Liquid ejection head and liquid ejection device including same

Abstract

A liquid ejection head and a liquid ejection device including same. The liquid ejection head comprises an actuator (1), a flow channel piece (2) and a nozzle piece (3), wherein the actuator (1) comprises an upper electrode (14), a lower electrode (12), a piezoelectric material (13) and a vibrating diaphragm (11), the vibrating diaphragm (11) being connected to a top end of the flow channel piece (2), and a pressure cavity (4) being formed between the vibrating diaphragm (11) and the flow channel piece (2); a nozzle opening (31) is formed in the nozzle piece (3), the nozzle piece (3) is connected to a bottom end of the flow channel piece (2), and the nozzle opening (31) is in communication with the pressure cavity (4); and a top surface and a bottom surface of the piezoelectric material (13) are connected to the upper electrode (14) and the lower electrode (12), respectively, the lower electrode (12) being a common ground electrode and being connected to a top surface of the vibrating diaphragm (11) facing away from the pressure cavity (4), and the upper electrode (14) being a signal electrode and corresponding to the pressure cavity (4). The liquid ejection head has a simple preparation process and high preparation stability, thereby effectively reducing the production cost.

Description

Liquid ejection head and liquid ejection device including the same

[0001] This application claims the benefit of Chinese patent application No. 2023117763216, filed on December 22, 2023. This application incorporates the entirety of the aforementioned Chinese patent application. Technical Field

[0002] The present invention relates to a liquid ejection head 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] A piezoelectric inkjet print head is mainly composed of an actuator structure, a flow channel structure and a nozzle. The piezoelectric element in the actuator structure usually includes a lower electrode, an upper electrode, a piezoelectric layer and a vibration membrane. The piezoelectric layer is arranged between the lower electrode and the upper electrode. The vibration membrane is connected to the lower electrode. A pressure chamber is formed between the vibration membrane and the flow channel structure. The ink is ejected by the nozzle through the film deformation generated by the vibration membrane.

[0005] At present, since the print heads with higher printing resolution are prepared using MEMS technology, their upper electrode is a common ground electrode, the lower electrode is a signal electrode and is used to connect to the external control area, and the top surface of the piezoelectric layer needs to be processed to make grooves to install the upper electrode, and the end of the lower electrode needs to be covered by the piezoelectric layer and the vibration membrane, resulting in a more complicated preparation process, difficulty in improving the preparation accuracy, and affecting the performance of the device.

[0006] Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of the prior art such as the complicated preparation process of the piezoelectric inkjet print head, the difficulty in improving the preparation accuracy, and the impact on the device performance, and to provide a liquid ejection head and a liquid ejection device containing the same.

[0008] The present invention solves the above technical problems through the following technical solutions:

[0009] A liquid ejection head, characterized in that it includes an actuator, a flow channel plate and a nozzle plate, the actuator includes an upper electrode, a lower electrode, a piezoelectric material and a vibration membrane, the vibration membrane is connected to the top of the flow channel plate, and a pressure chamber is formed between the vibration membrane and the flow channel plate, the nozzle plate has a nozzle port, the nozzle plate is connected to the bottom end of the flow channel plate, and the nozzle port is connected to the pressure chamber, the top surface and bottom surface of the piezoelectric material are respectively connected to the upper electrode and the lower electrode, the lower electrode is a common ground electrode, the lower electrode is connected to the top surface of the vibration membrane facing away from the pressure chamber, the upper electrode is a signal electrode, and the upper electrode corresponds to the pressure chamber.

[0010] Preferably, the number of the pressure chambers is multiple, and the multiple pressure chambers are arranged at intervals along the width direction of the liquid ejection head and / or arranged in parallel along the length direction of the liquid ejection head;

[0011] And / or, the nozzle plate has a plurality of nozzle openings, and each of the pressure chambers is connected to at least one of the nozzle openings;

[0012] And / or, the number of the upper electrodes and the number of the piezoelectric materials are both multiple, the multiple upper electrodes are respectively arranged corresponding to the multiple pressure chambers, and the bottom surface of the lower electrode is entirely covered by the vibration membrane and the multiple pressure chambers.

