KR100551623B1 - Process of Producing Hybrid Lens - Google Patents

Abstract

The present invention relates to a method for manufacturing a hybrid lens using ultraviolet curing, the main object of the invention is to provide a new molding method using ultraviolet curing, and to easily produce a lens of a small pitch, the performance of the performance according to the temperature difference and pressure difference It is to enable mass production without change.

The manufacturing method of the present invention comprises a stamp manufacturing process for manufacturing a stamp to form a pattern portion at any pitch and any depth in view of the lens to be manufactured; A stamp preparation step of applying an adhesive to the back surface of the stamp completed through the stamp manufacturing process and then attaching it to a flat plate member having a horizontal level; A photopolymer coating process of washing the pattern portion of the stamp completed through the stamp preparation process and then coating a photopolymer layer thereon; A base material pressing process of placing a base material on the coated photopolymer layer through the photopolymer coating process and pressing in a vacuum state; An ultraviolet irradiation step of irradiating ultraviolet rays onto the base material pressed through the base material pressing step; In the method of manufacturing a hybrid lens using ultraviolet curing completed through a release process is removed from the stamp after the ultraviolet irradiation step is finished, spin coating a protective solvent on the pattern surface of the stamp completed through the stamp manufacturing process It is characterized by a method for producing a hybrid lens using ultraviolet curing.

Hybrid Lens, UV Curing, UV Embossing, Stamp, Photopolymer, Base Material

Description

Process of Producing Hybrid Lens using UV Curing

1 is a cross-sectional view showing the configuration of a hybrid lens

Figure 2 is a process chart showing a hybrid lens manufacturing method of the present invention.

3 is a cross-sectional view according to the manufacturing process of the present invention

<Code Description of Main Parts of Drawing>

1 stamp 2 flat plate member

3: photopolymer 4: base material

The present invention relates to a method for manufacturing a hybrid lens using ultraviolet curing, and more particularly, to produce a hybrid lens, it is characterized by manufacturing a lens by curing the photopolymer laminated on the parent material through an ultraviolet irradiation process.

Generally speaking, a hybrid lens is a type of diffractive optical element lens, and the diffractive optical element lens is formed on a spherical lens surface with an arbitrary pitch and an arbitrary depth as shown in FIG. 1. It is a lens that can diffract light by forming aspheric surface and aspheric surface.

The diffractive optical element lens is a collimated lens (LD, LSU (Laser Scanning Unit), CD, DVD, etc. (lens that converts the light scattered or concentrated in the laser into a collimated or parallel light) ), And is widely used as an optical lens for display such as a project TV, and the like as an optical communication connector lens, and the size is mostly about 1 mm in diameter and a microlens having a thickness of only a few micrometers.

In the related art, the diffractive optical element lens is generally made of a material such as glass or synthetic resin. However, in recent years, a hybrid lens made of a double material has been used. This is because the deterioration of characteristics due to temperature change is small, the weight can be reduced, the numerical aperture can be made high, and the product cost can be lowered.

Methods of manufacturing such hybrid lenses include machining, epoxy molding or injection molding.

However, the machining method does not deteriorate the performance of the finished lens, but it is possible only when the pitch is 10 μm or more, and since it is limited to the rotationally symmetrical shape, it is very difficult to manufacture and the productivity is low. In addition, the epoxy molding and injection molding methods are polymer materials. Is injected into a mold in a molten state at a high temperature, and is hardened and solidified in the process of solidifying a liquid polymer, which adversely affects the performance of the lens.

Therefore, the present invention is to solve and compensate for the conventional problems as described above, the main object of the present invention is to provide a new molding method using ultraviolet curing, it is easy to manufacture a small pitch lens, temperature difference and pressure difference It is to enable mass production without any change in performance.

