CN106853546A - Microlens array mold core and manufacturing method thereof, microlens array and manufacturing method thereof - Google Patents

Abstract

The invention discloses a micro-lens array mold core and a manufacturing method thereof, and a micro-lens array and a manufacturing method thereof. The manufacturing method of the micro-lens array mold core comprises the following steps: providing a cylindrical clamp, and coaxially installing the cylindrical clamp on a main shaft of an ultra-precision machine tool; providing a metal sheet, and detachably attaching and fixing the metal sheet to the outer cylindrical surface of the cylindrical clamp to form a metal cylinder, wherein the central line of the metal cylinder is superposed with the central axis of the main shaft; based on the structure of the micro-lens array, a cutter of the ultra-precision machine tool is enabled to machine a concave groove array on the outer surface of the metal cylinder; and detaching the metal cylinder provided with the pit array from the fixture to form the micro-lens array mold core. The micro-lens array mold core manufactured by the method has good consistency of each concave groove, and the quality of the micro-lens array mold core is greatly improved. Furthermore, the quality of the micro-lens array processed by the micro-lens array mold core is greatly improved.

Description

Microlens array mold core and manufacturing method thereof, microlens array and manufacturing method thereof

technical field

The invention relates to a microlens array mold core and a manufacturing method thereof, a microlens array and a manufacturing method thereof.

Background technique

In recent years, the use of microlens arrays has become more common in optoelectronics. Microlens arrays can be used to improve the properties of optoelectronic devices such as solar panels, photodetectors, light-emitting devices, imaging systems, etc. Currently, research on microlens arrays is mainly focused on imaging technologies, such as photography, 3D images and display technologies.

The traditional manufacturing methods of the microlens array mainly include the following types: the microlens array is made by processing optical plastics such as injection, casting, hot pressing, and turning. However, these traditional methods have the following defects: high manufacturing cost, long time consumption, and the surface smoothness and consistency of the microlens are not high enough.

In recent years, there has been a method for making microlens arrays with ultra-precision CNC machine tools, which mainly includes the following steps: 1) making a metal mold core with a dimple array; 2) forming a microlens array by injection molding the metal mold core .

When making a metal mold core, install a flat metal plate on the end face of the main shaft, and precisely control the tool path according to the shape of the microlens array to cut out a dimple array that matches the microlens array on one side of the flat metal plate , thus making the metal mold core. The machining sequence of the tool for each dimple in the dimple array is sequentially cutting from the center to the outer periphery, and on the XY plane, the path of the cutting point of the tool is in a spiral shape.

In the optical three-dimensional micro-coordinate measurement system, the metal mold core made by the above-mentioned traditional method was checked, and it was found that the surface of the metal mold core had at least the following defects: each dimple of the metal mold core had scratches formed by cutting tools, and The scratch position is irregular, so the consistency of each dimple in the metal mold core is poor. The microlens array molded by the metal mold core also has the problem of poor uniformity of each microlens.

Contents of the invention

One of the main purposes of the present invention is to overcome at least one defect of the above-mentioned prior art, and provide a method for manufacturing a microlens array mold core, which can produce a microlens array mold core with good consistency of the dimples;

Another main purpose of the present invention is to provide a method for manufacturing a microlens array and the microlens array.

In order to realize the above-mentioned purpose of the invention, the present invention adopts following technical scheme:

According to one aspect of the present invention, a kind of manufacturing method of microlens array mold core comprises the following steps:

A cylindrical fixture is provided, and the cylindrical fixture is coaxially installed on the spindle of an ultra-precision machine tool;

A metal sheet is provided, and the metal sheet is detachably bonded and fixed on the outer cylindrical surface of the cylindrical fixture to form a metal cylinder, the centerline of the metal cylinder coincides with the central axis of the main shaft;

Based on the structure of the microlens array, the tool of the ultra-precision machine tool processes a dimple array on the outer surface of the metal cylinder; the metal cylinder processed with the dimple array is detached from the main shaft to form the microlens array mold core .

In one embodiment, after the metal cylinder is detached from the cylindrical fixture, a step of arranging the metal cylinder into metal sheets is further included.

In one embodiment, the method further includes the following steps: selecting a suitable area of the dimple array on the metal sheet, and removing the part outside the suitable area.

