A vibration structure, a vibrator including the vibration structure, and an inkjet device

Abstract

The application provides a vibrating structure, a vibrator comprising the vibrating structure and an inkjet device. The vibrating structure comprises a vibrating diaphragm and a reinforcing structure arranged on the vibrating diaphragm, the reinforcing structure comprising an electrode layer, a piezoelectric layer and a dielectric layer which are sequentially stacked; the reinforcing structure is arranged on an edge support area of the vibrating diaphragm, the edge support area corresponding to an end of a vibrating cavity; a coverage area of the lower electrode layer extends from one end of the vibrating cavity along a preset direction towards the top. Through the multilayer stacked structure of "lower electrode layer-piezoelectric layer-dielectric layer", the application realizes the synergistic reinforcing effect among materials. The lower electrode layer with ductility can effectively absorb and disperse vibration energy, thereby inhibiting the generation of cracks; and the hard piezoelectric layer and the dielectric layer superimposed thereon can enhance the rigidity and bending strength of the structure as a whole. This synergistic mechanism effectively inhibits the fragmentation of the vibrating diaphragm and the failure of the vibrating structure, and improves the reliability and service life of the vibrating device.

Description

Technical Field

[0001] The present invention relates to a vibration structure, a vibrator including the vibration structure, and an inkjet device. Background Technology

[0002] In piezoelectric inkjet technology, to further improve image quality, nozzle fabrication techniques are increasingly focused on higher precision and density. With the increasing nozzle density, traditional piezoelectric inkjet head fabrication techniques can no longer meet the precision requirements, while thin-film piezoelectric printheads fabricated using microelectromechanical systems (MEMS) technology have become the mainstream in this field.

[0003] These MEMS printheads typically use silicon and its oxides as the diaphragm material, whose high hardness provides sufficient stress to drive the ink. However, under high-frequency, long-term cyclic vibration conditions, the diaphragm, especially its edge support area (i.e., the corners of the vibration cavity), is prone to vibration fatigue due to alternating stress, leading to cracking and irreversible structural failure, which limits the lifespan of the device.

[0004] Existing enhancement techniques do not specifically address these long-term vibration fatigue reliability issues; for example, they only target cracks caused by thermal stress during manufacturing. Therefore, there is an urgent need in the field for a solution that can effectively improve the fatigue resistance of the vibrating diaphragm to address the key challenges faced by high-density MEMS nozzles in terms of long-term vibration reliability. Summary of the Invention

[0005] The technical problem this invention aims to solve is to overcome the shortcomings of existing MEMS diaphragms, such as edge cracking and short service life due to long-term vibration fatigue. This invention provides a vibration structure, a vibrator incorporating this structure, and an inkjet device. Through a multi-layered stacked structure of a lower electrode layer, a piezoelectric layer, and a dielectric layer, this invention achieves synergistic reinforcement between materials. The ductile lower electrode layer effectively absorbs and disperses vibration energy, thereby suppressing crack formation; while the hard piezoelectric and dielectric layers superimposed on it enhance the overall stiffness and bending strength of the structure. This synergistic mechanism effectively suppresses diaphragm breakage and vibration structure failure, improving the reliability and service life of the vibration device.

[0006] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0007] The present invention provides a vibration structure, which includes a vibration diaphragm and a reinforcing structure disposed on the vibration diaphragm. The reinforcing structure includes a lower electrode layer, a piezoelectric layer and a dielectric layer stacked sequentially. The reinforcing structure is disposed in the edge support region of the vibration diaphragm, and the edge support region corresponds to the end of the vibration cavity.

[0008] The coverage area of ​​the lower electrode layer extends from one end of the self-vibrating cavity towards the top along a predetermined direction; the relationship between the width w1 of the lower electrode layer and the width w2 of the piezoelectric layer satisfies w2≥w1; the relationship between the width w2 of the piezoelectric layer and the width w3 of the dielectric layer satisfies w2≥w3.

