JP3137151U - Injection mold for optical lens manufacturing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly accurate mold extrusion structure used for manufacturing an optical lens.
A convex base includes a convex base and a concave base, and the concave base includes a molding part that is fixed and serves as a lens surface, and a flat part 351 around the molding part. A mold space Q is formed between them, and the plastic material supplied from the flow path groove 303 is molded.
The convex base penetrates the piston mold 32 through the central axis, forms a molding part 320 at the top, fits the convex inner wall to the convex inner wall via the ball shaft cover 31, and moves up and down by a support bar. A ball bearing 310 is arranged in a net shape on the ball shaft cover, and there is no gap between the piston mold and the convex inner wall, and the slide operation makes the molding operation of the molding part 320 and the extrusion operation after molding smooth and distorted. Do without.
[Selection] Figure 5

Description

The present invention relates to a mold extrusion structure used for manufacturing an optical lens. In particular, the present invention relates to a mold extrusion structure used for manufacturing an optical lens that achieves the purpose of improving bias and distortion during the manufacturing process of an optical lens by a precision imitation device applied to precision injection molding.

As shown in FIG. 1, a mold 1 of an injection molding machine generally used for an optical lens is composed of a fixed first mold 10 and a movable second mold 11.
After the second mold 11 and the first mold 10 are combined, a mold space 13 having a specific shape is formed on both opposing surfaces, and a molten liquid lens material is injected into the mold space 13, A specific pressure and temperature are maintained for a certain period of time, the surroundings are cooled to a specific temperature with water, and the first mold 10 and the second mold 11 are separated. This is a so-called “opening mold operation”, the second mold 11 is separated from the first mold 10, and the optical lens after the initial molding is temporarily placed on the second mold 11.
In the known method, a concentric shaft rod 12 is installed on the second mold 11 in the known method, and the molded optical lens is pushed out from the joint surface of the second mold 11 by the shaft rod 12 and separated. . Since the shaft rod 12 advances in the second mold 11, there is always a gap θ between the shaft rod 12 and the wall of the second mold 11. Since the second mold 11 also has a mold forming operation when matching the mold, the size of the gap θ affects the size of the deckle edge of the circumference generated after molding the optical lens at the time of mold formation. This affects the accuracy of the optical lens curvature and center point.
When a single camera lens is formed by combining a large number of lenses, the precision of the center point affects the quality of the combined camera lens as an optical axis. However, in an optical lens that is molded by injection molding using a plastic raw material, it is difficult to control the size of the lens after molding and the amount of deformation of the inner wall gap of the second mold 11 during the molding process. Manufacturing is technically very difficult. Therefore, it has not been widely adopted for a long time in the high precision optical lens region. When it was necessary to use a high precision optical camera lens, an expensive glass polished camera lens had to be used.

In the known optical camera lens manufacturing technology, a mold space is generally formed by a pair of molds corresponding to the mold, and the plastic material softened under a high temperature environment is deformed to a necessary shape, and the necessary optical after cooling. Get a camera lens.
In the “mold structure and precision mold” disclosed in the certificate number I247662 of the Chinese Patent Gazette, the mold structure is press-molded at the positions of the first molding part and the second molding part using an injection plastic raw material. Since the first mold is movable, a certain gap is still required between the first mold and the second mold to meet the different power requirements of the optical lens. When the first mold is propelled in the cylindrical mold during the injection molding process, a certain angle deviation may occur, which causes wear of the inner wall of the cylindrical mold and further creates a gap. Thus, when the first mold is propelled, the strain is inclined.
In the press of the plastic raw material, correction is performed by the heat-resistant expansion layer at the time of molding. The first mold causes a certain angle bias in the initial stage of propulsion, but the first mold center line and the second mold center line move in accordance with the expansion of the heat resistant expansion layer. When the heat-resistant expansion layer expands to fill the inner wall of the cylindrical mold, the overlap between the first mold center line and the second mold center line is corrected, and the bias phenomenon at the time of mold synthesis of the mold structure is improved. Thus, the deckle edge is reduced, and the occurrence of the optical lens surface distortion is reduced. However, there is still a certain gap (1-6 μm) between the first and second molds and the inner wall. This is a significant difference from the close contact state in which the gap of the present invention can be reduced to 0 to 0.03 μm.
JP 2007-125731 A

The problem to be solved by the present invention is to provide an optical mold extruding structure that can meet the high precision requirement at the time of optical lens production and can eliminate the bias phenomenon.