In one embodiment, during the process of machining the dimple array, the feeding direction of the tool is perpendicular to the central axis of the main shaft.

In one embodiment, during the process of machining each row of dimples in the dimple array, the coordinates (C _c , X _c , Z _c ) of the tool cutting point of the ultra-precision machine tool are controlled to satisfy formula (1):

Wherein (X _p , Y _p , Z _p ) are the coordinates of the cutting point in the plane coordinate system (X, Y, Z), satisfying formula (2):

Among them, L is the length of the microlens array, W is the width of the microlens array, p is the diameter of each microlens in the microlens array; D is the outer diameter of the metal cylinder, R is the tool radius, and k is the row of the microlens array serial number, and k=0,1...; n is the serial number of each microlens in each row of microlens array, n=0,1,2...; the tool processes the dimple array row by row Each row of dimples.

According to another aspect of the present invention, a microlens array mold core is made by the manufacturing method of the microlens array mold core described in the present invention.

According to one aspect of the present invention, a kind of fabrication method of microlens array also includes the following steps:

It is provided that the microlens array mold core is made by the manufacturing method of the microlens array mold core according to the present invention;

A mold is provided, which includes two molds that cooperate with each other, wherein one of the molds has a mold groove; the microlens array mold core is put into the mold groove, and the microlens array mold core is placed on the surface of the microlens array mold core. Under the circumstances, make the microlens array mold core protrude towards another mold direction;

Injection molding: closing the two molds of the mold, and injecting molding material into the cavity to obtain the microlens array.

In one embodiment, the process parameters of the injection molding process are: the mold temperature is 100-110°C, the injection temperature is 225-235°C, the holding pressure is 1100-1300MPa, the holding time is 15-25 seconds, the cooling time 25 to 35 seconds. Further, the technical parameters of the injection molding process are as follows: the mold temperature is 105° C., the injection molding temperature is 229° C., the holding pressure is 1200 MPa, the holding time is 20 seconds, and the cooling time is 30 seconds.

According to another aspect of the present invention, a microlens array is made by the manufacturing method of the microlens array described in the present invention.

It can be seen from the above technical solution that the advantages and positive effects of the present invention are: in the manufacturing method of the microlens array mold core of the present invention, the metal sheet is detachably bonded and fixed on the outer cylindrical surface of a cylindrical fixture to form a metal Cylinder, the cutter processes dimple arrays line by row on the outer surface of the metal cylinder to form a microlens array core, which can reduce the scratches of the tool on the surface of the dimples. The performance is good, and the quality of the microlens array mold core is greatly improved. Furthermore, the quality of the microlens array processed by the microlens array mold core is also greatly improved.

Description of drawings

Various objects, features and advantages of the present invention will become more apparent by considering the following detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The drawings are merely exemplary illustrations of the invention and are not necessarily drawn to scale. In the drawings, the same reference numerals designate the same or similar parts throughout. in:

FIG. 1 is a schematic flowchart of a method for manufacturing a microlens array according to an exemplary embodiment of the present invention.

Fig. 2 is a schematic diagram showing the positional relationship between the main shaft, the tool and the metal cylinder in the manufacturing method of the microlens array mold core according to an exemplary embodiment of the present invention.

Fig. 3A is a schematic structural diagram of a microlens array according to an exemplary embodiment of the present invention.

Figure 3B is a side view of Figure 3A.

Fig. 4 is a graph showing experimental measurement results of a microlens array core according to an exemplary embodiment.

detailed description

Example embodiments will be described more fully hereinafter with reference to the accompanying drawings. Example embodiments may, however, be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus their detailed descriptions will be omitted.

Manufacturing method of microlens array mold core

Referring to FIG. 1 , FIG. 1 is a schematic flowchart of a method for manufacturing a microlens array according to an exemplary embodiment of the present invention, and the schematic flowchart includes a manufacturing process of a microlens array mold core. The manufacturing method of the microlens array mold core shown according to an exemplary embodiment of the present invention includes the following steps:

Provide a cylindrical fixture 100, install the cylindrical fixture 100 on the end of the spindle of an ultra-precision machine tool, and make the centerline of the cylindrical fixture 100 coaxial with the central axis of the machine tool spindle. The cylindrical jig 100 may be a cylinder, but the present invention is not limited thereto. In the present invention, the cylindrical fixture 100 can also be of any other structure, as long as it has a cylindrical outer surface.

