KR102634309B1 - Method for manufacturing core pin for injection molding of optical lens and core pin manufactured thereby - Google Patents

Abstract

A method of manufacturing an injection mold for lens molding related to the present invention includes the steps of performing basic processing on a rod-shaped material; performing nickel plating on the material; Receiving a custom shape to be applied to the plated workpiece; And it includes the step of performing finishing processing on the plated material according to the custom shape.

Description

Manufacturing method of injection mold for lens molding and mold manufactured thereby {METHOD FOR MANUFACTURING CORE PIN FOR INJECTION MOLDING OF OPTICAL LENS AND CORE PIN MANUFACTURED THEREBY}

The present invention relates to a method of manufacturing an injection mold for forming a camera lens and a mold manufactured thereby.

A camera module applied to mobile devices, including mobile phones and smartphones, or to various devices for video recording, is a component that converts images received through a lens into digital signals. These camera modules are often manufactured with an image sensor, a substrate, and a lens that transmits light to the sensor.

The lens module is made of a transparent spherical or aspherical surface to collect or diverge the light of an object and form an optical image. As the specifications of the camera module become higher, the applied lenses may also consist of multiple pieces. Lenses include light-transmitting glass or liquid, but they are manufactured by injection molding of plastic, which is excellent in mass production and can secure price competitiveness.

In general, molds used for injection molding lenses for camera modules use upper and lower angle core pins that have a lens surface shape. These core pins are a key element that determines the quality of lenses, but they also need to have sufficient durability to maintain mass production. Since the lens has a spherical or aspherical shape depending on its shape, the core pin must also be precisely processed to have such a shape.

When processing a spherical or aspherical cavity to form a lens using chrome alloy stainless steel mold steel (e.g. STAVAX), the reaction between the tool and the mold steel causes wear of the tool and damage the machined surface to obtain the desired mirror surface. difficult. Therefore, nickel plating is formed on the core pin to a certain thickness and then subjected to finishing processing to obtain an aspherical lens-shaped mold surface.

The existing method for obtaining a spherical or aspherical lens shape is to first rough and offset the core pin material ((a) in Figure 4) when there is an order for the shape of the lens to be molded ((b) in Figure 4). ), plating was performed (Figure 4(c)), and the plated material was subjected to finishing processing to complete the final shape (Figure 4(d)). However, according to this method, no matter how quickly the remaining processes are performed, plating takes more than a day, so there is a limit to shortening the overall manufacturing time.

* Related prior literature

Japanese Patent No. 5267253 (registered on May 17, 2013)

Japanese Patent Publication No. 2009-241297 (published on October 22, 2009)

Japanese Patent Publication No. 2006-051702 (published on February 23, 2006)

The purpose of the present invention is to propose a method of manufacturing an injection mold for lens molding and a mold manufactured thereby that can significantly shorten the processing time, minimize the possibility of defects due to plating, and improve the quality of surface roughness.

A method of manufacturing an injection mold for lens molding related to the present invention includes the steps of performing basic processing on a rod-shaped material; performing nickel plating on the material; Receiving a custom shape to be applied to the plated workpiece; And it includes the step of performing lens-shaped finishing processing on the plated material according to the custom shape.

As an example related to the present invention, the step of performing basic processing of the rod-shaped material may include forming a circumferential groove on the side of the end of the rod-shaped material to increase the bonding force of the plating layer. there is.

As an example related to the present invention, the step of performing nickel plating on the material may be performing electroless electroplating on the material.

As an example related to the present invention, the method of manufacturing an injection mold for lens molding may further include performing heat treatment on the plated material after plating nickel on the material.

As an example related to the present invention, the heat treatment may include at least one of tempering, annealing, and normalizing.

As an example related to the present invention, in the step of plating nickel on the material, the thickness of the nickel plating may be 30 to 700 ㎛.

As an example related to the present invention, in the step of performing nickel plating on the material, the area where the plating is performed may be the entire body of the material.

As an example related to the present invention, in the step of performing nickel plating on the material, the area where the plating is performed may be an aspherical area where a lens is formed.

As an example related to the present invention, in the step of performing nickel plating on the material, the thickness of the plating layer applied to the end of the material where the shape surface corresponding to the lens is located is thicker than the thickness of the plating layer to be applied to the side of the material. It can be formed.

The present invention also proposes a mold for forming lenses manufactured by the above method.

According to the method of manufacturing an injection mold for lens molding related to the present invention, when a custom shape is received in a state in which a plated material is prepared, a precise shape is obtained through finishing processing immediately. After ordering, roughing, plating, and finishing processing are performed. Compared to existing methods, processing time can be dramatically reduced by about 1/3.

According to an example related to the present invention, by performing heat treatment after plating, stress in the plating structure can be removed, thereby minimizing problems caused by plating defects, and improving the surface roughness of the processing surface of the plating layer and the surface quality of the lens surface. You can.

1 is a flowchart conceptually showing a method of manufacturing an injection mold for lens molding related to the present invention.
Figure 2 is a diagram illustrating the state of the material at each stage of the manufacturing method of the injection mold for lens molding related to the present invention.
Figure 3 is a diagram showing an example of an injection mold for forming a lens manufactured by a manufacturing method related to the present invention.
Figure 4 is a diagram showing the state of the material at each stage of the method of manufacturing an injection mold for lens molding according to a conventional method compared to the present invention.

Hereinafter, the method of manufacturing an injection mold for lens molding related to the present invention and the mold manufactured thereby will be described in detail with reference to the attached drawings.

Figure 1 sequentially shows a method of manufacturing an injection mold for lens molding related to the present invention.

