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

Abstract

The application belongs to the technical field of 3D printing equipment, and relates to a preparation method of controllable-morphology microlens array, a microlens array, application and 3D printing equipment, the preparation method comprises the following steps: S1. According to the microlens array to be printed, a limiting layer with a pattern consistent with the microlens array is formed on a substrate; S2. The microlens array is printed on the substrate using a microlens glue solution material; S3. The microlens array is solidified to obtain a microlens array finished product. The preparation method of the microlens array provided by the application is simple to operate, can design limiting layers with different patterns according to the morphology of different microlens arrays, meets the preparation of different microlens arrays, and can adapt to the preparation of array microlenses on various substrates. The obtained microlens array is more accurate in shape and size, and the precision can reach within 0.5 microns.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of optical instrument manufacturing, and relates to a preparation method of an array microlens, in particular to a preparation method of a controllable topography microlens array, a microlens array, application and a 3D printing device. BACKGROUND

[0002] A microlens array is formed by a series of array elements with diameters ranging from microns to millimeters arranged in a certain rule. In a small size area, a large number of optical functions can be realized. By adjusting the shape, curvature and spacing of the lens, different optical effects such as focusing, magnification, transformation and segmentation can be achieved. Moreover, it has high optical efficiency and low loss, which can improve the performance of optical systems. Therefore, the application of microlens array is very wide. In the imaging field, it can be used to realize high-resolution image acquisition, optical microscopy and spectral imaging, etc. In optical communication, microlens array can be used for beam shaping, optical path alignment and optical coupling, etc. In the field of optical sensing, it can be used to realize micro-sensors and fiber-optic sensors, etc. In addition, microlens array can also be applied to optical display, laser processing and biomedicine, etc.

[0003] At present, the main methods for making spherical microlenses are mechanical processing, hot reflow and glue spraying. The mechanical processing method is to obtain a mold through precise mechanical processing, and then form an array microlens structure through injection molding or nano-imprinting, etc. This method requires high precision of the mold topography, and there may be precision problems in actual demolding or imprinting. The hot reflow method is to expose photoresist to light to form a cylindrical or array column topography, and then heat it to make the photoresist soften in a glass state, so that it spontaneously forms a microlens topography under the action of surface tension. However, due to the strong flowability of photoresist at high temperature, the microlens topography varies greatly at different positions due to the influence of environment and heating uniformity, and the overall uniformity is poor. The glue spraying method is to form liquid droplets on the surface of the substrate through a precise nozzle and a precise position control platform, and then form a microlens topography. This method is efficient and easy to operate, but it has the disadvantage of requiring strong adaptation of materials and substrates to form stable and adhesive microlens structures.

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

[0005] CN107009613A discloses a microlens array manufacturing method based on three-dimensional direct writing. A three-dimensional direct writing device is used to sequentially directly write a microlens precursor array at a predetermined array position perpendicular to the surface of a transparent substrate, and then a hot melting process is performed on the microlens precursor array to form a microlens array relying on surface tension. This method solves the problems of lens surface steps and internal interface layers existing in three-dimensional printing.

[0006] With the expansion of the application range of microlens array to the precision direction, the precision requirement of microlens array in the prior art is continuously improved. The manufacturing method directly bonds the liquid solution and the surface of the transparent substrate by applying pressure, and then prints, which has poor position control precision of the microlens precursor, and the precision needs to be further improved. Moreover, the material and the substrate need to be well adapted to form a stable microlens array with certain adhesion.

[0007] For this, in the prior art, positioning grooves are arranged on the substrate to accurately print the microlens. Referring to CN108732661A, first, a black hole groove array (i.e., a hole array) is prepared by using a photolithography method, and the black hole is used for positioning; then, a low-viscosity high-transmittance UV resin is used as ink to perform inkjet printing on the cleaned black hole array. However, in actual operation, the degree of improvement of the precision is limited, and further improvement of the precision depends on the precision of the printing equipment. SUMMARY

[0008] The purpose of the present application is to solve the precision problem existing in the preparation process of the microlens array at present, and to provide a preparation method of controllable topography microlens array.

