WO2021103152A1

WO2021103152A1 - Method for manufacturing fresnel lens metal mold

Info

Publication number: WO2021103152A1
Application number: PCT/CN2019/124716
Authority: WO
Inventors: 徐甜; 张必明; 陈晓杰
Original assignee: 诚瑞光学(常州)股份有限公司
Priority date: 2019-11-27
Filing date: 2019-12-12
Publication date: 2021-06-03
Also published as: CN111103640B; CN111103640A

Abstract

Disclosed is a method for manufacturing a Fresnel lens metal mold. The method comprises the following steps: step S1, providing a single-cavity master mold (1); step S2, covering a first Fresnel-structured groove (10) of the single-cavity master mold (1) with a first plastic soft template (2) to prepare Fresnel soft templates (2a); step S3, respectively fixedly arranging a plurality of Fresnel soft templates (2a) in a second plastic soft template (4) to obtain a characteristic soft template (4a); step S4, performing conductive processing on the side of the characteristic soft template (4a) provided with a Fresnel structure (21a) to form a metal layer; and step S5, performing electroforming processing on the side, provided with the metal layer, of the characteristic soft template (4a) which is subjected to conductive processing to form a metal electroforming layer (7), and demolding the characteristic soft template (4a) and the metal electroforming layer (7) so as to obtain a Fresnel lens metal mold (7a). Compared with the related technology, the method for manufacturing the Fresnel lens metal mold is low in manufacturing costs and high in machining precision.

Description

Method for making Fresnel lens metal mold

Technical field

The invention relates to the field of optical lens manufacturing, in particular to a method for manufacturing a Fresnel lens metal mold.

Background technique

In the field of optical lenses, the Fresnel lens has the characteristics of lightness and thinness, and at the same time has good optical performance, so that the Fresnel lens is widely used in various optical application scenarios. The molds used in the production of Fresnel lenses have also become the focus of research in the industry. Among them, in order to improve the production efficiency of Fresnel lenses, it is often necessary to produce metal molds of Fresnel lenses with multiple Fresnel structures.

The related technology of the Fresnel lens metal mold manufacturing method includes the following three types:

1. Diamond processing method: The metal substrate is processed by diamond turning to produce multiple single-cavity Fresnel lens master molds, and the multiple single-cavity Fresnel lens master molds are spliced into a whole Multi-cavity Fresnel lens metal mold, but the diamond processing cost is very high;

2. Photolithography: Use photolithography equipment to process the metal substrate to obtain a full-page multi-cavity Fresnel lens metal mold, but because the photolithography equipment is more expensive, the processing cost is higher;

3. Electroforming copying method: firstly process a single-cavity Fresnel lens master mold, and use electroforming copying method to copy multiple single-cavity Fresnel lens master molds, and make multiple single-cavity Fresnel lens masters. The molds are spliced to obtain a full-page multi-cavity Fresnel lens metal mold, but during this process, demolding fracture defects are prone to occur. After multiple replications, the structure surface defects increase, and it is difficult to ensure the structural accuracy of the multi-cavity mold.

technical problem

Based on the above analysis, in the related technology, the above-mentioned three methods cannot simultaneously satisfy the two conditions of low processing cost and high accuracy of the Fresnel lens metal mold with multiple Fresnel structures.

Therefore, it is necessary to provide a new Fresnel lens metal mold manufacturing method to solve the above technical problems.

Technical solutions

The purpose of the present invention is to provide a method for manufacturing a Fresnel lens metal mold with low manufacturing cost and high processing accuracy.

To achieve the above objective, the present invention provides a method for manufacturing a Fresnel lens metal mold. The method includes the following steps:

Step S1: Provide a single-cavity master mold; wherein the single-cavity master mold includes a main body part and a first Fresnel structure groove formed in the main body part;

Step S2: The first plastic soft template is covered on the first Fresnel structure groove of the single-cavity mother mold to form a Fresnel soft template; wherein, the Fresnel soft template includes the same The Fresnel structure that matches the groove of the first Fresnel structure;

Step S3, fixing and installing a plurality of the Fresnel soft template in a second plastic soft template to obtain a characteristic soft template; wherein, the second plastic soft template includes a plurality of soft plastic templates for installing the The limit tooling holes of the Nel soft template, a plurality of the limit tool holes are arranged at intervals, and the limit tool holes are arranged in a one-to-one correspondence with the Fresnel soft template;

Step S4: Conduct conduction treatment on the side of the feature soft template where the Fresnel structure is configured to form a metal layer;

Step S5, electroforming is performed on the side of the feature soft template after the electrical conductivity treatment where the metal layer is disposed to form a metal electroforming layer, and releasing the feature soft template from the metal electroforming layer To obtain a Fresnel lens metal mold; wherein, the Fresnel lens metal mold includes a plurality of second Fresnel structure grooves spaced apart from each other, and the second Fresnel structure grooves and the Fresnel structure grooves are Structure matching.

