WO2009122862A1 - Optical element manufacturing method, optical element molding die, and optical element - Google Patents

Abstract

Since an optical element molding die prepared by assembling a core part (62), the base material of which is composed of a low heat conduction material having a heat conductivity of 20 W/m•K or lower, on a movable die (42) is used, melted resin MM filled in cavity CV between a pair of dies (41, 42) can be gradually cooled to a desired degree. Also, a high degree of transfer of the fine pattern FP of a lens OL can be achieved while preventing increased molding cycle time. In addition, in the demolding step, since a movable pin (64) is used to cause the flange part OLb, which is a part of lens OL other than the lens optical plane, to protrude, the central part OLa of lens OL adhered to the core part (62) can be pressed out and separated so that damage to the fine pattern FP can be prevented during demolding to guarantee good demolding properties.

Description

Optical element manufacturing method, optical element molding die, and optical element

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

In recent years, a Blu-ray Disc (BD) that uses a blue-violet laser with a higher density than conventional DVDs and a wavelength of 400 nm or more and 410 nm or less and an image side numerical aperture NA of the objective lens is 0.80 or more. An optical pickup device using such a high storage capacity disk has been put into practical use. The objective lens used for recording or reproducing on a high storage capacity disk using such a blue-violet laser not only supports a short wavelength different from that of the conventional objective lens for DVD, but also more than the conventional objective lens. Higher NA is required.

Furthermore, in addition to this type of BD, in a compatible objective lens that is commonly used for recording or reproduction of, for example, conventional DVDs and CDs, the surface is provided with fine uneven shapes for imparting optical path differences such as diffraction patterns. In order to cope with a plurality of disc standards. However, for such an objective lens, it is necessary to use a blue-violet laser for recording or reproduction of BD and to support a plurality of light beams having different wavelengths in addition to a required NA of 0.80 or more. There is a problem that even a slight shape error reduces the light utilization efficiency of each light beam.

Also, when the NA becomes a high NA of 0.80 or more like an objective lens used at least for recording or reproduction of BD, there is a problem that the decentering of the optical surface greatly affects the coma aberration. For this reason, when mass producing high NA objective lenses, if the decentered state of the optical surface fluctuates and is not stable, there is a problem that the yield rate of the product is lowered and the mass productivity is lacking.

As a method of manufacturing an optical element such as a lens having a fine concavo-convex shape as described above and requiring high precision transfer by injection molding, the mold surface is repeatedly heated and cooled, and the mold cavity surface temperature is repeated. A so-called heat cycle molding that moves up and down is known. In this heat cycle molding, the resin is filled with the mold heated to a temperature higher than the melting temperature of the resin, and after filling the resin, the mold is cooled to solidify the filled resin, and then the resin molded product is taken out. As a result, high transfer to a resin molded product having a cavity surface shape can be realized.

However, high-temperature heating and low-temperature cooling of the mold is necessary, and the equipment becomes larger and more complicated and the manufacturing cost of the optical element is increased, such as supply of the high-temperature medium and low-temperature medium to the mold, repeated switching, and temperature control. Becomes higher. In particular, since it is necessary to repeatedly raise and lower the temperature between high and low temperatures, there is a problem that the time required for molding the optical element, that is, the cycle time is very long. In addition, the productivity is not only deteriorated due to the substantial extension of the molding cycle, but a pair of molding each optical surface of the lens by repeating expansion and contraction of the stationary mold and the movable mold by heating and cooling in the cycle. There is also a problem that the relative position of the nesting varies and the eccentricity is not stable.

On the other hand, as a manufacturing method that does not rely on heat cycle molding, a low thermal conductivity material having a thermal conductivity of a predetermined value or less is used as a base material (base material), and a low hardness material coated on the surface of the base material is cut. There is known a technique in which molding is performed using a molding die provided with a mold member (nesting) on which a molding surface for transferring a fine shape of an optical element is formed (see Patent Document 1). Japanese Patent Application Laid-Open No. 2004-228561 describes that after molding, the mold is separated and the mold is opened, and then the optical element is released from the mold by projecting a mold member (nesting).
JP 2004-284110 A

However, in the manufacturing method of Patent Document 1, since a mold member (nesting) configured using a low heat conductive material as a base material is used, the resin filled in the mold member can be gradually cooled to a desired level. The mold member is sufficiently filled up to the finely shaped tip to enable highly accurate transfer. However, since the optical element is projected by the mold member (nesting), the slide of the mold member for molding the optical surface is performed. There is a problem that the eccentric state of the optical surface is not stable when the optical element is repeatedly molded by the movement.

In addition, after the optical element is protruded by the mold member, the sprue or runner formed at the time of molding is generally gripped by the take-out member and the optical element held by the mold member is peeled off. Although it will be peeled off first from the gate side, the fine shape is transferred to the tip details with high precision by the mold member composed of the low thermal conductive material as the base material. A new problem emerged that the tip of the shape collapsed, resulting in poor releasability. This is different from the conventional case where the tip of the fine shape is not filled with resin and the tip is greatly sagted. It is considered that when the mold member is released from the mold member, the tip of the fine shape strongly contacts the mold member. In particular, in a compatible objective lens compatible with a plurality of disk standards as described above, high-precision transfer of fine shapes and suppression of eccentricity are important problems.

Therefore, the present invention provides a good separation that prevents collapse of the concavo-convex shape without making the molding cycle time longer than necessary in molding an optical element having a concavo-convex shape such as an optical path difference providing structure having a fine shape. An object of the present invention is to provide a method of manufacturing an optical element that can realize high-accuracy transfer while ensuring moldability, and that can stabilize aberration of an optical surface and reduce aberrations even in repeated molding.

Another object of the present invention is to provide an optical element molding die for realizing the above-described optical element manufacturing method, and an optical element molded thereby.

In order to solve the above-mentioned problem, a first optical element manufacturing method according to the present invention is (a) an optical element manufacturing method having an optical function part having an uneven shape on an optical surface and a flange part, (B) A nesting having a transfer surface for transferring the concavo-convex shape and having a base material made of a low thermal conductive material having a thermal conductivity of 20 W / m · K or less is at least one of a fixed mold and a movable mold A molding step of molding an optical element by injection molding using a pair of molds provided in the above, and (c) an optical element molded by using a protruding member while separating the fixed mold and the movable mold And a release step of releasing the optical element by protruding a portion other than the optical surface.

In the above manufacturing method, in the molding step, a nesting provided with a transfer surface for transferring the concavo-convex shape and having a base made of a low thermal conductive material having a thermal conductivity of 20 W / m · K or less is fixed to a fixed metal. Since a pair of molds provided in at least one of a mold and a movable mold is used, the resin filled in the cavity between the pair of molds can be gradually cooled to a desired level without quenching, and molding It is possible to achieve highly accurate transfer of the uneven shape of the optical element while preventing an increase in cycle time. Further, in the above manufacturing method, in the mold releasing step, the optical element is released from the nest having the uneven shape by protruding a part other than the optical surface of the optical element formed using the protruding member. High-precision transfer can be realized by preventing the collapse of the concavo-convex shape and ensuring good releasability. Further, since the protruding member is used to release the insert from the nest having the concavo-convex shape, the eccentric accuracy of the optical surface can be increased as compared with the case where the insert is moved forward and backward to release.

