阅读说明：本技术 一种3d人工复眼及其制备方法 (3D artificial compound eye and preparation method thereof ) 是由 吴欣学 方朝龙 于 2020-07-28 设计创作，主要内容包括：本发明提供一种3D人工复眼制备方法,包括获取刚性平面微透镜阵列模具,其上表面形成有多个盲孔；将聚二甲基硅氧烷及其交联剂以一定的重量比混合,并将混合物液体旋涂在模具的上表面上；将混合物进行烘烤固化,形成为具有一定粘性的凸面微透镜阵列膜；利用聚二甲基硅氧烷制作而成的柔性半球挤压凸面微透镜阵列膜并烘烤,直至凸面微透镜阵列膜完全覆盖于柔性半球的外表面且粘在一起,并脱离模具的上表面；撤除柔性半球的挤压,柔性半球恢复形状,凸面微透镜阵列膜被柔性半球向外被顶起,形成球面轮廓的微透镜阵列结构即为3D人工复眼。实施本发明,不仅工艺简单、成本低且变化灵活,还能有高质量的光洁度,实现无失真成像和宽视野。(The invention provides a preparation method of a 3D artificial compound eye, which comprises the steps of obtaining a rigid plane micro-lens array mould, wherein a plurality of blind holes are formed on the upper surface of the rigid plane micro-lens array mould; mixing polydimethylsiloxane and a cross-linking agent thereof according to a certain weight ratio, and spin-coating the mixture liquid on the upper surface of a mould; baking and curing the mixture to form a convex microlens array film with certain viscosity; extruding and baking the convex micro-lens array film by using a flexible hemisphere made of polydimethylsiloxane until the convex micro-lens array film completely covers the outer surface of the flexible hemisphere and is adhered together, and separating from the upper surface of the die; the extrusion of the flexible hemisphere is removed, the flexible hemisphere restores the shape, the convex micro-lens array film is jacked up outwards by the flexible hemisphere, and the micro-lens array structure with the spherical contour is the 3D artificial compound eye. The invention has the advantages of simple process, low cost, flexible change, high-quality smoothness, and realization of distortion-free imaging and wide visual field.)

1. A method for preparing a 3D artificial compound eye, the method comprising the steps of:

obtaining a rigid planar microlens array mold, wherein a plurality of blind holes formed by downwards sinking are formed on the upper surface of the rigid planar microlens array mold;

mixing polydimethylsiloxane and a cross-linking agent thereof according to a certain weight ratio, and spin-coating the obtained mixture on the upper surface of the rigid planar microlens array mold;

baking and curing the mixture on the upper surface of the rigid plane microlens array mould to form a convex microlens array film with certain viscosity;

extruding and baking the convex micro-lens array film by using a flexible hemisphere made of polydimethylsiloxane until the convex micro-lens array film is completely adhered to the outer surface of the flexible hemisphere and separated from the upper surface of the rigid planar micro-lens array mold;

and removing the extrusion on the flexible hemisphere, and making the convex micro-lens array film bulge outwards to form a hemisphere and separate from the outer surface of the flexible hemisphere by using the restoring force of the flexible hemisphere, namely the prepared 3D artificial compound eye.

2. The method of claim 1, wherein the plurality of blind holes have the same structure and are arranged in a uniform and ordered array structure.

3. The method for preparing a 3D artificial compound eye according to claim 1, wherein the steps of mixing polydimethylsiloxane and a cross-linking agent thereof in a certain weight ratio and spin-coating the resulting mixture on the upper surface of the rigid planar microlens array mold are specifically:

mixing polydimethylsiloxane and a cross-linking agent thereof in a ratio of 10: 1 and spin-coating the resulting mixture on the upper surface of the rigid planar microlens array mold at a speed of 2000 r/min for 1 minute.

