JP2013159015A - Mold and method for manufacturing optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold capable of preventing damage on releasing and generation of internal stress in an optical element.SOLUTION: In opening the mold by separating the first mold, or a movable mold 41, from the second mold, or a fixed mold 42, a molding MP, or a lens 10, can be separated preliminarily from the first core portion 64a by shifting the first member 51 from a first to a second position by means of an ejection member 53. The preliminary release ensures release of the lens 10 from the first mold, or the movable mold 41, and enables to control distortion, damage, occurrence of internal stress, etc., of the lens 10, or a lens 10 optical element. Since the lens 10 can be released at an early timing from the first core portion 64a of the first mold, or the movable mold 41, occurrence of warpage in the lens 10 due to a contraction difference between at the base and at the tip of the lens 10 can also thus be prevented.

Description

  The present invention relates to a molding die for molding an optical element, and a method for manufacturing an optical element using the molding die.

  As a molding die for forming an optical element by injection molding, a fixed-side mold member and a movable-side mold member are provided, and a lens is placed on the required molding surface by the operation of the movable-side mold member for opening the mold. There is a configuration in which the lens is peeled from the fixed mold member while being held, and then the lens is released from the movable mold member (see Patent Document 1). Here, the movable mold member includes a first core that constitutes a part of the cavity for molding other than the optical surface, and a second core having a molding surface for forming the optical surface. The second core moves relative to the second core with a clearance at a position near the cavity so that the second core functions as a protruding guide member that protrudes the lens from the first core over the entire molding surface. .

  In the molding die, when the molded product including the lens is ejected from the molding die by the ejecting machine after the second core is projected, the lens sticks to the second core, and the gate extends from the lens. May be bent. When deformation occurs when the core and the lens are separated from each other, scratches are generated due to the contact at the time of separation, or internal stress is generated in the lens, and a desired optical surface cannot be obtained.

JP-A-10-128803

  An object of the present invention is to provide a molding die capable of preventing scratches during mold release or internal stress from being generated in an optical element.

  It is another object of the present invention to provide a method for manufacturing an optical element that can prevent scratches during mold release or internal stress in the optical element.

  In order to solve the above problems, a molding die according to the present invention includes a first mold for molding the first optical surface of the optical element, and a second mold for molding the second optical surface of the optical element. The first mold has a core part that molds the center side of the optical element, and a holding part that holds the core part and molds the peripheral side of the optical element, and the holding part is on the tip side. A first member arranged and movable along the axial direction of the core part; a second member fixed directly or indirectly to the core part to support the first member; and the first member as a root And a projecting member that moves from the first position on the side to the second position on the tip side.

  In the molding die, the holding portion includes a first member disposed on the distal end side, a second member that supports the first member, and the first member from the first position on the root side to the second position on the distal end side. And a projecting member that moves the first member to the second position by the projecting member when the mold is opened to separate the first mold and the second mold. It can be released from the core portion in advance. As a result, the molded product can be reliably released from the first mold, and the molded product can be easily taken out between the first mold and the second mold. It is possible to suppress deformation, scratches, generation of internal stress, and the like of the optical element as a product. In addition, since the molded product can be released from the core portion of the first mold at an early timing, a phenomenon that the cooling of the molded product, that is, the optical element, differs greatly between the root side and the tip side can be prevented, and the fundamental of the optical element can be prevented. It is possible to prevent the optical element from being warped and deformed due to the difference in contraction between the side and the tip side.

  In a specific aspect or aspect of the present invention, in the molding die, the first member is disposed at the first position on the root side during molding, and the first die and the second die are separated from each other. It moves from the first position to the second position on the tip side when the mold is opened. In this case, since the first member is moved forward to the tip in synchronization with the mold opening, the process after the mold opening is shortened and the manufacturing cycle is shortened as compared with the case where the molded product is extruded after the mold opening is completed. it can.

  In another aspect of the present invention, the protruding member is an elastic member that expands and contracts between the first member and the second member. In this case, the first member can be moved from the first position to the second position by utilizing the separation between the first mold and the second mold when the mold is opened. At this time, the speed of the mold release operation of the molded product from the core portion can be controlled by adjusting the speed of separation between the first mold and the second mold.

