JP5846994B2 - Method for manufacturing optical lens mold and method for manufacturing plastic lens - Google Patents

Description

  The present invention relates to a method for manufacturing an optical lens mold and a method for manufacturing a plastic lens.

  Conventionally, an injection compression molding method using a thermoplastic resin such as a polycarbonate resin or a methacrylic resin is known as a method for molding a plastic lens for eyeglasses. For example, Patent Document 1 discloses such an injection compression molding method. An example of the law is disclosed. According to the injection compression molding method, by further compressing the resin injected and filled in the mold cavity, the shrinkage of the molten resin can be corrected, and uniform and high shape accuracy can be obtained. Even a plastic lens having a complicated optical surface shape such as a lens can be molded with high accuracy.

An injection mold used in the injection compression molding method of Patent Document 1 is an insert mold as an optical lens molding mold for molding an optical surface of a lens, which can be exchanged according to the type of lens to be molded. The mold is housed in insert guide members provided in each of the movable mold and the fixed mold, thereby forming a lens molding cavity.
Insert molds as optical lens molds are usually formed using steel materials such as maraging steel and beryllium copper alloy, but for reasons such as being able to mold a smoother and more accurate optical surface. When molding a plastic lens, it may be more convenient to use a glass mold. For this reason, there is known an optical lens molding die in which a glass base material on which a molding surface for molding an optical surface of a lens is formed is bonded to a metal base (see Patent Document 2).

JP-A-9-272143 JP 2011-186052 A

  By the way, in the injection mold as described in Patent Document 1, a slight gap is provided between the insert mold and the insert guide member to facilitate the insertion of the insert mold. Such a gap is also necessary for smooth operation when the insert mold slides in the insert guide member. For this reason, the insert mold may be inclined with respect to the axial direction depending on the size of the gap provided between the insert guide member and the insert guide member. And when the inclination becomes large, when an optical lens molding die formed by joining a glass substrate to a metal pedestal is used as an insert mold, the corner of one end of the glass substrate is the insert guide member. In some cases, the inner peripheral surface may come into contact with the inner peripheral surface, and at this time, there is a concern that a crack that causes the glass base material to break may occur.

  When joining the glass base and the metal base, it is conceivable to use a jig to prevent the glass base from protruding from the outer periphery of the metal base. As long as the outer peripheral surface of the metal pedestal is flush with the outer peripheral surface of the metal pedestal, contact between the glass substrate and the inner peripheral surface of the insert guide member is inevitable. As a result, the optical lens molding die of Patent Document 2 can be applied without problems to the insert mold on the fixed mold side that does not slide, but the movable mold side that repeatedly slides inside the insert guide member for each molding shot. This insert mold has a problem that it is difficult to apply because of a high risk of breakage of the glass substrate.

  The present invention has been made in view of the circumstances as described above, and an optical lens molding die obtained by joining a glass base on which a molding surface for molding an optical surface of a lens is formed to a metal base. It is an object of the present invention to provide a method for manufacturing an optical lens mold that can effectively avoid breakage of a glass substrate in the state of use.

  An optical glass molding die manufacturing method according to the present invention is an optical lens molding die obtained by bonding a glass base material on which a molding surface for molding a plastic lens having a predetermined lens shape is formed to a metal base. In the manufacturing method, the glass substrate is formed to have a smaller diameter than the pedestal, and an assembly jig is closely attached to the outer peripheral surface of the pedestal, and between the assembly jig and the glass substrate. The glass substrate is superposed and bonded to the pedestal in a state where a filler formed to have a thickness matching the diameter difference between the glass substrate and the pedestal is sandwiched.

  According to the present invention, when a plastic lens is molded using an optical lens molding die in which a glass substrate on which a molding surface for molding an optical surface of a lens is formed is bonded to a metal pedestal, Damage to the material can be effectively avoided.

It is explanatory drawing which shows an example of an injection molding apparatus. It is sectional drawing which shows the outline of the shaping | molding die with which the injection molding apparatus shown in FIG. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is a principal part expanded sectional view which expands and shows the circumference | surroundings of the cavity in FIG. It is explanatory drawing for demonstrating an example of the manufacturing method of the optical lens shaping | molding die which concerns on embodiment of this invention. It is CC sectional drawing of FIG. It is a flowchart which shows each step in embodiment of the manufacturing method of the plastic lens which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Injection molding equipment]
FIG. 1 is an explanatory view showing an example of an injection molding apparatus that molds a plastic lens using an optical lens molding die manufactured by applying the method for manufacturing an optical lens molding die according to the present embodiment.

