CN115454249A - Piezoelectric element, piezoelectric vibrator, and electronic device - Google Patents

Abstract

The embodiment of the invention provides a piezoelectric element, a piezoelectric vibrator and electronic equipment, wherein a defect repairing layer with the dielectric constant larger than that of a piezoelectric material layer is arranged between the piezoelectric material layer and a second electrode, so that when the piezoelectric material layer has defect sites generated due to manufacturing processes and the like, the defect repairing layer can fill the defect sites, namely the defect repairing layer can repair the surface of the piezoelectric material layer, the phenomenon of breakdown caused by the arc effect of point discharge due to the existence of the defect sites is avoided, and the problem of failure of the piezoelectric element can be avoided.

Description

Piezoelectric elements, piezoelectric vibrators, and electronic devices

technical field

The invention relates to the field of piezoelectric technology, in particular to a piezoelectric element, a piezoelectric vibrator and electronic equipment.

Background technique

With the rapid advancement of electronic technology, people have higher and higher requirements for the experience of using electronic devices. Most of the current electronic devices can only provide visual and auditory experience, but cannot bring users a tactile experience. Therefore, tactile reproduction Technology came into being.

In the existing tactile reproduction technology, a piezoelectric element is provided in an electronic device to provide tactile feedback through vibration of the piezoelectric element. However, in the existing piezoelectric element, when the surface charge is unevenly distributed and accumulated or the voltage is too high, breakdown will occur, and the breakdown of the piezoelectric element will cause the piezoelectric element or even the entire vibration device to fail .

Contents of the invention

Embodiments of the present invention provide a piezoelectric element, a piezoelectric vibrator and electronic equipment, which are used to solve the problem that the piezoelectric element or even the entire vibrating device fails due to breakdown.

An embodiment of the present invention provides a piezoelectric element, including: a first electrode, a piezoelectric material layer disposed on one side of the first electrode, and a piezoelectric material layer disposed on a side of the piezoelectric material layer away from the first electrode. A defect repairing layer, and a second electrode disposed on a side of the defect repairing layer away from the first electrode; wherein, the dielectric constant of the defect repairing layer is greater than that of the piezoelectric material layer.

In a possible implementation manner, in the piezoelectric element provided in the embodiment of the present invention, the material of the defect repairing layer includes at least one of PbZrO ₃ , BaTiO ₃ , and ZrTiO ₃ .

In a possible implementation manner, in the piezoelectric element provided in the embodiment of the present invention, the thickness of the defect repairing layer is greater than 0.1 times the thickness of the piezoelectric material layer.

In a possible implementation manner, in the piezoelectric element provided in the embodiment of the present invention, the second electrode includes a plurality of second sub-electrodes distributed in an array, and every two adjacent second sub-electrodes Electrically connected through an independent connection structure, and the connection structure is located on the side of the second electrode away from the first electrode; wherein,

The material of the first electrode and the material of the second electrode are both transparent conductive materials, and the material of the connection structure is metal.

In a possible implementation manner, in the piezoelectric element provided in the embodiment of the present invention, the connection structure includes a first connection portion and a second connection portion that are stacked and electrically connected, and the first connection portion and the second connection portion are electrically connected. The second sub-electrode contacts are electrically connected; wherein, the material of the first connection part includes Ti or Cr, and the material of the second connection part includes Al or Au.

In a possible implementation manner, in the piezoelectric element provided in the embodiment of the present invention, the first connection part includes a first sub-connection part and a second sub-connection part that are independently provided, and the first sub-connection part The second sub-electrode is in contact with one of the two adjacent second sub-electrodes, and the second sub-connecting part is in contact with the second sub-electrode of the other two adjacent second sub-electrodes. The two sub-electrodes are in contact with each other for electrical connection.

In a possible implementation manner, in the piezoelectric element provided in the embodiment of the present invention, the thickness of the first connection part is less than 10 nm, and the thickness of the second connection part is less than 500 nm.

