CN118318186A

CN118318186A - Lens and method for manufacturing the same

Info

Publication number: CN118318186A
Application number: CN202280072283.3A
Authority: CN
Inventors: 高冈俊允; 樱井祐
Original assignee: Nalux Co Ltd
Current assignee: Nalux Co Ltd
Priority date: 2022-01-14
Filing date: 2022-08-24
Publication date: 2024-07-09

Abstract

A lens is composed of a core member and an outer layer covering the core member. The core member has a flange portion protruding in a direction substantially perpendicular to an optical axis of the lens, the flange portion having a1 st surface and a2 nd surface, the flange portion having a1 st protruding portion on the 1 st surface, the 2 nd protruding portion on the 2 nd surface, the 1 st protruding portion protruding substantially perpendicularly to the 1 st surface, the 1 st protruding portion being disposed along an outer periphery of the core member in a region of 0.5% or more of the outer periphery, the 2 nd protruding portion protruding substantially perpendicularly to the 2 nd surface, the 2 nd protruding portion being disposed along the outer periphery of the core member in a region of 0.5% or more of the outer periphery.

Description

Lens and method for manufacturing the same

Technical Field

The invention relates to a lens and a method for manufacturing the same.

Background

In the case of manufacturing a thick lens by injection molding, the molded lens is prone to defects such as weld marks and trapped air. Further, since the thickness of the lens is large, it takes time to cool, and deformation, sink mark, and the like are likely to occur on the surface of the lens when the lens is cooled and solidified. Accordingly, the following methods for manufacturing thick-walled lenses have been developed: a core member of a lens is manufactured in advance, the core member is held in a mold, and only an outer layer of the core member is injected into a cavity between the core member and the mold in accordance with product specifications (for example, patent document 1 and patent document 2).

However, even when the core member is held in the mold and only the outer layer of the core member is injected into the cavity between the core member and the mold, the molded lens may have defects such as weld marks and trapped air. In the case where the core member is held in the mold by the holding flange portion of the core member, stress may be generated around the molded holding flange portion.

Heretofore, a lens and a method for manufacturing the same have not been developed, which are configured to simply improve the quality of a molded lens when a core member is held in a mold and only an outer layer of the core member is injected into a cavity between the core member and the mold.

Accordingly, there is a need for a lens and a method for manufacturing the same, which are configured to simply improve the quality of a molded lens when a core member is held in a mold and only an outer layer of the core member is injected into a cavity between the core member and the mold.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 63-315216

Patent document 2: japanese patent application laid-open No. 2018-109658

Disclosure of Invention

Problems to be solved by the invention

The invention provides a lens and a manufacturing method thereof, wherein the lens comprises the following components: the quality of the molded lens is simply improved when the core member is held in the mold and only the outer layer of the core member is injected into the cavity between the core member and the mold.

Means for solving the problems

The lens according to claim 1 of the present invention is constituted by a core member and an outer layer covering the core member. The core member has a flange portion protruding in a direction substantially perpendicular to an optical axis of the lens, the flange portion having a1 st surface and a 2 nd surface, the flange portion having a1 st protruding portion on the 1 st surface, the 2 nd protruding portion on the 2 nd surface, the 1 st protruding portion protruding substantially perpendicularly to the 1 st surface, the 1 st protruding portion being disposed along an outer periphery of the core member in a region of 0.5% or more of the outer periphery, the 2 nd protruding portion protruding substantially perpendicularly to the 2 nd surface, the 2 nd protruding portion being disposed along the outer periphery of the core member in a region of 0.5% or more of the outer periphery.

In the lens of the present embodiment, when the core member is held in the mold and only the outer layer of the core member is injected into the cavity between the core member and the mold, the 1 st and 2 nd protrusions can be used to control the flow rate of the molten material flowing into the cavity, so that the defects caused by injection molding are reduced and the quality is high.

In the lens according to embodiment 1 of claim 1 of the present invention, the 1 st projection is partially overlapped with a portion of the lens corresponding to the gate, and the 2 nd projection is partially overlapped with a portion of the lens corresponding to the gate.

In the lens according to embodiment 2 of claim 1 of the present invention, the 1st projection and the 2nd projection are arranged along the outer periphery at a distance.

According to the present embodiment, when the core member is held in the mold and only the outer layer of the core member is injected into the cavity between the core member and the mold, the flow rate of the molten material flowing into the cavity is easily controlled using the 1 st and 2 nd protrusions.