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

[0010] A preparation method of controllable topography microlens array, comprising the following steps:

[0011] S1. Forming a limiting layer with a pattern consistent with the microlens array on the substrate according to the microlens array to be printed;

[0012] S2. Printing the microlens array on the substrate using microlens glue solution material;

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

[0014] As a preferred embodiment of the above technical solution, the limiting layer forms a groove consistent with the microlens array on the substrate, and the material of the limiting layer and the microlens glue solution material have a first action force of mutual repulsion. Based on the first action force and the groove position, the microlens array is obtained.

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

[0016] In the scheme of the present application, a limiting layer is formed on the substrate, the pattern of the limiting layer is designed according to the microlens array, and a groove array is formed at the position corresponding to the microlens. The microlens array is printed on the limiting layer. The groove can position the printing of the microlens on the one hand, and on the other hand, the groove can limit the glue material of the microlens, so that the shape and size of the printed microlens are more accurate, especially the height of the microlens can be accurately controlled.

[0017] The above scheme guarantees high accuracy, and also depends on the accuracy of the printing equipment. Under the condition of the accuracy of the existing printing equipment in the prior art, the highest accuracy can only reach 5 microns.

[0018] The above technical scheme further selects the material of the limiting layer to form a certain force between the limiting layer and the glue material of the microlens, such as intermolecular force or magnetic force or electrostatic force. By selecting the material and using the force between the limiting layer and the glue material of the microlens, the precise positioning of the glue material of the microlens in the groove can be assisted to achieve high printing accuracy. Even if the printing head of the printing equipment is offset, the position of the microlens can still be accurately positioned, and the glue material can be printed in the groove of the limiting layer. The accuracy can reach within 0.5 microns.

[0019] The above technical scheme can also effectively control the height of the microlens by setting the limiting layer and further selecting the material of the limiting layer. Since the printing uses glue material, the control of the height of the microlens is a difficulty in the process of 3D printing microlens. By setting the limiting layer, the width of the microlens can be limited in the horizontal direction, and the control accuracy of the height can be improved by the force between the limiting layer material and the glue material of the microlens. It is more conducive to the precision control of the size of the microlens.

[0020] As a preferred embodiment of the above technical scheme, 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 scheme, the limiting layer is a polyimide photoresist formed on the substrate by photolithography.

[0022] Polyimide photoresist is a high-performance photoresist material with many advantages. Including but not limited to the following advantages, high resolution: polyimide photoresist has excellent resolution, which can realize the preparation of microstructure. It can realize sub-micron level pattern definition, which is suitable for manufacturing high-density integrated circuits and other micro-nano devices. High sensitivity: polyimide photoresist has high sensitivity to ultraviolet light, which can speed up the photoetching process and improve production efficiency. It can form a pattern in a shorter exposure time, saving manufacturing time and cost. Good chemical stability: polyimide photoresist has good chemical stability and can be used in various manufacturing environments while providing reliable pattern definition.

[0023] In the present application, polyimide photoresist is selected to exert its own advantages to manufacture a limiting layer more conducive to the morphology and size of the microlens.

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

[0025] As a preferred embodiment of the above technical solution, the thickness of the limiting layer is 0.5-15 microns. In the printing process of the array microlens, the thickness of the limiting layer also has an important influence on the size accuracy of the microlens. When the thickness of the limiting layer is less than 0.5 microns, it is difficult to maintain the morphology and size of the microlens array, and the control accuracy is poor for the microlens pitch and height. When the thickness of the limiting layer is greater than 15 microns, the too high limiting layer is not conducive to the control of the microlens height.

[0026] In the printing process of the array microlens, in order to better control the morphology and size of the microlens array and widen the regulation range of the microlens height, the thickness of the limiting layer is preferably set between 0.5 microns and 5 microns.

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

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

[0029] Obtaining the printing parameters of the microlens array;

[0030] Positioning the substrate edge by a visual device and positioning the substrate edge;

[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 application further provides a microlens array prepared by the preparation method.

