JP2011246314A - Upper mold for droplet-molding, optical element and method for producing optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an upper mold for droplet-molding where the falling of the temperature of a droplet caused by contacting the droplet with a mold is prevented, the molding accuracy of an optical element is enhanced by sufficiently applying pressing force to the droplet in the center of the mold and the thickness of the optical element is thinned, the optical element and a method for producing the optical element.SOLUTION: A plurality of the optical elements are obtained by press-molding the droplets of a gob which is a material to be molded using a lower mold where a plurality of optical surfaces are formed and the upper mold 1 for the droplet-molding where a plurality of the optical surfaces 11 are formed. The upper mold 1 for the droplet-molding where the falling of the temperature of the droplet caused by contacting the droplet with the mold is prevented, the molding accuracy of the optical element is enhanced by sufficiently applying the pressing force to the droplet on the center of the mold, and the thickness of the optical element is thinned, by having an escape part 13 with such a depth that a surplus material for molding which flows in during press-molding does not reach a deepest part between a plurality of the optical surfaces 11 formed on the upper mold 1, is provided. The optical element and the method for producing the optical element are also provided.

Description

  The present invention relates to an upper mold for forming a droplet, an optical element, and a method for manufacturing the optical element, and in particular, an upper part for forming a droplet to obtain a plurality of optical elements by press-molding a droplet of a batch of molding material. The present invention relates to a mold, an optical element, and a method for manufacturing the optical element.

  In recent years, production of optical elements by press molding has been actively performed. In particular, in order to mass-produce small optical elements such as photographing lenses for mobile phone cameras and optical elements for optical pickups, a multi-unit that obtains a large number of optical elements at a time by press-molding a batch of molding material Molding is performed by resin injection molding or the like.

  However, in the case of droplet molding in which droplets of a molding material are dropped onto a lower mold and press-molded, the liquid is brought into contact with the mold from the dropping of the droplets onto the lower mold until the press molding is completed. Drops are cooled. In particular, in the case of multi-molding in which a large number of optical surface portions that are transferred and serve as the optical surface of the optical element are arranged in a mold, the dropped liquid droplets have a raised shape at the center of the mold. Since it cannot be formed without extruding a large-thickness liquid droplet to the outside, the liquid droplet is cooled during the process and cannot be sufficiently pressed, resulting in a problem that the core thickness of the optical element increases.

  For example, in Patent Document 1, when a glass lens array is manufactured by reheat (reheat) molding, a sufficient pressing force can be obtained by allowing an excessive molding material to flow into a gap provided in a lens connecting member or a lower mold. A method for improving the molding accuracy of the lens array is proposed.

JP 2004-149369 A

  In the case of reheat molding, since the mold and the material to be molded are molded at substantially the same temperature or the mold is set at a higher temperature, it can be molded by the method of Patent Document 1. However, in the case of droplet forming, generally, the temperature of the droplet of the molding material (about 800 ° C.) is higher than the temperature of the mold (about 400 ° C.). In this case, the droplets are cooled by the contact between the droplets and the mold, and cannot be molded.

  The present invention has been made in view of the above circumstances, and prevents a drop in the drop temperature due to contact between the mold and the drop, and applies a sufficient pressing force to the drop at the center of the mold to provide an optical element. An object of the present invention is to provide an upper mold for forming a droplet, an optical element, and a method for manufacturing the optical element that can improve the molding accuracy of the optical element and reduce the thickness of the optical element.

  The object of the present invention can be achieved by the following constitution.

1. A lower mold having a plurality of optical surface portions formed thereon and an upper mold having a plurality of optical surface portions formed thereon, press-molding a batch of material droplets dropped onto the lower mold, An upper mold for droplet forming to obtain an optical element,
Provided with an escape portion for allowing excess molding material to escape between the plurality of optical surface portions,
The upper part for forming a droplet, wherein the escape part has a depth or a volume so that an excessive molding material flowing in during press molding does not reach the deepest part of the escape part.

  2. The depth or volume of the relief portion provided in the vicinity of the position facing the droplet dropping position of the batch of molding material is the depth or volume of the relief portion provided at a position away from the position facing the dropping position. 2. The upper mold for forming droplets according to 1 above, which is larger than depth or volume.

  3. The relief portion has a tapered portion on a side close to the surface facing the lower mold, and the tapered portion has a depth or volume such that the excessive material to be molded does not reach the deepest portion of the relief portion. 3. The upper mold for forming a droplet according to 1 or 2 above, wherein the upper mold is used.

