TWI428235B - Method for fabricating double-sided - Google Patents

Description

Double-sided lens manufacturing method

The invention relates to the technical field of lens manufacturing, and in particular to a method for manufacturing a double-sided lens.

The Softlithography process is a method for fabricating micro-sized optical components. It uses a mold transfer and transfer method to rapidly fabricate a micro-sized structure, and the cost is low, and the resolution is higher than that of photolithography. . Please refer to the literature: Teng-Kai Shin, Jeng-Rong Ho, and J.-W. John Cheng, A New Approach to Polymeric Microlens Array Fabrication. Using Soft Replica Molding, IEEE Photonics Technology Letters, vol. 16, no. 9, 2004. The soft lithography process can be divided into five according to the principle, namely: 1. replica molding (REM); 2. microtransfer molding (MTM); 3. capillary microforming (micromolding in capillaries) , MIMIC); 4. Solvent-assisted micromolding (SAMIM); 5. Microcontact printing (MCP).

The replication forming system is provided on the molding surface of a mold by using a prepolymerized polymer in a molten state. Then, after curing, overmolding (ie, removing the mold), an optical element having a microstructure corresponding to the molded surface is obtained. However, this method uses only one mold to make the lens, and thus the optical element thus produced has only one side having a microstructure, which cannot meet the requirements for producing a double-sided lens.

In view of this, it is necessary to provide a double-sided lens manufacturing method to improve the optical performance of the double-sided lens.

Hereinafter, a method of manufacturing a double-sided lens will be described by way of examples.

The double-sided lens manufacturing method comprises the following steps: first, two lens preforms are formed, the materials of the two lens preforms are polymer materials, and each lens preform has a first surface and a first The surface is opposite the second surface; each of the first surfaces has a complex lens structure. Next, the two lens preforms are subjected to an oxy-plasma surface modification treatment so that the polymer material of the second surface of the two lens preforms forms a group having irreversible bonding properties. Again, the second surfaces of the two lens preforms are brought into contact, and the two lens preforms are bonded to form a double-sided surface by irreversible bonding between the two groups having irreversible bonding properties of the second surface. Lens preform. Finally, the double-sided lens preform is cut along the edge of the lens structure to form a plurality of double-sided lenses. The oxygen plasma surface modification treatment has an oxygen ignition voltage controlled at 1500V to 1600V, and the treatment time is controlled from 70 seconds to 60 seconds.

Compared with the prior art, the double-sided lens manufacturing method forms a lens preform having a first surface and a second surface through an oxygen plasma surface modification treatment to form a group having irreversible bonding properties on the surface of the polymer. . After the second surface of the two lens preforms are in contact, irreversible bonding between the groups having irreversible bonding properties forms a covalent bond having a strong bonding force, so that the two lens preforms are bonded to each other to form a double-sided surface. The double-sided lens preform of the lens structure can be obtained by cutting a plurality of double-sided lenses. The manufacturing method is simple and efficient, and the double-sided lens obtained thereby shortens the focusing length and effectively improves the optical imaging quality.

10‧‧‧Mold

11‧‧‧Molded surface

12‧‧‧Microstructure

20‧‧‧Lens preforms

201‧‧‧ Polymer materials

21‧‧‧ first surface

22‧‧‧ second surface

23‧‧‧ lens structure

30‧‧‧Double lens preforms

40‧‧‧Double-sided lenses

FIG. 1 is a schematic structural view of a mold provided by an embodiment of the present technical solution.

2 is a schematic view showing a mold for forming a lens according to a mold provided in an embodiment of the present technical solution.

FIG. 3 is a schematic structural view of a lens preform provided by an embodiment of the present technical solution.

4 is a schematic structural view of a double-sided lens preform provided by an embodiment of the present technical solution.

FIG. 5 is a schematic structural view of a double-sided lens provided by an embodiment of the present technical solution.

The method for manufacturing the double-sided lens provided by the embodiment of the present technical solution will be further described in detail below with reference to the accompanying drawings and embodiments.

