JP2760660B2 - Driving device and equipment with built-in lens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device and a device with a built-in moving lens such as a still camera, a video camera or various observation devices.

[0002]

2. Description of the Related Art Conventionally, focus adjustment and zooming in an image pickup system of a video camera and a photographic camera are performed by moving a lens group of the image pickup system back and forth in the optical axis direction. From the motor. Means for transmitting power from these electromagnetic motors to the lens group include those that reduce the rotation of the motor by a gear train and convert it to high torque and transmit it, and those that transmit the power of the motor by a timing belt or rubber belt. .

[0003]

However, in recent years,
The size and weight of imaging devices such as video cameras and photographic cameras have been reduced, and conventional transmission mechanisms have been disadvantageous in terms of size reduction. Also, the miniaturization of the electromagnetic motor is approaching its limit, which has been an obstacle to further miniaturization of the device. Therefore, the object of the present invention is to reduce the size and weight of the conventional equipment.
The present invention provides a drive device and a device with a built-in lens that can be achieved , and can be used particularly as a lens moving device or the like.
An object of the present invention is to provide a drive device and a device with a built-in lens which can make the volume and weight of the drive device much smaller than those of the related art.

[0004]

In order to achieve the above object, a driving device according to a first aspect of the present invention provides a piezoelectric longitudinal effect.
And a second piezoelectric element exhibiting a piezoelectric shear effect.
A drive device in which electric elements are arranged in series, wherein the piezoelectric vertical
The first piezoelectric element or the second piezoelectric element based on the effect.
While the element is pressed against the end of the rod-shaped member, the piezoelectric shear
Screw in a direction in said second piezoelectric element based on the effect
Causing the rod-shaped member to move in the direction
After the first piezoelectric element or the second pressure
Release the press-contact state of the electric element and check whether the end of the rod-shaped member
The second piezoelectric element in the state separated from
To repeat the action that causes the torsional movement in the direction
Therefore, the rod member is rotated in the direction . In order to achieve the above object, a driving device according to a second aspect of the present invention is directed to the driving device described above.
The rod-shaped member is a member having a threaded surface.
It is characterized by the following. To achieve the above object, a lens device housing of the third invention of the present application, Len
Lens holding member and a rod screwed to the lens holding member
A lens-containing device having a rod-shaped member,
The first piezoelectric element having the piezoelectric longitudinal effect near the end of the material and the pressure
A second piezoelectric element having an electroshear effect is arranged in series,
The first piezoelectric element or the first piezoelectric element based on the piezoelectric longitudinal effect
In a state where the second piezoelectric element is pressed against the end of the rod-shaped member,
The second piezoelectric element based on the piezoelectric shear effect
Said rod-shaped member by causing a torsional movement in
After the first piezoelectric element or the front
The pressure contact state of the second piezoelectric element is released and the rod-shaped portion is released.
The second piezoelectric element is separated from the end of the material by the second piezoelectric element.
Repeat the operation to generate a twisting motion in the direction opposite to the direction
By rotating the rod-shaped member in the direction,
The lens holding member is moved .

[0005]

By applying a voltage in a predetermined pattern alternately to the two kinds of piezoelectric elements in a predetermined cycle, a step-wise inching rotation is generated in the lens holding frame guide member and the feed member. It is moved stepwise along the optical axis direction.

According to the present invention, it is possible to realize a lens moving device which does not require a conventional rotary electromagnetic motor, gears, electric belts, and the like, and therefore, it is possible to realize a lighter and smaller lens-incorporated device than before.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of the first embodiment. 1 is a lens, and 2 is a lens frame for holding the lens 1. The lens frame 2 is supported and guided by guide bars 3 and 4. The guide bars 3 and 4 are supported by a lens barrel 6 surrounding the lens frame 2. The guide bar 4 is fixed by a lens barrel 6,
Are supported rotatably about a center line 7 shown in FIG. FIG. 2 shows a front view of the lens frame 2. The lens frame 2 has a ring shape so as to hold the lens 1 on a concentric circle, and is guided by a guide bar 4 by a groove 2b. A sleeve 2 a formed integrally with the lens frame 2 is guided and supported by a guide bar 3. The guide bar 3 is threaded in a predetermined range on the surface, and a thread of the same shape is also threaded on the sleeve 2a so as to mesh with the thread of the guide bar 3. Therefore, when the guide bar 3 rotates, the lens frame 2 is moved along the optical axis in FIG. When the guide bar 3 rotates in the reverse direction, the lens frame 2 also moves in the opposite direction.