In the lens according to embodiment 3 of claim 1 of the present invention, a distance between the 1 st projection and the 2 nd projection along the outer periphery is 40% or less of the outer periphery.

In the lens according to embodiment 4 of claim 1 of the present invention, the material of the core member is the same as the material of the outer layer.

In the lens according to embodiment 5 of claim 1 of the present invention, the material of the core member is different from the material of the outer layer.

The method for manufacturing a lens according to claim 2 of the present invention is a method for manufacturing a lens comprising a core member and an outer layer covering the core member. The method comprises the following steps: manufacturing a core member having a flange portion protruding in a direction substantially perpendicular to an optical axis of the lens, the flange portion having a 1 st surface and a 2 nd surface, the flange portion having a 1 st protruding portion on the 1 st surface, the 2 nd protruding portion on the 2 nd surface, the 1 st protruding portion protruding substantially perpendicularly to the 1 st surface, the 2 nd protruding portion protruding substantially perpendicularly to the 2 nd surface, the 2 nd protruding portion being disposed substantially perpendicularly to the 1 st surface in a region of 0.5% or more of the outer circumference along the outer circumference of the core member; before the core member is held in a mold and the outer layer is molded by injection molding between the mold and the core member, the relative positional relationship between the 1 st projection and the 2 nd projection and a gate or the shape of the gate is adjusted so that a material flows from the gate to the 1 st projection side and the 2 nd projection side of the flange portion appropriately; and holding the core member within the mold, the outer layer being molded between the mold and the core member by injection molding.

According to the method of manufacturing a lens of the present embodiment, when the core member is held in the mold and only the outer layer of the core member is injected into the cavity between the core member and the mold, the 1 st and 2 nd protrusions can be used to control the flow rate of the molten material flowing into the cavity, so that a lens having less defects due to injection molding and high quality can be obtained.

In the method for manufacturing a lens according to embodiment 1 of claim 2 of the present invention, an insert mold is used in the step of adjusting the relative positional relationship between the 1 st projection and the 2 nd projection and the gate or the shape of the gate.

According to the present embodiment, the relative positional relationship between the 1 st projection and the 2 nd projection and the gate or the shape of the gate can be easily adjusted using an insert mold.

Drawings

Fig. 1 is a perspective view of a lens according to an embodiment of the present invention.

Fig. 2 is a perspective view of a core component of a lens of one embodiment of the invention.

Fig. 3 is a top view of the core member.

Fig. 4 is a flowchart for explaining a method of manufacturing a lens.

Fig. 5 is a perspective view of a mold for molding a core member.

Fig. 6 is an enlarged view of a portion shown in the quadrangle of fig. 5.

Fig. 7 is a plan view of a mold for molding an outer layer, which is used when the core member is held in the mold and the outer layer is injection molded in a cavity between the core member and the mold.

Fig. 8 is a view showing a section along A-A of fig. 7.

Fig. 9 is a view showing a cross section along line B-B of fig. 7.

Fig. 10 is a view showing a section along the line C-C of fig. 7.

Fig. 11 is a view showing a section along the line D-D of fig. 7.

Fig. 12 is a view showing a section along the line E-E of fig. 7.

Fig. 13 is a perspective view showing a case where the core member is incorporated in the 2 nd portion of the mold for molding the outer layer, which corresponds to the other surface side other than the convex surface side of the lens.

Fig. 14 is an enlarged view of a portion shown in the quadrangle of fig. 13.

Fig. 15 is a view showing a gate peripheral portion of the cross section corresponding to fig. 12 of the mold for outer layer molding.

Fig. 16 is a diagram showing a portion 150 corresponding to a gate of a lens molded by using the mold for outer layer molding described with reference to fig. 13 to 15.

Fig. 17 is a perspective view showing the case where the core member is incorporated in the 2 nd portion of the mold for molding the outer layer, which corresponds to the other surface side other than the convex surface side of the lens.

Fig. 18 is an enlarged view of a portion shown in the quadrangle of fig. 17.

Fig. 19 is a view showing a gate peripheral portion of the cross section corresponding to fig. 12 of the mold for outer layer molding.

Fig. 20 is a view showing a portion of the lens molded by the mold for outer layer molding described with reference to fig. 17 to 19, which corresponds to the gate.

Fig. 21 is a view showing a cross section corresponding to fig. 12 of a gate peripheral portion of the mold for outer layer molding in the case of using a core member in which the distance between the 1 st and 2 nd protrusions of the flange 1100 is adjusted so that the effective lengths of the gate openings of the 1 st and 2 nd portions are W1 'and W2', respectively.

