JP2013075457A - Molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding apparatus that can stably mold optical components with excellent appearance and quality by using a simple composition while shortening a molding cycle.SOLUTION: Since heat conduction from a mold space CV to core molds 52, 42 is controlled with heat insulation layers 52c, 42c, the temperature of a melting resin is held, and the transfer face shapes of the core molds 52, 42 can be precisely transferred. In addition, heat of the melting resin is not released, local eccentricity of the heat is restrained to be generated and unevenness of the temperature can be dissolved by quickly dispersing the heat with high heat conduction base materials 52d, 42d.

Description

  The present invention relates to a molding apparatus suitable for molding an optical component such as a lens.

  Patent Literature 1 is disclosed as a molding method for suppressing the occurrence of sink marks and weld lines and obtaining a molded product having a small birefringence. This disclosed technique relates to selectively heating only the surface processed layer by induction heating. Here, as an example, a cycloolefin resin (Tg = 138 to 140 ° C.) is filled in a state of 140 ° C. or higher by induction heating, cooled to near the heat deformation temperature of the resin (about 120 to 125 ° C.), and then molded. Shown to take out goods. However, this technique has drawbacks. Specifically, it takes time to reach a desired temperature by induction heating, and it takes time to cool the molded product to a temperature at which it can be stably taken out, resulting in poor productivity. Moreover, in order to stabilize the performance of a molded article, it is also necessary to stabilize the temperature control by induction heating. Furthermore, in addition to the normal mold temperature control device, a new temperature control device for induction heating is required, and the mold becomes complicated because the coil for induction heating is built in the die. There is a drawback that the cost for manufacturing the mold is increased, and in addition, a new production facility is required, which increases the manufacturing cost of the molded product.

  Thus, while there is a request for the appearance quality of a molded product, there is a request for shortening the molding cycle. However, in order to shorten the molding cycle, it is generally considered to lower the temperature of the mold. However, if the mold temperature is lowered, cooling of the resin filled in the mold is accelerated, and there is a risk of appearance defects such as flow marks and jetting. Is limited. On the other hand, it is possible to suppress the escape of heat from the resin and to suppress the appearance defect by molding using a heat insulating mold having a heat insulating layer. However, according to the study of the present inventor, when molding is performed by lowering the mold temperature using a heat insulating mold, a large temperature is generated between the mold cavity forming the product outer shape and the transfer surface forming the optical surface. It was found that unevenness occurred and birefringence deteriorated.

JP 2000-127175 A

  The present invention has been made in view of the problems of the prior art, and provides a molding apparatus that can stably mold optical components with excellent appearance quality using a simple configuration while shortening the molding cycle. For the purpose.

The molding apparatus according to claim 1, wherein the molding apparatus includes a mold for molding an optical component.
The mold includes a surface processing layer, a heat insulating layer having a thermal conductivity of 20 W / m · K or less, and a high thermal conductivity mother having a thermal conductivity of 70 W / m · K or more in this order from the transfer surface side for molding an optical component. Have materials,
The temperature of the mold at the time of molding is set lower than the glass transition temperature Tg of the material of the optical component to be molded.

  As a result of diligent research, the present inventor, when merely forming a heat insulating layer having a thermal conductivity of 20 W / m · K or less in a mold, It was found that heat was trapped and a local bias occurred, which caused temperature non-uniformity and birefringence. And based on such knowledge, it derived | led-out that the metal mold | die base material was formed from the raw material of high heat conductivity whose heat conductivity is 70 W / m * K or more. In other words, the heat of the optical component material supplied to the mold at the time of molding is accumulated and the heat is quickly dispersed by the high heat conductive base material provided on the back side of the heat insulation layer before the local bias occurs. He tried to eliminate the non-uniformity. Thereby, the occurrence of sink marks and weld lines in the molded product is suppressed, and a molded product with small molding distortion and small birefringence can be obtained. Further, by providing the heat insulating layer, the temperature of the mold at the time of molding can be made lower than the glass transition temperature Tg, so that heating / cooling with a large amount of heat transfer becomes unnecessary and the molding cycle can be shortened.