4. The method for preparing a 3D artificial compound eye according to claim 1, wherein the step of baking and curing the mixture on the upper surface of the rigid planar microlens array mold comprises:

the mixture on the upper surface of the rigid planar microlens array mold was cured after baking at 80 ℃ for 5 minutes.

5. The method for preparing a 3D artificial compound eye according to claim 1, wherein the step of pressing the convex microlens array film with a flexible hemisphere made of polydimethylsiloxane and baking until the convex microlens array film is completely adhered to the outer surface of the flexible hemisphere and separated from the upper surface of the rigid planar microlens array mold comprises:

adopt 14 newton power extrusion on the flexible hemisphere the convex surface microlens array membrane makes the convex surface microlens array membrane cover completely the surface of flexible hemisphere to toast 5 minutes back under 80 ℃, make the convex surface microlens array membrane glues in the surface of flexible hemisphere, and break away from the upper surface of rigid plane microlens array mould.

6. The method for preparing a 3D artificial compound eye according to claim 1, wherein the 3D artificial compound eye has a field angle of 145.7 °.

7. The method of preparing a 3D artificial compound eye according to claim 1, further comprising:

and detecting the 3D artificial compound eye by using a scanning electron microscope and a laser scanning confocal microscope.

8. The method of preparing a 3D artificial compound eye according to claim 1, further comprising:

and preparing the rigid planar microlens array mold through a thermal reflow process.

9. A 3D artificial compound eye, characterized in that it is prepared by the method for preparing a 3D artificial compound eye according to any one of claims 1 to 8.

Technical Field

The invention relates to the technical field of 3D, in particular to a 3D artificial compound eye and a preparation method thereof.

Background

Insects such as moths, beetles and crickets have compound eyes. The compound eye is composed of thousands of micro-sized small eyes and arranged on a spherical eye with a size of millimeter order, so that the compound eye has various excellent characteristics and functions, such as wide visual field, high-sensitivity detection and rapid motion tracking. Therefore, more and more researchers are trying to imitate the function of compound eyes for applications in a wide range of fields, such as wide-angle detection systems, endoscopes, digital cameras, and auto-driving of automobiles.

Various methods have been proposed for the preparation of artificial compound eyes, including in particular a liquid dielectrophoresis-driven preparation method, a direct inkjet printing preparation method, a thermal reflow preparation method, a laser-induced polymer swelling preparation method, a surface energy-driven hydrodynamic preparation method, and a thermal embossing preparation method, which, although flexible preparation of 2D planar microlens arrays (MLAs) is possible, are difficult to use for the manufacture of 3D curved compound eyes.

Recently, the fabrication of 3D artificial compound eyes using sophisticated techniques has begun, including laser ablation assisted dry or wet etch fabrication methods, layered reflow fabrication methods, externally driven deformation fabrication methods for 2D planar MLA films, and other biologically inspired technical fabrication methods. The laser ablation assisted dry or wet etching preparation method is used for preparing the silicon dioxide 3D artificial compound eye which can work under the conditions of high temperature and high pressure, but the cost is high and the preparation process is complex; the geometric form of the micro lens can be flexibly adjusted by the layered reflux preparation method, but due to the technical limitation, the visual field can be limited to about 90 degrees unless a complex method is adopted; the preparation method of deforming 2D planar MLA films into spherical surfaces using an external actuator is a good method of preparing 3D artificial compound eyes with a wide and adjustable field of view, but the 2D film must be detached from its main mold before the deformation process, which may contaminate or destroy the film.

Therefore, a method for preparing a 3D artificial compound eye is needed, which has the advantages of simple process, low cost, flexible change, high-quality smoothness, distortion-free imaging and wide visual field.

Disclosure of Invention

The technical problem to be solved by the embodiments of the present invention is to provide a 3D artificial compound eye and a method for preparing the same, which not only have simple process, low cost and flexible variation, but also have high-quality smooth finish, and realize distortion-free imaging and wide field of view.