In order to solve the above-described problems, the present invention provides a mold extrusion structure used for manufacturing the following optical lens.
Consists of a convex base and a concave base,
The convex base comprises a ball shaft cover, a piston mold, a pad and a support bar,
The piston mold and the ball shaft cover integrally form a columnar shape, and are disposed in the convex trapezoidal hole so as to cover the piston mold so that the ball shaft cover is coaxial. A plurality of circular balls are held, and the one side of the ball shaft cover is in contact with the circular ball and the convex base inner wall, and the other side of the ball shaft cover is in contact with the circular ball and the piston mold peripheral wall. The molding part at one end of the piston mold and the flat part of the convex base are in contact with each other to form a molding part and a flat part corresponding to the molding part and the flat part of the concave base, respectively.
The concave base is provided with a molding part and a flat part, the molding part, the flat part and the molding part and the flat part of the convex base are opposed to form a mold space structure,
The ball shaft cover in the convex table and the piston mold surrounding wall have no tight contact and sliding and extruding operation eliminates the lens bias and distortion phenomenon that occurs during the optical lens injection molding manufacturing process, and high precision Provided is a mold extrusion structure for use in manufacturing an optical lens that achieves production of an optical lens that can reduce the number of defective products.

As described above, according to the present invention, the stable fixing of the ball shaft cover and the pushing operation without any gap eliminate the bias and distortion phenomenon of the movable piston mold axis, and the quality at the time of molding the optical camera lens is naturally improved. Since the structure is simple, it can be applied to various mold designs, the defective product rate is low, and the quality is stable, the product has high market competitiveness.

The above and other technical contents, features and functions of the present invention will be described in detail below with reference to the drawings.
As shown in FIGS. 2 and 3 which are directions of the mold extrusion structure of the present invention, the mold extrusion structure includes a convex base 30, a ball shaft cover 31, a piston mold 32, a concave base 35, a pad 33 and a support bar 34. Consists of.
Further, as shown in FIG. 5, the concave base 35 has a columnar shape, and is provided with a molding portion 350 and a flat portion 351 surrounding the molding portion 350 at one end thereof. The flat surface portion 351 is provided with a flow channel groove 303, and it is integrated with the flow channel groove 303 of the convex base 30 flat surface portion 302 so as to form a conduction path. The convex base 30 is opposed to one end surface of the concave base 35 and has a columnar shape together with the concave base 35, and a circular hole 301 is formed at the center of the flat portion 302 on the end face. A flow path groove 303 that conducts to the flat surface portion 302 is formed, and as described above, a flow path is formed in correspondence with the flow path groove 30 of the flat surface portion 351 of the concave base 35.
A piston mold 32 is installed in 301 in the convex base 30 circular hole, the piston mold 32 has a columnar shape, and a molding portion 320 is provided at one end thereof.
The molding part 320 is located in the circular hole 301 of the convex base 30, and its opposite end is connected to the pad 33 and the support bar 34 and covers the hollow cylindrical ball shaft cover 31. The ball shaft cover has a plurality of circular balls 310 arranged on its cylindrical surface and performs the same function as a bearing.
The outer periphery of the ball shaft cover 31 is in contact with the inner wall of the convex table 30 via a plurality of circular balls 310, and the inner periphery of the ball shaft cover 31 is connected to the piston mold via a plurality of circular balls 310. 32 Contact each other with the outer wall. The molding part 320 at one end of the piston mold 32 is in contact with the flat part 302 of the convex base 30 and forms a mold mold space structure relative to the molding part 350 and the flat part 351 of the concave base 35.

As shown in FIG. 4 which is a sectional view of the principle of application of the present invention, the ball shaft cover 31 has a hollow cylindrical body. The cylindrical shell 313 and the circular ball 310 are made of a wear-resistant metal alloy material, and the expansion coefficient must be larger than that of the piston mold 32, the optical lens plastic raw material M, and the convex base 30. Otherwise, when the pressure and temperature transmitted by the optical lens plastic raw material M during the molding process in the mold space are transmitted to the ball shaft cover 31, the ball shaft cover 31 is affected by heat and pressure, and expands. Therefore, it is not possible to prevent the piston mold 32 from being extended and the convex table 30 from being deformed.
In the optimum state of the present invention, the circular balls 310 are arranged in a net-like manner and are arranged tightly in the shaft hole 312 of the ball shaft cover 31 and the adjacent circular balls 310 are connected in series with the same circle center. Based on the dotted surface principle, the outer periphery of the piston mold 32 contacts each other through the circular ball 310 contact point 311 and the ball shaft cover 31, and the piston mold 32 center line A and the ball shaft cover 31 center line B are equidistant. And the two center lines are parallel to each other. The inner wall of the convex table 30 contacts the contact point 311 of the circular ball 310 through the ball shaft cover 31, and the inner wall center line C of the convex table 30 and the center line B of the ball shaft cover 31 maintain an equal distance. The two center lines are parallel to each other. The gap between the molding part 320 of the piston mold 32 and the flat part 302 of the convex base 30 is 0 to 0.03 μm, and the outer diameter of the piston mold 32 is equal to the inner diameter of the circular hole 301 of the convex base 30.
When the piston mold 32 is guided and moved in the convex base 30, the ball shaft cover 31, the inner wall of the convex base 30 and the piston mold 32 slide without gaps, and the piston mold 32 is Even when moving forward in the mold base 30 circular hole 301 to push out the optical lens, there is no gap and an accurate operation can be maintained. Thus, after molding, an accurate quality of the optical lens surface type curvature is achieved.