[0034] By implementing the technical scheme, the application forms a limiting layer on the substrate, positions the printing of the microlens by the limiting layer, and limits the glue liquid material of the microlens, so that the shape and size of the printed microlens are more accurate.

[0035] Furthermore, the application can further improve the printing accuracy by selecting the limiting layer material, so that the highest accuracy is not greater than 0.5 microns even under the condition of lacking printing equipment accuracy.

[0036] The application further provides the application of the microlens array, which is applied to naked-eye 3D, display device anti-peeping, etc.

[0037] The application further provides a preparation device for implementing the preparation method of the microlens array.

[0038] The preparation method of the microlens array is simple to operate, can design different limiting layers according to the topography of different microlens arrays, meet the preparation of different microlens arrays, and can adapt to the preparation of array microlenses of various substrates. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 Flow chart for preparing a microlens array by the preparation method described in Example 1.

[0040] Figure 2 Microlens unit prepared by the preparation method described in Example 1.

[0041] Figure 3 Microlens unit prepared by the preparation method described in Example 2.

[0042] Figure 4 Microlens unit prepared by the preparation method described in Example 3.

[0043] Figure 5 Flow chart for preparing a microlens array by the preparation method described in Example 4.

[0044] Figures 6A-6F The microlens array prepared by the preparation method described in Example 1 is used as a microlens array with a height of 44.5 μm.

[0045] Figures 7A-7E The partial electron microscope image of the microlens array prepared by the preparation method described in Example 7.

[0046] Figure 8 The partial electron microscope image of the microlens array prepared by the preparation method described in Comparative Example 2.

[0047] In the figure, 1 is a substrate, 2 is a limiting layer, 3 is a microlens array, and 4 is a printing needle. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0049] Example 1

[0050] This embodiment aims to print a microlens array with a pitch (the distance between the centers of two adjacent lenses) of 181.8 μm, a width of 133.5 μm, and a height of 44.5 μm. The preparation is carried out according to the following method.

[0051] A preparation method of a microlens array, comprising the following steps:

[0052] S1. Design and manufacture a limiting layer according to the size of the microlens array to be printed, the limiting layer having grooves consistent with the microlenses of the microlens array, and the pitch between adjacent grooves being the pitch of adjacent microlenses.

[0053] S2. Develop the pattern of the limiting layer on a cleaned glass substrate by a photolithography technology, thereby obtaining a glass substrate for 3D printing; the limiting layer is LTC 9305 of the LTC9000 series of FUJIFILM Company, and the thickness of the limiting layer is 0.5 microns.

[0054] S3. Configure the glue solution material of the microlens, load it into a 3 mL cartridge, and install it on the platform of the 3D printing equipment and add a printing needle; the glue solution material is an acrylate UV glue, wherein the content of acrylic resin is about 50%, the content of acrylate monomer is about 48%, the content of photoinitiator is about 1%, and the content of rheological aid is about 1%.

[0055] Obtain the printing parameters of the microlens array, including microlens height, microlens width, and microlens spacing;

[0056] The 3D printing equipment uses a vision device to grip and position the glass substrate, and a precision motion platform ensures the needle is aligned with the center of the defined layer, printing the material within that layer. Figure 1 As shown;

[0057] The microlens array is printed and cured according to the printing parameters set.

[0058] See the scanning electron microscope image of the obtained microlens array. Figure 2 The actual microlens array has a microlens spacing of 181.8 μm, a microlens width of 133.5 μm, and a microlens height of 44.7 μm.

[0059] Example 2

[0060] This embodiment aims to print a microlens array with a microlens spacing of 181.8 μm, a microlens width of 88.5 μm, and a microlens height of 16.0 μm. It is fabricated according to the following method.

[0061] A method for fabricating a microlens array includes the following steps:

[0062] S1. By designing and fabricating a patterned limiting layer, the limiting layer has grooves corresponding to the microlens units of the microlens array, and the spacing between adjacent grooves is the spacing between adjacent microlenses.

