JP2016215531A - Method for molding optical member, molding device, and optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for molding an optical member in a short molding cycle without enlarging molding equipment, and a molding device.SOLUTION: Provided is a method for molding an optical member with a cavity C divided with a molded pair of dies, in which the cavity C is divided to a closing direction with a core 40 whose part is held in the division faces 21, 31 of each die, primary molding is performed with division cavities C1, C2, and with a new cavity C3 formed by the discharge of the core 40, secondary molding (lamination molding) is performed. It is finished by all the seven steps of core insertion→die closing→injection molding→die opening (core discharging)→die closing→injection molding→die opening (molded part discharging), and the molding cycles are short.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a molding method, a molding apparatus, and an optical member molded by the method for molding an optical member such as a projection convex lens.

  Patent Document 1 below discloses a conventional technique for a projection convex lens lamination molding method such as LED lighting, a molding apparatus, and an optical member (convex lens) molded by the method.

  Specifically, in Patent Document 1, eight molding surfaces that define cavities are equally spaced in the circumferential direction on each of the opposing divided surfaces of a pair of left and right molds (movable side and fixed side) that can move toward and away from each other. A rotary multilayer molding apparatus is described in which an injection molding is performed while intermittently rotating a movable mold around a horizontal rotation axis by a rotational drive mechanism.

  That is, the eight molding surfaces of the movable mold are all formed into the same concave spherical surface, while the eight molding surfaces of the fixed mold are from the first position where the curvature of the convex spherical surface is the largest. The curvature of the convex spherical surface gradually decreases as it moves toward the rotating side of the movable mold (→ second position → third position...). In addition, the resin layer formed in each cavity is configured to remain on the movable mold (molding surface) which is opened.

  For this reason, by repeating a series of operations of rotating the movable mold by a predetermined angle (for example, 45 degrees), closing the mold, injection molding, and opening the mold, the resin in the cavity becomes closer to the rotation side. The number of layers increases, and in the final cavity at the eighth position, a resin convex lens in which eight resin layers are laminated is molded.

WO 2012/111381 (paragraphs 0030 to 0034, FIGS. 1 to 4)

  However, in the above-mentioned Patent Document 1, a structure is provided in which cavities are provided at eight positions around the horizontal rotation axis of the pair of left and right molds (movable side and fixed mold side). First, the molding equipment is large.

  Second, in order to mold a resin convex lens, it is necessary to repeat a series of steps of mold closing, injection, pressure holding, mold opening, and movable side mold rotation a plurality of times (for example, 8 times). The time required for the apparatus to mold one convex lens, the so-called molding cycle, is long.

  The present invention has been made in view of the above-mentioned problems of the prior art, and its object is to form an optical member with a short molding cycle, a molding apparatus, and the same method without increasing the molding equipment. Another object is to provide an optical member.

In order to solve the above-mentioned problem, the invention according to claim 1 is a method for molding an optical member in which a cavity defined by a pair of molds to be closed is filled with a resin and molded.
A primary molding step of dividing the cavity in the mold closing direction of the mold by a core partly sandwiched between the divided surfaces of the mold, and injecting and molding a resin into each divided cavity;
The mold is opened so that the first resin layer, which is a primary molded body, is attached to one of the molds, and the second resin layer, which is the primary molded body, and the core are attached to the other, and the core is taken out. Child removal process;
A secondary molding step of closing the mold again and injecting and molding the resin into a new cavity formed between the first and second resin layers and corresponding to the volume of the core. It is characterized by that.

In order to solve the above-mentioned problem, the invention according to claim 5 includes the pair of the closed molds, each including a fixed mold and a movable mold movable in an approaching / separating direction with respect to the fixed mold. In an optical member molding apparatus for injecting and molding resin into a cavity defined by a mold,
A removable core that is partly sandwiched between the mold split surfaces and splits the cavity in the mold closing direction of the mold;
A primary molding cavity is constituted by a pair of split cavities defined by the mold and the core,
After the primary molding, the mold is opened so that the first resin layer, which is the primary molded body, is attached to one of the molds, and the second resin layer, which is the primary molded body, and the core are attached to the other. A secondary molding cavity is formed by a new cavity corresponding to the volume of the core formed between the first and second resin layers by closing the mold again after taking out the core. And

(Operation of Invention of Claim 1 or Invention of Claim 5)
In the prior art, it is necessary to repeat a series of steps of mold closing → injection → holding pressure (molding) → mold opening → rotation a number of times corresponding to the number of resin layers to be laminated. Although "insertion" and "core removal" are newly added, the series of steps of mold closing → injection → pressure holding (molding) → mold opening is less than the number of resin layers to be laminated (primary molding) And secondary molding 2) only, and the molding cycle is shortened.

  For example, in order to mold a laminated molded body (optical member) consisting of three layers, in the conventional technique, the five steps of mold closing → injection → holding pressure (molding) → mold opening → rotation are repeated three times for a total of 15 steps. In contrast, in the present invention, although two steps of “core insertion” and “core removal” are added, a series of steps of mold closing → injection → pressure holding (molding) → mold opening is performed twice. (Primary molding and secondary molding) It only needs to be repeated. That is, all 10 steps from core insertion → mold closing → injection → pressure holding (primary molding) → mold opening → core removal → mold closing → injection → pressure holding (secondary molding) → mold opening are all necessary. It is clear that the molding cycle is shorter than in the prior art.

  Further, in the present invention, the optical member molding apparatus includes a pair of molds capable of closing and opening the mold, and at least a part of which is sandwiched between the mold dividing surfaces, and the cavity is divided in the mold closing direction. In addition, since it is composed of a removable core, the structure of the apparatus is simple and compact.

  In particular, since the core is exposed to the split surface of the mold that has been opened after the primary molding, the core can be easily taken out, contributing to shortening the molding cycle.

  According to a second aspect of the present invention, in the first aspect of the present invention, a groove formed along the dividing surface of the mold and engaged with a part of the core is secondarily formed in the new cavity. It is characterized in that it is used as a runner that guides resin.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, a runner for guiding a secondary molding resin to the new cavity is provided on the split surface of the mold, and the runner includes the core It functions as a groove | channel which a part of engages.

