JPH04212909A - Apparatus with built-in lens - Google Patents

Abstract

PURPOSE:To provide an apparatus with a built-in lens which is furnished with a compact, lightweight lens shifting device inexpensive in manufacturing-cost. CONSTITUTION:There are comprised three piezoelectric components which achieve clamp/unclamp action consecutively relative to a lens frame guide member in an integrated manner with a lens frame 2 to make a rotary power mechanism of a convention electromagnetic motor, gears or the like unnecessary. Thus, absence of the conventional rotary power mechanism enables production of a lightweight, compact image pickup apparatus and an observatory apparatus inexpensive in manufacturing-cost.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a lens built-in device having a built-in movable 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 two methods: one in which the rotation of the motor is decelerated by a gear train, converted into high torque, and transmitted, and the other in which the power of the motor is transmitted by a timing belt or a rubber belt. .

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 employs a piezoelectric element as a power source, and the piezoelectric element is integrated with a lens holding frame, and the piezoelectric element is connected to a lens holding frame guide member. The lens holding frame is moved in an inching manner along the optical axis by alternately performing clamping and unclamping operations.

[0006]

[Operation] In the lens moving device for a device with a built-in lens according to the present invention, there is no rotary electromagnetic motor, and the lens holding frame itself inchingly moves parallel to the optical axis.

[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. 1 is a lens, and 2 is a lens frame that holds and fixes the lens 1 on a concentric circle. Guide bars 3 and 4 serve as guides for the lens frame 2 to move in the optical axis direction. A lens barrel 6 holds and fixes the guide bars 3 and 4. 5 is a piezoelectric element. FIG. 2 shows a front view of the lens frame 2. As shown in the figure, the lens frame 2 and the piezoelectric element 5 are integrally formed using an adhesive 2a or the like.

FIG. 3 shows a configuration diagram of the piezoelectric element 5 described above.

5a, 5b, and 5c are cylindrical piezoelectric elements that are integrally formed. When voltage is applied to electrodes 5d and 5e, piezoelectric element 5a expands and contracts; when voltage is applied to electrodes 5f and 5g, 5f expands and contracts; and when voltage is applied to electrodes 5h and 5i, piezoelectric element 5c expands and contracts.

Next, the movement of the piezoelectric element 5 will be explained based on FIG. FIG. 5 shows the waveforms of voltages V1, V2, and V3 applied to each voltage element 5a, 5b, and 5c.

At time T0, no voltage is applied to 5a, 5b, and 5c, and they are in their initial state. Time T0
At T1, a voltage is applied to the piezoelectric element 5a and it contracts. At the same time, the inner diameter is also reduced, the guide bar 3 is clamped, and the piezoelectric element 5 is fixed to the guide bar 3. Next, from time T1 to time T2, piezoelectric element 5a remains as it is, and a voltage is applied to 5b, causing piezoelectric element 5b to expand.

Next, between T2 and T3, the piezoelectric elements 5a and 5
A voltage is applied to the piezoelectric element 5c while b remains unchanged. Then, the piezoelectric element 5c contracts and clamps the guide bar 3. Next, from T3 to T4, the piezoelectric elements 5b and 5c remain as they are, and the voltage of the piezoelectric element 5a is returned to its original value. Next, between T4 and T5, the piezoelectric elements 5a and 5c remain as they are, and the piezoelectric element 5
Return the voltage at b. Next, between T5 and T6, the voltage of the piezoelectric element 5c is returned to its original state while the piezoelectric elements 5a and 5b remain as they are. As a result, the piezoelectric element 5 moves in the direction of the arrow in the figure.

By repeating the above voltage application cycle from T0 to T6, the piezoelectric element 5 moves intermittently, and as a result, the lens frame 2 formed integrally with the piezoelectric element 5 moves intermittently.
And the lens 1 also moves in the optical axis direction.

When changing the direction of movement, the period T0→T6 may be reversed to T6→T0. Also, when changing the moving speed, the cycle can be changed. Note that even quieter driving is possible by increasing the driving cycle of the piezoelectric element to the ultrasonic range.

[0016]

As explained above, the lens built-in device according to the present invention can achieve the following effects.

(i) Since conventional speed reduction mechanisms such as gearboxes and belts are not required, the volume and weight of the lens drive device can be greatly reduced, and devices with built-in lenses such as cameras can be made smaller and lighter. This also makes it possible to reduce manufacturing costs.

(ii) By using a piezoelectric element instead of a conventional electromagnetic motor, the power source can be downsized, and a lens driving device that is quieter than a 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 for a device with a built-in lens according to 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 operation of the piezoelectric element 5.

FIG. 5 is a diagram showing a voltage cycle applied to the piezoelectric element 5.

[Explanation of symbols]

1...Lens 2...Lens frame 3, 4...Guide bar 5...Piezoelectric element 5a, 5b, 5c...piezoelectric element

Claims (1)

[Claims] 1. In a device with a built-in lens having a guide member for moving a lens holding member along an optical axis, a power generating means for inching along the optical axis while engaging with the guide member. is formed integrally with the lens holding member, and the power generating means is formed of three piezoelectric bodies having a piezoelectric longitudinal effect.