A metal sheet 10 is provided, and the metal sheet 10 may be a copper sheet or an aluminum sheet or other metal sheets. The metal sheet 10 is detachably bonded and fixed on the outer cylindrical surface of the cylindrical fixture 100 to form a metal cylinder, and the centerline of the metal cylinder coincides with the central axis of the main shaft. The metal sheet 10 can be fixed on the cylindrical fixture 100 by bonding, snap connection or any other detachable connection, and the metal sheet 10 is flatly attached to the outer surface of the cylindrical fixture 100 so as to form a shaft coaxial with the main axis. metal cylinder.

Based on the structure of the microlens array, the tool 200 of the ultra-precision machine tool processes the dimple array 20 on the outer surface of the metal cylinder. Wherein, the tool 200 of the ultra-precision machine tool can be a single-point diamond tool with a circular arc cutting edge. Since the microlens array mold core manufactured by the manufacturing method of the microlens array mold core of the present invention is for processing the microlens array, the microlens array mold core and the microlens array have consistency and complementarity in structure. Specifically, the arrangement form of each dimple in the dimple array 20 on the microlens array mold core is consistent with the arrangement form of each microlens in the microlens array, and the shape of the dimples on the microlens array mold core is consistent with that of the microlenses in the microlens array. The shape of the lens matches, and the two are in a concave-convex relationship.

The metal cylinder processed with the dimple array 20 is detached from the cylindrical fixture 100 to form a microlens array mold core.

In the manufacturing method of the above-mentioned microlens array mold core, further, after the metal cylinder is detached from the cylindrical fixture 100 , the following steps are further included: unfolding and flattening the metal cylinder to form a metal sheet with the dimple array 20 . In particular, a standing step may also be included, that is, the flat metal sheet is left standing for a period of time, such as 5-20 hours, so as to eliminate the stress formed during the process of processing the dimple array 20 .

In the manufacturing method of the above-mentioned microlens array mold core, further, after finishing and leveling the metal cylinder, the following steps are further included: selecting the dimple array 20 in a suitable area as required, and removing the part outside the suitable area, thereby forming the An array of dimples of the desired shape.

In the present invention, as mentioned above, the cylindrical fixture 100 is directly mounted on the end of the spindle of an ultra-precision machine tool, but the present invention is not limited thereto. Those skilled in the art should understand that the cylindrical fixture 100 can also be indirectly installed on the main shaft. For example, if the spindle of the ultra-precision machine tool is equipped with a vacuum chuck, the cylindrical fixture 100 can be installed on the vacuum chuck. Regardless of whether the cylindrical fixture 100 is directly installed on the main shaft or indirectly installed on the main shaft, it is necessary to ensure the coaxiality of the cylindrical fixture 100 and the main shaft.

Referring to FIG. 2 , FIG. 2 is a schematic diagram of the positional relationship between the spindle, the tool 200 and the metal cylinder in the manufacturing method of the microlens array mold core according to an exemplary embodiment of the present invention. In the method for manufacturing the microlens array core, the centerline of the metal cylinder coincides with the central axis of the main shaft, and the feeding direction of the tool 200 is perpendicular to the central axis of the main shaft. The cutter 200 reciprocates and processes each row of dimples in the dimple array 20 row by row in the X direction. For example, the tool 200 reciprocates in the X direction, and the main shaft drives the cylindrical fixture 100 and the metal cylinder to rotate clockwise. Of course, in other embodiments, the main shaft can also rotate counterclockwise. The corresponding central angle range of each row of dimples is -θ～+θ, and the θ angle can be between 5°～180°, for example, and the θ angle shown in Figure 2 is about 45°; when the last dimple in a row is processed After the dimple, retract the tool, wait for the spindle to rotate to the -θ angle position, enter the tool and process the next row of dimples until all the dimples are processed.