(Operation of Invention of Claim 2 or Invention of Claim 6)
Since the core is positioned relative to the cavity by engaging a part of the core sandwiched between the mold split surfaces with a groove provided along the mold split surface, the core mold Easy assembly.

  In addition, since the groove formed in the mold and engaged with a part of the core is used as a runner for guiding the secondary molding resin to a new cavity, it is easy and simple to form the runner in the mold.

The invention according to claim 3 is the invention according to claim 2, wherein a handle that engages with the groove is formed on the core, and at least a part of a peripheral edge portion of the core is provided with the handle. A flange portion is formed that is sandwiched between the split surfaces of the mold,
Primary molding is performed in such a manner that the dividing surface of the mold sandwiches at least a part of the flange portion and the handle.

  The invention according to claim 4 is characterized in that, in the invention according to claim 3, primary molding is performed in a form in which the dividing surface of the mold sandwiches at least the periphery of the flange portion.

(Operation of the invention according to claims 3 and 4)
In the first and second aspects, the core is held at a position where the cavity is divided in the mold closing direction by sandwiching a handle which is a part of the core between the dividing surfaces of the mold. The core that extends in a cantilever shape vibrates, bends, or deforms due to the pressure of the primary molding resin that is injected and filled into the split cavities. May occur. However, in claims 3 and 4, the core in the primary molding is configured such that at least a part of the flange part formed on at least a part of the peripheral part of the core is also sandwiched by the dividing surface of the mold, and the cavity is formed. A pair of resins that are primary molded bodies of a predetermined shape that have a surface shape that follows the molding surface of the mold and that have no sink marks or shape defects because vibration, bending, and deformation are suppressed because they are fixedly held at predetermined positions that are divided into two. A layer is formed with split cavities.

The invention according to claim 7 is an optical member molded by the method according to any one of claims 1 to 4,
The optical member is formed of a secondary molded body in which a third resin layer that is post-fired is laminated between first and second resin layers that are primary molded bodies that are pre-fired.

  (Operation of Invention According to Claim 7) In the optical member molded by the conventional method, the cooling rate of the resin layer that is post-applied in the cavity is in contact with the side that contacts the mold and the resin layer that is pre-applied There is a possibility that thermal sink marks may be generated in the resin layer that has been post-bonded. However, in the invention according to claim 7, the post-strike third resin layer is laminated and integrated between the pre-strike first and second resin layers, and the cooling rate of the third resin layer is Since it is almost the same (no difference) at the interface with the first and second resin layers, no thermal sink occurs in the third resin layer.

  As is apparent from the above description, the optical member molding method and molding apparatus according to the present invention can provide an optical member molding method and molding apparatus having a short molding cycle without increasing the molding equipment.

  According to the second and sixth aspects of the invention, the molding cycle can be further shortened as much as the assembly of the core to the mold becomes easier.

  In addition, since the formation of the runner in the mold is easy and simple, the structure of the molding apparatus is simplified accordingly.

  According to the third and fourth aspects of the invention, during the primary molding, the core is securely fixed and held at a predetermined position that divides the cavity into two, so that it is a primary molded body having a predetermined shape with no sink marks or shape defects. A pair of resin layers are formed by the divided cavities.

  According to the seventh aspect of the present invention, since heat sink does not occur when the optical member is molded, an optical member having excellent quality can be provided.

It is sectional drawing which shows the outline | summary of the shaping | molding apparatus of the projection convex lens which is the 1st Example of this invention. (A) is a front perspective view of a core, (b) is a rear perspective view showing an enlarged side gate forming groove formed in the peripheral edge of the flange of the core. It is a front view (figure directly opposite to a molding surface) of a movable mold. It is a front view (figure which faces a molding surface) of a fixed side metal mold | die. 3A is a longitudinal sectional view of the main part of the mold, FIG. 3A is a longitudinal sectional view of the main part of the mold along the line AA in FIG. 3, and FIG. It is a longitudinal cross-sectional view. It is a principal part longitudinal cross-sectional view of the metal mold | die which took out the core after primary shaping | molding and closed the mold again. It is a principal part enlarged front view of a movable side metal mold | die. FIG. 8 is an enlarged vertical cross-sectional view of a main part of the mold (a cross-sectional view of the mold taken along line VIII-VIII shown in FIG. 7). It is a principal part longitudinal cross-sectional view of the metal mold | die which shows a primary shaping | molding process. It is a principal part longitudinal cross-sectional view of the metal mold | die which shows a mold opening process. It is a principal part longitudinal cross-sectional view of the metal mold | die which shows a core taking-out process. It is a principal part longitudinal cross-sectional view of the metal mold | die which shows a secondary shaping | molding process. FIG. 5 is a rear perspective view of the projection convex lens in a state where the projection convex lens is formed and taken out from the mold. It is a longitudinal cross-sectional view of the projection convex lens. It is a principal part expanded longitudinal cross-sectional view (sectional view corresponding to FIG. 8) of the metal mold | die of the shaping | molding apparatus of the projection convex lens which is the 2nd Example of this invention. It is a principal part longitudinal cross-sectional view of the metal mold | die in the runner formation groove | channel position formed in the division | segmentation surface of a stationary-side metal mold (cross-sectional view corresponding to FIG.5 (b)). It is a longitudinal cross-sectional view of the projection convex lens shape | molded by the same shaping | molding apparatus (cross-sectional view corresponding to FIG. 14). It is a principal part expanded longitudinal cross-sectional view (cross-sectional view corresponding to FIG. 8) of the metal mold | die of the shaping | molding apparatus of the projection convex lens which is the 3rd Example of this invention. It is a principal part longitudinal cross-sectional view of the metal mold | die in the runner formation groove | channel position formed in the division | segmentation surface of a stationary-side metal mold (cross-sectional view corresponding to FIG.5 (b)). It is a perspective view which shows the side gate formation groove | channel provided in the division surface of a movable side metal mold | die. It is a longitudinal cross-sectional view of the projection convex lens shape | molded by the same shaping | molding apparatus (cross-sectional view corresponding to FIG. 14). It is a front view (figure corresponding to FIG. 3) of the movable side metal mold | die which is the principal part of the shaping | molding apparatus of the projection convex lens which is the other Example of this invention. It is a front view (figure corresponding to Drawing 4) of the fixed side metallic mold which is the principal part of the forming device. It is a front view of a core unit. It is a front view of the projection convex lens shape | molded by the shaping | molding apparatus of the projection convex lens which is another Example of this invention. It is a right view of the projection convex lens. FIG. 26 is a horizontal sectional view of the projection convex lens (a sectional view taken along line XXVII-XXVII shown in FIG. 25). It is a longitudinal cross-sectional view (cross-sectional view which follows the line XXVIII-XXVIII shown in FIG. 25) of the projection convex lens.

