WO2021006126A1 - Transmissive optical element manufacturing method - Google Patents

Transmissive optical element manufacturing method Download PDF

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Publication number
WO2021006126A1
WO2021006126A1 PCT/JP2020/025726 JP2020025726W WO2021006126A1 WO 2021006126 A1 WO2021006126 A1 WO 2021006126A1 JP 2020025726 W JP2020025726 W JP 2020025726W WO 2021006126 A1 WO2021006126 A1 WO 2021006126A1
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WO
WIPO (PCT)
Prior art keywords
optical element
thermoplastic resin
mold
manufacturing
resin film
Prior art date
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PCT/JP2020/025726
Other languages
French (fr)
Japanese (ja)
Inventor
荒井　邦仁
澤口　太一
伊藤　敬志
Original Assignee
日本ゼオン株式会社
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Application filed by 日本ゼオン株式会社 filed Critical 日本ゼオン株式会社
Priority to CN202080034663.9A priority Critical patent/CN113811433B/en
Priority to KR1020217042052A priority patent/KR20220032010A/en
Priority to JP2021530631A priority patent/JPWO2021006126A1/ja
Publication of WO2021006126A1 publication Critical patent/WO2021006126A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
    • B29C51/18—Thermoforming apparatus
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/00009—Production of simple or compound lenses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32—Component parts, details or accessories; Auxiliary operations
    • B29C43/34—Feeding the material to the mould or the compression means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32—Component parts, details or accessories; Auxiliary operations
    • B29C43/50—Removing moulded articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32—Component parts, details or accessories; Auxiliary operations
    • B29C43/58—Measuring, controlling or regulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
    • B29C51/26—Component parts, details or accessories; Auxiliary operations
    • B29C51/30—Moulds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
    • B29C51/26—Component parts, details or accessories; Auxiliary operations
    • B29C51/42—Heating or cooling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
    • B29C51/26—Component parts, details or accessories; Auxiliary operations
    • B29C51/44—Removing or ejecting moulded articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
    • B29C51/26—Component parts, details or accessories; Auxiliary operations
    • B29C51/46—Measuring, controlling or regulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/00009—Production of simple or compound lenses
    • B29D11/00432—Auxiliary operations, e.g. machines for filling the moulds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/00009—Production of simple or compound lenses
    • B29D11/0048—Moulds for lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2011/00—Optical elements, e.g. lenses, prisms

Definitions

  • the present invention relates to a method for manufacturing a transmissive optical element. More specifically, the present invention relates to a method for manufacturing a transmissive optical element using a resin film.
  • transmissive optical elements such as lenses used in camera units and the like have generally been manufactured by an injection molding method.
  • a lens is formed by an injection molding method, it is difficult to completely suppress the formation of weld lines in the obtained lens.
  • birefringence was likely to occur in the lens obtained according to the injection molding method. For this reason, it is difficult to sufficiently increase the ratio of the region capable of exhibiting sufficiently high optical performance in the obtained lens, and a lens having a small diameter of less than 1 cm is injected by an injection molding method. Even if it was formed according to the above, it was difficult to make it function sufficiently as a lens.
  • Patent Document 1 discloses a method for manufacturing an optical lens in which a resin sheet is vacuum-compressed in a mold.
  • the thickness of the resin sheet, the depth of the deepest part of the mold, the glass transition temperature of the resin sheet, and the surface temperature of the mold at the time of molding are molded under conditions that satisfy a specific relationship. It is possible to efficiently manufacture an optical lens having low birefringence and high shape accuracy.
  • an object of the present invention is to provide a method for manufacturing a transmission type optical element capable of efficiently manufacturing a transmission type optical element having low birefringence and high shape accuracy.
  • the present inventors have conducted diligent studies in order to achieve the above object. As a result, when the resin film is formed by press molding using a mold, the present inventors use a flat plate mold as the mold and apply tension to the resin film at a specific timing in the manufacturing process. As a result, we have newly found that it is possible to efficiently manufacture a transmission type optical element having low birefringence and high shape accuracy, and completed the present invention.
  • the present invention aims to advantageously solve the above problems, and the method for manufacturing a transmissive optical element of the present invention is a method for manufacturing a transmissive optical element using a thermoplastic resin film.
  • Tg glass transition temperature
  • thermoplastic resin film containing a plurality of transmissive optical elements by releasing the heat press film while applying tension.
  • a transmissive optical element with low birefringence and high shape accuracy by releasing the thermoplastic resin film that has been heat-pressed using a pair of flat plate dies while applying tension when the thermoplastic resin film is released after cooling. Can be efficiently manufactured.
  • Glass transition temperature of the thermoplastic resin film (Tg r) ° C.” can be measured based on JIS K7121.
  • the method for manufacturing a transmissive optical element of the present invention further includes a transport step of transporting the thermoplastic resin film along a predetermined transport direction prior to the heat pressing step, and in the mold release step.
  • the mold is released while applying tension along the transport direction, and the magnitude of the tension is 1 N or more and 2000 N or less per 1 m of the width of the thermoplastic resin film in the direction orthogonal to the transport direction. Is preferable.
  • the "magnitude of tension" can be controlled by the method described in the examples.
  • At least one of the pair of flat plate molds has a plurality of optical surface forming regions having a diameter of 1 mm or more and 15 mm or less, and the plurality of optical surface forming regions.
  • the total depth of the optical surface forming region and the outermost portion forming region of the pair of flat plate molds is 500 ⁇ m, which includes the outer peripheral portion forming region which is a region adjacent to each outer peripheral portion of the above. The following is preferable.
  • At least one of the pair of flat plate dies includes a plurality of optical surface forming regions discretely arranged in the plane direction of the flat plate dies.
  • the minimum distance between the plurality of optical surface forming regions is preferably 1.0 mm or more.
  • a transmission type optical element of the present invention preferably has a glass transition temperature of the thermoplastic resin film (Tg r) is less than 200 ° C. 100 ° C. or higher.
  • Tg r thermoplastic resin film
  • the heat the in the press process temperature of the pair of flat plate mold (Tg r +30) °C or higher (Tg r +70) °C or less.
  • the mold cooling step it is preferable to cool the pair of flat dies to (Tg r -15) °C or lower.
  • thermoplastic resin film contains an alicyclic structure-containing resin. If the thermoplastic resin film contains an alicyclic structure-containing resin, a transmissive optical element having excellent transparency can be manufactured.
  • At least one of the pair of flat plate dies has an optical surface forming region having a number density of 0.16 pieces / cm 2 or more.
  • both of the pair of flat plate molds have a plurality of optical surface forming regions.
  • the method for manufacturing a transmission type optical element of the present invention includes a transmission type optical element separation step of separating the plurality of transmission type optical elements from the molded film obtained through the mold release step.
  • FIG. 1 shows the schematic structure of the transmission type optical element manufacturing apparatus which can be used for carrying out the manufacturing method of the transmission type optical element which concerns on one example of this invention. It is a schematic diagram for demonstrating one of the manufacturing examples of the optical lens which is a transmission type optical element which concerns on one example of this invention. It is a schematic diagram for demonstrating the case of manufacturing the optical lens which has a shape different from the shape shown in FIG.
  • a transmissive optical element such as an optical lens and a prism
  • the "optical lens” means a transparent body that exhibits a refracting action of light.
  • the “prism” means a transparent polyhedron exhibiting a light dispersion action, a refraction action, a total reflection action, and / or a birefringence action.
  • a plano-convex lens, a biconvex lens, a convex meniscus lens, a plano-concave lens, a biconcave lens, and a concave meniscus lens, one side and / or both sides are curved points. It is possible to suitably manufacture lenses having various shapes such as an aspherical lens having a lens. Further, according to the method for manufacturing a transmissive optical element of the present invention, various transmissive optical elements having a relatively small diameter can be manufactured with high shape accuracy, and therefore, for example, it is suitable as a lens for a camera unit of a small electronic / electrical device. It is possible to efficiently manufacture an optical lens that can be used in the above.