  According to the present invention, the cooling time can be shortened without impairing the optical properties such as the appearance quality and birefringence of the optical component as a product, and high productivity is enabled by molding with a short cycle. For example, if the conventional molding cycle can be halved, the number of molds can be cut in half, so the cost can be halved. Furthermore, when molding multiple optical components in a single molding, the number of mold cavities Even if halved, the same number of optical components can be molded in the same time. As the number of mold cavities increases, the molding conditions between the cavities become biased, making it difficult to find molding conditions suitable for all cavities, but it is easy to mold by reducing the number of cavities. Conditions can be obtained, and production maintenance and management man-hours can be reduced. If the thermal conductivity of the high thermal conductivity base material is 100 W / m · K or more, the cooling time can be further shortened without impairing the optical characteristics, which is more preferable.

  The molding apparatus according to claim 2 is characterized in that, in the invention according to claim 1, the temperature of the mold at the time of molding is 20 to 70 ° C. lower than the glass transition temperature Tg. By lowering the glass transition temperature Tg by 20 ° C. or more, the molding cycle can be effectively reduced. By increasing the glass transition temperature Tg by 70 ° C. or less, the appearance quality of the optical component can be secured. . More preferably, it is 30-60 ° C. lower than the glass transition temperature Tg.

  According to a third aspect of the present invention, in the invention according to the first or second aspect, the high thermal conductive base material is formed of a copper alloy or a cemented carbide. Thereby, the metal mold | die base material which has the mechanical physical property as a metal mold | die base material, workability, and high thermal conductivity can be obtained.

  A molding apparatus according to a fourth aspect of the present invention is the invention according to any one of the first to third aspects, wherein the mold is provided in a pair and is relatively movable with respect to each other. It has a core type | mold and the outer periphery type | mold arrange | positioned around the said core type | mold, The said core type | mold has the said surface processing layer, the said heat insulation layer, and the said high heat conductive base material, It is characterized by the above-mentioned. If the core mold has the surface processed layer, the heat insulating layer, and the high thermal conductivity base material, the same effect can be obtained by replacing only the core mold even in an existing molding apparatus. Is no longer necessary.

  A molding apparatus according to a fifth aspect is characterized in that, in the invention according to any one of the first to fourth aspects, the surface roughness of the surface processed layer is Ra 0.1 μm or less. Thereby, a highly accurate mirror surface can be given to the molded optical component. Ra 0.05 μm or less is more preferable.

  A molding apparatus according to a sixth aspect is characterized in that, in the invention according to any one of the first to fifth aspects, a thickness of the surface treatment layer is 0.1 μm to 1 mm. If the thickness of the surface processed layer is 0.1 μm or more, the fine structure for transferring the diffraction structure can be processed, and if the thickness is 1 mm or less, for example, the effect of the heat insulating layer can be maintained. The thickness of the surface treatment layer is more preferably 0.1 μm to 300 μm.

  A molding apparatus according to a seventh aspect is characterized in that, in the invention according to any one of the first to sixth aspects, a thickness of the heat insulating layer is 0.1 mm to 10 mm. If the thickness of the heat insulation layer is 0.1 mm or more, a sufficient heat insulation effect can be exhibited. On the other hand, if the thickness is 10 mm or less, temperature nonuniformity can be suppressed even when molding optical parts, for example. The thickness of the heat insulating layer is preferably 0.1 mm to 1 mm.

  A molding apparatus according to an eighth aspect of the invention is characterized in that, in the invention according to any one of the first to seventh aspects, the apparatus has a temperature adjustment device that adjusts the temperature of the mold by circulating the temperature-adjusted liquid. And Thereby, the temperature of the said metal mold | die at the time of shaping | molding can be maintained at the arbitrary values lower than the glass transition point temperature Tg of the raw material of the optical component which it is going to shape | mold.

  In addition to copper alloy and cemented carbide (WC), aluminum alloy, AlN ceramics, Mg alloy, copper tungsten (CuW), copper molybdenum (CuMo), SiC, Al-SiC, etc. should be used as the high thermal conductivity base material. Can do. Also, a sintered compact of graphite and metal as shown in International Publication WO2009 / 051094 and JP2010-2448064 can be used.