  In still another aspect of the present invention, the first member urges the entire peripheral side of the optical element to be advanced from the first position to the second position. In still another aspect of the present invention, the first member partially supports the peripheral side of the optical element and biases it to advance from the first position to the second position.

  In still another aspect of the present invention, the first member is held in the second member and slides along the axial direction of the core portion. By adjusting the shapes of the first member and the second member, the stroke of the first member sliding in the second member can be adjusted.

  In still another aspect of the present invention, the first member is supported on the second member by the sliding portion. The sliding portion is, for example, a bearing, and can be an oil-free bush.

  In still another aspect of the present invention, the second member of the holding portion includes a locking member that defines an axial displacement amount of the first member, and a support member that supports the locking member. In this case, the locking member and the support member can be individually manufactured, and partial parts can be exchanged, so that maintenance efficiency can be improved.

  An optical element manufacturing method according to the present invention includes a molding die having a first mold for molding a first optical surface of an optical element and a second mold for molding a second optical surface of the optical element. The first mold has a core part that molds the center side of the optical element, and a holding part that holds the core part and molds the peripheral side of the optical element. The holding portion is disposed on the distal end side and is movable along the axial direction of the core portion, and a second member that is directly or indirectly fixed to the core portion and supports the first member. The optical element is released from the core portion earlier than the holding portion by moving the first member of the holding portion from the first position on the base side to the second position on the distal end side.

  In the manufacturing method of the optical element, the optical element is released from the core portion earlier than the holding portion by moving the first member of the holding portion from the first position on the base side to the second position on the tip side. Before removing the molded product from between the first mold and the second mold, the molded product can be reliably released from the first mold. Thereby, the deformation | transformation of the optical element which is a molded article, a damage | wound, generation | occurrence | production of internal stress, etc. can be suppressed. Further, since the molded product is released from the core portion of the first mold at an early timing, it is possible to prevent a phenomenon in which the cooling of the molded product, that is, the optical element, is greatly different between the root side and the tip side. It is possible to prevent the warp deformation of the optical element due to the shrinkage difference on the side. Furthermore, since the optical element is released from the core part earlier than the holding part, it is not necessary to protrude the molded product after the mold opening is completed, the process after the mold opening is shortened, and the manufacturing cycle can be shortened.

  In a specific aspect or aspect of the present invention, in the method for manufacturing an optical element, the first member is moved from the first position on the root side when the mold is opened to separate the first mold and the second mold. Move to the second position on the tip side.

  In another aspect of the present invention, the first member is moved from the first position to the second position by the protruding member.

  In still another aspect of the present invention, the protruding member is an elastic member that is stretched by being sandwiched between the first member and the second member.

  In still another aspect of the present invention, the optical element released from the core portion is taken out between the first mold and the second mold by chucking a runner or sprue extending from the optical element. . Further, the optical element released from the core portion can be taken out between the first mold and the second mold by directly adsorbing the optical element.

It is a conceptual diagram of the injection molding apparatus incorporating the molding die of 1st Embodiment. FIG. 2 is a partially enlarged side sectional view of the molding die in FIG. 1. (A) is a figure explaining the type | mold space formed with the metal mold | die for shaping | molding, (B) is a figure explaining the molded article shape | molded with the metal mold | die for shaping | molding. (A) And (B) is side sectional drawing explaining operation | movement of a holding | maintenance part. It is a flowchart explaining operation | movement of the injection molding apparatus of FIG. It is a partial expanded sectional view explaining the metal mold | die of a modification. (A) And (B) is the partial expanded sectional view and end elevation explaining the metal mold | die of another modification. (A) And (B) is the partial expanded sectional view and end elevation explaining the metal mold | die of another modification. (A) And (B) is a figure explaining the modification of an injection molding apparatus.

  Hereinafter, a molding die according to an embodiment of the present invention and an optical element manufacturing method using the molding die will be described.

  As shown in FIG. 1, an injection molding apparatus 100 includes a molding die 40 for transferring a shape corresponding to a molded product. The molding die 40 is a horizontal type in the illustrated example, and includes a movable die 41 and a fixed die 42 that both extend in the horizontal direction and are arranged to face each other.