[0009] In this invention, the material of the vibrating diaphragm may include one or more of SiO2, Si, and ZrO2.

[0010] In this invention, preferably, a buffer layer is further included between the vibrating diaphragm and the lower electrode layer.

[0011] The material of the buffer layer can be selected from ZrO2;

[0012] The thickness t0 of the buffer layer can satisfy 0 < t0 ≤ 300 nm.

[0013] In this invention, the material of the lower electrode layer is selected from metal electrodes and / or oxide electrodes; the metal of the metal electrode is selected from one or more of Au, Ag, Pt, and Ir; the oxide electrode is selected from strontium ruthenium oxide (SRO). Preferably, the material of the electrode layer is selected from Pt and / or strontium ruthenium oxide.

[0014] In this invention, the thickness t1 of the lower electrode layer can satisfy 0 < t1 ≤ 500 nm.

[0015] In this invention, the relationship between the width w1 of the lower electrode layer and the width w2 of the piezoelectric layer is preferably 0≤w1-w2≤10μm, and more preferably 0≤w1-w2≤5μm.

[0016] In this invention, the material of the piezoelectric layer can be selected from lead zirconate titanate (PZT).

[0017] In this invention, the thickness t2 of the piezoelectric layer can satisfy 0 < t2 ≤ 3000 nm.

[0018] In this invention, the dielectric layer can be made of metal oxides and / or resins, wherein the metal oxides are selected from one or more oxides of Si, Zr, Ti, and Al. Preferably, the metal oxides are one or more of SiO2, ZrO2, TiO2, and Al2O3.

[0019] In this invention, the thickness t3 of the dielectric layer can satisfy 0 < t3 ≤ 5000 nm.

[0020] In this invention, preferably, the side of the dielectric layer away from the piezoelectric layer further includes an upper electrode layer.

[0021] The material of the upper electrode layer can be selected from one or more of Cr, Ti, Au, Ag, Pt and Ir, such as Au.

[0022] The thickness t4 of the upper electrode layer satisfies 0 < t4 ≤ 1000 nm.

[0023] When the reinforcing structure further includes an upper electrode layer, the relationship between the width w3 of the dielectric layer and the width w4 of the upper electrode layer can satisfy w3≥w4.

[0024] When the reinforcing structure further includes an upper electrode layer, preferably, a groove is provided between the dielectric layer and the piezoelectric layer to accommodate the upper electrode layer, so that the upper electrode layer and the lower electrode layer are electrically connected. This structural design can effectively avoid parasitic capacitance between the upper and lower electrodes.

[0025] In some preferred embodiments, the reinforcing structure includes a buffer layer, a lower electrode layer, a piezoelectric layer, a dielectric layer, and an upper electrode layer stacked sequentially; wherein,

[0026] The buffer layer is made of ZrO2, and the thickness t0 of the ZrO2 satisfies 0 < t0 ≤ 300 nm;

[0027] The material of the lower electrode layer is selected from Pt and strontium ruthenium oxide. The thickness t11 of the Pt satisfies 0 < t11 ≤ 300 nm, and the thickness t12 of the strontium ruthenium oxide satisfies 0 < t12 ≤ 200 nm.

[0028] The piezoelectric layer is made of lead zirconate titanate, and the thickness t2 of the lead zirconate titanate satisfies 0 < t2 ≤ 3000 nm;

[0029] The dielectric layer is made of SiO2, and the thickness t3 of the SiO2 satisfies 0 < t3 ≤ 5000 nm;

[0030] The material of the upper electrode layer is selected from Au, and the thickness t4 of the Au satisfies 0 < t4 ≤ 1000 nm.

[0031] The present invention also provides a vibrator comprising the vibrating structure as described above.

[0032] The present invention also provides an inkjet device comprising the vibrating structure or the vibrator as described above.

[0033] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0034] The reagents and raw materials used in this invention are all commercially available.