  • the method for manufacturing a transmissive optical element of the present invention is a method for manufacturing a transmissive optical element using a thermoplastic resin film.
  • the method for manufacturing a transmissive optical element of the present invention includes a "heat pressing step" in which a thermoplastic resin film is hot-pressed with at least a pair of flat plate dies to obtain a hot-pressed film, and the pair of flat-plate dies Upon cooling to the glass transition temperature (Tg r) ° C.
  • the hot press film is released from the mold while applying tension to obtain a molded film containing a plurality of transmissive optical elements, which is characterized by including a "mold release step".
  • the mold is released while applying tension to efficiently produce a transmissive optical element with low birefringence and high shape accuracy. It becomes possible to manufacture the product.
  • the method for manufacturing a transmissive optical element of the present invention may include a transport step of transporting the thermoplastic resin film along a predetermined transport direction prior to the heat pressing step. Furthermore, the method for manufacturing a transmission type optical element of the present invention may include a transmission type optical element separation step of separating a plurality of transmission type optical elements from a molding film after the mold release step.
  • the atmospheric pressure in the environment in which each step is carried out is not particularly limited, and may be within the standard state specified in JISZ 8703.
  • the following steps can be carried out by any means without particular limitation, but it is preferably carried out by using a so-called roll-to-roll manufacturing means. This is because the manufacturing efficiency of the transmissive optical element can be improved by carrying out each step described below using the roll-to-roll manufacturing means.
  • thermoplastic resin film is conveyed to a position where the heat press is performed along a predetermined transfer direction.
  • the transport direction is preferably a direction along a longitudinal direction orthogonal to the width direction of the thermoplastic film.
  • the thermoplastic resin film is hot pressed with at least a pair of flat plate dies to obtain a hot pressing film.
  • the heat pressing step is not particularly limited as long as at least a pair of flat plate dies are used, and the thermoplastic resin film may be hot pressed using a pair of flat plate dies, or a plurality of pairs of flat plate dies may be used. Different parts of one thermoplastic resin film may be heat-pressed simultaneously or at different times depending on the mold.
  • the method for manufacturing a transmissive optical element of the present invention the occurrence of birefringence in the obtained transmissive optical element is suppressed by subjecting the thermoplastic resin film to a hot press using a flat plate die regardless of the injection molding method. can do.
  • thermoplastic resin film is not particularly limited as long as it is thermoplastic, and a film formed by using any known thermoplastic resin can be used.
  • the "film” means an object having a shape in which the front surface and the back surface (that is, the main surface) face each other with a distance corresponding to the thickness.
  • thermoplastic resin that can constitute the thermoplastic resin film include (meth) acrylic resin, alicyclic structure-containing resin, styrene resin, polycarbonate resin, polyester resin, polyether resin, urethane resin, and thiourethane resin. Can be mentioned.
  • (meth) acrylic refers to acrylic and / or methacrylic.
  • thermoplastic resin film contains an alicyclic structure-containing resin because a transmissive optical element having excellent transparency can be obtained.
  • the alicyclic structure-containing resin is a polymer having an alicyclic structure such as a saturated cyclic hydrocarbon structure and an unsaturated cyclic hydrocarbon structure in the main chain and / or the side chain. Among them, those having a cycloalkane structure in the main chain are preferable because it is easy to obtain a transmission type optical element having excellent mechanical strength and heat resistance.
  • the proportion of repeating units having an alicyclic structure in the polymer constituting the alicyclic structure-containing resin (hereinafter, also referred to as “alicyclic structure-containing polymer”) is not particularly limited, but all contained in the polymer.
  • the repeating unit 50% by mass or more is preferable, 70% by mass or more is more preferable, and 90% by mass or more is further preferable.
  • an alicyclic structure-containing polymer having an alicyclic structure and a ratio of repeating units of 50% by mass or more it becomes easy to obtain a transmissive optical element having excellent transparency and heat resistance.
  • the alicyclic structure-containing polymer examples include a norbornene-based polymer, a monocyclic cyclic olefin-based polymer, a cyclic conjugated diene-based polymer, and a vinyl alicyclic hydrocarbon-based polymer.
  • norbornene-based polymers are preferable from the viewpoint of enhancing the transparency, heat resistance, and mechanical strength of the obtained transmissive optical element.
  • these polymers mean not only the polymerization reaction product but also the hydride thereof.
  • the norbornene-based polymer is a polymer of norbornene-based monomers or a hydride thereof.
  • Examples of the norbornene-based polymer include a ring-opening polymer of a norbornene-based monomer, a ring-opening polymer of a norbornene-based monomer and another monomer capable of ring-opening copolymerization, an addition polymer of a norbornene-based monomer, and a norbornene-based monomer. Examples thereof include addition polymers with other monomers copolymerizable with this, and hydrides of these polymers.
  • a ring-opening polymer hydride of a norbornene-based monomer that is, a norbornene-based ring-opening polymer hydride
  • a thermoplastic resin film formed by using a norbornene-based ring-opening polymer hydride the transparency, heat resistance, mechanical strength, etc. of the obtained transmissive optical element can be further improved, and the transmissivity can be further improved. It is possible to improve the releasability and transferability when manufacturing a mold optical element.
  • norbornene-based monomer bicyclo [2.2.1] hept-2-ene (common name: norbornene) and derivatives thereof, tricyclo [4.3.0 1,6. 1 2,5 ] Deca-3,7-diene (trivial name dicyclopentadiene) and its derivatives, 7,8-benzotricyclo [4.3.0.1 2,5 ] deca-3-ene (trivial name)
  • Metanotetrahydrofluorene 1,4-methano-1,4,4a, 9a-also referred to as tetrahydrofluorene) and its derivatives, tetracyclo [4.4.0.1 2,5 .
  • Dodeca-3-ene (common name: tetracyclododecene) and its derivatives, and the like.
  • substituent that can be contained in the derivative include an alkyl group, an alkylene group, a vinyl group, an alkoxycarbonyl group, and an alkylidene group.
  • a derivative as a norbornene-based monomer 8-methoxycarbonyl-tetracyclo [4.4.0.1 2,5 . 1 7, 10 ]
  • Dodeca-3-ene 8-methyl-8-methoxycarbonyl-tetracyclo [4.4.0.1 2,5 .
  • These norbornene-based monomers can be used alone or in combination of two or more.
  • Examples of other monomers that can be open-ring copolymerized with the norbornene-based monomer include monocyclic cyclic olefin-based monomers such as cyclohexene, cycloheptene, and cyclooctene.
  • Other monomers that can be additionally copolymerized with norbornene-based monomers include ⁇ -olefins having 2 to 20 carbon atoms such as ethylene, propylene, 1-butene, 1-pentene, and 1-hexene, and derivatives thereof; cyclobutene and cyclopentene.
  • Cyclohexene, cyclooctene, and cycloolefins such as 3a, 5,6,7a-tetrahydro-4,7-methano-1H-indene and derivatives thereof; 1,4-hexadiene, 4-methyl-1,4-hexadiene. , 5-Methyl-1,4-hexadiene, and non-conjugated diene such as 1,7-octadiene; and the like.
  • the ring-opening polymer and the addition polymer containing the norbornene-based monomer as described above can be synthesized by polymerizing in the presence of a known catalyst. Further, these hydrides can be obtained by a hydrogenation reaction using a known hydrogenation catalyst.
  • Examples of the monocyclic cyclic olefin polymer, the cyclic conjugated diene polymer, and the vinyl alicyclic hydrocarbon polymer include those described in International Publication No. 2017/126599.
  • a commercially available product can also be used as the alicyclic structure-containing polymer.
  • Commercially available products include Zeon Corporation, ZEONEX (registered trademark), Mitsui Chemicals, APEL (registered trademark), JSR, ARTON (registered trademark), Polyplastics (registered trademark), etc. Can be mentioned.
  • the thermoplastic resin film may contain a component other than the resin component as described above.
  • components other than the resin component include additives such as light stabilizers, ultraviolet absorbers, antioxidants, mold release agents, antistatic agents, carbon materials (carbon and the like), pigments, and dyes.