[0013] Preferably, the top surface area of ​​the lower electrode is not less than the bottom surface area of ​​the piezoelectric material, and the outer edge of the lower electrode is exposed or flush with the side surface of the piezoelectric material;

[0014] And / or, the bottom surface area of ​​the upper electrode is not larger than the top surface area of ​​the piezoelectric material, and the outer edge of the upper electrode is not exposed on the side surface of the piezoelectric material.

[0015] Preferably, the actuator further includes a plurality of metal wires, one end of each metal wire is electrically connected to the upper electrode, the other end of each metal wire is connected to an external control area, and the plurality of metal wires are not connected to each other.

[0016] Preferably, the actuator further includes a dielectric layer, which is disposed between the metal wire and the lower electrode; preferably, the dielectric layer is made of Al2O3, SiO2, resin or lead zirconate titanate.

[0017] Preferably, the actuator further includes a buffer layer, which is located between the lower electrode and the vibration membrane and connected to the lower electrode and the vibration membrane; preferably, the buffer layer is made of zirconium dioxide.

[0018] Preferably, the actuator further includes an oxide electrode layer, which 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; preferably, the material of the oxide electrode layer is strontium ruthenate.

[0019] Preferably, the liquid ejection head further includes a sealing sheet, which is connected to the top of the actuator facing away from the flow channel sheet, and both the upper electrode and the piezoelectric material are located within the sealing sheet.

[0020] Preferably, the piezoelectric material is a single crystal piezoelectric thin film material;

[0021] and / or, the thickness of the piezoelectric material is between 0.5 μm and 2 μm;

[0022] 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 ≤ z <= 1.5 μm are satisfied.

[0023] A liquid ejection device, characterized in that it includes the liquid ejection head as described above.

[0024] Based on the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred examples of the present invention.

[0025] The positive and progressive effects of the present invention are as follows:

[0026] In the liquid ejection head of the present invention and the liquid ejection device including the same, ink enters the pressure chamber, and through the film deformation generated by the inverse piezoelectric effect, the ink is ejected from the nozzle. By using the lower electrode as a common ground electrode and the upper electrode as a signal electrode for external electrical connection, the design of the liquid ejection head is optimized, the manufacturing process is simplified, the manufacturing stability of the liquid ejection head is improved, and the production cost is effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a cross-sectional view of the liquid ejection head of the embodiment of the present invention along its width direction.

[0028] FIG. 2 is a partially enlarged schematic view of part A in FIG. 1.

[0029] FIG. 3 is a partial cross-sectional view of the liquid ejection head of the embodiment of the present invention along its length direction.

[0030] Explanation of Reference Numerals: Actuator 1 Vibration membrane 11 Lower electrode 12 Piezoelectric material 13 Upper electrode 14 Metal wire 15 Dielectric layer 16 Buffer layer 17 Oxide electrode layer 18 Flow channel plate 2 Nozzle plate 3 Nozzle port 31 Pressure chamber 4 Packaging plate 5 DETAILED DESCRIPTION

[0031] 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.

[0032] An embodiment of the present invention discloses a liquid ejection device, which includes a liquid ejection head. As shown in Figures 1, 2, and 3, the liquid ejection head includes an actuator 1, a flow channel plate 2, and a nozzle plate 3. The actuator 1 includes an upper electrode 14, a lower electrode 12, a piezoelectric material 13, and a vibrating membrane 11. The vibrating membrane 11 is connected to the top of the flow channel plate 2, and a pressure chamber 4 is formed between the vibrating membrane 11 and the flow channel plate 2. The nozzle plate 3 has a nozzle opening 31, which is connected to the bottom of the flow channel plate 2, and the nozzle opening 31 is connected to the pressure chamber 4. The top and bottom surfaces of the piezoelectric material 13 are respectively connected to the upper electrode 14 and the lower electrode 12. The lower electrode 12 is a common ground electrode and is connected to the top surface of the vibrating membrane 11 facing away from the pressure chamber 4. The upper electrode 14 is a signal electrode and corresponds to the pressure chamber 4.