The second optical element manufacturing method according to the present invention is (a) an optical element manufacturing method having an optical function part having an uneven shape on an optical surface and a flange part, and (b) an uneven shape. A heat conduction suppressing layer composed of a low heat conductive material having a heat conductivity of 20 W / m · K or less between a substrate and a surface processing layer that forms the transfer surface. A molding step of molding an optical element by injection molding using a pair of molds provided with at least one of a fixed mold and a movable mold, and (c) the fixed mold and the movable mold And a releasing step of releasing the optical element by protruding a part other than the optical surface of the optical element formed using the protruding member.

Even in the above manufacturing method, the resin filled in the cavity between the pair of molds can be gradually cooled to a desired level without quenching due to the presence of the heat conduction suppressing layer provided in the insert, and the time of the molding cycle It is possible to achieve highly accurate transfer of the uneven shape of the optical element while preventing the increase. Further, in the above manufacturing method, the part other than the optical surface of the optical element formed by using the protruding member is released from the nest having the concavo-convex shape, so that the decentering accuracy of the optical surface is improved while releasing. It is possible to prevent the collapse of the uneven shape of the film and to secure a good releasability and realize a highly accurate transfer.

In a specific aspect or aspect of the present invention, in the above manufacturing method, at least a part of the transfer portion for transferring the shape of the flange portion has a low thermal conductivity of 20 W / m · K or less. It consists of In this case, not only the base material and the low thermal conductive material but also the transfer part for the flange part provided on the peripheral side (hereinafter also referred to as “flange forming part”) can be managed, so a pair of molds The rapid cooling of the resin filled in the cavity between them can be suppressed, and the cooling rate of the optical element can be adjusted more precisely.

In another aspect of the present invention, at least a part of the protruding member is made of a low thermal conductive material having a thermal conductivity of 20 W / m · K or less. In this case, rapid heat dissipation by the protruding member can be prevented, and rapid cooling of the resin filled in the cavity between the pair of molds can be suppressed.

Thus, when at least a part of the protruding member is made of a low heat conductive material, at least a part of the transfer part for transferring the shape of the flange part may be made of a low heat conductive material. On the other hand, the transfer part for the flange part is not made of a low heat conductive material, and the protrusion member is made of a low heat conductive material, thereby further preventing the molding cycle time from being prolonged while ensuring high transfer. Can do. Further, at this time, when the base material of the flange portion is made of a low heat conductive material such as ceramic, it is preferable because it is difficult to process a complicated shape of the transfer portion for the flange portion and the cost is increased.

In yet another aspect of the present invention, the projecting member includes a plurality of members projecting portions other than the optical surface of the molded optical element, and the gate formed when molding the optical element among the plurality of members. The member protruding from the near side and the member protruding from the side away from the gate are formed of materials having different thermal conductivities. In this case, the slow cooling of the molten resin can be finely adjusted between the side close to the gate and the side away from the gate.

At this time, if the member protruding from the side away from the gate is formed of a material having lower thermal conductivity than the member protruding from the side closer to the gate, the ease of cooling the molten resin on the side away from the gate is reduced. As a result, substantially uniform cooling can be performed for the entire optical element. Thereby, it is possible to suppress aberration deterioration due to surface shape accuracy error, and it is possible to obtain an optical element suitable for an objective lens for an optical pickup device having an NA of 0.80 or more.

In still another aspect of the present invention, the protruding member is a member that transfers a part of the shape of the flange part and protrudes a part of the flange part, and transfers the shape of the flange part. Of these, the transfer portion excluding the portion transferred by the protruding member and the protruding member are formed of materials having different thermal conductivities. In this case, it is possible to adjust the time of the molten resin cooling or molding cycle. For example, by adjusting the area of the tip surface of the protruding member that transfers a part of the flange portion, the molten resin cooling or molding cycle In addition to adjusting the time, the optical performance such as astigmatism can be controlled.

In still another aspect of the present invention, the movable mold includes a base made of a low heat conductive material or a nesting having a heat conduction suppressing layer. In this case, the concavo-convex shape can be transferred to the optical element by the nesting transfer surface provided on the movable mold side, and high transfer of the concavo-convex shape can be achieved by releasing with the protruding member.

In still another aspect of the present invention, the fixed mold includes a base made of a low heat conductive material or a nesting having a heat conduction suppressing layer. In this case, the concavo-convex shape can be transferred to the optical element by the nesting transfer surface provided on the fixed mold side, and when the protruding member is opened between the fixed mold and the movable mold, the concavo-convex shape of the optical element can be transferred. High transfer of such irregularities can be achieved without affecting the collapse.

In still another aspect of the present invention, the optical element is a lens. In this case, a high-precision and high-performance lens having a fine uneven shape such as a diffraction pattern, for example, an objective lens for an optical pickup can be provided.

The first optical element molding die according to the present invention is (a) an optical element molding mold for molding an optical element by a pair of molds, and (b) at least one of the pair of molds is: A nesting having a transfer surface for transferring the concavo-convex shape and having a base material made of a low thermal conductive material having a thermal conductivity of 20 W / m · K or less, (c) a mold member for supporting the nesting, d) A protruding member that releases the optical element by protruding a part other than the optical surface of the optical element formed when the pair of molds are separated from each other.

Since the optical element molding die includes a nesting in which a base material is composed of a low thermal conductive material, the resin filled in the cavity between the pair of molds can be gradually cooled to a desired level, and a molding cycle can be performed. It is possible to achieve high transfer of the concave and convex shape of the optical element while preventing the increase in time. In addition, since the optical element molding die includes a protruding member that is released by protruding a portion other than the optical surface of the molded optical element, the unevenness of the concave and convex shape at the time of releasing is lost while improving the decentering accuracy of the optical surface. It is possible to achieve high-accuracy transfer while ensuring good releasability.

The second optical element molding die according to the present invention is (a) an optical element molding die for molding an optical element by a pair of molds, and (b) at least one of the pair of molds is: Heat transfer suppression comprising a transfer surface for transferring irregularities, and comprising a low thermal conductivity material having a thermal conductivity of 20 W / m · K or less between the surface processed layer forming the transfer surface and the substrate A nest having a layer; (c) a mold member that supports the nest; and (d) a portion other than the optical surface of the optical element formed when the pair of molds are separated from each other, thereby separating the optical element. A protruding member to be molded.