  The injection molding apparatus shown in FIG. 1 includes a mold 50 having a movable mold 1 and a fixed mold 2 as a pair of split molds divided by a parting line PL, and opening / closing and mold clamping of the mold 50 by a toggle link mechanism 65. A mold clamping device 60, and an injection device 80 that melts, kneads, and measures the raw material resin introduced from the hopper 81 and injects it from the nozzle 85.

[Injection device]
An injection apparatus 80 provided in the injection molding apparatus shown in FIG. 1 has a heating cylinder 82 having a nozzle 85 formed at the tip. Inside the heating cylinder 82, a screw whose rotation and forward / backward movement are controlled by the drive unit 84 is disposed.

  Further, a hopper 81 for feeding pellet-shaped raw material resin into the heating cylinder 82 is connected to the proximal end side of the heating cylinder 82. The raw material resin charged into the heating cylinder 82 from the hopper 81 is melted and kneaded by shearing heat and heating from the heater provided in the heating cylinder 82 while being sheared and pulverized by a screw rotating in the heating cylinder 82. Is sent to a cylinder front chamber formed between the front end of the nozzle and the nozzle 85 and weighed. Thereafter, a predetermined amount of raw material resin that is adjusted to a viscosity suitable for injection molding and in a molten state is injected from the nozzle 85. .

[Clamping device]
In the injection pressure molding apparatus shown in FIG. 1, the mold clamping device 60 has a plurality of tie bars 63 installed between a fixed die plate 61 and a rear plate 62 erected on a gantry 66 at a predetermined interval, and a movable die plate. 64 is configured to be moved by being guided by the tie bar 63. A molding die 50 is attached between the fixed die plate 61 and the movable die plate 64, and a toggle link mechanism 65 is attached between the rear plate 62 and the movable die plate 64.
As a result, when the toggle link mechanism 65 is driven, the movable die plate 64 is guided by the tie bar 63 to advance and retreat, and accordingly, the mold 50 is opened and closed and the mold is clamped.

  Here, the toggle link mechanism 65 is configured so that the screwed crosshead 73 moves along the ball screw 72 as the ball screw 72 connected to a motor (not shown) rotates. When the cross head 73 moves to the movable die plate 64 side, the toggle links 71A and 71B extend linearly by the connecting links 74A and 74B, and the movable die plate 64 moves so as to approach the fixed die plate 61 (advance). To do. On the contrary, when the cross head 73 moves to the rear plate 62 side, the toggle links 71A and 71B are bent inward by the connecting links 74A and 74B so that the movable die plate 64 is separated from the fixed die plate 61. Move (retreat).

[Molding mold]
FIG. 2 is a cross-sectional view showing a cross section of the molding die 50 shown in FIG. 1 cut along a plane perpendicular to the paper surface passing through the central axis, and shows an initial state in which the die is closed. 3 is a cross-sectional view taken along the line AA in FIG. 2, FIG. 4 is a cross-sectional view taken along the line BB in FIG. 2, and FIG. 5 is an enlarged cross-sectional view of the main part showing the periphery of the cavity 3 in FIG. FIG.

  In the examples shown in these drawings, a pair of split molds, a mold 50 and a movable mold 1 and a fixed mold 2 are sandwiched between two movable cavities 3 for molding a plastic lens of a predetermined shape and a gate G. Thus, a runner 49 as a resin flow path connected to each cavity 3 is formed. A sprue bush 47 that forms a sprue 48 connected to the runner 49 at a right angle is attached to the template 10 of the fixed mold 2.

The mold body 4 of the movable mold 1 has two insert guide members 5 and mold plates 6 and 7 for holding them. Inside the insert guide member 5, an insert die 11 as an optical lens molding die is accommodated so as to be slidable in a direction perpendicular to the parting line PL.
The mold body 8 of the fixed mold 2 includes two insert guide members 9 and a template 10, and the insert guide member 9 is held by the template 10 and the mold attachment member 15. Inside the insert guide member 9, an insert mold 12 as an optical lens molding die is accommodated so as to be slidable in a direction perpendicular to the parting line PL.