  • the blending amount of these components is not particularly limited and can be appropriately determined.
  • the total amount of these additives may be, for example, 20% by mass or less, preferably 10% by mass or less, assuming that the resin component is 100% by mass.
  • the method for producing the thermoplastic resin film is not particularly limited, and a conventionally known appropriate method can be adopted.
  • a predetermined component is mixed to obtain a molding material for manufacturing a thermoplastic resin film, and the thermoplastic resin film is obtained by a melt extrusion molding method, a melt casting method, an injection molding method, or the like. Can be done.
  • the glass transition temperature of the thermoplastic resin film (Tg r) is not particularly limited, preferably at least 100 ° C., more preferably at least 120 ° C., preferably 200 ° C. or less, more preferably 160 ° C. or less. If the glass transition temperature of the thermoplastic resin film (Tg r) is less than the above lower limit, it is possible to further improve the shape accuracy of the transmission-type optical element obtained. The glass transition temperature of the thermoplastic resin film (Tg r) is not more than the above upper limit, to increase the production efficiency of the transmission type optical element, it is possible to increase the shape accuracy even.
  • the thickness of the thermoplastic resin film may vary even within a single film.
  • the thickness variation of the thermoplastic resin film is preferably 10 ⁇ m or less, and more preferably 5 ⁇ m or less.
  • the thickness variation is 0 ⁇ m, but in general, the thickness variation can be 0.5 ⁇ m or more.
  • the thickness variation of the thermoplastic resin film is the difference between the maximum thickness and the minimum thickness of the thermoplastic resin film, and can be measured according to the method described in Examples.
  • the thickness of the thermoplastic resin film can be appropriately selected according to the diameter of the transmissive optical element to be manufactured.
  • the thickness of the thermoplastic resin film is usually 50 ⁇ m or more, preferably 70 ⁇ m or more, usually 500 ⁇ m or less, and preferably 400 ⁇ m or less.
  • the thickness of the thermoplastic resin film corresponds to the simple arithmetic mean value of the thicknesses at a plurality of randomly selected measurement points as described in the examples. ..
  • the pair of flat plate molds used in the method for manufacturing a transmissive optical element of the present invention is not particularly limited as long as at least one of them has a plurality of recesses which are optical surface forming regions, and may have any shape. ..
  • the plurality of optical surface forming regions are discretely arranged in the plane direction of the flat plate mold. It is preferable that the plurality of optical surface forming regions are arranged at equal intervals in the plane direction of the flat plate mold.
  • the transmissive optical element formed according to the method for manufacturing a transmissive optical element of the present invention is adjacent to at least one optical surface such as a concave surface, a convex surface, or an aspherical surface having an inflection point, and the optical surface. It may have an outer peripheral portion (flange portion) which is a region to function as a mounting region or the like for a holding member for holding the transmissive optical element. The outer peripheral portion may be perpendicular to or substantially perpendicular to the optical axis of the transmissive optical element.
  • the "optical axis of the transmissive optical element" corresponds to an axis that passes through the center of the transmissive optical element and is perpendicular to the optical surface.
  • the flat plate mold for forming a transmissive optical element having an optical surface and an outer peripheral portion has a plurality of optical surface forming regions and an outer circumference which is a region adjacent to each outer periphery of the plurality of optical surface forming regions. It includes a part-forming region. At least a part of the outer peripheral portion forming region may be a horizontal region parallel to the plane direction of the flat plate mold. Further, the flat plate mold is optionally used to form a region adjacent to the outer peripheral portion and not included in the transmissive optical element separated by the transmissive optical element separation step described later. It may have a peripheral edge portion (margin portion).
  • Both of the pair of flat plate molds may have a plurality of optical surface forming regions. This is because a transmissive optical element having both sides shaped can be efficiently manufactured by molding using a pair of flat plate dies each having an optical surface forming region.
  • the shapes of the pair of flat plate molds may be the same or different depending on the shape of the transmission type optical element to be manufactured.
  • the number density of the optical surface forming region in at least one of the pair of flat plate molds is preferably 0.16 pieces / cm 2 or more, and is 0. More preferably, it is .32 pieces / cm 2 or more.
  • the number density is 0.16 / cm 2
  • the number density is 0.32 / cm 2.
  • the transmissive optical element when a transmissive optical element is manufactured using a flat plate die of about A4 size in which the number density of the optical surface forming region is equal to or higher than the above lower limit value, one cycle including one heat pressing step is performed. By performing the treatment, 100 or more transmissive optical elements can be obtained, so that the manufacturing efficiency of the transmissive optical elements can be further improved.
  • the upper limit of the number density of the optical surface forming region in at least one of the pair of flat plate molds is not particularly limited.
  • the number density may be such that the number of transmissive optical elements that can be manufactured per cycle is 2000 or less.
  • the diameter of the plurality of optical surface forming regions provided on at least one of the pair of flat plate molds is preferably 1 mm or more and 15 mm or less.
  • a sufficient amount of light can be transmitted by the obtained transmissive optical element. Therefore, for example, when an optical lens is manufactured as a transmissive optical element, the lens diameter of the obtained optical lens is sufficiently large, and a light receiving element such as a sensor provided on the rear side of the optical system including the optical lens. It is possible to reach a sufficient amount of light rays. Further, the transmissive optical element having a diameter of 15 mm or less is not too large and has an appropriate size for being attached to a camera unit or the like.
  • the diameter of the optical surface forming region is the diameter of the opening of the optical surface forming region, which is a recess provided in the flat plate mold. That is, the diameter of the optical surface forming region corresponds to the largest diameter when the recess is viewed in the depth direction.
  • the transmissive optical element can be formed with high shape accuracy, so that the diameter of the optical surface forming region of the flat plate mold can be substantially obtained. It can correspond to the diameter of the optical surface of the transmissive optical element.
  • the minimum distance between the plurality of optical surface forming regions provided on at least one of the pair of flat plate molds is preferably 1.0 mm or more, more preferably 3.0 mm or more, and preferably 50 mm or less.
  • each transmission type optical element is efficiently separated from the molded film in the transmission type optical element separation step described later. It is possible to improve the manufacturing efficiency of the transmissive optical element.
  • the minimum distance between the plurality of optical surface forming regions is not more than the above upper limit value, the number density of the transmission type optical elements in the molded film obtained through one heat pressing step can be sufficiently increased. The manufacturing efficiency of the transmissive optical element can be further improved.
  • the plurality of optical surface forming regions are arranged at equal intervals in the plane direction of the flat plate mold.
  • the total depth of the shallowest portion in the optical surface forming region and the outer peripheral portion forming region of the pair of flat plate molds is preferably 500 ⁇ m or less, more preferably 400 ⁇ m or less, further preferably 300 ⁇ m or less, and preferably 50 ⁇ m or more.
  • the total depth of the shallowest portions in the optical surface forming region and the outer peripheral portion forming region of the pair of flat plate molds (D min in FIGS. 2 and 3 described later) is the thinnest in the obtained transmission type optical element.
  • D min is shown as being located in the outer peripheral portion forming region of the pair of flat plate molds, respectively.
  • the target transmission type optical element is a biconcave lens
  • the thickness of the thinnest portion of the optical surface forming region is thinner than the thickness of the outer peripheral portion forming region.
  • D min is located in the optical surface forming region of the pair of flat plate molds.
  • the stress is locally applied when an external force is applied to the obtained transmissive optical element.
  • the mechanical strength of the transmissive optical element can be increased by suppressing the concentration of the stress.
  • the strength of the molded film is ensured, and cracks or the like occur in the molded film at an unexpected timing such as during transportation. This can be suppressed and the manufacturing efficiency of the transmissive optical element can be improved.
  • the “total depth of the shallowest portion in the outer peripheral portion forming region of the flat plate mold” is the mold in the outer peripheral portion forming region when a pair of flat plate dies are arranged or brought into contact with each other at the time of molding. Corresponds to the shortest distance between molds.