[0033] The lower electrode 12 is a common ground electrode, and the upper electrode 14 is a signal electrode for external electrical connection. 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 4 is formed between the vibrating membrane 11 and the flow channel plate 2. The upper electrode 14 corresponds to the pressure chamber 4, thereby realizing the pressure change in the pressure chamber 4. The flow channel 2 has a flow channel. The ink will enter the flow channel plate 2 from one end of the flow channel. The flow channel is connected to the pressure chamber 4, so that the ink will enter the pressure chamber 4 and be ejected from the nozzle opening 31 through the film deformation caused by the inverse piezoelectric effect. Since the lower electrode 12 is a common ground electrode and the upper electrode 14 is a signal electrode for external electrical connection, the design of the liquid ejection head is optimized, the preparation process is simplified, and the preparation stability of the liquid ejection head is improved, effectively reducing the production cost.

[0034] In this embodiment, the top surface area of ​​the lower electrode 12 is not less than the bottom surface area of ​​the piezoelectric material 13, and the outer edge of the lower electrode 12 is exposed or flush with the side surface of the piezoelectric material 13, which facilitates the installation of the piezoelectric material 13 on the lower electrode 12. The lower electrode 12 is entirely covered by the pressure chamber 4. The outer edge of the lower electrode 12 is flush with the outer edge of the vibrating membrane 11.

[0035] The bottom surface area of ​​the upper electrode 14 is no larger than the top surface area of ​​the piezoelectric material 13, and the outer edge of the upper electrode 14 is not exposed on the side of the piezoelectric material 13, so that the upper electrode 14 is easily installed on the piezoelectric material 13. Preferably, the outer edge of the piezoelectric material 13 is exposed on the side of the upper electrode 14.

[0036] In this embodiment, there are multiple pressure chambers 4. These multiple pressure chambers 4 can be spaced apart along the width of the liquid ejection head, or arranged in parallel along the length of the liquid ejection head. Preferably, the flow channel plate 2 includes multiple flow channels, one end of each of which is connected to the corresponding pressure chambers 4 within the actuator 1, and the other end of each of the multiple flow channels is connected to a shared liquid supply device, thereby achieving a more compact overall structure and effectively reducing costs.

[0037] The nozzle plate 3 has multiple nozzle openings 31, and each pressure chamber 4 is connected to at least one nozzle opening 31. The nozzle plate 3 is connected to the bottom of the flow channel plate 2, and the multiple pressure chambers 4 will eject ink through the nozzle openings 31 respectively.

[0038] In this embodiment, there are multiple upper electrodes 14 and piezoelectric materials 13. The multiple upper electrodes 14 are respectively arranged corresponding to the multiple pressure chambers 4, and the bottom surface of the lower electrode 12 is entirely covered by the vibrating membrane 11 and the multiple pressure chambers 4. The multiple upper electrodes 14 and the multiple pressure chambers 4 are relatively independent and respectively arranged in correspondence. The multiple upper electrodes 14 and the piezoelectric materials 13 are respectively used to control the multiple pressure chambers 4 and to eject ink, thereby achieving independent control of each pressure chamber 4. Among them, there is only one lower electrode 12, and the bottom surface of the one lower electrode 12 is entirely covered by the vibrating membrane 11 and the multiple pressure chambers 4, so that the multiple upper electrodes 14 share a single lower electrode 12, which simplifies the preparation process and effectively reduces production costs.