  As the heat insulating layer, besides PI (polyimide) having a thermal conductivity of 20 W / m · k or less, zirconia, a titanium alloy, tempered glass, silicon nitride, or the like can be used. As zirconia, those stabilized with yttrium oxide, aluminum oxide, or magnesium oxide are suitable.

  The surface processed layer may be formed by forming a heat insulating layer on a highly heat conductive mold base material, and then performing Ni machining with Ni alloy plating. At this time, if the heat insulating layer is polyimide, it can be formed by spin coating or bonding a polyimide film. Further, if it is a zirconia layer, it may be formed by thermal spraying, or a zirconia sintered body or the like may be bonded and bonded.

  The mold temperature may be set 30 ° C. to 60 ° C. lower than the glass transition temperature (Tg) of the material and 10 ° C. to 40 ° C. lower than the deflection temperature under load. The effect that the cooling time can be shortened is further obtained.

  As the resin material used for molding, thermoplastic resins such as PC, PMMA, COP, COC, modified PC, and modified polyester can be suitably used.

  Optical elements include transparent optical elements such as medical chips, in addition to lenses and parallel plate elements.

  ADVANTAGE OF THE INVENTION According to this invention, the shaping | molding apparatus which can shape | mold the optical component of the outstanding external appearance quality stably using a simple structure can be provided, shortening a shaping | molding cycle.

It is the schematic of the shaping | molding apparatus 100 concerning this Embodiment. It is sectional drawing of the fixed metal mold | die 50 and the movable metal mold | die 40 in a shaping | molding state. 3 is a flowchart for explaining the operation of the molding apparatus 100. It is sectional drawing of the metal mold | die concerning a modification. It is sectional drawing of the metal mold | die concerning a modification. It is sectional drawing of the metal mold | die concerning a modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a molding apparatus 100 according to the present embodiment. The molding apparatus 100 includes an injection molding machine 10 that is a main body part that performs injection molding to produce a molded product MP, a take-out device 20 that is an accessory part that takes out the molded product MP from the injection molding machine 10, and the molding device 100. And a control device 30 that comprehensively controls the operation of each unit.

  The injection molding machine 10 includes a fixed platen 11, a movable 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 the movable mold 40 and the fixed mold 50 between the movable platen 12 and the fixed platen 11 and clamping both the molds 40 and 50.

  The fixed platen 11 is fixed to the center of the support frame 14 so as to face the movable platen 12, and supports the take-out device 20 on the upper part thereof. The stationary platen 11 detachably supports the stationary mold 50. Note that the fixed platen 11 is fixed to the mold clamping plate 13 via a tie bar so that it can withstand the pressure of mold clamping during molding. The molded product MP includes a plurality of lenses OL as optical components, and the plurality of lenses OL are connected to each other via a sprue or runner that is formed at the time of molding.

  The movable platen 12 is supported by a slide guide 15a so as to be movable back and forth with respect to the fixed platen 11. The movable platen 12 detachably supports the movable mold 40. The movable plate 12 is provided with an ejector 70 on the back surface thereof. The ejector 70 can push the runner portion of the molded product MP in the movable mold 40 to the fixed mold 50 side by the ejector pin 71, and can be transferred by the take-out device 20. In addition, as a method of extruding the molded product from the mold, in addition to the method using the ejector pin 71, a method of extruding the core mold may be used.

  The mold clamping machine 13 is fixed to the end of the support frame 14. The mold clamping machine 13 supports the movable board 12 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 12 and enables a smooth reciprocating movement in the advancing / retreating direction of the movable platen 12 with respect to the fixed platen 11. 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 12 moves toward and away from the fixed platen 11 and moves freely. As a result, the fixed platen 11 and the movable platen 12 move close to and away from each other, and the fixed mold 50 is movable. Mold clamping and mold opening with the mold 40 are performed.

  The injection device 16 includes a cylinder 16a, a raw material reservoir 16b, a screw 16c, and a resin injection end 16d. The injection device 16 operates at an appropriate timing under the control of the control device 30, and can discharge the molten resin from the resin injection end 16d in a temperature-controlled state. The injection device 16 can detachably connect the resin injection end 16d of the cylinder 16a to the fixed platen 11, and the fixed die 50 and the movable die 40 are clamped via the fixed platen 11. The molten resin can be supplied to the flow path portion communicating with the mold space CV (see FIG. 2) formed at a desired timing.