Referring to FIG. 1 to FIG. 4 , the method for manufacturing the double-sided lens provided by the embodiment of the present technical solution includes the following steps.

In the first step, a mold 10 is provided.

Referring to FIG. 1 , the mold 10 has a molding surface 11 , and the molding surface 11 is provided with a plurality of microstructures 12 . The microstructures 12 are arranged in an array for forming a lens structure having an array arrangement corresponding to the microstructures 12. The microstructure 12 can be a spherical or aspherical microstructure, or a concave or convex microstructure, the specific structure of which can be determined according to the shape of the lens to be fabricated.

In the present embodiment, a mold 10 is provided, and the molding surface 11 of the mold 10 is provided with a plurality of concave microstructures 12 for use in subsequently fabricating a lens preform having a convex lens structure. It can be understood that the molding surface 11 of the mold 10 can also be provided with a plurality of convex microstructures for use in fabricating a lens preform having a concave lens structure.

The mold 10 can be made of a material having a certain rigidity such as plastic or metal. Preferably, the mold 10 has aluminum as a substrate which is formed into a mold 10 by super finishing according to design parameters. The mold 10 can be further subjected to a mold release treatment to facilitate subsequent removal of the formed lens from the mold 10 to avoid mucosal phenomena.

In the second step, the lens preform 20 is produced by a replication molding method.

Referring to FIG. 2, a certain volume of molten polymer material 201 is placed on the molding surface 11 of the mold 10. Then, the polymer material 201 is cured to form a structure corresponding to the mold 10, and finally, the lens preform 20 is obtained by overturning, as shown in FIG. The polymer material 201 may be a polymer material such as polydimethylsiloxane (PDMS), polymethylmethacrylic (PMMA), or polyethylene terephathalate (PET). And the polymer material can form a group having irreversible bonding properties in the subsequent surface treatment of the oxygen plasma. In this embodiment, a molten polydimethylsiloxane (PDMS) is applied to the molding surface 11 of the mold 10 by spin coating, and the thickness of the coated PDMS is controlled. To control the thickness of the lens preform 20. Then, it was baked at 125 ° C for 15 minutes, and the lens preform 20 was obtained by overmolding. Of course, the polymer material 201 may be placed on the molding surface 11 by deposition, spraying, or direct dropping.

The lens preform 20 has a first table corresponding to the shape of the molding surface 11 of the mold 10. Face 21 and second surface 22 opposite first surface 21. The first surface 21 has a lens structure 23 corresponding to the microstructures 12. The lens structure 23 corresponds to the microstructure 12: when the mold 10 has a concave microstructure 12, the lens preform 20 has a convex lens structure 23; when the mold 10 has a convex microstructure 12, The lens preform 20 has a concave lens structure 23.

In the present embodiment, the mold 10 has a plurality of concave microstructures 12, and correspondingly, the formed lens preform 20 has a convex lens structure 23 corresponding to the plurality of concave microstructures 12, the lens structure 23 is arranged in an array, and the second surface 22 is planar.

Two lens preforms 20 were produced by the replication molding method for forming a double-sided lens preform. In the present embodiment, two lens preforms 20 having a plurality of convex lens structures 23 are formed by PDMS using a mold 10. Of course, the two lens preforms 20 can also be made of the same other polymer materials or different polymer materials, as long as irreversible bonding can be achieved.

In the third step, the lens preform 20 is subjected to a plasma surface modification treatment.

