Spraying hole structure, spraying hole chip comprising spraying hole structure and ink-jet printing head

Abstract

The invention discloses a spray orifice structure, a spray orifice chip comprising the spray orifice structure and an ink-jet printing head. The spraying hole structure comprises a spraying hole which is a first cylindrical empty groove, and the diameter w1 of the spraying hole is larger than or equal to 10 micrometers and smaller than or equal to 50 micrometers; the glue sliding hole is a second cylindrical empty groove, and the diameter w2 of the glue sliding hole is larger than or equal to 20 micrometers and smaller than or equal to 80 micrometers, and w2 is larger than w1; the glue sliding hole and the spraying hole are concentrically arranged; the connecting surface is connected with the spraying hole and the glue sliding hole; the thickness h2 of the connecting face and the thickness h3 of the glue sliding hole meet the condition that the sum of h2 and h3 is larger than or equal to 40 micrometers and smaller than or equal to 150 micrometers. Through smooth flow channel transition of the connecting surface, turbulent flow is effectively restrained, flow resistance is reduced, and therefore the stability of liquid drop forming and the spraying precision are improved; meanwhile, by optimizing the structural size, compact layout is achieved in the horizontal direction, a high-density spray hole array is supported, it is ensured that the overall structure has enough mechanical strength and anti-blocking reliability, and the high-precision ink-jet printing nozzle is suitable for the fields of high-precision ink-jet printing and the like.

Description

Technical Field

[0001] This invention relates to a nozzle structure, a nozzle chip including the nozzle structure, and an inkjet printhead. Background Technology

[0002] In inkjet printing technology, the nozzle is the core structure of the printhead that enables precise ink droplet ejection. Under pressure, liquid moves directionally through this microstructure and forms droplets. As the requirements for printing resolution continue to increase in fields such as high-precision printing and electronic manufacturing, nozzle size is shrinking and the density of nozzles is increasing. This poses an extreme challenge to the processing accuracy and consistency of nozzles, and traditional processes such as laser and stamping are gradually becoming insufficient to meet the requirements.

[0003] Currently, dry etching technology has become the main method for fabricating such high-precision microporous structures. However, during the encapsulation process, the adhesive used for bonding is prone to intruding into the nozzle under pressure, causing blockage. To address this, the industry typically sets a shallow groove structure with a larger diameter concentrically outside the nozzle inlet, called a "glue channel," to accommodate and block the adhesive.

[0004] However, while this structure offers advantages in preventing clogging, it also introduces new challenges: On the one hand, the interface between the glue channel and the nozzle is usually quite steep, easily generating turbulence and pressure disturbances when the liquid flows through, which is not conducive to the formation of stable, oriented droplets. On the other hand, to achieve a high-density (e.g., above 300 npi per row) nozzle array layout, the space occupied by each nozzle structure on the horizontal plane must be strictly controlled. At this point, the design of the diameter and depth of the glue channel itself falls into a dilemma: if a larger diameter or deeper etching is used to ensure sufficient glue-containing space and structural strength, it will encroach on the position of adjacent nozzles, limiting the density increase; conversely, if the diameter and depth are excessively compressed in pursuit of high density, it may weaken its anti-clogging function or lead to local structural weakness in the chip, affecting overall reliability. Existing structures struggle to synergistically optimize anti-clogging capability, flow performance, and structural strength within a small space.

[0005] Therefore, there is an urgent need for a new type of nozzle structure that can effectively balance the requirements of anti-clogging, low flow resistance and high reliability within a compact layout space, ensuring stable and accurate inkjet performance in highly integrated printheads. Summary of the Invention

[0006] The technical problem this invention aims to solve is to overcome the shortcomings of existing nozzle structures in achieving both anti-clogging, low flow resistance, and high reliability in high-density layouts. This invention provides a nozzle structure, a nozzle chip incorporating this structure, and an inkjet printhead. By smoothing the flow channel transition at the interface, this invention effectively suppresses turbulence and reduces flow resistance, thereby improving droplet formation stability and jetting accuracy. Simultaneously, by optimizing structural dimensions, a compact layout is achieved in the horizontal direction, supporting high-density nozzle arrays, and ensuring sufficient mechanical strength and anti-clogging reliability of the overall structure, making it suitable for high-precision inkjet printing and other fields.

