JP2008213195A - Resin lens and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the gap formed between the surface of a mold which demarcates cavities during molding and the surface of a resin lens being a molded product. <P>SOLUTION: In the manufacturing method of the resin lens using a casting method for heating and polymerizing a thermosetting liquid resin 7, a slide mold 3 is moved with respect to a fixed mold 1 and a movable mold 2 corresponding to the polymerization shrinkage of the liquid resin 7 during molding so that the volume of the cavity 4 demarcated by the fixed mold 1, the movable mold 2 and the slide mold 3 is reduced by the polymerization shrinkage quantity of the liquid resin 7 during molding. In detailed, the slide mold 3 for forming the plane of the lens 8 during heating polymerization is moved toward the fixed mold 1 for forming the protruded surface of the lens 8 corresponding to the polymerization shrinkage of the liquid resin 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resin lens using a casting method in which a thermosetting liquid resin is heated and polymerized, and a method for manufacturing the same, and in particular, a surface of a molding die that defines a cavity during molding and a lens as a molded product. The present invention relates to a resin lens that can reduce a gap generated between the surface of the lens and a manufacturing method thereof.

  Conventionally, a method for producing a resin lens using a casting method in which a thermosetting liquid resin is polymerized by heating is known. An example of a method for manufacturing this type of resin lens is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-144351. In the method for manufacturing a resin lens described in Japanese Patent Application Laid-Open No. 2002-144351, the liquid resin is appropriately heated in accordance with the progress of polymerization of the liquid resin, and thereby, in the cavity defined by the molding die. The reduced pressure state has been reduced.

  According to a casting method in which a thermosetting liquid resin is gradually heated and polymerized, distortion of a lens as a molded product can be reduced as compared with an injection molding method in which a molten resin is rapidly cooled and solidified.

  By the way, also in the casting method, since the liquid resin in the cavity undergoes polymerization shrinkage during molding, the volume of the lens as a molded product becomes smaller than the volume of the cavity.

  In the resin lens manufacturing method described in Japanese Patent Application Laid-Open No. 2002-144351, the reduced pressure state in the cavity is reduced during molding, but the volume of the cavity cannot be reduced. Therefore, in the resin lens manufacturing method described in JP-A-2002-144351, when the liquid resin in the cavity shrinks during molding, the surface of the molding die that defines the cavity and the lens as a molded product A large gap may be formed between the lens and the surface of the lens, and as a result, a large sink may occur in the lens.

JP 2002-144351 A

  In view of the above-described problems, the present invention provides a resin lens that can reduce a gap generated between the surface of a molding die that defines a cavity during molding and the surface of a lens as a molded product, and a method for manufacturing the same. The purpose is to provide.

  Specifically, an object of the present invention is to provide a resin lens for a vehicular lamp in which sink marks and internal distortion are reduced.

  According to the first aspect of the present invention, in the method of manufacturing a resin lens using a casting method in which a thermosetting liquid resin is heated and polymerized, the volume of the cavity defined by the molding die is During molding, the part for forming the lens flat surface is formed on the side of the part for forming the convex surface of the lens so that the polymerization shrinkage of the liquid resin is reduced. There is provided a method for producing a resin lens, wherein the resin lens is moved according to polymerization shrinkage.

  According to the second aspect of the present invention, the resin supply path extending from the injection unit to the cavity is blocked by a part of the molding die that is moved in accordance with the polymerization shrinkage of the liquid resin during molding. A method for producing a resin lens according to claim 1 is provided.

  According to the third aspect of the present invention, in the stage before the liquid resin in the resin supply path solidifies, the resin is moved by a part of the molding die that is moved in accordance with the polymerization shrinkage of the liquid resin during molding. The method for producing a resin lens according to claim 2, wherein the supply path is blocked.

  According to the fourth aspect of the present invention, the resin supply paths are arranged in a lattice pattern, and the cavity is disposed at the intersection of the vertically extending resin supply path and the laterally extending resin supply path. A method for producing a resin lens according to claim 3 is provided.

  According to the fifth aspect of the present invention, the lens body having a convex surface and a flat surface, the flange formed on the periphery of the lens main body, and the flange extending to the plane of the lens body. Volume of a cavity defined by a molding die in a resin lens of a vehicle lamp manufactured using a casting method in which a cylindrical holder portion is integrally molded and a thermosetting liquid resin is heated and polymerized However, the portion of the molding die for forming the plane of the lens body portion and the end surface of the holder portion during molding is reduced so as to reduce the polymerization shrinkage of the liquid resin during molding. A resin lens is provided which is formed by being moved in accordance with polymerization shrinkage of a liquid resin toward a portion for forming a convex surface.