  Of the molding dies 40, the movable die 41, which is the first die, is driven by the opening / closing drive device 81 and can reciprocate in the AB direction. A mold space for molding an optical element, which will be described later, by moving the movable mold 41 toward the fixed mold 42, aligning both molds 41, 42 with the parting surfaces PS1, PS2, and clamping the mold. Etc. are formed. In each of the molds 41 and 42, the front side with the parting surfaces PS1 and PS2 is the tip side, and the far side away from the parting surfaces PS1 and PS2 is the base side.

  As shown in FIGS. 1 and 2, the movable mold 41 includes a first core part 64a as a central part that forms a mold space from one side, and a holding part as a peripheral part provided around the first core part 64a. 64s, an outer peripheral part 64b provided around the holding part 64s, a first core part 64a, a holding part 64s, a receiving plate 64c for supporting the outer peripheral part 64b from behind, and a movable part for protruding a part of the molded product A pin 64p, a movable rod 66 that pushes the movable pin 64p from behind, and an advance / retreat mechanism 68 that moves the movable rod 66 back and forth in the AB direction along the axis AX.

  The first core portion 64a is incorporated and fixed in a through hole 64g formed in the holding portion 64s. The holding portion 64s is incorporated and fixed in a through hole 64h formed in the outer peripheral portion 64b.

  The holding portion 64s is disposed on the distal end side and accommodates the first member 51 that is movable along the axis AX direction of the first core portion 64a, and stores the first member 51 and is fixed to the first core portion 64a. The second member 52 and the protruding member 53 that is housed in the second member 52 and biases the first member 51 to move to the distal end side. The first member 51 and the second member 52 are components that can be individually replaced, and are fixed to each other by a bolt (not shown) or fixed to the outer peripheral portion 64b or the like. Furthermore, the second member 52 includes a locking member 52a that holds the first member 51 from the periphery as a portion disposed on the distal end side, and a support member 52b that supports the locking member 52a as a portion disposed on the root side. Have Here, the first member 51 is an annular member housed in a recess R1 provided in the second member 52, and the second member 52 is a cylindrical member as a whole. The protruding member 53 is a spring-like elastic member that is accommodated in the recess R <b> 2 provided in the second member 52 and expands and contracts.

  The fixed mold 42 as the second mold includes a second core part 74a as a central part that forms a mold space from the other side, and a second outer peripheral part 74b as a peripheral part provided around the second core part 74a. And a receiving plate 74c that supports the second core portion 74a and the second outer peripheral portion 74b from behind. Here, the 2nd core part 74a is a shaft-shaped member, and is incorporated and fixed in the through-hole 74g formed in the 2nd outer peripheral part 74b.

  As shown in an enlarged view in FIG. 3A, a mold space CV formed by closing the movable mold 41 and the fixed mold 42 is sandwiched between the first and second transfer surfaces S1 and S2. Main body space CV1, and flange space CV2 surrounded by the third, fourth, and fifth transfer surfaces S3, S4, and S5. The mold space CV is a part for forming the lens 10 as an optical element in the molded product MP shown in FIG. The flow path space FC extending from the mold space CV has a runner portion RS as a space for forming the runner portion RP in the molded product MP shown in FIG. 3B. The runner portion RS is a gate portion GS. Is communicated with the mold space CV. The space of the gate portion GS forms a gate portion GP that connects the lens 10 and the runner portion RP in the molded product MP. The end surface 64e of the movable mold 41 is formed with a recess to be the runner part RS of the molded product MP, and the end surface 74e of the fixed mold 42 is also the runner part RS of the molded product MP. A power recess is formed.

  Returning to FIG. 2, in the movable mold 41, the first transfer surface S1 is provided at the tip of the first core portion 64a, and the third and fifth transfer surfaces S3 and S5 are the first member 51 of the holding portion 64s. It is provided at the tip. In the fixed mold 42, the second and fourth transfer surfaces S2 and S4 are provided at the tip of the second core portion 74a. Here, the pair of opposing first and second transfer surfaces S1 and S2 form the first and second optical surfaces 11a and 11b of the central optical function unit 11 in the lens 10 shown in FIG. 3B. It is a part for. In this case, one first transfer surface S1 is deeper and larger in curvature than the other second transfer surface S2, and a fine uneven pattern for transferring the fine structure or fine shape FS of the first optical surface 11a. An FP is provided. On the other hand, the third and fourth transfer surfaces S3 and S4 are portions for forming the first and second flange surfaces 12a and 12b of the peripheral flange portion 12, and the fifth transfer surface S5 is the portion of the flange portion 12. It is a part for forming the side surface 12c. The illustrated lens 10 is an objective lens for an optical pickup device, and the first optical surface 11a is disposed on the light source side, and the second optical surface 11b is disposed on the recording medium side such as an optical disk.