[0007] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0008] This invention provides a nozzle structure, comprising:

[0009] The nozzle is a first cylindrical slot with a diameter w1 that satisfies 10μm≤w1≤50μm;

[0010] A glue-feeding orifice, wherein the glue-feeding orifice is a second cylindrical slot, and its diameter w2 satisfies 20μm≤w2≤80μm and w2>w1; the glue-feeding orifice is concentrically arranged with the spray orifice; and

[0011] A connecting surface connects the spray hole and the glue-feeding hole; the thickness h2 of the connecting surface and the thickness h3 of the glue-feeding hole satisfy 40μm≤h2+h3≤150μm.

[0012] In this invention, the diameter w1 of the nozzle can satisfy 20μm≤w1≤26μm, preferably 23μm≤w1≤25μm, for example 20μm, 23μm or 24μm. The nozzle diameter w1 is mainly determined by the design of the fluid system, and its value directly affects the flow resistance characteristics of the nozzle.

[0013] In this invention, the diameter w2 of the glue-feeding orifice can satisfy w2≥1.5×w1, for example, 30μm, 40μm, or 45μm. This dimensional relationship ensures that the flow resistance of the glue-feeding orifice is significantly lower than that of the nozzle. With the same thickness, the flow resistance of the glue-feeding orifice can be reduced to less than 20% of the nozzle flow resistance, thus not becoming the dominant flow resistance component in the overall flow channel. Simultaneously, the size of w2 is also constrained by the nozzle arrangement density, requiring a balance between flow resistance optimization and high-density layout.

[0014] In this invention, the connecting surface can be a curved surface, a conical surface, or a plane with a chamfer.

[0015] In this invention, the thickness h1 of the nozzle can satisfy 0 < h1 ≤ 100 μm, preferably 40 μm ≤ h1 ≤ 55 μm, for example 45 μm or 50 μm. h1 is mainly determined by the fluid system design.

[0016] In this invention, the thickness h2 of the connecting surface can satisfy 0 < h2 < 25 μm, for example 5 μm, 10 μm or 15 μm.

[0017] In this invention, the thickness h3 of the glue-feeding hole can satisfy 25μm < h3 < 150μm, for example 25μm, 30μm or 35μm.

[0018] In this invention, preferably, the thickness h2 of the connecting surface and the thickness h3 of the glue-feeding hole satisfy 40μm≤h2+h3≤60μm, more preferably 45μm≤h2+h3≤55μm, for example 40μm or 50μm.

[0019] In this invention, the total thickness of the nozzle thickness h1, the connecting surface thickness h2, and the glue-feeding orifice thickness h3 can satisfy 80μm≤h1+h2+h3≤100μm, for example, 80μm, 85μm, or 100μm. The setting of the total thickness must balance structural strength and flow resistance control: a larger thickness results in higher mechanical strength, but also leads to a significant increase in flow resistance. The above range represents an optimization result between structural reliability and fluid performance.

[0020] In this invention, the angle α1 between the side surface of the nozzle and the bottom surface of the nozzle structure can satisfy α1 ≥ 90°, for example, 90°. This angle setting helps to converge and guide the ink within the nozzle, thereby improving the stability of droplet formation and ejection.

[0021] In this invention, the angle α2 between the side surface of the connecting surface and the bottom surface of the nozzle structure can satisfy 150°≤a2≤175°, preferably 165°≤a2≤175°, for example 165°, 170°, or 175°. By controlling the angle α2, a gradual transition is formed between the glue-feeding orifice and the nozzle, which can significantly suppress turbulence and reduce flow resistance. If α2 is 180°, the glue-feeding orifice and the nozzle are directly connected, and the flow channel cross-section contracts abruptly, which can easily induce turbulence and increase flow resistance, affecting droplet stability. Generally speaking, the smaller α2 is, the smoother the flow channel transition and the more ideal the turbulence suppression effect. However, if α2 is too small, the thickness h2 of the connecting surface will increase significantly, thereby introducing unnecessary flow resistance. The flow resistance at the connecting surface includes flow channel friction loss and cross-section contraction loss, and increasing h2 will directly increase friction loss. Therefore, the preferred range of α2 is a balance achieved between suppressing turbulence and controlling flow resistance through process adjustment.