  The temperature adjustment device 17 is a part that adjusts the temperature of the molds 40 and 50 of the injection molding machine 10. The temperature adjustment device 17 has a temperature adjustment circuit, and the temperature of the fixed mold 50 and the movable mold 40 can be adjusted. Specifically, for example, by supplying a temperature adjusting medium (oil, water, etc.) to the fluid circulation paths 51a, 41a (see FIG. 2) provided in the fixed outer peripheral mold 51 and the movable outer peripheral mold 41, the fixed metal The mold 50 and the movable mold 40 are heated to a necessary temperature. The temperature may be adjusted using a heater or the like without using a medium.

  The take-out device 20 includes a hand 21 that can hold the 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. The molded product MP remaining in the movable die 40 after the fixed die 50 and the movable die 40 are separated from each other and opened. It has a role of gripping 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 40 and 50 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 mold space CV formed between the molds 40 and 50 by operating the screw 16c and the like. In addition, the inside of the mold space CV is held at a constant holding pressure value during holding after resin filling. The ejector control unit 33 operates the ejector 70 to push out the molded product MP remaining in the movable mold 40 from the movable mold 40 when the mold is opened. The take-out device controller 34 operates the take-out device 20 to grip the molded product MP remaining in the movable mold 40 after mold opening and mold release and carry it out of the injection molding machine 10.

  FIG. 2 is a cross-sectional view of the fixed mold 50 and the movable mold 40 in the molded state. The fixed mold 50 and the movable mold 40 can be opened and closed with the parting line PL as a boundary.

  A mold space CV that is a space sandwiched between both molds 41 and 42 corresponds to the shape of a lens as an optical component that is a molded product. The lens to be molded is, for example, an objective lens for an optical pickup device, and is a lens that satisfies NA of 0.85 or more with respect to a light beam having a wavelength for BD.

  The fixed mold 50 includes a core mold 52 as a fixed-side insert, an outer peripheral mold 51 having a structure capable of supporting and fixing the fixed-side insert integrally, and the outer peripheral mold 51 and the core mold 52. An attachment plate 53 for fixing to the platen of the molding machine and a mold plate 54 for holding the outer peripheral die 51 are provided. Here, the outer peripheral mold 51 and the mounting plate 53 are mold members that hold and fix the core mold 52 as a nesting from the periphery.

  The outer periphery mold | type 51 has the end surface 51b which forms the parting line PL. A flange molding surface 51 c is provided at the tip of the outer peripheral mold 51. In addition, a core insertion hole 51c, which is a cylindrical through hole for inserting and supporting the core mold 52, is formed inside the outer peripheral mold 51. The outer peripheral mold 51 is made of SUS steel such as STAVAX (registered trademark of Woodeholms).

  The core mold 52 has a cylindrical outer peripheral side surface that can be fitted into the core insertion hole 51c, and an optical surface transfer surface 52a for forming a mold space CV is provided at the tip of the core mold 52. Yes. The optical surface transfer surface 52a is a concave surface and is a transfer surface for molding one optical surface of a lens to be molded.

  The core mold 52 includes a surface processing layer 52b, a heat insulating layer 52c, and a high thermal conductive base material 52d in order from the optical surface transfer surface 52a side.

  The mounting plate 53 includes a sprue SP extending in the axial direction and a runner RN extending in the radial direction. The mounting plate 53 is connected to the external injection device 16 via a gate GT formed between the end faces 51b and 41b. It communicates with the mold space CV.

  The high heat conductive base material 52d is a main part constituting the core type 52 which is a nesting, and is made of a high heat conductive material having a thermal conductivity of 70 W / m · K or more, specifically, a copper alloy.

  The heat insulating layer 52c has a thermal conductivity lower than that of the high heat conductive base material 52d, and is sandwiched between the surface processed layer 52b and the high heat conductive base material 52d to prevent rapid cooling of the lens being molded. Have a role. The shape of the heat insulating layer 52c corresponds to the shape of the mold space CV. Specifically, the heat insulating layer 52c is continuously formed over the entire optical surface transfer surface 52a and a part of the flange surface molding surface 51c, and the thickness thereof is substantially uniform between 0.1 mm and 1 mm. is there. In addition, the heat conductivity of the heat insulation layer 52c is comprised with the low heat conductivity material of 20 W / m * K or less, for example, it can form using resin materials, such as ceramics, such as a zirconia and an alumina, and a polyimide.