A characteristic method of the present invention for achieving the above object is a stamp manufacturing process for producing a stamp to form a pattern portion at any pitch and any depth in consideration of the lens to be manufactured; A stamp preparation step of applying an adhesive to the back surface of the stamp completed through the stamp manufacturing process and then attaching it to a flat plate member having a horizontal level; A photopolymer coating process of washing the pattern portion of the stamp completed through the stamp preparation process and then coating a photopolymer layer thereon; A base material pressing process of placing a base material on the coated photopolymer layer through the photopolymer coating process and pressing in a vacuum state; An ultraviolet irradiation step of irradiating ultraviolet rays onto the base material pressed through the base material pressing step; In the method of manufacturing a hybrid lens using ultraviolet curing completed through a release process is removed from the stamp after the ultraviolet irradiation step is finished, spin coating a protective solvent on the pattern surface of the stamp completed through the stamp manufacturing process It is characterized by a method for producing a hybrid lens using ultraviolet curing.

Hereinafter, the manufacturing method of the present invention will be described in more detail with reference to the accompanying drawings.

The hybrid lens manufacturing method of the present invention may also be referred to as a UV embossing manufacturing method, which is roughly divided into a stamp manufacturing process, a stamp preparation process, a photopolymer coating process, a base material pressing process, an ultraviolet irradiation process, and a release process. Manufacture.

Stamp (1) manufacturing process is made in consideration of the lens to be produced, the material of the stamp can be made using nickel (Ni) or silicon (Si), the pattern portion 11 of the surface is any pitch (P) ) And any depth (D).

When manufacturing stamps by machining, the parallelism management is relatively easy, but in the case of electroplating, the fixing of the stamp becomes a very important variable. For this purpose, the jig must be thoroughly managed.

At this time, the stamp made of nickel (Ni) is made by using electroplating, wrapping may occur or there may be stress, but there is no fear of deformation after production, and silicon Stamps made of (Si) have a concern of deformation after manufacturing and have a disadvantage of poor durability, but there is no fear of stress generation and good releasability during replication.

The stamp preparation process is prepared by spin coating a protective solvent on the pattern surface of the stamp completed through the stamp manufacturing process, applying an adhesive on the back surface, and then attaching it to the flat plate member 2 having a horizontal level. .

The photopolymer coating process is to wash the pattern portion of the stamp completed through the stamp preparation process with acetone, and then to coat the photopolymer layer 3 thereon.

As described above, when applying the photopolymer, bubbles should not be generated on the surface of the stamp. In particular, in the case of the basic UV curing agent, care should be taken because bubbles are not cured.

Which of the photopolymers to use in the present invention is very important to select, which basically requires mechanical strength and thermal stability, environmental resistance is also important to be able to prevent peeling phenomenon, yellowing phenomenon, viscosity, release property is also important.

That is, it is necessary to pay attention to prevent the peeling phenomenon because it may be peeled off with the base material according to the environmental conditions, and yellowing phenomenon due to secular variation is generally a defect of the polymer that occurs a lot, so there should be no such yellowing phenomenon. Of course.

From the standpoint of molding, it is judged to be excellent in workability if the viscosity is high, but since the pattern to be replicated is hundreds of nm to several μm, if the viscosity is high, the fluidity may not be sufficient and the filling of the pattern may not be perfect. It is good to use

In addition, molds and molds on which the patterns are recorded should be easily released, and have strong adhesion between the base materials and are advantageous for ultraviolet embossing.

However, since most UV irradiation photopolymers are used and manufactured for adhesion purposes, in order to apply to UV embossing, suitable additives must be mixed to have effective adhesive properties according to mechanical properties and types of base materials.

The base material crimping process is a process of placing and pressing a base material (eg, a glass material) on a photopolymer layer coated through the photopolymer coating process.

Since bubbles should not be generated when the photopolymer is applied onto the stamp, it is preferable to remove the bubbles in the process of pressing the base material 4, and an effective method of removing the bubbles is to pressurize in a vacuum state.

The ultraviolet irradiation process is a process of irradiating ultraviolet rays onto the base material pressed through the base material pressing process.

When irradiating UV light, it is important to irradiate the entire area with uniform concentration and contrast. Otherwise, due to the difference in curing rate, cracking due to bubble or stress may occur.

After releasing the product from the stamp after irradiation with ultraviolet rays, the hybrid manufacturing process using UV curing ends.

<Example>

-Stamp processing

Stamping can be made using machining, electroplating, semiconductor processing and hot embossing. In this embodiment, the machining using DTM (Diamond turning M / C) will be described.

The design data is shown below.