In a possible implementation manner, the piezoelectric element provided in the embodiment of the present invention further includes an insulating layer located between the second electrode and the connecting structure, and the connecting structure passes through the insulating layer The via hole is electrically connected to the second sub-electrode.

In a possible implementation manner, in the piezoelectric element provided in the embodiment of the present invention, the thickness of the insulating layer is greater than twice the thickness of the second sub-electrode.

In a possible implementation manner, in the piezoelectric element provided in the embodiment of the present invention, the material of the insulating layer is photoresist or SiO ₂ .

In a possible implementation manner, in the piezoelectric element provided in the embodiment of the present invention, the thickness of the piezoelectric material layer is 500 nm˜2000 nm.

In a possible implementation, in the piezoelectric element provided in the embodiment of the present invention, the piezoelectric material layer includes lead zirconate titanate, aluminum nitride, zinc oxide, barium titanate, lead titanate, niobate At least one of potassium, lithium niobate, lithium tantalate, and gallium lanthanum silicate.

Correspondingly, an embodiment of the present invention also provides a piezoelectric vibrator, including a base substrate and a plurality of piezoelectric elements as described in any one of the above provided by the embodiments of the present invention provided on the base substrate .

Correspondingly, an embodiment of the present invention further provides an electronic device, including the above-mentioned piezoelectric vibrator provided by the embodiment of the present invention.

The beneficial effects of the embodiments of the present invention are as follows:

A piezoelectric element, a piezoelectric vibrator, and an electronic device provided by an embodiment of the present invention, a defect repairing layer having a dielectric constant greater than the dielectric constant of the piezoelectric material layer is provided between the piezoelectric material layer and the second electrode, so that When the piezoelectric material layer has defect sites due to manufacturing process and other reasons, the defect repair layer can fill the defect sites, that is, the defect repair layer can repair the surface of the piezoelectric material layer to avoid the formation of sharp points due to the existence of defect sites. The phenomenon of breakdown occurs due to the arc effect of the discharge, so that the failure of the piezoelectric element can be avoided.

Description of drawings

FIG. 1 is a schematic structural diagram of a piezoelectric element provided in the related art;

FIG. 2 is a schematic structural diagram of a piezoelectric element provided by an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of another piezoelectric element provided by an embodiment of the present invention;

Fig. 4 is a schematic plan view of part of the film layer in Fig. 3;

Fig. 5 is a schematic diagram of the repair when the piezoelectric element breaks down;

FIG. 6 is a schematic structural diagram of another piezoelectric element provided by an embodiment of the present invention;

Fig. 7 is a schematic structural diagram of a piezoelectric vibrator provided by an embodiment of the present invention.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the following will clearly and completely describe the technical solutions of the embodiments of the present invention in conjunction with the drawings of the embodiments of the present invention. Apparently, the described embodiments are some, not all, embodiments of the present invention. And in the case of no conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. Based on the described embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the usual meanings understood by those skilled in the art to which the present invention belongs. The words "comprising" or "comprising" and similar words used in the present invention mean that the elements or objects appearing before the words include the elements or objects listed after the words and their equivalents, without excluding other elements or objects. Words such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Inner", "outer", "upper", "lower" and so on are only used to indicate relative positional relationship. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

It should be noted that the size and shape of each figure in the drawings do not reflect the actual scale, but are only intended to schematically illustrate the content of the present invention. And the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout.