  4). It is obtained by press-molding a batch of molding material droplets using the lower mold in which a plurality of optical surface portions are formed and the upper mold described in any one of 1 to 3 above. An optical element.

5). A molding step of press-molding a batch of droplets of a molding material using the lower mold in which a plurality of optical surface portions are formed and the upper mold according to any one of 1 to 3,
An optical element manufacturing method comprising: an optical element separation step of separating the plurality of optical elements obtained in the molding step into individual optical elements.

  According to the present invention, a plurality of optical elements are obtained by press-molding a batch of droplets of a molding material with a lower mold having a plurality of optical surface portions and an upper mold having a plurality of optical surface portions. In the upper mold for droplet forming, a relief part having a depth so that an excessive molding material flowing in at the time of press molding does not reach the deepest part is provided between a plurality of optical surface parts formed in the upper mold. Prevents the drop temperature from dropping due to contact between the mold and the liquid droplets, and applies sufficient pressing force to the liquid droplets in the center of the mold to improve the molding accuracy of the optical element, and the thickness of the optical element. It is possible to provide an upper mold for forming a droplet, an optical element, and a method for manufacturing the optical element.

It is a schematic diagram which shows the structure of 1st Embodiment of the upper mold | type for droplet shaping | molding. It is process drawing which shows the process of press molding using 1st Embodiment of an upper mold | type. It is a schematic diagram which shows each process of FIG. It is a schematic diagram which shows the structure of 2nd Embodiment of the upper mold | type for droplet shaping | molding. It is a schematic diagram which shows the structure of 3rd Embodiment of the upper mold | type for droplet shaping | molding. It is a schematic diagram which shows the structure of 4th Embodiment of the upper mold | type for droplet shaping | molding.

  Hereinafter, the present invention will be described based on the illustrated embodiment, but the present invention is not limited to the embodiment. In the drawings, the same or equivalent parts are denoted by the same reference numerals, and redundant description may be omitted.

  First, a first embodiment of an upper mold for forming glass droplets to which the present invention is applied will be described with reference to FIG. 1. FIG. 1 shows a first embodiment of an upper mold for forming droplets. FIG. 1A is a schematic view showing a configuration of a form, FIG. 1A is a plan view of a molding surface of an upper mold, and FIG.

  In FIG. 1, an upper mold 1 includes a plurality of (here, nine) optical surface portions 11 that are transferred to become optical surfaces of an optical element, and a relief portion 13 through which an excessive molding material flows during press molding, And a surface 15 facing the lower mold. The depth or volume of the escape portion 13 is set to a size such that an excessive material to be molded that flows during press molding does not reach the deepest portion of the escape portion 13. It is preferable that at least the side surface of the portion into which the surplus molding material flows in the escape portion 13 has a drawing taper and surface roughness necessary for releasing the cured surplus molding material. The bottom surface of the escape portion 13 does not require fine surface roughness.

  The material of the upper mold 1 and the lower mold 2 described later is required to have various properties such as being difficult to react with the material to be molded (glass in the present embodiment), being difficult to oxidize, and obtaining a good mirror surface. It is done. Examples of materials having these properties include various heat-resistant alloys (such as stainless steel), cemented carbides mainly composed of tungsten carbide, various ceramics such as carbide and nitride (such as silicon carbide, silicon nitride, and aluminum nitride), carbon Or a composite material thereof. Moreover, it is also preferable to use what formed thin films, such as various metals, ceramics, and carbon, on the surface of these materials. The upper mold 1 and the lower mold 2 may be made of the same material or different materials.

  In addition, the plurality of optical surface portions 11 of the upper mold 1 and the plurality of optical surface portions 21 of the lower mold 2 described later are preferably formed on one member from the viewpoint of relative positional accuracy. It may be composed of a plurality of members.

  Next, the press molding process using the first embodiment of the upper mold will be described with reference to FIGS. FIG. 2 is a process diagram showing a press molding process using the first embodiment of the upper die. FIG. 3 is a schematic diagram showing each step of FIG.

Process S1 (molding process)
This is a step of molding the optical element 31, and is composed of steps S11 to S14.

Step S11 (droplet dropping step)
This is a step of dropping a lump of droplets 3 on the lower mold 2. FIG. 3A shows a state in which a single droplet 3 is dropped on the lower mold 2.

