JPH04212910A - Apparatus with built-in lens - Google Patents

Abstract

PURPOSE:To provide a compact and lightweight apparatus with a built-in lens in cameras, observatory apparatus or the like. CONSTITUTION:Constitution is made so that an intermittent carrying action may be performed by a guide member by integrally fitting two kinds of piezoelectric components 5a, 5c and 5b to guide members 3, 4 which are used to guide a lens holding frame 2, and making an alternate expansion contraction movements of the peizoelectric components. This constitution allows a lens shifting device to be extremely compact and lightweight since a conventional rotary type electromagnetic motor, a reduction mechanism of gears or the like are unnecessary.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a device with a built-in moving lens, such as a still camera, a video camera, or various observation devices, and more particularly to a lens moving device for the device. It is.

0002

[Prior Art] Conventionally, in the imaging systems of video cameras and photo cameras, focus adjustment and zooming are performed by moving the lens group of the imaging system back and forth in the optical axis direction, and the power to move this lens group is electromagnetic. It was obtained from the motor of the formula. As means for transmitting power from these electromagnetic motors to the lens group, there are methods that use a gear train to decelerate the rotation of the motor, convert it to high torque, and transmit it, and methods that use a timing belt or rubber belt to transmit the motor power. .

0003

However, in recent years, imaging devices such as video cameras and photographic cameras have become smaller and lighter, and conventional transmission mechanisms have been disadvantageous in reducing their size. In addition, miniaturization of electromagnetic motors is approaching its limit, which has become an obstacle to further miniaturization of devices.

[0004] It is therefore an object of the present invention to provide a device that is smaller and lighter than conventional devices, and in particular, the volume and weight of the lens moving device can be made much smaller than that of conventional devices. The objective is to provide a device with a built-in lens that can be used.

[0005]

[Means for Solving the Problems] A device with a built-in lens according to the present invention uses a piezoelectric element as a power source, and the piezoelectric element is integrally formed with a lens holding frame guide member, and the piezoelectric element is configured to extend and contract due to the expansion and contraction movement of the piezoelectric element. A lens holding frame feeding operation occurs in the guide member. The piezoelectric element is composed of a pair of two types of piezoelectric elements, an element having a piezoelectric longitudinal effect and an element having a piezoelectric shearing effect, and the guiding member is caused to move the lens holding frame by the alternating expansion and contraction action of each piezoelectric element. It is designed to cause

[0006]

[Operation] In the lens built-in device according to the present invention, two types of piezoelectric elements integrated with the lens holding frame guide member operate alternately to cause the guide member to move the lens holding frame, thereby causing the lens holding frame to move. Since the frame is fed, there is no need for conventional rotary electromagnetic motors, gears, etc. Therefore, it is possible to realize a device with a built-in lens that is smaller and lighter than conventional devices.

[0007]

Embodiment A first embodiment of the present invention will be described below.

FIG. 1 is a sectional view showing the structure of the present invention. In FIG. 1, 1 is a lens, and 2 is a lens frame for holding the lens 1. The lens frame 2 is guided and supported by two guide bars 3 and 4. The first guide bar 4 is fixed by a lens barrel 6, and the second guide bar 3 is integrally formed with piezoelectric elements 5a, 5b, and 5c. The piezoelectric elements 5a, 5b, 5c are cylindrical, and the guide bar 3 and the piezoelectric elements 5a, 5b, 5c are aligned on the same axis so as to form one rod-shaped body. It is fixed to the elements 5b and 5c by adhesive or the like. Note that the piezoelectric elements 5a and 5c at both ends are rotatably supported by the lens barrel 6. FIG. 2 shows a front view of the lens frame 2.

The lens frame 2 is ring-shaped so as to concentrically hold the lens 1, and is guided by a guide bar 4 through a groove 2b. Further, a sleeve 2a integrally formed 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 its surface, and the sleeve 2a is also threaded with the same shape, and the sleeve 2a is engaged with the thread of the guide bar 3. In the above configuration, when the guide bar 3 rotates forward, the lens frame 2 is moved to the left in FIG. When the guide bar 3 rotates in the opposite direction, the lens frame 2 also moves in the opposite direction.

FIG. 3 shows a guide bar 3 and piezoelectric elements 5a and 5b.
, 5c shows an enlarged view of the integrally formed member. The piezoelectric elements 5a and 5c are elements having a so-called piezoelectric longitudinal effect, which are polarized in the direction of the arrow in FIG. When a voltage is applied to the electrodes 5d, 5e, 5g, and 5h, the piezoelectric elements 5a, 5c expand and contract, changing their outer diameter and length. The piezoelectric element 5b has a cylindrical shape as shown in FIG.
It consists of four parts, and these four parts are polarized in the direction of the arrow shown in FIG. The piezoelectric element 5b is an element having a shearing effect, and therefore causes torsional deformation when a voltage is applied to the electrodes 5e and 5f.