In order to solve the technical problem, an embodiment of the present invention provides a method for preparing a 3D artificial compound eye, including the following steps:

obtaining a rigid planar microlens array mold, wherein a plurality of blind holes formed by downwards sinking are formed on the upper surface of the rigid planar microlens array mold;

mixing polydimethylsiloxane and a cross-linking agent thereof according to a certain weight ratio, and spin-coating the obtained mixture on the upper surface of the rigid planar microlens array mold;

baking and curing the mixture on the upper surface of the rigid plane microlens array mould to form a convex microlens array film with certain viscosity;

extruding and baking the convex micro-lens array film by using a flexible hemisphere made of polydimethylsiloxane until the convex micro-lens array film completely covers the outer surface of the flexible hemisphere and is adhered together, and separating from the upper surface of the rigid planar micro-lens array die;

and removing the extrusion on the flexible hemisphere, and gradually making the convex micro-lens array film bulge outwards to form a spherical crown shape by utilizing the restoring force of the flexible hemisphere and break away from the outer surface of the flexible hemisphere, namely the prepared 3D artificial compound eye.

The blind holes are all of the same structure and are arranged according to a uniform and ordered array structure.

The method comprises the following steps of mixing polydimethylsiloxane and a cross-linking agent thereof according to a certain weight ratio, and spin-coating the obtained mixture on the upper surface of the rigid planar microlens array mold, wherein the steps comprise:

mixing polydimethylsiloxane and a cross-linking agent thereof in a ratio of 10: 1 and spin-coating the resulting mixture on the upper surface of the rigid planar microlens array mold at a speed of 2000 r/min for 1 minute.

The step of baking and curing the mixture on the upper surface of the rigid planar microlens array mold specifically comprises the following steps:

the mixture on the upper surface of the rigid planar microlens array mold was cured after baking at 80 ℃ for 5 minutes.

Wherein, utilize the flexible hemisphere extrusion that utilizes the preparation of polydimethylsiloxane to form convex surface microlens array membrane and toast, until convex surface microlens array membrane covers completely the surface of flexible hemisphere and glue together, and break away from the step of the upper surface of rigid plane microlens array mould specifically is:

adopt 14 newton power extrusion on the flexible hemisphere the convex surface microlens array membrane makes the convex surface microlens array membrane cover completely the surface of flexible hemisphere to toast 5 minutes back under 80 ℃, make the convex surface microlens array membrane glues in the surface of flexible hemisphere, and break away from the upper surface of rigid plane microlens array mould.

Wherein the 3D artificial compound eye has a field angle of 145.7 degrees.

Wherein the method further comprises:

and detecting the 3D artificial compound eye by using a scanning electron microscope and a laser scanning confocal microscope.

Wherein the method further comprises:

and preparing the rigid planar microlens array mold through a thermal reflow process.

The embodiment of the invention also provides a 3D artificial compound eye which is prepared by adopting the preparation method of the 3D artificial compound eye.

The embodiment of the invention has the following beneficial effects:

the invention utilizes the principle that when an elastic ball (such as a flexible hemisphere) is extruded on a rough surface (such as a convex micro-lens array film), particles on the rough surface can be easily transferred to the surface of the elastic ball after external pressure is usually removed, and the 3D artificial compound eye is prepared.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is within the scope of the present invention for those skilled in the art to obtain other drawings based on the drawings without inventive exercise.

Fig. 1 is a flowchart of a method for preparing a 3D artificial compound eye according to an embodiment of the present invention;

fig. 2 is a scanning electron microscope image of an artificial compound eye prepared under a pressure of 14N in an application scenario of the method for preparing a 3D artificial compound eye according to the embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.