[0022] In this invention, the angle α3 between the side surface of the glue-feeding orifice and the bottom surface of the nozzle structure can satisfy α3 ≥ 90°, for example, 90°. The use of a vertical or near-vertical sidewall design facilitates precise control of the orifice diameter during manufacturing, avoiding orifice diameter enlargement caused by lateral etching. This allows for sufficient clearance between adjacent glue-feeding orifices in high-density nozzle arrays (e.g., single-row 300npi or higher), preventing mutual interference and thus supporting higher integration density.

[0023] In this invention, the material of the nozzle structure can be selected from silicon, and its surface is provided with a SiO2 passivation film.

[0024] In this invention, preferably, a hydrophobic film is provided on the lower surface of the nozzle, and the material of the hydrophobic film is selected from fluorine-containing nickel alloy and / or polysiloxane.

[0025] The present invention also provides a nozzle chip, including the nozzle structure as described above.

[0026] In this invention, preferably, multiple nozzle structures are arranged in at least one column, with each column having a nozzle density of 250-400 npi, for example, 300 npi, where npi represents the number of nozzles per inch on the printhead. The nozzle structure of this invention can be applied to high-density (≥250 npi) nozzle chips, meeting the high requirements of fields such as high-precision printing and electronic manufacturing.

[0027] In this invention, preferably, the nozzle chip includes two rows of nozzle structures, which are arranged in parallel or staggered arrangement.

[0028] The present invention also provides an inkjet printhead, which includes the nozzle structure as described above, or the nozzle chip as described above.

[0029] 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.

[0030] The reagents and raw materials used in this invention are all commercially available.

[0031] The positive and progressive effects of this invention are as follows:

[0032] This invention effectively smooths the transition interface of the fluid channel by setting a connecting surface between the nozzle and the glue outlet, significantly suppressing the generation of turbulence and reducing local flow resistance, thereby helping to form more stable and more directional droplets and improving the accuracy and consistency of inkjet printing.

[0033] Meanwhile, by coordinating and optimizing key dimensions such as nozzle diameter, glue-feeding hole diameter, and the total thickness of the connecting surface and glue-feeding hole, the structure of this invention achieves a compact layout in the horizontal direction, breaking through the limitations of traditional designs on nozzle arrangement density. This allows a single-row nozzle density to reach 250-400 npi or even higher, providing crucial support for ultra-high precision printing. Furthermore, while achieving high density and anti-clogging functionality, this structure ensures that the nozzle chip has sufficient overall thickness and mechanical strength, effectively avoiding the risk of brittleness due to structural weakness, thereby significantly improving the device's durability and long-term reliability.

[0034] In summary, the nozzle structure and the nozzle chip and inkjet printhead included therein provided by this invention can simultaneously meet the performance requirements of high density, high stability and high reliability, and are especially suitable for advanced fields with stringent requirements for printing quality, such as high-precision printing and electronic manufacturing. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the nozzle structure in Example 1.

[0036] Figure 2 This is a schematic diagram of the nozzle structure in Example 3.

[0037] Figure 3 This is a schematic diagram of the nozzle chip in Example 4.

[0038] Explanation of reference numerals in the attached figures:

[0039] Nozzle 1

[0040] Connection surface 2

[0041] Glue-filled hole 3 Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0043] Example 1

[0044] Figure 1 This is a schematic diagram of the nozzle structure in this embodiment. As shown in the figure, this embodiment provides a nozzle structure suitable for high-density inkjet printheads, and its specific structure and key dimensions are as follows:

[0045] The nozzle is a first cylindrical cavity with a diameter w1 of 24 μm and a thickness h1 of 50 μm. The angle a1 between the sidewall of the nozzle and the bottom surface is 90°. This angle helps the ink to converge within the nozzle, improving the directionality of droplet ejection.