Preferably, the step S2 specifically includes the following sub-steps:

Step S21, covering the first plastic soft template on the single cavity master mold and completely covering the first Fresnel structure groove;

Step S22, heating the single-cavity master mold to a first preset temperature to soften the first plastic soft template;

Step S23, continuously applying pressure to the first plastic soft template within a preset time, so that the first plastic soft template softened by heating completely fills the first Fresnel structure groove;

Step S24, cooling the temperature of the single-cavity master mold to a second preset temperature, and taking out the first plastic soft template to obtain the Fresnel soft template; wherein, the second preset temperature is less than the The first preset temperature.

Preferably, the first preset temperature is between 80°C and 150°C; the preset time is 10-30 minutes; the second preset temperature is less than or equal to 50°C; and the applied pressure is 200N.

Preferably, the step S3 specifically includes: step S31, attaching an electrostatic film to one side of the second plastic soft template;

Step S32, placing a plurality of the Fresnel soft templates in a plurality of the limiting tool holes, and making the Fresnel structure surface of the Fresnel soft template face the electrostatic film;

Step S33: Glue the surfaces of the multiple Fresnel soft templates that are opposite to the Fresnel structure surface to fix the multiple Fresnel soft templates to the second plastic soft template;

Step S34, removing the electrostatic film to obtain the characteristic soft template.

Preferably, the step S32 further includes: cutting the Fresnel soft template so that the outer dimension of the Fresnel soft template matches the limiting tooling hole.

Preferably, in the step S32, when the Fresnel soft template is cut, the Fresnel structure is positioned at the center of the Fresnel soft template.

Preferably, in the step S4, the conductive treatment method is an electrodeposition manufacturing process.

Preferably, the first plastic soft template includes any one of polycarbonate, polyvinyl chloride and organic glass.

Preferably, the second plastic soft template includes any one of polycarbonate, polyvinyl chloride and organic glass.

Preferably, the thickness of the single cavity master mold is 8 mm, and the diameter of the first Fresnel structure groove is 100 mm.

Preferably, the thickness of the first plastic soft template and the second plastic soft template are both 1 mm.

Preferably, in the step S4, the metal layer is Ni with a thickness of 100 nm.

Preferably, in the step S5, the metal electroformed layer is Ni, and its thickness is less than 500 μm.

Beneficial effect

Compared with the related art, the method for manufacturing the Fresnel lens metal mold of the present invention only needs to process a single-cavity master mold, and the single-cavity master mold can be used to continuously form a plurality of first plastic soft templates into a plurality of Fresnel molds. A soft template, a plurality of Fresnel soft templates are respectively fixedly installed in the second plastic soft template to obtain a characteristic soft template, and the side of the characteristic soft template where the Fresnel structure is configured is electrically conductive, A metal layer is formed, electroforming is performed on the side where the metal layer of the characteristic soft template is arranged after the conductive treatment, to form a metal electroforming layer, and the characteristic soft template is electroformed with the metal Layer demolding to obtain the Fresnel lens metal mold, which realizes the production of the Fresnel lens metal mold by multi-cavity simultaneous electroforming, so that this method reduces the production cost while ensuring the processing accuracy.

Description of the drawings

In order to explain the technical solutions in the embodiments of the present invention more clearly, the following will briefly introduce the drawings needed in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative work, other drawings can be obtained based on these drawings, among which:

Fig. 1 is a schematic flow diagram of a method for manufacturing a metal mold for a Fresnel lens of the present invention;

FIG. 2 is a schematic diagram of a specific flow of step S2 in FIG. 1;

FIG. 3 is a schematic diagram of a specific flow of step S3 in FIG. 1;

4 is a schematic diagram of the cooperation between the first plastic soft template and the single cavity master mold in step S21 in FIG. 2;

5 is a schematic diagram of the cooperation between the first plastic soft template and the heated single-cavity master mold in step S22 in FIG. 2;

FIG. 6 is a schematic diagram of cooperation when pressure is applied to the first plastic soft membrane board in step S23 in FIG. 2; FIG.

