JPH04100013A - Piezoelectric actuator - Google Patents

Abstract

PURPOSE:To effectively absorb a chattering amplitude and to improve positioning accuracy by providing a piezoelectric plate with a mass body which has specific mass for attenuating the amplitude of chattering generated at the time of a collision against a stopper. CONSTITUTION:The load mass body 21 is installed on the piezoelectric plate 1 of the piezoelectric actuator to greatly absorb the chattering generated by the collision of the piezoelectric plate 1 against the stopper 9. The positioning accuracy of the piezoelectric plate 1 which uses the stopper 9 is increased to enable high-accuracy, fast switching. The mass and fitting position are determined by an experiment according to the chattering amplitude and it is most effective to arrange the mass body 21 at the upper end of the piezoelectric plate 1.

Description

[Detailed Description of the Invention] [Summary] Regarding a piezoelectric actuator having a piezoelectric plate that is displaced in proportion to the magnitude of an applied voltage, a chattering amplitude can be effectively absorbed when the piezoelectric plate is positioned at a predetermined position with a stopper. A piezoelectric actuator is provided with a piezoelectric plate on both sides of which is bent and displaced in proportion to an applied voltage, and has grooves for regulating the displacement position of the piezoelectric plate. A mass body having a predetermined mass is provided to attenuate the chattering amplitude generated upon collision with the stopper.

[Industrial Application Field] The present invention relates to a piezoelectric actuator that can provide high-speed, highly accurate displacement.

In recent years, there has been an increasing need for actuators that can change positions at high speed and with high precision.In particular, when piezoelectric actuators are used as optical switches (optical switches compatible with multi-optical fibers) that change optical paths in optical LAN, etc., distances of several hundred microns in 10n+sec have increased. It is required to convert the position with a positional accuracy of about ±1-.

[Conventional technology]

FIG. 7 is a schematic perspective view of an optical switch using a conventional ceramic piezoelectric plate.

In this figure, 1 is a ceramic piezoelectric plate, 3 is a movable optical fiber, 5.7 is a fixed optical fiber, and 9 is a stopper.

The movable optical fiber 9 is glued to the upper end of the ceramic piezoelectric plate, and the ceramic piezoelectric plate 1 is mechanically fixed to the base 11 at the base, and the fixed optical fibers 11 and 12 are fixed by a support (not shown). be done.

electrodes 13A formed on both sides of the ceramic piezoelectric plate 1;
By applying a voltage to 13B (only 13A is shown), the upper end of the piezoelectric plate 1 is bent in the direction of the arrow, moving the movable optical fiber 3 in the same direction, and changing the optical axis of the movable optical fiber 9.
Align it with the optical axis of one of the fixed optical fibers 5.7,
The two are optically coupled and the optical path is switched.

[Problems to be Solved by the Invention] However, the conventional piezoelectric actuator as described above can only be used at low speeds, and there are problems that need to be solved when it is used as an optical switch that requires high speed and high precision. There are many left.

One of these is the chattering (vibration) of a piezoelectric plate. That is, although the displacement position or the initial position of the piezoelectric plate 1 is determined by contacting the stopper 9, the piezoelectric plate chattering occurs during the collision, making it impossible to perform high-speed positioning.

An object of the present invention is to improve positioning accuracy by effectively absorbing chattering amplitude when positioning a piezoelectric plate at a predetermined position using a stopper. Thereby, the piezoelectric actuator of the present invention can be applied as a high-speed actuator such as an optical switch.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a piezoelectric actuator in which stoppers are provided on both sides of a piezoelectric plate that bends and displaces in proportion to an applied voltage, for regulating the displacement position of the piezoelectric plate, the piezoelectric actuator comprising: The structure is characterized in that a mass body having a predetermined mass is provided to attenuate the chattering amplitude generated upon collision with the stopper.

The piezoelectric plate is preferably formed of LiNbO3 with inverted polarization.

A piezoelectric actuator for an optical switch according to the present invention includes a piezoelectric plate that bends and displaces in proportion to an applied voltage, stoppers provided on both sides of the piezoelectric plate to regulate the displacement position of the piezoelectric plate, and stoppers provided on the piezoelectric plate. A mass body having a predetermined mass that attenuates the chattering amplitude generated when the piezoelectric plate collides with the stopper, at least one movable optical fiber supported at the upper end of the piezoelectric plate so as to be displaceable together with the mass body, and a movable optical fiber facing the movable optical fiber. and at least one fixed optical fiber arranged on one example of the piezoelectric plate and optically connected to the movable optical fiber in response to displacement of the piezoelectric plate.

[For production]

Stoppers installed on both sides of the piezoelectric plate enable high-speed positioning, but at this time, a load mass is installed on the piezoelectric plate, which greatly absorbs chattering caused by collision between the stopper and the piezoelectric plate during high-speed switching. can.

LiNb0. polarization inverted piezoelectric plate. By forming this, displacement hysteresis is eliminated and positioning with higher precision becomes possible.

If this actuator is applied to a mechanical optical switch D compatible with multimode optical fibers, a high-speed optical switch that is resistant to external vibrations can be obtained.

〔Example〕

FIG. 1 is a diagram showing the basic configuration of the present invention, in which 1 is a PZ
A piezoelectric bimorph made of T (zirconium titanate) produces bending displacement proportional to the applied voltage. Stoppers (9) are installed on both sides of the piezoelectric plate 10 for positioning the piezoelectric plate 1 and suppressing free vibration of the piezoelectric plate. In a free state where no voltage is applied, the piezoelectric plate l is locked to, for example, a left stopper.