  In the method for producing a resin lens according to claim 1, a casting method in which a thermosetting liquid resin is heated and polymerized is used. Furthermore, during molding, a part of the molding die is molded in response to the polymerization shrinkage of the liquid resin so that the volume of the cavity defined by the molding die is reduced by the polymerization shrinkage of the liquid resin being molded. It is moved relative to the rest of the mold.

  Therefore, according to the method for manufacturing a resin lens according to claim 1, it is possible to reduce a gap generated between the surface of the molding die that defines the cavity during molding and the surface of the lens as the molded product. it can.

  Specifically, in the method for manufacturing a resin lens according to claim 1, during molding, a portion for forming the lens plane of the molding die forms a convex surface of the lens. It is moved to the side of the portion according to the polymerization shrinkage of the liquid resin. That is, in the resin lens manufacturing method according to the first aspect, during the molding, the liquid resin is continuously pressed against the portion of the molding die for forming the convex surface of the lens.

  Therefore, according to the method for manufacturing a resin lens according to claim 1, the curve of the convex surface of the lens as a molded product and the portion of the molding die for forming the convex surface of the lens. The curvature can be made to substantially coincide.

  As a result, according to the method for manufacturing a resin lens according to claim 1, the curvature of the convex surface of the lens as a molded product and the lens of the molding die are caused by polymerization shrinkage of the liquid resin. Compared to the conventional case where the molding die was designed in consideration of the fact that the curvature of the part for forming the convex surface is different, the optical characteristics of the actually manufactured lens are designed lenses It is possible to approach the optical characteristics of In other words, according to the method for manufacturing a resin lens according to claim 2, the lens of the convex mold surface of the lens as a molded product and the molding die as the liquid resin is polymerized and contracted. To improve the dimensional accuracy of the actually manufactured lens, compared to the conventional case where the molding die was designed in consideration of the fact that the curvature of the part for forming the convex surface of the lens is different Can do.

  In the resin lens manufacturing method according to claim 2, the resin supply path extending from the injection unit to the cavity is blocked by a part of the molding die that is moved in accordance with the polymerization shrinkage of the liquid resin during molding. The Therefore, according to the resin lens manufacturing method of claim 2, the liquid resin in the cavity flows back to the injection unit when a part of the molding die is moved in accordance with the polymerization shrinkage of the liquid resin during molding. Can be prevented. Specifically, according to the method for manufacturing a resin lens according to claim 2, a part of the molding die is moved in accordance with the polymerization shrinkage of the liquid resin during molding without the need for providing a separate backflow prevention mechanism. In this case, it is possible to prevent the liquid resin in the cavity from flowing back to the injection unit.

  When the resin supply path is blocked by a part of the molding die that is moved in accordance with the polymerization shrinkage of the liquid resin during molding at a stage after the liquid resin in the resin supply path starts to solidify, it starts to solidify. The resin in the resin supply path is pushed by a part of the molding die, which may cause stress on the liquid resin in the cavity.

  In view of this point, in the method for manufacturing a resin lens according to claim 3, in the stage before the liquid resin in the resin supply path solidifies, the molding lens is moved in accordance with the polymerization shrinkage of the liquid resin during molding. The resin supply path is blocked by a part of the mold. Therefore, according to the method for manufacturing a resin lens according to the third aspect, it is possible to reduce the risk that stress is applied to the liquid resin in the cavity when the resin supply path is shut off.

  In the resin lens manufacturing method according to claim 4, the resin supply paths are arranged in a lattice shape, and a cavity is arranged at the intersection of the vertically extending resin supply path and the laterally extending resin supply path. ing. Therefore, according to the method for manufacturing a resin lens according to claim 4, the resin lens is molded by one molding die as compared with the case where the cavity is arranged at the tip of the radially arranged resin supply path. The number of lenses can be increased.