In this embodiment, the second surface 22 of the two lens preforms 20 is subjected to surface modification treatment by oxygen plasma to form an alkyl group of the polymer material 201 constituting the second surface 22 of the lens preform 20. Converted to a hydroxyl group. In the present embodiment, the polymer material 201 is PDMS. Specifically, the two lens preforms 20 were placed in a vacuum oxygen plasma cleaner for surface modification treatment. Prior to PDMS surface treatment by oxygen plasma, the PDMS of the second surface 22 comprises a Si-CH3 group (i.e., an alkyl group) that exhibits strong hydrophobicity. The oxygen radical generated by the plasma is very active and easily reacts with the hydrocarbon. Therefore, the PDMS of the second surface 22 after the surface treatment of the oxygen plasma forms a large amount of Si-OH groups (ie, hydroxyl groups), which is strong. Hydrophilic. A condensation reaction easily occurs between the Si-OH groups to form a Si-O-Si covalent bond having a high strength, thereby achieving irreversible bonding.

When the surface modification treatment was carried out in a vacuum oxygen plasma cleaner, pure oxygen was charged into the vacuum chamber of the washing machine, and then evacuated to 27 Pa. By repeatedly charging 2 to 3 times and turning off the oxygen, the pressure at the bottom of the vacuum chamber can reach 27 Pa. Then, a voltage of 1400 V to 2000 V is applied to cause oxygen in the chamber to illuminate, thereby generating oxygen plasma. By vacuuming and refilling the oxygen, the purity of oxygen formed by high vacuum can be achieved by repeatedly charging pure oxygen. Vacuum pumps such as oil pumps or diffusion pumps and molecular pumps can be used for vacuuming.

In addition, the bonding strength is related not only to the oxygen ignition voltage but also to the processing time of the oxygen plasma to the lens preform 20. Preferably, when the oxygen ignition voltage is controlled between 1500V and 1600V, the processing time is controlled from 70 seconds to 60 seconds.

In the fourth step, the two lens preforms 20 are attached.

The two second surfaces 22 of the two lens preforms 20 are disposed opposite each other such that the central optical axis of each lens structure 23 of one lens preform 20 and each lens structure 23 of the other lens preform 20 The central optical axes are on the same line. Then, the two second surfaces 22 are in contact, and the two lens preforms 20 are bonded by the covalent bond of the Si-O-Si bond formed by the condensation reaction by the irreversible bonding property of the Si-OH groups, thereby sticking to each other. The double-sided lens preform 30 having a double-sided lens structure is formed.

The PDMS of the second surface 22 that has not been surface treated appears to be hydrophobic, while the PDMS of the second surface 22 is treated with oxygen plasma to cause the PDMS of the second surface 22 to produce Si-OH groups, which exhibits strong hydrophilicity. However, the prolongation of the PDMS placement time of the surface treated second surface 22 causes the SiMS group of the second surface 22 to gradually decrease, and after about 24 hours, the Si-OH group substantially disappears, so that the second The PDMS of surface 22 is substantially restored to a hydrophobic state. The Si-OH group has an irreversible bonding ability, and if the Si-OH group of the PDMS of the second surface 22 is reduced, the bonding strength of the PDMS of the second surface 22 is lowered. Therefore, the two plasma preforms 20 are subjected to an oxygen plasma surface treatment step and The shorter the time interval between the contacting steps of the second surface 22 of the two lens preforms 20, the higher the bonding strength. Preferably, the time interval is controlled to be optimal within 3 to 5 minutes.

In order to achieve a better bonding strength, after the above-mentioned bonding to form the double-sided lens preform 30, the double-sided lens preform 30 can also be placed at a temperature of 90 to 120 degrees (such as an oven) to keep warm. The second surface 22 of the two lens preforms 20 is completely wetted for 1.5 hours to 2 hours to improve the stability of the double-sided lens preform 30 formed by the bonding of the two lens preforms 20.

In the fifth step, the double-sided lens preform 30 is cut.

Referring to FIG. 5, finally, the adjacent lens structures of the double-sided lens preform 30 are cut along a central optical axis direction parallel to the lens structure 23 to form a plurality of double-sided lenses 40. In this embodiment, the double-sided lens 40 is a double convex double-sided lens. The double-sided lens preform 30 can be cut using a wafer cutter (not shown) during cutting. The wafer cutting machine is a quartz wafer cutting machine, a silicon wafer cutting machine or an ultraviolet laser wafer cutting machine.

