Preparation method for morphology-controllable microlens array, microlens array, use, and 3D printing device

Abstract

The present invention relates to the technical field of 3D printing devices, and relates to a preparation method for a morphology-controllable microlens array, a microlens array, a use, and a 3D printing device. The preparation method comprises the following steps: S1. on the basis of a microlens array to be printed, forming, on a substrate, a defining layer with a pattern consistent with that of the microlens array; S2. printing the microlens array on the substrate by using a microlens glue solution material; and S3, curing the microlens array to obtain a microlens array finished product. According to the preparation method for a microlens array provided by the present invention, the operation is simple, defining layers with different patterns can be designed on the basis of the morphologies of different microlens arrays, the preparation of different microlens arrays is met, and a variety of bases can be adapted to prepare array microlenses. The shape and size of an obtained microlens array are more accurate, and the accuracy can reach within 0.5 micrometer.

Description

Preparation method of controllable morphology microlens array, microlens array, application and 3D printing equipment Technical Field

[0001] The present invention belongs to the field of optical instrument manufacturing and relates to a method for preparing an array microlens, in particular to a method for preparing a controllable morphology microlens array, a microlens array, an application and a 3D printing device. Background Art

[0002] Microlens arrays consist of a series of array elements with diameters ranging from micrometers to millimeters arranged according to a specific pattern. They can achieve a wide range of optical functions within a small area. By adjusting the shape, curvature, and spacing of the lenses, different optical effects such as focusing, magnification, transformation, and segmentation can be achieved. They also feature high optical efficiency and low loss, improving the performance of optical systems. Therefore, microlens arrays have a wide range of applications. In the imaging field, they can be used for high-resolution image acquisition, optical microscopy, and spectral imaging. In optical communications, microlens arrays can be used for beam shaping, optical path alignment, and optical coupling. In the field of optical sensing, they can be used to implement microsensors and fiber optic sensors. Microlens arrays also have applications in optical displays, laser processing, and biomedicine.

[0003] Currently, the main methods for fabricating spherical microlenses include mechanical machining, thermal reflow, and spraying. Mechanical machining involves obtaining a mold through precision machining, followed by molding through injection molding or nanoimprinting to create an array of microlenses. This method requires high mold morphology accuracy, and can also present precision issues during actual demolding or imprinting. The thermal reflow method involves exposing photoresist to a cylindrical or arrayed columnar morphology, then heating it to a glassy state and softening it. This allows the photoresist to spontaneously form microlenses under the influence of surface tension. However, due to the high fluidity of photoresist at high temperatures, the microlens morphology varies significantly at different locations due to the influence of the environment and heating uniformity, resulting in poor overall uniformity. The spraying method uses a precise nozzle and a precise position control platform to spray glue through the nozzle, forming droplets in the shape of microlenses on the substrate surface. This method is highly efficient and simple to operate, but it has the disadvantage of requiring strong compatibility between the material and substrate to form a stable, adherent microlens structure.

[0004] In recent years, the development of 3D printing technology has brought new possibilities for the fabrication of microlens arrays.

[0005] For example, CN107009613A discloses a method for manufacturing a microlens array based on 3D direct writing. This method uses a 3D direct writing device to sequentially write a microlens precursor array at predetermined array positions perpendicular to the surface of a transparent substrate. The microlens precursor array is then processed through a hot melt process, relying on surface tension to form the microlens array. This method solves the lens surface step and internal interface layer issues that often occur with 3D printing.

[0006] As the application range of microlens arrays expands towards precision, existing technologies are placing increasing demands on the precision of microlens arrays. The aforementioned manufacturing method, which directly applies pressure to bond a liquid solution to the surface of a transparent substrate before printing, suffers from poor positional control of the microlens precursors, requiring further improvement. Furthermore, strong compatibility between the material and substrate is required to achieve a stable, adherent microlens array.

[0007] Prior art methods for precisely printing microlenses employ positioning grooves on a substrate. For example, CN108732661A uses photolithography to create a black circular hole groove array (i.e., a circular hole array), which is then used for positioning. Then, inkjet printing is performed using a low-viscosity, high-transmittance UV resin as ink onto the cleaned black circular hole array. However, in practice, this improvement in precision is limited, and further improvements depend on the accuracy of the printing equipment. Summary of the Invention

[0008] The purpose of the present invention is to solve the accuracy problem existing in the current microlens array preparation process and to provide a method for preparing a microlens array with controllable morphology.