Fig. 22 is a view showing a portion of the lens molded by the mold for molding an outer layer described with reference to fig. 21, which corresponds to the gate.

Fig. 23 is a side view showing a case where the core member and the 2 nd portion of the outer layer forming mold are combined.

Fig. 24 is a view showing a cross section along line A1-A1 of fig. 23 in the case of combining the 2 nd portion of the mold for outer layer molding and the core member of example 1.

Fig. 25 is a view showing a cross section along line A1-A1 of fig. 23 in the case where the 2 nd portion of the outer layer molding die and the core member of example 2 are combined.

Fig. 26 is a view showing a cross section along line A1-A1 of fig. 23 in the case of combining the 2 nd portion of the mold for outer layer molding and the core member of example 3.

Fig. 27 shows the time from the start of injection of the molten material until the molten material reaches each position of the cavity in the case where injection molding is performed in a state of the gate before adjustment.

Fig. 28 shows the time from the start of injection of the molten material until the molten material reaches each position of the cavity in the case where injection molding is performed in a state of the adjusted gate.

Fig. 29 shows the generation position of the weld mark in the case where injection molding is performed in a state of the gate before adjustment.

Fig. 30 shows the generation position of the weld mark in the case where injection molding is performed in the state of the adjusted gate.

Fig. 31 shows the generation position of trapped air in the case where injection molding is performed in a state of the gate before adjustment.

Fig. 32 shows the generation position of trapped air in the case where injection molding is performed in the state of the adjusted gate.

Fig. 33 shows a stress distribution of a cross section of the core member in the case where injection molding is performed in a state of a gate before adjustment.

Fig. 34 shows a stress distribution of a cross section of the core member in the case where injection molding is performed in a state of the adjusted gate.

Fig. 35 is a plan view of a conventional mold for molding an outer layer.

Fig. 36 is a view showing a cross section along the line F-F of fig. 35.

Fig. 37 is a view showing a section along the G-G line of fig. 35.

Detailed Description

Fig. 1 is a perspective view of a lens 100 according to an embodiment of the present invention.

Fig. 2 is a perspective view of the core member 110 of the lens 100 of one embodiment of the present invention. The lens 100 is manufactured by holding the core member 110 within a mold and injection molding an outer layer in a cavity between the core member 110 and the mold. The core member 110 has a flange portion 1100, and the flange portion 1100 has protrusions 1110, 1120. The functions of the flange portion 1100 and the protruding portions 1110, 1120 will be described later. The core member 110 also has a holding flange portion 1130 for holding the core member 100 in a mold. The flange portion 1100 and the holding flange portion 1130 are formed along the outer periphery of the core member 110 so as to protrude in a direction substantially perpendicular to the optical axis of the lens.

Fig. 3 is a top view of core member 110.

Fig. 4 is a flowchart for explaining a method of manufacturing the lens 100.

In step S1010 of fig. 4, the core member 110 having the flange portion 1100 is manufactured by injection molding, the flange portion 1100 having the protrusions 1110, 1120 on both sides.

Fig. 5 is a perspective view of a core member molding die 400. Fig. 5 is a portion of a mold for molding a portion corresponding to the convex side of the lens of the core member 110 in the mold 400 for molding a core member.

Fig. 6 is an enlarged view of a portion shown in the quadrangle of fig. 5. Fig. 6 shows the gate portion of the mold. The gate portion of the mold is formed by the insert mold 210. Molten material is injected from the runner 300 into the insert mold 210. The recess 2110 of the mold is a portion for forming the protrusion 1110 of the core member 110. The position and shape of the projection 1110 can be changed by replacing the insert mold 210.

Next, a process of holding the core member 110 in the mold and injection molding the outer layer in the cavity between the core member 110 and the mold will be described.

Fig. 7 is a plan view of an outer layer molding die 500 used when the core member 110 is held in a die and an outer layer is injection molded in a cavity between the core member 110 and the die.

Fig. 8 is a view showing a section along A-A of fig. 7. The gate portion of the outer layer molding die 500 is also formed by the insert die 220. Molten material is injected from the runner 300 into the cavity 120 between the core member 110 and the mold 500 via the insert mold 220. In the present specification, the portion of the mold 500 for molding the outer layer corresponding to the convex side of the lens is referred to as a1 st portion, and the portion corresponding to the other surface side is referred to as a 2 nd portion. The molten material is divided by the flange portion 1100 into the molten material flowing into the 1 st portion of the mold 500 and the molten material flowing into the 2 nd portion of the mold 500. In the cross section shown in fig. 8, there is a protrusion 1120 on the way the molten material flows into the 2 nd portion of the mold 500.