FIG. 7 is a schematic diagram of step S24 in FIG. 2 when the Fresnel soft template is taken out;

Figure 8 is a schematic cross-sectional view of the Fresnel soft template of the present invention;

FIG. 9 is a schematic diagram of the cooperation of the Fresnel soft template and the second soft film plate in step S32 in FIG. 3;

Fig. 10 is a schematic cross-sectional view of the Fresnel soft template and the second soft film plate of Fig. 9;

FIG. 11 is a schematic diagram of the cooperation between the Fresnel soft template and the second soft film board in step S33 in FIG. 3 after glue is applied;

FIG. 12 is a schematic cross-sectional view of the Fresnel soft template and the second soft film plate of FIG. 11 after being glued;

FIG. 13 is a schematic diagram of the structure of the characteristic soft template in step S34 in FIG. 3;

Fig. 14 is a schematic cross-sectional view of the characteristic soft template of Fig. 13;

15 is a schematic diagram of the cooperation between the metal electroformed layer and the characteristic soft template in step S5 in FIG. 1;

16 is a schematic cross-sectional view of the metal electroformed layer and the characteristic soft template of FIG. 15;

Figure 17 is a schematic diagram of the structure of the Fresnel lens metal mold.

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

Please also refer to Figs. 1-17. The present invention provides a method for manufacturing a Fresnel lens metal mold. The method includes the following steps:

Step S1, a single cavity master mold 1 is provided.

Specifically, in the step S1, the single cavity master mold 1 includes a main body portion 11 and a first Fresnel structure groove 10 formed in the main body portion 11.

The single-cavity master mold 1 is made by machining. In order to ensure the precision of the single-cavity master mold 1, in this embodiment, the metal substrate is processed into the single-cavity master by diamond turning. The mold 1, essentially, is to perform turning processing on one side of the metal substrate to form a first Fresnel structure groove 10 on the main body 11 of the single cavity master mold 1. The first Fresnel structure The shape of the groove 10 is not limited, and it can be specifically designed according to the specific structure of the Fresnel lens that is actually required to be manufactured.

Here, in order to meet the processing conditions of the subsequent hot pressing process, the thickness of the single-cavity master mold 1 is between 5 mm and 10 mm, and the diameter of the first Fresnel structure groove 10 is less than or equal to 200 mm. For example, in this embodiment, the thickness of the single cavity master mold 1 is preferably 8 mm, and the diameter of the first Fresnel structure groove 10 is preferably 100 mm.

Step S2, covering the first plastic soft template 2 on the first Fresnel structure groove 10 of the single-cavity master mold 1 to form a Fresnel soft template 2a.

Specifically, in the step S2, the Fresnel soft template 2a includes a Fresnel structure 21a matching the first Fresnel structure groove 10.

Further, the step S2 specifically includes the following sub-steps:

Step S21, covering the first plastic soft template 2 on the single-cavity master mold 1 and completely covering the first Fresnel structure groove 10.

Step S22, heating the single cavity master mold 1 to a first preset temperature to soften the first plastic soft template 2; wherein, the first preset temperature is between 80°C and 150°C.

Step S23. The hot press continuously applies pressure to the first plastic soft template 2 through the hot press plate 3 within a preset time, so that the first soft plastic template 2 after heating and softening completely fills the first plastic template 2 A Fresnel structure groove 10; wherein the preset time is 10-30 minutes, and the pressure applied to the first plastic soft template 2 is preferably 200N.

Step S24, cooling the temperature of the single cavity master mold 1 to a second preset temperature, and taking out the first plastic soft template 2 to obtain the Fresnel soft template 2a; wherein, the second preset temperature The temperature is less than the first preset temperature, and the second preset temperature is less than or equal to 50°C.

After the step S2, the following preprocessing steps are further included before the step S3:

Cutting the second plastic soft template 4 so that the second plastic soft template 4 forms a plurality of the limiting tool holes 40;

The Fresnel soft template 2a is cut to make the outer dimensions of the Fresnel soft template 2a match the limiting tooling hole 40. For example, laser cutting or wire cutting is used to cut the Fresnel soft template 2a to ensure that the Fresnel structure 21a is located at the geometric center of the Fresnel soft template 2a.