[0039] The liquid ejection head also includes an encapsulation sheet 5, which is connected to the top of the actuator 1 facing away from the flow channel sheet 2. The upper electrode 14 and the piezoelectric material 13 are both located within the encapsulation sheet 5. The encapsulation sheet 5 is connected to the actuator 1 and is used to encapsulate and protect the upper electrode 14 and the piezoelectric material 13, greatly improving the safety and stability of the liquid ejection head.

[0040] Among them, the encapsulation sheet 5 can be a silicon-based protective substrate. The bottom surface of the encapsulation sheet 5 has an inwardly recessed groove, which can avoid contact with the upper electrode 14 and the piezoelectric material 13. The encapsulation sheet 5 can be bonded to the lower electrode 12 and / or the metal wire 15 using an adhesive. An open area is provided between the two encapsulation sheets 5, and the metal wire 15 will be exposed in the open area and connected to the control area. In other embodiments, the two encapsulation sheets 5 can also be an integrally molded structure, in which case the open area is retained in the form of a through hole.

[0041] In this embodiment, the piezoelectric material 13 is a single crystal piezoelectric thin film material. The piezoelectric material 13 of this invention patent is fabricated using a single crystal piezoelectric thin film material. Since wet etching technology can be used in the processing of the single crystal piezoelectric thin film material, the over-etching problem of dry etching is effectively avoided, ensuring the manufacturing precision, improving the performance of the liquid ejection head, and reducing the manufacturing cost of the liquid ejection head. At the same time, the design of the piezoelectric material 13 as a single crystal piezoelectric thin film material is optimized for the adopted processing technology, a new processing scheme for the piezoelectric material 13 is proposed, and the stability of the liquid ejection head is improved. Among them, the main component of the single crystal piezoelectric thin film material is lead zirconate titanate, and its crystal plane orientation is (100). Preferably, the thickness of the piezoelectric material 13 is between 0.5 μm and 2 μm.

[0042] The diaphragm 11 is composed of silicon and silicon dioxide in sequence. The silicon and silicon dioxide in the diaphragm 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, 0 < z1 + z2 ≤ 1.5 μm, 0 < z1 ≤ 1.5 μm, and 0 ≤ z2 ≤ 1.5 μm are satisfied.

[0043] The liquid ejection head further includes a plurality of metal wires 15. One end of the metal wire 15 is electrically connected to the upper electrode 14, and the other end of the metal wire 15 is connected to the external control area, and the plurality of metal wires 15 are not connected to each other. The upper electrode 14 is led out via the metal wire 15 and connected to the control area. The control area is composed of cross-arranged metal wires 15, and the metal wires 15 are not connected to each other, so as to achieve separate control of the plurality of upper electrodes 14, and the safety and stability are high. Among them, the metal wire 15 can include at least one of gold, silver, copper, platinum, aluminum, titanium, chromium, and nickel.

[0044] The actuator 1 further includes a dielectric layer 16, and the dielectric layer 16 is disposed between the metal wire 15 and the lower electrode 12. The dielectric layer 16 has an isolation effect. The metal wire 15 and the lower electrode 12 are isolated through the dielectric layer 16, greatly improving the safety and stability of the liquid ejection head. 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 metal wire 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.

[0045] Actuator 1 also includes a buffer layer 17, which is located between and connected to lower electrode 12 and diaphragm 11. Buffer layer 17 primarily reduces stress between diaphragm 11 and lower electrode 12. It also serves as an epitaxial layer for diaphragm 11, inheriting the crystal orientation of diaphragm 11 and facilitating the growth of single-crystal PZT. Buffer layer 17 can be made of zirconium dioxide.

[0046] Actuator 1 also includes an oxide electrode layer 18, which is located between piezoelectric material 13 and lower electrode 12 and is connected to both. By positioning oxide electrode layer 18 between piezoelectric material 13 and lower electrode 12, the oxide electrode layer 18 has a large atomic weight, which effectively prevents the diffusion of lead, further improving safety and stability. The oxide electrode layer 18 can also be located between upper electrode 14 and piezoelectric material 13 and connected to both. The oxide electrode layer 18 can be made of strontium ruthenate.