Fig. 9 is a view showing a cross section along line B-B of fig. 7. In the cross section shown in fig. 9, there are no protrusions on the path of the molten material flowing into the 1 st and 2 nd portions of the mold 500.

Fig. 10 is a view showing a section along the line C-C of fig. 7. In the cross-section shown in fig. 10, there is a protrusion 1110 on the way the molten material flows into part 1 of the mold 500.

Fig. 11 is a view showing a section along the line D-D of fig. 7. The core member 110 can be held in the mold 500 by sandwiching the holding flange portion 1130 by the 1 st and 2 nd portions of the mold 500.

Fig. 12 is a view showing a section along the line E-E of fig. 7. The gate is located in the portion shown in the circle of fig. 12.

The upper and lower surfaces of the flange 1100 of the core member 110 have protrusions 1110 and 1120. The projection 1110 projects substantially perpendicularly from the upper surface of the flange 1100, and the projection 1120 projects substantially perpendicularly from the lower surface of the flange 1100. The protrusions 1110, 1120 are formed along the outer circumference of the core member. The protrusions 1110 and 1120 function as barriers on the paths along which the molten material flows from the gate to the 1 st and 2 nd portions of the mold 500, respectively. Accordingly, the flow rates of the molten material flowing into the 1 st portion of the mold 500 and the 2 nd portion of the mold 500, respectively, can be changed by changing the areas of the protrusions 1110, 1120 that partially close the openings of the gates.

Fig. 35 is a plan view of a conventional mold for molding an outer layer. Fig. 35 corresponds to fig. 7.

Fig. 36 is a view showing a cross section along the line F-F of fig. 35. Fig. 36 corresponds to fig. 8 to 10. In the core member of the prior art, there are no protrusions on the way the molten material flows into the 1 st part on the left and the 2 nd part on the right of the mold.

Fig. 37 is a view showing a section along the G-G line of fig. 35. Fig. 37 corresponds to fig. 11.

Next, a method of adjusting the flow rate of the molten material flowing into the 1 st part of the mold 500 and the 2 nd part of the mold 500 will be described in detail.

In step S1020 in fig. 4, before the core member 110 is held in the mold 500 and the outer layer is molded by injection molding in the cavity 120 between the mold 500 and the core member 110, the relative positional relationship between the 1 st projection 1110 and the 2 nd projection 1120 and the gate or the shape of the gate is adjusted so that the material flows from the gate to the 1 st projection 1110 side and the 2 nd projection 1120 side of the flange 1100 of the cavity 120 at an appropriate flow rate.

Fig. 13 is a perspective view showing a case where the core member 110 is incorporated in the 2 nd portion of the mold 500 for molding an outer layer, which corresponds to the other surface side other than the convex surface side of the lens.

Fig. 14 is an enlarged view of a portion shown in the quadrangle of fig. 13. Fig. 14 shows the gate portion of the mold. The gate portion of the mold is formed by the insert mold 220. Molten material is injected from the runner 300 into the cavity 120 between the core member 110 and the mold 500 via the insert mold 220. A cavity 120, which is not illustrated in fig. 14, is formed between the core member 110 and the 1 st portion of the mold 500 for outer layer molding, which corresponds to the convex side of the lens. The gate insert mold 220 has a slit (long hole) 2010, and the gate insert mold 220 is fixed to the 2 nd portion of the mold 500 by a fixing bolt 2020 in the slit 2010. The position of the gate insert mold 220 relative to the 2 nd portion of the mold 500 can be varied in the longitudinal direction of the slit 2010 by varying the fixing position of the fixing bolt 2020 within the slit 2010. Reference numeral 2030 denotes a spacer.

Fig. 15 is a view showing a gate peripheral portion of the outer layer molding die 500 in a cross section corresponding to fig. 12.