[0009] The present invention adopts the following technical solutions:

[0010] A method for preparing a microlens array with controllable morphology comprises the following steps:

[0011] S1. According to the microlens array to be printed, a defining layer having a pattern consistent with the microlens array is formed on the substrate;

[0012] S2 using a microlens glue material printed on the substrate microlens array;

[0013] S3. Curing the microlens array to obtain a finished microlens array.

[0014] As a preferred embodiment of the above technical solution, the defining layer forms a groove on the substrate that is consistent with the microlens array, and there is a first mutually repulsive force between the material of the defining layer and the microlens glue material, and the microlens array is obtained based on the first force and the position of the groove.

[0015] As a preferred embodiment of the above technical solution, the first force includes one or more of intermolecular force, magnetic force or electrostatic force.

[0016] In the solution of the present invention, a defining layer is formed on a substrate. The defining layer's pattern is designed based on the microlens array, and an array of grooves is formed at positions corresponding to the microlenses. The microlens array is then printed on the defining layer. The grooves not only position the printed microlenses, but also restrict the adhesive material of the microlenses, resulting in more precise shapes and sizes of the printed microlenses, particularly enabling precise control of their height.

[0017] The guarantee of high precision in the above solution also depends on the precision of the printing device. Under the conditions of the precision of the printing device in the current existing technology, the highest precision can only reach 5 microns.

[0018] The above technical solution further selects the material of the defining layer to form a certain interaction force with the microlens adhesive material, such as intermolecular force, magnetic force, or electrostatic force. This solution, by selecting the material and leveraging the interaction force between the defining layer and the microlens adhesive, can help accurately position the microlens adhesive within the grooves, achieving high printing accuracy. Even if the printing device's print head deflects, the microlens can still be accurately positioned and the adhesive material can be printed within the grooves of the defining layer. Accuracy can reach within 0.5 microns.

[0019] The above technical solution, through the provision of a limiting layer and the further selection of the limiting layer material, can also achieve effective control of the microlens height. Because printing uses a glue material, controlling the microlens height is a difficult aspect of 3D printing. The provision of a limiting layer in the present invention not only limits the width of the microlens in the horizontal direction, but also improves the accuracy of height control by leveraging the interaction between the limiting layer material and the microlens glue material. This further facilitates precise control of the microlens size.

[0020] As a preferred embodiment of the above technical solution, the main component of the material of the limiting layer is polyimide, and the material of the microlens array is acrylic resin.

[0021] As a preferred embodiment of the above technical solution, the limiting layer is polyimide photoresist, which is formed on the substrate by photolithography.

[0022] Polyimide photoresist is a high-performance photoresist material with many advantages. These include, but are not limited to, the following: High Resolution: Polyimide photoresist has excellent resolution, enabling the fabrication of microstructures. It can achieve submicron pattern definition, making it suitable for the manufacture of high-density integrated circuits and other micro-nano devices. High Sensitivity: Polyimide photoresist has high sensitivity to ultraviolet light, which can speed up the photolithography process and improve production efficiency. It can form patterns within a shorter exposure time, saving manufacturing time and costs. Excellent Chemical Stability: Polyimide photoresist has good chemical stability and can be used in a variety of manufacturing environments while providing reliable pattern definition.

[0023] In the present invention, the polyimide photoresist is selected to give full play to its own advantages and manufacture a defining layer that is more conducive to the shape and size of the microlens.

[0024] The polyimide photoresist is any one of FUJIFILM's LTC9000 series, FB5610, FB6610 and DUR7300, Asahi Kasei Corporation BL-301, JSR ELPAC WPR-5100, SUMIRESIN EXCEL® CRC-8300 series, HD MicroSystems' HD-4100 series, Allresist GmbH's SX AR-PC 5000 / 82, etc.

[0025] As a preferred embodiment of the above technical solution, the thickness of the defining layer is 0.5μm to 15μm. During the printing and preparation process of the microlens array, the thickness of the defining layer also has a significant impact on the dimensional accuracy of the microlenses. When the defining layer thickness is less than 0.5μm, it is difficult to maintain the shape and size of the microlens array, and the control accuracy of the microlens pitch and height is poor. When the defining layer thickness is greater than 15μm, the excessively high defining layer is not conducive to controlling the height of the microlenses.