Since the optical element molding die includes a nesting having a heat conduction suppressing layer made of a low heat conductive material, the resin filled in the cavity between the pair of dies can be gradually cooled to a desired level. Further, it is possible to achieve high transfer of the uneven shape of the optical element while preventing the molding cycle time from increasing. In addition, the optical element molding die includes a protruding member that is released by protruding a part other than the optical surface of the optical element, so that the eccentricity of the optical surface is improved and the uneven shape at the time of releasing is prevented from collapsing. As a result, it is possible to secure a good releasability and realize a highly accurate transfer.

The optical element according to the present invention is formed using the optical element molding die described above. In this case, the optical element can be formed by using the above-described optical element molding die, so that the concavo-convex shape transferred well can be formed with less eccentricity. Specifically, high-precision, high-performance, high-NA objective lenses for BD, or compatible high-precision, high-performance, high-NA objective lenses that support multiple disc standards for BD, DVD, and CD, etc. Can be provided.

In the above, it is more preferable that the low thermal conductive material is a low thermal conductive material of 10 W / m · K or less in order to exhibit the effect of gradually cooling the fine uneven shape and realizing high-precision transfer. In particular, high-accuracy transfer can be realized even for an objective lens having a fine concavo-convex shape on an optical surface (deep optical surface) having a large curvature, such as an objective lens having a high NA of NA 0.80 or more. Moreover, it is preferable that a low heat conductive material is 0.05 W / m * K or more. Examples of the low heat conductive material include metal, ceramic, resin, glass, and the like.

In this specification, an optical surface refers to a region that functions effectively as an optical surface. Further, the concavo-convex shape refers to a structure having a function of imparting an optical path difference to incident light, such as a shape having a fine step such as a diffraction pattern. Moreover, the base material of the nesting means an essential part (base material) constituting the nesting.

Further, in the present specification, the surface processed layer is a layer for providing an uneven shape, and refers to a layer whose surface has been processed into a desired shape with a diamond bite after being coated with a plating layer or the like. . In addition, the surface of the nesting may further have a protective layer or a release layer on the surface processed layer.

The protruding member is composed of a plurality of pins, blocks, sleeve-like members, and the like. It is preferable that the protruding member protrudes the optical element along the mold opening direction, and the tip of the portion other than the optical surface is annular over the periphery of the optical surface so that the optical surface is symmetrical and the substantially uniform protrusion is performed. The center of the optical surface is the center when the protruding member is composed of a plurality of members, or when the tip of the protruding member is in contact with a portion other than the optical surface at a plurality of locations. It is more preferable that these are arranged symmetrically and protruded.

It is a fragmentary sectional side view explaining the structure of the optical element shaping | molding die comprised with a fixed metal mold | die and a movable metal mold | die. It is a partial expanded sectional view of FIG. It is an R arrow end view of the movable metal mold | die shown in FIG. FIG. 2 is an enlarged side view of a lens that is injection-molded by the mold of FIG. 1. It is a front view explaining the shaping | molding apparatus incorporating the optical element shaping die shown in FIG. It is a flowchart explaining operation | movement of the shaping | molding apparatus of FIG. It is a conceptual diagram explaining the mold release in the optical element shaping die shown in FIG. It is sectional drawing explaining the metal mold | die and manufacturing method of 2nd Embodiment. It is sectional drawing explaining the metal mold | die and manufacturing method of 3rd Embodiment. It is sectional drawing explaining the metal mold | die and manufacturing method of 4th Embodiment. It is sectional drawing explaining the metal mold | die and manufacturing method of 5th Embodiment. It is sectional drawing explaining the metal mold | die and manufacturing method of 6th Embodiment. It is sectional drawing explaining the metal mold | die and manufacturing method of 7th Embodiment. It is sectional drawing explaining the metal mold | die and manufacturing method of 8th Embodiment. It is sectional drawing explaining the metal mold | die and manufacturing method of 9th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Movable board 12 ... Fixed board 15 ... Opening / closing drive device 16 ... Injection apparatus 30 ... Control apparatus 41 ... Fixed mold 42 ... Movable mold 46 ... Mold temperature controller 51 ... Outer peripheral type 51a ... End face 52,252 ... Core Part 53 ... Mounting plate 56a ... Optical surface molding surface 56b ... Molding surface 61, 361 ... Peripheral die 61a ... End surface 62, 262, 461 ... Core part 63 ... Mounting plate 64 ... Movable pin 64, 364 ... Movable pin 65b ... Pin insertion Hole 66a ... Optical surface molding surface 66b ... Molding surface 67,267 ... Nickel phosphorus plating layer 68 ... Advancing / retracting mechanism 81 ... Extrusion mechanism 100 ... Molding device 162c ... Heat conduction suppression layer AX ... Shaft F1 ... Flange surface F2 ... Flange surface FC ... Flow path space FF ... Flange forming part FM ... Flange forming part FP ... Fine shape GT ... Gate MM ... Molten resin MP ... Resin molded product OL ... Lens OLa Center OLB ... flange portion SS ... microstructure Sa ... optical surface Sb ... optical surface

[First Embodiment]
Hereinafter, an optical element molding die and a method for manufacturing an optical element according to a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a partial sectional side view for explaining the structure of an optical element molding die composed of a fixed die and a movable die. FIGS. 2 (A) to 2 (C) are P1 parts in FIG. FIG. 3 is an arrow view of the movable mold shown in FIG. 2A viewed from the R direction. FIG. 4 is an enlarged side view of a lens that is injection-molded by the mold shown in FIG.

The fixed mold 41 and the movable mold 42 can be opened and closed with the parting line PL as a boundary. A cavity CV, which is a space between both molds 41 and 42, corresponds to the shape of a lens OL (see FIG. 4 and the like) as an optical element that is a molded product. The lens OL is made of plastic and includes a center portion OLa as an optical function portion having an optical function, and an annular flange portion OLb extending from the center portion OLa in the outer diameter direction. The lens OL is an objective lens for an optical pickup device, is compatible with BD, DVD, and CD, and satisfies NA 0.85 with respect to a light beam having a wavelength for BD.

The fixed die 41 includes a core portion 52 as a nesting on the fixed side, an outer peripheral die 51 having a structure capable of supporting and fixing the nesting on the fixed side, and the outer peripheral die 51 and the core portion 52. And a mounting plate 53 that is integrally fixed. Here, the outer peripheral mold 51 and the mounting plate 53 are mold members that hold the core 52 as a nesting from the periphery.

The outer peripheral mold 51 has an end face 51a that forms a parting line PL. Further, a flange forming portion FF is provided at the tip of the outer peripheral mold 51, and a molding surface 56b for defining a cavity CV is formed on the surface of the flange forming portion FF. The molding surface 56b is a transfer surface for molding the flange surface F1 of the flange portion OLb of the lens OL, that is, one annular end surface. In addition, a core insertion hole 55 that is a cylindrical through hole that supports the core portion 52 is formed inside the outer peripheral mold 51.