[0035] The positive and progressive effects of this invention are as follows:

[0036] This invention achieves synergistic reinforcement between materials through a multi-layered stacked structure of "lower electrode layer - piezoelectric layer - dielectric layer". The ductile lower electrode layer can effectively absorb and disperse vibration energy, thereby suppressing crack formation; while the hard piezoelectric layer and dielectric layer superimposed on it enhance the overall stiffness and bending strength of the structure. This synergistic mechanism effectively suppresses the breakage of the vibrating diaphragm and the failure of the vibrating structure, improving the reliability and service life of the vibrator.

[0037] Based on this, the combined structure of "lower electrode layer - piezoelectric layer - dielectric layer - upper electrode layer" can absorb and disperse energy more efficiently, especially the impact energy caused by external impact, further suppressing crack propagation, thereby further improving the reliability and service life of the vibrator. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the vibrator in Example 1.

[0039] Figure 2 This is a schematic diagram of the vibrator in Example 2.

[0040] Explanation of reference numerals in the attached figures:

[0041] Vibrating cavity 1

[0042] Vibrating diaphragm 2

[0043] First vibrating diaphragm 21

[0044] Second diaphragm 22

[0045] Buffer layer 3

[0046] Lower electrode layer 4

[0047] First lower electrode layer 41

[0048] Second lower electrode layer 42

[0049] Piezoelectric layer 5

[0050] Dielectric layer 6

[0051] Upper electrode layer 7 Detailed Implementation

[0052] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0053] As a reinforcing structure, this invention does not have strict requirements on the graphic design itself, and can be selected according to the actual process used, such as using a rectangle or trapezoid instead of a semicircle.

[0054] Example 1

[0055] Figure 1 This is a schematic diagram of the vibrator in this embodiment. Figure 1 The left figure is a partial top view of the vibrator, with the dashed box representing the outline of the vibration cavity 1. A reinforcing structure is provided at the narrowing point of the vibration cavity 1. The right figure shows a cross-sectional view of the part within the red box. As shown in the figure, this embodiment provides a vibrator, which includes a vibration cavity 1, a vibration diaphragm 2, and a reinforcing structure disposed on the vibration diaphragm. The reinforcing structure is disposed in the edge support area of ​​the vibration diaphragm 2, which corresponds to the end of the vibration cavity and is a vulnerable part where stress concentration occurs during vibration.

[0056] The vibrating diaphragm 2 includes a first vibrating diaphragm 21 and a second vibrating diaphragm 22 stacked together, wherein the first vibrating diaphragm 21 is made of SiO2 and the second vibrating diaphragm 22 is made of Si.

[0057] To improve the fatigue resistance of the edge support area under long-term high-frequency vibration, a reinforcing structure composed of multiple layers of materials is provided on the vibrating diaphragm 2. The reinforcing structure includes a buffer layer 3, a lower electrode layer 4, a piezoelectric layer 5, and a dielectric layer 6 stacked sequentially from bottom to top.

[0058] The lower electrode layer 4 extends from one end of the vibrating cavity 1 towards the top along a predetermined direction, and its coverage area is larger than that of the upper piezoelectric layer 5. For example, the lower electrode layer 4 is wider than the piezoelectric layer 5 by 0 ≤ w1 - w2 ≤ 10 μm in width w1, and further by 0 ≤ w1 - w2 ≤ 5 μm, for example, 2.5 μm. This width difference design allows the lower electrode layer 4 to form a buffer around the edge of the vibrating membrane 2, dispersing vibration stress.

[0059] Meanwhile, the width w2 of the piezoelectric layer 5 is greater than or equal to the width w3 of the dielectric layer 6, so that the piezoelectric layer 5 and the dielectric layer 6 can form a protective cover over the underlying structure.

[0060] In terms of materials and thickness, the buffer layer 3 uses ZrO2 with a thickness t0 of 0 < t0 ≤ 300 nm, for example 150 nm, which plays a role in stress transition and adhesion enhancement.