[0026] During the printing process of the array microlens, in order to better control the shape and size of the microlens array and broaden the control range of the microlens height, the thickness of the defining layer is preferably set between 0.5 μm and 5 μm.

[0027] As a preferred embodiment of the above technical solution, the printing method is ink direct writing printing or electrohydrodynamic inkjet printing, inkjet printing, or piezoelectric printing.

[0028] As a preferred embodiment of the above technical solution, step S2 further includes:

[0029] Obtaining printing parameters of the microlens array;

[0030] Positioning the edge of the substrate by using a visual device;

[0031] Setting a printing mode according to the printing parameters to print the microlens array once or multiple times,

[0032] The printing parameters include microlens height, microlens width and microlens spacing.

[0033] The present invention also provides a microlens array prepared by the above-mentioned preparation method. The obtained microlens array has more precise shape and size, with an accuracy of less than 0.5 microns.

[0034] By implementing the above technical solution, the present invention forms a limiting layer on the substrate, uses the limiting layer to position the printing of the microlens, and can also limit the glue material of the microlens, so that the shape and size of the printed microlens are more accurate.

[0035] Furthermore, the present invention can further improve printing accuracy by selecting the limiting layer material, and can achieve a maximum accuracy of no more than 0.5 microns even when the printing equipment lacks accuracy.

[0036] The present invention also provides applications of the microlens array, which can be applied to naked-eye 3D, anti-peeping display devices, and the like.

[0037] The present invention also provides a preparation device for implementing the above-mentioned microlens array preparation method.

[0038] The present invention's method for preparing a microlens array is simple to operate and can design defining layers with different patterns based on the morphology of the microlens array, meeting the requirements for preparing different microlens arrays. Furthermore, it can be adapted to a variety of substrates for preparing arrayed microlenses. The resulting microlens array has more precise shape and size, achieving an accuracy of less than 0.5 microns. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG1 is a flow chart of the preparation method of the microlens array according to Example 1.

[0040] FIG2 shows a microlens unit prepared by the preparation method described in Example 1.

[0041] FIG3 shows a microlens unit prepared by the preparation method described in Example 2.

[0042] FIG4 shows a microlens unit prepared by the preparation method described in Example 3.

[0043] FIG5 is a flow chart of preparing a microlens array using the preparation method described in Example 4.

[0044] 6A-6F show microlens units of different heights prepared by the preparation method described in Example 5.

[0045] 7A-7E are partial electron micrographs of microlens arrays with different gaps obtained by the preparation method described in Example 7.

[0046] FIG8 is an electron microscope image of a portion of the microlens array obtained by the preparation method described in Comparative Example 2.

[0047] In the figure, 1-substrate, 2-limiting layer, 3-microlens array, 4-printing needle. Implementation Method

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] Example 1 This example aims to print a microlens array with a microlens pitch (center-to-center distance between two adjacent lenses) of 181.8 μm, a microlens width of 133.5 μm, and a microlens height of 44.5 μm. The preparation is performed as follows.

[0050] A method for preparing a microlens array comprises the following steps:

[0051] S1. Design and manufacture a defining layer according to the size of the microlens array to be printed. The defining layer has grooves that are consistent with the microlenses of the microlens array, and the spacing between adjacent grooves is the spacing between adjacent microlenses.

[0052] S2. Using photolithography technology, a pattern of a defining layer is developed on a clean glass substrate to obtain a glass substrate for 3D printing. The defining layer uses LTC 9305 from the LTC9000 series of FUJIFILM Corporation, and the thickness of the defining layer is 0.5 microns.

[0053] S3. Prepare the microlens adhesive material, load it into a 3mL cartridge, mount it on the 3D printing platform, and attach the printing needle. The adhesive material is an acrylic ester UV adhesive containing approximately 50% acrylic resin, 48% acrylate monomer, 1% photoinitiator, and 1% rheological additive.