Referring to FIG. 3 , FIG. 3 is a schematic structural diagram of a microlens array according to an exemplary embodiment of the present invention. As mentioned above, the microlens array mold core and the microlens array have consistency and complementarity in structure. Taking the microlens array as the final processing target as shown in FIG. 3 as an example, the cutting path of the tool for processing a row of dimples in the microlens array mold core will be described below. The coordinates (X _P , Y _p , Z _p ) of the cutting point of the tool in the plane coordinate system (X, Y, Z) satisfy the following formula:

In actual processing, the dimple array in the microlens array core is processed on the cylindrical surface by controlling the C, X, and Z axes of the ultra-precision machine tool, in the cylindrical coordinate system (C', X', Z') In , the tool cutting point (C _c , X _c , Z _c ) can be obtained from its plane coordinate system coordinates (X _P , Y _p , Z _p ) through the following coordinate transformation:

Among them, L is the length of the microlens array, W is the width of the microlens array, p is the diameter of each microlens in the microlens array; D is the outer diameter of the metal cylinder, R is the radius of the tool cutting head, and k is the microlens array row number, and k=0,1...; n is the sequence number of each microlens in each row of microlens array, n=0,1,2...; the tool processes the dimples row by row Each row of dimples of the array results in an array of dimples.

Microlens array core

The microlens array mold core of the present invention is made by the above-mentioned manufacturing method of the microlens array mold core of the present invention.

Referring to FIG. 4 , FIG. 4 is a graph showing experimental measurement results of a microlens array core according to an exemplary embodiment. Experimental measurement results of the microlens array mold core of the present invention on a Zygo laser detector. At different positions of the microlens array core, 9 dimples were randomly selected, and the surface error (P-V) and spherical radius (R) of each dimple were measured. As shown in Table 1, the average value of the surface error is 0.150 μm, the standard deviation is 0.017μm; the mean value of the spherical radius is 540.469μm, and the standard deviation is 8.052μm. It can be seen that the dimples in the microlens array mold core have better consistency and higher quality. The microlens array made by the microlens array mold core also has better consistency and higher quality.

Table 1 Dimple surface error (P-V) and spherical radius (R)

Fabrication method of microlens array

See Figure 1. The manufacturing method of the microlens array of the present invention comprises the following steps:

Firstly, a microlens array mold core manufactured by the aforementioned method for manufacturing a microlens array mold core of the present invention is provided.

Provide a mould, this mold comprises the upper type mold 30 and the lower type mold 40 that cooperate with each other, wherein has die groove in the lower type mold 40; Microlens array mold core 10 is put into the mold groove, in this microlens array mold When the core 10 is bent, the microlens array core 10 is protruded toward the upper mold 30 to flatten the lens array core 10 by the pressure of injection molding. Of course, the microlens array mold core 10 can also be put into the mold cavity after finishing and leveling in advance. In other embodiments, the cavity can also be arranged in the upper mold 30 . When the size of the microlens array core 10 is inappropriate, for example too large, the microlens array core 10 can also be cut to a suitable size before being placed into the mold cavity.

Injection molding process: closing the two molds of the mold, and injecting molding material into the cavity to obtain the microlens array 300 .

In the manufacturing method of the microlens array of the present invention, further, the process parameters of the injection molding process are set as follows: the mold temperature is 105°C, the injection molding temperature is 229°C, the holding pressure is 1200MPa, the holding time is 20 seconds, and the cooling time is 30 seconds. Of course, the process parameters of the injection molding process of the present invention are not limited to the above values, and it is feasible to set the following parameter range values in other embodiments: the mold temperature is 100-110°C, the injection molding temperature is 225-235°C, and the holding pressure is 1100~1300MPa, the holding time is 15~25 seconds, and the cooling time is 25~35 seconds.

microlens array

The microlens array of the present invention is made by the above-mentioned microlens array manufacturing method of the present invention.

The above-mentioned microlens array of the present invention has higher quality and better consistency. Compared with the traditional glass photolithography method, it has higher cost performance and can be used in the research, development and production of light field cameras. Using the microlens array of the present invention, an ordinary single-lens reflex camera can be conveniently refitted into a light field camera with a light field imaging function, so as to realize functions such as increasing the depth of field and "photographing first, then focusing". In addition, the use of the microlens array of the present invention can further expand the application of light field, such as applying light field imaging to 3D rendering, video monitoring, light field microscopy and other fields, so as to realize more powerful functions of light field imaging.