[0046] The glue-feeding orifice is a second cylindrical groove, concentrically positioned with the nozzle, and has a diameter w2 of 45 μm, greater than w1. This design ensures that, at the same thickness, the flow resistance of the glue-feeding orifice is significantly lower than that of the nozzle, preventing it from becoming a major resistance component in the fluid system. The thickness h3 of the glue-feeding orifice is 35 μm, and the angle a3 between its sidewall and bottom surface is 90°. This vertical design allows for better dimensional control during photolithography and etching processes, ensuring precise orifice diameter and guaranteeing the necessary gaps between adjacent nozzles in a high-density array.

[0047] The connecting surface is conical and used to connect the nozzle and the glue channel. The thickness h2 of the connecting surface is 15μm, and the angle a2 between its sidewall and bottom surface is 170°. This angle forms a smooth transition channel between the glue channel and the nozzle, which can effectively suppress turbulence caused by abrupt changes in the channel cross-section and significantly reduce local flow resistance. The sum of h2 and h3 is 50μm, and the total thickness of the nozzle, connecting surface, and glue channel (h1+h2+h3) is 100μm. This total thickness ensures sufficient mechanical strength for the overall chip structure and prevents chip cracking, while also avoiding excessively high overall flow resistance due to excessive thickness.

[0048] The nozzle structure is fabricated using single-crystal silicon as the substrate, and a SiO2 passivation film is formed on its surface through thermal oxidation. A hydrophobic film containing fluorine-nickel alloy is also deposited on the lower surface of the nozzle by vapor deposition to improve ink wettability and promote droplet separation.

[0049] Example 2

[0050] This embodiment has a structure that is basically the same as that of Embodiment 1. The difference is that the shape and some dimensions of the connection surface are optimized to further balance the flow resistance and turbulence suppression effect.

[0051] In this embodiment, the nozzle diameter w1 is 23 μm, the thickness h1 is 45 μm, and the angle a1 between the nozzle sidewall and the bottom surface is 90°. The glue-feeding orifice diameter w2 is 40 μm, the thickness h3 is 30 μm, and the sidewall remains vertical (a3 is 90°). The connecting surface uses a curved transition, with a thickness h2 of 10 μm, making the sum of h2 + h3 40 μm. The angle a2 between the connecting surface sidewall and the bottom surface is 165°. This smaller angle makes the flow channel transition smoother and the turbulence suppression effect better. At the same time, because h2 is controlled to be small, the additional flow resistance caused by friction of the connecting surface is also kept at a low level. The total thickness of the three parts h1 + h2 + h3 is 85 μm, which further reduces the overall flow resistance while maintaining reliability.

[0052] Example 3

[0053] Figure 3 This is a schematic diagram of the nozzle structure in this embodiment.

[0054] In this embodiment, the nozzle diameter w1 is 20 μm, the thickness h1 is 50 μm, and the angle a1 between the nozzle sidewall and the bottom surface is 90°. The glue-feeding orifice diameter w2 is 30 μm, the thickness h3 is 25 μm, and the sidewall remains vertical (a3 is 90°). The connecting surface is a chamfered plane with a thickness h2 of 15 μm and an angle a2 of 175°. The total thickness h1+h2+h3 of the nozzle, connecting surface, and glue-feeding orifice is 90 μm. Although the total thickness is reduced, due to the optimized design of the thickness ratio of h1, h2, and h3 and the angle of the connecting surface, this structure can achieve an ultra-high density layout while maintaining the necessary structural rigidity and ensuring a smooth transition from the glue-feeding orifice to the nozzle.

[0055] Example 4

[0056] This embodiment provides a nozzle chip, which includes multiple nozzle structures as described in any of embodiments 1-3, and is integrated on the same substrate in a specific array manner. Figure 3 This is a schematic diagram of the nozzle chip in this embodiment.