In the related art, as shown in FIG. 1, the piezoelectric element includes: a first electrode 1, a piezoelectric material layer 2 (such as PZT) disposed on the first electrode 1, and a second piezoelectric material layer disposed on the piezoelectric material layer 2. Two electrodes 3. During the working process of the piezoelectric element, the first electrode 1 is grounded by using the inverse piezoelectric effect, and a high-frequency AC voltage is applied to the piezoelectric material layer 2 by applying a high-frequency AC voltage signal (V _AC ) to the second electrode 3 The application of the signal, resulting in high-frequency vibration. However, breakdown occurs when the charge on the surface of the piezoelectric element is unevenly distributed and accumulates or the voltage is too high. The breakdown of the piezoelectric element may lead to two results, one is that the first electrode 1 and the second electrode 3 remain open, but the PZT layer structure is damaged; the other is that the first electrode 1 and the second electrode 3 are caused by breakdown A short circuit will cause the piezoelectric element or even the entire vibration device to fail. However, the reasons for the breakdown of the piezoelectric element can be divided into two categories. One is the heating effect of the wiring, that is, when the heat generated by the piezoelectric element during operation is much greater than the heat dissipated, the piezoelectric element is prone to breakdown at this time. The problem of breakdown and trace burning; the other is that when the instantaneous temperature of the piezoelectric element reaches the PZT phase separation temperature, PZT volume change and arc effect (Arc) will occur at the same time. Arc is when the first electrode 1 and the second When the electrode 3 has a voltage difference, it has a potential to generate Arc. This potential is related to the distance between the first electrode 1 and the second electrode 3 and the electrothermal density. When there are defect sites 4 in the PZT film layer, the distance is shortened , and if the defect site 4 has a pointed shape, an arc effect of a pointed discharge will be formed at this time, and a breakdown will occur.

In view of this, in order to avoid the failure of the piezoelectric element caused by the breakdown of the piezoelectric element, an embodiment of the present invention provides a piezoelectric element, as shown in FIG. 2 , including: a first electrode 1 arranged on the first electrode The piezoelectric material layer 2 on one side of the piezoelectric material layer 2, the defect repairing layer 5 disposed on the side of the piezoelectric material layer 2 facing away from the first electrode 1, and the second electrode 3 disposed on the side of the defect repairing layer 5 facing away from the first electrode 1; Wherein, the dielectric constant of the defect repairing layer 5 is greater than that of the piezoelectric material layer 2 .

In the above-mentioned piezoelectric element provided by the embodiment of the present invention, a defect repairing layer 5 having a dielectric constant greater than that of the piezoelectric material layer 2 is provided between the piezoelectric material layer 2 and the second electrode 3, so that when the piezoelectric material layer 2 When defect sites 4 are generated due to manufacturing process and other reasons, the defect repair layer 5 can fill the defect sites 4, that is, the defect repair layer 5 can repair the surface of the piezoelectric material layer 2, avoiding the occurrence of defects due to the existence of defect sites 4. The phenomenon of breakdown occurs due to the arc effect of the formation of the tip discharge, so that the failure of the piezoelectric element can be avoided.

In specific implementation, in the above piezoelectric element provided by the embodiment of the present invention, as shown in FIG. 2 , the material of the defect repairing layer 5 may include but not limited to at least one of PbZrO ₃ , BaTiO ₃ , and ZrTiO ₃ .

It should be noted that the materials of the defect repairing layer 5 listed above are all inorganic materials, of course, they can also be organic materials, as long as their dielectric constant is greater than that of the piezoelectric material layer 2 .

In actual implementation, since the piezoelectric element itself is also a capacitive structure, in order to ensure the ability of the capacitor itself to store charges, the thickness of the defect repair layer should be as small as possible to ensure that the setting of the defect repair layer does not affect the original capacitance of the piezoelectric element. Storage capacity, but considering the repairing ability of the defect repairing layer to the defect sites in the piezoelectric material layer, the defect repairing layer needs to have a certain thickness, so considering the storage capacity of the capacitor and the repairing ability of the defect repairing layer, in the present invention In the above piezoelectric element provided in the embodiment, as shown in FIG. 2, the thickness of the defect repairing layer 5 is greater than 0.1 times the thickness of the piezoelectric material layer 2, so that the setting of the defect repairing layer 5 can not only ensure the storage capacity of charges, but also The piezoelectric material layer 2 is well filled and repaired.