  A molding die 50 having such a movable die 1 and a fixed die 2 includes an insert die 11 on the movable die 1 side and an insert die 12 on the fixed die 2 side between the movable die 1 and the fixed die 2. A cavity 3 including a molding surface formed in each is formed. The cavity 3 is formed corresponding to the shape of the plastic lens to be molded, and the molding surfaces of the insert molds 11 and 12 forming the cavity 3 are formed on the glass bases 11a and 12a.

  More specifically, in the insert mold 11 on the movable mold 1 side, the molding surface corresponding to one optical surface (the concave surface in the illustrated example) of the plastic lens to be molded has a glass base material 11a. It is formed by joining the said glass base material 11a to the metal base 11b. Similarly, in the insert mold 12 on the fixed mold 2 side, a molding surface corresponding to the other optical surface of the plastic lens to be molded (in the example shown, the surface on the convex surface side) is formed on the glass substrate 12a. The glass substrate 12a is formed by bonding to a metal base 12b (see FIG. 5).

In the present embodiment, the insert molds 11 and 12 as such optical lens molds are manufactured in the following procedure.
Since the insert mold 11 on the movable mold 1 side and the insert mold 12 on the fixed mold 2 side can be manufactured in the same procedure, in the following example, the insert mold 11 on the movable mold 1 side is used. The case of manufacturing will be described.
FIG. 6 is an explanatory diagram for explaining an example of a method for manufacturing an optical lens molding die according to the present embodiment, and FIG. 7 is a cross-sectional view taken along the line CC in FIG.

As shown in these drawings, in the method of manufacturing an optical lens molding die according to the present embodiment, first, when the glass substrate 11a is joined to the base 11b, the outer periphery of the base 11b is used for positioning. The assembly jig 100 is placed in close contact with the surface.
In the illustrated example, three assembling jigs 100 are installed at equal intervals along the outer peripheral surface of the base 11b. It is preferable to install three or more assembly members 100 so that the positional deviation between the glass substrate 11a and the pedestal 11b is less likely to occur, but the assembly member 100 may be an annular member that surrounds the entire circumference of the pedestal 11b. .
Moreover, it is preferable that each assembly jig 110 is processed with high accuracy so as to be in close contact with the outer peripheral surface of the pedestal 11b without causing a gap between the assembly jigs 110b.

  Next, an adhesive is applied to one or both of the bonding surfaces of the glass substrate 11a and the base 11b, and the bonding surfaces of both are overlapped. At this time, the radius of the glass substrate 11a is made slightly smaller than the radius of the pedestal 11b, and coincides with the diameter difference (difference between the radius of the glass substrate 11a and the radius of the pedestal 11b) d. A metal tape 101 as a filler formed in a thickness is sandwiched between the glass substrate 11 a and the assembly jig 100. And in that state, the glass substrate 11a is overlapped and joined to the base 11b.

  The filler is preferably formed using a metal material so that the thickness does not change due to the pressing force when sandwiched between the glass substrate 11a and the assembly jig 100, such as stainless steel. It is preferable to use a metal tape 101 made of Further, when the metal tape 101 is sandwiched between the glass substrate 11 a and the assembly jig 100, the metal tape 101 is preferably attached to one of the glass substrate 11 a and the assembly jig 100.

  Thereafter, by removing the assembling jig 100 and the metal tape 101, the insert mold 11 in which the glass substrate 11a and the pedestal 11b are joined through the adhesive layer 11c is completed. In the insert mold 11, the outer peripheral surface of the glass substrate 11 a is positioned inside the outer peripheral surface of the base 11 b at a constant interval d along the circumferential direction.

  Thereby, even when the insert molds 11 and 12 are inclined with respect to the axial direction when the insert molds 11 and 12 slide inside the insert guide members 5 and 9, the glass substrates 11a and 12a It is possible to effectively avoid that the outer peripheral surface comes into contact with the inner peripheral surfaces of the insert guide members 5 and 9.

  The diameter difference d between the radius of the glass base materials 11a and 12a and the radius of the bases 11b and 12b can be set to, for example, 5 to 50 μm, preferably 15 to 25 μm. If the above range is not satisfied, the outer peripheral surfaces of the glass base materials 11a and 12a and the outer peripheral surfaces of the bases 11b and 12b are almost flush with each other, and the glass base materials 11a and 12a and the insert guide members 5 and 9 It becomes difficult to avoid contact with the peripheral surface. On the other hand, when the above range is exceeded, the molten resin filled in the cavity 3 enters between the inner peripheral surfaces of the glass base materials 11a and 12a and the inner peripheral surfaces of the insert guide members 5 and 9, and is molded. It is not preferable because burrs are easily generated in the plastic lens.

