A method and manufacturing system for producing a high-precision microlens array in a liquid environment

Abstract

The present application relates to the technical field of microlens array printing, and provides a method and a manufacturing system for preparing a high-precision microlens array in a liquid environment, which can realize the preparation of the high-precision microlens array through a printing technology of generating droplets by constrained interface vibration in the liquid environment, and can control a piezoelectric ceramic nozzle in the liquid carrier in a liquid carrier container to generate droplets by interface vibration and sequentially print microlenses to form a microlens array through an X, Y and Z three-axis motion platform, the method can manufacture a size-editable microlens array and has extremely high stability. The present application changes the preparation environment of the microlens array, the liquid carrier can effectively protect the droplets during the printing process, and problems such as volatilization and airflow affecting the shape of the microlens during the preparation process can be avoided or alleviated when volatile printing materials are used, so that the microlens array manufacturing process is more stable.

Description

Technical Field

[0001] This invention relates to the field of microlens array printing technology, and in particular to a method and manufacturing system for preparing high-precision microlens arrays in a liquid environment. Background Technology

[0002] Each lens in a microlens array is between 10 and 100 micrometers in size, featuring lightweight, miniaturized, and highly integrated characteristics. Microlens arrays can achieve highly efficient light focusing, beam splitting, and uniform illumination, and have important applications in optical systems, optical communications, imaging and sensing, consumer electronics, and biomedicine.

[0003] Currently, the main methods for manufacturing microlens arrays include photolithography, mold replication, and inkjet printing. Inkjet printing has received considerable attention in recent years due to its high flexibility, uniformity, and material adaptability. However, the mainstream inkjet printing process still takes place in air, making it susceptible to the effects of gravity and surrounding airflow disturbances, which can interfere with the printing accuracy of microlenses. Furthermore, with the increasing application of micro- and nano-optical components in modern optical imaging, optical communication, and display fields, higher requirements are being placed on the manufacturing accuracy of microlens arrays. Conventional inkjet printing technology improves printing accuracy by reducing the nozzle size; however, reduced nozzle size makes them prone to clogging during use, leading to significant manufacturing and maintenance costs. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method and manufacturing system for fabricating high-precision microlens arrays using a printing technique that generates droplets through constrained interfacial vibrations in a liquid environment. This method can produce microlens arrays with editable dimensions and exhibits extremely high stability.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a manufacturing system for a microlens array, comprising a liquid-carrying container fixed to the central region of an X, Y, Z three-axis motion platform by a support frame, a substrate and a stored liquid in the liquid-carrying container, and an editable excitation power supply for adjusting the pressure inside the piezoelectric ceramic nozzle according to the required size for microlens fabrication. The X, Y, Z three-axis motion platform controls the piezoelectric ceramic nozzle to generate droplets in the liquid in the liquid-carrying container through interface vibration, thereby sequentially printing microlenses to form a microlens array.

[0006] The piezoelectric ceramic nozzle includes a piezoelectric actuator mounted on the outer wall of a piezoelectric ceramic glass sleeve. The piezoelectric ceramic glass sleeve is filled with printing liquid. The electrical signal generated by the programmable excitation power supply drives the piezoelectric actuator to produce mechanical deformation, causing the piezoelectric ceramic glass sleeve to be in an expanding or contracting state while generating negative or positive pressure waves within it. Under the cyclic action of negative and positive pressure waves, the neck of the printing liquid breaks during the process of extrusion, re-suction, and re-extrusion. The droplets fall onto the substrate in the liquid carrier under their own gravity, forming microlenses.

[0007] Furthermore, the negative pressure wave or positive pressure wave splits into two and propagates synchronously to both sides along the inner channel of the piezoelectric ceramic glass sleeve.

[0008] At the initial moment, driven by the electrical signal, the piezoelectric actuator generates two negative pressure waves that propagate from the middle of the piezoelectric ceramic glass sleeve to both ends. One of the negative pressure waves reaches the nozzle end of the piezoelectric ceramic glass sleeve, causing the nozzle end to draw back the printing liquid. The other negative pressure wave simultaneously reaches the opening end and is reflected by opposite signs to form a reflected wave.

