JPS5932182A - Bimorph piezoelectric element - Google Patents

Abstract

PURPOSE:To obtain high elastic strength and universality in a bimorph piezoelectric element by aligning the polarizing direction of a plurality of piezoelectric plates in the same direction, andbonding thereto a single piezoelectric plate formed by laminating and bonding as one plate. CONSTITUTION:Two piezoelectric plates 1a which have a thickness of t0/2 are aligned as a piezoelectric plate corresponding to a single piezoelectric plate 1 having a thickness of t0 so that the polarizing directions are coincident, laminated and bonded with an adhesive having large elastic deformation state. The single piezoelectric plate 1' which is thus bonded is used and bonded to each of both sides of a metal plate 3, and electrodes 2 are attached to both side surfaces of a piezoelectric element 6'. In this manner, a bimorph piezoelectric element which has high elastic strength and excellent universality can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bimorph piezoelectric element that uses a single layered single electric plate to improve elastic strength and provide versatility.

A bimorph piezoelectric element has, for example, a cross-section or I-) bonded to the phase pressure such that the applied electric ratio stretches one pressure plate and compresses the other pressure plate. There are slight changes (Acchi that allows you to learn standing, : L eta, tri 4
``It is an electromechanical transducer that can learn vibration at a predetermined resonant frequency and is used as a control element, modulator, etc.'' in 41 cities.

A typical bimorph piezoelectric element (114) has two qt -IE plates (1) with polarization directions opposite to each other.
(Fig. 1a), the same Fi41 type with the polarization direction in the same direction (same figure), and the one with one single piezoelectric on one side of the metal plate (3). An illumination model made by pasting plates (1) together (Fig. (Fig. 3), and piezoelectric plates or metal 1iZ are used in the shape of rectangular and 9-disk shapes, depending on the application, for example, in places,
The supporting point C of H is held and used as an actuator, or cantilevered (made with dilute acid is used as an actuator). In Fig. 1, 2 is the attached Il
f, pole.

Here, in the case of the bimorph IF, the relationship between the pressure, the displacement position, and the oscillation frequency in the application of the ``city element'' I is a cantilever I'71j with -all ends fixed. [To explain based on Fig. 2, two single pressure 'tg's are pasted together (1) and the pressure '11' (1) is applied to the element (4), and the support (5) The relationship between the direct LFv and the displacement position (χ) of the pressure-locking element (4) when the voltage IEV is marked/Jll on the electrode attached to the
It is represented by the 戊.

E: Elastic constant L: Yes @Length t: Two piezoelectric plates pasted together PI A: Constant Also, the resonant frequency (Fr) of the piezoelectric element (4) when AC voltage is applied is It is expressed by Equation F (2).

The above pressure: element (4) smell C1 its opening 1t1 (χ
), as is clear from equation (1), it is necessary to increase the effective f4 L or to decrease the bonding thickness t.

However, various types of electronic devices using the piezoelectric element (4) are limited in size, and from the viewpoint of the mechanical strength of the element, the J-method requires a significant change in shape since the structure is made of a single piezoelectric plate. Once the desired displacement number (χ) or resonance frequency (Fr) is determined, the shape of the single piezoelectric plate or metal plate that constitutes the piezoelectric element is specified. .

On the other hand, bimorph pressure sensing elements have a simple structure, are easy to drive, and have low power consumption.
This bimorph piezoelectric element is being used, and there is a strong desire to greatly increase the amplitude when driven at a displacement ridge or a common point when a DC voltage is applied.

However, the bimorph piezoelectric element has a smaller elastic deformation with respect to a constant load than a metal, and is less likely to break due to its small shape and almost no deformation. The methods and shapes specified for the above uses have limitations in their applicability, and there is a problem in that they lack versatility.

This invention? In view of the current situation described above, the present invention aims to propose a bimorph piezoelectric element that has high elastic strength and excellent versatility.

In other words, the present invention is to stack a number of pressure plates with their polarization directions aligned in the same direction using an adhesive with large elastic deformability.
This is a bimorph piezoelectric element in which a single piezoelectric plate, which is connected to each other to form a single piezoelectric plate, is bonded together into a desired shape.

Since the gist of this invention is to use a medium-sized piezoelectric plate having the above-mentioned laminated structure, it can be applied to the various bimorph piezoelectric elements made of 11 elements described above, and can also be applied to various shapes not mentioned above. They can also be bonded together to form a bimorph piezoelectric element.

To be more specific, when applied to various types of timepieces, changes (3γ@ or A plurality of piezoelectric plates with adjusted thickness or length are stacked with their polarization directions aligned so that the resonance frequency is the same. By assembling this into a predetermined bonded shape, a bimorph pressure element is formed.