  Hereinafter, the structure and operation of the holding portion 64s will be described. Of the holding portion 64s, the first member 51 is formed of the same or different kind of metal material, ceramic material, or the like as the first core portion 64a, and has a base portion 51a and a tip portion 51b. The base portion 51a has an inner side surface 51d and an outer side surface 51e, the inner side surface 51d is arranged to face the side surface 64k of the first core portion 64a, and the outer side surface 51e is formed of the locking member 52a of the second member 52. It arrange | positions facing the 2nd inner surface 52f. Here, the inner side surface 51d of the first member 51 and the side surface 64k of the first core portion 64a can be brought into close contact with each other to allow sliding, but can also be separated to such an extent that resin inflow can be prevented. it can. The tip 51b has the above-described third and fifth transfer surfaces S3 and S5 on the inside, and has a step 51f whose diameter is reduced at the tip on the outside. The first member 51 supports the flange portion 12 of the lens 10 by the tip portion 51b, and the lens 10 can be moved in the axis AX direction, that is, the optical axis direction by the movement of the first member 51 in the axis AX direction. it can.

  The locking member 52a of the second member 52 in the holding portion 64s is an annular member, and is formed of the same or different kind of metal material as the first member 51. The locking member 52a has a stepped portion 52h on the inner side and a cylindrical side surface 52g on the outer side. The thickness width in the axis AX direction of the protruding portion 52i on the distal end side in the stepped portion 52h is smaller than the depth width of the stepped portion 51f provided on the distal end side of the first member 51, and the inner side surface 52v of the protruding portion 52i The outer surface 51v of the tip 51b of the first member 51 is separated to the extent that resin can be prevented from flowing in, and allows the first member 51 to move in the axis AX direction. A bearing 55, which is a bearing having, for example, a sliding ball or the like, is formed on the inner surface of the step portion 52h on the base side. With this bearing 55, the first member 51 can be moved smoothly and with a small inclination along the axis AX in the recess R1 of the second member 52. The cylindrical side surface 52g of the locking member 52a is in close contact with the through hole 64h of the outer peripheral portion 64b and is precisely positioned and fixed in the through hole 64h.

  The support member 52b of the second member 52 is a cylindrical member, and is formed of the same or different kind of metal material or the like as the locking member 52a. The support member 52b has a stepped portion 52m at the inner tip and a cylindrical side surface 52n on the outer side. A protruding member 53, which is a spring coil, is disposed in the recess R2 formed between the stepped portion 52m and the side surface 64k of the first core portion 64a. The protruding member 53 is elastically extendable in the direction of the axis AX, and is housed in a compressed state in the recess R2 while being sandwiched between the bottom surfaces 51s and 52s. That is, the protruding member 53 urges the first member 51 housed in the second member 52 and pushes it upward in FIG. 2, so that the front end surface 51 t of the first member 51 is changed to the front end surface 52 t of the second member 52. Can protrude more. The cylindrical side surface 52n on the outside of the support member 52b is in close contact with the through hole 64h of the outer peripheral portion 64b and is precisely positioned and fixed in the through hole 64h.

  FIG. 4A shows a state in which the movable first member 51 is pushed by applying an external force, and corresponds to a mold clamping state in which the movable mold 41 and the fixed mold 42 are brought into close contact with each other. In this case, the first member 51 is in the pushed-in first position. On the other hand, FIG. 4B shows a state in which the movable first member 51 is opened without applying an external force, and corresponds to a mold open state in which the movable mold 41 and the fixed mold 42 are separated. Here, the thickness width t1 in the axis AX direction of the protrusion 52i provided on the second member 52 is smaller than the depth width t2 of the step 51f provided on the first member 51, and the tip surface 51t of the first member 51 is , It protrudes from the surrounding tip surface 52t by the differential stroke amount Δt. That is, the first member 51 moves to the second position protruding from the pushed first position. Accordingly, the first optical surface 11a of the central optical function unit 11 in the lens 10 is separated from the first transfer surface S1 of the first core unit 64a. That is, the release of the optical function unit 11 of the lens 10 is performed. By adjusting the distance at which the movable mold 41 is separated from the fixed mold 42, the amount by which the tip surface 51t of the first member 51 protrudes from the tip surface 52t of the second member 52 can be adjusted. By adjusting the speed at which the mold 41 is moved, the protruding speed of the tip surface 52t of the second member 52 can be adjusted. That is, although depending on the spring strength of the protruding member 53, the distance and speed at which the lens 10 is separated from the first transfer surface S1 of the first core portion 64a can also be adjusted.