[0009] One of the two positive pressure waves is linearly superimposed with the reflected wave and moves toward the nozzle end to extrude the printing liquid, while the other positive pressure wave propagates toward the opening end and cancels out the negative pressure wave.

[0010] Furthermore, the X, Y, Z three-axis motion platform includes a UV light source X-direction slider, a piezoelectric ceramic nozzle X-direction slider, a Y-direction slider, a piezoelectric ceramic nozzle Z-direction slider, and a UV light source Z-direction slider. The piezoelectric ceramic nozzle Z-direction slider is equipped with a piezoelectric ceramic nozzle upper clamp and a piezoelectric ceramic nozzle lower clamp to fix the piezoelectric ceramic nozzle. The UV light source Z-direction slider is equipped with a UV light source upper clamp and a UV light source lower clamp to fix the UV light source.

[0011] Furthermore, the piezoelectric ceramic nozzle and the UV light source can move along the X, Y, and Z directions respectively, and the UV light source rapidly irradiates the printing liquid for photocuring after the microlens array printing is completed.

[0012] Furthermore, the printing liquid is a photocurable liquid material with a viscosity of 1-40 mPa·s, and the carrier liquid is any one of silicone oil, fluorinated liquid, and mineral oil. The printing liquid and the carrier liquid are immiscible, and the density of the printing liquid is greater than that of the carrier liquid.

[0013] Furthermore, the substrate is any one of polymethyl methacrylate, polycarbonate, or borosilicate glass, and the substrate is immersed in the carrier liquid and does not react with the carrier liquid.

[0014] Furthermore, the printing liquid consists of 0.5 wt% photoinitiator and 99.5 wt% polyethylene glycol diacrylate.

[0015] This technical solution also provides a fabrication method for the aforementioned microlens array manufacturing system, the method comprising the following steps:

[0016] S1. Start the back pressure source. The pressure in the storage bottle increases. The printing liquid flows along the liquid outlet tube into the piezoelectric ceramic glass sleeve. Adjust the output pressure of the back pressure source to stabilize the printing liquid at the nozzle outlet and form a stable interface with the carrier liquid at the nozzle.

[0017] S2. Start the editable excitation power supply. The editable excitation power supply generates a periodically changing voltage. Driven by the electrical signal, the piezoelectric actuator undergoes mechanical deformation, and the piezoelectric ceramic glass sleeve in the piezoelectric ceramic printhead deforms, thereby generating a pressure wave in the pipe, causing the printing liquid to be extruded and drawn back at the nozzle. When the piezoelectric ceramic printhead is subjected to a reasonable excitation waveform, the printing liquid in the printhead undergoes a process of extrusion, drawing back, and re-extrusion. During this process, the neck breaks, and the droplet eventually falls onto the substrate under the action of gravity in the carrier liquid.

[0018] S3. A printing droplet breaks apart and forms, which means that one microlens printing is completed. The piezoelectric ceramic nozzle moves to the next printing location under the control of the X, Y, and Z three-axis motion platform.

[0019] S4. Repeat the above steps. After each microlens printing is completed, the voltage change period and amplitude of the excitation power supply can be arbitrarily edited according to the size requirements of the next microlens. After the microlens droplet printing is completed, wait for all the printed droplets to fall onto the substrate to form a stable microlens shape;

[0020] S5. After the microlens array printing is completed, the piezoelectric ceramic nozzle is raised outside the liquid container and moved outside the substrate area by the X, Y, and Z three-axis motion platform. After the piezoelectric ceramic nozzle returns to its original position, the UV light source is moved above the printing area by the X, Y, and Z three-axis motion platform to perform photocuring on the printed liquid.

[0021] Furthermore, the programmable excitation power supply generates a periodically changing voltage with a period of 50μs and a voltage ranging from -100 to 100V.