It can be understood that the double-sided lens 40 can also be a double-sided or double-sided concave lens. As long as the mold 10 having the corresponding structure is provided in the first step, then the second to fifth steps are repeated to produce the double-sided lens 40 having a double concave or a convex side concave.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

40‧‧‧Double-sided lenses

Claims (9)

A double-sided lens manufacturing method comprising the steps of: fabricating two lens preforms, the two lens preforms being a polymer material, each lens preform having a first surface and a first surface opposite to the first surface a second surface, each of the first surfaces has a complex lens structure; the two lens preforms are subjected to an oxygen plasma surface modification treatment such that the polymer material of the second surface of each lens preform forms an irreversible bond a group having the same property; contacting the second surface of the two lens preforms, and prematurely bonding the two lenses by irreversible bonding between the two groups having irreversible bonding properties of the second surface Forming a double-sided lens preform; cutting the double-sided lens preform along an optical axis parallel to a central optical axis of the lens structure to form a plurality of double-sided lenses; the oxygen plasma surface-modified oxygen The starting voltage is controlled from 1500V to 1600V, and the processing time is controlled from 70 seconds to 60 seconds. The double-sided lens manufacturing method according to claim 1, wherein the two lens preforms are each made of a polydimethyloxane material having a Si-CH ₃ group on the surface. The double-sided lens manufacturing method according to claim 2, wherein the double-sided lens manufacturing method further comprises providing a mold for fabricating the lens preform, the mold having a plurality of micro-images corresponding to the plurality of lens structures structure. The double-sided lens manufacturing method according to claim 3, wherein the microstructures are arranged in an array. The method for producing a double-sided lens according to claim 3, wherein the lens preform is coated with a molten polydimethyl methoxy oxane in a mold by a spin coating method, and is cured by a mold. Lens preform. The double-sided lens manufacturing method according to claim 1, wherein the lens preform is made of polymethyl methacrylate or polyethylene terephthalate. The double-sided lens manufacturing method according to claim 1, wherein the oxygen plasma surface modification treatment uses a vacuum oxygen plasma cleaning machine. A double-sided lens manufacturing method comprising the steps of: fabricating two lens preforms, the two lens preforms being a polymer material, each lens preform having a first surface and a first surface opposite to the first surface a second surface, each of the first surfaces has a complex lens structure; the two lens preforms are subjected to an oxygen plasma surface modification treatment such that the polymer material of the second surface of each lens preform forms an irreversible bond a group having the same property; contacting the second surface of the two lens preforms, and prematurely bonding the two lenses by irreversible bonding between the two groups having irreversible bonding properties of the second surface Forming a double-sided lens preform; cutting the double-sided lens preform between adjacent lens structures along a central optical axis direction parallel to the lens structure to form a plurality of double-sided lenses; performing the two lens preforms The time interval between the step of treating the surface of the oxygen plasma and the step of contacting the second surface of the two lens preforms is from 3 minutes to 5 minutes. A double-sided lens manufacturing method comprising the steps of: fabricating two lens preforms, the two lens preforms being polymer materials Each of the lens preforms has a first surface and a second surface opposite to the first surface, each of the first surfaces having a plurality of lens structures; and the two lens preforms are subjected to an oxy-plasma surface modification treatment to Forming a polymer material having a second surface of each lens preform into a group having irreversible bonding properties; contacting the second surface of the two lens preforms, wherein the two second surfaces have irreversible bonds Irreversible bonding between the groups of the nature, the two lens preforms are bonded to form a double-sided lens preform; the double-sided lens is cut between adjacent lens structures along a central optical axis parallel to the lens structure The preform body forms a plurality of double-sided lenses; the double-sided lens manufacturing method further comprises: after bonding to form the double-sided lens preform, the double-sided lens preform is placed at a temperature of 90 degrees to 120 degrees, and the heat is maintained at 1.5. Insulation step from hour to 2 hours.