[0054] Obtaining printing parameters of the microlens array including microlens height, microlens width, and microlens spacing;

[0055] The visual device of the 3D printing equipment is used to grasp and position the edge of the glass substrate, and the precision motion platform is used to ensure that the needle is aligned with the middle of the limiting layer, and the material is printed in the limiting layer, as shown in Figure 1;

[0056] Setting a printing mode according to the printing parameters to print and solidify the microlens array;

[0057] The scanning electron microscope image of the obtained microlens array is shown in Figure 2. The actual microlens array obtained has a microlens pitch of 181.8 μm, a microlens width of 133.5 μm, and a microlens height of 44.7 μm.

[0058] Example 2 This example aims to print a microlens array with a microlens pitch of 181.8 μm, a microlens width of 88.5 μm, and a microlens height of 16.0 μm. The preparation is carried out according to the following method.

[0059] A method for preparing a microlens array comprises the following steps:

[0060] S1. A patterned defining layer is manufactured by design, wherein the defining layer has grooves corresponding to the microlens units of the microlens array, and the spacing between adjacent grooves is the spacing between adjacent microlenses.

[0061] S2. Using photolithography technology, a defining layer pattern is developed on a cleaned glass substrate to obtain a glass substrate for 3D printing. The defining layer uses LTC 9320 from FUJIFILM's LTC9000 series, and the thickness of the defining layer is 1.25 microns.

[0062] S3. Prepare the microlens adhesive material, load it into a 3mL cartridge, install it on the 3D printing platform, and attach the printing needle. The adhesive material is an acrylic ester UV adhesive, containing approximately 50% acrylic resin, approximately 48% acrylate monomer, approximately 1% photoinitiator, and approximately 1% rheological additive.

[0063] Obtaining printing parameters of the microlens array including microlens height, microlens width, and microlens spacing;

[0064] The glass substrate is positioned by grasping the edge through the visual device of the 3D printing equipment, and the needle is aligned with the middle of the limiting layer through the precision motion platform to print the material within the limiting layer;

[0065] The microlens array was printed and cured according to the printing parameters. The scanning electron microscope image of the obtained microlens array is shown in Figure 3. The microlens pitch was 181.8 μm, the microlens width was 88.5 μm, and the microlens height was 16.3 μm.

[0066] Example 3 This example aims to print a microlens array with a microlens pitch of 181.8 μm, a microlens width of 88.5 μm, and a microlens height of 16.0 μm. The preparation is carried out according to the following method.

[0067] A method for preparing a microlens array comprises the following steps:

[0068] S1. A patterned defining layer is manufactured by design, wherein the defining layer has grooves corresponding to the microlens units of the microlens array.

[0069] S2. Using photolithography, a defining layer pattern is developed on a cleaned glass substrate to obtain a glass substrate for 3D printing. Fujifilm's LTC9320 LTC9000 series printer is used. The defining layer has a thickness of 12 microns.

[0070] S3. Prepare the microlens adhesive material, load it into a 3mL cartridge, install it on the 3D printing platform, and attach the printing needle. The adhesive material is an acrylic ester UV adhesive, containing approximately 50% acrylic resin, approximately 48% acrylate monomer, approximately 1% photoinitiator, and approximately 1% rheological additive.

[0071] Obtaining printing parameters of the microlens array including microlens height, microlens width, and microlens spacing;

[0072] The glass substrate is positioned by grasping the edge through the visual device of the 3D printing equipment, and the needle is aligned with the middle of the limiting layer through the precision motion platform to print the material within the limiting layer;

[0073] The microlens array was printed and cured according to the printing parameters. The scanning electron microscope image of the obtained microlens array is shown in Figure 4. The microlens pitch was 181.8 μm, the microlens width was 88.5 μm, and the microlens height was 16.2 μm.

[0074] Example 4 is different from Example 1 in that, in step S5 , the needle is deliberately deviated from one side of the limiting layer by 30 μm through a precision motion platform, and the material is printed in the limiting layer, as shown in FIG5 .

[0075] The microlens array actually obtained has a microlens pitch of 181.8 μm, a microlens width of 133.2 μm, and a microlens height of 26 μm.

[0076] It can be seen from the test data of this embodiment that even if the printing device has poor precision, a microlens array with excellent precision can be obtained by the preparation method of this embodiment. This preparation method can make up for the lack of precision of the printing device.

[0077] Example 5 This example aims to print a microlens array with a microlens pitch of 181.8 μm, a microlens width of 133.5 μm, and a series of heights. The preparation is carried out according to the following method.