  • the total depth (D max ) of the deepest portion in the optical surface forming region of the pair of flat plate molds corresponds to the thickness of the thickest portion in the obtained transmissive optical element.
  • the “total depth of the deepest portion in the optical surface forming region of the flat plate mold” is the optical surface forming region when a pair of flat plate molds are opposed to each other for molding and arranged or brought into contact with each other. Corresponds to the maximum distance between molds.
  • the total depth of the deepest portion in the optical surface forming region of the pair of flat plate molds is larger than the total depth of the shallowest portion, and can be, for example, more than 50 ⁇ m and 1000 ⁇ m or less.
  • the thickness T f of the thermoplastic resin film (the value of the simple arithmetic mean of the thicknesses at 100 or more measurement points randomly selected) is formed on the outer periphery of the pair of flat plate molds. It is preferable that the total depth of the shallowest portion in the region (D min ) or more and the total depth of the deepest portion in the optical surface forming region (D max ) or less. More preferably, the thickness T f of the thermoplastic resin film satisfies (D min ⁇ 1.1) ⁇ T f ⁇ (D max ⁇ 0.9).
  • the thickness T f of the thermoplastic resin film is not more than the above upper limit value, the thickness of the thinnest portion of the transmissive optical element can be efficiently thinned to a desired thickness. Further, when the thickness T f of the thermoplastic resin film is at least the above lower limit value, the thermoplastic resin can be satisfactorily filled in the optical surface forming region in the pair of flat plate molds, so that the obtained transmission can be obtained. The shape accuracy of the mold optical element can be further improved.
  • the temperature of the pair of flat plate dies in the hot pressing step is preferably (Tg r +30) ° C. or higher, more preferably (Tg r +40) ° C. or higher, preferably (Tg r +70) ° C. or lower, and (Tg r +60) ° C.
  • the following is more preferable.
  • the temperature of the pair of flat plate dies in the heat pressing step is equal to or higher than the above lower limit value, the occurrence of birefringence in the obtained transmission type optical element can be suppressed more satisfactorily.
  • the transmission type optical element can be manufactured more efficiently.
  • a predetermined press pressure is applied to the flat plate dies to press the thermoplastic resin film.
  • a mold heating step including heating the thermoplastic resin film in a state of being sandwiched between the flat plate molds between the heat pressing step and the above-mentioned transporting step.
  • the press pressure in the mold heating step is preferably lower than the press pressure in the hot press step. More specifically, for example, when the press pressure in the hot pressing step is 1 MPa or more and 10 MPa or less, the press pressure in the die heating step can be less than 1 MPa.
  • the mold heating step starts at the time when the thermoplastic resin film and one of the pair of flat plate dies come into contact with each other, and ends at the time when the press pressure is switched to the press pressure in the hot press step.
  • the heat input to the flat plate die is started at a desired timing in the mold heating step, and the temperature is gradually raised to the above-mentioned "temperature of a pair of flat plate dies in the hot pressing step".
  • the temperature rise may be completed at a timing before the end point of the mold heating step (for example, 50 seconds before the end time of the mold heating step).
  • the mold temperature is not particularly limited and can be appropriately adjusted according to a known general method (for example, a temperature control method using a known heater and cooler).
  • the material used for the mold a known material can be used.
  • carbon steel, stainless steel, and alloys based on these are mentioned.
  • stainless steel such as STAVAX (registered trademark) material (manufactured by Uddeholm) is preferable from the viewpoint of workability and hardness.
  • STAVAX registered trademark
  • metals such as chromium, titanium, and nickel.
  • electroless nickel-phosphorus plating is the mold. It is more preferable to use a mold formed on the surface.
  • the pressing pressure and pressing time in the hot pressing step are not particularly limited, and are appropriately determined according to the type and size of the thermoplastic resin film to be used, the shape and size of the target transmissive optical element, and the like. Can be done.
  • the press pressure can be 1 MPa or more and 10 MPa or less, and the press time can be 10 seconds or more and 100 seconds or less.
  • the press pressure in the die heating step can be, for example, less than 1 MPa.
  • the time required from the start point to the end point of the mold heating step can be 10 seconds or more and 100 seconds or less.
  • the mold cooling process to cool a pair of flat molds to the glass transition temperature (Tg r) ° C. below the temperature of the thermoplastic resin film, cooling the hot pressed film.
  • the starting point of the mold cooling process is, for example, the time when the temperature control for cooling the flat plate mold is started for the flat plate mold after a predetermined time has elapsed from the start time of the hot pressing process, or the start of the hot pressing process. It may be the time when the heat input to the flat plate mold is stopped after a predetermined time has elapsed from the time point.
  • the end point of the mold cooling step may be a time when the mold temperature is lowered to the mold cooling temperature described later, or a time when a predetermined time (for example, 50 seconds) has elapsed from such a time.
  • Mold cooling temperature must be at the glass transition temperature (Tg r) ° C. or less of the thermoplastic resin film, (Tg r -15) ° C. or less are preferred, (Tg r -30) ° C. and more preferably less, ( Tg r- 40) ° C. or lower is more preferable. Further, the mold cooling temperature is preferably (Tg r -80) is ° C. or higher, and more preferably (Tg r -75) °C or higher. When the mold cooling temperature is not more than the above upper limit value, it is easy to release the mold in the mold release step described later, and the shape accuracy of the obtained transmissive optical element can be effectively improved. Further, when the mold cooling temperature is equal to or higher than the above lower limit value, the manufacturing efficiency of the transmission type optical element can be further improved.
  • the mold cooling time, the mold cooling rate, etc. are not particularly limited, and may be appropriately determined according to the type and size of the thermoplastic resin film, the shape and size of the target transmissive optical element, and the like. it can.
  • the mold cooling time can be 10 seconds or more and 100 seconds or less
  • the mold cooling rate can be 50 ° C./min or more and 300 ° C./min or less.
  • ⁇ Release process> In the mold release step, after the mold cooling step, when the hot press film is released from the pair of flat plate molds, the hot press film is released while applying tension to include a plurality of transmissive optical elements. Obtain a molded film. "When releasing from a pair of flat plate molds" means a time when the mold cooling process is completed and the pair of flat plate molds are started to be opened. At this point, by putting tension on the heat-pressed film, it is possible to suppress distortion of the transmissive optical element at the time of mold release and improve the shape accuracy of the obtained transmissive optical element. it can. Here, it is preferable that the tension acts as a force in the direction along the transport direction.
  • the method of controlling the tension in the mold release step is not particularly limited, and the tension can be controlled by a known method.
  • it can be controlled by a winding roll of the hot press film, a winding roll for winding the hot press film, a nip roll separately provided for tension control, or the like.
  • An exemplary configuration of a roll-to-roll manufacturing apparatus including a take-up roll and a take-up roll will be described later with reference to FIG.
  • not only in the mold removing step, but also in the above-mentioned heat pressing step from the die heating step in which the thermoplastic resin film and one of the pair of flat plate dies come into contact with each other until the time when the mold removing step is started.
  • thermoplastic resin film is continuously or intermittently tensioned in the step. This is because the shape accuracy of the obtained transmissive optical element can be further improved.
  • tension may be applied to the thermoplastic resin film in other steps other than the above period. That is, tension may be applied to the thermoplastic resin film through all the steps from the transfer step to the step that can be performed after the mold release step.
  • the magnitude of the tension applied to the hot press film in the transport direction is preferably 1 N or more, more preferably 10 N or more, and more preferably 2000 N or less per 1 m of the width of the thermoplastic resin film. It is preferably 1000 N or less, and more preferably 1000 N or less.
  • the "width of the thermoplastic resin film" is a direction orthogonal to the transport direction.
  • Transmission type optical element separation process a plurality of transmission type optical elements are separated from the molded film obtained through the mold release step.
  • the transmission type optical element separation step By carrying out the transmission type optical element separation step of separating a plurality of transmission type optical elements from the molded film, the transmission type optical element can be manufactured more efficiently.
  • the separation method is not particularly limited, and each transmissive optical element can be separated from the molded film by any known method such as punching with a punching die.
