Actuator structure and liquid ejection device comprising same

Abstract

Disclosed in the present invention are an actuator structure and a liquid ejection device comprising same. The actuator structure comprises a vibrating diaphragm, a piezoelectric material, a lower electrode, and an upper electrode. The top surface and the bottom surface of the piezoelectric material are respectively connected to the upper electrode and the lower electrode. The vibrating diaphragm is connected to the bottom surface of the lower electrode. The piezoelectric material is a single crystal piezoelectric thin film material. The liquid ejection device comprises the described actuator structure. According to the actuator structure and the liquid ejection device comprising same in the present invention, the piezoelectric material is fabricated from a single crystal piezoelectric thin film material, and wet etching technology can be used for processing the single crystal piezoelectric thin film material, thereby effectively avoiding problems occurred in dry etching, ensuring the manufacturing precision of the actuator structure, improving the stability of the actuator structure, and reducing the manufacturing costs of the actuator structure.

Description

Actuator structure and liquid ejection device including the same

[0001] This application claims priority to Chinese patent application No. 2023117767382, filed on December 22, 2023. This application incorporates the entirety of the aforementioned Chinese patent application. Technical Field

[0002] The present invention relates to an actuator structure and a liquid ejection device comprising the same. Background Art

[0003] Compared with thermal inkjet printing technology, piezoelectric inkjet printing technology has the advantages of long nozzle life, a wide range of printing materials, and precise control of ink droplet size. It has been widely used in the industrial printing and home printing markets.

[0004] The piezoelectric element in a piezoelectric inkjet printhead typically consists of a lower electrode, an upper electrode, and a piezoelectric layer, which is positioned between the lower and upper electrodes. Currently, the piezoelectric material for the piezoelectric layer is mostly made of polycrystalline material. However, processing polycrystalline piezoelectric material relies on dry etching technology. While this technique ensures fabrication accuracy, it inevitably causes unnecessary etching of the substrate material, affecting device performance. Furthermore, dry etching technology is also costly.

[0005] Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects in the prior art that piezoelectric materials are mostly prepared from polycrystalline materials, which inevitably causes unnecessary etching to the substrate material, affects device performance, and has high processing costs. An actuator structure and a liquid ejection device containing the same are provided.

[0007] The present invention solves the above technical problems through the following technical solutions:

[0008] An actuator structure is characterized in that it includes a vibration membrane, a piezoelectric material, a lower electrode and an upper electrode, the top surface and bottom surface of the piezoelectric material are respectively connected to the upper electrode and the lower electrode, the vibration membrane is connected to the bottom surface of the lower electrode, and the piezoelectric material is a single crystal piezoelectric thin film material.

[0009] Preferably, the lower electrode is a common ground electrode, the upper electrode is a signal electrode, and the actuator structure further includes a lead layer, one end of the lead layer is electrically connected to the upper electrode, and the other end of the lead layer extends outward and is used to connect to an external control area.

[0010] Preferably, the actuator structure further includes a dielectric layer, and the dielectric layer is arranged between the lead layer and the lower electrode.

[0011] Preferably, the dielectric layer is made of Al2O3, SiO2, resin or lead zirconate titanate.

[0012] Preferably, the piezoelectric material is a lead zirconate titanate material, and the crystal plane orientation of the piezoelectric material is (100);

[0013] And / or, the thickness of the piezoelectric material is between 0.5 μm and 2 μm;

[0014] And / or, the vibration film is composed of silicon and silicon dioxide in sequence. When the thickness of the silicon is z1 and the thickness of the silicon dioxide is z2, 0 < z1 + z2 ≤ 1.5 μm, 0 < z1 ≤ 1.5 μm, and 0 ≤ z2 ≤ 1.5 μm are satisfied.

[0015] Preferably, the actuator structure further includes a buffer layer, and the buffer layer is located between the lower electrode and the vibration film and is connected to the lower electrode and the vibration film.

[0016] Preferably, the buffer layer is made of zirconia.

[0017] Preferably, the actuator structure further includes an oxide electrode layer, and the oxide electrode layer is located between the piezoelectric material and the lower electrode and is connected to the piezoelectric material and the lower electrode;

[0018] And / or, the oxide electrode layer is located between the upper electrode and the piezoelectric material and is connected to the upper electrode and the piezoelectric material.

[0019] Preferably, the oxide electrode layer is made of strontium ruthenate.

[0020] A liquid ejection device, characterized in that it includes the actuator structure as described above.

[0021] On the basis of conforming to the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred examples of the present invention.

[0022] The positive and progressive effects of the present invention are as follows:

[0023] For the actuator structure of the present invention and the liquid ejection device including the same, the piezoelectric material is made by processing a single crystal piezoelectric thin film material, so that the processing of the single crystal piezoelectric thin film material can use wet etching technology, thereby effectively avoiding the problems in the dry etching process, ensuring the preparation accuracy of the actuator structure, improving the stability of the actuator structure, and reducing the preparation cost of the actuator structure. Description of the Drawings

[0024] FIG. 1 is a schematic internal structure diagram of the liquid ejection device according to an embodiment of the present invention.