3a and 3b in FIG. 3 are adhesive layers for fixing the piezoelectric elements 5b and 5c. 5i, 5j are electrodes 5d,
5h is a disc that does not come into direct contact with the lens barrel 6, and the discs 5i and 5j are coated with a surface treatment such as a fluororesin coating to reduce the coefficient of friction between them and the lens barrel 6. has been done.

Next, the operation of directly driving the lens frame 2 using these piezoelectric elements will be explained. FIG. 6 shows a diagram explaining these operations, and FIG. 7 shows voltage waveforms for driving these piezoelectric elements 5a, 5b, and 5c.

At time TO, piezoelectric elements 5a, 5b,
No voltage is applied to 5c, indicating the initial state. Next, between time TO and T1, a voltage is applied to the piezoelectric element 5a, the length of the piezoelectric element 5a is reduced, and the outer diameter thereof is increased. As a result, the outer peripheral surface of the piezoelectric element 5a is pressed against the lens barrel 6, making the element 5a and the guide bar 3 unrotatable, and the piezoelectric element 5a is fixed.

Next, between time T1 and T2, the piezoelectric element 5
a is held in the clamped state as it is, and a voltage is applied to the piezoelectric element 5b. Then, twisting occurs in the element 5b, and the piezoelectric element 5a is fixed, so that the guide bar 3 and the piezoelectric element 5c rotate. Next, between times T2 and T3, the piezoelectric element 5a is held fixed and the piezoelectric element 5b is held twisted, and when a voltage is applied to the piezoelectric element 5c, the piezoelectric element 5c becomes a mirror in the same manner as described above. It is fixed to the cylinder 6. Next, from time T3 to time T4, the voltage of the piezoelectric element 5a is lowered to return to the initial state. As a result, the element 5a is released from the clamped state and is rotatably supported by the lens barrel 6. Next, between times T4 and T5, the voltage of the piezoelectric element 5b is lowered to return to the initial state. At this time, the piezoelectric element 5c
is fixed, the guide bar 3 and piezoelectric element 5a rotate in the direction of the arrow in the figure. Next, between time T5 and T6,
Since the voltage of the piezoelectric element 5c is lowered and returned to the initial state, the piezoelectric elements 5a, 5b, and 5c also return to the initial state at time T0.

By repeating the voltage application cycle from time T0 to time T6 as described above, the guide bar 3 rotates intermittently, and as a result, the lens frame 2 is intermittently moved in the optical axis direction. In addition, when changing the lens frame feeding speed, it is sufficient to change the period from time T0 to T6. Furthermore, when the lens is to be sent in the opposite direction, a voltage that causes the piezoelectric element 5b to be twisted in the opposite direction may be applied from time T1 to T2. Detailed explanation will be omitted.

Next, a second embodiment will be explained.

FIG. 8 shows a cross-sectional view of the structure of the second embodiment. The basic configuration is the same as that of the first embodiment; 1 is a lens, 2 is a lens frame, 3 and 4 are guide bars, and the guide bar 4 is supported and fixed by a lens barrel 6. As the guide bar 3 rotates, the lens frame 2 moves in the optical axis direction. 7a, 7b
, 7c are piezoelectric elements, which are formed integrally with the guide bar 3. The piezoelectric elements 7a and 7c have a cylindrical shape as shown in FIG. 10, are polarized in the direction of the arrow shown in FIG. 11, and when a voltage is applied, transform from the shape shown by the solid line to the shape shown by the dotted line as shown in FIG. 12. do. FIG. 9 shows an enlarged sectional view of the piezoelectric elements 7a, 7b, 7c and the guide bar 3 of the second embodiment.

The piezoelectric elements 7a and 7c are engaged with cylinders 6a and 6b extending from the lens barrel 6 and are rotatably supported. The piezoelectric elements 7a and 7c are elements having a piezoelectric longitudinal effect, and when a voltage is applied to the electrodes 7d, 7e, 7g, and 7h, the voltage shown in FIG.
It transforms into the shape shown by the dotted line. Moreover, the piezoelectric element 7b is the same as the piezoelectric element 5b of the first embodiment, and the electrodes 7e, 7
When voltage is applied to f, twisting occurs.

Next, the movements of these piezoelectric elements and the waveforms of voltages applied to the elements will be explained with reference to FIGS. 13 and 14.