  FIGS. 1-14 shows the 1st Example which applied the shaping | molding method and shaping | molding apparatus of the optical member based on this invention to the shaping | molding method and shaping | molding apparatus of a projection convex lens.

  In FIG. 1, a molding apparatus 10 that molds a projection convex lens mainly includes a fixed mold 20 having a molding surface 22 and a molding surface 32 that faces the molding surface 22, and approaches and separates from the fixed mold 20. The movable mold 30 that can move in the direction (left and right in FIG. 1), the mold closing / opening mechanism 70 that moves the movable mold 30, and the split surfaces 21 and 31 of the molds 20 and 30 that are closed. A removable core 40 is sandwiched between the cavity 42 defined by the molding surfaces 22 and 32 in the mold closing direction. (See FIG. 2) and split cavities divided by the core 40, that is, primary molding cavities C1 and C2 defined by the molding surfaces 22 and 32 and the core 40 (FIGS. 5A and 5B). Supply primary molding resin to the An injection machine that supplies a secondary molding resin to a new cavity corresponding to the volume of the core 40, that is, a secondary molding cavity C3 (see FIG. 6) formed by taking out the core 40 after the molding process. 60. Note that the mold closing / opening mechanism 70 for moving the movable mold 30 is a known drive mechanism such as a hydraulic cylinder mechanism or a toggle mechanism.

  As shown in FIGS. 1, 3, 4, and 5, three runners 24, 34, and 36 extending radially outward from the cavity C are formed on the divided surfaces 21 and 31 of the closed molds 20 and 30. Is provided. The runners 24 and 34 communicate with the split cavities (primary molding cavities) C1 and C2 through the side gates 25 and 35, and the runner 36 has a new cavity (secondary molding cavities) C3 through the side gate 37. Communicating with

  As shown in FIGS. 1 and 4, three hot runners 26 communicating with the runners 24, 34, and 36 via the valve gate 27 are arranged in parallel on the fixed side mold 20, respectively. The raw material (transparent resin) of the convex lens 2 (see FIGS. 13 and 14) to be molded is supplied to the nozzle 26 in a molten state.

  As shown in FIGS. 1 and 6, a runner 36 that guides the secondary molding resin to the secondary molding cavity C3 will be described in detail later, but the runner formed on the split surface 31 of the movable mold 30 will be described later. The formation groove 36 a and the dividing surface 21 of the fixed mold 20 are configured. And the runner formation groove | channel 36a which the handle | steering-wheel 42 (refer FIG. 2) of the core 40 can engage with the division | segmentation surface 21 of the metal mold | die 20 is a groove | channel (FIG. 5) which clamps the core 40 (handle 42). (See (a) and (b)).

  Hereinafter, the structures of the molds 20 and 30 and the core 40 will be described in detail with reference to FIGS.

  The split surface 21 of the fixed mold 20 is provided with a molding surface 22 constituted by a concave concave plane 22 a that is slightly recessed with respect to the split surface 21 as viewed from the front, while the split surface 31 of the movable mold 30 is provided. The molding surface 32 provided on the front surface is a concave concave spherical surface 32a that is largely recessed with respect to the dividing surface 31, and a circle slightly recessed with respect to the dividing surface 31 that is formed on the opening side peripheral portion of the concave spherical surface 32a. It is composed of an annular concave flat surface 32b. Then, the molding surfaces 22 and 32 of the molds 20 and 30 that are closed are formed with a cavity C (see FIG. 1) having a shape corresponding to the projection convex lens 2 (see FIGS. 13 and 14) to be molded by the molding apparatus 10. It is configured to define.

  Further, as shown in FIG. 3, the dividing surface 31 of the movable mold 30 has a cross-section arc-shaped runner extending radially outward from the circular molding surface 32 through the side gate forming grooves 35a and 37a. Forming grooves 34a and 36a are provided, and the dividing surface 21 of the stationary mold 20 also extends outward in the radial direction from the circular molding surface 22 through the side gate forming groove 25a as shown in FIG. A runner forming groove 24a having an arcuate cross section is provided. By closing the molds 20 and 30, the resin for primary molding is formed by the runner forming grooves 34a and 36a and the dividing surface 21, as shown in FIGS. The runners 34 and 36 for supplying the secondary molding resin are formed, and the runner 24 for supplying the secondary molding resin is formed by the runner forming grooves 24 a and the dividing surface 31. The runners 24, 34, 36 (runner forming grooves 24a, 34a, 36a) extending radially outward from the cavity C extend in a radial direction of 120 degrees in the circumferential direction from the cavity C, as shown in FIGS. ing.

  On the other hand, as shown in FIG. 2, the core 40 has a structure in which one rod-shaped handle 42 extends radially outward from the peripheral portion of the disk-shaped core main body 41. It is composed of the same material (metal having excellent heat transfer properties) as the constituent material.

  The core body 41 has an annular shape with a thickness matching the depth of the annular concave flat surface 32b on the outer periphery of the arcuate central region 41a having a vertical cross-sectional arc shape smaller than the curvature of the concave spherical surface 32a of the molding surface 32. As shown in FIG. 5, the flange portion 41 b has a structure in which the flange portion 41 b is integrally formed, and can be engaged with a cavity C defined by the molding surfaces 22 and 32 of the molds 20 and 30 that are closed (outer diameter). And the cavity C can be divided into two at approximately equal intervals in the mold closing direction.