[0022] By employing the above technical solution, the present invention provides a method and manufacturing system for preparing high-precision microlens arrays in a liquid environment, which has at least the following beneficial effects:

[0023] 1. This invention changes the fabrication environment of microlens arrays. During the printing process, the liquid carrier can effectively protect the droplets, which can avoid or alleviate problems such as volatilization and airflow affecting the shape of microlenses when using volatile printing materials, making the fabrication process of microlens arrays more stable.

[0024] 2. This invention enables the printing of multi-scale microlens arrays, allowing for the fabrication of microlenses of different sizes on the same substrate and optimizing their optical performance. It enables the control of microlens dimensions without altering the nozzle size using the same printhead, thus printing microlenses of varying sizes and reducing production costs. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0026] Figure 1 This is a schematic diagram of the microlens array manufacturing system in this invention;

[0027] Figure 2 For the present invention Figure 1 Enlarged view of point A in the middle;

[0028] Figure 3 This is a schematic diagram and a partial schematic diagram of the microlens array manufacturing system in this invention;

[0029] Figure 4 This is a schematic diagram of the internal structure of the piezoelectric ceramic nozzle in this invention and its connection with the programmable excitation power supply;

[0030] Figure 5 This is a schematic diagram of the printing process of high-precision micro / nano droplets using constrained interface vibration printing in this invention.

[0031] Figure 6 This is a schematic diagram of the microlens forming process in this invention;

[0032] Figure 7 This is a schematic diagram of the printing result of the microlens array in this invention;

[0033] Figure 8 This is a partial cross-sectional view of the microlens array printing result in this invention.

[0034] In the diagram: 1. Programmable excitation power supply; 2. Negative electrode wire; 3. Positive electrode wire; 4. Back pressure source; 5. Liquid storage bottle; 6. Bottle stopper; 7. Air inlet duct; 8. Liquid outlet duct; 9. Support frame; 10. Liquid carrier container; 11. UV light source X-direction slider; 12. Piezoelectric ceramic nozzle X-direction slider; 13. Y-direction slider; 14. Piezoelectric ceramic nozzle head clamp; 15. Piezoelectric ceramic nozzle lower clamp; 16. Piezoelectric ceramic nozzle Z-direction slider; 17. Piezoelectric ceramic nozzle; 18. UV light source upper clamp; 19. UV light source lower clamp; 20. UV light source Z-direction slider; 21. UV light source; 22. Piezoelectric actuator; 23. Piezoelectric ceramic glass sleeve; 24. Substrate; 25. Printing liquid; 26. Liquid carrier; 27. Microlens array. Detailed Implementation

[0035] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This will allow for a full understanding and implementation of how the present application uses technical means to solve technical problems and achieve technical effects.

[0036] Currently, the main methods for manufacturing microlens arrays include photolithography and mold replication. Photolithography uses photosensitive materials and ultraviolet light exposure combined with a photomask to create microlens arrays. First, a layer of photoresist is coated onto a substrate. Then, by controlling the light exposure and development process, the preliminary shape of the microlens is formed on the photoresist. Next, a thermal remelting technique is used to allow the photoresist to flow under heat and form a smooth curved surface to construct the lens structure. Photolithography can achieve high-precision, high-uniformity microlens arrays, but due to the complexity of the equipment, high cost, and the limited processing range of photoresist, it has certain limitations for large-area array production and the fabrication of thicker microlenses. Mold replication typically involves creating a master mold or prototype mold, and then using methods such as thermoforming, soft embossing, or injection molding to replicate the microlens structure onto the target substrate. This method is suitable for mass production, has lower costs, and the mold can be reused. However, the mold-making process is complex and costly, and the precision of the mold directly determines the quality of the replicated lens. In addition, microlens arrays are prone to structural deformation, material shrinkage, or surface defects during the replication process, especially for flexible substrates or large-sized microlens arrays, where accuracy and uniformity are difficult to guarantee.