[0057] The nozzle chip includes a substrate (e.g., a silicon substrate) and an array of nozzle structures formed thereon by microfabrication processes (e.g., photolithography, dry etching). The nozzle structures preferably employ the parameter ranges described in any of Examples 1-3. These nozzle structures are arranged in at least one straight column on the chip. The center-to-center distance of the nozzles in each column is consistent, and their arrangement density is determined by key dimensions such as the nozzles and the adhesive channels, and can be achieved in the range of 250 npi to 400 npi (npi, or holes per inch).

[0058] Specifically, a single-row nozzle structure can be set on a single nozzle chip. To achieve higher printing resolution (dpi, dots per inch), a multi-row nozzle structure can also be integrated. When multiple rows exist, they can be arranged in parallel. Preferably, a staggered arrangement of multiple rows is used. For example, two rows of nozzles are arranged parallel, but the positions of the nozzles in the two rows are staggered by half a spacing in the direction perpendicular to the column. This design, without significantly increasing the manufacturing difficulty of a single row, can double the actual print dot density (dpi) based on the nozzle arrangement density (npi) through complementary jetting from the two rows of nozzles, thereby greatly improving print quality.

[0059] In a preferred embodiment of the present invention, the nozzle chip may employ a design comprising two rows of nozzles, each row having a nozzle density of 300 npi, and the two rows of nozzles arranged in the aforementioned staggered manner. This configuration fully utilizes the advantages of the nozzle structure of the present invention in terms of vertical sidewalls and compact size, ensuring no risk of mutual interference between adjacent nozzles (especially between glue-feeding nozzles) at high densities, while effectively improving the final printing resolution through staggered arrangement.

[0060] Comparative Example 1

[0061] A traditional nozzle structure has no connecting surface transition between the glue-feeding hole and the nozzle.

[0062] In this comparative example, the nozzle diameter w1 is 20 μm, the thickness h1 is 40 μm, and the angle a1 between the nozzle sidewall and the bottom surface is 90°. The glue-feeding orifice is conical, with a maximum diameter w2 of 90 μm and a thickness h3 of 25 μm.

[0063] Comparative Example 2

[0064] A traditional nozzle structure has no connecting surface transition between the glue-feeding hole and the nozzle.

[0065] In this comparative example, the nozzle diameter w1 is 20 μm, the thickness h1 is 40 μm, and the angle a1 between the nozzle sidewall and the bottom surface is 90°. The glue-feeding orifice diameter w2 is 90 μm, the thickness h3 is 25 μm, and the sidewall remains vertical (a3 is 90°).

[0066] Effect Example

[0067] The nozzle structures of the above embodiments and comparative examples were subjected to inkjet printing tests, and the test results are as follows:

[0068] (1) Space optimization of high-density layout

[0069] Comparative Example 1 requires a larger glue-feeding orifice diameter w2, which occupies more space in the horizontal direction, limiting the further reduction of the orifice center distance and making it difficult to support ultra-high density (such as single-row 300npi or more) array layouts.

[0070] Embodiments 1-4 of the present invention can ensure that the flow resistance of the glue-feeding orifice is much lower than that of the spray orifice, while leaving more ample and controllable gaps between adjacent spray orifices in the high-density array, fundamentally supporting the reduction of the center distance of the spray orifices, and providing a structural basis for achieving a single-row arrangement density of 250-400 npi or even higher.

[0071] (2) Improved fluid performance at high density

[0072] Under the same operating conditions, the conventional structure in Comparative Example 2, lacking a smooth transition between the glue-feeding orifice and the spray orifice, is prone to turbulence and pressure disturbances at the abrupt change in the inlet cross-section, resulting in poor droplet formation stability and jet linearity. In contrast, the embodiments of the present invention achieve a smooth transition of the flow channel through the connecting surface (conical surface, curved surface, or plane with chamfer), effectively suppressing turbulence and reducing local flow resistance, thereby contributing to the formation of more stable and more directional droplets.

