Actuator structure and liquid ejection apparatus including the same

Abstract

The invention discloses an actuator structure and a liquid spraying device comprising the same, the actuator structure comprises 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, and the upper electrode is connected to the bottom surface of the piezoelectric material. The piezoelectric material is a single crystal piezoelectric film material. The liquid spraying device comprises the actuator structure. According to the actuator structure and the liquid spraying device comprising the actuator structure, the piezoelectric material is processed and manufactured by using the single crystal piezoelectric film material, so that the single crystal piezoelectric film material can be processed by using a wet etching technology, the problems in a dry etching process are effectively avoided, the preparation precision of the actuator structure is ensured, and the manufacturing cost of the actuator structure is reduced. The stability of the actuator structure is improved, and the manufacturing cost of the actuator structure is reduced.

Description

Technical Field

[0001] The present invention relates to an actuator structure and a liquid ejection device including the same. Background Art

[0002] Compared with thermal bubble jet printing technology, piezoelectric inkjet printing technology has the advantages of long nozzle service life, wide range of printable material types, and precise control of ink droplet size, and has been widely used in the industrial printing and home printing markets.

[0003] The piezoelectric element in a piezoelectric inkjet printhead generally includes a lower electrode, an upper electrode, and a piezoelectric body layer, and the piezoelectric body layer is disposed between the lower electrode and the upper electrode. Currently, the piezoelectric material of the piezoelectric body layer is mostly prepared by polycrystalline materials. However, the processing of polycrystalline piezoelectric materials depends on dry etching technology. Although this technology can ensure the preparation accuracy, it will inevitably cause unnecessary etching of the substrate material, affecting the device performance; at the same time, the processing cost of dry etching technology is also relatively high. Summary of the Invention

[0004] 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 by polycrystalline materials, which will inevitably cause unnecessary etching of the substrate material, affecting the device performance and having a relatively high processing cost, and to provide an actuator structure and a liquid ejection device including the same.

[0005] The present invention solves the above technical problem by the following technical solutions:

[0006] 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, and the piezoelectric material is a single crystal piezoelectric thin film material.

[0007] 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.

[0008] Preferably, the actuator structure further includes a dielectric layer, and the dielectric layer is disposed between the lead layer and the lower electrode.

[0009] Preferably, the material of the dielectric layer is Al2O3, SiO2, resin, or lead zirconate titanate.

[0010] Preferably, the piezoelectric material is a lead zirconate titanate material, and the crystal plane orientation of the piezoelectric material is (100);

[0011] And / or, the thickness of the piezoelectric material is between 0.5 μm and 2 μm;

[0012] 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.

[0013] 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.

[0014] Preferably, the material of the buffer layer is zirconia.

[0015] 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;

[0016] 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.

[0017] Preferably, the material of the oxide electrode layer is strontium ruthenate.

[0018] A liquid ejection device, characterized in that it includes the actuator structure as described above.

[0019] 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.

[0020] The positive and progressive effects of the present invention are as follows:

[0021] For the actuator structure of the present invention and the liquid ejection device including the same, the piezoelectric material is processed and manufactured using 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

[0022] Figure 1 It is a schematic diagram of the internal structure of the liquid ejection device according to the embodiment of the present invention.

[0023] Figure 2 It is Figure 1 A partial enlarged schematic diagram of part A in

[0024] Description of the Reference Numerals:

[0025] Actuator structure 1

[0026] Diaphragm 11

[0027] Lower electrode 12

[0028] Piezoelectric material 13

[0029] Upper electrode 14

[0030] Lead layer 15

[0031] Dielectric layer 16

[0032] Buffer layer 17

[0033] Oxide electrode layer 18

[0034] Flow channel sheet 2

[0035] Pressure chamber 21

[0036] Nozzle sheet 3

[0037] Nozzle orifice 31

[0038] Package sheet 4 Detailed implementation manners

[0039] The present invention will be more clearly and completely described below by way of examples in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the examples thereby.

[0040] As Figure 1 and Figure 2 shown, an embodiment of the present invention discloses a liquid ejection device, which includes an actuator structure 1, a flow channel sheet 2, and a nozzle sheet 3. The actuator structure 1 and the nozzle sheet 3 are respectively disposed at the top and bottom of the flow channel sheet 2, and a pressure chamber 21 is formed between the actuator structure 1 and the flow channel sheet 2. The nozzle orifice 31 on the nozzle sheet 3 is in communication with the pressure chamber 21.

[0041] The actuator structure 1 includes a diaphragm 11, a piezoelectric material 13, a lower electrode 12, and an upper electrode 14. The top and bottom surfaces of the piezoelectric material 13 are respectively connected to the upper electrode 14 and the lower electrode 12. The diaphragm 11 is connected to the bottom surface of the lower electrode 12. The piezoelectric material 13 is a single crystal piezoelectric thin film material.

