CN214043705U

CN214043705U - Piezoelectric actuator

Info

Publication number: CN214043705U
Application number: CN202023165657.3U
Authority: CN
Inventors: 朱兆焱; 秦小勇; 石璐绿; 张喆斯; 田佳琦; 石鹏
Original assignee: Audiowell Electronics Guangdong Co ltd
Current assignee: Audiowell Electronics Guangdong Co ltd
Priority date: 2020-12-24
Filing date: 2020-12-24
Publication date: 2021-08-24
Anticipated expiration: 2030-12-24

Abstract

The utility model provides a piezoelectric actuator, include: the metal substrate is provided with a ceramic wafer, and the ceramic wafer is provided with a first copper electrode; the ceramic plate is connected with the metal substrate through a matching layer, a second copper electrode is arranged between the ceramic plate and the matching layer, and the second copper electrode is communicated with the metal substrate; the first copper electrode is arranged on the upper surface of the ceramic chip, the area of the first copper electrode is smaller than that of the ceramic chip, and a remaining edge part is arranged. The utility model discloses piezoelectric actuator adopts the copper electrode, drives under the powerful condition of high temperature high pressure, can not take place the migration of ion yet, can not influence the performance of product to improve the reliability of product and guarantee the life-span of product.

Description

Piezoelectric actuator

Technical Field

The utility model belongs to the technical field of piezoelectric actuator technique and specifically relates to indicate a can realize the piezoelectric actuator of tactile feedback under high-power high voltage drive.

Background

The traditional piezoelectric actuator is low in driving voltage (100-500 v/mm), a unidirectional pressurizing mode is usually adopted for driving, and a silver or silver palladium electrode is adopted according to a conventional mode to meet the use and reliability requirements of products.

However, with the development of miniaturization of the piezoelectric actuator, the driving field strength of the piezoelectric actuator needs to be increased to 1000-3000 v/mm, in this case, a phenomenon that silver or silver palladium electrodes are transferred from the mechanism exists (as shown in fig. 1). To further enhance the use of the device, the piezoelectric device is often driven in a biased manner (e.g., 300v forward and 100v reverse), and this use can increase the mobility of ions. After the piezoelectric actuator works for a period of time under high voltage, the distance between the positive electrode and the negative electrode is reduced due to ion migration, the voltage resistance of a product is reduced, the product is ignited or short-circuited, and the service life and the reliability of the product cannot be effectively guaranteed.

For solving the reliability of the piezoelectric actuator, the common methods in the market include: the density of the ceramic is improved, the sealing performance of the piezoelectric device is improved, and the distance between the anode and the cathode of the piezoelectric device is increased, so that the migration speed can be only delayed, and the problems of the service life and the reliability of the device cannot be fundamentally solved.

The strain of the piezoelectric actuator and the driving voltage show a linear relationship in principle, that is, the strain of the piezoelectric actuator increases with the increase of the driving voltage. However, in an actual scene, when the driving voltage of the piezoelectric actuator using the silver or silver-palladium electrode is increased to a higher level (e.g., >500v/mm), the strain increase of the piezoelectric actuator is obviously delayed from the increase of the driving voltage, the heat generation of the device is also obviously increased, and the product is easily broken down.

SUMMERY OF THE UTILITY MODEL

The utility model provides a can realize the piezoelectric actuator of sense of touch feedback under high-power high voltage drive.

The utility model adopts the technical proposal that: a piezoelectric actuator comprising: the metal substrate is provided with a ceramic wafer, and the ceramic wafer is provided with a first copper electrode; the ceramic plate is connected with the metal substrate through a matching layer, a second copper electrode is arranged between the ceramic plate and the matching layer, and the second copper electrode is communicated with the metal substrate; the first copper electrode is arranged on the upper surface of the ceramic chip, the area of the first copper electrode is smaller than that of the ceramic chip, and a remaining edge part is arranged.

Preferably, the first copper electrode and the second copper electrode are attached to the ceramic sheet by means of firing.

Preferably, the first copper electrode and the second copper electrode are of thick film structures, and the thickness of the copper electrodes is 7-13 microns.

Preferably, the first copper electrode and the second copper electrode are formed by copper paste, and the copper paste is composed of copper powder with the particle size of 0.1-5.0 um and trace oxides or glass.

Preferably, the surface area of the first copper electrode accounts for 75-86% of the surface area of the ceramic wafer.

Preferably, the matching layer is glue, and glue overflow is generated when the ceramic plate is adhered to the metal substrate.

Preferably, the glue overflow forms a rubber ring between the edge of the ceramic plate and the metal substrate.

Preferably, the surface between the first copper electrode and the metal substrate is coated with a layer of solder resist insulation protective paint, and the first copper electrode is spaced from the metal substrate.

Preferably, the thickness of the solder resist insulation protective paint is 5-15 microns.