[0061] The lower electrode layer 4 consists of two layers: the first lower electrode layer 41 is made of Pt with a thickness t11 of 0 < t11 ≤ 300 nm, for example, 150 nm, exhibiting good conductivity and ductility; the second lower electrode layer 42 is made of SRO with a thickness t12 of 0 < t12 ≤ 200 nm, for example, 100 nm, providing good compatibility with the piezoelectric layer. The combined lower electrode layer effectively absorbs vibrational energy and inhibits crack initiation.

[0062] The piezoelectric layer 5 is made of PZT, with a thickness t2 of 0 < t2 ≤ 3000 nm, for example, 1500 nm. The dielectric layer 6 is made of SiO2, with a thickness t3 of 0 < t3 ≤ 5000 nm, for example, 2500 nm. Together, the piezoelectric layer 5 and the dielectric layer 6 provide high structural stiffness, effectively enhancing the overall bending strength to suppress deformation and fatigue during vibration. Simultaneously, both possess excellent insulating properties and can function as insulating materials.

[0063] The vibrator in this embodiment employs a multi-layered collaborative design consisting of a buffer layer, a lower electrode layer, a piezoelectric layer, and a dielectric layer, forming a reinforced structure in the edge support region of the vibrating diaphragm. The lower electrode layer utilizes its ductility to dissipate vibration energy, while the piezoelectric and dielectric layers collectively enhance stiffness and fatigue resistance, thereby significantly alleviating vibration fatigue problems under long-term high-frequency operation, preventing cracking and structural failure, and improving the vibrator's operational reliability and service life.

[0064] Example 2

[0065] like Figure 2 As shown, this embodiment provides another vibrator, which is further optimized based on the structure of embodiment 1. Figure 2 The left image is a partial top view of the vibrator, with the dashed box indicating the outline of the vibration cavity 1. A reinforcing structure is provided at the narrowing point of the vibration cavity 1. The right image shows a cross-sectional view of the area within the red box. The vibrator also includes a vibration cavity 1, a vibrating diaphragm 2, and a reinforcing structure on the vibrating diaphragm. This reinforcing structure is located in the edge support area of ​​the vibrating diaphragm 2, corresponding to the end of the vibration cavity 1, which is the area where vibration stress is most concentrated and is crucial to the long-term reliability of the structure.

[0066] The vibrating diaphragm 2 adopts a layered design, including a first vibrating diaphragm 21 and a second vibrating diaphragm 22. The first vibrating diaphragm 21 is made of SiO2 material, and the second vibrating diaphragm 22 is made of Si material. The combination of the two provides good basic vibration performance and mechanical strength.

[0067] The core of this embodiment lies in the specific composition of the reinforcement structure. From bottom to top, the reinforcement structure comprises a buffer layer 3, a lower electrode layer 4, a piezoelectric layer 5, a dielectric layer 6, and an upper electrode layer 7. This five-layer stacked design of "buffer layer-electrode layer-piezoelectric layer-dielectric layer-upper electrode layer" constitutes a complete, functionally graded mechanical reinforcement unit.

[0068] The dimensions of each functional layer are specially designed to optimize stress distribution:

[0069] The lower electrode layer 4 extends from one end of the self-vibrating cavity 1 toward the top in a predetermined direction. Its width w1 is wider than that of the upper piezoelectric layer 5. For example, the lower electrode layer 4 is wider than the width w2 of the piezoelectric layer 5 by 0≤w1-w2≤10μm, and further by 0≤w1-w2≤5μm, for example, 2.5μm, so as to wrap and protect the edge of the vibrating membrane 2.

[0070] The width w2 of the piezoelectric layer 5 is greater than or equal to the width w3 of the dielectric layer 6 above it, and the width w3 of the dielectric layer 6 is greater than or equal to the width w4 of the uppermost electrode layer 7.