  The surface processed layer 52b is a layer for forming the optical surface transfer surface 52a and the flange surface molding surface 51c. The surface of the surface processed layer 52b continuously extends over the optical surface transfer surface 52a and a part of the flange surface molding surface 51c. The surface processed layer 52b has a surface roughness of 0.1 μm or less and a thickness of 0.1 μm to 1 mm. The thin part of the lens to be molded may be thin and the thick part may be thick. The surface processed layer 52b is formed of a nickel phosphorous plating layer as a material with excellent mirror surface workability and low tool wear and good machinability. The nickel phosphorus plating layer is formed using an electroless nickel plating method. By this surface processing of the nickel phosphorus plating layer, an optical surface transfer surface 52a having a precise shape is formed as the surface of the nickel phosphorus plating layer. Furthermore, the optical surface transfer surface 52a can be coated with a thin release film formed of a resin material.

  The surface processed layer 52 b is also provided between the core mold 52 and the outer peripheral mold 51 so as to cover the core mold 52 in order to prevent peeling of the plating.

  The movable mold 40 includes a core mold 42 as a movable side insert, an outer peripheral mold 41 having a structure capable of supporting and fixing the movable side insert integrally, an outer peripheral mold 41 and a core mold 42. A mounting plate 43 for fixing to the platen of the molding machine and a mold plate 44 for holding the outer peripheral mold are provided. Here, the outer peripheral die 41 and the mounting plate 43 are die members that hold and fix the core die 42 as a nesting from the periphery.

  The outer periphery mold | type 41 has the end surface 41b which forms the parting line PL. A flange forming surface 41 d is provided at the tip of the outer peripheral die 41. Further, a core insertion hole 41 c that is a cylindrical through hole for inserting and supporting the core mold 42 is formed inside the outer peripheral mold 41. The outer peripheral die 41 is made of SUS steel such as STAVAX.

  The core mold 42 has a cylindrical outer peripheral side surface that can be fitted into the core insertion hole 41c, and an optical surface transfer surface 42a for forming a mold space CV is provided at the tip of the core mold 42. Yes. The optical surface transfer surface 42a is a concave surface having a different curvature from the optical surface transfer surface 52a, and is a transfer surface for molding the other optical surface of the lens to be molded.

  The core mold 42 includes, in order from the optical surface transfer surface 42a side, a surface processed layer 42b, a heat insulating layer 42c, and a high heat conductive base material 42d.

  The high heat conductive base material 42d is a main part constituting the core type 42 that is nested, and is made of a high heat conductive material having a thermal conductivity of 70 W / m · K or more, specifically, a copper alloy.

  The heat insulating layer 42c has a thermal conductivity lower than that of the high heat conductive base material 42d, and is sandwiched between the surface processed layer 42b and the high heat conductive base material 42d as a heat insulating layer that prevents rapid cooling of the lens being molded. Have a role. The shape of the heat insulating layer 42c corresponds to the shape of the mold space CV. Specifically, the heat insulation layer 42c is continuously formed over the entire optical surface transfer surface 42a and a part of the flange surface molding surface 41c, and the thickness thereof is substantially uniform between 0.1 mm and 1 mm. is there. The heat conductivity of the heat insulating layer 42c is made of a low heat conductivity material of 20 W / m · K or less, and can be formed using a ceramic material such as zirconia or alumina, or a resin material such as polyimide, for example.

  The surface processed layer 42b is a layer for forming the optical surface transfer surface 42a and the flange surface molding surface 41c. The surface of the surface processing layer 42b extends continuously over the optical surface transfer surface 42a and a part of the flange surface molding surface 41c. The surface processed layer 42b has a surface roughness Ra of 0.1 μm or less and a thickness of 0.1 μm to 1 mm. The thin part of the lens to be molded may be thin and the thick part may be thick. The surface processed layer 42b is formed of a nickel phosphorus plating layer as a material having excellent mirror surface workability and low tool wear and good machinability. The nickel phosphorus plating layer is formed using an electroless nickel plating method. By this surface processing of the nickel phosphorus plating layer, an optical surface transfer surface 42a having a precise shape is formed as the surface of the nickel phosphorus plating layer. Furthermore, the optical surface transfer surface 42a can be coated with a thin release film formed of a resin material.