[0025] FIG2 is a partial enlarged schematic diagram of portion A in FIG1 .

[0026] Explanation of Reference Numerals: Actuator structure 1 Vibration membrane 11 Lower electrode 12 Piezoelectric material 13 Upper electrode 14 Lead layer 15 Dielectric layer 16 Buffer layer 17 Oxide electrode layer 18 Flow channel plate 2 Pressure chamber 21 Nozzle plate 3 Nozzle opening 31 Packaging plate 4 DETAILED DESCRIPTION

[0027] The present invention will be described more clearly and completely below by way of embodiments in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the embodiments.

[0028] As shown in Figures 1 and 2, an embodiment of the present invention discloses a liquid ejection device, which includes an actuator structure 1, a flow channel plate 2 and a nozzle plate 3. The actuator structure 1 and the nozzle plate 3 are respectively arranged at the top and bottom of the flow channel plate 2, and a pressure chamber 21 is formed between the actuator structure 1 and the flow channel plate 2. The nozzle port 31 on the nozzle plate 3 is connected to the pressure chamber 21.

[0029] The actuator structure 1 includes a vibration membrane 11, a piezoelectric material 13, a lower electrode 12 and an upper electrode 14. The top surface and bottom surface of the piezoelectric material 13 are respectively connected to the upper electrode 14 and the lower electrode 12. The vibration membrane 11 is connected to the bottom surface of the lower electrode 12. The piezoelectric material 13 is a single crystal piezoelectric thin film material.

[0030] Actuator structure 1 is mounted on flow channel plate 2, forming a pressure chamber 21 between the inner wall of actuator structure 1 and the inner wall of flow channel plate 2. The bottom surface of lower electrode 12 is connected to diaphragm 11, and piezoelectric material 13 is positioned between upper electrode 14 and lower electrode 12. The inverse piezoelectric effect of piezoelectric material 13 causes deformation and vibration of diaphragm 11, thereby changing the pressure within pressure chamber 2. The ink in pressure chamber 2 is ejected through nozzle opening 31.

[0031] The piezoelectric material 13 is a single crystal piezoelectric thin film material. The piezoelectric material 13 is made of a single crystal piezoelectric thin film material, so that the processing of the single crystal piezoelectric thin film material can use wet etching technology, thereby effectively avoiding the problem of over-etching of the lower electrode 12 and / or the vibration membrane 11 during the implementation of the dry etching process, ensuring the preparation accuracy of the actuator structure 1, improving the stability of the actuator structure 1, and reducing the preparation cost of the actuator structure 1.

[0032] The piezoelectric material 13 is lead zirconate titanate material, and the crystal plane orientation of the piezoelectric material 13 is (100), which improves the performance of the actuator structure 1. Preferably, the thickness of the piezoelectric material 13 is between 0.5 μm and 2 μm.

[0033] The vibrating membrane 11 is composed of silicon and silicon dioxide in sequence. The silicon and silicon dioxide in the vibrating membrane 11 are arranged in layers and have a certain thickness. When the thickness of the silicon is z1 and the thickness of the silicon dioxide is z2, 0 < z1 + z2 ≤ 1.5 μm, 0 < z1 ≤ 1.5 μm, and 0 ≤ z2 ≤ 1.5 μm are satisfied.

[0034] In this embodiment, the lower electrode 12 is a common ground electrode, the upper electrode 14 is a signal electrode, and the actuator structure 1 further includes a lead layer 15. One end of the lead layer 15 is electrically connected to the upper electrode 14, and the other end of the lead layer 15 extends outward and is used to connect to an external control area. The lower electrode 12 is a common ground electrode, and the upper electrode 14 is led out via the lead layer 15 and connected to the external control area, which is very convenient for installation and connection and has high stability. At the same time, the piezoelectric material 13 is arranged between the upper electrode 14 and the lower electrode 12. The inverse piezoelectric effect of the piezoelectric material 13 is used to generate deformation and realize the vibration of the vibrating membrane 11. A pressure chamber 21 is formed between the vibrating membrane 11 and the flow channel plate 2. By corresponding the upper electrode 14 to the pressure chamber 21, the pressure change in the pressure chamber 21 is realized. The above-mentioned structural design optimizes the design of the actuator structure 1, simplifies the preparation process, improves the preparation stability of the actuator structure 1, and effectively reduces the production cost.

[0035] The actuator structure 1 further includes a dielectric layer 16, and the dielectric layer 16 is arranged between the lead layer 15 and the lower electrode 12. The dielectric layer 16 has an isolation function. The lead layer 15 and the lower electrode 12 are isolated through the dielectric layer 16, which greatly improves the safety and stability of the actuator structure 1.