  Examples of the glass base materials 11a and 12a that form the molding surfaces of the insert molds 11 and 12 manufactured in this way include, for example, a crown system, a flint system, a barium system, a phosphate system, a fluorine-containing system, An amorphous glass material such as a fluorophosphate can be used. Among these, an amorphous glass material having a thermal conductivity of 0.4 to 1.3 W / m · K is appropriately selected and used. Due to its heat insulation effect, the mold temperature is set low and cooling is performed. This is preferable for shortening the time.

Further, such an amorphous glass material is easily suitable for forming a molding surface that requires high precision because the surface can be easily mirror-finished by cutting or polishing.
That is, in order to form a molding surface directly on an insert mold made of steel through a polishing process, a high-level technique and a laborious process are required, but a molding surface for molding an optical surface of a lens was formed. By forming the insert molds 11 and 12 by joining the glass base materials 11a and 12a to the bases 11b and 12b, the formation of the molding surface can be facilitated and the number of manufacturing steps can be reduced. This makes it possible to manufacture the insert dies 11 and 12 at a low cost.

  The glass base materials 11a and 12a are preferably formed with a thickness of 3 to 4 mm so as to sufficiently withstand the injection pressure and holding pressure at the time of injection molding in consideration of molding conditions. Surface treatment can be performed with tempered glass or DLC (diamond-like carbon) for the purpose of preventing damage during handling as well as time.

  Moreover, in order to join such glass base materials 11a and 12a to the bases 11b and 12b, a thermosetting resin having a low linear expansion coefficient and excellent stability in a high temperature environment can be used as an adhesive. And what is necessary is just to join both by apply | coating with a brush etc. to the joint surface of the bases 11b and 12b. As such a thermosetting resin, a sulfur-containing thermosetting resin obtained by reacting a thermosetting monomer containing sulfur is preferable. The sulfur-containing thermosetting resin has a low coefficient of linear expansion, is excellent in stability even in a high temperature environment, and is excellent in adhesiveness (adhesion) with a glass substrate. Furthermore, since the surface tension is low and it is possible to make it adhere to the surface to be adhered in a liquid film state in the state of the monomer before curing, the adhesion formed between the glass base materials 11a and 12a and the bases 11b and 12b. The layer can be a very thin layer.

  The sulfur-containing thermosetting resin is preferably at least one resin selected from thiourethane resins and epithio resins. Here, the thiourethane resin refers to a resin obtained by reacting a polyisocyanate compound and a polythiol compound, and the epithio resin is obtained by reacting a lens raw material monomer having a compound having an epithio group as an essential component. Refers to the resin that is produced. It is particularly preferable to use a thiourethane resin as the sulfur-containing thermosetting resin because it is extremely excellent in adhesion to a glass substrate and is economical. Examples of commercially available thiourethane resins include MR series manufactured by Mitsui Chemicals, Inc., trade names “MR-6”, “MR-7”, “MR-8”, “MR-10”, and “MR-20”. “MR-1746” or the like is preferably used.

  Moreover, although the bases 11b and 12b can be formed using steel materials, such as maraging steel and a beryllium copper alloy, it is preferable to use steel materials with a higher thermal diffusivity than the glass material used for the glass base materials 11a and 12b. preferable.

  In the mold 50 configured as described above, the mold body 4 of the movable mold 1 is fixed to the movable die plate 64 via the mold mounting member 16, and the mold body 8 of the fixed mold 2 is mounted to the mold. It is fixed to the fixed die plate 61 via the member 15. As a result, the mold 50 is attached between the fixed die plate 61 and the movable die plate 64 of the mold clamping device 60.

  Further, the mold mounting member 16 on the movable mold 1 side is provided with a hydraulic cylinder 19 corresponding to each of the insert molds 11, and the piston rod 21 connected to the piston 20 is connected to one end side of the hydraulic cylinder 19. It penetrates through the back insert 22 fixed to. A T-shaped clamp member 23 provided at the tip of each piston rod 21 is formed in a T-shaped groove 24 formed on the back surface of the insert mold 11 (the surface opposite to the surface on which the molding surface is formed). Engageable and detachable.