In a specific implementation, the thickness of the piezoelectric material layer may be 500nm-2000nm. For example, when the thickness of the piezoelectric material layer can be 500nm, the thickness of the defect repairing layer 5 should be greater than 50nm; when the thickness of the piezoelectric material layer can be 600nm, the thickness of the defect repairing layer 5 should be greater than 60nm; The thickness of the piezoelectric material layer may be 1000 nm, and at this time the thickness of the defect repairing layer 5 should be greater than 100 nm; and so on.

In specific implementation, in the above-mentioned piezoelectric element provided by the embodiment of the present invention, as shown in Figure 3 and Figure 4, Figure 4 is a schematic plan view of the second electrode 3 in Figure 3, of course, Figure 3 only shows the piezoelectric element Partial structure of the element, the second electrode 3 includes a plurality of second sub-electrodes 31 distributed in an array, each adjacent two second sub-electrodes 31 are electrically connected through an independent connection structure 6, and the connection structure 6 is located on the second electrode 3 is away from the side of the first electrode 1; wherein,

The material of the first electrode 1 and the material of the second electrode 3 can be both transparent conductive materials, for example can be indium tin oxide (ITO), can also be indium zinc oxide (IZO) etc.; The material of connecting structure 6 can be metal, For example Ti/Al etc. In this way, when a breakdown occurs at a certain position on the surface of the piezoelectric element, as shown in Figure 5, for example, a short-circuit breakdown occurs in the second sub-electrode 31 at the position of the second column and the third row, and local heating occurs at this position. , because the volume energy density of metal is much smaller than that of transparent conductive materials such as ITO, the heat production of the connection structure 6 will be much higher than the heat production of the first electrode/piezoelectric material layer/second electrode, and the breakdown will occur The connection structure 6 around the second sub-electrode 31 is preferentially fused, so that the second sub-electrode 31 at the location where the breakdown occurs is isolated from the rest of the second sub-electrodes 31 by an open circuit, so that the rest of the second sub-electrodes 31 will not be broken down and burned , so that the failure of the entire piezoelectric element can be avoided.

In specific implementation, in the above piezoelectric element provided by the embodiment of the present invention, the thickness of the first electrode may be 250 nm to 500 nm, and the thickness of the second electrode may be 250 nm to 500 nm.

In specific implementation, in the above-mentioned piezoelectric element provided by the embodiment of the present invention, as shown in FIG. The portion 61 is electrically connected to the second sub-electrode 31 ; wherein, the material of the first connecting portion 61 may include Ti or Cr, and the material of the second connecting portion 62 may include Al or Au. In this way, the first connection part 61 acts as an adhesive layer to enhance the adhesion between the second connection part 62 and the second sub-electrode 31; The two electrodes are loaded with a high-frequency AC voltage signal, and the first electrode 1 is grounded.

In specific implementation, in the above-mentioned piezoelectric element provided by the embodiment of the present invention, as shown in FIG. The connection part 611 is electrically connected to one of the second sub-electrodes 31 of the two adjacent second sub-electrodes 31 , and the second sub-connection part 612 is connected to the other second sub-electrode of the two adjacent second sub-electrodes 31 . 31 contact electrical connections. In this way, the first sub-connection part 611 and the second sub-connection part 612 are only provided at the place in contact with the second sub-electrode 31, that is, there is Ti or Cr only at the place in contact with the second sub-electrode 31, and all other positions are conductive. The functioning second connection portion 62 (Al or Au) can improve the electrical conductivity of the connection structure 6 .

In specific implementation, in the above-mentioned piezoelectric element provided by the embodiment of the present invention, as shown in FIG. 6 , the thickness of the first connecting portion 61 may be less than 10 nm, such as 5 nm; the thickness of the second connecting portion 62 may be less than 500 nm, such as 100nm.

In specific implementation, in the above-mentioned piezoelectric element provided by the embodiment of the present invention, as shown in FIG. 3 and FIG. The via hole in the insulating layer 7 is electrically connected to the second sub-electrode 31 . Specifically, the insulating layer 7 has a protective effect and can prevent the connection structure 6 from being damaged or oxidized.