  • the transmission optical element separation step may be carried out on the same production line as the steps up to the previous step, that is, in-line. Alternatively, the transmission type optical element separation step may be carried out on a production line different from the steps up to the previous step, that is, offline.
  • FIG. 1 is a diagram showing a schematic structure of a transmission type optical element manufacturing apparatus that can be used to carry out the method for manufacturing a transmission type optical element according to an example of the present invention.
  • the transmission type optical element manufacturing apparatus 100 supports an upper mold 1A, a lower mold 1B, and an upper mold 1A constituting a pair of flat plate molds, and heats and cools the upper mold 2A and an upper temperature control device 2A.
  • a z-axis direction moving table 3 that supports the device 2A and is configured to be movable in the z-axis direction, a lower temperature control device 2B that supports the lower mold 1B and heats and cools the lower mold 1B, and a lower temperature control device 2B.
  • the transmission type optical element manufacturing apparatus 100 may include a take-up roll 5A which is a constituent part for delivering the thermoplastic resin film 7 and a take-up roll 5B which is a constituent part for winding the molded film. Furthermore, the transmission type optical element manufacturing apparatus 100 may include a feed roll 6 as a component for controlling the feed mode of the thermoplastic resin film 7. It should be noted that these various components are not limited to the illustrated mode, and can be replaced by any existing concrete means as long as they can exhibit the above-mentioned functions. In FIG. 1, the vertical direction of the transmission type optical element manufacturing apparatus 100 is the z-axis, and the press surface of the transmission type optical element manufacturing apparatus 100 is the xy plane. Further, the transmission type optical element manufacturing apparatus 100 shown in FIG. 1 is an apparatus for molding a transmission type optical element from a resin film by a so-called "roll-to-roll" method.
  • the transfer step (S01), the die heating step, the hot pressing step (S02), the die cooling step (S03), and the release step will be described as being carried out using the transmission type optical element manufacturing apparatus 100 shown in FIG.
  • the above-mentioned ⁇ transmission type optical element separation step> can be carried out by providing a punching unit or the like (not shown) in the transmission type optical element manufacturing apparatus 100.
  • thermoplastic resin film 7 is set on the unwinding roll 5A, the winding roll 5B, and the feed roll 6 of the transmissive optical element manufacturing apparatus 100. To do. Then, in the transfer step (S01), the thermoplastic resin film 7 is conveyed along a predetermined transfer direction prior to the die heating step and the heat pressing step (S02). In FIG. 1, the transport direction is the direction indicated by the arrow 10.
  • thermoplastic resin film 7 is hot pressed by the upper die 1A and the lower die 1B.
  • the position of the thermoplastic resin film 7 in the z-axis direction can also be appropriately adjusted during the heat pressing step or the like.
  • the start time of the die heating step that is, the upper die 1A and the lower die 1B After the time when at least one of them comes into contact with the thermoplastic resin film 7, by the time when the hot pressing step (S02) is started (when the application of a predetermined pressing pressure is started), the upper dies 1A and the lower dies 1B
  • the temperature is set to the above-mentioned predetermined temperature range by the upper temperature control device 2A and the lower temperature control device 2B.
  • the temperature of the upper mold 1A and a lower mold 1B Per the mold cooling step (S03), by the upper temperature adjusting unit 2A and the lower temperature adjusting apparatus 2B, the temperature of the upper mold 1A and a lower mold 1B, the glass transition temperature of the thermoplastic resin film 7 (Tg r) °C or less It is preferable to set the temperature to.
  • thermoplastic resin film 7 is released from the flat plate mold while applying tension to the thermoplastic resin film 7 as the hot press film.
  • the tension can be loaded and adjusted using, for example, a take-up roll 5A, a take-up roll 5B, and a feed roll 6.
  • FIGS. 2 and 3 Outline of manufacturing example of transmissive optical element
  • FIGS. 2 and 3 The configuration with the same reference numerals as those in FIG. 1 is as described in relation to FIG.
  • the shapes of the flat plate molds are different. Therefore, in FIG. 2, it is shown as an upper mold 1A'and a lower mold 1B', and in FIG. 3, it is shown as an upper mold 1A "and a lower mold 1B". Further, since the shapes of the obtained optical lenses are also different, the obtained optical lens is shown as an optical lens 8'in FIG.
  • FIG. 2 and 3 are cross-sectional views seen from the transport direction, and are a thermoplastic resin film 7, an upper mold 1A'and a lower mold 1B', an upper mold 1A "and a lower mold 1B", and , Optical lenses 8'and 8 "show only a part, respectively.
  • thermoplastic resin film 7 transported through a transport step (S01) is subjected to a heat pressing step (S02) to form an upper die 1A'and a lower die as a pair of flat plate dies.
  • the thermoplastic resin film 7 is melted or deformed by heat by hot pressing with the mold 1B', and the thermoplastic resin is filled in the flat plate die.
  • the upper mold 1A'and the lower mold 1B' are in contact with each other in a portion (not shown) in the mold heating step and the heat pressing step (S02).
  • the thickness of the thinnest portion of the thermoplastic resin film 7 becomes D min .
  • the upper mold 1A'and the lower mold 1B' are cooled in the mold cooling step (S03). Further, in the mold release step (S04), the thermoplastic resin film 7 as a molding film is released from the upper mold 1A'and the lower mold 1B'. Then, in the transmission type optical element separation step (S05), the thermoplastic resin film 7 as a molding film is cut along the cutting line indicated by the broken line to obtain a plurality of optical lenses 8'.
  • the optical lens as a transmissive optical element obtained by the method for manufacturing a transmissive optical element of the present invention has low birefringence and high shape accuracy.
  • the optical lens as a transmissive optical element obtained by the method for manufacturing a transmissive optical element of the present invention preferably has a phase difference within the optical effective diameter of 100 nm or less, more preferably 50 nm or less. , 20 nm or less is more preferable.
  • An optical lens having a phase difference of 100 nm in an optically effective system is an optical lens having sufficiently low birefringence.
  • the value of the phase difference can be obtained according to the method described in Examples.
  • the transmissive optical element obtained by the method for manufacturing a transmissive optical element of the present invention has a maximum error in the optical surface shape of the manufactured transmissive optical element, that is, PV when the shape of the optical surface in design is used as a reference.
  • the (Peek to Valley) value is preferably 1.0 ⁇ m or less, more preferably 0.6 ⁇ m or less, and further preferably 0.4 ⁇ m or less.
  • a transmissive optical element having a PV value of 1.0 ⁇ m or less is a transmissive optical element having sufficiently high shape accuracy.
  • the present invention will be described in more detail with reference to Examples and Comparative Examples.
  • the present invention is not limited to these examples.
  • the thickness, thickness variation, and glass transition temperature of the thermoplastic resin film were measured as follows.
  • the manufacturing efficiency considering the shape accuracy average value, the shape accuracy variation, the phase difference, and the shape non-defective rate, and the manufacturing efficiency considering the shape and low birefringence are as follows. Calculated and evaluated.
  • the unwinding roll and winding provided in the manufacturing apparatus according to the schematic configuration shown in FIG. The roll etc. were controlled by the tension controller. Table 1 shows the control values.
  • the tension values shown in Table 1 are values per 1 m of width of the thermoplastic resin film.
  • the direction of tension was set along the transport direction.
  • an optical lens biconvex lens or convex meniscus lens
  • thermoplastic resin film Three sheets were cut out to a length of 250 mm at arbitrary points of the thermoplastic resin film, and the thickness was measured at 11 ⁇ 11 points at intervals of 20 mm at the center of each of the cut out samples in the longitudinal direction and the width direction, and the thermoplastic resin film was formed. The maximum thickness and the minimum thickness of were obtained. The thickness of the thermoplastic resin film was taken as the average value of these. Further, the thickness variation of the thermoplastic resin film was defined as the difference between the maximum thickness and the minimum thickness.