[0063] S2. Using photolithography, a defined layer pattern is developed on a cleaned glass substrate to obtain a glass substrate for 3D printing; the defined layer uses FUJIFILM's LTC9000 series LTC 9320, and the thickness of the defined layer is 1.25 micrometers.

[0064] S3. Prepare the adhesive material for the microlens, put it into a 3mL container, and install it on the 3D printing equipment platform, and attach the printing needle; the adhesive material is an acrylic UV adhesive, in which the acrylic resin content is about 50%, the acrylic monomer content is about 48%, the photoinitiator content is about 1%, and the rheology modifier content is about 1%;

[0065] Obtain the printing parameters of the microlens array, including microlens height, microlens width, and microlens spacing;

[0066] The glass substrate is positioned by gripping the edge using the vision device of the 3D printing equipment, and the needle is aligned with the middle of the defined layer by the precision motion platform, so that the material is printed in the defined layer.

[0067] According to the printing parameter, the microlens array is printed and solidified in a printing mode; a scanning electron microscope image of the obtained microlens array is shown in Figure 3 The pitch of the microlenses is 181.8 pm, the width of the microlenses is 88.5 pm, and the height of the microlenses is 16.3 pm.

[0068] Example 3

[0069] This example aims to print a microlens array with a pitch of 181.8 pm, a width of 88.5 pm, and a height of 16.0 pm. The preparation is carried out according to the following method.

[0070] A method for preparing a microlens array, comprising the following steps:

[0071] S1. A patterned limiting layer is designed and prepared, and the limiting layer has grooves corresponding to the microlens units of the microlens array.

[0072] S2. A limiting layer pattern is developed on a cleaned glass substrate by a photolithography technology, so as to obtain a glass substrate for 3D printing; FUJIFILM LTC9000 series LTC 9320. The thickness of the limiting layer is 12 microns.

[0073] S3. The glue solution material of the microlens is configured, loaded into a 3 mL cartridge, and installed on the platform of the 3D printing equipment, and a printing needle is added; the glue solution material is an acrylate UV glue, wherein the content of acrylic resin is about 50%, the content of acrylate monomer is about 48%, the content of photoinitiator is about 1%, and the content of rheological aid is about 1%;

[0074] Obtaining the printing parameters of the microlens array, including the height of the microlens, the width of the microlens, and the pitch of the microlens;

[0075] The glass substrate is positioned by the visual device of the 3D printing equipment, and the needle is aligned to the middle of the limiting layer by the precise motion platform, so as to print the material in the limiting layer;

[0076] According to the printing parameter, the microlens array is printed and solidified in a printing mode; a scanning electron microscope image of the obtained microlens array is shown in Figure 4 The pitch of the microlenses is 181.8 pm, the width of the microlenses is 88.5 pm, and the height of the microlenses is 16.2 pm.

[0077] Example 4

[0078] The difference from Example 1 is that in step S5, the needle is intentionally deviated from one side of the limiting layer by 30 pm by the precise motion platform, and the material is printed in the limiting layer, as shown in Figure 5 .

[0079] The actual micro-lens array has a micro-lens pitch of 181.8 μm, a micro-lens width of 133.2 μm, and a micro-lens height of 26 μm.

[0080] As can be seen from the test data of the present embodiment, even if the printing device has poor precision, the micro-lens array with excellent precision can be obtained under the action of the preparation method of the present embodiment, and the present preparation method can compensate for the lack of printing device precision.

[0081] Embodiment 5

[0082] The present embodiment aims to print a micro-lens array with a micro-lens pitch of 181.8 μm, a micro-lens width of 133.5 μm, and a series of micro-lens heights. The preparation is carried out according to the following method.

[0083] A preparation method of a micro-lens array, comprising the following steps:

[0084] S1. Design and manufacture a limiting layer according to the size of the micro-lens array to be printed, the limiting layer having grooves corresponding to the micro-lens units of the micro-lens array, and the pitch between adjacent grooves being the pitch of adjacent micro-lenses.