  6. A resin lens for a vehicular lamp according to claim 5, wherein a lens body portion having a convex surface and a flat surface, a flange portion formed on the periphery of the lens body portion, and a flange on the plane side of the lens body portion. A cylindrical holder part extending from the part is integrally formed and manufactured using a casting method in which a thermosetting liquid resin is heated and polymerized. Further, during molding, the plane of the lens body portion and the holder portion of the molding die are reduced so that the volume of the cavity defined by the molding die is reduced by the polymerization shrinkage of the liquid resin being molded. It is formed by moving the part for forming the end face to the part for forming the convex surface of the lens body in accordance with the polymerization shrinkage of the liquid resin. In other words, in the resin lens of the vehicular lamp according to the fifth aspect, during molding, the liquid resin is continuously pressed to a portion of the molding die for forming the convex surface of the lens body.

  Therefore, according to the resin lens of the vehicular lamp according to claim 5, the gap generated between the surface of the molding die that defines the cavity during molding and the surface of the lens as the molded product is reduced. Can do. Specifically, according to the resin lens of the vehicular lamp according to claim 5, sink marks and internal distortion that may occur in the resin lens during molding can be reduced.

  Hereinafter, a first embodiment of a method for producing a resin lens of the present invention will be described. FIG. 1 is a cross-sectional view of a manufacturing apparatus to which the method for manufacturing a resin lens according to the first embodiment is applied, and FIG. 2 is a cross-sectional view taken along line AA of FIG. 1 and 2, reference numeral 1 denotes a fixed side mold, 2 denotes a movable side mold configured to be movable in the vertical direction of FIG. 1 shows a slide mold configured to be further movable in the vertical direction of FIG. In the manufacturing apparatus of the first embodiment, a molding die for molding a resin lens by a casting method is constituted by a fixed side die 1, a movable side die 2, and a slide die 3.

  1 and 2, reference numeral 4 denotes a cavity defined by a fixed mold 1, a movable mold 2, and a slide mold 3 as molding dies. Reference numeral 5 denotes an injection unit for supplying a thermosetting liquid resin, and reference numeral 6 denotes a resin supply path extending from the injection unit 5 to the cavity 4.

  In the manufacturing apparatus according to the first embodiment, as shown in FIG. 2, the resin supply paths 6 are arranged in a lattice shape, and extend in the horizontal direction in FIG. 2 and the resin supply paths 6 extending in the vertical direction in FIG. The cavity 4 is disposed on the intersection with the resin supply path 6.

  FIG. 3 is a cross-sectional view showing a state where the thermosetting liquid resin 7 is supplied from the injection unit 5 and the cavity 4 and the resin supply path 6 are filled with the liquid resin. FIG. 4 is a cross-sectional view showing a state in which the slide mold 3 is moved to the fixed mold 1 side. FIG. 5 is a cross-sectional view showing a state in which the movable mold 2 and the slide mold 3 are separated from the fixed mold 1 and the lens 8 as a molded product can be taken out. FIG. 6 is a side view of the resin lens 8 molded by the manufacturing apparatus of the first embodiment. In FIG. 6, 8 a indicates the lens body portion of the resin lens 8, and 8 b indicates the flange portion of the resin lens 8.

  In the resin lens manufacturing method of the first embodiment, first, as shown in FIG. 3, a thermosetting liquid resin 7 is supplied from the injection unit 5, and liquid is supplied into the cavity 4 and the resin supply path 6. Resin 7 is filled. Next, pressure is applied from the injection unit 5 side so that the liquid resin 7 in the resin supply path 6 does not flow backward to the injection unit 5, and the pressure is maintained. Next, as shown in FIG. 4, the slide mold 3 is moved to the fixed mold 1 side (the lower side of FIG. 4). As a result, the resin supply path 6 is blocked by the slide mold 3. Specifically, in the resin lens manufacturing method of the first embodiment, the resin supply path 6 is blocked by the slide mold 3 before the liquid resin in the resin supply path 6 is solidified.

  Next, in the method for manufacturing a resin lens according to the first embodiment, the stationary mold 1 is heated so that the surface temperature of the cavity 4 is 80 to 150 ° C., and the thermosetting liquid resin in the cavity 4 is heated. 7 is gradually heat-cured and cured. Specifically, the heat polymerization is performed so that the volume of the cavity 4 defined by the fixed mold 1, the movable mold 2 and the slide mold 3 is reduced by the polymerization shrinkage of the liquid resin 7 during the heat polymerization. Inside, the slide mold 3 is moved to the lower side in FIG. 4 with respect to the fixed mold 1 and the movable mold 2 in accordance with the polymerization shrinkage of the liquid resin 7. In the method for manufacturing a resin lens according to the first embodiment, the slide amount of the slide mold 3 is set in advance so as to allow 10 to 20% of the volume of the cavity 4 as the polymerization shrinkage of the liquid resin 7 during heat polymerization. Yes.