The gate peripheral portion shown in fig. 15 is a portion shown by a circle in fig. 12. In fig. 15, an opening portion of the gate is shown in hatching. The dark hatching shows the position of the opening of the gate of the 1 st part of the mold 500 for outer layer molding, and the light hatching shows the position of the opening of the gate of the 2 nd part of the mold 500 for outer layer molding. A part of the opening of the gate of the 1 st part shown in dark hatching overlaps with the 1 st projection 1110, is partially closed by the 1 st projection 1110, and a part of the opening of the gate of the 2 nd part shown in light hatching overlaps with the 2 nd projection 1120, and is partially closed by the 2 nd projection 1120. Therefore, the effective length of the opening portion of the gate of the 1 st part and the effective length of the opening portion of the gate of the 2 nd part are denoted by W1 and W2, respectively. If the width of the opening of the gate of the 1 st part and the width of the opening of the gate of the 2 nd part are the same, the ratio of the flow rate of the molten material flowing into the 1 st part of the mold 500 to the flow rate of the molten material flowing into the 2 nd part of the mold 500 is W1/W2. Here, the width of the opening means the length of the opening in the vertical direction in the drawing. The initial value of W1/W2 may be the ratio of the volume of the cavity between the core member 110 and the 1 st part of the mold to the volume of the cavity between the core member 110 and the 2 nd part of the mold.

In step S1030 of fig. 4, the core member 110 is held in the mold 500, and the outer layer is molded by injection molding in the cavity 120 between the mold 500 and the core member 110.

Fig. 16 is a diagram showing a portion 150 corresponding to a gate of the lens 100 molded by using the mold 500 for outer layer molding described with reference to fig. 13 to 15.

In step S1040 of fig. 4, it is determined whether the quality of the molded lens 100 is acceptable. Specifically, the quality of the lens 100 was evaluated based on the weld mark and the occurrence of trapped air in the molded lens. If the quality is tolerable, the process ends. If the quality is not acceptable, the process returns to step S1020 to perform necessary adjustment. Specifically, the ratio of the flow rate of the molten material flowing into the 1 st portion of the mold 500 to the flow rate of the molten material flowing into the 2 nd portion of the mold 500 is adjusted.

As an example, the adjustment in the case of increasing the ratio of the flow rate of the molten material flowing into the 1 st portion of the mold 500 to the flow rate of the molten material flowing into the 2 nd portion of the mold 500 will be described below.

Fig. 17 is a perspective view showing a case where the core member 110 is incorporated in the 2 nd portion of the mold 500 for molding an outer layer, which corresponds to the other surface side other than the convex surface side of the lens.

Fig. 18 is an enlarged view of a portion shown in the quadrangle of fig. 17. In fig. 18, the set screw 2020 is located at the right end of the slot 2010, and the gate insert mold 220 is moved to the left as much as possible with respect to the 2 nd portion of the mold 500.

Fig. 19 is a view showing a gate peripheral portion of the outer layer molding die 500 in a cross section corresponding to fig. 12.

The gate peripheral portion shown in fig. 19 is a portion shown by a circle in fig. 12. By moving the gate insert mold of the 1 st part of the mold 500 to the left with respect to the 1 st part of the mold 500, a portion of the opening of the 1 st part gate shown by the dark hatching, which is partially closed by the 1 st protrusion 1110, becomes smaller, and the effective length W1' of the opening of the 1 st part gate becomes larger than W1. Further, by moving the insert mold of the gate of the 2 nd portion of the mold 500 to the left with respect to the 2 nd portion of the mold 500, a larger portion of the opening of the gate of the 2 nd portion shown by the light shading is partially closed by the 2 nd protrusion 1120, and the effective length W2' of the opening of the gate of the 2 nd portion becomes smaller than W2. As a result, the ratio of the flow rate of the molten material flowing into the 1 st portion of the mold 500 to the flow rate of the molten material flowing into the 2 nd portion of the mold 500 can be expected to be increased by the above-described adjustment.

Fig. 20 is a diagram showing a portion 150 corresponding to a gate of the lens 100 molded by using the mold 500 for outer layer molding described with reference to fig. 17 to 19. The cross-section of the corresponding portion 150 is not rectangular, but is shaped such that the two rectangles are offset from each other along adjacent sides. The reason why the section of the portion 150 has the above-described shape is that the moving amount of the insert mold of the gate of the 1 st portion of the mold 500 is different from the moving amount of the insert mold of the gate of the 2 nd portion of the mold 500.

In the case where the above-described cross-sectional shape of the portion 150 is not preferable, the core member 110 in which the distance between the 1 st and 2 nd protruding portions of the flange 1100 is adjusted so that the effective lengths of the opening portions of the 1 st and 2 nd gates are W1 'and W2', respectively, may be molded in step S1010 without moving the insert mold of the 1 st and 2 nd gates, and step S1030 may be performed using the core member 110.