Therefore, in order to obtain the same performance when assembling a conventional IE electric element using a single piezoelectric plate by using a single-voltage plate consisting of a ms cell structure, the elasticity of the corresponding single piezoelectric plate must be The thickness or dimensions of the multiple piezoelectric plates constituting the laminated layer are selected appropriately so that the physical properties of the piezoelectric plates are the same.
It is not necessary that the base C be the same.

In addition, an epoxy resin adhesive is preferable as the bonding material because it has sufficient flexibility, and furthermore, it can ensure electrical contact by imparting conductivity.

In addition, it is recommended that the polarization Cj provided to the single pressure plate of the laminated structure be confirmed as appropriate depending on the tM configuration of the piezoelectric element, but for example, in the case of the piezoelectric element (4) in FIG. for r
J: Preferably provided on both sides of the element.

Hereinafter, this invention will be explained in detail based on the drawings.

Here, Q will explain the case of a bimorph pressure element having a structure in which a single piezoelectric plate is attached to both sides of one A-side plate. FIG. 8R is a longitudinal cross-sectional view of the above-mentioned (14-component pressure V) element, FIG. 8 is a conventional piezoelectric element, and FIG. 8B is a piezoelectric element according to the present invention.

The conventional piezoelectric element (6) is a single piezoelectric plate (1) with a thickness to
are pasted on both sides of the metal plate (3), and 1 is pasted on the outer surface.
This is a configuration in which an E pole (2) is attached.

On the other hand, the pressure rod (6') according to the present invention is
As a pressure plate corresponding to the piezoelectric plate (1) with a thickness lo, two pressure plate 1E plates (1a) with a thickness /n/2 are aligned so that their polarization directions match, For example, using a piezoelectric plate (1') laminated and bonded with an epoxy resin adhesive,
It is attached to both sides of the metal plate (3), and the electrode (2) is also attached to the metal plate (3).
is attached to both sides of the element (6), where F, the contact layer of 44] t is generally 1 The single piezoelectric plate (l'
) whose elastic constant is the thickness l. Since it is smaller than the conventional single piezoelectric plate (1) consisting of a piezoelectric plate of
It is necessary to make the length of the anti (la) 1 inch thicker than 10/2 or adjust the length.

Next, an example according to the present invention will be shown to clarify its effects. The applied bimorph piezoelectric element is one in which single-ratio IK plates are attached to both sides of the metal plate shown in FIG. 3 described in 1D.

Thickness g, 1'** x Width 5mm x Length 80mm Two sheets of pressure'KL porcelain temporary made of lead zirconate titanate were laminated together using an epoxy resin adhesive. [A single piezoelectric plate was made, and this was attached to both sides of a Rinyo copper plate with a thickness of 0.2 mm x width of 5 mm x length of 30 mm, and a silver electrode of 10 μm thick was placed on the outer surface of the FE electric plate.
The bimorph king of this invention was fired in FJ by 11 digits.
j Two digits.

For comparison, the same composition has a thickness of 0.2 mm x width of 5 mm x length of 30 mm.
Silk single-pressure FL temporary was pasted on both sides of a Rinsaku copper plate of the same size, and one UK pole was similarly installed (=1) to create a conventional bimorph piezoelectric element.

One end of the above two types of piezoelectric elements is placed in a fixture and vibrated at each secondary resonance frequency, and the results of measuring the applied voltage and the amplitude at the free end until the piezoelectric element breaks are shown below. It is shown in Table 1. The reason why the resonance frequency is different between the two is because they are compared as pressure-core elements of the same size.
This is because the thickness or thickness is not adjusted so that the elastic constants of the laminated piezoelectric plate and the conventional single pressure plate are the same.

As is clear from the results, when comparing compression elements of the same size, the amplitude at the free end increases and the elastic strength is significantly improved.

Therefore, when applied to various electronic devices 2g, the piezoelectric buzzer can cope with the required increase in the thigh height 14t of the piezoelectric element in 1 minute, and can also be made to have a long life.

The range of applications has expanded significantly, including speakers, actuators for printers, piezoelectric switches, etc.9.

Gel 1 table

[Brief explanation of the drawing]

Is Figure 1 bimorph pressure? [Longitudinal explanatory diagram showing the typical (16 structure) of the element, Figure 2] (Imo/L,) An explanatory diagram showing the operation of the piezoelectric element, Figure 3 is a longitudinal explanatory diagram of the Imorph piezoelectric element Fig. a shows the conventional example, and Fig. b shows the case of the piezoelectric element f according to the present invention. , 2...+if, pole, 8... metal plate, 4.6.
6'...Roll element, 5...Support. Applicant: Sumitomo Tokushusha Co., Ltd.

Claims (1)

[Claims] l A single piezoelectric plate is bonded together by laminating and bonding a plurality of piezoelectric plates with their polarization directions aligned in the same direction using a contact material with large elastic deformability to form a single piezoelectric plate. Bimorph 1 ball electric element.