[0071] This bottom-up, progressively narrower width design helps to suppress interlayer stress concentration and the initiation and propagation of edge cracks.

[0072] Regarding the material and thickness parameters, the buffer layer 3 uses ZrO2 with a thickness t0 of 0 < t0 ≤ 300 nm, such as 150 nm, which mainly serves to buffer stress and improve interlayer bonding.

[0073] The lower electrode layer 4 is a composite structure, including a first lower electrode layer 41 (Pt, with a thickness t11 of 0 < t11 ≤ 300 nm, for example 150 nm) and a second lower electrode layer 42 (SRO, with a thickness t12 of 0 < t12 ≤ 200 nm, for example 100 nm), which together provide good conductivity, ductility and lattice matching with the piezoelectric layer.

[0074] The piezoelectric layer 5 is made of PZT, with a thickness t2 of 0 < t2 ≤ 3000 nm, for example, 1500 nm. The dielectric layer 6 is made of SiO2, with a thickness t3 of 0 < t3 ≤ 5000 nm, for example, 2500 nm. Together, the piezoelectric layer 5 and the dielectric layer 6 provide high structural stiffness, effectively enhancing the overall bending strength to suppress deformation and fatigue during vibration. Simultaneously, both possess excellent insulating properties and can function as insulating materials.

[0075] The upper electrode layer 7 is made of one or more of Cr, Ti, Au, Ag, Pt and Ir, with a thickness t4 of 0 < t4 ≤ 1000 nm. The upper electrode is electrically connected to the lower electrode through the through-slots of the dielectric layer and the piezoelectric layer. The upper electrode layer is used to provide the structure with surface ductility and impact resistance.

[0076] This embodiment adds an upper electrode layer 7 to the dielectric layer and uses a specific width to match the lower structure, forming a more complete and synergistic multilayer reinforcement system. This design not only inherits the advantages of the lower electrode layer for energy dissipation and the hard layer for stiffness enhancement in Embodiment 1, but also further optimizes the stress transmission path with the addition of the upper electrode layer and the overall width gradient design, more effectively suppressing the accumulation and release of vibration energy in the edge region. Thus, under more severe high-frequency cyclic loads, it provides the diaphragm (especially the edge support area) with stronger vibration fatigue resistance and a longer service life.

[0077] Effect Example

[0078] To verify the effect of the vibrator reinforcement structure described in this invention on improving vibration fatigue resistance, a vibration comparison test was conducted between the vibrator with a multi-layer reinforcement structure obtained in Example 2 of this invention and a traditional vibrator without a reinforcement structure. Fifty samples of each type were prepared.

[0079] The test was conducted on a high-frequency vibration fatigue testing machine to simulate actual inkjet printing working conditions (the driving frequency and driving voltage, etc., are determined by the product specifications, such as using a 30V driving voltage and a 20kHz driving frequency), and the first visible crack appearing in the support area at the edge of the vibration diaphragm was used as the failure criterion.

[0080] Test results show that the fatigue resistance of vibrators with traditional structures is limited. After approximately 4.5 billion to 5.8 billion vibration cycles, all samples developed cracks at the ends of their vibration cavities (i.e., the edge support area), with an average lifespan of approximately 5.1 billion cycles. Observation revealed that the cracks all originated from this stress concentration area and propagated rapidly, which is completely consistent with the problem of fatigue failure of the diaphragm caused by high alternating stress as pointed out in the background art.

[0081] In contrast, the sample in Example 2, which adopted the reinforcing structure of the present invention, exhibited extremely superior reliability. During continuous testing, all samples showed no cracking in their edge support areas even after 19.5 billion vibration cycles, representing an improvement of approximately four times compared to Comparative Example 1. This result directly and powerfully demonstrates that the multi-layer reinforcing structure proposed in this invention effectively solves the problem of fatigue failure under long-term high-frequency vibration.