  The surface processed layer 42b is also provided between the core mold 42 and the outer peripheral mold 41 so as to cover the core mold 42 in order to prevent peeling of the plating.

  FIG. 3 is a flowchart for explaining the operation of the molding apparatus 100. First, as shown in FIG. 3, the temperature adjusting device 17 of the molding apparatus 100 is operated to heat both molds 40 and 50 to a temperature suitable for molding (a temperature 20 to 70 ° C. lower than the glass transition temperature of the material). (Step S10). When it is desired to shorten the molding cycle on a smooth surface, it is desirable to make it lower than the heat distortion temperature. In particular, when fine shape transferability corresponding to a diffractive structure or the like is required, the temperature is preferably close to the glass transition temperature Tg.

  Next, the opening / closing drive device 15 is operated to advance the movable platen 12 to start mold closing (step S11). By continuing the closing operation of the opening / closing driving device 15, the movable platen 12 moves to the fixed platen 11 side to the die contact position where the fixed die 50 and the movable die 40 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 50 and the movable mold 40 with a necessary pressure (step S12).

  After the mold clamping, the injection device 16 is operated in the injection molding machine 10 to apply the heated molten resin to the mold space CV between the clamped fixed mold 50 and the movable mold 40 at a necessary pressure. Injection is performed (step S13). Thus, a filling process is performed in which the resin is filled into the mold space CV between the fixed mold 50 and the movable mold 40 via the clamped sprue SP, the runner RN, and the gate GT. After the filling process, the injection molding machine 10 keeps the resin pressure in the mold space CV at a necessary level (step S14).

  In the molding die 40, the mold space CV and the die are appropriately heated by the temperature adjusting device 17, and the molten resin supplied from the injection device 16 is gradually cooled, and the molten resin is solidified with the cooling. Then, it waits for the completion of molding (step S15). At this time, heat conduction from the mold space CV to the core molds 52 and 42 is suppressed by the heat insulating layers 52c and 42c, so that the temperature of the molten resin can be maintained and the transfer surface shape of the core molds 52 and 42 can be accurately transferred. . Further, by quickly dispersing the heat by the high heat conductive base materials 52d and 42d, it is possible to suppress the occurrence of local bias due to the heat of the molten resin being accumulated, and the temperature non-uniformity can be eliminated. Thereby, the occurrence of sink marks and weld lines in the molded product is suppressed, and a molded product with small molding distortion and small birefringence can be obtained. Further, by providing the heat insulating layer, the temperature of the mold during molding can be made lower than the glass transition temperature Tg, so that heating / cooling with a large amount of heat transfer becomes unnecessary and the molding cycle can be shortened.

  After completion of molding, the mold clamping is finished, and the opening / closing drive device 15 is operated to perform mold opening for retracting the movable platen 12 (step S16). Along with this, the movable mold 40 moves backward, and the fixed mold 50 and the movable mold 40 are separated. As a result, the molded product, that is, the lens is released from the fixed mold 50 while being held by the movable mold 40. Next, in the injection molding machine 10, the ejector 70 is operated to eject the molded product (step S17). Specifically, the sprue portion or the like of the molded product is released from the movable mold 40 by the protrusion by the ejector pin 71. After the molded product is released from the movable mold 40, the take-out device 20 is operated, and an appropriate position of the projected molded product is gripped by the hand 21 and carried out to the outside (step S18).