[0078] A method for preparing a microlens array comprises the following steps:

[0079] S1. Design and manufacture a defining layer according to the size of the microlens array to be printed. The defining layer has grooves corresponding to the microlens units of the microlens array, and the spacing between adjacent grooves is the spacing between adjacent microlenses.

[0080] S2. Using photolithography technology, a pattern of a defining layer is developed on a cleaned glass substrate to obtain a glass substrate for 3D printing. The defining layer uses LTC 9305 from the LTC9000 series of FUJIFILM Corporation, and the thickness of the defining layer is 1.25 microns.

[0081] S3. Prepare the microlens adhesive material, load it into a 3mL cartridge, mount it on the 3D printing platform, and attach the printing needle. The adhesive material is an acrylic ester UV adhesive containing approximately 50% acrylic resin, 48% acrylate monomer, 1% photoinitiator, and 1% rheological additive.

[0082] Obtaining printing parameters of the microlens array including microlens height, microlens width, and microlens spacing;

[0083] The visual device of the 3D printing equipment is used to grasp and position the edge of the glass substrate, and the precision motion platform is used to ensure that the needle is aligned with the middle of the limiting layer, and the material is printed within the limiting layer;

[0084] The microlens array was printed and cured according to the printing parameters. Scanning electron microscope images of the resulting microlens array are shown in Figures 6A-6F. The actual and designed values ​​of the microlens width and height are shown in Table 1.

[0085] Table 1 - Actual and designed values ​​of the width and height of the microlens obtained in this embodiment

[0086]

[0087] It can be seen from the microlens size data obtained in this embodiment that by implementing the preparation method of this embodiment, the height, width and spacing of the obtained microlenses can be controlled within an accuracy of less than 0.5 μm. In particular, the preparation method can effectively control the height of the microlenses.

[0088] Example 6 This example aims to print a microlens array with a microlens pitch of 181.8 μm, a microlens width of 133.5 μm, and a microlens height of 27.20 μm. The microlens array is prepared according to the following method.

[0089] A method for preparing a microlens array comprises the following steps:

[0090] S1. Design and manufacture a defining layer according to the size of the microlens array to be printed. The defining layer has grooves corresponding to the microlens units of the microlens array, and the spacing between adjacent grooves is the spacing between adjacent microlenses.

[0091] S2. Using photolithography technology, a pattern of a defining layer is developed on a clean glass substrate to obtain a glass substrate for 3D printing. The defining layer uses LTC 9305 from the LTC9000 series of FUJIFILM Corporation, and the thickness of the defining layer is 2.0 microns.

[0092] S3. Prepare the microlens adhesive material, load it into a 3mL cartridge, install it on the 3D printing platform, and attach the printing needle. The adhesive material is an acrylic ester UV adhesive, containing approximately 50% acrylic resin, approximately 48% acrylate monomer, approximately 1% photoinitiator, and approximately 1% rheological additive.

[0093] Obtaining printing parameters of the microlens array including microlens height, microlens width, and microlens spacing;

[0094] The visual device of the 3D printing equipment is used to grasp and position the edge of the glass substrate, and the precision motion platform is used to ensure that the needle is aligned with the middle of the limiting layer, and the material is printed within the limiting layer;

[0095] The microlens array is printed and cured according to the printing parameters to obtain a microlens array. The microlens height is tested at multiple points, and the results are shown in Table 2.

[0096] Table 2 - Height values ​​of microlenses obtained in this embodiment

[0097]

[0098] As can be seen from Table 2, using the preparation method of Example 5, the microlenses prepared have good height stability and the accuracy is within ±0.5 μm.

[0099] Example 7: This example aims to print microlens arrays with different microlens gaps (gap is the distance between two adjacent lenses minus the radius of the two lenses, i.e., the distance between the two lens edges) (8μm, 9μm, 12μm, 48μm, and 85μm) and different microlens morphologies (columnar, square). Preparation was performed as follows.

[0100] A method for preparing a microlens array comprises the following steps:

[0101] S1. Design and manufacture a defining layer according to the size of the microlens array to be printed. The defining layer has grooves corresponding to the microlens units of the microlens array, and the spacing between adjacent grooves is the spacing between adjacent microlenses.