  As a result, as shown in FIGS. 4 and 6, a resin lens 8 having a lens body 8a and a flange 8b is formed. Specifically, the convex surface of the lens body 8 a and the surface of the flange body 8 b on the lens body 8 a side are formed by the fixed mold 1. In addition, the flat surface on the opposite side of the lens body 8 a of the flange 8 b is formed by the slide mold 3.

  Next, in the method for manufacturing a resin lens according to the first embodiment, as shown in FIG. 5, the movable mold 2 and the slide mold 3 are separated from the fixed mold 1, and the lens 8 as a molded product is obtained. Is made removable. Next, the lens 8 is taken out from the fixed mold 1 by air suction or ejector pins (not shown).

  FIG. 7 is a view showing a vehicular lamp in which the lens 8 formed by the resin lens manufacturing method of the first embodiment is used. In FIG. 7, 9 indicates a lens holder, 10 indicates a light source, 11 indicates a reflector, and 12 indicates a shade. In the vehicle lamp shown in FIG. 7, the lens 8 is fixed to the lens holder 9 by using the flange portion 8 b.

  In the method for manufacturing a resin lens according to the first embodiment, as a thermosetting transparent resin 7 which is liquid at normal temperature, a radically polymerizable methyl methacrylate monomer or a mixture containing the monomer and methyl methacrylate are mainly used. A polymer in which the polymer of the monomer to be dissolved is used is used. In addition, as a necessary additive for the present composition, a radical polymerization initiator, an ultraviolet absorber such as UVA, HALS, an antioxidant, a release agent, and the like are used. As a medium for heating the cavity 4, a heater, warm water, or the like is used.

  In the resin lens manufacturing method according to the second embodiment, instead of methyl methacrylate, a radically polymerizable silicone-based monomer or a mixture containing the monomer and a monomer-based polymer of silicone are dissolved. It is also possible to use the one in the state. As an additive, the thing similar to the manufacturing method of the resin-made lens of 1st Embodiment is used.

  In other words, in the method for manufacturing a resin lens according to the first embodiment, a casting method in which the thermosetting liquid resin 7 is heated and polymerized is used. Furthermore, as shown in FIG. 4, the volume of the cavity 4 defined by the fixed side mold 1, the movable side mold 2 and the slide mold 3 as the molding mold is the polymerization of the liquid resin 7 being molded. During the molding, the slide mold 3 is moved relative to the stationary mold 1 and the movable mold 2 in accordance with the polymerization shrinkage of the liquid resin 7 so as to decrease by the shrinkage. Therefore, according to the resin lens manufacturing method of the first embodiment, a gap generated between the surface of the fixed mold 1 that defines the cavity 4 and the surface of the lens 8 as a molded product during molding is reduced. can do.

  Furthermore, in the method for manufacturing a resin lens according to the first embodiment, as shown in FIG. 4, during molding, the fixed side mold 1, the movable side mold 2, and the slide mold 3 as molding molds are molded. Among them, the slide mold 3 for forming the plane of the lens 8 is moved to the side of the fixed mold 1 for forming the convex surface of the lens 8 according to the polymerization shrinkage of the liquid resin 7. That is, in the manufacturing method of the resin lens according to the first embodiment, the convex shape of the lens 8 among the fixed side mold 1, the movable side mold 2 and the slide mold 3 as molding dies during molding. The liquid resin 7 is continuously pressed against the fixed mold 1 for forming the surface. Therefore, according to the resin lens manufacturing method of the first embodiment, the convex surface of the lens 8 as a molded product and the convex surface of the lens 8 among the fixed mold 1 are formed. It is possible to substantially match the curvature of this part.

  As a result, according to the resin lens manufacturing method of the first embodiment, with the polymerization shrinkage of the liquid resin, the curvature of the convex surface of the lens 8 as a molded product, and the fixed mold 1, The optical characteristics of the actually manufactured lens are designed rather than the conventional case where the molding die is designed in consideration of the fact that the curvature of the portion for forming the convex surface of the lens 8 is different. The optical characteristics of the upper lens can be approached. In other words, according to the resin lens manufacturing method of the first embodiment, the dimensional accuracy of the lens 8 can be improved.