Note that by generating stress corresponding to external vibration between the stopper 9 and the piezoelectric plate 1, an actuator that is resistant to external vibration can be realized. 11 is a fixing base for the piezoelectric plate 1, and the piezoelectric plate is fixed to this by soldering. Electrodes 13A are provided on both sides of the piezoelectric plate 1.
, 13B (only 13A is shown) are formed, and the terminal 15
A predetermined voltage is applied via A and 15B.

In the piezoelectric actuator as described above, according to the present invention, the mass body 21 is fixed to the side surface of the piezoelectric plate 1. The mass body 21 absorbs chattering (vibration) generated when the piezoelectric plate 1 collides with the stopper 9, and its mass and mounting position are determined experimentally depending on the chattering amplitude.

It is most effective to arrange the mass body 21 at the upper end of the piezoelectric plate 1.

FIG. 2 shows an example of specific dimensions of the piezoelectric actuator shown in FIG. 1.

FIG. 3 shows the effects of the stopper 9 and the mass body 21.

From the figure, it can be seen that vibration (chattering) of the piezoelectric plate 1 is suppressed by the combination of the stopper and the mass body, and the position can be changed at high speed.

4A and 4B show the relationship between the mass of the mass body 21 and the chattering decay time. Fig. 4A shows the case where the same mass body 21 is installed on both sides of the upper part of the piezoelectric plate and the mass size is changed, and Fig. 4B shows the case where the same mass body 21 is installed on both sides of the upper part of the piezoelectric plate (30
(2)) is installed, and the mass of the additional mass body (only one side of the piezoelectric plate) 21' provided below is varied.

Chattering is mainly secondary resonance of the piezoelectric plate 1, and this resonance is suppressed by providing a mass body. 4th A,
As can be seen from Figure 4B, the stopper 9 and the mass body 21 can suppress chattering to within 1Qmsec.

The mass body 21 (21') is formed of silicon mass or ceramic mass, for example.

As the piezoelectric plate 1, a ceramic bimorph formed by stacking two piezoelectric plates (ceramic) 31 with a metal slate 33 in between as shown in FIG. 5A can also be used.
As shown in FIG. 5B, it has been confirmed that when LiNbOx with inverted polarization is used, there is no displacement hysteresis and more accurate positioning can be achieved.

In addition, in FIGS. 5A and 5B, arrows indicate polarization directions.

6A to 60 show an embodiment in which the actuator shown in FIG. 2 is applied to an optical switch. In the figure, the first
Parts that are the same as those shown in the figures are designated by the same numbers.

Basically, the piezoelectric plate is the seventh type except that it has two mass bodies.
It is similar to the optical switch shown in the figure, and a movable optical fiber (multimode optical fiber) 43A is fixed to the upper surface of the piezoelectric Fi1 via a fiber guide 41A, while a fixed optical fiber (multimode optical fiber) 43B is fixed to the upper surface of the piezoelectric Fi1 through a fiber guide. It is fixedly supported by the casing 50 via 41B.

Stopper 9 is also fixed to casing 50.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to realize a piezoelectric actuator that can accurately obtain a displacement on the order of several hundred sifrons within 1OIIIsec, and when applied to an optical switch, high-precision high-speed switching is possible and practical. It's very sexual.

[Brief explanation of the drawing]

FIG. 1 is an illustrative diagram showing the basic configuration of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention, FIG. 3 is a diagram showing the chattering prevention effect of the piezoelectric plate, and FIGS. 4A and 4B. is a diagram showing the relationship between chattering decay time and mass; FIGS. 5A and 5B are diagrams showing two configuration examples of piezoelectric plates; FIG. 6A;
6B and 6C are a plan view, a front view, and a side view of an optical switch according to the present invention, and FIG. 7 is a perspective view showing an optical switch using a conventional piezoelectric actuator. 1... Piezoelectric plate, 9... Stopper, 2
1...mass body.

Claims (1)

[Claims] 1. A piezoelectric actuator comprising a piezoelectric plate (1) that bends and displaces in proportion to an applied voltage, and stoppers (9) for regulating the displacement position of the piezoelectric plate on both sides, the piezoelectric actuator comprising: A piezoelectric actuator characterized in that a mass body (21) having a predetermined mass is provided to attenuate the amplitude of chattering generated upon collision with a stopper. 2. The piezoelectric actuator according to claim 1, wherein the piezoelectric plate is formed of LiNbO_3 with inverted polarization. 3. A piezoelectric plate (1) that bends and displaces in proportion to the applied voltage;
stoppers (9) provided on both sides of the piezoelectric plate to regulate the displacement position of the piezoelectric plate; and a mass body (9) of a predetermined mass provided on the piezoelectric plate to attenuate the chattering amplitude that occurs when the piezoelectric plate collides with the stopper. 21), at least one movable optical fiber (43A) displaceably supported at the upper end of the piezoelectric plate, and disposed on one side of the piezoelectric plate opposite to the movable optical fiber, and adapted to the displacement of the piezoelectric plate. a piezoelectric actuator for an optical switch, comprising at least one fixed optical fiber (43B) optically connected to a movable optical fiber.