b. The drive pins 118b and 119b move according to the change in the thickness of the piezoelectric elements 118 and 119, respectively. In FIG. 2, it is indicated by arrows in the drawing that both piezoelectric elements are in the extending direction. The drive pins 118b and 119b that move in accordance with the change in the thickness of the piezoelectric elements 118 and 119 are respectively engaged with grooves 117c that draw a sine waveform, and the respective drive pins 118b and 119b have the sine wave shape. It is guided and moved by the groove 117c. Then, while the change in the thickness of each of the piezoelectric elements 118 and 119 makes one reciprocation, the groove corresponding to one cycle of the sine waveform is guided and moves. Therefore, if the pitch of the groove 117c having a sine wave shape is known, the position can be easily controlled by controlling the magnitude of the voltage applied to each of the piezoelectric elements 118 and 119 by a control unit (not shown). It is. In addition, since the control unit detects the setting status of the zoom switch 103 and the pressing status of the release button 102, if a voltage is applied to the piezoelectric elements 118 and 119 in accordance with the setting status to change the thickness, The driving force is transmitted to the cam followers 113b and 114b provided on the lens holding frames 113a and 114a, and the two lenses 113 and 114 move.
[0043]
In the lens driving device 11 of the present embodiment, when one of the two driving pins 118b and 119b approaches the peak 1171c or the valley 1172c of the groove 117c having a sine waveform, the peak 1171c or The other drive pin is provided so that a drive force over the valley 1172c can be given by the other drive pin 119b. In other words, the two drive pins 118b and 119b are arranged with their phases shifted from each other so as not to be simultaneously arranged at positions such as the peaks 1171c and 1173c or the peaks 1171c and the valleys 1174c of the groove 117c having a sine wave shape. I have. In this way, when one driving pin 118b is located at the position of the groove peak 1171c having a sinusoidal waveform and the moving direction cannot be determined according to the change in the thickness of the piezoelectric element 118c, the direction of movement by the other driving pin 119b is determined. A driving force can be applied, and it is clearly shown that the driving pin 118c moves in the direction of the valley 1172c when the driving pin 118c is at the peak 1171c of the groove 117c having a sine wave shape, and the driving pin 118c is stuck at the peak 1171c. It will not be.
[0044]
FIG. 3 is a diagram showing the operation principle on the driving side of the lens driving device of the present invention.
[0045]
FIG. 3A is a diagram showing a situation when one drive pin 118b approaches a peak 1171c, and FIG. 3B shows a situation when the drive pin 118b climbs over the peak 1171c. FIG.
[0046]
FIG. 3A shows a state in which both the piezoelectric elements 118 and 119 are controlled to extend, and the respective drive pins 118b and 119b move along the drive grooves 117c. In the figure, when the drive pins 118b and 119b move to the right, the cam plate 117 is driven in the opposite direction.
[0047]
When one of the drive pins 118b reaches the peak 1171c, the piezoelectric element 118 cannot be moved along the groove 117c even if the piezoelectric element 118 is further extended. Therefore, control is performed to change the amount of change in the voltage value and to contract the piezoelectric element 118. ing. At this time, a voltage change is applied to the other drive pin 119b in the direction in which the piezoelectric element extends, and the voltage is controlled, and the direction in which the drive pin 119b moves is determined. Therefore, when one of the drive pins 118b reaches the peak 1171c, control is performed to contract the piezoelectric element 118 so that the drive pin 118b moves the drive groove 117c rightward in the drawing by both forces.
[0048]
In this way, when one is likely to be stuck, the other assists and applies a driving force to the cam plate, so that the lens can be driven smoothly.
[0049]
FIG. 4 is a view showing another embodiment of the lens driving device of the present invention.
[0050]
As shown in FIG. 4, in addition to the cam grooves 117a and 117b, a drive groove 117d that draws a rectangular wave is provided.
[0051]
FIG. 5 is a diagram for explaining an operation state when the driving side of the lens driving device is configured using the cam plate shown in FIG.
[0052]
A situation is shown in which a common drive pin 118d for receiving a change in the thickness of the two piezoelectric elements has entered the groove 117d having the shape of a rectangular wave. Unlike FIG. 4, a common drive pin 118d is engaged with a drive groove 117d having a shape that draws a rectangular wave, and the common drive pin is fixed to both of the two rods 118a and 119a. When the rods 118a and 119a can apply a driving force from directions orthogonal to the common driving pin 118d, the direction in which the driving pin 118d moves is clearly shown. Piezoelectric elements 118 and 119 are fixed to opposite ends of the respective rods on which the common drive pins are fixed. The drive pin 118d moves along the horizontal portion 1171d of the groove 117d having a shape that draws a rectangular wave according to the thickness change of the one piezoelectric element 118, and the rectangular shape according to the change of the thickness of the other piezoelectric element 119. The drive pin 118d moves along the vertical portion 1172d of the waveform. If the distance for one cycle of the rectangular waveform is set to a predetermined value, the moving distance of the lens can be reliably grasped, and the finer the cycle of the rectangular waveform of the drive groove 117c, the finer the position can be controlled. Become.
[0053]
5 to 10 are diagrams illustrating the operation principle on the driving side of the lens driving device 11. Each figure shows how the drive pin is driven when the cam plate 117 is moved in the direction of the arrow in the figure.