  Further, as shown in FIGS. 2, 5 (a) and 8, side gates provided on the dividing surface 31 of the mold 30 are formed at predetermined positions on the outer peripheral edge of the annular flange 41 b of the core body 41. In cooperation with the groove 35a, an L-shaped side gate formation groove 41b1 is formed which communicates the runner formation groove 34a with the split cavity C2. In other words, the primary molding resin guided to the runner 34 via the valve gate 27 during the primary molding performed in the form in which the cavity C is divided by the core 40 is constituted by the side gate forming grooves 35a and 41b1 that communicate with each other. Injected into the split cavity C2 through the side gate 35.

  The core body 41 is in a cavity C formed by the closed molds 20 and 30, and in the case of primary molding, the split cavities C1 and C2 are defined in cooperation with the molding surfaces 22 and 32. In addition, a new cavity for secondary molding, that is, a new cavity C3 (see FIG. 6) sandwiched between the first and second resin layers 2-1 and 2-2, which are primary molded bodies, is set. It is also a member. Therefore, the central region 41a of the core body 41 is configured to have a smooth curved surface shape so that the molten resin injected into the divided cavities C1 and C2 and the new cavity C3 can smoothly flow and be filled. ing.

  On the other hand, the handle 42 of the core 40 is formed in a size that can be engaged with the runner forming groove 36a formed along the dividing surface 31 of the mold 30 without rattling. That is, the cross-sectional shape of the handle 42 matches the cross-sectional shape of the runner forming groove 36a.

  For this reason, when the core 40 is assembled to the dividing surface 31 of the mold 30, the core body 41 is engaged with the opening side of the molding surface 32 by assembling the handle 42 so as to coincide with the runner forming groove 36a. The side gate formation groove 41 b 1 formed on the outer peripheral edge of the core body 41 exactly coincides with the side gate formation groove 35 a formed on the dividing surface 31 of the movable mold 30. That is, the handle 42 of the core 40 and the runner formation groove 36a provided on the dividing surface 31 constitute positioning means for positioning the core body 41 in the circumferential direction with respect to the molding surface 32 constituting the cavity C.

  Further, the core 40 in the primary molding step has its handle 42 sandwiched between the runner forming groove 36 a and the dividing surface 21 of the mold 20, and the entire annular flange portion 41 b is a circle near the periphery of the molding surface 32. It is clamped between the annular concave flat surface 32b and the dividing surface 21 of the mold 20, and is securely fixed and held so that the core 40 does not vibrate or deform during the primary molding process (see FIG. 8).

  Specifically, the core 40 has a structure in which only the handle 42 is sandwiched between the runner forming groove 36 a and the dividing surface 21 of the mold 20, and the core body 41 extends in a cantilever manner into the cavity C. However, the core body 41 is vibrated, bent or deformed by the pressure of the primary molding resin injected and filled into the divided cavities C1 and C2, and the resin layer 2- There is a risk of sink marks and shape defects in 1 and 2-2.

  However, in this embodiment, in addition to the handle 42 of the core 40 being sandwiched between the runner forming groove 36 a and the dividing surface 21 of the mold 20, the entire flange portion 41 b of the core body 41 is a circle of the mold 30. Since it is sandwiched between the annular concave flat surface 32b and the dividing surface 21 of the mold 20, vibrations, flexures and deformations that may occur in the core body 41 during primary molding are reliably suppressed. As a result, a pair of resin layers 2-1 and 2-2, which are primary molded bodies having a predetermined shape and having a surface shape that follows the molding surfaces 22 and 32, without sink marks or shape defects, are molded by the divided cavities C1 and C2. (See FIG. 9).

  In particular, the split cavities (primary molding cavities) C1 and C2 are defined by the molds 20 and 30 and the core 40 having excellent thermal conductivity, so that one molding surface of the cavity is formed of a resin layer. Compared with the prior art document 1, the time required for the resin layers 2-1 and 2-2 filled in the divided cavities C1 and C2 to cool and solidify is short. The shorter the time, the shorter the molding cycle of the molding apparatus 10 is.

  Further, as shown in FIGS. 7 and 8, on the annular concave flat surface 32b near the outer periphery of the molding surface 32 of the movable die 30, there are provided core ejecting pins 50 that can project into the split cavity C2 in the circumferential direction. The core protruding pins 50 are provided at eight locations, and the core protruding pins 50 are formed by removing only the core 40 while the resin layer 2-2 as the primary molded body is left in the mold 30 from the mold 30 that has been opened after the primary molding. Used for removal (see FIG. 11). The core protrusion pin 50 also functions as a knockout pin when taking out the molded product (convex lens 2) that is secondarily molded from the mold 30.

  That is, when the molds 20 and 30 are opened after the resin layers 2-1 and 2-2 are primarily formed by the divided cavities C1 and C2, the molds 20 and 30 are separated from each other as shown in FIG. 31, the fixed mold 20 has a step portion between the dividing surface 21 and the molding surface 22 (concave surface 22 a), and further, a runner forming groove 24 a is formed on the dividing surface 21. Therefore, the resin layer 2-1 that is the primary molded body is held in a form in close contact with the molding surface 22. In particular, the core body 41 has a roughened surface and is easily peeled off from the resin layers 2-1 and 2-2. Specifically, the adhesion between the core body 41 and the resin layers 2-1 and 2-2 as the primary molded body is greatly influenced by the adsorption force due to the vacuum state at the interface. Then, by roughening the surface of the core body 41, air enters the interface at the timing when the core body 41 is about to peel off from the resin layers 2-1 and 2-2, and the resin layer 2-1 , 2-2 decreases, and the core body 41 is easily peeled off from the resin layers 2-1, 2-2.

  In order to make the core body 41 easy to peel off from the resin layers 2-1, 2-2, instead of the surface roughening treatment described above, a well-known surface treatment (for example, a hook) that improves the releasability to the resin is used. (Chemical material layer, ceramic layer, metal compound layer, etc.) may be applied to the core body 41, or the two may be combined.

  For this reason, the resin layer 2-1 is securely held in close contact with the molding surface 22 of the fixed-side mold 20 when the mold is opened. On the other hand, in the movable mold 30, the other resin layer 2-2 which is a primary molded body is held in a form in close contact with the molding surface 32, and the core body 41 is also in a form in close contact with the resin layer 2-2. Retained.