13.445mm radius of glass substrate

DOE part

Radius = -12.581

K = -1.8461

A = 3.2020E-05

B = 1.6381E-07

C = 1.1561E-10

Redesign the mold taking into account the shrinkage of the polymer. If the shrinkage is 2.5%, the design data of the mold is as follows.

Radius = -12.5595

K = -5.68330E-01

A = 3.20200E-05

B = 1.63356 E-07

C = 1.28365E-10

The mold is processed using machining. NC code is generated using the phase function, and the mold is processed in the DTM using the generated NC code, and materials such as Al and Ni may be used. The stamp measures 18.0mm in diameter and the DOE (Diffractive Optial Element) part is 16.0mm. The pattern of the processed mold has a pitch of about 0.5 mm at the center, and the pitch is narrowed sequentially, and has a pitch of 25 μm at the outside. The depth of the pattern determines the diffraction efficiency and the refractive index was processed to a depth of 1.59 μm based on 1.5. In the case of a stamp made of Al, since the releasability with the photopolymer is poor during the replication process, the secondary stamp is manufactured using non-polar engineering plastic. The process used here is molded by a hot embossing method, the temperature is raised to near the glass transition temperature to the mold and the plastic base material and pressurized to produce a stamp. The stamp thus produced is used for ultraviolet curing.

-Photopolymer Coating Process

The actual coating thickness of the photopolymer depends on the shape and thickness variations of the mold and the glass substrate. In this embodiment, since the surface is curved rather than flat, a certain amount of photopolymer is injected into the center of the stamp, and then the thickness is adjusted by pressing a glass substrate. It is about 40㎛ at the center and about 200㎛ at the outside.

-Base material crimping process

The pressing pressure is determined in consideration of the viscosity of the polymer and the thickness of the polymer layer. In this example, the thickness was generated by applying a pressure of 10 gf. In order to remove the bubbles, the chamber containing the stamp and the glass substrate is sealed to maintain a vacuum. In order to irradiate ultraviolet rays, the glass substrate side is sealed using a silica substrate, and the silica substrate side is irradiated with ultraviolet rays.

-UV irradiation process

Irradiation of ultraviolet rays depends on the characteristics of the photopolymer used. For the photopolymer used in the present embodiment, the energy required for curing is 2.0J / cm 2 and for the UV rays used, 0.5J / cm 2, the irradiation time of 4 sec or more is sufficient. . In addition, in order to irradiate ultraviolet rays uniformly, the uniform irradiation optical system may be configured or the irradiated object may be rotated to cure. In this embodiment, since the size is relatively small, the uniform irradiation optical system was used.

-Release process

The release process uses the method of grasping the base material surface using pneumatic pressure and care should be taken not to damage the release surface by contact with the equipment.

In the case of the hybrid lens produced above, the PV value of the transmission wave front aberration is 0.1 lambda, which satisfies the design specification of 0.25 lambda.

The adjustment of the mold and the glass substrate, the time for maintaining the vacuum state, and the UV irradiation time add up to about 20 sec, which is sufficient for mass production.

As described in detail above, the present invention prepares a hybrid lens, and prepares a stamp in which an arbitrary pattern is formed, and then, a photopolymer is coated thereon, and the base material is pressed again to be manufactured by UV curing. The lens is also easy to manufacture and has the advantage of mass production of high quality products with no performance change due to temperature and pressure differences.

Claims (1)

A stamp manufacturing process for manufacturing a stamp to form a pattern portion at an arbitrary pitch and an arbitrary depth in view of the lens to be manufactured; A stamp preparation step of applying an adhesive to the back surface of the stamp completed through the stamp manufacturing process and then attaching it to a flat plate member having a horizontal level; A photopolymer coating process of washing the pattern portion of the stamp completed through the stamp preparation process and then coating a photopolymer layer thereon; A base material pressing process of placing a base material on the coated photopolymer layer through the photopolymer coating process and pressing in a vacuum state; An ultraviolet irradiation step of irradiating ultraviolet rays onto the base material pressed through the base material pressing step; In the manufacturing method of the hybrid lens using ultraviolet curing completed after the ultraviolet irradiation step is completed, the release step is removed from the stamp, The method of manufacturing a hybrid lens using UV curing, characterized in that the spin coating of the protective solvent on the pattern surface of the stamp completed through the stamp manufacturing process.

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