In specific implementation, in the above-mentioned piezoelectric element provided by the embodiment of the present invention, as shown in Figure 3 and Figure 6, the thickness of the insulating layer 7 can be greater than twice the thickness of the second sub-electrode 31; the material of the insulating layer 7 can be It is photoresist, SiO ₂ or silicon nitride (Si ₃ N ₄ ), etc., which is not limited here.

In specific implementation, the piezoelectric element provided in the embodiment of the present invention may be provided with other film layers in addition to the above-mentioned film layers according to practical applications.

In specific implementation, the piezoelectric material layer is not limited to lead zirconate titanate (Pb(Zr,Ti)O ₃ , PZT), but can also be aluminum nitride (AlN), ZnO (zinc oxide), barium titanate (BaTiO ₃ ), lead titanate (PbTiO ₃ ), potassium niobate (KNbO ₃ ), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), lanthanum gallium silicate (La ₃ Ga ₅ SiO ₁₄ ) In this way, while taking into account the transparency of the piezoelectric element, the vibration characteristics of the piezoelectric element are guaranteed. Specifically, the material for making the piezoelectric material layer can be selected according to the actual needs of those skilled in the art, and is not limited here. . When PZT is used to make the piezoelectric material layer, because PZT has a high piezoelectric coefficient, the piezoelectric characteristics of the corresponding piezoelectric element are guaranteed, and the corresponding piezoelectric element can be applied to the tactile feedback device, and PZT has a high When it is integrated into a display device, it does not affect the display quality of the display device.

To sum up, the piezoelectric element provided by the embodiment of the present invention, on the one hand, can avoid breakdown caused by defect sites in the piezoelectric material layer by setting the defect repair layer; on the other hand, by setting the second electrode into a plurality of independently arranged second sub-electrodes, and each second sub-electrode is electrically connected through a connection structure, so that when a breakdown occurs at a local location, the second sub-electrode at the breakdown location can be isolated from the rest of the second sub-electrodes , to ensure that the remaining second sub-electrodes do not break down and be burned, thereby avoiding the failure of the entire piezoelectric element.

The piezoelectric element provided by the embodiment of the present invention can be applied to fields such as medical treatment, automotive electronics, and motion tracking systems. It is especially suitable for the field of wearable devices, monitoring and treatment outside the body or implanted in the human body, or electronic skin applied to artificial intelligence and other fields. Specifically, the piezoelectric element can be applied to brake pads, keyboards, mobile terminals, game handles, vehicles, and other devices that can generate vibration and mechanical characteristics.

Based on the same inventive concept, an embodiment of the present invention also provides a piezoelectric vibrator, as shown in FIG. Element 20.

In the specific implementation process, the substrate can be a flexible substrate or a rigid substrate. For example, the material of the flexible substrate can be PI (Polyimide, polyimide), PET (PolyethyleneTerephthalate, poly pair Ethylene phthalate) or PDMS (Polydimethylsiloxane, polydimethylsiloxane), etc., the rigid substrate substrate can actually be a glass substrate, a sapphire substrate, etc.

During specific implementation, the piezoelectric vibrator provided by the embodiment of the present invention may also be provided with other structures according to practical applications.

Based on the same inventive concept, an embodiment of the present invention further provides an electronic device, including the above-mentioned piezoelectric vibrator provided by the embodiment of the present invention. Since the problem-solving principle of the electronic device is similar to that of the aforementioned piezoelectric element, the implementation of the electronic device can refer to the implementation of the aforementioned piezoelectric element, and repeated descriptions will not be repeated.

In actual products, the electronic equipment can be a display device, which includes a display panel and the above-mentioned piezoelectric vibrator, and the piezoelectric vibrator can be arranged on the light-emitting side of the display panel, so that the display device can simultaneously realize display function and tactile reproduction Function.

Of course, the electronic device in the embodiment of the present invention is not limited to the display device, and it can also be any product or component with a tactile reproduction function.