  As described above, the resin layer 2-2 and the core body 41, which are primary molded bodies, are laminated on the molding surface 32 of the movable mold 30 that has been opened, as shown by the arrows in FIG. The core protruding pin 50 pushes and presses the flange portion 41b of the core main body 41, so that the core main body 41 is smoothly separated from the resin layer 2-2 and is in close contact with the molding surface 32. 2 is separated in a direction in which the entire core 40 including the core body 41 is separated (see FIG. 11).

  FIG. 6 is a vertical cross-sectional view of the main parts of the molds 20 and 30 in which the core 40 is taken out from the mold 30 opened after the primary molding and then closed again. A new cavity C3 corresponding to the volume of the core 40 taken out is formed inside the molds 20 and 30 which are closed, and a runner 36 provided on the dividing surfaces 21 and 31 of the molds 20 and 30 is formed. The secondary molding resin is injected into the cavity C3 through the gate 37.

  Next, the process of shape | molding the projection convex lens 2 using the shaping | molding apparatus 10 is demonstrated with reference to FIG.

  First, after assembling the core 40 at a predetermined position of the split surface 31 of the movable mold 30 opened with respect to the fixed mold 20, the movable mold 30 is moved in a direction approaching the fixed mold 20. Then, the molds are closed to form the divided cavities C1 and C2 (see FIGS. 5A and 5B).

  Next, as shown in FIG. 9, a primary molding step of molding the resin layers 2-1 and 2-2 as primary molded bodies by simultaneously injecting molten resin into the divided cavities C1 and C2 and holding the pressure for a predetermined time. Do.

  Next, as shown in FIG. 10, when mold opening is performed to move the movable mold 30 away from the fixed mold 20, the first resin layer 2-1 that is the primary molded body is fixed. The second resin layer and the core 40, which are primary molded bodies, are held on the side mold 20 in a form attached to the movable side mold 30, respectively. Then, as shown in FIG. 11, the core protrusion pin 50 (see FIGS. 7 and 8) is driven to take out only the core 40 from the mold 30.

  Next, when the movable side mold 30 is moved in the direction approaching the fixed side mold 20 and the mold is closed again as shown in FIG. 6, the first and second primary molded bodies are formed in the cavity C. A new cavity C3 corresponding to the volume of the core 40 (core body 41) sandwiched between the resin layers 2-1 and 2-2 is formed.

  Next, as shown in FIG. 12, a secondary molding step of injecting and molding molten resin into a new cavity C3 through the runner 36 is performed, and the resin layers 2-1 and 2- that are the primary molded bodies that have been preliminarily formed are performed. A projection convex lens 2 which is a secondary molded body obtained by laminating and integrating a resin layer 2-3 post-stripped between the two is molded (see FIG. 12).

  Finally, after performing a mold opening process in which the movable mold 30 is moved away from the fixed mold 20, the core protrusion pin 50 (see FIGS. 7 and 8) is driven to form from the mold 30. The projection convex lens 2 is removed.

  FIG. 13 shows the projection convex lens 2 taken out from the mold 30. Since rod-shaped resin molded bodies 3, 4, and 5 cooled and solidified in the runners 24, 34, and 36 are radially extended on the outer periphery of the projection convex lens 2, these resin molded bodies 3, 4 are provided in a later process. , 5 at the base position (branch position with the projection convex lens 2), the predetermined projection convex lens 2 (see FIG. 14) is completed.

  In the convex lens molded by the method of the prior patent document 1, the cooling rate of the resin layer post-applied in the cavity is greatly different between the side in contact with the mold and the side in contact with the pre-applied resin layer. Heat sink may occur in the layer. However, in the convex lens 2 molded by the method of the present embodiment, the third resin layer 2-3 that is post-laminated is laminated between the first and second resin layers 2-1 and 2-2 that are pre-laminated. In the molded structure (see FIG. 12), the cooling rate of the third resin layer 2-3 post-applied is substantially the same at the interface with the first and second resin layers 2-1 and 2-2. (There is no difference), so no heat sink occurs in the third resin layer 2-3. Therefore, according to the method of the present embodiment, the projection convex lens 2 having excellent quality free from heat sink is obtained.

  As shown in FIG. 14, the convex lens 2 is a convex lens body formed by the molding surface 32 (the concave spherical surface 32 a) of the movable mold 30 and the molding surface 22 (the concave plane 22 a) of the fixed mold 20. 2a, and a circle with a predetermined width formed by an annular concave flat surface 32b near the outer periphery of the molding surface 32 of the movable die 30 and a dividing surface 21 of the fixed die 20 at the periphery of the convex lens body 2a. An annular flange portion 2b is integrally formed.

  Since the molding surface 22 (the concave flat surface 22a) of the fixed mold 20 is slightly recessed with respect to the dividing surface 21, the convex lens body 2a and the flange are formed on the back side of the convex lens 2 as shown in FIGS. A stepped portion 2d is formed between the portion 2b. Further, a convex portion 2e corresponding to the side gate forming groove 25a is formed flush with the step portion 2d at the base position of the resin molded body 3.

  However, by using only the region close to the central axis L of the convex lens body 2a that does not cover the stepped portion 2d as the light distribution forming region, the light distribution function as the convex lens 2 is not impaired by the stepped portion 2d or the convex portion 2e. . In addition, the code | symbol D1 in FIG. 14 shows the effective light distribution formation area in the convex lens 2. FIG.

  Further, as shown in FIGS. 12 and 14, the convex lens 2 is composed of a laminated body of first, second and third resin layers 2-1, 2-2 and 2-3, but the convex lens body 2a. Is composed of three layers of first, second, and third resin layers 2-1, 2-2, and 2-3, and the flange portion 2b is composed of a single layer of the third resin layer 2-3. Yes.

  The flange portion 2b of the convex lens 2 is formed of a third resin layer 2-3 single layer, and cracks and peeling at the lamination interface occur compared to a structure in which the flange portion 2b is formed of a plurality of layers. The injection pressure at the time of secondary molding can be reduced because the risk is small and the flow of the resin for molding the flange portion 2b becomes smooth.