As shown in fig. 1, a method for preparing a 3D artificial compound eye according to a first embodiment of the present invention includes the following steps:

step S1, obtaining a rigid plane micro-lens array mould, wherein a plurality of blind holes formed by sinking downwards are formed on the upper surface of the rigid plane micro-lens array mould;

step S2, mixing dimethyl silicone polymer and cross linker thereof according to a certain weight ratio, and spin-coating the obtained mixture on the upper surface of the rigid plane micro lens array mould;

step S3, baking and curing the mixture on the upper surface of the rigid plane microlens array mould to form a convex microlens array film with certain viscosity;

step S4, extruding and baking the convex micro-lens array film by using a flexible hemisphere made of polydimethylsiloxane until the convex micro-lens array film completely covers the outer surface of the flexible hemisphere and is adhered together, and separating from the upper surface of the rigid planar micro-lens array mold;

and S5, removing the extrusion of the flexible hemisphere, and making the convex micro-lens array film gradually shrink inwards into a hemispherical shape by using the restoring force of the flexible hemisphere and separate from the outer surface of the flexible hemisphere, namely the prepared 3D artificial compound eye.

In step S1, preparing a rigid planar microlens array mold by a thermal reflow process, such that a plurality of blind holes recessed downward are formed on an upper surface of the rigid planar microlens array mold; the blind holes are all of the same structure and are arranged according to a certain array structure. It should be noted that the blind holes may be of different configurations; the arrangement of the blind holes is not limited to the array structure.

In step S2, the polydimethylsiloxane and its cross-linking agent (e.g., curing agent, hardener) are mixed in a ratio of 10: 1 by weight ratio and spin-coating the resulting mixture on the upper surface of a rigid planar microlens array mold at a speed of 2000 r/min for 1 minute. It should be noted that the weight ratio, the spin coating speed and the time can be adjusted according to actual requirements.

In step S3, the mixture on the upper surface of the rigid planar microlens array mold is baked at 80 ℃ for 5 minutes and then cured to form a convex microlens array film having a certain viscosity.

In step S4, the convex microlens array film is pressed by 14 newtons force on the flexible hemisphere made of polydimethylsiloxane, so that the convex microlens array film completely covers the outer surface of the flexible hemisphere, and after baking at 80 ℃ for 5 minutes, the convex microlens array film is adhered to the outer surface of the flexible hemisphere and separated from the upper surface of the rigid planar microlens array mold. It should be noted that in order to increase the adhesion between the convex microlens array film and the flexible hemisphere, the flexible hemisphere should have a certain adhesion optimum.

In step S5, the 3D artificial compound eye is obtained by removing the pressing of the flexible hemisphere and using the restoring force of the flexible hemisphere to make the convex microlens array film gradually bulge outward into a spherical crown shape and separate from the outer surface of the flexible hemisphere, based on the principle that when the elastic sphere is pressed against a rough surface, the particles on the rough surface are easily transferred to the surface of the elastic sphere, usually after the external pressure is removed. At this time, the field angle of the 3D artificial compound eye was 145.7 °.

In the first embodiment of the present invention, the method further includes:

the scanning electron microscope and the laser scanning confocal microscope are used for detecting the 3D artificial compound eye, so that the prepared 3D artificial compound eye has a large number of uniformly distributed small eyes and high-quality smooth finish.

As shown in fig. 2, an application scenario of the 3D artificial compound eye preparation method in the first embodiment of the present invention is further described:

the ommatidium is a unit for forming the compound eye, and therefore is the key point for realizing clear and undistorted imaging of the 3D artificial compound eye. The effect of convex membrane bending deformation on surface finish and small eye morphology was studied using Scanning Electron Microscopy (SEM) and Laser Scanning Confocal Microscopy (LSCM).

Fig. 2 (a) - (c) show SEM images of artificial compound eyes prepared under a pressure of 14N. The window shows a curved microlens array MLA that is uniformly covered on a polydimethylsiloxane PDMS dome without any dust particles. The high surface cleanliness is attributed to the high efficiency process which reduces the number of steps in the manufacturing process, thereby reducing the possibility of dust particle contamination. Fig. 2 (c) shows an enlarged SEM image of the ommatidium formed on the curved surface. These eyes exhibit a spherical morphology with a high surface finish. This means that the fabrication method can replicate the surface finish of the 2D MLA master mold. Using LSCM, the width of the ommatidia and the gap between them were found to be 20.8 and 4.4 mm, respectively. In contrast, in the prepared 2D plano-convex MLA, the width and gap measurements of the microlenses were 20.6 and 4.25 mm, respectively.