  Thus, with the mold 50 opened, the piston rods 21 of the respective hydraulic cylinders 19 are advanced, and the T-shaped clamp members 23 provided at the tips of the piston rods 21 are protruded from the insert guide members 5. Thus, the insert mold 11 can be exchanged according to the plastic lens to be molded. When the piston rod 21 of each hydraulic cylinder 19 is retracted, the insert mold 11 attached to the T-shaped clamp member 23 is housed inside the insert guide member 5.

  Similarly, a hydraulic cylinder 26 is provided in the mold mounting member 15 on the fixed mold 2 side so as to correspond to each of the insert molds 12, and a piston rod 28 connected to the piston 27 is provided in the mold mounting member 15. It penetrates. A T-shaped clamp member 29 provided at the tip of each piston rod 28 is formed in a T-shaped groove 30 formed on the back surface of the insert mold 12 (the surface opposite to the surface on which the molding surface is formed). Engageable and detachable.

  Thus, with the mold 50 opened, the piston rod 28 of each hydraulic cylinder 26 is advanced, and the T-shaped clamp member 29 provided at the tip of each piston rod 28 is projected from the insert guide member 9. Thus, the insert mold 12 can be exchanged according to the plastic lens to be molded. When the piston rod 28 of each hydraulic cylinder 26 is retracted, the insert mold 12 attached to the T-shaped clamp member 29 is housed inside the insert guide member 9.

  When the mold body 4 of the movable mold 1 is fixed to the movable die plate 64, the mold body 4 is bolted to the mold mounting member 16 composed of the first member 16A and the second member 16B, as shown in FIG. 17 is attached. At this time, a plurality of disc springs 17 </ b> A inserted on the outer periphery of the bolt 17 are interposed between the mold body 4 of the movable mold 1 and the mold mounting member 16, and the mold body 4 and the mold of the movable mold 1 are interposed. A gap S is formed between the mounting member 16 and the mounting member 16.

The gap S is generated when the movable die plate 64 further advances after the molding die 50 is closed, and the die mounting member 16 guided by the guide pins 18 is pressed against the elastic force of the disc spring 17A. It is designed to be closed. Accordingly, in the illustrated example, each hydraulic cylinder 19 provided on the mold mounting member 16 presses the insert mold 11 via the back insert 22. Thereby, the volume of the cavity 3 at the time of mold clamping is made variable, and the molten resin injected and filled in the cavity 3 can be pressurized and compressed by the insert mold 11.
The guide pin 18 protrudes toward the fixed mold 2 so as to guide the opening / closing operation of the mold 50 and is inserted through an insertion hole formed in the fixed mold 2.

A pressure receiving member 32 is attached to the other end side of the hydraulic cylinder 19 provided on the die attaching member 16 on the movable die 1 side. When the eject rod 34 inserted from the hole 33 formed in the mold attachment member 16 presses the pressure receiving member 32, the hydraulic cylinder 19, the back insert 22 and the insert mold 11 are also pressed and molded in the cavity 3. The lens is pushed out.
At the same time, an eject pin 35 is disposed at the center of the mold attachment member 16 so as to be movable back and forth in parallel with the opening / closing direction of the mold 50. When the pressure receiving member 36 attached to the eject pin 35 is pressed by the eject rod 38 inserted from the hole 37 formed in the mold attaching member 16, the eject pin 35 is pushed out.
Therefore, when the mold is opened, the ejected rods 34 and 38 are advanced to take out the molded product.

  As shown in FIG. 4, the spring force of the spring 42 wound around the outer periphery of the eject return pin 41 acts on the pressure receiving member 36 in the left direction in the figure. Although not particularly shown, the pressure receiving member 32 has the same structure so that a leftward spring force acts in the drawing. Thus, when the eject rods 34 and 38 are retracted, the pressure receiving members 32 and 36 are also retracted and returned to the standby position.

  Moreover, the shaping | molding die 50 has the nozzle shut mechanism 90 which obstruct | occludes the nozzle 85 of the injection apparatus 80, as shown in FIG. The nozzle shut mechanism 90 has a nozzle shut pin 91 as a blocking member protruding into the sprue 48 formed by the sprue bush 47. The nozzle shut pin 91 is connected to a piston rod 94 of a hydraulic cylinder 93 via a connecting piece 92, and the hydraulic cylinder 93 is fixed to the mold mounting member 15 by a cylinder mounting plate 95. As a result, when the hydraulic cylinder 93 is driven in a state where the nozzle 85 is in pressure contact with the sprue bush 47, the nozzle shut pin 91 projects into the sprue 48 and closes the nozzle 85, thereby preventing back flow of the resin. Yes.