Fig. 21 is a view showing a cross section corresponding to fig. 12 of a gate peripheral portion of the mold 500 for outer layer molding in the case of using a core member in which the distance between the 1 st and 2 nd protrusions of the flange 1100 is adjusted so that the effective lengths of the gate openings of the 1 st and 2 nd portions are W1 'and W2', respectively.

Fig. 22 is a diagram showing a portion 150 corresponding to a gate of the lens 100 molded by using the mold 500 for molding an outer layer described in fig. 21.

In step S1040 of fig. 4, it is determined whether the quality of the molded lens 100 is acceptable.

In this way, in the manufacturing method of the present invention, it is possible to repeatedly perform steps S1020 to S1040 of fig. 4. Therefore, it is preferable that a plurality of core members 110 are manufactured in advance in S1010.

The 1 st projection 1110 and the 2 nd projection 1120 shown in fig. 15, 19 and 21 are arranged at intervals along the outer periphery of the core member 110. In general, the 1 st projection 1110 and the 2 nd projection 1120 may be disposed so as to partially or entirely overlap each other along the outer periphery of the core member 110. In this case, the adjustment is performed by changing the positions of the 1 st projection 1110 and the 2 nd projection 1120 along the outer periphery, respectively.

Next, an embodiment of the core member 110 will be described. The material of the core member 110 and the outer layer of the embodiment is polymethyl methacrylate. The present invention can also be applied to a case where the material of the core member 110 is different from the material of the outer layer.

Fig. 23 is a side view showing a case where the core member 110 and the 2 nd portion of the outer layer molding die 500 are combined.

Example 1

Fig. 24 is a view showing a cross section along line A1-A1 in fig. 23 in the case where the core member 110 of example 1 and the 2 nd portion of the outer layer molding die 500 are combined. In fig. 24 to 26, numerals shown near double arrows denote lengths. The unit of length is millimeters. Also, in fig. 24 to 26, the insert mold of the gate is located at the leftmost side of the adjustable range. The core member 110 of example 1 is shown in fig. 2. The length of the 2 nd protrusion 1120 of embodiment 1 along the outer circumference of the core member 110 is 4mm, and the length of the entire outer circumference of the core member 110 is 220 mm. Accordingly, the ratio of the length of the 2 nd protrusion 1120 along the outer circumference of the core member 110 to the length of the entire outer circumference of the core member 110 of embodiment 1 is 1.8%. In embodiment 1, the distance along the outer periphery of the core member 110 between the 1 st projection 1110 and the 2 nd projection 1120, which are not illustrated in fig. 24, is 4mm, and the ratio of the above-mentioned distance to the length of the entire outer periphery of the core member 110 is 1.8%. In embodiment 1, the holding flange 1130 is disposed only on the left and right side surfaces of the core member 110.

Example 2

Fig. 25 is a view showing a cross section along line A1-A1 in fig. 23 in the case where the core member 110 of example 2 and the 2 nd portion of the outer layer molding die 500 are combined. The length of the 2 nd protrusion 1120 of embodiment 2 along the outer circumference of the core member 110 is 4mm, and the length of the entire outer circumference of the core member 110 is 220 mm. Accordingly, the ratio of the length of the 2 nd protrusion 1120 along the outer circumference of the core member 110 to the length of the entire outer circumference of the core member 110 of embodiment 2 is 1.8%. In embodiment 2, the distance along the outer periphery of the core member 110 between the 1 st projection 1110 and the 2 nd projection 1120, which are not illustrated in fig. 25, is 4mm, and the ratio of the above-mentioned distance to the length of the entire outer periphery of the core member 110 is 1.8%. In embodiment 2, the holding flange portion 1130 is disposed at a portion other than the 2 nd protrusion 1120 having a length of 4mm along the outer periphery and the gate having a length of 8mm along the outer periphery of the core member 110. In other words, the 2 nd protrusion 1120 is formed continuously with the holding flange 1130.

Example 3

Fig. 26 is a view showing a cross section along line A1-A1 in fig. 23 in the case where the core member 110 of example 3 and the 2 nd portion of the outer layer molding die 500 are combined. The length of the 2 nd protrusion 1120 of embodiment 3 along the outer circumference of the core member 110 is 4mm, and the length of the entire outer circumference of the core member 110 is 220 mm. Accordingly, the ratio of the length of the 2 nd protrusion 1120 along the outer circumference of the core member 110 to the length of the entire outer circumference of the core member 110 of embodiment 3 is 1.8%. In example 3, the distance along the outer periphery of the core member 110 between the 1 st projection 1110 and the 2 nd projection 1120, which are not illustrated in fig. 26, is 4mm, and the ratio of the above-mentioned distance to the length of the entire outer periphery of the core member 110 is 1.8%. The holding flange portion 1130 of embodiment 3 is formed at a constant interval on the outer periphery of the core member 110. In example 3, the constant interval was 6 mm.