  • thermoplastic resin film ⁇ Glass transition temperature of thermoplastic resin film>
  • the glass transition temperature (Tg) of the thermoplastic resin film used in Examples and Comparative Examples was measured at a heating rate of 10 ° C. based on JIS K7121 using a differential scanning calorimeter (“DSC6220” manufactured by SII Nanotechnology). It was measured under the condition of / minute.
  • the shape accuracy of the optical lens which is the measurement sample obtained in the examples and comparative examples, is measured using a shape measuring instrument (manufactured by Mitaka Kohki Co., Ltd., "NH-3SP") with the designed optical surface as the reference surface. It was measured as a PV value.
  • the simple average value of the measured PV values was defined as the shape accuracy average value, and the standard deviation was defined as the shape accuracy variation.
  • PV values were measured for each of the 396 optical lenses obtained in the same heat pressing step as the optical lenses as measurement samples. Further, in Comparative Example 3, the PV value was measured for each of the 414 optical lenses, which are molded products for one round of the embossed roll.
  • phase difference within the effective diameter of the optical lens as the measurement sample was measured using a resin molded lens inspection system [“WPA-100”, manufactured by Photonics Lattice).
  • the phase difference value is obtained as a value standardized at the measurement wavelength (543 nm).
  • the value of the phase difference was a simple average value of the values obtained by measuring a plurality of measurement samples.
  • the obtained phase difference values were evaluated according to the following criteria. The smaller the phase difference value, the smaller the birefringence.
  • C 50 nm or more and 100 nm or less
  • D 100 nm or less
  • the direction perpendicular to the width direction of the thermoplastic film is the longitudinal direction, and has a sufficient length for molding by the roll-to-roll molding method.
  • the thermoplastic resin film obtained according to the above was set in a manufacturing apparatus according to the schematic configuration shown in FIG.
  • the pair of flat plate molds has 396 optical surface (that is, lens surface) forming regions having a diameter of 3.2 mm per mold (number density: 0.63 / cm 2 ).
  • the diameter of the optical surface forming portion included in the flat plate mold is 3.2 mm
  • the minimum distance between the optical surface forming regions is 10 mm
  • the total depth of the shallowest portions (D min ) is 150 ⁇ m
  • the optical The total depth (D max ) of the deepest part in the surface forming region was 550 ⁇ m.
  • the optical lens obtained by such a pair of flat plate molds is a biconvex lens. In this example, tension was applied to the hot press film in the transport direction in all steps from the transport step to the mold release step.
  • thermoplastic resin film In manufacturing the optical lens, a transport process was carried out to transport the thermoplastic resin film to a predetermined position in the transport direction along the longitudinal direction of the film. Then, the thermoplastic resin film is sandwiched between the pair of flat plate dies in an unheated state (80 ° C. or lower) (press pressure: 0.5 MPa), and while maintaining that state, 190 ° C. (press temperature, thermoplastic resin). the glass transition temperature Tg r + 51 ° C.) until flat die film was heated (mold heating step). Then, the thermoplastic resin film was hot-pressed at a press pressure of 6 MPa using a pair of flat plate dies to obtain a hot-press film (heat-pressing step).
  • the hot press film in the sandwiched state was cooled (die cooling step).
  • the flat plate mold was opened, the mold cooling process was completed, and the mold release process was started.
  • the molded film containing the plurality of optical lenses obtained through the mold release step was separated by punching with a round blade having an inner diameter of 8 mm to obtain 396 optical lenses.
  • the magnitude of the tension applied to the hot press film in the mold release step was 100 N (100 N / m) per 1 m of the width of the thermoplastic resin film.
  • the time (cycle time) required from the start of the transfer process to the completion of the mold release process was 180 seconds.
  • the obtained optical lens was subjected to various measurements and evaluations according to the above. The results are shown in Table 1.
  • Example 2 An optical lens was manufactured in the same manner as in Example 1 except that the tension applied to the thermoplastic resin film was changed as shown in Table 1. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 1.
  • Example 3 An optical lens was manufactured in the same manner as in Example 2 except that tension was not applied to the thermoplastic resin film in the mold heating step, the hot pressing step, and the mold cooling step. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 1. In steps other than the die heating step, the hot pressing step, and the die cooling step (that is, the transfer step and the mold release step), a state in which tension is applied to the thermoplastic resin film as in Example 2. It was.
  • Example 5 The magnitude of the tension applied to the hot press film in the mold release process, the thickness of the thermoplastic resin film, and the total depth (D min ) and the deepest part of the shallowest part of the flat plate mold used in the hot press process.
  • the total depth (D max ) of was changed as shown in Table 1.
  • An optical lens was manufactured in the same manner as in Example 1 except for these points. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 1. In Examples 4 and 5, the thermoplastic resin film was slightly broken at the stage after the mold release step, and the production efficiency was lowered.
  • Example 6 An optical lens was manufactured in the same manner as in Example 1 except that the temperature of the flat plate die (pressing temperature) in the hot pressing step was changed as shown in Table 1. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 1.
  • Example 7 An optical lens is manufactured in the same manner as in Example 1 except that the temperature of the flat plate die (pressing temperature) in the hot pressing process and the cooling temperature of the flat plate mold in the mold cooling process are changed as shown in Table 1. did. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 1.
  • Example 9 An optical lens was produced in the same manner as in Example 1 except that the thermoplastic resin film prepared as follows was used. Then, various measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.
  • thermoplastic resin film A thermoplastic resin (TOPAS6013 (manufactured by Polyplastics), glass transition temperature: 138 ° C.) containing a norbornene-ethylene random copolymer obtained by random addition polymerization using norbornene and ethylene as monomers was used in a film extruder ().
  • ⁇ 20 mm, manufactured by GSI Creos
  • melt at 260 ° C. extrude the molten resin from the T die, cool it, and have a maximum thickness of 202 ⁇ m, a minimum thickness of 198 ⁇ m, and a thickness variation of 4 ⁇ m.
  • a thermoplastic resin film having a width of 280 mm was obtained. The direction perpendicular to the width direction of the thermoplastic film is the longitudinal direction, and has a sufficient length for molding by the roll-to-roll molding method.
  • thermoplastic resin film having a width of 280 mm, a maximum thickness of 202 ⁇ m, a minimum thickness of 198 ⁇ m, and a thickness variation of 4 ⁇ m.
  • the direction perpendicular to the width direction of the thermoplastic film is the longitudinal direction, and has a sufficient length for molding by the roll-to-roll molding method.
  • Example 11 Using the thermoplastic resin film prepared as follows, the temperature of the flat plate mold in the hot pressing process (pressing temperature) and the cooling temperature of the flat plate mold in the mold cooling process were changed as shown in Table 1. An optical lens was manufactured in the same manner as in Example 1 except for the above. Then, various measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.
  • the direction perpendicular to the width direction of the thermoplastic film is the longitudinal direction, and has a sufficient length for molding by the roll-to-roll molding method.
  • Example 12 An optical lens was produced in the same manner as in Example 1 except that the thermoplastic resin film prepared as follows was used. Then, various measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.
  • thermoplastic resin film having a width of 280 mm, a maximum thickness of 202 ⁇ m, a minimum thickness of 198 ⁇ m, and a thickness variation of 4 ⁇ m.
  • the direction perpendicular to the width direction of the thermoplastic film is the longitudinal direction, and has a sufficient length for molding by the roll-to-roll molding method.
  • thermoplastic resin film An optical lens was produced in the same manner as in Example 1 except that the thermoplastic resin film prepared as follows was used. Then, various measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.
  • thermoplastic resin film having a width of 280 mm having a maximum thickness of 352 ⁇ m, a minimum thickness of 348 ⁇ m, and a thickness variation of 4 ⁇ m was obtained by extruding the molten resin from the T-die by melting it at 260 ° C. Obtained.
  • the direction perpendicular to the width direction of the thermoplastic film is the longitudinal direction, and has a sufficient length for molding by the roll-to-roll molding method.
  • Example 14 The flat plate mold is changed, the obtained optical lens is a convex meniscus lens, the total depth of the shallowest part of the flat plate mold (D min ) is 150 ⁇ m, and the total depth of the deepest part in the optical surface forming region (D).