The core portion 52 has a cylindrical outer peripheral side surface that can be fitted into the core insertion hole 55, and an optical surface for defining a cavity CV is provided at the distal end surface provided at the distal end portion 52 b of the core portion 52. A molding surface 56a is provided. The optical surface molding surface 56a is a concave surface and is a transfer surface that molds one optical surface Sa of the center portion OLa of the lens OL.

In the fixed mold 41, the outer peripheral mold 51 is made of a high thermal conductivity material having a thermal conductivity higher than 20 W / m · K, such as pre-hardened steel, that is, low carbon steel (thermal conductivity: 60.0 W / m · K). It is configured. Moreover, the core part 52 is also comprised with the base material of the high heat conductive material whose heat conductivity is larger than 20 W / m * K, specifically, low carbon steel or stainless steel. The end surface of the core portion 62 on the cavity CV side can be covered with a nickel phosphorus plating layer formed by using an electroless nickel plating method, and the optical surface molding surface 56a is formed by this nickel phosphorus plating layer. Can do. Furthermore, the optical surface molding surface 56a can be coated with a thin release film formed of a resin-based material.

The movable mold 42 includes a core portion 62 as a movable-side core mold, an outer peripheral mold 61 having a structure capable of supporting and fixing the movable-side core mold, and the outer peripheral mold 61 and the core. A mounting plate 63 for fixing the part 62 integrally, a movable pin 64 as a protruding member that protrudes and releases the lens OL, and an advance / retreat mechanism 68 for moving the movable pin 64 forward and backward relative to the fixed mold 41; Is provided. Here, the outer peripheral mold 61 and the mounting plate 63 are mold members that hold the core portion 62 as a nesting from the periphery. The movable mold 42 is movable along the axis AX and opens and closes with respect to the fixed mold 41.

In addition, the outer periphery type | mold 61 is comprised with the high heat conductive material whose heat conductivity is larger than 20 W / m * K, for example, prehardened steel, ie, low carbon steel. On the other hand, the core portion 62 is made of a lower heat conductive material than the outer peripheral die 61. The base material of the core portion 62, that is, the low thermal conductivity material constituting the base material has a thermal conductivity of 0.05 W / m · K or more and 20 W / m · K or less. For example, 6-4Ti is used as the base material. be able to.

The outer periphery type | mold 61 has the end surface 61a which forms the parting line PL. In addition, a core insertion hole 65 for supporting the core portion 62 and a pin insertion hole 65 b for supporting the movable pin 64 are formed inside the outer peripheral mold 61. Here, the core insertion hole 65 is a columnar through hole, and the pin insertion hole 65b is a smaller diameter through hole. A flange forming portion FM is provided at the tip of the outer peripheral mold 61, and a molding surface 66b for defining the cavity CV is formed on the surface of the flange forming portion FM. The molding surface 66b is a transfer surface for molding the flange surface F2 of the flange portion OLb of the lens OL, that is, one annular end surface.

The core portion 62 has a cylindrical outer peripheral side surface that can be fitted into the core insertion hole 65, and an optical surface for defining a cavity CV is provided on the distal end surface provided at the distal end portion 62 b of the core portion 62. A molding surface 66a is provided. The optical surface molding surface 66a is a concave surface and is a transfer surface for molding one optical surface Sb of the center portion OLa of the lens OL. The end surface of the core portion 62 on the cavity CV side is covered with a nickel phosphorous plating layer 67 formed using an electroless nickel plating method in order to improve machinability. Thus, an optical surface molding surface 66 a is formed as the surface of the nickel phosphorus plating layer 67. Furthermore, the optical surface molding surface 66a can be coated with a thin release film formed of a resin-based material. Although not shown in the drawing, a spacer can be interposed between the base side end surface of the core portion 62 and the front surface of the mounting plate 63. Thereby, the space | interval of the optical surface molding surface 66a of the core part 62 and the optical surface molding surface 56a of the core part 52 which opposes this can be adjusted now.

The movable pin 64 is inserted into the pin insertion hole 65b and is movable along the axis AX within the pin insertion hole 65b. That is, the movable pin 64 can be driven by the advance / retreat mechanism 68 to advance toward the fixed mold 41 or retract toward the opposite side within the pin insertion hole 65 b of the outer peripheral die 61. The tip of the pin insertion hole 65b constitutes a part of the molding surface 66b that defines the cavity CV. As shown in FIG. 3, four movable pins 64 are arranged at equal intervals along the annular molding surface 66b of the outer peripheral die 61, and push out the flange portion OLb of the lens OL along the axis AX in a balanced manner. Is possible.

Note that the number of movable pins 64 is not limited to four, and may be various numbers of three or more according to specifications such as the size of the lens OL and allowable accuracy. The movable pin 64 can be a block-shaped member. Further, instead of the movable pin 64, a sleeve-like protruding member that can push out the flange surface F2 of the flange portion OLb may be disposed around the core portion 62 and reciprocated along the axis AX.

The advancing / retracting mechanism 68 includes a flange-shaped rear end portion 72 provided at the rear end portion of the movable pin 64, a return spring 73 held between the rear end portion 72 and the mounting plate 63, and the rear end portion 72. And a pin drive plate 74 that supports and moves back and forth in the axial direction. Since the return spring 73 urges the movable pin 64 rearward, the movable pin 64 receives an urging force held in a retracted state, and protrudes by a necessary amount in response to the force from the pin drive plate 74. The pin drive plate 74 is driven by an ejector of an injection molding machine, which will be described later, and is displaced along the axis AX by a distance necessary for mold release at an appropriate timing.

FIG. 5 is a front view illustrating a molding apparatus for carrying out the manufacturing method of the present embodiment. The illustrated molding apparatus 100 includes an injection molding machine 10 that is a main body part that performs injection molding to produce a resin molded product MP, a take-out device 20 that is an accessory part that takes out the resin molded product MP from the injection molding machine 10, and molding. And a control device 30 that comprehensively controls the operation of each unit constituting the device 100.

The injection molding machine 10 includes a movable platen 11, a fixed platen 12, a mold clamping plate 13, an opening / closing drive device 15, and an injection device 16. The injection molding machine 10 enables molding by sandwiching a movable mold 42 and a fixed mold 41 between the movable platen 11 and the fixed platen 12 and clamping both molds 41 and 42.

The movable platen 11 is supported by the slide guide 15a so as to be movable back and forth with respect to the fixed platen 12. The movable platen 11 detachably supports the movable mold 42. In addition, an ejector 45 is incorporated in the movable platen 11. The ejector 45 is a part for operating the advance / retreat mechanism 68 shown in FIG. Further, the ejector 45 pushes the movable pin 64 so as to push the resin molded product MP in the movable mold 42 toward the fixed mold 41, and enables the ejector 20 to transfer the resin molded product MP. The resin molded product MP includes a plurality of lenses OL shown in FIG. 4, and the plurality of lenses OL are connected to each other via sprues and runners (not shown) that are formed at the time of molding. Yes.