Exemplary embodiments are described and/or illustrated herein in detail. However, the embodiments of the present invention are not limited to the specific embodiments described herein, rather, components and/or steps of each embodiment can be used independently and separately from other components and/or steps described herein. Each component and/or each step of one embodiment can also be used in combination with other components and/or steps of other embodiments. When introducing elements/components/etc. described and/or illustrated herein, the terms "a", "an", "the", "said" and "at least one" are used to mean that there are one or more elements /components/etc. The terms "comprising", "including" and "having" are used in an open inclusive sense and mean that there may be additional elements/components/etc. besides the listed elements/components/etc.

Claims (10)

1. A method for making a microlens array mold core, characterized in that it may further comprise the steps: A cylindrical fixture is provided, and the cylindrical fixture is coaxially installed on the spindle of an ultra-precision machine tool; A metal sheet is provided, and the metal sheet is detachably bonded and fixed on the outer cylindrical surface of the cylindrical fixture to form a metal cylinder, the centerline of the metal cylinder coincides with the central axis of the main shaft; Based on the structure of the microlens array, the tool of the ultra-precision machine tool processes a dimple array on the outer surface of the metal cylinder; Detaching the metal cylinder processed with the dimple array from the main shaft to form the microlens array mold core. 2. The manufacturing method of the microlens array mold core as claimed in claim 1, further comprising the step of arranging the metal cylinder into metal sheets after the metal cylinder is detached from the cylindrical fixture . 3. The manufacturing method of the microlens array mold core according to claim 2, further comprising the step of: selecting a dimple array in a suitable area on the metal sheet, and removing the part outside the suitable area. 4. The manufacturing method of the microlens array mold core according to claim 1, 2 or 3, characterized in that, during the process of machining the dimple array, the feeding direction of the tool is perpendicular to the central axis of the spindle. 5. the manufacture method of microlens array mold core as claimed in claim 4, is characterized in that, in processing each row dimple process of described dimple array, control the tool cutting point coordinates (C _c , X _c , Z _c ) satisfy formula (1): $\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}}{\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>\frac{\mathrm{<span\; class="notranslate">\; 180</span>}}{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}\\ {\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; D.</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}\\ {\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$ Where (X _P , Y _p , Z _p ) are the coordinates of the cutting point in the plane coordinate system (X, Y, Z), satisfying formula (2): $\left\{\begin{array}{c}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; k</span>}\\ {\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>\sqrt{{\mathrm{<span\; class="notranslate">\; R</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; p</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\\ <span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&le;</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 0</span>}\\ {\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; W</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; no</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$ Among them, L is the length of the microlens array, W is the width of the microlens array, p is the diameter of each microlens in the microlens array; D is the outer diameter of the metal cylinder, R is the tool radius, and k is the row of the microlens array serial number, and k=0,1...; n is the serial number of each microlens in each row of microlens array, n=0,1,2...; the tool processes the dimple array row by row Each row of dimples. 6. A microlens array mold core, characterized in that it is made by the manufacturing method of a microlens array mold core according to any one of claims 1-5. 7. A method for making a microlens array, comprising the following steps: Provide to make microlens array mold core by the manufacturing method of microlens array mold core as described in any one of claim 1-5; A mold is provided, which includes two molds that cooperate with each other, wherein one mold has a mold groove; the microlens array mold core is put into the mold groove, and the microlens array mold core is curved Under the circumstances, make the microlens array mold core protrude towards another mold direction; Injection molding: closing the two molds of the mold, and injecting molding material into the cavity to obtain the microlens array. 8. The manufacturing method of the microlens array according to claim 7, characterized in that, the process parameters of the injection molding process are: the mold temperature is 100-110°C, the injection molding temperature is 225-235°C, and the holding pressure is 1100°C. ～1300MPa, the holding time is 15～25 seconds, and the cooling time is 25～35 seconds. 9. The manufacturing method of the microlens array according to claim 8, wherein the process parameters of the injection molding process are as follows: the mold temperature is 105°C, the injection molding temperature is 229°C, the holding pressure is 1200MPa, and the holding time is 20 seconds and has a cooldown of 30 seconds. 10. A microlens array, characterized in that it is made by the manufacturing method of a microlens array according to any one of claims 7-9.