  • An optical lens was manufactured in the same manner as in Example 1 except that max ) was set to 300 ⁇ m. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 1.
  • Example 1 An optical lens was manufactured in the same manner as in Example 1 except that no tension was applied to the thermoplastic resin film in the mold heating step, the hot pressing step, the mold cooling step, and the mold releasing step. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 2.
  • Example 2 Comparative Example 2 Except that the flat die at a die cooling process was not cooled to the glass transition temperature (Tg r) ° C. below the temperature of the thermoplastic resin film, in the same manner as in Example 1 to produce an optical lens. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 2.
  • Example 4 An optical lens was manufactured by carrying out an injection molding method according to each condition shown in Table 2.
  • the injection molding material the same thermoplastic resin containing the norbornene-based ring-opening polymer hydride as in Example 1 was used.
  • the injection molding apparatus "ROBOSHOT S2000i100A” manufactured by FANUC Corporation was used.
  • the injection molding die a 16-piece die capable of producing an optical lens having the same shape as in Example 1 was used. Using these, 160 optical lenses were manufactured by performing 10 manufacturing steps at an injection speed of 30 mm / sec and a holding pressure of 80 MPa. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 2.
  • NB-RO is a thermoplastic resin containing a norbornene-based ring-opening polymer hydride
  • NB / ET is a norbornene-ethylene random copolymer
  • PC norbornene-ethylene random copolymer
  • thermoplastic resin film, a heat press to obtain a hot press film was hot pressed by a pair of flat dies, molds for cooling the flat die to the glass transition temperature (Tg r) ° C. below the temperature
  • the film has low compound refractive index and high shape accuracy. It can be seen that the transmissive optical element (optical lens) could be efficiently manufactured.
  • no cooling Comparative Example 1 that did not tensioned the flat die at a die cooling process to the glass transition temperature (Tg r) ° C. The following temperatures for hot pressed film in the releasing step It can be seen that in Comparative Example 2 and Comparative Examples 3 and 4 in which the flat plate mold was not used, a transmission type optical element having low double refractive index and high shape accuracy could not be efficiently manufactured.

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Abstract

This transmissive optical element manufacturing method uses a thermoplastic resin film. The manufacturing method includes: a hot press step in which a thermoplastic resin film is hot-pressed in at least a pair of flat plate molds to obtain a hot-pressed film; a mold cooling step in which the pair of flat plate molds are cooled to no more than the glass transition temperature (Tgr) of the thermoplastic resin film to cool the heat-pressed film; and a mold releasing step in which, after the mold cooling step, the heat-pressed film is released from the pair of flat plate molds while a tensile force is applied to the heat-pressed film, to obtain a molded film that includes multiple transmissive optical elements.

Description

透過型光学素子の製造方法Manufacturing method of transmissive optical element
　本発明は、透過型光学素子の製造方法に関する。より具体的には、樹脂フィルムを用いた透過型光学素子の製造方法に関する。 The present invention relates to a method for manufacturing a transmissive optical element. More specifically, the present invention relates to a method for manufacturing a transmissive optical element using a resin film.
　近年、電子電気機器の軽量化、小型化、及び薄型化が進み、これらの電子電気機器に搭載されるカメラユニット等においても、薄型化及び小径化へのニーズが高まっている。また、このようなカメラユニット等においては、一層の高画質化のニーズがあり、これらの光学機器に備えられるレンズ及びプリズム等の透過型光学素子についても高性能であることが求められている。 In recent years, electronic and electrical equipment has become lighter, smaller, and thinner, and there is an increasing need for thinner and smaller diameter camera units and the like mounted on these electronic and electrical equipment. Further, in such a camera unit and the like, there is a need for further improvement in image quality, and transmission type optical elements such as lenses and prisms provided in these optical devices are also required to have high performance.
　従来、カメラユニット等に採用されるレンズ等の透過型光学素子は、一般的に、射出成形法により製造されてきた。しかしながら、射出成形法によりレンズを形成した場合、得られたレンズ内にウェルドラインが形成されることを完全に抑制することは困難であった。また、射出成形法に従って得られたレンズでは、複屈折が生じ易かった。このため、得られたレンズ中において、十分に高い光学的性能を発揮することが可能な領域の占める比率を十分に高めることが難しく、直径が１ｃｍに満たないような小径のレンズを射出成形法に従って形成しても、レンズとして十分に機能させることが難しかった。 Conventionally, transmissive optical elements such as lenses used in camera units and the like have generally been manufactured by an injection molding method. However, when a lens is formed by an injection molding method, it is difficult to completely suppress the formation of weld lines in the obtained lens. In addition, birefringence was likely to occur in the lens obtained according to the injection molding method. For this reason, it is difficult to sufficiently increase the ratio of the region capable of exhibiting sufficiently high optical performance in the obtained lens, and a lens having a small diameter of less than 1 cm is injected by an injection molding method. Even if it was formed according to the above, it was difficult to make it function sufficiently as a lens.
　そこで、近年、射出成形法以外の方法により、小径のレンズ等の透過型光学素子を製造する方法が検討されてきた。例えば、特許文献１には、樹脂シートを金型内で真空圧縮成形する光学レンズの製造方法が開示されている。特許文献１では、樹脂シートの厚み、金型の最深部の深さ、樹脂シートのガラス転移温度、及び成形時の金型の表面温度が特定の関係を満たすような条件下で成形することで、低複屈折性であるとともに、形状精度が高い光学レンズを効率的に製造することができる。 Therefore, in recent years, a method for manufacturing a transmissive optical element such as a lens having a small diameter has been studied by a method other than the injection molding method. For example, Patent Document 1 discloses a method for manufacturing an optical lens in which a resin sheet is vacuum-compressed in a mold. In Patent Document 1, the thickness of the resin sheet, the depth of the deepest part of the mold, the glass transition temperature of the resin sheet, and the surface temperature of the mold at the time of molding are molded under conditions that satisfy a specific relationship. It is possible to efficiently manufacture an optical lens having low birefringence and high shape accuracy.
国際公開第２０１７／１２６５９９号International Publication No. 2017/126599
　上述したように、電子電気機器に備えられるカメラユニット等には、一層の高画質化が求められている。また、電子電気機器の製造に際しては、当然、高い製造効率で製造することが求められている。しかしながら、特許文献１に記載の光学レンズの製造方法では、形状精度の高い光学レンズを、効率的に製造するという点で改善の余地があった。また、上述のように、従来から行われてきた射出成形法には、得られる光学レンズにおける複屈折の発生を抑制するという点で改善の余地があった。 As mentioned above, camera units and the like provided in electronic and electrical equipment are required to have higher image quality. In addition, when manufacturing electronic and electrical equipment, it is naturally required to manufacture with high manufacturing efficiency. However, the method for manufacturing an optical lens described in Patent Document 1 has room for improvement in that an optical lens having high shape accuracy can be efficiently manufactured. Further, as described above, there is room for improvement in the conventional injection molding method in that the occurrence of birefringence in the obtained optical lens is suppressed.
　そこで、本発明は、低複屈折性であるとともに形状精度の高い透過型光学素子を効率的に製造することが可能な、透過型光学素子の製造方法を提供することを目的とする。 Therefore, an object of the present invention is to provide a method for manufacturing a transmission type optical element capable of efficiently manufacturing a transmission type optical element having low birefringence and high shape accuracy.
　本発明者らは、上記目的を達成するために鋭意検討を行った。その結果、本発明者らは、金型を用いたプレス成形により樹脂フィルムを成形するにあたり、金型として平板金型を用い、且つ、製造工程における特定のタイミングで樹脂フィルムに対して張力をかけることで、低複屈折性であるとともに形状精度の高い透過型光学素子を効率的に製造することが可能となることを新たに見出し、本発明を完成させた。 The present inventors have conducted diligent studies in order to achieve the above object. As a result, when the resin film is formed by press molding using a mold, the present inventors use a flat plate mold as the mold and apply tension to the resin film at a specific timing in the manufacturing process. As a result, we have newly found that it is possible to efficiently manufacture a transmission type optical element having low birefringence and high shape accuracy, and completed the present invention.