[0037] Inkjet printing technology has garnered significant attention in recent years due to its high flexibility, uniformity, and material adaptability. This technology offers high design flexibility and digital control capabilities, making it suitable for applications requiring customization, rapid iteration, and small-batch production. Computer-aided design allows for precise control of lens size, shape, and arrangement, enabling on-demand deposition and eliminating the need for expensive mask fabrication processes. Furthermore, it allows for one-step UV curing, significantly simplifying the manufacturing process, improving material utilization, and offering lower equipment costs. This makes it suitable for rapid prototyping and small-batch customized production, and it can be applied to various substrates, greatly enhancing the design and application potential of microlens arrays. Currently, the mainstream inkjet printing process still operates in air, making it susceptible to the effects of gravity and surrounding airflow disturbances, which can interfere with the printing accuracy of microlenses. Moreover, with the increasing application of micro- and nano-optical components in modern optical imaging, optical communication, and displays, higher demands are placed on the manufacturing precision of microlens arrays. Conventional inkjet printing technologies improve printing accuracy by reducing nozzle size; however, smaller nozzles are prone to clogging during use, leading to significant manufacturing and maintenance costs.

[0038] The above-mentioned problems are technical challenges that urgently need to be solved in the application of inkjet printing technology to the field of microlens array printing. Please refer to... Figures 1-4 This embodiment proposes a microlens array manufacturing system that avoids or mitigates problems such as volatilization and airflow affecting the shape of microlenses during the fabrication process when using volatile printing materials, making the microlens array fabrication process more stable. The manufacturing system includes a liquid-carrying container 10 fixed to the central region of an X, Y, Z-axis motion platform via a support frame 9. The liquid-carrying container 10 contains a substrate 24 and stored liquid 26, and an editable excitation power supply 1 that drives a piezoelectric ceramic nozzle 17 with a variable electrical signal according to the required size for microlens fabrication. The editable excitation power supply can generate a periodically varying voltage from -100 to 100 volts, and the period and amplitude can be arbitrarily edited according to the required size for microlens production. The X, Y, Z-axis motion platform controls the piezoelectric ceramic nozzle 17 to generate droplets in the liquid 26 within the liquid-carrying container 10 through interface vibration, sequentially printing microlenses to form a microlens array 27. The nozzle of the piezoelectric ceramic nozzle 17 typically has an inner diameter of 50–100 μm.

[0039] In this embodiment, the piezoelectric ceramic nozzle 17 includes a piezoelectric actuator 22 mounted on the outer wall of the piezoelectric ceramic glass sleeve 23. The piezoelectric ceramic glass sleeve 23 is filled with printing liquid 25. The electrical signal generated by the programmable excitation power supply 1 drives the piezoelectric actuator 22 to produce mechanical deformation, causing the piezoelectric ceramic glass sleeve 23 to be in an expanding or contracting state while generating negative or positive pressure waves within it. Under the cyclic action of negative and positive pressure waves, the neck of the printing liquid 25 breaks during the process of extrusion, re-suction, and re-extrusion. The droplets fall onto the substrate 24 in the carrier liquid 26 with their own gravity to form microlenses.

[0040] As a further implementation option of this embodiment, the negative pressure wave or the positive pressure wave is split into two and propagates synchronously to both sides along the inner channel of the piezoelectric ceramic glass sleeve 23. Initially, driven by an electrical signal, the piezoelectric actuator 22 propagates two negative pressure waves from the middle of the piezoelectric ceramic glass sleeve 23 to both ends. One negative pressure wave reaches the nozzle end of the piezoelectric ceramic glass sleeve 23, causing the printing liquid 25 to be drawn back. The other negative pressure wave simultaneously reaches the open end and undergoes opposite reflection to form a reflected wave. Subsequently, the programmable excitation power supply 1 drives the piezoelectric ceramic glass sleeve 23 to contract, generating a positive pressure wave in the channel. One of the two positive pressure waves is linearly superimposed with the reflected wave and moves towards the nozzle end to extrude the printing liquid 25. The other positive pressure wave propagating towards the open end cancels out the negative pressure wave. In this embodiment, the piezoelectric ceramic nozzle drives the piezoelectric actuator 22 to generate mechanical deformation through the programmable excitation power supply 1, causing the piezoelectric ceramic glass sleeve 23 to be in an expanding or contracting state while generating negative or positive pressure waves within it to prepare the microlens. The working principle is as follows:

[0041] The inner cavity of the piezoelectric ceramic glass sleeve 23 can be considered as a cylindrical acoustic waveguide. When the excitation frequency of the acoustic wave inside the pipe is less than the pipe's cutoff frequency, its propagation within the pipe can be considered as a plane wave. (Cutoff frequency) The calculation formula is:

[0042] ;

[0043] In the formula, The nozzle channel radius of the piezoelectric ceramic nozzle; This represents the speed at which sound waves propagate inside the pipe.