[0085] S2. Develop the pattern of the limiting layer on the cleaned glass substrate by photolithography technology, thereby obtaining a glass substrate for 3D printing; the limiting layer is LTC 9305 of the LTC9000 series of FUJIFILM company, and the thickness of the limiting layer is 1.25 microns.

[0086] S3. Configure the glue solution material of the micro-lens, load it into a 3 mL cartridge, and install it on the platform of the 3D printing device and add a printing needle; the glue solution material is an acrylate UV glue, wherein the content of acrylic resin is about 50%, the content of acrylate monomer is about 48%, the content of photoinitiator is about 1%, and the content of rheological aid is about 1%;

[0087] Obtain the printing parameters of the micro-lens array, including the micro-lens height, the micro-lens width, and the micro-lens pitch;

[0088] Position the glass substrate by the vision device of the 3D printing device, and ensure that the needle is aligned to the middle of the limiting layer by the precise motion platform, so as to print the material in the limiting layer;

[0089] Print and cure the micro-lens array according to the printing parameters; the obtained micro-lens array is shown in the scanning electron microscope image Figures 6A-6F The actual values and design values of the micro-lens width and height are shown in Table 1.

[0090] Table 1-Actual values and design values of the micro-lens width and height obtained in the present embodiment

[0091]

[0092] The microlens size data obtained by the present embodiment can show that, by implementing the preparation method of the present embodiment, the height, width and pitch of the obtained microlenses can be controlled within an accuracy of 0.5 μm, and in particular, the height of the microlenses can be effectively controlled by the preparation method.

[0093] Embodiment 6

[0094] The present embodiment 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 microns. The preparation of the microlens array is carried out according to the following method.

[0095] A preparation method of a microlens array, comprising the following steps:

[0096] S1. Design and manufacture a limiting layer according to the size of the microlens array to be printed, the limiting layer having grooves corresponding to the microlens units of the microlens array, and the pitch between adjacent grooves being the pitch of adjacent microlenses.

[0097] S2. Develop the pattern of the limiting layer on the cleaned glass substrate by photolithography technology, thereby obtaining a glass substrate for 3D printing; the limiting layer is LTC 9305 of the LTC9000 series of FUJIFILM company, and the thickness of the limiting layer is 2.0 microns.

[0098] S3. Configure the glue solution material of the microlenses, load it into a 3 mL cartridge, and install it on the platform of the 3D printing equipment and add a printing needle; the glue solution material is an acrylate UV glue, wherein the content of acrylic resin is about 50%, the content of acrylate monomer is about 48%, the content of photoinitiator is about 1%, and the content of rheological aid is about 1%;

[0099] Obtain the printing parameters of the microlens array, including the height of the microlenses, the width of the microlenses and the pitch of the microlenses;

[0100] Position the glass substrate by the vision device of the 3D printing equipment, and ensure that the needle is aligned to the middle of the limiting layer by the precise motion platform, so as to print the material in the limiting layer;

[0101] Print and cure the microlens array according to the printing mode set according to the printing parameters; obtain the microlens array. Perform multi-point testing on the height of the microlenses, and the results are shown in Table 2.

[0102] Table 2 - Height values of microlenses obtained by the present embodiment

[0103]

[0104]

[0105] As can be seen from Table 2, using the preparation method of Example 5, the prepared microlens height has good stability, and the accuracy is within ±0.5 μm.

[0106] Example 7

[0107] This example aims to print microlens arrays with different microlens gaps (gap refers to the distance between the edges of two lenses, i.e., the distance between the edges of two lenses) (8 μm, 9 μm, 12 μm, 48 μm, 85 μm) and different microlens topographies (cylindrical, square). The preparation is carried out according to the following method.

[0108] A method for preparing a microlens array, comprising the following steps:

[0109] S1. Design and manufacture a limiting layer by the size of the microlens array to be printed, the limiting layer having grooves corresponding to the microlens units of the microlens array, and the distance between adjacent grooves being the distance between adjacent microlenses.