[0054]
When the drive pin 118d is located at the position shown in FIG. 5, a voltage change is applied to one of the piezoelectric elements 118, and the thickness for the drive pin 118d at that position is given to the piezoelectric element 118.
[0055]
When the drive pin 118d is moved from the position shown in FIG. 5 to the position shown in FIG. 6, one of the piezoelectric elements 118 is controlled to contract in order to move the drive pin 118d in the horizontal portion 1173c of the drive groove 117d, as shown in FIG. Then, the drive pin 118d moves rightward in the figure. When the horizontal portion 1171d and the vertical portion 1172d of the drive groove 117d abut on the intersection, the other piezoelectric element 119 is controlled to shrink in order to move the drive pin in the vertical portion 1172d as shown in FIG. You. FIG. 8 shows a situation where the drive pin is moved and the drive pin hits a new crossing. This time, in order to further move the drive pin in the right direction in the figure, the one piezoelectric element 118 is controlled in a contracting direction as shown in FIG. 9, and the piezoelectric element is moved to a portion where the horizontal portion 1171d and the vertical portion 1172d of the drive groove 117d intersect. When the pin 118 is contracted and abutted, the other piezoelectric element 119 is controlled to extend in the direction as shown in FIG. The piezoelectric elements 118 and 119 are rotatably supported by a shaft, and the posture of the piezoelectric elements 118 and 119 changes according to the position of the driving pin by the rotation so that the piezoelectric element can be guided and moved by the driving groove 117d. It has become.
[0056]
A lens driving device capable of performing quiet and accurate positioning without noise by providing a driving groove in the cam plate 117 and moving a driving pin engaged with the driving groove in accordance with a change in the thickness of the piezoelectric element. Is realized.
[0057]
【The invention's effect】
As described above, it is possible to provide a lens driving device that can accurately position a lens without generating noise when driving a cam plate.
[Brief description of the drawings]
FIG. 1 illustrates an embodiment of a lens driving device according to the present invention, and is a diagram illustrating an external appearance of a camera including the lens driving device.
FIG. 2 is an enlarged view showing a configuration of a driving side of the lens driving device shown in FIG. 1 (c).
FIG. 3 is a diagram illustrating the operation principle of the lens driving device of the present invention.
FIG. 4 is a view showing another embodiment of the lens driving device of the present invention, showing an example in which the shape of a driving groove provided in a cam plate is changed.
FIG. 5 is a diagram illustrating an operation state when the driving side of the lens driving device is configured using the cam plate illustrated in FIG. 4;
FIG. 6 is a diagram illustrating an operation principle on a driving side of the lens driving device illustrated in FIG. 5;
FIG. 7 is a diagram illustrating an operation principle on a driving side of the lens driving device illustrated in FIG. 5;
8 is a diagram illustrating an operation principle on a driving side of the lens driving device illustrated in FIG. 5;
FIG. 9 is a diagram illustrating an operation principle on a driving side of the lens driving device illustrated in FIG. 5;
FIG. 10 is a diagram illustrating an operation principle on a driving side of the lens driving device illustrated in FIG. 5;
FIG. 11 is a diagram illustrating a relationship between a piezoelectric element and a moving body, for example, a lens frame;
FIG. 12 is a diagram showing a control voltage applied to a piezoelectric element.
FIG. 13 shows a lens driving device using the principle described with reference to FIGS. 11 and 12, which is an example in which positioning teeth are provided on a cam plate in order to increase positional accuracy.
[Explanation of symbols]
100 cameras
101 Objective lens
110 shooting optical system
111 reflector
112-115 lens
116 CCD solid-state imaging device
11 Lens drive
117 cam plate
117a Cam groove
117b Cam groove
117c Drive groove having a shape that draws a sine wave
1171c Yamabe
1172c Tanibe
1173c Yamabe
1174c Tanibe
117d Driving groove having a shape that draws a rectangular wave
1171d Horizontal section
1172d vertical part
118 Piezoelectric element
118a rod
118b drive pin
118d drive pin
119 Piezoelectric element
119a rod
119b Drive pin

Claims (3)

A lens holding frame for holding a lens with a cam follower,
A cam member having a cam groove in which the cam follower is fitted and moving the lens via a cam mechanism including the cam groove and the cam follower;
A drive source for driving the cam member,
The cam member has a driving groove for receiving a driving force of the driving source,
The drive source includes a piezoelectric element, a rod having one end fixed to the piezoelectric element, and transmitting a change in the thickness of the piezoelectric element, and a rod fixed to the rod and moving into the drive groove to move the rod to the cam member. A lens drive device comprising a plurality of drive members having a drive pin for transmitting. The drive groove is a groove having a shape extending in the moving direction of the cam member while drawing a sinusoidal waveform,
2. The lens driving device according to claim 1, wherein the plurality of driving members are arranged in a direction in which the driving groove extends, and are arranged at positions where the sinusoidal waveforms have different phases. 3. The drive groove is a groove having a shape extending in the moving direction of the cam member while drawing a rectangular waveform,
2. The device according to claim 1, wherein the plurality of driving members are rotatable and have a common driving pin inserted into the driving groove, and move the driving pins in mutually different directions. Lens driving device.

Images