  In the resin lens manufacturing method of the first embodiment, as shown in FIG. 4, the resin supply path 6 extending from the injection unit 5 to the cavity 4 responds to polymerization shrinkage of the liquid resin 7 during molding. It is blocked by a slide mold 3 that can be moved in this manner. Therefore, according to the resin lens manufacturing method of the first embodiment, the liquid resin 7 in the cavity 4 is injected into the injection unit 5 when the slide mold 3 is moved in accordance with the polymerization shrinkage of the liquid resin 7 during molding. It is possible to prevent backflow.

  Specifically, in the resin lens manufacturing method of the first embodiment, the resin supply path 6 is blocked by the slide mold 3 before the liquid resin 7 in the resin supply path 6 is solidified. Therefore, according to the resin lens manufacturing method of the first embodiment, it is possible to reduce the risk that stress is applied to the liquid resin 7 in the cavity 4 when the resin supply path 6 is shut off.

  Further, in the method for manufacturing a resin lens according to the first embodiment, as shown in FIG. 2, the resin supply paths 6 are arranged in a lattice shape, and the resin supply paths 6 extending vertically and the resin extending horizontally are arranged. The cavity 4 is arranged on the intersection with the supply path 6. Therefore, according to the resin lens manufacturing method of the first embodiment, the molding is performed by one molding die as compared with the case where the cavity is arranged at the tip of the radially arranged resin supply path. The number of lenses 8 can be increased.

  Hereinafter, a third embodiment of the resin lens manufacturing method of the present invention will be described. FIG. 8 is a cross-sectional view of a manufacturing apparatus to which the method for manufacturing a resin lens according to the third embodiment is applied. FIG. 9 is a cross-sectional view showing a state in which the thermosetting liquid resin 7 is supplied from the injection unit 5 and the liquid resin is filled in the cavity 4 ′ and the resin supply path 6. FIG. 10 is a cross-sectional view showing a state in which the slide mold 3 is moved to the fixed mold 1 side. FIG. 11 is a cross-sectional view showing a state where the movable mold 2 and the slide mold 3 are separated from the fixed mold 1 and the lens 8 ′ as a molded product can be taken out.

  FIG. 12 is a view showing a resin lens 8 ′ formed by the manufacturing apparatus of the third embodiment. Specifically, FIG. 12A is a side view of the resin lens 8 ′, FIG. 12B is a cross-sectional view of the resin lens 8 ′, and FIG. 12C is a rear view of the resin lens 8 ′. . FIG. 13 is a view showing a vehicular lamp using a lens 8 ′ molded by the resin lens manufacturing method of the third embodiment. In FIGS. 12 and 13, 8 a ′ represents a lens body portion of the resin lens 8 ′, and 8 b ′ represents a cylindrical holder portion formed integrally with the lens body portion 8 a ′. Reference numeral 8 b 1 ′ denotes a fastening portion used for fastening the reflector 11 in the holder portion 8 b ′. As shown in FIGS. 12 and 13, in the lens 8 ′ molded by the resin lens manufacturing method of the third embodiment, the cylindrical holder portion 8 b ′ is on the plane side of the lens body portion 8 a ′ ( 12B and the right side of FIG. 13) extend from the flange portion 8b (see FIG. 6).

  In the manufacturing apparatus of the third embodiment, similarly to the manufacturing apparatus of the first embodiment shown in FIG. 2, the resin supply paths 6 are arranged in a lattice shape and extend in the vertical direction. A cavity 4 ′ is arranged on the intersection with the resin supply path 6 extending in the direction.

  In the resin lens manufacturing method of the first embodiment, as shown in FIGS. 4 to 6, the outer diameter of the slide mold 3 and the outer diameter of the flange portion 8 b of the lens 8 are substantially equal. In the method of manufacturing a resin lens according to the third embodiment, as shown in FIGS. 10 to 12, the outer diameter of the distal end portion (lower end portion of FIGS. 10 and 11) of the slide mold 3 is the lens 8. The outer diameter of the 'holder portion 8b' is made smaller. Therefore, in the method for manufacturing a resin lens according to the third embodiment, the lens 8 is formed by the liquid resin 7 disposed between the inner peripheral surface of the fixed mold 1 and the outer peripheral surface of the distal end portion of the slide mold 3. A 'holder portion 8b' is formed. Specifically, the main body 8a 'and the holder 8b' of the lens 8 'are integrally formed.

