Liquid ejection head and liquid ejection apparatus including same

Abstract

A liquid ejection head includes an actuator, a flow channel sheet, and a nozzle sheet, the actuator including an upper electrode, a lower electrode, a piezoelectric material, and a vibration membrane connected to a tip of the flow channel sheet, the piezoelectric material being disposed on the upper electrode, the piezoelectric material being disposed on the lower electrode, and the vibration membrane being disposed on the nozzle sheet. A pressure cavity is formed between the vibrating membrane and the flow channel piece, a nozzle opening is formed in the nozzle piece, the nozzle piece is connected to the bottom end of the flow channel piece, the nozzle opening is communicated with the pressure cavity, the top face and the bottom face of the piezoelectric material are connected to the upper electrode and the lower electrode respectively, and the piezoelectric material is arranged between the upper electrode and the lower electrode. The lower electrode is a common ground electrode, the lower electrode is connected to the top surface, back on to the pressure cavity, in the vibrating diaphragm, and the upper electrode is a signal electrode and corresponds to the pressure cavity. The preparation process is simple, the preparation stability of the liquid ejection head is improved, and the production cost is effectively reduced.

Description

Technical Field

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

[0002] Compared with thermal inkjet 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] A piezoelectric inkjet print head mainly consists of an actuator structure, a flow channel structure, and a nozzle. Among them, the piezoelectric element in the actuator structure usually includes a lower electrode, an upper electrode, a piezoelectric layer, and a vibration film. The piezoelectric layer is disposed between the lower electrode and the upper electrode, the vibration film is connected to the lower electrode, and a pressure chamber is formed between the vibration film and the flow channel structure. Ink is ejected through the nozzle due to the film deformation generated by the vibration film.

[0004] Currently, since nozzles with high printing resolution are fabricated using MEMS technology, its upper electrode is a common ground electrode, the lower electrode is a signal electrode and is used to connect to an external control area, and grooves need to be machined on the top surface of the piezoelectric layer to install the upper electrode, and the end of the lower electrode needs to be covered by the piezoelectric layer and the vibration film, resulting in a relatively complex manufacturing process, difficulty in improving manufacturing precision, and affecting device performance. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects in the prior art that the manufacturing process of the piezoelectric inkjet print head is relatively complex, it is difficult to improve the manufacturing precision, and it affects device performance, and to provide a liquid ejection head and a liquid ejection device including the same.

[0006] The present invention solves the above technical problem by the following technical solutions:

[0007] 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 film. The vibration film is connected to the top end of the flow channel plate, and a pressure chamber is formed between the vibration film and the flow channel plate. The nozzle plate has a nozzle opening, the nozzle plate is connected to the bottom end of the flow channel plate, and the nozzle opening is communicated with the pressure chamber. The top surface and the 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 film facing away from the pressure chamber, the upper electrode is a signal electrode, and the upper electrode corresponds to the pressure chamber.

[0008] Preferably, the number of the pressure chambers is plural, and the plural pressure chambers are arranged at intervals in the width direction of the liquid ejection head and / or arranged side by side in the length direction of the liquid ejection head;

[0009] And / or, the nozzle plate has a plurality of nozzle openings, and each of the pressure chambers communicates with at least one of the nozzle openings;

[0010] And / or, the number of the upper electrodes and the piezoelectric material is plural, the plural upper electrodes are respectively arranged corresponding to the plural pressure chambers, and the bottom surface of the lower electrode entirely covers the vibration film and the plural pressure chambers.

[0011] 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;

[0012] And / or, the bottom surface area of the upper electrode is not greater than the top surface area of the piezoelectric material, and the outer edge of the upper electrode is not exposed from the side surface of the piezoelectric material.

[0013] 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 plural metal wires are not connected to each other.

[0014] Preferably, 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.

[0015] Preferably, the actuator 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; preferably, the buffer layer is made of zirconia.

[0016] Preferably, the actuator 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; preferably, the oxide electrode layer is made of strontium ruthenate.

[0017] Preferably, the liquid ejection head further includes a packaging sheet, the packaging sheet is connected to the top end of the actuator facing away from the flow channel sheet, and both the upper electrode and the piezoelectric material are located within the packaging sheet.

[0018] Preferably, the piezoelectric material is a single crystal piezoelectric thin film material;

[0019] And / or, the thickness of the piezoelectric material is between 0.5 μm and 2 μm;

[0020] 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.

[0021] A liquid ejection device, characterized in that it includes the liquid ejection head as described above.

[0022] 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.

[0023] The positive and progressive effects of the present invention are as follows:

[0024] For 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 orifice; by using the lower electrode as the common ground electrode and the upper electrode as the 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

[0025] Figure 1 It is a cross-sectional view of the liquid ejection head of the embodiment of the present invention along its width direction.

[0026] Figure 2 is Figure 1 A partial enlarged schematic view of part A in

[0027] Figure 3 It is a partial cross-sectional view of the liquid ejection head of the embodiment of the present invention along its length direction.