[Plastic lens manufacturing method]
In order to manufacture a plastic lens using the injection molding apparatus as described above, for example, the steps (ST1 to ST10) shown in the flowchart of FIG. 8 can be sequentially performed.

  In ST1, a resin pressurizing condition is set. This is for adjusting the clamping force according to the characteristics of the plastic lens to be molded (lens shape, lens power, etc.) in advance in order to apply an appropriate pressure to the resin in the cavity 3 in advance. is there.

In ST2, weighing is performed. In the injection device 80, the pellet-shaped raw resin charged from the hopper 81 is melted and kneaded by shearing heat and heating from the heater provided in the heating cylinder 82 while being sheared and pulverized by a screw rotating in the heating cylinder 82. While being sent, it is sent to the cylinder front chamber formed between the tip of the screw and the nozzle 85 and weighed. Here, an amount of molten resin necessary for filling the cavity 3, the runner 49, and the sprue 48 is measured.
As the raw material resin, a thermoplastic resin such as a polycarbonate resin or an acrylic resin generally used for molding this type of plastic lens can be used.

  In ST3, the mold is closed at the parting line PL. Specifically, when the toggle link mechanism 65 is driven to advance the cross head 73, the toggle links 71A and 71B extend, and the movable die plate 64 advances toward the fixed die plate 61. 50 molds are closed. At this time, a gap S is maintained in a state where the disc spring 17A interposed between the mold body 4 of the movable mold 1 and the mold mounting member 16 is not compressed, and the fixed mold 2 and the movable mold 1 are separated by the parting line PL. Close the mold. In this state, the gap S is set to the maximum opening amount.

  In ST4, the cavity volume is set. In ST3, the crosshead 73 is further advanced to a preset position (cavity volume setting position) from the state in which the movable mold 1 and the fixed mold 2 are brought into close contact with each other by the parting line PL. As a result, the toggle links 71A and 71B are extended, and the movable die plate 64 is moved toward the fixed die plate 61 and moved to the cavity expansion position. The cavity enlargement amount is determined by setting the crosshead position. As a result, the gap S of the mold 50 is reduced leaving the cavity enlargement. At this time, the volume (thickness) of the cavity 3 is larger than the lens volume (thickness) to be molded, that is, the thickness of the extracted molded product. Further, since the disc spring 17A is compressed, some clamping force is generated as the reaction force.

  In ST5, injection is performed. The molten resin weighed in ST2 is injected into the mold 50 through the passage of the injection nozzle 85. That is, the molten resin introduced into the heating cylinder 82 of the injection device 80 and weighed is injected. Then, molten resin is injected from a nozzle 85 formed at the tip of the heating cylinder 82 and filled into the cavity 3 through the sprue 48, the runner 49, and the gate G. When the molten resin is filled into the cavity 3, the injection speed is controlled to be constant.

  In ST6, the resin is sealed in the mold. After injecting a predetermined amount of resin at T5, the cross head 73 is further advanced immediately before the injection filling of the molten resin is completed. Then, after the injection filling is completed, the nozzle shut pin 91 is protruded into the sprue 48 by the nozzle shut mechanism 90 and the nozzle 85 is closed. Thereby, the filled molten resin is enclosed in the mold 50 in a compressed and pressurized state.

  In ST7, resin pressurization is performed. In ST6, the crosshead 73 starts to advance, and when the crosshead 73 advances to the origin (zero position) and stops, the toggle links 71A and 71B extend, so that the molten resin contained in the mold 51 is compressed. Pressed.

  In ST8, cooling is performed. For this purpose, the temperature of each part (insert, insert guide member, etc.) of the mold 50 is adjusted by the mold temperature adjusting device 51 so that the temperature is set to the Tg point or less according to the lens characteristics to be molded. Perform fluid temperature control. When the molten resin contained in the mold 50 is cooled while being compressed and pressurized, the raw material resin injected and filled in the cavity 3 is solidified as the cooling progresses in the compressed state. By contracting, a plastic lens having a predetermined volume is molded.

  In ST9, a release operation is performed. In the mold release operation, the crosshead 73 of the toggle link mechanism 65 is moved backward toward the rear plate 62 to open the mold 50.