[0110] S2. Develop the pattern of the limiting layer on a cleaned glass substrate by photolithography technology, thereby obtaining a glass substrate for 3D printing; the limiting layer is LTC 9305 of the LTC9000 series of FUJIFILM Co., Ltd., and the thickness of the limiting layer is 1.25 microns.

[0111] S3. Configure the glue solution material of the microlens, load it into a 3 mL cartridge, and install it on the platform of the 3D printing equipment and add a printing needle; the glue solution material is an acrylate UV glue, wherein the content of acrylic resin is about 50%, the content of acrylate monomer is about 48%, the content of photoinitiator is about 1%, and the content of rheological aid is about 1%;

[0112] Obtain the printing parameters of the microlens array, including the height of the microlens, the width of the microlens, and the distance between the microlenses;

[0113] Position the glass substrate by the vision device of the 3D printing equipment, and ensure that the needle is aligned to the middle of the limiting layer by the precise motion platform, so as to print the material in the limiting layer;

[0114] Print and cure the microlens array according to the printing mode set by the printing parameters; obtain the microlens array, and the microscope chart is shown in Figures 7A-7E , wherein, Figure 7A a microlens array with a gap of 8 μm, Figure 7B a microlens array with a gap of 9 μm, Figure 7C a microlens array with a gap of 12 μm, Figure 7D a microlens array with a gap of 48 μm, Figure 7E a microlens array with a gap of 85 μm.

[0115] Comparative Example 1

[0116] The difference from Example 1 is that no limiting layer is provided, and the printing of the microlens array is directly performed on the glass substrate.

[0117] The actual obtained microlens has a pitch of 172.5 μm, a width of 146.2 μm, and a height of 31.3 μm.

[0118] The actual obtained microlens has a pitch of 172.5 μm, a width of 146.2 μm, and a height of 31.3 μm.

[0119] Comparative Example 2

[0120] The difference from Example 1 is that the material of the limiting layer is a black photoresist for negative LCD flat panel display.

[0121] The actual obtained microlens has a pitch of 175.5 μm, a width of 148.2 μm, and a height of 35.6 μm. The surface morphology of the obtained microlens is shown in FIG. 6. Figure 8 .

[0122] Using the limiting layer of the comparative example, the actual obtained microlens has a precision exceeding 5 microns compared to the design value. Moreover, the edge of the obtained microlens is not neat, and part of the edge material obviously exceeds the limiting layer, and the cylindrical lens line type is not uniform.

Claims

1. A method for fabricating a controllable morphology microlens array, characterized in that, Includes the following steps: S1. Form a defining layer on a substrate with a pattern consistent with the microlens array to be printed; S2. Print the microlens array on the substrate using a microlens adhesive material; S3. Solidify the microlens array to obtain the finished microlens array; The main component of the defining layer is polyimide, and the material of the microlens array is an acrylate resin. The material of the defining layer and the microlens adhesive material have a first repulsive force, which includes one or more of intermolecular forces, magnetic forces, or electrostatic forces.

2. The preparation method according to claim 1, characterized in that, The defining layer forms a groove on the substrate that corresponds to the microlens array, and the microlens array is obtained based on the first force and the position of the groove.

3. The preparation method according to claim 1, characterized in that, The defining layer is a polyimide photoresist, which is formed on the substrate by photolithography.

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

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

6. The preparation method according to claim 1, characterized in that, Step S2 further includes: Obtain the printing parameters of the microlens array; The substrate is positioned by gripping its edges using a vision device. The printing method can be set according to the printing parameters to print the microlens array once or multiple times. The printing parameters include microlens height, microlens width, and microlens spacing.

7. The preparation method according to claim 1, characterized in that, The printing method is ink direct writing printing, electro-hydraulic inkjet printing, inkjet printing, or piezoelectric printing.

8. A microlens array, obtained by the preparation method according to any one of claims 1-7.

9. A 3D printing apparatus for implementing the fabrication method of any one of claims 1-7 for a microlens array.

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