  FIG. 5 is a flowchart conceptually illustrating a method for manufacturing the lens 10 using the injection molding apparatus 100 or the molding die 40 shown in FIG.

  First, the opening / closing drive device 81 is operated, and the mold closing is started by relatively moving the movable mold 41 toward the fixed mold 42 (step S11). Note that the surfaces of both molds 41 and 42 are heated to a temperature suitable for molding.

  By continuing the closing operation of the opening / closing drive device 81, as shown in FIG. 4 (A), the movable mold 41 and the fixed mold 42 are moved to the position where they come into contact with each other, and the mold closing is completed. By further continuing the closing operation of the driving device 81, mold clamping is performed to clamp the movable mold 41 and the fixed mold 42 with necessary pressure (step S12).

  Next, a vacuum device (not shown) is operated to depressurize the mold space CV between the clamped movable mold 41 and fixed mold 42 (step S13). As a result, the mold space CV is appropriately decompressed, and the molten resin is reliably filled into the first transfer surface S1 having a relatively large curvature.

  Next, an injection device (not shown) is operated to inject the molten resin into the mold space CV with a necessary pressure (step S14). The injection device maintains the resin pressure in the mold space CV.

  After the molten resin is introduced into the mold space CV, the molten resin in the mold space CV is gradually cooled by heat dissipation, so that the molten resin is solidified with the cooling and waits for completion of molding (step S15).

  Next, the opening / closing drive device 81 is operated to perform mold opening that relatively moves the movable mold 41 backward (step S16). As the movable mold 41 moves backward, the movable mold 41 and the fixed mold 42 are separated from each other. At this time, the movable mold 41 is gradually retracted. First, the lens 10 is pushed together with the first member 51 by being pushed by the protruding member 53. That is, the lens 10 of the molded product MP is ejected (step S17). Thereby, the first optical surface 11a of the lens 10 is separated from the first transfer surface S1 of the first core portion 64a. That is, the lens 10 as an optical element is released from the core portion 64a earlier than the holding portion 64s. After that, when the retreat of the movable mold 41 is continued, the first member 51 protrudes to the maximum extent (see FIG. 4B). In synchronization with this, the advance / retreat mechanism 68 is operated, and the molded product MP remaining on the movable mold 41 is pushed out to the fixed mold 42 side by the movable rod 66. Further, when the movable mold 41 is continuously retracted, the second optical surface 11b and the second flange surface 12b of the lens 10 are separated from the second and fourth transfer surfaces S2 and S4 of the fixed mold 42, and the fixed mold 42 is moved. Release is completed on the side. Thereby, although the molded product MP adheres loosely to the movable mold 41, the substantial release of the molded product MP is completed. When the runner portion RP extends from the lens 10 as in the molded product MP of the present embodiment, deformation and stress distortion are likely to occur during mold release and removal. However, in the above mold release process, the lens 10 has its optical axis. Since the mold can be released while maintaining the axis AX of the movable mold 41 and the like, and the speed is controlled, the stress strain remaining in the lens 10 due to the mold release can be reduced. Further, when the mold is opened to move the movable mold 41 backward, if the molded product MP remains embedded in the movable mold 41 side as in the prior art, the second optical surface 11b is more peripheral than the first optical surface 11a of the lens 10. There is a possibility that the lens 10 is warped rapidly due to the temperature, and the lens 10 is first warped from the first transfer surface S1 by releasing the first optical surface 11a of the lens 10 as in the present embodiment. Ten warpage problems can be reduced. Further, since the mold opening for retracting the movable mold 41 and the projection of the lens 10 of the molded product MP are performed in parallel, there is an effect of shortening the lens manufacturing cycle.