  3A, the lower mold 2 is provided at a position facing the optical surface section 11 of the upper mold 1 (not shown), and a plurality of optical surface sections 21 that are transferred to become the optical surface of the optical element 31, and the upper mold And the opposite surface 23 and the like. On the plurality of optical surface portions 21 of the lower mold 2, a lump 3 of the molding material is dropped by a dropping device (not shown). As described above, the droplet 3 has a shape in which the portion dropped on the central portion of the lower mold 2 is raised. The temperature of the dropped droplet 3 is about 800 ° C., and the temperature of the lower mold 2 is about 400 ° C.

  As the molding material, for example, a known optical glass such as borosilicate glass, silicate glass, phosphate glass, or lanthanum glass, or a known optical resin such as polycarbonate can be used.

Process S12 (press molding process)
This is a step of press-molding the droplet 3 with the upper mold 1 and the lower mold 2. The state at the time of press molding is shown in FIG.

  In FIG. 3B, the optical surface portion 11 of the upper die 1 and the optical surface portion of the lower die 2 are formed by press-molding the dropped droplet 3 of the molding material with the upper die 1 and the lower die 2. An optical element 31 is formed in a region sandwiched between 21 and 21. The droplets between the optical elements 31 are brought into contact with the upper mold 1 and the lower mold 2 to be rapidly cooled to become the edge surface 35. The molding material 33 flows into a region sandwiched between the escape portion 13 of the upper mold 1 and the facing surface 23 of the lower mold 2.

  Since the depth or volume of the escape portion 13 is formed in such a size that the surplus molding material 33 that flows in does not reach the deepest portion of the escape portion 13, the upper die 1 and the lower die 2 are opposed to each other. The pressing can be performed until the surface 15 and the facing surface 23 are substantially in contact with each other, and the limit of how much the edge surface 35 between the optical elements 31 can be reduced can be broken. Furthermore, since the contact area between the droplet 3 and the upper mold 1 can be reduced by providing the escape portion 13, the temperature drop of the droplet 3 during press molding can be reduced. A sufficient pressing force can be applied to accurately transfer the surface shape of the optical surface, and the external dimension accuracy of the optical element 31 can be improved.

Step S13 (mold separation step)
This is a step of separating the upper mold 1 and the lower mold 2.

  As shown in FIG. 3B, when the press molding is completed, the hardened surplus molding material 33 flows into only the middle of the escape portion 13, so the hardened surplus molding material 33 easily escapes. The mold can be released from the portion 13.

Process S14 (mold release process)
This is a step of removing the optical element array 30 in which the optical element 31 and the hardened excess molding material 33 are connected by the edge surface 35 from the upper mold 1 or the lower mold 2. The shape of the removed optical element array 30 is shown in FIG.

Step S2 (optical element separation step)
In the step of separating the optical element array 30 obtained in step S1 (molding step) into individual optical elements 31, the step is composed of steps S21 and S22.

Step S21 (optical element cutting step)
This is a step of cutting into individual optical elements 31 from the optical element array 30 obtained in step S1 (molding step). For example, in the case of a plurality of optical elements 31 formed using the first embodiment of the upper mold shown in FIG. 1, by inserting a blade into the edge surface 35 between the optical elements 31, individual optical elements 31 are formed. The element 31 can be cut. At this time, the hardened excess molding material 33 is separated from the optical element 31 and removed.

Process S22 (deburring process)
In this step, the edge 35 remaining around the cut optical element 31 is removed. The edge surface 35 remaining around each cut optical element 31 is removed using, for example, a grinder.

  In step S21 (optical element cutting step), it is possible to omit step S22 by removing unnecessary portions such as the edge surface 35 and the hardened excess molding material 33 using a dicer, for example. .

  Through the above steps, a plurality of optical elements 31 are obtained from a single batch of the droplets 3 of the molding material by multi-molding. 2 is not limited to press molding using the first embodiment of the upper mold, but is common to press molding using all of the embodiments described below. Is applicable.

  As described above, according to the first embodiment of the upper mold for forming droplets, the excessive molding material that flows in during press molding is the deepest portion between the plurality of optical surface sections formed on the upper mold. By providing a relief part with a depth or volume that does not reach the surface, the drop temperature is prevented from decreasing due to contact between the mold and the droplet, and sufficient pressure is applied to the droplet at the center of the mold. In addition, it is possible to provide an upper mold for forming a droplet, an optical element, and a method for manufacturing the optical element that can improve the molding accuracy of the optical element and reduce the thickness of the optical element.

  Next, a second embodiment of the upper mold for forming a droplet according to the present invention will be described with reference to FIG. 4. FIG. 4 shows the configuration of the second embodiment of the upper mold for forming a droplet. 4A is a plan view of the molding surface of the upper mold, and FIG. 4B is a cross-sectional view taken along the line BB ′ of FIG. 4A.