[0047] The liquid ejection device in the embodiment of the present invention can be applied to printing equipment, and can also be applied to various equipment fields such as semiconductor manufacturing equipment, battery manufacturing equipment, etc.

[0048] 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. A liquid ejection head, characterized in that: It includes an actuator, a flow channel plate and a nozzle plate. The actuator includes an upper electrode, a lower electrode, a piezoelectric material and a vibration membrane. The vibration membrane is connected to the top of the flow channel plate, and a pressure chamber is formed between the vibration membrane and the flow channel plate. The nozzle plate has a nozzle port, and the nozzle plate is connected to the bottom end of the flow channel plate, and the nozzle port is communicated with the pressure chamber. The top surface and bottom surface of the piezoelectric material are respectively connected to the upper electrode and the lower electrode, and the lower electrode is a common ground electrode. The lower electrode is connected to the top surface of the vibration membrane facing away from the pressure chamber. The upper electrode is a signal electrode, and the upper electrode corresponds to the pressure chamber.

2. The liquid ejection head according to claim 1, wherein: The number of the pressure chambers is multiple, and the multiple pressure chambers are arranged at intervals along the width direction of the liquid ejection head and / or arranged in parallel along the length direction of the liquid ejection head; And / or, the nozzle plate has a plurality of nozzle openings, and each of the pressure chambers is connected to at least one of the nozzle openings; And / or, the number of the upper electrode and the number of the piezoelectric material are both multiple, the multiple upper electrodes are respectively arranged corresponding to the multiple pressure chambers, and the bottom surface of the lower electrode is entirely covered by the vibration membrane and the multiple pressure chambers.

3. The liquid ejection head according to claim 1 or 2, wherein: The top surface area of ​​the lower electrode is not less than the bottom surface area of ​​the piezoelectric material, and the outer edge of the lower electrode is exposed or flush with the side surface of the piezoelectric material; And / or, the bottom surface area of ​​the upper electrode is not larger than the top surface area of ​​the piezoelectric material, and the outer edge of the upper electrode is not exposed on the side surface of the piezoelectric material.

4. The liquid ejection head according to any one of claims 1 to 3, characterized in that: The actuator further comprises a plurality of metal wires, one end of each of which is electrically connected to the upper electrode, the other end of each of which is connected to an external control area, and the plurality of metal wires are not connected to each other.

5. The liquid ejection head according to claim 4, wherein: The actuator further includes a dielectric layer, and the dielectric layer is disposed between the metal wire and the lower electrode; preferably, the dielectric layer is made of Al2O3, SiO2, resin or lead zirconate titanate.

6. The liquid ejection head according to any one of claims 1 to 5, characterized in that: The actuator further includes a buffer layer, which is located between the lower electrode and the vibration membrane and connected to the lower electrode and the vibration membrane; preferably, the buffer layer is made of zirconium dioxide.

7. The liquid ejection head according to any one of claims 1 to 6, characterized in that: The actuator also includes an oxide electrode layer, which is located between the piezoelectric material and the lower electrode and 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 connected to the upper electrode and the piezoelectric material; preferably, the material of the oxide electrode layer is strontium ruthenate.

8. The liquid ejection head according to any one of claims 1 to 7, characterized in that: The liquid ejection head further comprises a packaging sheet, which is connected to a top end of the actuator facing away from the flow channel sheet, and the upper electrode and the piezoelectric material are both located in the packaging sheet.

9. The liquid ejection head according to any one of claims 1 to 8, characterized in that: The piezoelectric material is a single crystal piezoelectric thin film material; 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, it satisfies 0 < z1 + z2 ≤ 1.5 μm, and 0 < z1 ≤ 1.5 μm, 0 ≤ z2 ≤ 1.5 μm.

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

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