Next, effects of the present invention will be described by simulation. In the case of changing the effective length of the gate using the 1 st and 2 nd portions of the mold 500 shown in fig. 15 and others, it was found by simulation how the molten material flowed from the gate into the cavity 120. The simulation program uses Moldflow (registered trademark). The core member 110 used in the simulation was provided with the holding flange 1130 around the entire periphery other than the periphery of the gate. When simulation of the core member having the holding members of various forms is performed, the result of the simulation is hardly changed. Therefore, the shape of the retaining member does not greatly affect how the molten material flows from the gate into the cavity 120.

Table 1 is a table showing effective lengths and effective cross-sectional areas of gates of the 1 st and 2 nd portions of the mold 500 before and after the adjustment.

TABLE 1

In table 1, the effective length of the gate of the 1 st part before adjustment corresponds to W1 in fig. 15, and the effective length of the gate of the 2 nd part before adjustment corresponds to W2 in fig. 15. The effective length of the gate of the 1 st part after adjustment corresponds to W1 'of fig. 19, and the effective length of the gate of the 2 nd part after adjustment corresponds to W2' of fig. 19. Here, the effective length of the gate corresponding to the 1 st part before the adjustment of W1 is equal to the effective length of the gate corresponding to the 1 st part after the adjustment of W1'. The effective sectional area of the gates of the 1 st and 2 nd portions before adjustment was 7 square millimeters. The effective sectional area of the gate of the adjusted part 1 is 7 square millimeters, and the effective sectional area of the gate of the adjusted part 2 is 4 square millimeters.

Fig. 27 shows the time from the start of injection of the molten material until the molten material reaches each position of the cavity 120 in the case where injection molding is performed in a state of the gate before adjustment. The unit of time is seconds.

Fig. 28 shows the time from the start of injection of the molten material until the molten material reaches each position of the cavity 120 in the case where injection molding is performed in a state of the adjusted gate. The unit of time is seconds.

Fig. 29 shows the generation position of the weld mark in the case where injection molding is performed in a state of the gate before adjustment. The weld mark is a linear molding defect generated in the mold at the junction of the molten resins during injection molding.

Fig. 31 shows the generation position of trapped air in the case where injection molding is performed in a state of the gate before adjustment. The trapped air is a phenomenon in which air bubbles are taken in by the resin flowing in from a plurality of directions and generated in the molded article.

Fig. 33 shows a stress distribution of a cross section of the core member 110 in the case where injection molding is performed in a state of a gate before adjustment. The unit of stress is megapascals.

Fig. 34 shows a stress distribution of a cross section of the core member 110 in the case where injection molding is performed in a state of the adjusted gate. The unit of stress is megapascals.

Referring to fig. 27, in the case where injection molding is performed with the gate before adjustment, the height to which the molten material flowing from the gate on the lower side into the cavity 120 of the 2 nd portion on the lower side of the mold 500 reaches is about 1/2 of the height of the core member 110. Therefore, when injection molding is performed with the gate before adjustment, as shown in fig. 29, weld marks are formed in a wide range of the cavity 120 of the 1 st portion of the mold 500. When injection molding is performed with the gate being adjusted, trapped air is generated in the cavity 120 of the 1 st part of the mold 500 as shown in fig. 31. When injection molding is performed with the gate before adjustment, a relatively large stress is generated in the vicinity of the holding flange 1130 of the core member 110 as shown in fig. 33. The reason for this is presumed as follows. When injection molding is performed with the gate being adjusted, the molten material fills the cavity 120 of the portion 2 on the lower side of the mold 500 earlier than the cavity 120 of the portion 1 on the upper side of the mold 500. Therefore, the pressure of the 2 nd portion of the lower side of the die 500 is higher than the pressure of the 1 st portion of the upper side, and the pressure is generated from the bottom to the top, and as a result, a relatively large stress is generated in the vicinity of the holding flange portion 1130 of the core member 110.

By adjustment, the effective cross-sectional area of the gate on the underside of the mold 500 is reduced from 7 square millimeters to 4 square millimeters. Accordingly, the flow rate of the molten material flowing from the gate on the lower side of the mold 500 into the cavity 120 of the 2 nd portion on the lower side of the mold 500 decreases.