[0042] The actuator structure 1 is disposed on the flow channel sheet 2, and a pressure chamber 21 is formed between the inner wall surface of the actuator structure 1 and the inner wall surface of the flow channel sheet 2. The bottom surface of the lower electrode 12 is connected to the diaphragm 11. The piezoelectric material 13 is disposed between the upper electrode 14 and the lower electrode 12. The reverse piezoelectric effect of the piezoelectric material 13 is utilized to generate deformation and cause the vibration of the diaphragm 11, thereby realizing the pressure change in the pressure chamber 2. The ink in the pressure chamber 2 will be ejected through the nozzle orifice 31.

[0043] The piezoelectric material 13 is a single-crystal piezoelectric thin film material. The piezoelectric material 13 is fabricated using a single-crystal piezoelectric thin film material, enabling the processing of the single-crystal piezoelectric thin film material to use wet etching technology. This effectively avoids the problem of over-etching the lower electrode 12 and / or the vibration membrane 11 during the implementation of the dry etching process, ensures the preparation accuracy of the actuator structure 1, improves the stability of the actuator structure 1, and reduces the preparation cost of the actuator structure 1.

[0044] Among them, the piezoelectric material 13 is a 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.

[0045] The vibration membrane 11 is successively composed of silicon and silicon dioxide. The silicon and silicon dioxide in the vibration membrane 11 are arranged in layers and have a certain thickness. When the thickness of silicon is z1 and the thickness of silicon dioxide is z2, it satisfies 0 < z1 + z2 ≤ 1.5 μm, 0 < z1 ≤ 1.5 μm, and 0 ≤ z2 ≤ 1.5 μm.

[0046] In this embodiment, the lower electrode 12 is a common ground electrode, and the upper electrode 14 is a signal electrode. 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 the 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 disposed between the upper electrode 14 and the lower electrode 12, and the inverse piezoelectric effect of the piezoelectric material 13 is utilized to generate deformation and realize the vibration of the vibration membrane 11. A pressure chamber 21 is formed between the vibration 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 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.

[0047] The actuator structure 1 further includes a dielectric layer 16, and the dielectric layer 16 is disposed between the lead layer 15 and the lower electrode 12. The dielectric layer 16 has an isolation effect. By isolating between the lead layer 15 and the lower electrode 12 through the dielectric layer 16, the safety and stability of the actuator structure 1 are greatly improved.

[0048] Among them, the material selection range of the dielectric layer 16 is very wide. 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.

[0049] The actuator structure 1 further includes a buffer layer 17, which is located between the lower electrode 12 and the diaphragm 11 and is connected to the lower electrode 12 and the diaphragm 11. The main function of the buffer layer 17 is to reduce the stress between the diaphragm 11 and the lower electrode 12. At the same time, it is also used as an epitaxial layer of the diaphragm 11, which can inherit the crystal plane orientation of the diaphragm 11 and provide conditions for the growth of single crystal PZT. Among them, the material of the buffer layer 17 can be zirconia.

[0050] The actuator structure 1 further includes an oxide electrode layer 18, which can be located between the piezoelectric material 13 and the lower electrode 12 and is connected to the piezoelectric material 13 and the lower electrode 12. By arranging the oxide electrode layer 18 between the piezoelectric material 13 and the lower electrode 12, the atomic weight of the oxide electrode layer 18 is large, so that the diffusion of lead can be effectively prevented, and the safety and stability are further improved. Among them, the oxide electrode layer 18 can also be located between the upper electrode 14 and the piezoelectric material 13 and is connected to the upper electrode 14 and the piezoelectric material 13. The material of the oxide electrode layer 18 can be strontium ruthenate.

[0051] 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 within the packaging sheet 4. Among them, the packaging sheet 4 can be a silicon-based protective substrate. The bottom surface of the packaging sheet 4 has an inwardly recessed empty groove, through which contact with the upper electrode 14 and the piezoelectric material 13 can be avoided. 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 can also be an integrally formed structure, and in this instance, the open area is reserved in the form of a through hole.

[0052] 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, etc.

[0053] Although the specific implementation manners of the present invention have been described above, those skilled in the art should understand that this is only an example, and the protection scope of the present invention is defined by the appended claims. Without departing from the principles and essence of the present invention, those skilled in the art can make various changes or modifications to these implementation manners, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. An actuator structure, characterized in that, It includes a 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 diaphragm 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 outward and is used to connect to an external control area.

3. The actuator structure according to claim 2, wherein 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 claim 1, wherein, 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 diaphragm 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, 0 < z1 ≤ 1.5 μm, and 0 ≤ z2 ≤ 1.5 μm are satisfied.

6. The actuator structure according to claim 1, wherein, The actuator structure further includes a buffer layer, and the buffer layer is located between the lower electrode and the diaphragm and is connected to the lower electrode and the diaphragm.

7. The actuator structure according to claim 6, wherein The material of the buffer layer is zirconia.

8. The actuator structure according to claim 1, wherein, 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, wherein, The material of the oxide electrode layer is strontium ruthenate.

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

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