Preferably, the solder resist insulating protective paint covers the outer edge of the first copper electrode, the edge part, the rubber ring and part of the surface of the metal substrate.

Compared with the prior art, the utility model discloses piezoelectric actuator adopts the copper electrode, drives under the powerful condition of high temperature high pressure, can not take place the migration of ion yet, can not influence the performance of product to improve the reliability of product and guarantee the life-span of product.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings, there is shown in the drawings,

FIG. 1: the phenomenon that silver or silver palladium electrodes of the existing piezoelectric actuator are transferred from the mechanism exists in the diagram;

FIG. 2: the utility model discloses one of the structural schematic diagrams of piezoelectric actuator;

FIG. 3: is a cross-sectional view a-a of fig. 2;

FIG. 4: is an enlarged view of B of fig. 3;

FIG. 5: the second structural schematic diagram of the piezoelectric actuator of the present invention;

FIG. 6: the third structural schematic diagram of the piezoelectric actuator of the present invention;

FIG. 7: the utility model discloses a phenomenon picture that ion migration can not take place between the first copper electrode and the second copper electrode of the piezoelectric actuator;

FIG. 8: the utility model discloses one of them application schematic diagram of piezoelectric actuator;

FIG. 9: the utility model discloses a driving voltage schematic diagram of a piezoelectric actuator in the asymmetric voltage working process;

FIG. 10: a schematic diagram of the driving voltage-piezoelectric characteristics of the piezoelectric actuator using the copper electrode and the silver electrode.

Names and designations of parts

Positive electrode 100

Ceramic wafer 200

Migration channel 300

Negative electrode 400

Metal substrate 1

Ceramic plate 2

First copper electrode 3

Second copper electrode 4

Matching layer 5

Edge retaining part 6

Solder resist insulating protective paint 7

Rubber ring 8

Detailed Description

The following detailed description of the embodiments of the present invention will be made with reference to the accompanying drawings. It is to be understood that the description of the embodiments herein is for purposes of illustration and explanation only and is not intended to limit the invention.

As shown in fig. 2 to 5, the piezoelectric actuator of the present invention includes: the device comprises a metal substrate 1, wherein a ceramic plate 2 is arranged on the metal substrate 1, and a first copper electrode 3 is arranged on the ceramic plate 2. The ceramic plate 2 is connected with the metal substrate 1 through a matching layer 5, a second copper electrode 4 is arranged between the ceramic plate 2 and the matching layer 5, and the second copper electrode 4 is communicated with the metal substrate 1. The copper electrode is arranged on the upper surface of the ceramic plate 2, the area of the copper electrode is smaller than that of the ceramic plate 2, a remaining edge part 6 is arranged, electric arcs can be formed between the two electrodes under high voltage, the remaining edge part 6 is arranged to enable a certain safety distance to exist between positive voltage and negative voltage, and the risk of breakdown is reduced.

As shown in fig. 3 and 4, the first copper electrode 3 and the second copper electrode 4 are attached to the ceramic sheet 2 by sintering. The first copper electrode 3 and the second copper electrode 4 are of thick film structures, the thickness of the copper electrodes is 7-13 microns, and the performance of the thickness is good. The first copper electrode 3 and the second copper electrode 4 are formed by copper slurry, and the copper slurry is sintered and infiltrated on the upper surface and the lower surface of the ceramic plate 2 to form the copper electrodes. The copper paste is composed of copper powder with the particle size of 0.1-5.0 um and trace oxide or glass, and a copper electrode formed by the copper paste is good in performance, simple in process and good in reliability. Under the conditions of high power and strong voltage, the copper electrode formed by the copper paste has stable performance and stable amplitude, the ceramic wafer 2 is not easy to break down, and a migration channel cannot be generated, as shown in fig. 7. The copper electrode formed by the copper slurry has the withstand voltage of more than 1500V per millimeter, and the driving amplitude is increased. When the silver paste is used as an electrode, under the conditions of high power and strong voltage, the amplitude is unstable and can be reduced, and the ceramic sheet 2 can generate a migration channel and even be broken down, as shown in fig. 1, so that the product loses the performance.

As shown in fig. 5, the surface area of the first copper electrode 3 accounts for 75-86% of the surface area of the ceramic sheet 2. In this embodiment, the ceramic sheet 2 is a circular sheet, the first copper electrode 3 is also a circular, and the edge-remaining portion 6 is a circular ring outside the first copper electrode 3.

As shown in fig. 4 and 5, the matching layer 5 is glue, and the glue generates glue overflow when the ceramic sheet 2 is adhered to the metal substrate 1. The glue overflow forms a rubber ring 8 between the edge of the ceramic plate 2 and the metal substrate 1.