[0028] Description of the Reference Numerals:

[0029] Actuator 1

[0030] Vibration film 11

[0031] Lower electrode 12

[0032] Piezoelectric material 13

[0033] Upper electrode 14

[0034] Metal wire 15

[0035] Dielectric layer 16

[0036] Buffer layer 17

[0037] Oxide electrode layer 18

[0038] Flow channel sheet 2

[0039] Nozzle sheet 3

[0040] Nozzle orifice 31

[0041] Pressure chamber 4

[0042] Encapsulation sheet 5 Specific embodiments

[0043] The present invention will be more clearly and completely described below by way of embodiments in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the embodiments thereby.

[0044] An embodiment of the present invention discloses a liquid ejection device, and the liquid ejection device includes a liquid ejection head. As Figure 1 , Figure 2 and Figure 3 shown, the liquid ejection head includes an actuator 1, a flow channel sheet 2, and a nozzle sheet 3. The actuator 1 includes an upper electrode 14, a lower electrode 12, a piezoelectric material 13, and a vibration film 11. The vibration film 11 is connected to the top end of the flow channel sheet 2, and a pressure chamber 4 is formed between the vibration film 11 and the flow channel sheet 2. The nozzle sheet 3 has a nozzle orifice 31. The nozzle sheet 3 is connected to the bottom end of the flow channel sheet 2, and the nozzle orifice 31 communicates with the pressure chamber 4. The top surface and the bottom surface 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 the lower electrode 12 is connected to the top surface of the vibration film 11 facing away from the pressure chamber 4. The upper electrode 14 is a signal electrode, and the upper electrode 14 corresponds to the pressure chamber 4.

[0045] 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 disposed between the upper electrode 14 and the lower electrode 12. The inverse piezoelectric effect of the piezoelectric material 13 is utilized to generate deformation and realize the vibration of the vibration film 11. A pressure chamber 4 is formed between the vibration film 11 and the flow channel sheet 2. By the upper electrode 14 corresponding to the pressure chamber 4, the pressure change in the pressure chamber 4 is thus realized. The flow channel sheet 2 has a flow channel, and ink will enter the flow channel sheet 2 from one end of the flow channel. The flow channel communicates with the pressure chamber 4, so that the ink will enter the pressure chamber 4, and through the film deformation generated by the inverse piezoelectric effect, the ink is ejected from the nozzle orifice 31. 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 simple, the preparation stability of the liquid ejection head is improved, and the production cost is effectively reduced.

[0046] 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, facilitating the installation of the piezoelectric material 13 on the lower electrode 12. Among them, the lower electrode 12 entirely covers the pressure chamber 4. The outer edge of the lower electrode 12 is flush with the outer edge of the vibration film 11.

[0047] The bottom surface area of the upper electrode 14 is not greater than the top surface area of the piezoelectric material 13, and the outer edge of the upper electrode 14 is not exposed beyond the side surface of the piezoelectric material 13, facilitating the installation of the upper electrode 14 on the piezoelectric material 13. Preferably, the outer edge of the piezoelectric material 13 is exposed beyond the side surface of the upper electrode 14.

[0048] In this embodiment, the number of pressure chambers 4 is multiple. The multiple pressure chambers 4 can be arranged at intervals along the width direction of the liquid ejection head, or the multiple pressure chambers 4 can be arranged side by side along the length direction of the liquid ejection head. Preferably, the flow channel sheet 2 has multiple flow channels. One ends of the multiple flow channels respectively communicate with the multiple pressure chambers 4 in the actuator 1, and the other ends of the multiple flow channels communicate with a common liquid supply device, making the overall structure more compact and effectively reducing costs.

[0049] The nozzle sheet 3 has multiple nozzle openings 31, and each pressure chamber 4 is connected to at least one nozzle opening 31. The nozzle sheet 3 is connected to the bottom of the flow channel sheet 2, and the multiple pressure chambers 4 will eject ink through the nozzle openings 31 respectively.

[0050] In this embodiment, the number of upper electrodes 14 and piezoelectric materials 13 is multiple. The multiple upper electrodes 14 and the multiple pressure chambers 4 are respectively arranged in correspondence. The bottom surface of the lower electrode 12 entirely covers the vibration film 11 and the multiple pressure chambers 4. The multiple upper electrodes 14 and the multiple pressure chambers 4 are relatively independently and respectively arranged. The multiple upper electrodes 14 and piezoelectric materials 13 are respectively used to control the multiple pressure chambers 4 and to eject ink, realizing the individual control of each pressure chamber 4. Among them, the number of lower electrodes 12 is one. The bottom surface of one lower electrode 12 entirely covers the vibration film 11 and the multiple pressure chambers 4, enabling the multiple upper electrodes 14 to share one lower electrode 12, simplifying the manufacturing process and effectively reducing the production cost.