In FIG. 1, reference numeral 5 denotes a piezoelectric element serving as a power source. FIG. 3 shows an enlarged sectional view of the piezoelectric element 5 and the guide bar 3 and a configuration of the piezoelectric element 5. The piezoelectric element 5 is 2 of 5a and 5b.
It is composed of various kinds of piezoelectric elements. Reference numeral 5a denotes a piezoelectric element having a piezoelectric longitudinal effect, which has a cylindrical shape shown in FIG.
The piezoelectric element 5a is polarized in the direction of the arrow shown in FIG. 5, and is deformed from a solid line to a dotted line as shown in FIG. 6 when a voltage is applied to the electrodes 5c and 5d. The piezoelectric element 5b is a piezoelectric element having a piezoelectric shear effect, and has a cylindrical shape as shown in FIG. The piezoelectric element 5b is composed of four parts, each of which has been subjected to polarization processing in the direction of the arrow shown in FIG. Accordingly, when a voltage is applied to the electrodes 5c and 5f, the piezoelectric element 5b twists in the circumferential direction as shown in FIG. Power is transmitted to the guide bar 3 by combining these two types of piezoelectric elements. A series of these operations will be described below.

FIG. 9 is a diagram for explaining the operation of the piezoelectric element 5, and FIG. 10 shows waveforms of voltages to be applied to the piezoelectric elements 5a and 5b. At time T0, the piezoelectric elements 5a, 5
Since no voltage is applied to b, an initial state in which the piezoelectric element 5a does not contact the guide bar 3 is set.

Next, a voltage is applied to the piezoelectric element 5b from T0 to T1, and the element 5b is twisted in the direction of the arrow in the figure. At this time, since the guide bar 3 and the element 5b have a small gap (for example, several μm), the torsional movement of the element 5b is not transmitted to the guide bar 3.

Next, during a period from T1 to T2, a state in which a voltage is applied to the piezoelectric element 5b is maintained, and a voltage is also applied to the piezoelectric element 5a. As a result, the piezoelectric element 5a is
As shown in the dotted line, the inner diameter of the piezoelectric element 5 is reduced while the inner diameter is reduced.
The inner peripheral surface of a is pressed against, and the guide bar 3 is clamped by the piezoelectric element 5a.

Next, from T2 to T4, the element 5b has T
A voltage opposite to that of T1 is applied from 0 to T1, and the element 5b is twisted in the direction of the arrow. As a result, the guide bar 3 also rotates in the torsion direction of the piezoelectric element 5b. Next, from T4 to T
By stopping the application of voltage to the piezoelectric element 5a during the period 5, the piezoelectric element 5a returns to its original shape, so that the element 5a
The guide bar 3 is no longer in contact with the inner peripheral surface of the piezoelectric element 5b, but the same voltage as that of T3 is applied to the piezoelectric element 5b. Next, while no voltage is applied to the piezoelectric element 5a during the period from T5 to T6, a voltage is applied to the piezoelectric element 5b in the opposite direction from that at the time from T2 to T4, so that both the piezoelectric elements 5a and 5b return to the initial state. . By repeating the cycle from T0 to T6 in this manner, the guide bar 3 rotates intermittently, and as a result, the lens frame 2 is intermittently fed in the optical axis direction. When the lens frame 2 is sent in the reverse direction, it is clear that the voltage application cycle should be reversed from T6 to T0. Also, the speed can be changed by changing the cycle period. Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 11 shows the configuration of the second embodiment. The basic configuration is the same as that of the first embodiment. When the guide bar 7 rotates, the lens frame 2 moves in the optical axis direction.

Next, the operation of transmitting power from the piezoelectric element 8 to the guide bar 7 will be described below.

FIG. 12 is an enlarged sectional view of the guide bar 7 and the piezoelectric element 8 of this embodiment. The piezoelectric element 8 is composed of 2 of 8a and 8b.
It is composed of various kinds of piezoelectric elements. The piezoelectric element 8a is a piezoelectric element having a piezoelectric shearing effect, and is the same as the piezoelectric element 5b of the first embodiment. The piezoelectric element 8b is a piezoelectric element having a piezoelectric longitudinal effect, has a columnar shape, is polarized in the direction of the arrow in the figure, and expands and contracts when a voltage is applied to the electrodes 8e and 8f. It is a board. As shown in FIG. 12, the guide bar 7 and the piezoelectric element 8
Have a small gap and are not in contact with no voltage. FIG. 13 shows the movement of the piezoelectric element and FIG. 14 shows the waveform of the voltage applied to the piezoelectric element. As shown in FIG. 13, in the initial state T0, no voltage is applied to the piezoelectric elements 8a and 8b. From T0 to T1, the piezoelectric element 8a
Voltage is applied, twisting occurs in the direction of the arrow in the figure. At this time, no voltage is applied to the piezoelectric element 8b. From T1 to T2, the same voltage as that at time T1 is applied to the piezoelectric element 8a and the voltage is applied to the piezoelectric element 8b, so that the friction plate 8c extends and the guide bar 7 comes into contact. From time T2 to T4, the same voltage is applied to the piezoelectric element 8b as at time T2, while a voltage is applied to the piezoelectric element 8a in a direction opposite to that in the case of T0 to T1, so that twisting occurs.
As a result, the guide bar 7 also rotates in the same direction.