[0044] The corresponding cutoff frequency can be obtained from the above formula. The frequency is much higher than the excitation frequency of piezoelectric ceramics, therefore the sound waves in the channel can be considered as plane waves. In summary, the sound waves in the nozzle channel can be analyzed as linear one-dimensional plane sound waves, satisfying the principle of linear superposition. Let there be an incident wave... The cross-sectional area is The cross-sectional area of ​​the pipe is The incident wave propagates within a pipe where the medium is the same on both sides of the abrupt change in the pipe's cross-section. exist and At the interface, reflection and transmission occur, corresponding to the reflected wave, respectively. and transmitted waves The corresponding particle velocities are expressed as follows: , and There are two boundary conditions at the interface. The first is that the sound pressure is continuous, i.e.: ;

[0045] Secondly, according to the law of conservation of mass, the condition for continuity of volume velocity should be satisfied, that is:

[0046] ;

[0047] Combining the two equations, the sound pressure ratio can be obtained as:

[0048] ;

[0049] From the above formula, it can be seen that the reflection of sound waves is related to the ratio of the cross-sectional areas of the two tubes. When hour, It can be seen that the reflected pressure wave will change from positive to negative or from negative to positive; this is the case of pressure wave reflection at the opening end. hour, The sound wave will be completely reflected and its properties will remain unchanged, which is the case when the pressure wave is reflected at the nozzle end.

[0050] Based on the above principle, in this embodiment, a drive signal is applied at the initial moment through the programmable excitation power supply 1, causing the piezoelectric ceramic glass sleeve 23 to expand, thereby forming a negative pressure wave inside the piezoelectric ceramic glass sleeve 23. This wave splits into two and propagates synchronously along both sides of the pipe. When the negative pressure wave reaches the closed end, it causes a slight backflow at the nozzle interface. Since the size of the nozzle is much smaller than the size of the piezoelectric ceramic glass sleeve 23, the pressure wave undergoes same-sign reflection at the nozzle end (which can be considered the closed end), that is, the nature of the pressure wave remains unchanged, but the direction of motion is reversed. At the same time, the negative pressure wave moving in the other direction reaches the open end, and the pressure wave undergoes opposite-sign reflection, that is, the nature of the pressure wave changes (the negative pressure wave is reflected as a positive pressure wave), and the direction of motion is also reversed.

[0051] Subsequently, the editable excitation power supply 1 drives the piezoelectric ceramic glass sleeve 23 to contract, generating a positive pressure wave within the tube. This wave also splits into two and propagates synchronously to both sides. By adjusting the duration of the editable excitation power supply 1, the moment the pressure waves reflected from both sides meet in the middle can correspond to the moment the positive pressure wave is applied, allowing for effective superposition of the reflected wave and the pressure wave at that moment. In this case, the positive and negative pressure waves propagating towards the opening cancel each other out, while the two positive pressure waves moving towards the nozzle end undergo linear superposition, resulting in enhanced energy and a more noticeable ejection of the printing liquid when the pressure wave reaches the nozzle.

[0052] Finally, the pressure wave reciprocates within the piezoelectric ceramic glass sleeve 23 and gradually weakens. Each time the pressure wave reaches the nozzle end, it undergoes a reflection of the same sign, meaning the nature of the pressure wave remains unchanged, but its direction of motion reverses. When it reaches the opening end, the pressure wave undergoes a reflection of the opposite sign, meaning the nature of the pressure wave changes (a negative pressure wave is reflected as a positive pressure wave), and its direction of motion also reverses. This causes the printing liquid to repeatedly experience ejection and retraction.