  Next, according to the molding method and the molding apparatus according to the present embodiment, there are the following effects.

  In order to laminate and form the convex lens 2 having three layers as shown in FIGS. 12 and 14 according to the prior patent document 1, the mold closing → injection → holding pressure (molding) → mold opening → moving side mold rotation 5 The process is repeated three times, and a total of 15 processes are required. In this embodiment, although two processes of “core insertion” and “core extraction” are added, mold closing → injection → pressure holding (molding) → The series of steps of mold opening need only be repeated twice (primary molding and secondary molding). Specifically, all 10 steps from core insertion → mold closing → injection → pressure holding (primary molding) → mold opening → core removal → mold closing → injection → pressure holding (secondary molding) → mold opening are all necessary. In this example, it is clear that the molding cycle is shorter than that of the prior art document 1.

  Moreover, in prior patent document 1, since the mold closing and mold opening of the plurality of cavities are all performed at the same timing, the mold opening timing (pressure holding time) is set based on the required pressure holding time that is the longest of the plurality of cavities. In contrast to this, in this embodiment, different holding pressure times can be set for primary molding and secondary molding. Therefore, by selecting the optimal holding time for primary molding and secondary molding, the molding cycle can be increased. It becomes even shorter.

  In particular, in the prior art document 1, since one molding surface of the cavity is a resin layer that is preliminarily applied, it takes some time until the resin layer that has been post-adjusted cools down. Cavities for primary molding (C1, C2) are composed of molds 20, 30 and a core 40 having excellent thermal conductivity, so that the resin layers 2-1 and 2-2 filled in the cavities C1, C2 The time required for cooling is shorter than that of the prior art document 1, and the required pressure holding time in the primary molding is shortened accordingly, and the molding cycle is further shortened.

  In addition, the molding apparatus 10 according to the present embodiment includes a pair of molds 20 and 30 that can be closed and opened, a split surface 21 and 31 of the molds 20 and 30, and a handle 42 and a flange portion 41b that are a part thereof. Is configured by a removable core 40 that is sandwiched and engaged with the opening side of the molding surface 32 to divide the cavity C in the mold closing direction of the molds 20 and 30. In addition to being compact.

  Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 15 is an enlarged vertical cross-sectional view of a main part of a mold of a projection convex lens molding apparatus according to a second embodiment of the present invention (cross-sectional view corresponding to FIG. 8), and FIG. FIG. 17 is a longitudinal sectional view of a projection convex lens molded by the molding apparatus (FIG. 14). FIG.

  In the molding apparatus 10 of the first embodiment described above, as shown in FIG. 8, the thickness of the flange portion 41 b of the core body 41 is such that the molding surface 32 provided on the split surface 31 of the movable side mold 30. The outer diameter dimension of the molding surface 22 formed by the concave flat surface 22a provided on the dividing surface 21 of the fixed-side mold 20 and corresponding to the depth of the concave flat surface 32b, and the longitudinal section of the core body 41 When the outer diameter dimensions of the center arc region 41 a having a circular arc shape are matched to each other and the molds 20 and 30 are clamped, almost the entire flange portion 41 b of the core body 41 is formed on the movable side mold 30. A part of the molding surface 32 (concave flat surface 32 b) and the split surface 21 of the stationary mold 20 are configured to be sandwiched.

  On the other hand, in the molding apparatus 10A of the second embodiment, as shown in FIGS. 15 and 16, a molding surface 22A composed of a concave concave plane 22a ′ having a circular front view provided on the split surface 21A of the stationary mold 20A. When the molds 20A and 30 are clamped by setting the outer diameter dimension of the core body 41 to be larger than the outer diameter dimension of the central region 41a having a circular arc cross section of the core body 41, the peripheral edge of the flange body 41b of the core body 41 Only a region 41b2 having a predetermined width close to the portion is sandwiched between a part of the molding surface 32 (concave surface 32b) provided on the dividing surface 31 of the movable mold 30 and the dividing surface 21A of the fixed mold 20A. The difference is that it is configured.

  Other configurations are the same as the structure of the molding apparatus 10 of the first embodiment described above, and the description thereof is omitted by attaching the same reference numerals.

  As shown in FIG. 17, the convex lens 2A molded by the molding apparatus 10A of the second embodiment is a laminate of first, second, and third resin layers 2-1, 2-2, and 2-3. The convex lens body 2a is composed of three layers of first, second and third resin layers 2-1, 2-2 and 2-3, whereas the flange portion 2b The base side is composed of two layers, first and third resin layers 2-1, 2-3, and the tip side is composed of a third resin layer 2-3 single layer. In addition, the code | symbol D2 in FIG. 17 shows the effective light distribution formation area in 2 A of convex lenses, and is larger than the effective light distribution formation area D1 which the convex lens 2 shape | molded by the method and apparatus 10 of the said 1st Example.

  The flange portion 2b is composed of two layers of the first and third resin layers on the base side, and a single third layer of the third resin layer 2-3 on the tip side, and the flange portion 2b is formed of three layers. Compared to the structure (see FIG. 21), there is less risk of cracking and peeling at the lamination interface, and the flow of the resin that forms the flange portion becomes smoother, so injection during primary molding and secondary molding Each pressure can be reduced.

  Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 18 is an enlarged vertical sectional view of the main part of the mold of the projection convex lens molding apparatus according to the third embodiment of the present invention (cross-sectional view corresponding to FIG. 8), and FIG. FIG. 20 is a longitudinal sectional view of the main part of the mold at the position of the runner forming groove formed in FIG. 20 (cross-sectional view corresponding to FIG. 5B). FIG. 20 shows the side gate forming groove provided on the dividing surface of the movable mold. FIG. 21 is a longitudinal sectional view of a projection convex lens molded by the molding apparatus (cross-sectional view corresponding to FIG. 14).