From T4 to T5, the voltage applied to the piezoelectric element 8b becomes the same voltage as COM, and the piezoelectric element 8b returns from its elongation to its original state. At this time, the same voltage as that at the time T4 is applied to the piezoelectric element 8a. From T5 to T6, the applied voltage to the piezoelectric element 8b is the same as that at the time T5, and the applied voltage to the piezoelectric element 8a is returned to the same voltage as COM. As a result, both the piezoelectric elements 8a and 8b return to the initial state (the state at time T0).

By repeating the above cycle, the guide bar 7 rotates intermittently, and as a result, the lens frame 2 is intermittently fed in the optical axis direction. When the lens frame 2 is sent in the reverse direction, the voltage application cycle for the piezoelectric element is set to T.
What is necessary is just to reverse from 6 to T0. When changing the speed, the cycle of the cycle may be changed.

[0018]

As described above , according to the present invention ,
The following effects can be obtained.

(I) Since the conventional gearbox, belt, and other deceleration mechanisms are not required, the volume and weight of the lens driving device can be significantly reduced, and the size and weight of the device with a built-in lens such as a camera can be reduced. It can be realized, and the manufacturing cost can be reduced.

(Ii) By using a piezoelectric element instead of a conventional electromagnetic motor, a power source can be reduced in size, and a lens drive device that is quieter than a conventional electromagnetic motor can be realized.

(Iii) Since minute intermittent driving of the lens frame is possible, open-loop control can be performed as in the case of using a step motor, and a lens drive control system suitable for digital control can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic view of a lens moving device in a first embodiment of a device with a built-in lens of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is an enlarged view of a part of FIG. 1 and a diagram showing electrical connection to a piezoelectric element.

FIG. 4 is a diagram showing a shape of a piezoelectric element 5a when it is not deformed.

FIG. 5 is a diagram showing a force generated in a piezoelectric element 5a.

FIG. 6 is a diagram illustrating a deformed state of a piezoelectric element 5a.

FIG. 7 is a view showing a shape of a piezoelectric element 5b when it is not deformed.

FIG. 8 is a diagram showing a force and deformation generated in a piezoelectric element 5b.

FIG. 9 is a diagram showing an operation cycle of the piezoelectric elements 5a and 5b with respect to the guide bar 3.

FIG. 10 is a diagram showing voltage waveforms applied to piezoelectric elements 5a and 5b in FIG.

FIG. 11 is a schematic view of a lens moving device according to a second embodiment of the present invention.

12 is an enlarged view of a guide bar 7 and a piezoelectric element in the apparatus of FIG. 11, and a diagram showing electrical connection to the piezoelectric element.

13 is a diagram showing an operation cycle of the piezoelectric element with respect to the guide bar 7 in the embodiment of FIG.

FIG. 14 shows the piezoelectric elements 8a and 8 in the embodiment of FIG.
The figure which showed the waveform of the applied voltage with respect to b.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Lens 2 ... Lens frame 3, 4, 7 ... Guide bar 6 ... Barrel 5a, 5b, 8a, 8b ... Piezoelectric element 5c, 5d, 5e, 8d, 8e, 8f ... Electrode

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Junichi Murakami 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-62-101921 (JP, A) JP-A-62 JP-A-296109 (JP, A) JP-A-1-197707 (JP, A) JP-A-63-135908 (JP, A) JP-A-62-102212 (JP, A) JP-A-60-4910 (JP, A) (58) Fields surveyed (Int.Cl. ⁶ , DB name) G02B 7/02 G02B 7/04

Claims (3)

(57) [Claims] 1. A driving the second piezoelectric element showing a first piezoelectric element and the piezoelectric shear effect showing a pressure Dentate effect arranged in series
An apparatus, wherein the first pressure is based on the piezoelectric longitudinal effect.
An electric element or the second piezoelectric element is pressed against the end of the rod-shaped member.
The second pressure based on the piezoelectric shear effect
By causing the element to twist in one direction.
After the rod member is rotated in the direction,
Release the pressure contact state of the piezoelectric element or the second piezoelectric element.
In the state of being separated from the end of the rod-shaped member.
Causes a torsional motion in the opposite direction to the above direction.
By repeating the operation to make the rod-shaped member
A driving device characterized by rotating in a direction . 2. The bar is threaded on its surface.
The driving device according to claim 1, wherein the driving device is a member . 3. A lens holding member, comprising: a lens holding member;
For devices with built-in lenses that have a rod-shaped member
Has a piezoelectric longitudinal effect near the end of the rod-shaped member.
First piezoelectric element and second piezoelectric element having piezoelectric shear effect
Are arranged in series, and the first
The piezoelectric element or the second piezoelectric element at the end of the rod-shaped member.
In the pressed state, the second
Causing the piezoelectric element to twist in a certain direction
After rotating the rod-shaped member in the direction by the
The pressure contact state of the first piezoelectric element or the second piezoelectric element
Release and separate from the end of the rod-shaped member
2 generates a torsional motion in the direction opposite to the above direction.
The rod-shaped member is moved forward by repeating the
To rotate the lens holding member.
And a device with a built- in lens.