The fixed platen 12 is fixed to the center of the support frame 14 so as to face the movable platen 11, and supports the take-out device 20 on the top thereof. The stationary platen 12 detachably supports the stationary mold 41. The fixed platen 12 is fixed to the mold clamping machine 13 via a tie bar so that it can withstand the pressure of mold clamping at the time of molding.

The mold clamping machine 13 is fixed to the end of the support frame 14. The mold clamping machine 13 supports the movable board 11 from the back via the power transmission part 15d of the opening / closing drive device 15 at the time of mold clamping.

The opening / closing drive device 15 includes a slide guide 15a, a power transmission unit 15d, and an actuator 15e. The slide guide 15a supports the movable platen 11 and enables a smooth reciprocating movement in the advancing and retreating direction with respect to the fixed platen 12. The power transmission unit 15 d expands and contracts by receiving a driving force from an actuator 15 e that operates under the control of the control device 30. As a result, the movable platen 11 moves forward and backward freely with respect to the mold clamping plate 13, and as a result, the movable platen 11 and the fixed platen 12 are moved close to and away from each other, and the fixed mold 41 is moved. Clamping and mold opening with the movable mold 42 are performed.

The injection device 16 includes a cylinder 16a, a raw material storage unit 16b, a screw drive unit 16c, and the like. The injection device 16 operates at an appropriate timing under the control of the control device 30, and can inject molten resin from the resin injection nozzle 16d in a temperature-controlled state. In the state where the fixed mold 41 and the movable mold 42 are clamped, the injection device 16 brings the resin injection nozzle 16d into contact with the opening of the sprue provided in the fixed mold 41, and the flow path space FC (see FIG. 1). On the other hand, the molten resin in the cylinder 16a can be supplied at a desired timing.

The take-out device 20 includes a hand 21 that can hold the resin molded product MP and a three-dimensional drive device 22 that moves the hand 21 three-dimensionally. The take-out device 20 operates at an appropriate timing under the control of the control device 30, and after the mold is opened with the fixed mold 41 and the movable mold 42 separated from each other, the resin molded product remaining in the movable mold 42 It has the role of holding the MP and carrying it out.

The control device 30 includes an opening / closing control unit 31, an injection device control unit 32, an ejector control unit 33, and a take-out device control unit 34. The opening / closing control unit 31 enables the molds 41 and 42 to be clamped and opened by operating the actuator 15e. The injection device controller 32 causes the resin to be injected at a desired pressure into the cavity formed between the molds 41 and 42 by operating the screw driver 16c and the like. The ejector control unit 33 operates the ejector 45 to push out the resin molded product MP remaining in the movable mold 42 when the mold is opened from the movable mold 42. The take-out device control unit 34 operates the take-out device 20 to grip the resin molded product MP remaining in the movable mold 42 after mold opening and mold release and carry it out of the injection molding machine 10.

The mold temperature controller 46 circulates a temperature-controlled heat medium through jackets (not shown) formed in the molds 41 and 42. Thereby, the temperature of both metal mold | dies 41 and 42 can be kept at an appropriate temperature at the time of shaping | molding. At this time, the temperature of both molds 41 and 42 can be monitored by a temperature sensor (not shown) embedded in both molds 41 and 42.

FIG. 6 is a flowchart conceptually illustrating the operation of the molding apparatus 100 shown in FIG. First, the mold temperature controller 46 heats both molds 41 and 42 to a temperature suitable for molding (step S10). Thereby, the temperature of the surface of the mold part which forms the cavity CV in both the molds 41 and 42 or the temperature in the vicinity thereof is, for example, 50 ° C. lower than the glass transition temperature of the molten resin supplied from the injection device 16. The temperature is kept below 10 ° C. higher than the glass transition temperature.

Next, the opening / closing drive device 15 is operated to move the movable platen 11 forward to start mold closing (step S11). By continuing the closing operation of the opening / closing drive device 15, the movable platen 11 moves to the fixed platen 12 side to the die contact position where the fixed die 41 and the movable die 42 come into contact with each other, and the die closing is completed. By further continuing the closing operation of the device 15, mold clamping is performed to clamp the fixed mold 41 and the movable mold 42 with necessary pressure (step S12).

Next, in the injection molding machine 10, the injection device 16 is operated to inject the molten resin into the cavity CV between the fixed mold 41 and the movable mold 42 that are clamped at a required pressure. (Step S13). The injection molding machine 10 maintains the resin pressure in the cavity CV.

After the molten resin is introduced into the cavity CV, as shown in FIG. 2 (A), the molten resin in the cavity CV is gradually cooled by heat dissipation, so that the molten resin is solidified with the cooling and the molding is completed. It waits to do (step S14). At this time, since the base material of the core portion 62 is composed of a low thermal conductivity material having a thermal conductivity of 0.05 W / m · K or more and 20 W / m · K or less, the fineness formed on the optical surface molding surface 66a The molten resin MM can be filled to the back of the structure SS (see FIG. 7A). In addition, in the above cooling, it is preferable not to cool both the molds 41 and 42 actively. Thereby, it is possible to prevent the temperature control from becoming complicated and the energy consumption from being increased during reheating with a high-temperature medium. Further, when the cavity CV is filled with the resin in order to mold the next resin molded product, it is possible to prevent the molding cycle time from becoming long by heating the injection mold again.

Next, in the injection molding machine 10, as shown in FIG. 2B, the opening / closing drive device 15 is operated to open the mold to retract the movable platen 11 (step S15). Along with this, the movable mold 42 moves backward, and the fixed mold 41 and the movable mold 42 are separated. As a result, the resin molded product MP, that is, the lens OL is released from the fixed mold 41 while being held by the movable mold 42.

Next, in the injection molding machine 10, as shown in FIG. 2C, the ejector 45 is operated to cause the resin molded product MP to be ejected by the movable pin 64 (step S16). Specifically, the four movable pins 64 are projected at the same time, and the flange portion OLb of the lens OL is pushed out along the axis AX with good balance. As a result, the lens OL of the resin molded product MP is urged toward the distal end surface of the movable pin 64 and pushed out toward the fixed mold 41, and the resin molded product MP as the lens OL is released from the movable mold 42. Is done. At this time, since the lens OL is pushed out without being inclined along the axis AX, as shown in FIG. 7B, the fine shape FP as the concavo-convex shape provided on the optical surface Sb of the lens OL is deformed. It is maintained in a precise shape. FIG. 7C is a view for comparison, and shows a case where the center portion OLa of the lens OL is projected using the core portion 62. In this case, when the core is moved back to retreat the core portion 62, the mold is released first from the gate side. Therefore, the fine shape FP is collapsed, and there is a tendency for a releasability defect that the deformed portion DP is formed at the tip. It will occur.

Finally, the take-out device 20 is operated, and the pin drive plate 74 driven by the ejector 45 and the resin molded product MP protruding by the movable pin 64 are gripped by the hand 21 and taken out to the outside (step) S17).