  In this state, a take-out device (not shown) is operated to completely separate the molded product MP from the movable mold 41 and carry it out (step S18). When transporting the molded product MP, a portion of the molded product MP excluding the lens 10, specifically, a sprue or runner of the molded product MP is chucked.

  According to the molding die and the optical element manufacturing method of the present embodiment described above, the holding portion 64s includes the first member 51 disposed on the distal end side, and the second member 52 that supports the first member 51. Since the first member 51 has the protruding member 53 that moves the first member 51 from the first position on the root side to the second position on the tip side, the movable mold 41 that is the first mold and the fixed that is the second mold. When the mold is opened to separate the mold 42, the first member 51 is moved from the first position to the second position by the protruding member 53, and the lens 10 of the molded product MP is preliminarily moved to the first transfer surface S1 of the first core portion 64a. Can be released from the mold. Accordingly, the lens 10 can be reliably released from the movable mold 41 which is the first mold, and the lens 10 can be easily taken out between both the molds 41 and 42. It is possible to suppress deformation, scratches, internal stresses, and the like of the lens 10 that is an optical element. Further, since the lens 10 can be released from the first core portion 64a of the movable mold 41, which is the first mold, at an early timing, the molded product MP, that is, the cooling of the lens 10 is greatly increased on the root side and the tip side. Different phenomena can be prevented, and warping deformation can be prevented from occurring in the lens 10 due to a difference in contraction between the root side and the tip side of the lens 10.

  As described above, the present invention has been described based on the embodiment, but the present invention is not limited to the above embodiment. For example, in the above embodiment, the protruding member 53 is a spring coil. However, as shown in FIG. 6, for example, the protruding member 53 may be a rubber-like elastic member having a ring-shaped outer shape.

  Further, as shown in FIGS. 7A and 7B, the first member 51 having a symmetrical shape is changed to a first member 151 having an asymmetric shape over the entire circumference shown in FIG. Provided with a tip 151b that is a circular arc shaped protrusion from which the ring has been partially removed, and changed the shape of the opening OP of the locking member 152a of the second member 52 to that corresponding to the tip 151b. doing. Note that FIG. 7A is a cross-sectional view taken along the line AB of FIG. As in the case shown in the drawing, even when the tip portion 151b is formed in two arcs along the periphery of the first core portion 64a, the lens 10 can be smoothly released as in the case of FIG. Can do. In addition, the number of the front-end | tip parts 151b is not restricted to two, It can be made into three or more.

  Further, as shown in FIGS. 8A and 8B, the first member 51 having a symmetric shape is changed to a first member 251 having an asymmetric shape over the entire circumference shown in FIG. A plurality of shaft-like tip portions 251b separated above are provided, and the shape of the opening OP of the locking member 252a of the second member 52 is changed to a circle corresponding to the tip portion 251b. Further, a plurality of projecting pins 251c extending upward from the base portion 51a of the first member 251 in parallel with the axis AX of the first core portion 64a are provided. The pin 251c passes through an opening provided in a molding portion 252d that is the inner edge of the locking member 252a and forms the flange surface 12a and the like of the lens 10. 8A is a cross-sectional view taken along the line CD in FIG. 8B. As shown in the figure, even if the tip 251b for advancing and retracting the first member 251 when the mold is opened and closed and the pin 251c for protruding the lens 10 when the mold is opened are formed in a pin shape at a plurality of locations, the lens 10 mold release can be performed smoothly. In addition, the number of the front-end | tip parts 251b or the pins 251c is not restricted to four, and can be three or five or more.

  The stroke amount Δt of the first member 51, 151, 251 can be arbitrarily changed by setting the shape of the first member 51, 151, 251 or the second member 52, and is adjusted according to the shape of the lens 10. be able to. The depth at which the lens 10 is embedded in the first member 51 can also be changed as appropriate. For example, about half of the side surface 12 c of the flange portion 12 can be embedded in the first member 51.

  In the above description, the bearing 55 such as a ball bearing is provided between the first member 51 and the like and the second member 52 and the like, but an oil-free bush can be used instead of the ball bearing. Further, the contact surfaces of the first member 51 and the second member 52 can be coated. In short, the slidability and straightness of the first member 51 can be improved by disposing a sliding member and applying a surface treatment.