  In FIG. 4, an upper mold 1 includes a plurality of (here, nine) optical surface portions 11 to be transferred and serving as optical surfaces of optical elements, and escape portions 13c and 13p for allowing excess molding material to flow in during press molding. And a surface 15 facing the lower mold. The depth or volume of the escape portions 13c and 13p is set to a size such that an excessive material to be molded that flows during press molding does not reach the deepest portion of the escape portions 13c and 13p.

  Further, as shown in FIG. 3A, a single droplet 3 of the molding material is dropped on the center of the lower mold 2, and the droplet 3 has a portion dropped on the center of the lower mold 2. It becomes a raised shape. Therefore, the depth or the volume of the escape portion 13c provided in the upper mold 1 opposite to the dropping position of the lower mold 1, that is, in the vicinity of the center of the upper mold 1, is the relief provided in a position away from the dropping position. It is formed larger than the depth or volume of the portion 13p.

  By enlarging the escape portion 13c in the vicinity of the center of the upper die 1, even if a large amount of excess molding material 33 swelled in the central portion of the lower die 2 flows into the deepest portion of the escape portion 13c, The upper mold 1 and the lower mold 2 can be pressed until the opposed surface 15 and the opposed surface 23 substantially come into contact with each other, breaking the limit of how thin the edge surface 35 between the optical elements 31 can be made. Can do.

  As described above, according to the second embodiment of the upper mold for droplet forming, the relief portion provided in the vicinity of the position of the upper mold facing the droplet dropping position of the batch of molding material. The depth or volume is made larger than the depth or volume of the relief provided at a position away from the position opposite to the dropping position, thereby preventing drop temperature drop due to contact between the mold and the drop. In addition, a sufficient pressing force is applied to the droplets in the center of the mold to improve the molding accuracy of the optical element, and the thickness of the optical element can be reduced. An element manufacturing method can be provided.

  Next, a third embodiment of the upper mold for forming a droplet according to the present invention will be described with reference to FIG. 5. FIG. 5 shows the configuration of the third embodiment of the upper mold for forming a droplet. FIG. 5A is a plan view of the molding surface of the upper mold, and FIG. 5B is a cross-sectional view taken along the line CC ′ of FIG.

  In FIG. 5, an upper mold 1 is provided with a plurality of (six in this case) optical surface portions 11 to be transferred to become optical surfaces of optical elements, and an excessive molding target provided at the center of the upper mold 1 during press molding. The escape part 13 for the material 33 to flow in, and the opposing surface 15 etc. with a lower mold | type are provided. The depth or volume of the escape portion 13 is set to a size such that an excessive molding material 33 that flows in during press molding does not reach the deepest portion of the escape portion 13.

  The depth or volume of the relief portion 13 at the center of the upper die 1 is set to a size such that an excessive material to be molded does not reach the deepest portion of the relief portion 13, so that it rises at the center of the lower die 2. Even if a large amount of surplus molding material 33 flows in, it does not reach the deepest part of the escape portion 13, so the upper mold 1 and the lower mold 2 are pressed until the opposed surface 15 and the opposed surface 23 are substantially in contact with each other. It is possible to break the limit of how thin the edge surface 35 between the optical elements 31 can be made.

  As described above, according to the third embodiment of the upper mold for droplet forming, the depth or volume of the escape portion provided in the central portion of the upper die is set so that the surplus molding material is the By setting the size so that it does not reach the deepest part, the drop temperature drop due to contact between the mold and the droplet is prevented, and sufficient pressure is applied to the droplet in the center of the mold to make the optical It is possible to provide an upper mold for forming a droplet, an optical element, and a method of manufacturing the optical element that can improve the molding accuracy of the element and reduce the thickness of the optical element.

  Next, a fourth embodiment of the upper mold for forming a droplet in the present invention will be described with reference to FIG. 6. FIG. 6 shows the configuration of the fourth embodiment of the upper mold for forming a droplet. FIG. 6A is a plan view of the molding surface of the upper mold, and FIG. 6B is a cross-sectional view taken along the line DD ′ of FIG.

  In FIG. 6, an upper mold 1 includes a plurality of (four in this case) optical surface portions 11 that are transferred to become the optical surfaces of the optical elements, and an excessive molding material provided around the optical surface portions 11 during press molding. 33 is provided with an escape portion 13 for inflow of 33, an opposing surface 15 of the lower mold, and the like. The escape portion 13 includes a taper portion 13t and a deepest portion 13b, and the depth or volume of the taper portion 13t is set to a size such that an excessive material to be molded that flows during press molding does not reach the deepest portion 13b. Has been.