According to the manufacturing method of the first embodiment described above, in the molding step, the core portion in which the base material is configured with a low thermal conductive material having a thermal conductivity of 0.05 W / m · K or more and 20 W / m · K or less. Since the optical element molding die in which 62 is assembled to the movable die 42 is used, the molten resin MM filled in the cavity CV between the pair of dies 41 and 42 can be gradually cooled to a desired degree, and molding is performed. High transfer of the fine shape FP of the lens OL can be achieved while preventing an increase in cycle time. In the above manufacturing method, the mold OL is released by protruding the flange portion OLb as a portion other than the optical surface of the lens OL using the movable pin 64 in the mold releasing step. The center portion OLa can be extruded from the core portion 62 by pushing out the axis AX, and the fine shape FP can be prevented from collapsing at the time of release to ensure good release properties. In addition, since the movable pin 64 is used at the time of protrusion, the eccentric accuracy of the optical surface Sb can be increased as compared with the case where the core part 62 is advanced and retracted.

[Second Embodiment]
Hereinafter, an optical element molding die and an optical element manufacturing method according to the second embodiment will be described. The molding die and the manufacturing method according to the second embodiment are modifications of the first embodiment, and parts that are not particularly described are the same as those of the first embodiment.

FIG. 8A is a partial enlarged cross-sectional view of the fixed mold 41 and the movable mold 42 in the present embodiment, and shows a mold closed state and a mold clamped state. FIG. 8B shows a state in which the lens OL is protruded after the fixed mold 41 and the movable mold 42 are opened.

As shown in FIG. 8, a heat conduction suppressing layer 162 c made of a low heat conductive material is provided at the distal end portion 62 b of the core portion 62. The heat conduction suppressing layer 162c is sandwiched between the nickel phosphorus plating layer 67 which is a surface processed layer and the base material portion 162d which is a base material, and has a role of preventing rapid cooling of the lens OL being molded. .

Specifically, the heat conduction suppressing layer 162c is made of a low heat conductive material having a thermal conductivity of 0.05 W / m · K or more and 20 W / m · K or less. For example, a metal material such as 6-4Ti, It can be formed using a resin material such as polyimide, or a ceramic such as zirconia or alumina. On the other hand, the base material portion 162d is made of a high heat conductive material having a thermal conductivity higher than 20 W / m · K, specifically, a base material of low carbon steel or stainless steel.

Also in this embodiment, similarly to the first embodiment, the molten resin filled in the cavity CV between the pair of molds 41 and 42 can be gradually cooled to a desired level, thereby increasing the time of the molding cycle. It is possible to achieve high transfer of the fine shape FP of the lens OL while preventing it. Also in this embodiment, since the mold release is performed by using the movable pin 64 to project the flange part OLb as a part other than the optical surface of the lens OL, it is possible to prevent the fine shape FP from collapsing during the mold release. Can be secured.

[Third Embodiment]
Hereinafter, an optical element molding die and a method for manufacturing the optical element according to the third embodiment will be described. The molding die and the manufacturing method according to the third embodiment are modifications of the first embodiment, and parts that are not particularly described are the same as those of the first embodiment.

FIG. 9A is a partially enlarged cross-sectional view of the fixed mold 41 and the movable mold 42 in the present embodiment, and shows a mold closed state and a mold clamped state. FIG. 9B shows the open state of the fixed mold 41 and the movable mold 42, and FIG. 9C shows the state in which the lens OL as an optical element protrudes from the movable mold 42. Yes.

As shown in FIG. 9, the cavity CV side end surface of the core portion 252 of the fixed mold 41 is covered with a nickel phosphorous plating layer 267, and the fine structure having an uneven shape by surface processing of the nickel phosphorous plating layer 267. An optical surface molding surface 56a provided with SS is formed as a transfer surface.

Correspondingly, in the fixed mold 41, the base material of the core part 252 is made of a low heat conductive material, and in the movable mold 42 facing, the base material of the core part 262 is made of a high heat conductive material. Yes. The base material of the core portion 252 on the fixed mold 41 side, that is, the low thermal conductivity material constituting the base material has a thermal conductivity of 0.05 W / m · K or more and 20 W / m · K or less. For example, 6-4Ti can be used as a base material. On the other hand, the base material of the core part 262 on the movable mold 42 side, that is, the high thermal conductivity material constituting the base material is a high thermal conductivity material having a thermal conductivity higher than 20 W / m · K, such as pre-hardened steel, that is, low carbon steel, etc. It consists of

In the case of this embodiment, when the mold is opened, as shown in FIG. 9 (B), the movable mold 42 moves backward, and the fixed mold 41 and the movable mold 42 are separated from each other. At this time, the lens OL is released from the fixed mold 41 while being held by the movable mold 42. Thereafter, as shown in FIG. 9C, the lens OL is projected from the movable mold 42 by causing the movable pin 64 to project the lens OL.

Also in the present embodiment, the molten resin filled in the cavity CV between the pair of molds 41 and 42 can be gradually cooled to a desired level, and the center of the lens OL can be prevented while increasing the molding cycle time. High transfer of the fine shape FP of the portion OLa can be achieved. In the present embodiment, the lens OL is released from the fixed mold 41 including the core portion 252 having the optical surface molding surface 56a for transferring the microstructure SS, and the core having the uneven shape. Since the lens OL is not protruded by the portion 252, the decentered state of the optical surface of the center portion OLa hardly changes even if it is repeatedly molded, and stable optical performance can be easily maintained. Further, when the fixed mold 41 and the movable mold 42 are separated from each other, it is possible to prevent the core portion 252 from being displaced or vibrated out of the separation direction and damaging the fine shape FP. As a result, it is possible to obtain a lens OL such as a high NA objective lens that can suppress coma and realize high-accuracy transfer.

[Fourth Embodiment]
The optical element molding die and the optical element manufacturing method according to the fourth embodiment will be described below. Note that the molding die and the manufacturing method according to the fourth embodiment are modifications of the third embodiment, and parts that are not particularly described are the same as those of the third embodiment.

FIG. 10A is a partial enlarged cross-sectional view of the fixed mold 41 and the movable mold 42 in the present embodiment, and shows a mold closed state and a mold clamped state. 10B shows the open state of the fixed mold 41 and the movable mold 42, and FIG. 10C shows the state where the lens OL protrudes from the movable mold 42. FIG.

In the fixed mold 41 shown in FIG. 10, the base material of the core portion 252 is made of a low heat conductive material, and in the movable mold 42 facing the base material of the core portion 262, the high heat conductive material is made. Further, the end surface on the cavity CV side of the core portion 252 of the fixed mold 41 is covered with a nickel phosphorus plating layer 267.

Furthermore, a plurality of protruding mechanisms 81 are provided in the outer peripheral mold 51 of the fixed mold 41 so as to be embedded in an appropriate arrangement. Each protrusion mechanism 81 includes a movable pin 81a that is a protrusion member, a spring 81b that urges the movable pin 81a toward the movable mold 42, and a storage hole 81c that can store the movable pin 81a behind the end surface 51a. Prepare.