  As shown in FIG. 9, the removal of the molded product MP is not limited to the type that chucks the sprue of the molded product MP, but can be an adsorption-type extraction device 91 that directly adsorbs the lens 10. In this case, the suction pad 92 of the take-out device 91 comes into contact with the flange portion 12 of the lens 10 and sucks and holds the lens 10.

  In the above description, the lens 10 is an objective lens for an optical pickup device, but other types of lenses can be manufactured by the same device as in FIG.

  In the above embodiment, the optical surface of the lens 10 may be smooth without providing the fine shape FS or the like on the optical surface.

  In the above, the holding part 64 s is provided in the movable mold 41, but the same thing as the holding part 64 s can be provided in the fixed mold 42. Further, the movable mold 41 and the fixed mold 42 can be provided with the same one as the holding portion 64s.

  The molding die 40 is not limited to a horizontal type, but can be a vertical type. That is, the injection molding apparatus 100 is not limited to a horizontal type and can be a vertical type injection molding apparatus.

  DESCRIPTION OF SYMBOLS 10 ... Lens, 11 ... Optical function part, 11a, 11b ... Optical surface, 12 ... Flange part, 12a, 12b ... Flange surface, 40 ... Mold for shaping | molding, 41 ... Movable mold (1st metal mold | die), 42 ... fixed mold (second mold), 51 ... first member, 52 ... second member, 52a ... locking member, 52b ... support member, 53 ... projecting member, 64a ... core part, 64b ... outer peripheral part, 64c ... receiving plate, 64s ... holding portion, 68 ... advance / retreat mechanism portion, 74a ... core portion, 74b ... outer peripheral portion, 74c ... receiving plate, 81 ... opening / closing drive device, 100 ... injection molding device, AX ... shaft, CV ... mold Space, FC ... Channel space, GP ... Gate part, GS ... Gate part, LP ... Lens, MP ... Molded product

Claims (12)

A first mold for molding the first optical surface of the optical element;
A second mold for molding the second optical surface of the optical element,
The first mold has a core part that molds the center side of the optical element, and a holding part that holds the core part and molds the peripheral side of the optical element,
The holding portion is disposed on the distal end side and is movable along the axial direction of the core portion, and is fixed directly or indirectly to the core portion to support the first member. A second member that moves, and a protruding member that moves the first member from the first position on the base side to the second position on the tip side,
Mold for molding.   The first member is disposed at the first position on the root side during molding, and moves from the first position to the second position on the distal end side when the mold is opened to separate the first mold and the second mold. The molding die according to claim 1, wherein:   3. The molding die according to claim 1, wherein the protruding member is an elastic member that is sandwiched between the first member and the second member and expands and contracts. 4.   4. The molding metal according to claim 3, wherein the first member generally supports the peripheral side of the optical element and urges the first member to advance from the first position to the second position. 5. Type.   4. The molding metal according to claim 3, wherein the first member partially supports a peripheral side of the optical element and urges the first member to advance from the first position to the second position. 5. Type.   The molding die according to any one of claims 1 to 5, wherein the first member is held in the second member and slides along the axial direction of the core portion. .   The molding die according to claim 6, wherein the first member is supported by the second member by a sliding portion.   The said 2nd member of the said holding | maintenance part has a locking member which prescribes | regulates the amount of displacement of the axial direction of the said 1st member, and a supporting member which supports the said locking member. The molding die as described in the item. An optical element manufacturing method using a molding die having a first mold for molding a first optical surface of an optical element and a second mold for molding a second optical surface of the optical element. ,
The first mold has a core part that molds the center side of the optical element, and a holding part that holds the core part and molds the peripheral side of the optical element,
The holding portion is disposed on the distal end side and is movable along the axial direction of the core portion, and is fixed directly or indirectly to the core portion to support the first member. A second member that
By moving the first member of the holding portion from the first position on the base side to the second position on the tip side, the optical element is released from the core portion earlier than the holding portion. A method for manufacturing an optical element.   The first member is moved from the first position on the base side to the second position on the tip side when the mold is opened to separate the first mold and the second mold. The manufacturing method of the optical element of Claim 9.   The method of manufacturing an optical element according to claim 9, wherein the first member is moved from the first position to the second position by the protruding member.   11. The method of manufacturing an optical element according to claim 9, wherein the protruding member is an elastic member that expands and contracts between the first member and the second member. .

Images