As shown in fig. 4 and 5, the surface between the first copper electrode 3 and the metal substrate 1 is coated with a solder resist insulating protective paint 7 to space the first copper electrode 3 from the metal substrate 1. The thickness of the solder resist insulating protective paint 7 is 5-15 micrometers, so that the risk of electric arcs formed on the surfaces of the anode and the cathode under high voltage is greatly reduced. The solder resist insulating protective paint 7 covers the outer edge of the first copper electrode 3, the edge retaining part 6, the rubber ring 8 and part of the surface of the metal substrate 1, so that an anode and a cathode which are not interfered with each other are effectively formed.

As shown in fig. 7, under the premise of high power and high voltage, no ion migration occurs between the first copper electrode 3 and the second copper electrode 4, and the product is not broken down. The piezoelectric actuator formed by the copper electrodes is used as a brake component to realize the on-line touch feedback device of the touch sense, and has the advantages of high response speed, wide driving frequency band, high vibration intensity, fine and real vibration experience feeling, low acoustic noise and low power consumption. When a steady-state excitation signal is applied to the piezoelectric actuator, the piezoelectric actuator can be excited to vibrate, and different tactile feedbacks can be obtained by adjusting different vibration frequencies of the piezoelectric actuator.

Fig. 8 is a schematic diagram of an application of the piezoelectric actuator. And the piezoelectric actuator is externally provided with a tactile pressing force, the piezoelectric actuator is conducted, an excitation steady-state signal is fed back to the MCU processor for signal processing, a function corresponding to the tactile pressing can be realized after the signal processing, and meanwhile, the MCU processor provides high-voltage driving tactile feedback to the piezoelectric actuator.

As shown in fig. 9, the piezoelectric actuator can work under the condition that the positive voltage and the negative voltage are asymmetric, and meanwhile, the performance is stable and reliable, and the service life is not affected.

As shown in fig. 10, the upper curve 1 shows the piezoelectric characteristics of the copper electrode at different driving voltages, and the lower curve 2 shows the piezoelectric characteristics of the silver electrode at different driving voltages. The curve 1 has higher piezoelectric characteristics than the curve 2 under the same driving voltage, and the inflection point driving voltage of the curve 1 is higher than the inflection point driving voltage of the curve 2. That is, the curve 1 shows a higher piezoelectric characteristic even when the driving voltage is increased, but the inflection point of the curve 1 appears later than the inflection point of the curve 2, that is, the inflection point of the piezoelectric characteristic of the curve 2 appears when the piezoelectric characteristic of the curve 1 is increased.

As long as the idea created by the present invention is not violated, various different embodiments of the present invention can be arbitrarily combined, and all the embodiments should be regarded as the content disclosed by the present invention; the utility model discloses an in the technical conception scope, carry out multiple simple variant and different embodiments to technical scheme and go on not violating the utility model discloses the arbitrary combination of the thought of creation all should be within the protection scope.

Claims

1. A piezoelectric actuator, comprising:

the metal substrate is provided with a ceramic wafer, and the ceramic wafer is provided with a first copper electrode;

the ceramic plate is connected with the metal substrate through a matching layer, a second copper electrode is arranged between the ceramic plate and the matching layer, and the second copper electrode is communicated with the metal substrate;

the first copper electrode is arranged on the upper surface of the ceramic chip, the area of the first copper electrode is smaller than that of the ceramic chip, and a remaining edge part is arranged.

2. The piezoelectric actuator of claim 1, wherein: the first copper electrode and the second copper electrode are attached to the ceramic sheet by means of sintering.

3. The piezoelectric actuator of claim 1, wherein: the first copper electrode and the second copper electrode are of thick film structures, and the thickness of the copper electrodes is 7-13 microns.

4. The piezoelectric actuator of claim 1, wherein: the first copper electrode and the second copper electrode are formed by copper slurry, and the copper slurry is composed of copper powder with the particle size of 0.1-5.0 um and trace oxide or glass.

5. The piezoelectric actuator of claim 1, wherein: the surface area of the first copper electrode accounts for 75-86% of the surface area of the ceramic plate.

6. The piezoelectric actuator of claim 1, wherein: the matching layer is glue, and the glue overflows when the ceramic chip is stuck with the metal substrate.

7. The piezoelectric actuator of claim 6, wherein: and the overflowing glue forms a rubber ring between the edge of the ceramic plate and the metal substrate.

8. The piezoelectric actuator of claim 7, wherein: and a layer of solder resist insulation protective paint is coated on the surface between the first copper electrode and the metal substrate to separate the first copper electrode and the metal substrate.

9. The piezoelectric actuator of claim 8, wherein: the thickness of the solder resist insulating protective paint is 5-15 microns.

10. The piezoelectric actuator of claim 8, wherein: the solder resist insulating protective paint covers the outer edge of the first copper electrode, the edge retaining part, the rubber ring and part of the surface of the metal substrate.