[0036] Among them, the material selection range of the dielectric layer 16 is very large. The material of the dielectric layer 16 can be Al2O3, SiO2, resin, lead zirconate titanate, etc. The lead layer 15 located in the external control area can also use a dielectric layer as a substrate. The dielectric layer is an oxide, and the dielectric layer can include at least one of silicon, aluminum, zirconium, titanium, and lead.

[0037] The actuator structure 1 further includes a buffer layer 17, and the buffer layer 17 is located between the lower electrode 12 and the vibrating membrane 11 and is connected to the lower electrode 12 and the vibrating membrane 11. The main function of the buffer layer 17 is to reduce the stress between the vibrating membrane 11 and the lower electrode 12. At the same time, it is also used as an epitaxial layer of the vibrating membrane 11, and can inherit the crystal plane orientation of the vibrating membrane 11, providing conditions for the growth of single crystal PZT. Among them, the material of the buffer layer 17 can be zirconium dioxide.

[0038] The actuator structure 1 also includes an oxide electrode layer 18, which can be located between the piezoelectric material 13 and the lower electrode 12 and connected thereto. By disposing the oxide electrode layer 18 between the piezoelectric material 13 and the lower electrode 12, the oxide electrode layer 18 has a large atomic weight, which can effectively prevent the diffusion of lead, further improving safety and stability. The oxide electrode layer 18 can also be located between the upper electrode 14 and the piezoelectric material 13 and connected thereto. The material of the oxide electrode layer 18 can be strontium ruthenate.

[0039] The liquid ejection device may further include a packaging sheet 4, which is connected to the top of the actuator structure 1 facing away from the flow channel sheet 2. Specifically, the packaging sheet 4 is connected to the lower electrode 12 and / or the lead layer 15, and the upper electrode 14 and the piezoelectric material 13 are both located in the packaging sheet 4. The packaging sheet 4 may be a silicon-based protective substrate. The bottom surface of the packaging sheet 4 has an inwardly recessed groove, which can avoid contact with the upper electrode 14 and the piezoelectric material 13. The packaging sheet 4 can be bonded to the lower electrode 12 using an adhesive. An open area is provided between the two packaging sheets 4, and the lead layer 15 will be exposed in the open area and connected to the external control area. In other embodiments, the two packaging sheets 4 may also be an integrally formed structure, in which the open area is retained in the form of a through hole.

[0040] The liquid ejection device in the embodiment of the present invention can be applied to an inkjet print head, and can also be applied to a valve body, a pump body, and the like.

[0041] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. An actuator structure, characterized in that: It includes a vibrating membrane, a piezoelectric material, a lower electrode and an upper electrode. The top surface and the bottom surface of the piezoelectric material are respectively connected to the upper electrode and the lower electrode. The vibrating membrane is connected to the bottom surface of the lower electrode. The piezoelectric material is a single crystal piezoelectric thin film material.

2. The actuator structure according to claim 1, characterized in that: The lower electrode is a common ground electrode, and the upper electrode is a signal electrode. The actuator structure further includes a lead layer. One end of the lead layer is electrically connected to the upper electrode, and the other end of the lead layer extends outwards and is used to connect to an external control area.

3. The actuator structure according to claim 2, characterized in that: The actuator structure further includes a dielectric layer, and the dielectric layer is disposed between the lead layer and the lower electrode.

4. The actuator structure according to claim 3, characterized in that: The material of the dielectric layer is Al2O3, SiO2, resin or lead zirconate titanate.

5. The actuator structure according to any one of claims 1 to 4, characterized in that: The piezoelectric material is a lead zirconate titanate material, and the crystal plane orientation of the piezoelectric material is 100; and / or, the thickness of the piezoelectric material is between 0.5 μm and 2 μm; and / or, the vibrating membrane is successively composed of silicon and silicon dioxide. When the thickness of the silicon is z1 and the thickness of the silicon dioxide is z2, 0 < z1 + z2 ≤ 1.5 μm, and 0 < z1 ≤ 1.5 μm, 0 ≤ z2 ≤ 1.5 μm are satisfied.

6. The actuator structure according to any one of claims 1 to 5, characterized in that: The actuator structure further includes a buffer layer, and the buffer layer is located between the lower electrode and the vibrating membrane and is connected to the lower electrode and the vibrating membrane.

7. The actuator structure according to claim 6, characterized in that: The material of the buffer layer is zirconium dioxide.

8. The actuator structure according to any one of claims 1 to 7, characterized in that: The actuator structure further includes an oxide electrode layer, and the oxide electrode layer is located between the piezoelectric material and the lower electrode and is connected to the piezoelectric material and the lower electrode; and / or, the oxide electrode layer is located between the upper electrode and the piezoelectric material and is connected to the upper electrode and the piezoelectric material.

9. The actuator structure according to claim 8, characterized in that: The material of the oxide electrode layer is strontium ruthenate.

10. A liquid ejection device, characterized in that: It includes the actuator structure according to any one of claims 1-9.

Images