(Examples) Table 1 shows the results of an evaluation conducted by comparing the examples performed by the present inventors with comparative examples.
The evaluation items in Table 1 are the cooling time shortening effect, appearance, and birefringence. As for the effect of shortening the cooling time, the temperature of the molded product under each condition (here, a parallel plate) immediately after taking out from the mold when the cooling condition after molding is shortened is measured by thermography. Asked. That is, in each mold configuration / mold temperature condition, the cooling time required for the temperature of the molded product to fall below the deflection temperature under load was determined. The appearance is compared with the occurrence of flow mark / jetting near the gate. These poor appearances can be reduced or eliminated by once slowing the injection speed when passing through the gate portion under the general mold configuration / mold temperature conditions as in Comparative Example 1. The birefringence is evaluated by observation with crossed Nicols, and the result of relative comparison with Comparative Example 1 is shown. A polycarbonate resin having a glass transition temperature Tg of 145 ° C. is used as a material to be molded. The molding conditions are a resin temperature of 290 ° C. and a pressure holding condition of 80 to 90 MPa.

[specification]
Comparative Example 1 (Prior Art): The mold surface layer is nickel-plated (thickness 0.05 mm, thermal conductivity 8.4 W / m · K), and the base material is STAVAX (thickness 10 mm, thermal conductivity = 23 W / m · K), and the mold temperature was 120 ° C.
Comparative Example 2: The mold surface layer is nickel-plated (thickness 0.05 mm), and the base material is a copper alloy (HIT MAX manufactured by Hitachi, Ltd., thermal conductivity = 198.7 W / m · K, thickness 10 mm). The mold temperature was 120 ° C.
Comparative Example 3: The surface layer of the mold was nickel-plated (thickness 0.05 mm), the base material was STAVAX (thickness 10 mm, thermal conductivity = 23 W / m · K), and the mold temperature was 110 ° C. .
Comparative Example 4: The surface layer of the mold is nickel-plated (thickness 0.05 mm), the base material is ZrO ₂ (thickness 10 mm, thermal conductivity = 3 W / m · K), and the mold temperature is 100 ° C. did.
Comparative Example 5: The mold surface layer is nickel-plated (thickness 0.05 mm), the heat insulation layer is polyimide (thickness 0.04 mm, thermal conductivity = 0.3 W / m · K), and the base material is STAVAX (thickness) 10 mm, thermal conductivity = 23 W / m · K), and the mold temperature was 100 ° C.
Example: Nickel plating (thickness 0.05 mm) for the surface layer of the mold, polyimide (thickness 0.04 mm, thermal conductivity = 0.3 W / m · K) for the heat insulation layer, and copper alloy (Hitachi) HIT MAX manufactured by Seisakusho, thermal conductivity = 198.7 W / m · K, thickness 10 mm), and mold temperature was 100 ° C.

[Discussion]
Evaluation was performed based on Comparative Example 1 (cooling time of 100 seconds) corresponding to the prior art. In Comparative Example 2 in which the base material was changed to a copper alloy having high thermal conductivity, the cooling time was shortened by 20 seconds. However, it was found that the appearance quality deteriorates. Further, in Comparative Example 3 in which the mold temperature is lowered by 10 ° C. compared to Comparative Example 1, the cooling time is shortened by 50 seconds, but the appearance quality is deteriorated, and the birefringence is also deteriorated as compared with Comparative Example 1. I understood that. Further, in the case of Comparative Example 4 in which the base material is changed to ZrO ₂ and the mold temperature is lowered by 20 ° C. compared to Comparative Example 1, the cooling time is shortened by 10 seconds and the appearance quality is maintained. It was found that refraction was worse than that of Comparative Example 1. In contrast to Comparative Example 1, a heat insulating layer is provided between the surface layer and the base material, and in Comparative Example 5 in which the mold temperature is lowered by 20 ° C., the cooling time is shortened by 50 seconds and the appearance quality is maintained. However, the birefringence was found to be worse than that of Comparative Example 1. On the other hand, with respect to Comparative Example 1, the base material was changed to a copper alloy having high thermal conductivity, a heat insulating layer was provided between the surface layer and the base material, and the mold temperature was lowered by 20 ° C. In the case of the example, the cooling time was shortened by 70 seconds, the appearance quality was maintained, and the birefringence was found to be as good as that of Comparative Example 1. Thereby, the effect of the present invention was confirmed.

  In the above-described embodiment, the transfer surface of the mold is shown as an aspherical shape, but the same effect can be obtained by using a flat surface, a spherical surface, or a free-form surface as shown in FIG. Further, a fine shape such as blaze or diffraction may be formed on the surface layer.