In step S3, a plurality of the Fresnel soft templates 2a are respectively fixedly installed in the second plastic soft template 4 to obtain a characteristic soft template 4a.

Specifically, in the step S3, the second plastic soft template 4 includes a plurality of limiting tooling holes 40 for installing the Fresnel soft template 2a, and the plurality of limiting tooling holes 40 are mutually They are arranged at intervals, and the position-limiting tooling holes 40 and the Fresnel soft template 2a are arranged in a one-to-one correspondence.

Further, the step S3 specifically includes the following sub-steps:

Step S31, attach an electrostatic film 5 to one side of the second plastic soft template 4.

Step S32, placing a plurality of the Fresnel soft templates 2a in the plurality of the limiting tool holes 40, and making the Fresnel structure surface of the Fresnel soft template 2a face the electrostatic film 5, The Fresnel structure surface serves as the front surface of the Fresnel soft template 2a.

Specifically, the step S32 further includes: cutting the Fresnel soft template 21a, so that the outer dimension of the Fresnel soft template 21a matches the limit tooling hole 40; In the step S32, when the Fresnel soft template 2a is cut, the Fresnel structure 21a is positioned at the center of the Fresnel soft template 2a, which effectively guarantees the Fresnel soft template 2a. The positioning accuracy of the structure 21a installed on the second plastic soft template 4.

Step S33: Glue the surfaces of the multiple Fresnel soft templates 2a opposite to the Fresnel structure surfaces, that is, form a layer on the back side of the Fresnel soft templates 2a to remove the Fresnel The adhesive layer 6 where the Nel soft template 2 a and the second plastic soft template 4 are bonded, and the adhesive layer 6 fixes the plurality of Fresnel soft templates 2 a and the second plastic soft template 4.

Step S34, peel off the electrostatic film 5 to obtain the characteristic soft template 4a.

In step S4, the side of the feature soft template 4a where the Fresnel structure 2a is disposed is electrically conductive to form a metal layer.

Specifically, in the step S4, the conductive treatment method is an electrodeposition manufacturing process;

Further, the thickness of the metal layer is not limited. For example, in this embodiment, the metal layer is Ni with a thickness of 100 nm; of course, the thickness of the metal layer can be specifically set according to actual conditions .

Step S5, electroforming the side where the metal layer of the characteristic soft template 4a is arranged after the conductive treatment is performed to form a metal electroforming layer 7, and combining the characteristic soft template 4a with the metal electroforming The layer 7 is demolded to obtain a Fresnel lens metal mold 7a; wherein the Fresnel lens metal mold 7a includes a plurality of second Fresnel structure grooves 71a spaced apart from each other, and the second Fresnel structure The groove matches the Fresnel structure.

Specifically, the thickness of the metal electroformed layer 7 is not limited. In the step S5, the metal electroformed layer 7 is Ni, and its thickness is less than 500 μm; of course, the thickness of the metal layer can be based on actual conditions. Make specific settings for the situation.

It is worth mentioning that the materials of the first plastic soft template 2 and the second plastic soft template 4 are not limited, and the first plastic soft template 2 and the second plastic soft template 4 are polycarbonate. Any one of ester (PC), polyvinyl chloride (PVC) and organic glass (PMMA). In this embodiment, the material of the two is preferably organic glass (PMMA); in addition, the first plastic is soft The thickness of the template 2 and the second plastic soft template 4 is also unlimited. In this embodiment, the thickness of the first plastic soft template 2 and the second plastic soft template 4 are both 1 mm; of course, so The material and thickness of the first plastic soft template 2 and the second plastic soft template 4 can be specifically set according to actual production requirements.

The above are only the embodiments of the present invention. It should be pointed out here that for those of ordinary skill in the art, improvements can be made without departing from the inventive concept of the present invention, but these all belong to the present invention. The scope of protection.