[0053] As a further implementation option of this embodiment, the X, Y, Z three-axis motion platform includes a UV light source X-direction slider 11, a piezoelectric ceramic nozzle X-direction slider 12, a Y-direction slider 13, a piezoelectric ceramic nozzle Z-direction slider 16, and a UV light source Z-direction slider 20. The piezoelectric ceramic nozzle Z-direction slider 16 is equipped with a piezoelectric ceramic nozzle upper clamp 14 and a piezoelectric ceramic nozzle lower clamp 15 to fix the piezoelectric ceramic nozzle 17. The UV light source Z-direction slider 20 is equipped with a UV light source upper clamp 18 and a UV light source lower clamp 19 to fix the UV light source 21. The piezoelectric ceramic nozzle 17 and the UV light source 21 can move along the X, Y, and Z directions respectively. After the microlens array printing is completed, the UV light source 21 rapidly irradiates the printing liquid 25 for photocuring.

[0054] More specifically, the X, Y, and Z three-axis motion platform controls the piezoelectric ceramic nozzle 17 to achieve precise positioning and continuous movement to complete the microlens array printing task by converting G-code instructions into specific motion control signals.

[0055] More specifically, the bottle 5 has a stopper 6 at its mouth, leaving only two insertion holes for the conduits, thus isolating the inside of the bottle from the outside air. The bottle contains printing liquid 25. The back pressure source 4 is connected to the air inlet conduit 7, which is inserted into the bottle 5. The end of the air inlet conduit 7 is not inserted into the printing liquid 25, but is kept at a certain distance from the liquid surface. The liquid outlet conduit 8 is inserted into the printing liquid 25. Under the drive of the back pressure source 4, the printing liquid 25 is transferred to the piezoelectric ceramic nozzle 17 through the liquid outlet conduit 8.

[0056] The printing liquid 25 is a photocurable liquid material with a viscosity of 1-40 mPa·s, exhibiting high optical transparency and stability, and is stored in the storage bottle 5. The printing liquid 25 consists of 0.5 wt% photoinitiator and 99.5 wt% polyethylene glycol diacrylate. The carrier liquid 26 is any one of silicone oil, fluorinated liquid, or mineral oil; silicone oil is further used as the carrier liquid 26, and it is stored in the carrier container 10. The printing liquid 25 and the carrier liquid 26 are immiscible, and the density of the printing liquid 25 is greater than that of the carrier liquid 26. The contact angle between the microlens array and the substrate is adjusted according to requirements before printing. The substrate 24 can be one of polymethyl methacrylate, polycarbonate, or borosilicate glass; the substrate can be selected according to specific printing needs. More specifically, polymethyl methacrylate is selected as the substrate 24, and the substrate 24 is hydrophilically treated before printing. The substrate 24 is immersed in the carrier liquid 26 and does not react with the carrier liquid 26.

[0057] like Figure 4 As shown, the programmable excitation power supply 1 connects the positive signal output terminal to the outer wall electrode of the piezoelectric actuator 22 through the positive wire 3, and connects the negative signal output terminal to the inner wall electrode of the piezoelectric actuator 22 through the negative wire 2, so as to realize the electrical signal drive of the piezoelectric ceramic nozzle 17.

[0058] like Figures 5-8 As shown, based on the aforementioned microlens array manufacturing system, this embodiment also proposes a fabrication method to be used in conjunction with the above-mentioned system to fabricate a microlens array. This method includes the following steps:

[0059] S1. Store printing liquid 25 in storage bottle 5, place the substrate in liquid carrier container 10 and add sufficient liquid carrier 26, the depth of liquid carrier 26 reaches 500μm.

[0060] S2. Select a piezoelectric ceramic nozzle 17 with a nozzle size of 60μm. Adjust the piezoelectric ceramic nozzle 17 to one corner of the substrate 24, with a distance of 20μm from both sides of the substrate 24 and a distance of 120μm from the nozzle to the substrate. Set this position as the origin for starting printing and input the designed G code into the X, Y, and Z three-axis motion platform.