[0082] This remarkable effect stems from the synergistic design mechanism of this invention: First, the lower electrode layer, utilizing its excellent ductility, effectively absorbs and disperses the localized high stress from the ends of the vibration cavity, suppressing crack initiation at its source. Second, the upper hard piezoelectric and dielectric layers significantly enhance the overall stiffness and bending strength of the local area, constraining vibration deformation. Finally, the layer-by-layer width gradient design, with the lower layer slightly wider than the upper layer, optimizes the transmission and distribution of interlayer stress, avoiding stress concentration caused by sharp interfaces. This multi-level synergistic effect, from energy dissipation and stiffness enhancement to interface optimization, collectively ensures the long-life operation of the diaphragm under extreme cyclic loading.

[0083] In summary, through comparative testing, this embodiment of the effect demonstrates that the present invention can increase the fatigue life of the vibrator by several times, thereby significantly improving the long-term operational reliability and service life of MEMS inkjet printheads using such vibrators, and effectively meeting the stringent requirements of high-density printing on the reliability of core components.

[0084] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A vibration structure, characterized in that, It includes a vibrating diaphragm and a reinforcing structure disposed on the vibrating diaphragm. The reinforcing structure includes a lower electrode layer, a piezoelectric layer and a dielectric layer stacked in sequence. The reinforcing structure is disposed in the edge support region of the vibrating diaphragm, and the edge support region corresponds to the end of the vibrating cavity. The coverage area of ​​the lower electrode layer extends from one end of the self-vibrating cavity toward the top in a predetermined direction; the relationship between the width w1 of the lower electrode layer and the width w2 of the piezoelectric layer satisfies w1 > w2; the relationship between the width w2 of the piezoelectric layer and the width w3 of the dielectric layer satisfies w2 > w3; The dielectric layer also includes an upper electrode layer on the side away from the piezoelectric layer, and the relationship between the width w3 of the dielectric layer and the width w4 of the upper electrode layer satisfies w3 > w4.

2. The vibration structure as described in claim 1, characterized in that, The material of the lower electrode layer is selected from metal electrodes and / or oxide electrodes; the metal of the metal electrode is selected from one or more of Au, Ag, Pt and Ir; the oxide electrode is selected from strontium ruthenium oxide. And / or, the material of the piezoelectric layer is selected from lead zirconate titanate; And / or, the dielectric layer is made of a metal oxide and / or a resin, wherein the metal oxide is selected from one or more oxides of Si, Zr, Ti and Al; And / or, the material of the vibrating diaphragm includes one or more of SiO2, Si, and ZrO2.

3. The vibration structure as described in claim 1, characterized in that, The thickness t1 of the lower electrode layer satisfies 0 < t1 ≤ 500 nm; And / or, the thickness t2 of the piezoelectric layer satisfies 0 < t2 ≤ 3000 nm; And / or, the thickness t3 of the dielectric layer satisfies 0 < t3 ≤ 5000 nm.

4. The vibration structure as described in claim 1, characterized in that, A buffer layer is also included between the vibrating diaphragm and the lower electrode layer.

5. The vibration structure as described in claim 1, characterized in that, The material of the upper electrode layer is selected from one or more of Cr, Ti, Au, Ag, Pt and Ir; And / or, the thickness t4 of the upper electrode layer satisfies 0 < t4 ≤ 1000 nm.

6. The vibration structure as described in claim 4, characterized in that, The buffer layer is made of ZrO2; And / or, the thickness t0 of the buffer layer satisfies 0 < t0 ≤ 300 nm.

7. The vibration structure as described in claim 1, characterized in that, A groove is provided between the dielectric layer and the piezoelectric layer to accommodate the upper electrode layer, so that the upper electrode layer and the lower electrode layer are interconnected.

8. A vibrator, characterized in that, It includes the vibration structure as described in any one of claims 1-7.

9. An inkjet device, characterized in that, It includes the vibration structure as described in any one of claims 1-7 or the vibrator as described in claim 8.

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