This is because the area of the film increases as it changes from a flat to a curved surface, increasing the width of the ommatidium and the gap between them. Although the adhesive film was spherical, the cross-sectional widths of the ommatidium in the x and y directions remained equal in the prepared 3D compound eye. At this time, the width difference of 50 ommatidium selected from different regions of the 3D artificial compound eye is only 0.5%. In addition, the height and gap measurements of the ommatidium also showed good consistency. These results demonstrate the high efficiency of the method for preparing 3D artificial compound eyes with good homogeneity.

To obtain reliable results, the height, width and gap of the formed ommatidium at 2N and 6N pressures were also measured. SEM images of 3D artificial compound eyes formed under 2N, 6N and 14N pressures are shown in fig. 2 (a), (b), (c). Various forms of small eyes can be found in these images. It is noteworthy that the efficient manufacturing process can transfer a variety of micro-or nanoparticles on a curved surface (including of course MLA) at 100% bulk density. More importantly, there was no significant difference in the ommatidium morphology and the gap between batch-prepared 3D artificial compound eyes, indicating that the preparation method is feasible for mass production of 3D artificial compound eyes.

An important feature of 3D artificial compound eyes is the field of view (FOV-field angle of view), which is closely related to the width and height of the compound eye. The theoretical value of the FOV can be expressed as:

FOV = 2arcsin4η/ 1+4η²

where η is the aspect ratio of the artificial compound eye. The height to width ratio of the compound eye increases as the pressure increases to F = 14N, and remains constant thereafter. According to the above equation, the FOV is increasing as the aspect ratio ranges from 0 to 0.5. Therefore, it was concluded that the artificial compound eye has the maximum theoretical FOV value of 145.7 ° at F = 14N, and wide-area imaging is possible.

The optical imaging function of the 3D artificial compound eye is a key factor for checking whether the preparation method is effective or not. A black plastic sheet with the transparent letter "A" was placed over the white light LED light source of the optical microscope, and the images formed by the different areas of the compound eye were viewed clearly with a charge coupled device camera. The image formed at the edges of the photograph becomes blurred or even distorted. This is due to the non-planar distribution of the microlenses, which means that a sharply focused image can only be located in a small area of the sphere. As the compound eye moves upward, the core area in the ccd camera will blur and form a wider sharp "a" image field. By adjusting the objective lens from far to near, clear foci can be clearly observed, and these clear images and clear foci again indicate that the microlenses on the PDMS hemisphere have higher uniformity and excellent morphology, which indicates that the efficient fabrication method does not greatly affect the morphology of the microlenses even if the convex MLA film is deformed during the fabrication process.

Corresponding to the method for preparing a 3D artificial compound eye in the first embodiment of the present invention, a second embodiment of the present invention further provides a 3D artificial compound eye, which is prepared by the method for preparing a 3D artificial compound eye in the first embodiment of the present invention.

The embodiment of the invention has the following beneficial effects:

the invention utilizes the principle that when an elastic ball (such as a flexible hemisphere) is extruded on a rough surface (such as a convex micro-lens array film), particles on the rough surface can be easily transferred to the surface of the elastic ball after external pressure is usually removed, and the 3D artificial compound eye is prepared.

It will be understood by those skilled in the art that all or part of the steps in the method for implementing the above embodiments may be implemented by relevant hardware instructed by a program, and the program may be stored in a computer-readable storage medium, such as ROM/RAM, magnetic disk, optical disk, etc.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention, and it is therefore to be understood that the invention is not limited by the scope of the appended claims.