Also in this embodiment, when the mold is opened, as shown in FIG. 10 (B), the movable mold 42 moves backward, and the fixed mold 41 and the movable mold 42 are separated from each other. At this time, the lens OL is released from the fixed mold 41 while being held by the movable mold 42. Since the lens OL is pushed out to the movable mold 42 side by the protrusion mechanism 81, the release of the lens OL becomes stable and reliable. Thereafter, as shown in FIG. 10C, the lens OL is protruded from the movable mold 42 by causing the movable pin 64 to project the lens OL.

In the present embodiment, similarly to the third embodiment, the molten resin filled in the cavity CV between the pair of molds 41 and 42 can be gradually cooled to a desired level, thereby preventing an increase in molding cycle time. However, high transfer of the fine shape FP of the central portion OLa of the lens OL can be achieved. Further, the decentered state of the optical surface of the center portion OLa of the lens OL is difficult to change, stable optical performance can be easily maintained, and the core portion 252 shifts or vibrates out of the separation direction, thereby causing a fine shape FP. Can be prevented from being damaged. Further, in the present embodiment, the mold part is released by protruding the flange part OLb as a part other than the optical surface of the lens OL from the core part 252 using the movable pin 81a and the like, so that it corresponds to the microstructure SS at the time of mold release. It is possible to more reliably prevent the fine shape FP from collapsing and to ensure good releasability.

[Fifth Embodiment]
Hereinafter, an optical element molding die and a method for manufacturing the optical element according to the fifth embodiment will be described. The molding die and the manufacturing method according to the fifth embodiment are modifications of the first embodiment, and parts that are not particularly described are the same as those of the first embodiment.

FIG. 11A is a partially enlarged cross-sectional view of the fixed mold 41 and the movable mold 42 in the present embodiment, and shows a mold closed state and a mold clamped state. FIG. 11B shows a state in which the lens OL is protruded after the fixed mold 41 and the movable mold 42 are opened.

The base material of the outer periphery type | mold 361 and the movable pin 364 shown in FIG. 11 is comprised with the low heat conductive material, and the low heat conductive material which comprises such a base material has thermal conductivity 0.05W / m * K or more and 20W. For example, 6-4Ti can be used as a base material. In the present embodiment, the transfer surface for transferring the shape of the flange surface F2 of the flange portion OLb, that is, the molding surface 66b, is formed by a transfer portion that combines the distal end portion of the outer peripheral die 361 and the distal end portion of the movable pin 364. The

In the case of this embodiment, since the outer peripheral mold 361 and the movable pin 364 tend to block heat dissipation, the molten resin filled in the cavity CV between the pair of molds 41 and 42 can be cooled gradually. High transfer of the fine shape FP corresponding to the fine structure SS can be achieved more reliably.

[Sixth Embodiment]
Hereinafter, an optical element molding die and a method for manufacturing the optical element according to the sixth embodiment will be described. The molding die and the manufacturing method according to the sixth embodiment are modifications of the fifth embodiment, and parts that are not particularly described are the same as those of the fifth embodiment.

FIG. 12A is a partially enlarged cross-sectional view of the fixed mold 41 and the movable mold 42 in the present embodiment, and shows a mold closed state and a mold clamped state. FIG. 12B shows a state in which the lens OL is protruded after the fixed mold 41 and the movable mold 42 are opened.

The base material of the tip 461a of the outer peripheral mold 461 and the movable pin 364 shown in FIG. 12 is made of a low heat conductive material, and the low heat conductive material constituting such a base material has a heat conductivity of 0.05 W / m. It has a thermal conductivity of not less than K and not more than 20 W / m · K. For example, 6-4Ti can be used as a base material. The main body portion 361b of the outer peripheral mold 461 is made of a high heat conductive material having a thermal conductivity higher than 20 W / m · K, specifically, a base material of low carbon steel or stainless steel. Here, the transfer portion formed by the tip portion 461a of the outer peripheral mold 461 and the movable pin 364 forms a transfer surface for transferring the shape of the flange surface F2 of the flange portion OLb, that is, a forming surface 66b.

[Seventh Embodiment]
Hereinafter, an optical element molding die and a method for manufacturing the optical element according to the seventh embodiment will be described. Note that the molding die and the manufacturing method according to the seventh embodiment are modifications of the fifth embodiment, and parts that are not particularly described are the same as those of the fifth embodiment.

FIG. 13A is a partially enlarged cross-sectional view of the fixed mold 41 and the movable mold 42 in the present embodiment, and shows a mold closed state and a mold clamped state. FIG. 13B shows a state in which the lens OL is protruded after the fixed mold 41 and the movable mold 42 are opened.

The base material of each movable pin 364 shown in FIG. 13 is made of a low heat conductive material, and the low heat conductive material constituting such a base material has a thermal conductivity of 0.05 W / m · K or more and 20 W / m · For example, 6-4Ti can be used as a base material. In addition, the outer periphery type | mold 61 is comprised with the high heat conductive material with a heat conductivity larger than 20 W / m * K, specifically, the preform | base_material of low carbon steel or stainless steel.

In the present embodiment, the transfer surface for transferring the shape of the flange surface F2 of the flange portion OLb, that is, the molding surface 66b, is formed by a transfer portion that combines the tip portion of the outer peripheral die 61 and the tip portion of the movable pin 364. It is formed. In other words, the outer peripheral mold 61 and the movable pin 364 constituting the transfer part are formed of materials having different thermal conductivities. In this case, it is possible to adjust the cycle time of the molten resin cooling and molding. For example, by adjusting the area of the front end surface of the movable pin 364 that transfers a part of the flange portion OLb, In addition to adjusting the molding cycle time, optical performance such as astigmatism can be controlled.

[Eighth Embodiment]
Hereinafter, an optical element molding die and an optical element manufacturing method according to the eighth embodiment will be described. The molding die and the manufacturing method according to the eighth embodiment are modifications of the fifth embodiment, and parts that are not particularly described are the same as those of the fifth embodiment.

FIG. 14A is a partially enlarged cross-sectional view of the fixed mold 41 and the movable mold 42 in the present embodiment, and shows a mold closed state and a mold clamped state. FIG. 14B shows a state in which the lens OL is protruded after the fixed mold 41 and the movable mold 42 are opened.

Of the plurality of movable pins 64 and 364 shown in FIG. 14, the base material of some of the movable pins 364 is made of a low thermal conductive material, and the low thermal conductive material constituting such a base material has a thermal conductivity of 0. It has a thermal conductivity of 0.05 W / m · K or more and 20 W / m · K or less. For example, 6-4Ti can be used as a base material. The other movable pins 64 and the outer peripheral mold 61 are made of a high heat conductive material having a thermal conductivity higher than 20 W / m · K, specifically, a base material of low carbon steel or stainless steel.