A piezoelectric element, a piezoelectric vibrator, and an electronic device provided by an embodiment of the present invention, a defect repairing layer having a dielectric constant greater than the dielectric constant of the piezoelectric material layer is provided between the piezoelectric material layer and the second electrode, so that When the piezoelectric material layer has defect sites due to manufacturing process and other reasons, the defect repair layer can fill the defect sites, that is, the defect repair layer can repair the surface of the piezoelectric material layer to avoid the formation of sharp points due to the existence of defect sites. The phenomenon of breakdown occurs due to the arc effect of the discharge, so that the failure of the piezoelectric element can be avoided.

While preferred embodiments of the invention have been described, additional changes and modifications to these embodiments can be made by those skilled in the art once the basic inventive concept is appreciated. Therefore, it is intended that the appended claims be construed to cover the preferred embodiment as well as all changes and modifications which fall within the scope of the invention.

Apparently, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. In this way, if the modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present invention and equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (14)

1. A piezoelectric element, comprising: the piezoelectric element comprises a first electrode, a piezoelectric material layer arranged on one side of the first electrode, a defect repairing layer arranged on one side, away from the first electrode, of the piezoelectric material layer, and a second electrode arranged on one side, away from the first electrode, of the defect repairing layer; wherein the dielectric constant of the defect repair layer is greater than the dielectric constant of the piezoelectric material layer.

2. The piezoelectric element according to claim 1, wherein a material of the defect repair layer includes PbZrO ₃ 、BaTiO ₃ 、ZrTiO ₃ At least one of them.

3. The piezoelectric element according to claim 1, wherein a thickness of the defect repair layer is greater than 0.1 times a thickness of the piezoelectric material layer.

4. The piezoelectric element according to any one of claims 1 to 3, wherein the second electrode comprises a plurality of second sub-electrodes distributed in an array, every two adjacent second sub-electrodes are electrically connected through a separate connecting structure, and the connecting structure is located on a side of the second electrode facing away from the first electrode; wherein,

the first electrode and the second electrode are made of transparent conductive materials, and the connecting structure is made of metal.

5. The piezoelectric element according to claim 4, wherein the connection structure includes a first connection portion and a second connection portion which are arranged in a stack and electrically connected, the first connection portion being electrically connected in contact with the second sub-electrode; wherein the material of the first connecting part comprises Ti or Cr, and the material of the second connecting part comprises Al or Au.

6. The piezoelectric element according to claim 5, wherein the first connecting portion includes a first sub-connecting portion and a second sub-connecting portion which are separately provided, the first sub-connecting portion being electrically connected to one of the second sub-electrode contacts of two adjacent second sub-electrodes, and the second sub-connecting portion being electrically connected to the other of the second sub-electrode contacts of two adjacent second sub-electrodes.

7. The piezoelectric element according to claim 5, wherein the thickness of the first connection portion is less than 10nm, and the thickness of the second connection portion is less than 500nm.

8. The piezoelectric element according to any one of claims 5 to 7, further comprising an insulating layer between the second electrode and the connection structure, the connection structure being electrically connected to the second sub-electrode through a via hole penetrating the insulating layer.

9. The piezoelectric element according to claim 8, wherein a thickness of the insulating layer is more than 2 times a thickness of the second sub-electrode.

10. The piezoelectric element according to claim 8, wherein a material of the insulating layer is a photoresist or SiO ₂ 。

11. The piezoelectric element according to any one of claims 1 to 3, 5 to 7, 9 and 10, wherein the thickness of the piezoelectric material layer is 500nm to 2000nm.

12. The piezoelectric element according to any one of claims 1 to 3, 5 to 7, 9 and 10, wherein the piezoelectric material layer includes at least one of lead zirconate titanate, aluminum nitride, zinc oxide, barium titanate, lead titanate, potassium niobate, lithium tantalate, and lanthanum gallium silicate.

13. A piezoelectric vibrator comprising a substrate base plate and a plurality of piezoelectric elements according to any one of claims 1 to 12 provided on the substrate base plate.

14. An electronic device characterized by comprising the piezoelectric vibrator according to claim 13.

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