[0061] S3. Start the back pressure source 4, the pressure in the liquid storage bottle 5 increases, the printing liquid 25 flows along the liquid outlet pipe 8 into the piezoelectric ceramic glass sleeve 23, and the liquid level is stabilized at the nozzle outlet.

[0062] S4. Start the editable excitation power supply 1. The editable excitation power supply 1 generates a periodic voltage with a period of 50μs and a voltage of -100-100V, such as... Figure 5As shown, the piezoelectric actuator 22 undergoes mechanical deformation under the drive of an electrical signal, which directly causes a certain degree of deformation in the piezoelectric ceramic glass sleeve 23, generating a pressure wave inside the tube. When the piezoelectric actuator 22 squeezes inward, it causes the printing liquid 25 to be extruded; when the piezoelectric actuator 22 expands outward, it causes the printing liquid 25 to be drawn back in. When the printing liquid 25 in the piezoelectric ceramic nozzle 17 breaks at the neck during the process of extrusion, drawing back in, and then extrusion again, the droplet eventually falls onto the substrate 24 under the action of gravity in the carrier liquid 26.

[0063] S5, such as Figure 6 As shown, a printing droplet breaks apart to form, which means that one microlens printing is completed. The piezoelectric ceramic nozzle 17 will move 90μm along the X direction with the XYZ three-axis motion platform to the next printing location. The droplet in the carrier liquid 26 will eventually fall onto the substrate 24 under the action of gravity.

[0064] S6. Repeat the above steps to print a row of five microlenses on the substrate 24 along the X direction. Then, move the X, Y, and Z three-axis motion platform 90 μm along the Y direction to the next printing location. Edit the excitation power supply 1 to change the voltage change period and amplitude, and continue the microlens printing task.

[0065] S7. After all the droplets have fallen onto the substrate 24 and the lens shape has stabilized, turn on the UV light source 21 and irradiate for 2 minutes to complete the curing. Then, turn off the UV light source 21, the programmable excitation power supply 1, and the back pressure source 4 in sequence. Finally, remove the microlens array 27. Figure 7 and Figure 8 As shown.

[0066] This embodiment enables the printing of multi-scale microlens arrays, allowing for the fabrication of microlenses of different sizes on the same substrate and optimizing their optical performance. It achieves the ability to control the size of microlenses without changing the nozzle size using the same printhead, thus printing microlenses of different sizes and reducing production costs.

[0067] This embodiment changes the fabrication environment of the microlens array. During the printing process, the liquid carrier can effectively protect the droplets, which can avoid or alleviate problems such as volatilization and airflow affecting the shape of the microlens when using volatile printing materials, making the fabrication process of the microlens array more stable.

[0068] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Since the above embodiments are substantially similar to the method embodiments, their descriptions are relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0069] The above embodiments provide a detailed description of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A manufacturing system for a microlens array, comprising a liquid-carrying container (10) fixed to the central region of an X, Y, Z three-axis motion platform by a support frame (9), wherein a substrate (24) and a stored liquid (26) are disposed within the liquid-carrying container (10), and a programmable excitation power supply (1) for adjusting the pressure within a piezoelectric ceramic nozzle (17) according to the required dimensions for microlens fabrication, characterized in that, The X, Y, Z three-axis motion platform controls the piezoelectric ceramic nozzle (17) to generate droplets in the liquid (26) in the liquid container (10) through interface vibration to print microlenses in sequence to form a microlens array (27). The piezoelectric ceramic nozzle (17) includes a piezoelectric actuator (22) installed on the outer wall of the piezoelectric ceramic glass sleeve (23). The piezoelectric ceramic glass sleeve (23) is filled with printing liquid (25). The electrical signal generated by the programmable excitation power supply (1) drives the piezoelectric actuator (22) to produce mechanical deformation, so that the piezoelectric ceramic glass sleeve (23) is in an expanding or contracting state and generates a negative pressure wave or a positive pressure wave inside it. Under the cyclic action of the negative pressure wave and the positive pressure wave, the neck of the printing liquid (25) breaks during the process of extrusion, back suction and re-extrusion. The droplets fall on the substrate (24) in the carrier liquid (26) with their own gravity to form microlenses. The printing liquid (25) is a photocurable liquid material with a viscosity of 1-40 mPa·s. The carrier liquid (26) is any one of silicone oil, fluorinated liquid, and mineral oil. The printing liquid (25) and the carrier liquid (26) are immiscible, and the density of the printing liquid (25) is greater than that of the carrier liquid (26). The printing liquid (25) is composed of 0.5 wt% photoinitiator and 99.5 wt% polyethylene glycol diacrylate. The programmable excitation power supply generates a periodically changing voltage with a period of 50μs and a voltage ranging from -100 to 100V. The X, Y, Z three-axis motion platform includes a UV light source X-direction slider (11), a piezoelectric ceramic nozzle X-direction slider (12), a Y-direction slider (13), a piezoelectric ceramic nozzle Z-direction slider (16), and a UV light source Z-direction slider (20). The piezoelectric ceramic nozzle Z-direction slider (16) is equipped with a piezoelectric ceramic nozzle upper clamp (14) and a piezoelectric ceramic nozzle lower clamp (15) to fix the piezoelectric ceramic nozzle (17). The UV light source Z-direction slider (20) is equipped with a UV light source upper clamp (18) and a UV light source lower clamp (19) to fix the UV light source (21).