As shown in FIGS. 5 and 6, when the concave base 35 to be fixed to the convex base 30 is joined (at the time of molding with the mold), the flat part 302 of the convex base 30 and the molding part 320 of the piston mold 32 are Through the contact of the ball shaft cover 31, the molding part 320 of the piston mold 32 and the flat part 302 of the convex base 30 are in close contact with each other without a gap. In addition, a mold space structure is formed relative to the flat portion 351 and the molding portion 350 of the concave base 35.
The optical lens plastic raw material M is filled into the mold space through the flow channel 303, and after the optical lens plastic raw material M is cooled, the convex table 30 is operated to separate from the concave table 35 (separate the mold). And extrude). At this time, the push-out equipment (not shown) is interlocked and guided by the ball shaft cover 31 by the connection structure of the support bar 34, the pad 33 and the piston mold 32, and the piston mold 32 is guided to the convex base. Extrusion operation is performed in 30 circular holes 301. Further, the cooled optical lens plastic raw material M is extruded by the molding part 320 at the end of the piston mold 32, and a series of injection molding processes is completed.

In order to clarify the inventive step and practicality of the present invention, the following comparative analysis is performed with known techniques.
Known technology
1. In the known injection-molded structure, the mold tends to be biased and distorted, resulting in nonuniform camera lens curvature.
2. The percentage of defective optical lenses is high, and waste of materials is inevitable. Naturally, manufacturing costs are also rising significantly.
3. In the production of optical lenses with different curvatures, it is necessary to control the size of the gap between the molded parts, so the technical difficulty is high.
Advantages of the present invention:
1. The structure and operation of the ball shaft cover with no gap ensures stable and high precision from molding to extrusion operation, eliminating the bias and distortion phenomenon of the movable piston mold shaft center, and the quality when molding optical camera lenses Of course also improve.
2. The structure is simple, can be applied to various mold designs, the defective product rate is low, and the quality is stable. Therefore, the product has high market competitiveness.
The present invention improves the drawbacks of the known technical structure, can surely improve the functions and effects, and cannot be easily created by those skilled in the art. Furthermore, the present invention has novelty and inventive step.

It is sectional drawing of a general mold extrusion structure. It is a three-dimensional instruction | indication figure of this invention mold extrusion structure. It is a decomposition | disassembly instruction | indication figure of this invention mold extrusion structure. It is an application principle sectional view of the present invention mold extrusion structure. It is an instruction | indication figure of the shaping | molding operation | movement which matches the type | mold of this invention mold extrusion structure. It is an instruction diagram of the operation of separating and extruding the mold of the mold extrusion structure of the present invention.

Explanation of symbols

1 Mold
10 First mold
11 Second mold
12 axis rod
13 type space θ gap
30 Convex table
301 hole
302 Flat part
303 Flow channel
31 Ball shaft cover
310 yen ball
311 Contact point
312 shaft hole
313 Tube shell
32 Piston mold
33 pads
34 Support bar
35 Recessed table
320 Molding part
350 Molding part
351 Flat part
M Optical lens plastic raw material
Q Mold space
A center line
B center line
C center line

Claims (3)

It consists of a fixed convex base and a movable concave base,
The convex base and the concave base each have a molding part that forms a mold space and a flat part around the molding part,
The convex base is provided with a circular hole that is inserted in the axial direction in the flat part, and an end part forms the molding part in the circular hole and is fitted with a piston mold that moves forward and backward. And
Furthermore, the cylindrical ball shaft cover is placed on the piston mold and placed between the circular hole,
The ball shaft cover is configured to hold a plurality of balls in contact with the convex inner wall surface and the outer peripheral surface of the piston mold so that the piston mold can be moved forward and backward without a gap between the wall surfaces. An injection mold used for manufacturing optical lenses. The ball shaft cover is a hollow cylindrical body, and the cylindrical shell and the circular ball are made of an abrasion-resistant metal alloy material, and a gap width between the ball shaft cover and the piston mold is 0 to 0.03 microns (μm). 2. The injection mold for use in manufacturing an optical lens according to claim 1, wherein a width of a gap between the ball shaft cover and the convex base is 0 to 0.03 microns (μm). The molded part at one end of the piston mold has an arc shape in cross section, and the opposite end of the piston mold is connected to a pad and a support rod that transmits forward and backward movements, and is connected to the convex base and the concave base flat part, respectively. 2. An injection mold for use in manufacturing an optical lens according to claim 1, wherein a flow path groove is formed and the plastic material introduction path is integrally formed when both molds are combined.

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