  In the molding apparatuses 10 and 10A of the first and second embodiments described above, as shown in FIGS. 8 and 15, the thickness of the flange portion 41 b of the core body 41 in the core 40 is divided into the movable mold 30. Although it corresponds to the depth of the concave flat surface 32b provided on the surface 31, in the molding apparatus 10B of the third embodiment, first, as shown in FIGS. 18 and 19, the core body 41A in the core 40A. The flange portion 41b 'is formed larger than the flange portion 41b of the core body 41 of the first and second embodiments described above, and the thickness of the flange portion 41b' is thinner than the flange portion 41b. It is formed to have a thickness about half the depth of the concave flat surface 32 b of the molding surface 32 provided on the dividing surface 31 of the movable mold 30.

  Second, an annular concave plane 32b ′ surrounding the concave spherical surface 32a formed on the split surface 31A of the movable mold 30A is substantially the same as the concave plane 22a ′ constituting the molding surface 22A of the fixed mold 20A. The first concave flat surface 32b1 radially inward and formed at the same outer diameter and the flange portion 41b 'of the core body 41A can be engaged with each other at a depth and outer diameter that are closer to the outer side in the radial direction. It is composed of a second concave plane 32b2. That is, the molding surface 32A of the movable mold 30A has a first concave plane 32b1 concentrically surrounding the concave spherical surface 32a at a position corresponding to the step position of the peripheral edge of the concave plane 22a ′ of the fixed mold 20A. A step 32b3 that separates the second concave flat surface 32b2 on the outside is formed.

  Then, when the molds 20A and 30A are clamped, only a region 41b ″ having a predetermined width near the peripheral edge in the flange portion 41b ′ of the core body 41 is a part of the molding surface 32A of the movable mold 30A (second The concave flat surface 32b2) and the split surface 21A of the stationary mold 20A are configured to be sandwiched.

  Further, as shown in enlarged views in FIGS. 18 and 20, the runner formation groove 34a communicates with the division cavity C2 on the division surface 31A of the movable mold 30A in cooperation with the side gate formation groove 35a. A side gate forming groove 35b extending in a letter shape is formed. That is, in the primary molding performed in the form in which the cavity C is divided by the core 40A, the primary molding resin guided to the runner 34 through the valve gate 27 is formed between the side gate forming groove 35a and the side gate forming. The light is injected into the split cavity C2 through the side gate 35 ′ constituted by the groove 35b.

  Other configurations are the same as the structures of the molding apparatuses 10 and 10A of the first and second embodiments described above, and the description thereof is omitted by giving the same reference numerals.

  As shown in FIG. 21, the convex lens 2B molded by the molding apparatus 10B of the third embodiment is a laminate of first, second, and third resin layers 2-1, 2-2, and 2-3. The convex lens body 2a is composed of three layers of first, second and third resin layers 2-1, 2-2 and 2-3, whereas the flange portion 2b The base side is composed of three layers of first, second and third resin layers 2-1, 2-2 and 2-3, and the tip side is composed of a third resin layer 2-3 single layer. Yes.

  21 indicates an effective light distribution formation region in the convex lens 2B, and is larger than the effective light distribution formation region D1 of the convex lens 2 formed by the method and apparatus 10 of the first embodiment.

  22, 23, and 24 show another embodiment of the present invention, and FIGS. 22 and 23 show a movable side mold and a fixed side mold, which are main parts of a projection convex lens molding apparatus according to another embodiment. FIG. 23 is a front view of a core unit used in the apparatus.

  In the molding apparatuses 10, 10A, 10B of the first to third embodiments described above, one convex lens 2, 2, 2A, 2B is molded by a pair of molds. The example molding apparatus 10C is configured to simultaneously mold a plurality of (four in the embodiment) convex lenses 2 by a pair of molds 20C and 30C.

  That is, as shown in FIGS. 23 and 22, the four molding surfaces 22 and 32 are opposed to the dividing surface 21C of the fixed die 20C and the dividing surface 31C of the movable die 30C at equal intervals in the circumferential direction, respectively. Runner forming grooves 24a extending radially outward from the respective molding surfaces 22 are provided on the dividing surface 21C, and runners extending radially outward from the respective molding surfaces 32 are provided on the dividing surface 31C. A formation groove 34a and a runner formation groove 36a are provided.

  Specifically, in the vicinity of the center of the dividing surface 31C of the movable mold 30C, as shown in FIG. 22, in cooperation with the dividing surface 21C of the fixed mold 20C, a cross-shaped handle 42 in the core unit 40C. Four runner formation grooves 36a sandwiching (see FIG. 24) are formed to be orthogonal to each other, and each runner formation groove 36a communicates with the molding surface 32 via a side gate formation groove 37a. The runner formation groove 34a is formed in a direction of 120 degrees with respect to the runner formation groove 36a, and each runner formation groove 34a communicates with the molding surface 32 via the side gate formation groove 35a.

  Further, as shown in FIG. 23, secondary molding is performed on each of the four runners 36 formed between the divided surfaces 21 </ b> C and 31 </ b> C of the molds 20 </ b> C and 30 </ b> C, as shown in FIG. 23. A common valve gate 27 for supplying the resin for resin is opened, and the runners 24 formed between the divided surfaces 21C and 31C of the molds 20C and 30C are also located at 120 degrees in the circumferential direction of the molding surfaces 22. Valve gates 27 for supplying primary molding resins to 34 are opened. Further, each molding surface 22 formed on the split surface 21C and the runner formation groove 24a extending outward in the radial direction communicate with each other via the side gate formation groove 25a.

  The molten resin in the hot runner 26 provided on the stationary mold 20C is passed through the valve gate 27 to the runners 24, 34, 36 formed on the split surfaces 21C, 31C of the molds 20C, 30C that are closed. Are supplied respectively.

  Further, the core unit 40C for dividing the cavities C defined by the molding surfaces 32 and 22 in the mold closing direction is, as shown in FIG. 24, the core 40 used in the first embodiment (see FIG. 2). ) Are integrated so that each handle 42 has a cross shape, and each core body 41 in the core unit 40C has an opening side of each molding surface 32 formed on the split surface 31C of the mold 30C. And the cross-shaped handle 42 of the core unit 40C can be engaged with a runner-forming groove 36a (see FIG. 22) formed in the cross-shape formed on the split surface 31C.