2. The microlens array manufacturing system according to claim 1, wherein The negative pressure wave or positive pressure wave splits into two and propagates synchronously to both sides along the inner pipe of the piezoelectric ceramic glass sleeve (23); At the initial moment, driven by the electrical signal, the piezoelectric actuator (22) generates two negative pressure waves that propagate from the middle of the piezoelectric ceramic glass sleeve (23) to both ends. One of the negative pressure waves reaches the nozzle end of the piezoelectric ceramic glass sleeve (23), causing the nozzle end to draw back the printing liquid (25). The other negative pressure wave simultaneously reaches the opening end and is reflected by opposite signs to form a reflected wave. One of the two positive pressure waves is linearly superimposed with the reflected wave and moves toward the nozzle end to extrude the printing liquid (25), while the other positive pressure wave propagates toward the opening end and cancels out the negative pressure wave.

3. The microlens array manufacturing system according to claim 1, wherein The piezoelectric ceramic nozzle (17) and the UV light source (21) can move along the X, Y, and Z directions respectively. The UV light source (21) quickly irradiates the printing liquid (25) for photocuring after the microlens array printing is completed.

4. The microlens array manufacturing system according to claim 1, wherein The substrate (24) is any one of polymethyl methacrylate, polycarbonate, or borosilicate glass, and the substrate (24) is immersed in the carrier liquid (26) and does not react with the carrier liquid (26).

5. A method for manufacturing microlenses to be used in the microlens array manufacturing system according to any one of claims 1 to 4, characterized by The method includes the following steps: S1. Start the back pressure source. The pressure in the storage bottle increases. The printing liquid flows along the liquid outlet tube into the piezoelectric ceramic glass sleeve. Adjust the output pressure of the back pressure source to stabilize the printing liquid at the nozzle outlet and form a stable interface with the carrier liquid at the nozzle. S2. Start the editable excitation power supply. The editable excitation power supply generates a periodically changing voltage. The piezoelectric actuator undergoes mechanical deformation under the drive of the electrical signal. The piezoelectric ceramic glass sleeve in the piezoelectric ceramic nozzle deforms, thereby generating a pressure wave in the pipe, causing the printing liquid to be squeezed out and sucked back at the nozzle. S3. A printing droplet breaks apart and forms, which means that one microlens printing is completed. The piezoelectric ceramic nozzle moves to the next printing location under the control of the X, Y, and Z three-axis motion platform. S4. Repeat the above steps. After each microlens printing is completed, the voltage change period and amplitude of the excitation power supply can be edited arbitrarily according to the size requirements of the next microlens. After the piezoelectric ceramic printhead returns to its original position, the S5 UV light source is moved above the printing area by the X, Y, and Z three-axis motion platform to perform photocuring on the printing liquid.

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