  In ST10, a molded product ejecting operation is performed. When the cross head 73 is retracted to the end, the distance between the movable die plate 64 and the fixed die plate 61 is maximized, and the mold 50 is divided and opened by the parting line PL. When opening the mold, the eject rods 34 and 38 are advanced to take out the molded plastic lens.

  In manufacturing the plastic lens in the above procedure, in ST7, the movable die plate 64 further advances, and each hydraulic cylinder 19 provided in the die mounting member 16 moves the insert die 11 through the back insert 22. The insert mold 11 slides in the insert guide member 5 and presses and compresses the molten resin injected and filled in the cavity 3. In ST 10, the pressure receiving member 32, the hydraulic cylinder 19, the back insert 22 and the insert mold 11 are pressed by the eject rod 34, and the insert mold 11 slides in the insert guide member 5 and is molded in the cavity 3. It is designed to push out the lens.

  Thus, even after the insert mold 11 on the movable mold 1 side is housed in the insert guide member 5, the insert mold 11 repeatedly slides in the insert guide member 5 for each molding shot. In the insert mold 11 manufactured as described above, the outer peripheral surface of the glass substrate 11a has a constant width d along the circumferential direction and is located on the inner side of the outer peripheral surface of the base 11b. For this reason, even when the insert mold 11 is inclined with respect to the axial direction when sliding inside the insert guide member 5, the outer peripheral surface of the glass substrate 11 a contacts the inner peripheral surface of the insert guide member 5. This can be effectively avoided.

Therefore, not only the insert mold 12 on the fixed mold 2 side but also the insert mold 11 on the movable mold 1 side is joined to the base 11 b with the glass substrate 11 a formed with a molding surface for molding the optical surface of the lens. Thus, the optical lens mold can be used without any problem.
Therefore, by forming the molding surfaces of the insert molds 11 and 12 with the glass base materials 11a and 12a, the mold temperature during the injection molding can be set low in order to shorten the molding cycle. Due to the heat insulating effect of the glass base materials 11a and 12a, the temperature drop of the molten resin flowing into the cavity 3 can be suppressed. For this reason, it is possible to improve the productivity by reducing the cooling time by lowering the set temperature of the mold temperature while suppressing the appearance trouble due to the decrease in the viscosity during the flow of the molten resin. The base 11b can be made of a glass substrate 11a on which a molding surface for molding the optical surface of the lens is formed on both the insert mold 11 on the movable mold 1 side and the insert mold 12 on the fixed mold 2 side. By using an optical lens molding die that is joined, such an effect becomes more prominent.

  Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. Nor.

  When molding a plastic lens using an optical lens molding die formed by joining a glass substrate on which a molding surface for molding an optical surface of a lens is formed to a metal base, the present invention It can be used as a technique that can effectively avoid breakage.

1 Movable type (split type)
2 Fixed type (split type)
3 Cavities 11 and 12 Insert molds 11a and 12a Glass base materials 11b and 12b Pedestal 50 Mold 100 Assembly jig 101 Metal tape (filler)

Claims (5)

A method for producing an optical lens molding die, wherein a glass substrate on which a molding surface for molding a plastic lens having a predetermined lens shape is formed is bonded to a metal base,
Forming the glass substrate with a smaller diameter than the pedestal;
While installing the assembly jig in close contact with the outer peripheral surface of the pedestal,
The glass substrate is overlaid on the pedestal with a filler formed in a thickness matching the difference in diameter between the glass substrate and the pedestal sandwiched between the assembly jig and the glass substrate. And a method for manufacturing an optical lens molding die.   The manufacturing method of the optical lens shaping | molding die of Claim 1 which made the diameter difference of the said glass base material and the said base 5-50 micrometers.   The manufacturing method of the optical lens shaping | molding die as described in any one of Claims 1-2 which installs the said assembly jig | tool three or more at equal intervals along the outer peripheral surface of the said base.   The method for producing an optical lens molding die according to any one of claims 1 to 3, wherein the filler is a metal tape. In manufacturing a plastic lens having a predetermined lens shape by injecting and filling a molten raw material resin into a cavity formed between a pair of split molds,
An optical lens molding die is manufactured by the method according to any one of claims 1 to 4, and a raw material resin is provided in the cavity by using the optical lens molding die as at least one of the pair of split dies. A method of manufacturing a plastic lens, characterized by injection, filling and molding into a predetermined lens shape.

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