  In the method for manufacturing a resin lens according to the third embodiment, first, as shown in FIG. 9, a thermosetting liquid resin 7 is supplied from the injection unit 5 and enters the cavity 4 ′ and the resin supply path 6. Liquid resin 7 is filled. Next, pressure is applied from the injection unit 5 side so that the liquid resin 7 in the resin supply path 6 does not flow backward to the injection unit 5, and the pressure is maintained. Next, as shown in FIG. 10, the slide mold 3 is moved to the fixed mold 1 side (the lower side in FIG. 10). As a result, the resin supply path 6 is blocked by the slide mold 3. Specifically, in the method for manufacturing a resin lens according to the third embodiment, similar to the method for manufacturing a resin lens according to the first embodiment, the liquid resin in the resin supply path 6 is in a stage before solidifying, The resin supply path 6 is blocked by the slide mold 3.

  Next, in the method for manufacturing a resin lens according to the third embodiment, the stationary mold 1 is heated so that the surface temperature of the cavity 4 ′ becomes 80 to 150 ° C., and the thermosetting in the cavity 4 ′ is performed. The liquid resin 7 is gradually heated and polymerized and cured. Specifically, the heating is performed so that the volume of the cavity 4 ′ defined by the fixed side mold 1, the movable side mold 2, and the slide mold 3 is reduced by the polymerization shrinkage of the liquid resin 7 during the heating polymerization. During the polymerization, the slide mold 3 is moved to the lower side in FIG. 10 with respect to the fixed mold 1 and the movable mold 2 in accordance with the polymerization shrinkage of the liquid resin 7. In the method for manufacturing a resin lens according to the third embodiment, the slide amount of the slide mold 3 is set in advance in anticipation of 10 to 20% of the volume of the cavity 4 ′ as the polymerization shrinkage of the liquid resin 7 during heat polymerization. ing.

  As a result, as shown in FIGS. 10 and 12, a resin lens 8 'having a lens body 8a' and a holder 8b 'is formed. Specifically, the convex surface of the lens body 8 a ′ and the plane and outer peripheral surface of the holder 8 b ′ on the lens body 8 a ′ side are formed by the fixed mold 1. Further, the plane on the holder portion 8 b ′ side of the lens body portion 8 a ′ and the end surface and inner peripheral surface of the holder portion 8 b ′ are formed by the slide mold 3. Specifically, in the method for manufacturing a resin lens according to the third embodiment, as shown in FIGS. 8, 10, and 12, when the slide mold 3 finishes sliding, The portion forming the end surface of the holder portion 8b ′ is located below the lower end of the resin supply path 6 (lower side in FIG. 10).

  Next, in the method for manufacturing a resin lens according to the third embodiment, as shown in FIG. 11, the movable mold 2 and the slide mold 3 are separated from the fixed mold 1, and the lens 8 as a molded product is obtained. 'Is made available for retrieval. Next, the lens 8 ′ is taken out from the fixed mold 1 by air suction or ejector pins (not shown).

  In the vehicular lamp using the lens 8 ′ manufactured by the resin lens manufacturing method of the third embodiment, as shown in FIGS. 12 and 13, a fastening portion 8b1 of the holder portion 8b ′ of the lens 8 ′. The lens 8 ′ is fixed to the reflector 11 by using “. That is, in the vehicular lamp using the lens 8 ′ manufactured by the resin lens manufacturing method of the third embodiment, the lens 8 ′ manufactured by the resin lens manufacturing method of the first embodiment is used. Therefore, the number of parts can be reduced as compared with the vehicular lamp, and the assembly process of the lens 8 and the lens holder 9 can be eliminated.

  The resin lens 8 ′ of the vehicular lamp manufactured by the method for manufacturing a resin lens according to the third embodiment is molded using a casting method, and the cavity volume defined by the molding die is molded. It is formed so as to decrease by the polymerization shrinkage of the liquid resin inside. That is, in the resin lens 8 ′ of the vehicular lamp manufactured by the resin lens manufacturing method of the third embodiment, a predetermined pressure is applied to the entire resin lens 8 ′ by the molding die when the resin is cured. It continues to be added. Therefore, sink marks generated in the resin lens 8 ′ and internal distortion remaining in the resin lens 8 ′ after molding are significantly reduced.