  In addition, in a predetermined position on the outer peripheral edge of the annular flange portion 41b of each core body 41, as shown in FIG. 24, in cooperation with the side gate forming groove 35a provided on the dividing surface 31C of the mold 30C, An L-shaped side gate forming groove 41b1 (see FIGS. 2 and 8) is formed to communicate the runner forming groove 34a with the split cavity C2. In other words, the primary molding resin guided to the runner 34 through the valve gate 27 in the primary molding performed in the form in which the cavity C is divided by the core body 41 is constituted by the side gate forming grooves 35a and 41b1 communicating with each other. Injected into the split cavity C2 through the side gate 35 (see FIGS. 2 and 8).

  Then, by moving the core unit 40C toward and away from the split surface 31C of the movable mold 30C that has been opened, the core body 41 and the handle 42 are moved to the molding surfaces 32 and the runner forming grooves 36a. Can be assembled and removed at the same time.

  Others are the same as in the first embodiment described above, and a duplicate description thereof is omitted.

  In the various embodiments described above, for example, as shown in the first embodiment, the runner 24 is constituted by a runner forming groove 24a formed in the dividing surface 21 of the stationary mold 20, and the runners 34, 36 are movable. The runner forming grooves 34 a and 36 a are formed on the dividing surface 31 of the side mold 30. The runners 24, 34 and 36 are formed as grooves on either side of the dividing surfaces 21 and 31 of the molds 20 and 30. It may be formed, or may be formed as a groove extending over both the dividing surfaces 21 and 31.

  Further, in the various embodiments described above, the front side is a continuous convex spherical lens, and the back side is formed into a flat surface, and the front side is a circular convex lens. The method and apparatus for molding the convex lenses 2, 2 </ b> A, 2 </ b> B (see FIGS. 14, 17, 21) formed in an annular shape have been described, but the molding surfaces 22, 32 formed on the split surfaces 21, 31 of the molds 20, 30. By appropriately changing the shape of the runners 24, 34, 36, the shape of the core 40, etc., the front side is formed with a spherical surface having a large curvature, and the back side is the front side as shown in FIGS. It is also possible to mold a convex lens 2C which is a convex lens having a substantially rectangular shape in front view and formed with a spherical surface having a smaller curvature than the left and right side edge portions of which a flange portion 2b having a predetermined width is formed.

C cavity
C1, C2 split cavity (cavity for primary molding)
New cavity corresponding to C3 core volume (cavity for secondary molding)
2, 2A, 2B, 2C Projection convex lens 2a which is an optical member Convex lens body 2b Flange
2-1 and 2-2 First transparent resin layer and second transparent resin layer which are primary molded bodies
2-3 Third transparent resin layers 10, 10A, 10B, 10C constituting secondary molded bodies together with the first and second transparent resin layers Convex lens forming devices 20, 20A, 20C Fixed side molds 21, 21A, 21C Fixed-side mold dividing surfaces 22, 22A Fixed-side mold molding surfaces 22a, 22a 'Recessed flat surfaces 24, 34 Runners 25, 35, 35', 37 which are resin passages for primary molding Side gates 26 Hot runners 27 Valves Gates 30, 30A, 30C Movable molds 31, 31A, 31C Movable mold split surfaces 32, 32A Movable mold molding surfaces 32a Molded concave spherical surfaces 32b, 32b, 32b 'Molding surface peripheral portions Recessed flat surfaces 35a, 41b1, 35b Side gate forming groove 36 Runner 36a, which is a resin passage for secondary molding, Runner forming grooves 40, 40A Core 40C Knit 41 core body 41a tang central region 41b of the body, 41b 'core body of the flange portion 42 handle 50 moldings core ejector pins 60 type closed-type opening mechanism 70 injection machine which also serves as a knockout pin

Claims (7)

In a molding method of an optical member in which a cavity defined by a pair of molds to be closed is filled with a resin and molded,
A primary molding step of dividing the cavity in the mold closing direction of the mold by a core partly sandwiched between the divided surfaces of the mold, and injecting and molding a resin into each divided cavity;
The mold is opened so that the first resin layer, which is a primary molded body, is attached to one of the molds, and the second resin layer, which is the primary molded body, and the core are attached to the other, and the core is taken out. Child removal process;
A secondary molding step of closing the mold again and injecting and molding the resin into a new cavity formed between the first and second resin layers and corresponding to the volume of the core. An optical member molding method characterized by the above.   2. The groove according to claim 1, wherein a groove provided along a dividing surface of the mold and engaged with a part of the core is used as a runner for guiding a secondary molding resin to the new cavity. The molding method of the optical member of description. The core is formed with a handle that engages with the groove, and at least a part of the peripheral edge of the core is formed with a flange portion that is sandwiched between the split surfaces of the mold,
The method for molding an optical member according to claim 2, wherein primary molding is performed in a form in which a split surface of the mold sandwiches at least a part of the flange portion and the handle.   The method for molding an optical member according to claim 3, wherein primary molding is performed in such a manner that the dividing surface of the mold sandwiches at least the peripheral portion of the flange portion. An optical system that includes a fixed mold and a movable mold that can move toward and away from the fixed mold, and injects resin into a cavity defined by the pair of molds that are closed. In a member forming apparatus,
A removable core that is partly sandwiched between the mold split surfaces and splits the cavity in the mold closing direction of the mold;
A primary molding cavity is constituted by a pair of split cavities defined by the mold and the core,
After the primary molding, the mold is opened so that the first resin layer, which is the primary molded body, is attached to one of the molds, and the second resin layer, which is the primary molded body, and the core are attached to the other. A secondary molding cavity is formed by a new cavity corresponding to the volume of the core formed between the first and second resin layers by closing the mold again after taking out the core. An optical member molding apparatus.   A runner for guiding a secondary molding resin to the new cavity is provided on the split surface of the mold, and the runner functions as a groove with which a part of the core is engaged. Item 6. The optical member molding apparatus according to Item 5. An optical member molded by the method according to claim 1,
The optical member is composed of a secondary molded body in which a third resin layer that is post-fired is laminated between first and second resin layers that are primary molded bodies that are pre-fired. .

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