  By setting the depth or volume of the tapered portion 13t of the escape portion 13 to such a size that the excessive material to be molded does not reach the deepest portion 13b, a large amount of excessively covered material that rises in the central portion of the lower mold 2 is obtained. Even if the molding material 33 flows in, it does not reach the deepest part 13b, so that the upper mold 1 and the lower mold 2 can be pressed until the opposed surface 15 and the opposed surface 23 substantially come into contact with each other. You can break the limit of how thin the thickness can be. Moreover, since it is not necessary to process the surface of the deepest part 13b into the drawing taper and surface roughness required for mold release of the hardened | cured surplus molding material 33, metal mold | die processing becomes easy.

  As described above, according to the fourth embodiment of the upper mold for droplet forming, the escape portion 13 is constituted by the tapered portion 13t and the deepest portion 13b, and the depth or volume of the tapered portion 13t is press-molded. By setting the size so that the excessive molding material that sometimes flows in does not reach the deepest portion 13b, a drop in the temperature of the droplet due to the contact between the mold and the droplet can be prevented, and the droplet at the center of the mold can be prevented. In addition, it is possible to improve the molding accuracy of the optical element by applying sufficient pressing force, and to provide an upper mold for forming a droplet, an optical element, and a method for manufacturing the optical element that can reduce the thickness of the optical element. it can.

  As described above, according to the present invention, a batch of droplets of a molding material is press-molded by a lower mold having a plurality of optical surface portions and an upper mold having a plurality of optical surface portions. This is the upper mold for droplet forming to obtain a plurality of optical elements, and the depth at which the excess molding material flowing in during press molding does not reach the deepest part between the plurality of optical surface parts formed on the upper mold Equipped with a relief part that prevents the drop temperature from dropping due to contact between the mold and the droplet, and also applies sufficient pressing force to the droplet at the center of the mold to improve the molding accuracy of the optical element. Thus, it is possible to provide an upper mold for forming a droplet, an optical element, and a method for manufacturing the optical element, which can reduce the thickness of the optical element.

  Note that the detailed configuration and detailed operation of each component constituting the upper mold for forming a droplet, the optical element, and the manufacturing method of the optical element according to the present invention are appropriately changed without departing from the spirit of the present invention. Is possible.

DESCRIPTION OF SYMBOLS 1 Upper mold | type 11 Optical surface part 13 Escape part 13c (Provided in the vicinity of the position facing the dripping position of the upper mold 1) Escape part 13p (Provided in the position away from the position facing the dripping position of the upper mold 1) Escape portion 13t Tapered portion 13b (of escape portion 13) Deepest portion 15 (of escape portion 13) 15 Opposing surface 2 Lower mold 21 Optical surface portion 23 Opposing surface 3 Droplet 31 (a lump of molding material) 31 Optical element 33 Excessive coverage Molding material

Claims (5)

A lower mold having a plurality of optical surface portions formed thereon and an upper mold having a plurality of optical surface portions formed thereon, press-molding a batch of material droplets dropped onto the lower mold, An upper mold for droplet forming to obtain an optical element,
Provided with an escape portion for allowing excess molding material to escape between the plurality of optical surface portions,
The upper part for forming a droplet, wherein the escape part has a depth or a volume so that an excessive molding material flowing in during press molding does not reach the deepest part of the escape part.   The depth or volume of the relief portion provided in the vicinity of the position facing the droplet dropping position of the batch of molding material is the depth or volume of the relief portion provided at a position away from the position facing the dropping position. The upper mold for forming a droplet according to claim 1, wherein the upper mold is larger than a depth or a volume.   The relief portion has a tapered portion on a side close to the surface facing the lower mold, and the tapered portion has a depth or volume such that the excessive material to be molded does not reach the deepest portion of the relief portion. The upper mold for forming a droplet according to claim 1 or 2, wherein the upper mold is used.   It was obtained by press-molding a batch of molding material droplets using a lower mold having a plurality of optical surface portions and an upper mold according to any one of claims 1 to 3. A featured optical element. A molding step of press-molding a batch of droplets of a molding material using the lower mold in which a plurality of optical surface portions are formed and the upper mold according to any one of claims 1 to 3,
An optical element manufacturing method comprising: an optical element separation step of separating the plurality of optical elements obtained in the molding step into individual optical elements.

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