First, basic processing is performed on the rod-shaped material (S10). The material may be in the form of a rod made of chrome alloy stainless steel mold steel (e.g. STAVAX) suitable for injection molding of transparent lenses. Basic processing may include positions, shapes, and reference surfaces for fixing or fastening materials. Additionally, basic processing may include providing a groove-like shape on the end side (plating area) of the material so that the nickel plating layer can secure a strong bonding force to the material in the plating step described later.

Next, plating is performed on the prepared material (S20). Unlike the conventional method of performing rough processing on a material, a distinguishing feature of the present invention is that the material is directly subjected to a nickel plating process. In this process, although the lens shape has not yet been specified, full or partial plating can be performed for each group typed according to the lens shape. Plating is an electroless electroplating of nickel that involves performing a relatively time-consuming process in advance. The thickness of the plating may vary depending on the area, and may specifically be about 30 to 700 ㎛.

Heat treatment can be performed on the material for which plating has been completed to remove stress remaining in the plating structure (S30). This heat treatment may include at least one of tempering, annealing, and normalizing. Materials that have undergone heat treatment homogenize the structure of the plating layer and minimize the deterioration of surface quality during cutting. Heat treatment can be performed under various temperature conditions as needed.

The present invention is characterized by prioritizing the process of preparing the plated material, and in this state, the custom shape to be applied to the material is received (S40). At this stage, the type of lens and its spherical or aspherical shape are specified.

In this way, lens shape finishing processing is performed on the plated material according to the shape specified by order (S50). In this finishing process, a cavity and a mirror surface where the lens will be formed are formed. Finishing can be done in an environment where constant temperature can be maintained to ensure precision. Finished materials are delivered to customers after inspection.

Figure 2 is a diagram illustrating the state of the material at each stage of the manufacturing method of the injection mold for lens molding related to the present invention, and Figure 3 is an example of the injection mold for lens molding manufactured by the manufacturing method related to the present invention. This is a drawing showing.

As shown in Figure 2 (a), the material is prepared by forming grooves 11 to increase the bonding properties of the plating layer on the rod-shaped material 10.

A nickel plating layer 20 is formed on the material with the basic shape as shown in (b) of FIG. 2. The nickel plating layer 20 can be applied to the aspherical area where the lens is molded or to the entire pin core body. The plating layer 20 may be formed so that the thickness of the plating layer 21 applied to the end of the material 11 where the shape surface corresponding to the lens is located is thicker than the thickness of the plating layer 22 applied to the side of the material.

As shown in Figure 2 (c), heat treatment is performed to create a plating layer 30 in which stress in the internal structure is removed. In this state, the cavity shape corresponding to the lens is specified according to the order.

Once the target shape is determined according to the order, the specified lens shape surface 40 is formed through finishing processing, as shown in FIGS. 2(d) and 3.

According to this method, production can be completed within one day after receiving the order. In the conventional case, which takes 4 to 5 days according to the method shown in Figure 4 (in this method, basic processing of turning, heat treatment processing, and grinding processing are performed), When a custom shape is received with the material prepared, the time required can be dramatically shortened compared to the process (in which offset machining and nickel plating processing according to the custom shape are performed and then lens shape finishing processing is performed). In addition, since plating and heat treatment, which take some time, can be sufficiently performed before finishing processing, plating defects can be reduced accordingly, and as a result, the surface roughness of the processed surface of the plating layer is improved and an excellent lens surface can be obtained.

The method of manufacturing an injection mold for lens molding described above and the mold manufactured thereby are not limited to the configuration and method of the described embodiments. The above embodiments may be configured by selectively combining all or part of each embodiment so that various modifications can be made.

10: Rod material 11: Groove
20: plating layer 21: first plating layer
22: second plating layer 30: heat-treated plating layer
40: Lens shape surface

Claims (10)

Performing basic processing on a rod-shaped material to form it to have a flat upper surface;
performing nickel plating on the material;
Performing heat treatment on the plated material;
Receiving a custom shape to be applied to the plated workpiece; and
A method of manufacturing an injection mold for lens molding, comprising the step of performing lens-shaped finishing processing in the plating layer area according to a custom shape on the plating layer plated on the upper surface of the plated material to form a lens-shaped surface.
According to paragraph 1,
The step of performing basic processing of the rod-shaped material is,
A method of manufacturing an injection mold for lens molding, comprising forming a circumferential groove on a side of an end of the rod-shaped material to increase the bonding force of the plating layer.
According to paragraph 1,
The step of performing nickel plating on the material is,
A method of manufacturing an injection mold for lens molding, wherein electroless electroplating is performed on the material.
delete According to paragraph 1,
A method of manufacturing an injection mold for lens molding, wherein the heat treatment includes at least one of tempering, annealing, and normalizing.
According to paragraph 1,
In the step of performing nickel plating on the material,
A method of manufacturing an injection mold for lens molding, wherein the nickel plating has a thickness of 30 to 700 ㎛.
According to paragraph 1,
In the step of performing nickel plating on the material,
A method of manufacturing an injection mold for lens molding, wherein the area where the plating is performed is the entire body of the material.
According to paragraph 1,
In the step of performing nickel plating on the material,
A method of manufacturing an injection mold for lens molding, wherein the area where the plating is performed is an aspherical area where the lens is molded.
According to paragraph 1,
In the step of performing nickel plating on the material,
A method of manufacturing an injection mold for lens molding, wherein the thickness of the plating layer applied to the end of the material where the shape surface corresponding to the lens is located is thicker than the thickness of the plating layer to be applied to the side of the material.
A mold for forming a lens, manufactured according to any one of claims 1 to 3 and claims 5 to 9.