Claims

A method for manufacturing a Fresnel lens metal mold, which is characterized in that the method includes the following steps:

Step S1: Provide a single-cavity master mold; wherein the single-cavity master mold includes a main body part and a first Fresnel structure groove formed in the main body part;

Step S2: The first plastic soft template is covered on the first Fresnel structure groove of the single-cavity mother mold to form a Fresnel soft template; wherein, the Fresnel soft template includes the same The Fresnel structure that matches the groove of the first Fresnel structure;

Step S3, fixing and installing a plurality of the Fresnel soft template in a second plastic soft template to obtain a characteristic soft template; wherein, the second plastic soft template includes a plurality of soft plastic templates for installing the The limit tooling holes of the Nel soft template, a plurality of the limit tool holes are arranged at intervals, and the limit tool holes are arranged in a one-to-one correspondence with the Fresnel soft template;

Step S4: Conduct conduction treatment on the side of the feature soft template where the Fresnel structure is configured to form a metal layer;

Step S5, electroforming is performed on the side of the feature soft template after the electrical conductivity treatment where the metal layer is disposed to form a metal electroforming layer, and releasing the feature soft template from the metal electroforming layer To obtain a Fresnel lens metal mold; wherein, the Fresnel lens metal mold includes a plurality of second Fresnel structure grooves spaced apart from each other, and the second Fresnel structure grooves and the Fresnel structure grooves are Structure matching.
The method for manufacturing a Fresnel lens metal mold according to claim 1, wherein the step S2 specifically includes the following sub-steps:

Step S21, covering the first plastic soft template on the single cavity master mold and completely covering the first Fresnel structure groove;

Step S22, heating the single-cavity master mold to a first preset temperature to soften the first plastic soft template;

Step S23, continuously applying pressure to the first plastic soft template within a preset time, so that the first plastic soft template softened by heating completely fills the first Fresnel structure groove;

Step S24, cooling the temperature of the single-cavity master mold to a second preset temperature, and taking out the first plastic soft template to obtain the Fresnel soft template; wherein, the second preset temperature is less than the The first preset temperature.
The method of manufacturing a Fresnel lens metal mold according to claim 2, wherein the first preset temperature is between 80°C and 150°C; the preset time is 10-30 minutes; and the first preset temperature is between 80°C and 150°C; 2. The preset temperature is less than or equal to 50°C; the applied pressure is 200N.
The method for manufacturing a Fresnel lens metal mold according to claim 1, wherein the step S3 specifically includes:

Step S31, stick an electrostatic film on one side of the second plastic soft template;

Step S32, placing a plurality of the Fresnel soft templates in a plurality of the limiting tool holes, and making the Fresnel structure surface of the Fresnel soft template face the electrostatic film;

Step S33: Glue the surfaces of the multiple Fresnel soft templates that are opposite to the Fresnel structure surface to fix the multiple Fresnel soft templates to the second plastic soft template;

Step S34, removing the electrostatic film to obtain the characteristic soft template.
The method for manufacturing a Fresnel lens metal mold according to claim 4, wherein the step S32 further comprises: cutting the Fresnel soft template to make the shape of the Fresnel soft template The size matches the limit tooling hole. 6. The method for manufacturing a Fresnel lens metal mold according to claim 5, wherein in step S32, when the Fresnel soft template is cut, the Fresnel structure is positioned at the The Fresnel soft template center is described.
4. The method for manufacturing a Fresnel lens metal mold according to claim 1, wherein, in the step S4, the conductive treatment method is an electrodeposition manufacturing process. 8. The method for manufacturing a Fresnel lens metal mold according to claim 1, wherein the first plastic soft template comprises any one of polycarbonate, polyvinyl chloride and organic glass.
The method for manufacturing a Fresnel lens metal mold according to claim 1, wherein the second plastic soft template includes any one of polycarbonate, polyvinyl chloride, and organic glass.
The method for manufacturing a Fresnel lens metal mold according to claim 1, wherein the thickness of the single cavity master mold is 8 mm, and the diameter of the first Fresnel structure groove is 100 mm.
The method for manufacturing a Fresnel lens metal mold according to claim 1, wherein the thickness of the first plastic soft template and the second plastic soft template are both 1 mm.
The method of manufacturing a Fresnel lens metal mold according to claim 1, wherein in the step S4, the metal layer is Ni, and the thickness of the metal layer is 100 nm. 13. The method for manufacturing a Fresnel lens metal mold according to claim 1, wherein in the step S5, the metal electroforming layer is Ni, and the thickness of the metal electroforming layer is less than 500 μm.

To