Referring to fig. 28, in the case where injection molding is performed with the gate adjusted, the height to which the molten material flowing from the gate on the lower side into the cavity 120 of the 2 nd portion on the lower side of the mold 500 reaches is about 1/5 of the height of the core member 110. Therefore, when injection molding is performed with the gate adjusted, as shown in fig. 30, weld marks are formed only in the vicinity of the boundary between the 1 st part and the 2 nd part of the mold 500. Therefore, the weld mark has little influence on the optical surface of the optical component 100. When injection molding is performed with the gate adjusted, the number of trapped air is smaller than that before adjustment shown in fig. 31, and the generation position is limited to the flange portion of the optical member 100, as shown in fig. 32. Thus, the trapped air has no effect on the optical surface of the optical component 100. When injection molding is performed with the gate adjusted, the molten material is substantially simultaneously filled in the cavity 120 of the 1 st part on the upper side of the mold 500 and the cavity 120 of the 2 nd part on the lower side of the mold 500. Therefore, the case where the pressure is generated from the bottom to the top by the pressure of the 2 nd portion on the lower side of the die 500 being higher than the pressure of the 1 st portion on the upper side does not occur, and the pressure generated in the vicinity of the holding flange portion 1130 of the core member 110 is smaller than that in fig. 33 as shown in fig. 34.

Thus, by manufacturing a lens using the core member of the present invention, a lens having high optical performance can be obtained.

The present invention can also be applied to a case where the material of the core member 110 is different from the material of the outer layer.

Claims

1. A lens comprising a core member and an outer layer covering the core member, wherein,

The core member has a flange portion protruding in a direction substantially perpendicular to an optical axis of the lens, the flange portion having a1 st surface and a2 nd surface, the flange portion having a1 st protruding portion on the 1 st surface, the 2 nd protruding portion on the 2 nd surface, the 1 st protruding portion protruding substantially perpendicularly to the 1 st surface, the 1 st protruding portion being disposed along an outer periphery of the core member in a region of 0.5% or more of the outer periphery, the 2 nd protruding portion protruding substantially perpendicularly to the 2 nd surface, the 2 nd protruding portion being disposed along the outer periphery of the core member in a region of 0.5% or more of the outer periphery.

2. The lens of claim 1, wherein,

The lens is configured such that the 1 st projection partially overlaps with a portion of the lens corresponding to the gate, and such that the 2 nd projection partially overlaps with a portion of the lens corresponding to the gate.

3. The lens of claim 1, wherein,

The 1 st projection and the 2 nd projection are arranged along the outer periphery at intervals.

4. The lens of claim 3, wherein,

The distance between the 1 st projection and the 2 nd projection along the outer periphery is 40% or less of the outer periphery.

5. The lens of claim 1, wherein,

The material of the core element is the same as the material of the outer layer.

6. The lens of claim 1, wherein,

The core member is of a material different from the material of the outer layer.

7. The lens of claim 1, wherein,

The lens has a holding flange portion protruding in a direction substantially perpendicular to an optical axis of the lens, in addition to the flange portion.

8. The lens of claim 1, wherein,

The 1 st projection or the 2 nd projection is formed continuously with the holding flange portion.

9. A method for manufacturing a lens comprising a core member and an outer layer covering the core member, wherein,

The manufacturing method of the lens comprises the following steps:

Manufacturing a core member having a flange portion protruding in a direction substantially perpendicular to an optical axis of the lens, the flange portion having a1 st surface and a2 nd surface, the flange portion having a1 st protruding portion on the 1 st surface, the 2 nd protruding portion on the 2 nd surface, the 1 st protruding portion protruding substantially perpendicularly to the 1 st surface, the 2 nd protruding portion protruding substantially perpendicularly to the 2 nd surface, the 2 nd protruding portion being disposed substantially perpendicularly to the 1 st surface in a region of 0.5% or more of the outer circumference along the outer circumference of the core member;

Before the core member is held in a mold and the outer layer is molded by injection molding between the mold and the core member, the relative positional relationship between the 1 st projection and the 2 nd projection and a gate or the shape of the gate is adjusted so that a material flows from the gate to the 1 st projection side and the 2 nd projection side of the flange portion appropriately; and

The core member is held within the mold, and the outer layer is molded between the mold and the core member by injection molding.

10. The method for manufacturing a lens according to claim 9,

In the step of adjusting the relative positional relationship of the 1 st projection and the 2 nd projection with the gate or the shape of the gate, an insert mold is used.