[0073] In summary, the nozzle structure provided in Embodiments 1-4 of this invention, by introducing a connecting surface and coordinating the optimization of key dimensions such as nozzle diameter, glue discharge hole diameter, and the total thickness of the connecting surface and glue discharge hole, has successfully achieved an excellent balance among multiple mutually restrictive technical objectives such as suppressing turbulence, reducing flow resistance, achieving high-density layout, and ensuring structural strength. Its overall performance is significantly better than that of traditional structures.

[0074] 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 nozzle structure, characterized in that, It includes: The nozzle is a first cylindrical slot with a diameter w1 that satisfies 10μm≤w1≤50μm; The glue-feeding hole is a second cylindrical slot with a diameter w2 that satisfies 20μm≤w2≤80μm and w2>w1; the glue-feeding hole is concentrically arranged with the spray hole. A connecting surface connects the spray hole and the glue-feeding hole; the thickness h2 of the connecting surface and the thickness h3 of the glue-feeding hole satisfy 40μm≤h2+h3≤150μm.

2. The nozzle structure as described in claim 1, characterized in that, The nozzle structure satisfies one or more of the following conditions: a. The diameter w1 of the nozzle satisfies 20μm≤w1≤26μm; b. The diameter w2 of the glue-feeding hole satisfies w2≥1.5×w1; c. The connecting surface is a curved surface, a conical surface, or a plane with a chamfer.

3. The nozzle structure as described in claim 1, characterized in that, The nozzle structure satisfies one or more of the following conditions: a. The thickness h1 of the nozzle satisfies 0 < h1 ≤ 100 μm; b. The thickness h2 of the connecting surface satisfies 0 < h2 < 25 μm; c. The thickness h3 of the glue-feeding hole satisfies 25μm<h3≤150μm; d. The thickness h2 of the connecting surface and the thickness h3 of the glue-feeding hole satisfy 40μm≤h2+h3≤60μm; e. The total thickness of the spray hole thickness h1, the connecting surface thickness h2, and the glue-feeding hole thickness h3 satisfies 80μm≤h1+h2+h3≤100μm.

4. The nozzle structure as described in claim 1, characterized in that, The nozzle structure satisfies one or more of the following conditions: a. The diameter w1 of the nozzle satisfies 23μm≤w1≤25μm; b. The thickness h1 of the nozzle satisfies 40μm≤h1≤55μm; c. The thickness h2 of the connecting surface and the thickness h3 of the glue-feeding hole satisfy 45μm≤h2+h3≤55μm.

5. The nozzle structure as described in claim 1, characterized in that, The nozzle structure satisfies one or more of the following conditions: a. The angle a1 between the side surface of the nozzle and the bottom surface of the nozzle structure satisfies a1≥90°; b. The angle a2 between the side surface of the connecting surface and the bottom surface of the nozzle structure satisfies 150°≤a2≤175°; c. The angle a3 between the side of the glue-feeding hole and the bottom surface of the spray hole structure satisfies a3≥90°.

6. The nozzle structure as described in claim 5, characterized in that, The nozzle structure satisfies one or more of the following conditions: a. The angle a2 between the side surface of the connecting surface and the bottom surface of the nozzle structure satisfies 165°≤a2≤175°; b. The angle a3 between the side of the glue-feeding hole and the bottom surface of the spray hole structure is 90°.

7. The nozzle structure as described in claim 1, characterized in that, The nozzle structure satisfies one or more of the following conditions: a. The material of the nozzle structure is selected from silicon, and its surface is provided with a SiO2 passivation film; b. A hydrophobic film is provided on the lower surface of the nozzle, and the material of the hydrophobic film is selected from fluorine-containing nickel alloy and / or polysiloxane.

8. A nozzle chip, characterized in that, Includes the nozzle structure as described in any one of claims 1-7.

9. The nozzle chip according to claim 8, characterized in that, Multiple of the aforementioned nozzle structures are arranged in at least one column, with each column having a nozzle density of 250-400 npi, where npi represents the number of nozzles per inch on the nozzle head.

10. An inkjet printhead, characterized in that, It includes the nozzle structure as described in any one of claims 1-7, or the nozzle chip as described in claim 8 or 9.

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