  It is possible to evaluate the internal distortion of the resin lens 8 ′ by sandwiching the resin lens 8 ′ between the polarizing plates whose polarization axes are crossed and observing the resin lens 8 ′ while passing through the polarizing plate. it can. As a result of evaluation, a vehicle manufactured by the method for manufacturing a resin lens according to the third embodiment is compared with a case where the cavity volume defined by the molding die cannot be reduced by the polymerization shrinkage of the liquid resin being molded. The internal distortion of the resin lens 8 ′ of the lamp was significantly reduced. That is, according to the resin lens manufacturing method of the third embodiment, the reliability of the resin lens 8 'of the vehicle lamp can be dramatically improved.

  In the fourth embodiment, the first to third embodiments described above can be appropriately combined.

It is sectional drawing of the manufacturing apparatus with which the manufacturing method of the resin-made lenses of 1st Embodiment is applied. It is sectional drawing along the AA line of FIG. FIG. 3 is a cross-sectional view showing a state in which a thermosetting liquid resin 7 is supplied from an injection unit 5 and the cavity 4 and the resin supply path 6 are filled with the liquid resin. FIG. 5 is a cross-sectional view showing a state in which the slide mold 3 is moved to the fixed mold 1 side. FIG. 3 is a cross-sectional view showing a state in which a movable mold 2 and a slide mold 3 are separated from a fixed mold 1 and a lens 8 as a molded product can be taken out. It is a side view of the resin-made lens 8 shape | molded by the manufacturing apparatus of 1st Embodiment. It is the figure which showed the vehicle lamp using the lens 8 shape | molded by the manufacturing method of the resin-made lens of 1st Embodiment. It is sectional drawing of the manufacturing apparatus with which the manufacturing method of the resin-made lenses of 3rd Embodiment is applied. FIG. 4 is a cross-sectional view showing a state in which a thermosetting liquid resin 7 is supplied from an injection unit 5 and a liquid resin is filled in a cavity 4 ′ and a resin supply path 6. FIG. 5 is a cross-sectional view showing a state in which the slide mold 3 is moved to the fixed mold 1 side. FIG. 3 is a cross-sectional view showing a state in which a movable mold 2 and a slide mold 3 are separated from a fixed mold 1 and a lens 8 ′ as a molded product can be taken out. It is the figure which showed resin-made lens 8 'shape | molded by the manufacturing apparatus of 3rd Embodiment. It is the figure which showed the vehicle lamp using the lens 8 'shape | molded by the manufacturing method of the resin-made lens of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixed side mold 2 Movable side mold 3 Slide mold 4 Cavity 5 Injection unit 6 Resin supply path 7 Resin 8 Lens

Claims (5)

  In a resin lens manufacturing method using a casting method in which a thermosetting liquid resin is heated and polymerized, the volume of the cavity defined by the molding die is reduced by the polymerization shrinkage of the liquid resin during molding. During molding, the part for forming the lens plane of the molding die is moved to the part for forming the convex surface of the lens in accordance with the polymerization shrinkage of the liquid resin. A method for producing a resin lens.   2. The resin lens according to claim 1, wherein the resin supply path extending from the injection unit to the cavity is blocked by a part of a molding die that is moved in accordance with polymerization shrinkage of the liquid resin during molding. Manufacturing method.   The resin supply path is blocked by a part of a molding die that is moved in accordance with polymerization shrinkage of the liquid resin during molding before the liquid resin in the resin supply path is solidified. Item 3. A method for producing a resin lens according to Item 2.   4. The resin lens according to claim 3, wherein the resin supply paths are arranged in a lattice shape, and a cavity is disposed at an intersection of the resin supply path extending vertically and the resin supply path extending horizontally. Manufacturing method. A lens body portion having a convex surface and a flat surface, a flange portion formed on the periphery of the lens body portion, and a cylindrical holder portion extending from the flange portion on the flat surface side of the lens body portion are integrally formed. In a resin lens of a vehicle lamp manufactured using a casting method in which a thermosetting liquid resin is heated and polymerized,
During molding, the plane of the lens body portion and the end surface of the holder portion of the molding die are arranged so that the volume of the cavity defined by the molding die is reduced by the polymerization shrinkage of the liquid resin being molded. A resin lens formed by moving a portion to be formed toward a portion for forming a convex surface of a lens main body according to polymerization shrinkage of a liquid resin.

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