[0051] The liquid ejection head further includes a packaging sheet 5. The packaging sheet 5 is connected to the top end of the actuator 1 facing away from the flow channel sheet 2, and both the upper electrode 14 and the piezoelectric material 13 are located within the packaging sheet 5. The packaging sheet 5 is connected to the actuator 1 and serves to encapsulate and protect the upper electrode 14 and the piezoelectric material 13, greatly improving the safety and stability of the liquid ejection head.

[0052] Among them, the encapsulation sheet 5 can be a silicon-based protective substrate. The bottom surface of the encapsulation sheet 5 has a recessed empty groove inward, and the upper electrode 14 and the piezoelectric material 13 can be avoided from being contacted through the empty groove. The encapsulation sheet 5 can be bonded to the lower electrode 12 and / or the metal wire 15 by 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 formed structure, and the open area is reserved in the form of a through hole in this example.

[0053] In this embodiment, the piezoelectric material 13 is a single-crystal piezoelectric thin film material. The piezoelectric material 13 of this invention patent is made by processing a single-crystal piezoelectric thin film material. Since the processing of the single-crystal piezoelectric thin film material can use wet etching technology, the over-etching problem of dry etching is effectively avoided, the preparation accuracy is guaranteed, the performance of the liquid ejection head is improved, and the preparation cost of the liquid ejection head is reduced. 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 0.5μm and 2μm.

[0054] The vibration membrane 11 is composed of silicon and silicon dioxide in sequence. 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, 0 < z1 + z2 ≤ 1.5μm, 0 < z1 ≤ 1.5μm, and 0 ≤ z2 ≤ 1.5μm are satisfied.

[0055] 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 an 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 realize the 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.

[0056] The actuator 1 further includes a dielectric layer 16 disposed between the metal wire 15 and the lower electrode 12. The dielectric layer 16 has an isolation function, and isolates between the metal wire 15 and the lower electrode 12 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, and 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 can include at least one of silicon, aluminum, zirconium, titanium, and lead.

[0057] The actuator 1 further includes a buffer layer 17 located between the lower electrode 12 and the diaphragm 11 and 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, and 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.

[0058] The actuator 1 further includes an oxide electrode layer 18 located between the piezoelectric material 13 and the lower electrode 12 and connected to the piezoelectric material 13 and the lower electrode 12. By disposing 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, further improving the safety and stability. Among them, the oxide electrode layer 18 can also be located between the upper electrode 14 and the piezoelectric material 13 and connected to the upper electrode 14 and the piezoelectric material 13. The material of the oxide electrode layer 18 can be strontium ruthenate.

[0059] 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 and battery manufacturing equipment.

[0060] Although the specific embodiments 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 principle and essence of the present invention, those skilled in the art can make various changes or modifications to these embodiments, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A liquid ejection head, characterized in that, It includes an actuator, a flow channel sheet and a nozzle sheet. The actuator includes an upper electrode, a lower electrode, a piezoelectric material and a vibration film. The vibration film is connected to the top end of the flow channel sheet, and a pressure chamber is formed between the vibration film and the flow channel sheet. The nozzle sheet has a nozzle orifice, the nozzle sheet is connected to the bottom end of the flow channel sheet, and the nozzle orifice is communicated with the pressure chamber. The top surface and the 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, and the lower electrode is connected to the top surface of the vibration film facing away from the pressure chamber. The upper electrode is a signal electrode and 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 side by side along the length direction of the liquid ejection head; and / or, the nozzle sheet has multiple nozzle orifices, and each pressure chamber is communicated with at least one nozzle orifice; and / or, the number of the upper electrodes and the piezoelectric materials is multiple, and the multiple upper electrodes are respectively arranged corresponding to the multiple pressure chambers, and the bottom surface of the lower electrode entirely covers the vibration film and the multiple pressure chambers.

3. The liquid ejection head according to claim 1, 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 greater than the top surface area of the piezoelectric material, and the outer edge of the upper electrode is not exposed from the side surface of the piezoelectric material.

4. The liquid ejection head according to claim 1, wherein The actuator further includes multiple metal wires. One end of each metal wire is electrically connected to the upper electrode, the other end of the metal wire is connected to an external control area, and the multiple 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 arranged between the metal wire and the lower electrode; preferably, the material of the dielectric layer is Al2O3, SiO2, resin or lead zirconate titanate.

6. The liquid ejection head according to claim 1, wherein The actuator 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; preferably, the material of the buffer layer is zirconia.

7. The liquid ejection head according to claim 1, wherein The actuator 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; preferably, the material of the oxide electrode layer is strontium ruthenate.

8. The liquid ejection head according to claim 1, characterized in that, The liquid ejection head further includes a packaging sheet, and the packaging sheet is connected to the top end of the actuator facing away from the flow channel sheet, and both the upper electrode and the piezoelectric material are located within the packaging sheet.

9. The liquid ejection head according to claim 1, wherein 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 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.

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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