[0102] S2. Using photolithography technology, a pattern of a defining layer is developed on a cleaned glass substrate to obtain a glass substrate for 3D printing. The defining layer uses LTC 9305 from the LTC9000 series of FUJIFILM Corporation, and the thickness of the defining layer is 1.25 microns.

[0103] S3. Prepare the microlens adhesive material, load it into a 3mL cartridge, install it on the 3D printing platform, and attach the printing needle. The adhesive material is an acrylic ester UV adhesive, containing approximately 50% acrylic resin, approximately 48% acrylate monomer, approximately 1% photoinitiator, and approximately 1% rheological additive.

[0104] Obtaining printing parameters of the microlens array including microlens height, microlens width, and microlens spacing;

[0105] The visual device of the 3D printing equipment is used to grasp and position the edge of the glass substrate, and the precision motion platform is used to ensure that the needle is aligned with the middle of the limiting layer, and the material is printed within the limiting layer;

[0106] The microlens array is printed and cured according to the printing parameter settings; a microlens array is obtained, and the microscope images are shown in Figures 7A to 7E, wherein Figure 7A shows a microlens array with an 8 μm gap, Figure 7B shows a microlens array with a 9 μm gap, Figure 7C shows a microlens array with a 12 μm gap, Figure 7D shows a microlens array with a 48 μm gap, and Figure 7E shows a microlens array with an 85 μm gap.

[0107] Comparative Example 1

[0108] The difference from Example 1 is that no limiting layer is provided, and the microlens array is directly printed on the glass substrate.

[0109] The actual microlens pitch is 172.5 μm, the microlens width is 146.2 μm, and the microlens height is 31.3 μm.

[0110] In this comparative example, no limiting layer is provided, and the edge morphology of the microlens obtained is not neat, the overall width accuracy and the microlens repeating spacing are both greater than 5 μm, and in particular, the lens height cannot be controlled.

[0111] Comparative Example 2

[0112] The difference from Example 1 is that the material of the limiting layer is black photoresist for negative LCD flat panel display.

[0113] The actual pitch of the microlenses obtained is 175.5 μm, the width of the microlenses is 148.2 μm, and the height of the microlenses is 35.6 μm. The surface morphology of the obtained microlenses is shown in FIG8 .

[0114] The microlenses obtained by using the limiting layer of this comparative example have an accuracy exceeding 5 microns compared to the design value. In addition, the edges of the microlenses obtained are uneven, with some edge materials clearly exceeding the limiting layer, and the linear shape of the cylindrical lenses is uneven.

Claims

1. A method for preparing a controllable morphology microlens array, characterized in that: The steps include: S1. According to the microlens array to be printed, a defining layer having a pattern consistent with the microlens array is formed on the substrate; S2. Printing the microlens array on the substrate using a microlens glue material; S3. Curing the microlens array to obtain a finished microlens array.

2. The preparation method according to claim 1, characterized in that The limiting layer forms a groove on the substrate that is consistent with the microlens array. There is a first mutually repulsive force between the material of the limiting layer and the microlens glue material. The microlens array is obtained based on the first force and the position of the groove.

3. The preparation method according to claim 2, characterized in that The first force includes one or more of intermolecular force, magnetic force or electrostatic force.

4. The preparation method according to claim 1, characterized in that The main component of the material of the limiting layer is polyimide, and the material of the microlens array is acrylic resin.

5. The preparation method according to claim 4, characterized in that The limiting layer is polyimide photoresist, which is formed on the substrate by photolithography.

6. The preparation method according to claim 1 or 2, characterized in that: The thickness of the limiting layer is 0.5 μm to 15 μm.

7. The preparation method according to claim 1 or 2, characterized in that: The thickness of the limiting layer is 0.5 μm to 5 μm.

8. The preparation method according to claim 1, characterized in that The step S2 further comprises: Acquiring printing parameters of the microlens array; Positioning the edge of the substrate by using a visual device; According to the printing parameters, a printing mode is set to print the microlens array once or multiple times, The printing parameters include microlens height, microlens width and microlens spacing.

9. The preparation method according to claim 1, characterized in that The printing method is ink direct writing printing or electrohydrodynamic inkjet printing, inkjet printing or piezoelectric printing.

10. A microlens array, obtained by the preparation method according to any one of claims 1 to 9.

11. A 3D printing device for implementing the microlens array prepared by the method according to any one of claims 1 to 9.

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