In the case of the above-described eighth embodiment, the movable pin 364 that is separated from the gate GT extending from the lens OL is formed of a low thermal conductive material, and the side of the lens OL that is close to the gate GT and the side that is away from the gate GT. The degree of slow cooling of the molten resin can be finely adjusted. At this time, the movable pin 364 protruding from the side away from the gate GT is formed of a material having a lower thermal conductivity than the movable pin 64 protruding from the side close to the gate GT, and the molten resin on the side away from the gate GT is formed. It is possible to reduce the easiness of cooling and to perform substantially uniform cooling as the lens OL. Thereby, it is possible to suppress aberration deterioration due to surface shape accuracy error, and it is possible to obtain an optical element suitable for an objective lens for an optical pickup device having an NA of 0.80 or more.

[Ninth Embodiment]
Hereinafter, an optical element mold according to the ninth embodiment and a method for manufacturing the optical element will be described. The molding die and the manufacturing method according to the ninth embodiment are modifications of the fifth embodiment, and parts that are not particularly described are the same as those of the fifth embodiment.

FIG. 15A is a partially enlarged cross-sectional view of the fixed mold 41 and the movable mold 42 in the present embodiment, and shows a mold closed state and a mold clamped state. FIG. 15B shows a state in which the lens OL is protruded after the fixed mold 41 and the movable mold 42 are opened.

The base material of the outer periphery type | mold 361 shown in FIG. 15 is comprised with the low heat conductive material, and the low heat conductive material which comprises such a base material has 0.05 W / m * K or more and 20 W / m * K. For example, 6-4Ti can be used as a base material. The movable pin 64 is made of a high heat conductive material having a thermal conductivity higher than 20 W / m · K, specifically, a base material of low carbon steel or stainless steel.

In the present embodiment, the transfer surface for transferring the shape of the flange surface F2 of the flange portion OLb, that is, the molding surface 66b is formed by a transfer portion that combines the tip portion of the outer peripheral die 361 and the tip portion of the movable pin 64. It is formed. That is, the outer peripheral mold 361 and the movable pin 64 constituting the transfer part are formed of materials having different thermal conductivities. As a result, it is possible to adjust the cycle time of the cooling and molding of the molten resin. For example, by adjusting the area of the tip surface of the movable pin 64 that transfers a part of the flange portion OLb, In addition to adjusting the molding cycle time, optical performance such as astigmatism can be controlled.

Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and various modifications are possible. For example, the shape of the cavity CV provided in the injection mold composed of the fixed mold 41 and the movable mold 42 is not limited to the illustrated one, and various shapes can be used. That is, the shape of the cavity CV formed by the core portions 52, 52 and the like is merely an example, and can be appropriately changed according to the use of the lens OL.

Claims (13)

1. A method of manufacturing an optical element having an optical function part having a concave and convex shape on the optical surface and a flange part,
   A transfer surface for transferring the concavo-convex shape is provided, and a nesting in which a base material is composed of a low thermal conductive material having a thermal conductivity of 20 W / m · K or less is provided in at least one of a fixed mold and a movable mold. A molding step of molding an optical element by injection molding using a pair of molds;
   A mold release step of separating the optical element by separating the fixed mold and the movable mold and projecting a part other than the optical surface of the optical element molded using a projecting member;
   An optical element manufacturing method comprising:
2. A method of manufacturing an optical element having an optical function part having a concave and convex shape on the optical surface and a flange part,
   Heat transfer suppression comprising a transfer surface for transferring irregularities, and comprising a low thermal conductivity material having a thermal conductivity of 20 W / m · K or less between the surface processed layer forming the transfer surface and the substrate A molding step of molding an optical element by injection molding using a pair of molds provided with at least one of a fixed mold and a movable mold with a nesting having a layer;
   A mold release step of separating the optical element by separating the fixed mold and the movable mold and projecting a part other than the optical surface of the optical element molded using a projecting member;
   An optical element manufacturing method comprising:
3. 2. The first aspect of the invention is characterized in that at least a part of the transfer portion for transferring the shape of the flange portion is made of a low thermal conductivity material having a thermal conductivity of 20 W / m · K or less. Or the manufacturing method of the optical element of a 2nd term | claim.
4. At least one part of the said protrusion member is comprised with the low heat conductive material whose heat conductivity is 20 W / m * K or less, The any one of Claim 1 to 3 characterized by the above-mentioned. The manufacturing method of the optical element of description.
5. The projecting member includes a plurality of members that project parts other than the optical surface of the molded optical element,
   Of the plurality of members, the member protruding from the side close to the gate formed when the optical element is molded and the member protruding from the side away from the gate are formed of materials having different thermal conductivities. The method for manufacturing an optical element according to claim 1 or 2, wherein the optical element is manufactured according to claim 1.
6. The optical element manufacturing method according to claim 5, wherein the member protruding from the side away from the gate is formed of a material having a lower thermal conductivity than the member protruding from the side close to the gate. Method.
7. The protruding member is a member that transfers a part of the shape of the flange part and protrudes a part of the flange part,
   Of the transfer part for transferring the shape of the flange part, the transfer part excluding the part transferred by the protrusion member and the protrusion member are formed of materials having different thermal conductivity. A method for manufacturing an optical element according to claim 1 or 2.
8. The said movable metal mold | die is equipped with the said nest | insert which has the said base material or heat conduction suppression layer comprised with the low heat conductive material, The range of any one of Claim 1 to 7 characterized by the above-mentioned. Of manufacturing the optical element.
9. The said fixed metal mold | die is equipped with the said nest | insert which has the said base material or heat conduction suppression layer comprised with the low heat conductive material, The range of any one of Claim 1 to 8 characterized by the above-mentioned. Of manufacturing the optical element.
10. The method of manufacturing an optical element according to any one of claims 1 to 9, wherein the optical element is a lens.
11. An optical element molding die for molding an optical element by a pair of molds,
    At least one of the pair of molds is
    A nesting comprising a transfer surface for transferring the concavo-convex shape, and a base material composed of a low thermal conductive material having a thermal conductivity of 20 W / m · K or less,
    A mold member for supporting the insert;
    A protruding member for releasing the optical element by protruding a portion other than the optical surface of the optical element formed when the pair of molds are separated from each other;
    An optical element molding die comprising:
12. An optical element molding die for molding an optical element by a pair of molds,
    At least one of the pair of molds is
    Heat transfer suppression comprising a transfer surface for transferring irregularities, and comprising a low thermal conductivity material having a thermal conductivity of 20 W / m · K or less between the surface processed layer forming the transfer surface and the substrate Nesting with layers,
    A mold member for supporting the insert;
    A protruding member for releasing the optical element by protruding a portion other than the optical surface of the optical element formed when the pair of molds are separated from each other;
    An optical element molding die comprising:
13. An optical element formed using the optical element molding die according to claim 11 or 12.

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