At time T0, piezoelectric elements 7a, 7b,
No voltage is applied to 7c and no deformation occurs in the element (initial state). Next, from time T0 to time T1, a voltage is applied to the piezoelectric element 7a, and the element 7a deforms into the shape shown by the dotted line in FIG. As a result, piezoelectric element 6a and piezoelectric element 7a
The inner diameter of the element 7a becomes smaller in the fitting relationship with the element 7a,
Since the inner periphery of the element 7a is pressed against the outer periphery of the element 6a, the element 7a becomes unrotatable, and the piezoelectric element 7a
It is fixed at a. Next, between times T1 and T2, a voltage is applied to the piezoelectric element 7b while the piezoelectric element 7a remains fixed, causing twisting in the direction of the arrow, and as a result, the guide bar 3 and the piezoelectric element 7c rotate. . Next, from time T2 to T3
During this period, a voltage is applied to the piezoelectric element 7c while the piezoelectric elements 7a and 7b remain as they are. Then, the piezoelectric element 7c is fixed to the piezoelectric element 6b in the same manner as described above. Next, between time T3 and T4, the piezoelectric elements 7b and 7c remain as they are, and the voltage of the piezoelectric element 7a is lowered to the same potential as COM, which brings it into the initial state.
Piezoelectric elements 6a and 7a are again rotatably supported. Next, between time T4 and T5, when the voltage of the piezoelectric element 7b is lowered to COM while the piezoelectric element 7c remains unchanged, the piezoelectric element 7c remains fixed, so that the guide bar 3 and the piezoelectric element 7a move in the direction of the arrow in the figure. Rotate. Next time T5
to T6, the piezoelectric elements 7a and 7b remain as they are, and when the voltage of the piezoelectric element 7c is lowered to COM, the piezoelectric element 7c is rotatably supported by the piezoelectric element 6b and returns to the initial state as described above. By repeating this series of cycles T0 to T6, the guide bar 3 rotates intermittently, and as a result, the lens frame 2 also moves intermittently in the optical axis direction. In addition,
When changing the speed, it is sufficient to change the cycle of T0 to T6. Furthermore, when feeding in the reverse direction, by reversing the voltage applied to the piezoelectric element 7b between times T1 and T2, it is possible to cause the piezoelectric element 7b to twist in the opposite direction, thus making it possible to feed in the reverse direction. .

[0021]

[Effects of the Invention] As explained above, the lens built-in device of the present invention can achieve the following effects.

(i) Since conventional speed reduction mechanisms such as gear boxes and belts are not required, the volume and weight of the lens drive device can be significantly reduced, and devices with built-in lenses such as cameras can be made smaller and lighter. can be realized,
Furthermore, manufacturing costs can also be reduced.

(ii) By using a piezoelectric element in place of a conventional electromagnetic motor, the electric power source can be made smaller, and a lens driving device that is quieter than the conventional electromagnetic motor can be realized.

(iii) Since minute intermittent driving of the lens frame becomes possible, open-loop control is possible in the same way as when using a step motor, and furthermore, a lens drive control system suitable for digital control can be realized.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a lens moving device in a first embodiment of a lens-equipped device of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG. 1;

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

FIG. 4 is a diagram showing the shape of a piezoelectric element 5b.

FIG. 5 is a diagram showing the force generated on the piezoelectric element 5b.

FIG. 6 is an explanatory diagram of the motion that occurs in the composite body of the guide bar 3 and piezoelectric elements 5a to 5c.

FIG. 7 is a diagram illustrating voltage application to a piezoelectric element.

FIG. 8 is a schematic diagram of the structure of a lens moving device according to a second embodiment of the present invention.

FIG. 9 is an enlarged view of a part of FIG. 8 and a diagram showing electrical connections to the piezoelectric element.

FIG. 10 is an external view of piezoelectric elements 7a and 7c.

FIG. 11 is a diagram showing forces generated in piezoelectric elements 7a and 7c.

FIG. 12 is a diagram showing a deformed state of a piezoelectric element.

FIG. 13 is an explanatory diagram of the motion that occurs in the composite body of the guide bar 3 and piezoelectric elements 7a to 7c.

FIG. 14 is a diagram showing voltage application cycles to piezoelectric elements 7a to 7c.

[Explanation of sign]

1...Lens
2... Lens frame 3, 4... Guide bar
6... Lens barrels 7a, 7b, 7c, 5a, 5b,
5c...Piezoelectric elements 7d, 7e, 7f, 7g, 7h, 7i,
5d, 5e, 5f, 5g, 5h, 5i...electrodes

Claims (1)

[Claims] Claim 1: A device with a built-in lens having a guide member for moving a lens holding member along an optical axis, which is integrated with the guide member arranged in series on the same axis as the guide member. It has two types of piezoelectric elements, the first of the piezoelectric elements is an element having a piezoelectric longitudinal effect, and the second of the piezoelectric elements is an element having a piezoelectric shear effect. A device with a built-in lens.