  Further, the surface processed layer may be formed by electroforming. As shown in FIG. 5, as a stamper obtained by forming a Ni alloy plating to a desired thickness by electroforming on a master processed in substantially the same shape as the product shape, uniformly processing the laminated surface, and demolding May be used. In this case, the stamper obtained above is directly attached to the core of “high heat conductive base material + heat insulating layer” previously formed and incorporated in the mold with a bolt or indirectly through a fixing member FX having a claw portion. It is possible to mold by fixing to the surface or contacting by vacuum suction or the like.

  Further, as shown in FIG. 6, the surface processed layer may be formed by an electroforming method, and a heat insulating layer may be attached to the back surface thereof. A Ni alloy plating is laminated by electroforming on the master processed in the same shape as the product shape, and after forming a heat insulation layer (and high heat conduction layer) from it, the master is removed from the mold, The given stamper can be obtained. After the formation of each layer, a process for making the surface uniform may be included. In that case, the obtained stamper with a heat insulating layer is fixed directly to the core of the “high heat conduction base material” that has been previously formed and incorporated into the mold with bolts or indirectly via a fixing member FX having a claw portion. Alternatively, it can be formed by contact by vacuum suction or the like.

  The present invention is not limited to the embodiments described in the specification, and other embodiments and modifications are apparent to those skilled in the art from the embodiments and ideas described in the present specification. It is. The description and examples are for illustrative purposes only, and the scope of the invention is indicated by the following claims.

DESCRIPTION OF SYMBOLS 10 Injection molding machine 11 Fixed platen 12 Movable platen 13 Clamping plate 14 Support frame 15 Opening / closing drive device 15a Slide guide 15d Power transmission part 15e Actuator 16 Injection device 16a Cylinder 16b Raw material storage part 16c Screw 16d Resin injection end 17 Temperature control device 20 Extraction device 21 Hand 22 Three-dimensional drive device 30 Control device 31 Opening / closing control unit 32 Injection device control unit 33 Ejector control unit 34 Device control unit 40 Movable mold 41 Outer peripheral mold 41b End surface 41c Core insertion hole 41d Flange molding surface 42 Core mold 42a Optical surface transfer surface 42b Surface processed layer 42c Thermal insulation layer 42d High heat conduction base material 43 Mounting plate 44 Mold plate 50 Fixed mold 51 Peripheral mold 51a Fluid circulation path 51b End surface 51c Core insertion hole 51d Flange molding surface 52 Core mold 52a Optical surface Transfer surface 52b Surface processed layer 52c Thermal insulation layer 52d High thermal conductive base material 53 Mounting plate 54 Mold plate 70 Ejector 71 Ejector pin CV type space FX Fixing member GT Gate PL Parting line SP Sprue

Claims (8)

In a molding apparatus equipped with a mold for molding optical components,
The mold includes a surface processing layer, a heat insulating layer having a thermal conductivity of 20 W / m · K or less, and a high thermal conductivity mother having a thermal conductivity of 70 W / m · K or more in this order from the transfer surface side for molding an optical component. Have materials,
A molding apparatus characterized in that a temperature of the mold at the time of molding is set lower than a glass transition temperature Tg of a material of an optical component to be molded.   The molding apparatus according to claim 1, wherein a temperature of the mold during molding is 20 to 70 ° C. lower than the glass transition temperature Tg.   The molding apparatus according to claim 1, wherein the high thermal conductive base material is formed of a copper alloy or a cemented carbide.   A pair of the molds are provided and are movable relative to each other. The mold includes a core mold and an outer peripheral mold disposed around the core mold. The molding apparatus according to claim 1, further comprising: the surface processed layer, the heat insulating layer, and the high thermal conductive base material.   The surface roughness of the said surface treatment layer is Ra0.1micrometer or less, The shaping | molding apparatus in any one of Claims 1-4 characterized by the above-mentioned.   The molding apparatus according to claim 1, wherein a thickness of the surface processed layer is 0.1 μm to 1 mm.   The thickness of the said heat insulation layer is 0.1 mm-10 mm, The shaping | molding apparatus in any one of Claims 1-6 characterized by the above-mentioned.   The molding apparatus according to claim 1, further comprising a temperature adjustment device that adjusts the temperature of the mold by circulating a temperature-adjusted liquid.