　即ち、この発明は、上記課題を有利に解決することを目的とするものであり、本発明の透過型光学素子の製造方法は、熱可塑性樹脂フィルムを用いて透過型光学素子を製造する製造方法であって、前記熱可塑性樹脂フィルムを、少なくとも一対の平板金型により熱プレスして熱プレスフィルムを得る熱プレス工程と、前記一対の平板金型を前記熱可塑性樹脂フィルムのガラス転移温度（Ｔｇｒ）℃以下の温度まで冷却して、前記熱プレスフィルムを冷却する金型冷却工程と、前記金型冷却工程の後に、前記熱プレスフィルムを前記一対の平板金型から離型するにあたり、前記熱プレスフィルムに対して張力をかけながら離型して、複数の透過型光学素子を含む成形フィルムを得る離型工程と、を含むことを特徴とする。一対の平板金型を用いて熱プレスした熱可塑性樹脂フィルムを冷却した後に離型する際に、張力をかけながら離型することで、低複屈折性であるとともに形状精度の高い透過型光学素子を効率的に製造することが可能となる。
　なお、「熱可塑性樹脂フィルムのガラス転移温度（Ｔｇｒ）℃」は、ＪＩＳ Ｋ７１２１に基づき測定することができる。 That is, the present invention aims to advantageously solve the above problems, and the method for manufacturing a transmissive optical element of the present invention is a method for manufacturing a transmissive optical element using a thermoplastic resin film. A hot pressing step of hot-pressing the thermoplastic resin film with at least a pair of flat plate molds to obtain a hot-pressed film, and a glass transition temperature (Tg) of the pair of flat-plate molds of the thermoplastic resin film. r ) After the mold cooling step of cooling to a temperature of ° C. or lower to cool the hot press film and the mold cooling step, the hot press film is separated from the pair of flat plate molds. It is characterized by including a mold release step of obtaining a molded film containing a plurality of transmissive optical elements by releasing the heat press film while applying tension. A transmissive optical element with low birefringence and high shape accuracy by releasing the thermoplastic resin film that has been heat-pressed using a pair of flat plate dies while applying tension when the thermoplastic resin film is released after cooling. Can be efficiently manufactured.
Incidentally, "glass transition temperature of the thermoplastic resin film (Tg r) ° C." can be measured based on JIS K7121.
　また、本発明の透過型光学素子の製造方法が、前記熱プレス工程に先立って、前記熱可塑性樹脂フィルムを、所定の搬送方向に沿って搬送する搬送工程を更に含み、前記離型工程にて前記搬送方向に沿って張力をかけながら離型し、且つ、前記張力の大きさが、前記搬送方向に対して直交する方向の前記熱可塑性樹脂フィルムの幅１ｍあたり、１Ｎ以上２０００Ｎ以下であることが好ましい。張力の大きさを上記範囲内とすることで、一層効率的に、形状精度のばらつきの少ない複数の透過型光学素子を製造することができる。
　なお、「張力の大きさ」は、実施例に記載の方法により制御することができる。 Further, the method for manufacturing a transmissive optical element of the present invention further includes a transport step of transporting the thermoplastic resin film along a predetermined transport direction prior to the heat pressing step, and in the mold release step. The mold is released while applying tension along the transport direction, and the magnitude of the tension is 1 N or more and 2000 N or less per 1 m of the width of the thermoplastic resin film in the direction orthogonal to the transport direction. Is preferable. By setting the magnitude of the tension within the above range, it is possible to more efficiently manufacture a plurality of transmissive optical elements having little variation in shape accuracy.
The "magnitude of tension" can be controlled by the method described in the examples.
　また、本発明の透過型光学素子の製造方法において、前記一対の平板金型のうちの少なくとも一方は、直径が１ｍｍ以上１５ｍｍ以下である複数の光学面形成領域と、当該複数の光学面形成領域の各外周に隣接する領域である外周部形成領域とを含んでおり、且つ前記一対の平板金型の前記光学面形成領域及び前記外周部形成領域における最浅部の深さの合計が、５００μｍ以下であることが好ましい。上記条件を満たす平板金型を用いることで、強度に優れる透過型光学素子を効率的に製造することができる。 Further, in the method for manufacturing a transmission type optical element of the present invention, at least one of the pair of flat plate molds has a plurality of optical surface forming regions having a diameter of 1 mm or more and 15 mm or less, and the plurality of optical surface forming regions. The total depth of the optical surface forming region and the outermost portion forming region of the pair of flat plate molds is 500 μm, which includes the outer peripheral portion forming region which is a region adjacent to each outer peripheral portion of the above. The following is preferable. By using a flat plate mold satisfying the above conditions, a transmissive optical element having excellent strength can be efficiently manufactured.
　また、本発明の透過型光学素子の製造方法において、前記一対の平板金型のうちの少なくとも一方が、該平板金型の平面方向にて離散配置された複数の光学面形成領域を含み、該複数の光学面形成領域間の最小間隔が１．０ｍｍ以上であることが好ましい。上記条件を満たす平板金型を用いることで、透過型光学素子の製造効率を一層高めることができる。なお、「光学面形成領域の間の最小間隔」は、近接する光学面形成領域の輪郭間の、平板金型の平面方向における最短距離を意味する。なお、「平板金型の平面方向」とは、平板金型に設けられた凹部である光学面形成領域の開口部を含む平面に沿う方向を意味する。 Further, in the method for manufacturing a transmission type optical element of the present invention, at least one of the pair of flat plate dies includes a plurality of optical surface forming regions discretely arranged in the plane direction of the flat plate dies. The minimum distance between the plurality of optical surface forming regions is preferably 1.0 mm or more. By using a flat plate mold satisfying the above conditions, the manufacturing efficiency of the transmissive optical element can be further improved. The "minimum distance between the optical surface forming regions" means the shortest distance in the plane direction of the flat plate mold between the contours of the adjacent optical surface forming regions. The "planar direction of the flat plate mold" means a direction along the plane including the opening of the optical surface forming region, which is a recess provided in the flat plate mold.
　また、本発明の透過型光学素子の製造方法において、前記熱可塑性樹脂フィルムのガラス転移温度（Ｔｇｒ）が１００℃以上２００℃以下であることが好ましい。熱可塑性樹脂フィルムのガラス転移温度が上記範囲内であれば、得られる透過型光学素子の耐熱性及び形状精度を高めることができる。 In the method of manufacturing a transmission type optical element of the present invention preferably has a glass transition temperature of the thermoplastic resin film (Tg r) is less than 200 ° C. 100 ° C. or higher. When the glass transition temperature of the thermoplastic resin film is within the above range, the heat resistance and shape accuracy of the obtained transmissive optical element can be improved.
　また、本発明の透過型光学素子の製造方法において、前記熱プレス工程における前記一対の平板金型の温度が（Ｔｇｒ＋３０）℃以上（Ｔｇｒ＋７０）℃以下であることが好ましい。熱プレス工程における一対の平板金型の温度を上記範囲内とすることで、低複屈折性の透過型光学素子を一層効率的に製造することができる。 In the method of manufacturing a transmission type optical element of the present invention, it is preferable that the heat the in the press process temperature of the pair of flat plate mold (Tg r +30) ℃ or higher (Tg r +70) ℃ or less. By keeping the temperature of the pair of flat plate dies in the heat pressing process within the above range, a transmission type optical element having low birefringence can be manufactured more efficiently.
　また、本発明の透過型光学素子の製造方法では、前記金型冷却工程において、前記一対の平板金型を（Ｔｇｒ－１５）℃以下の温度まで冷却することが好ましい。金型冷却工程における一対の平板金型の温度を上記上限値以下とすることで、一層効率的に、形状精度のばらつきの少ない複数の透過型光学素子を製造することができる。 In the method of manufacturing a transmission type optical element of the present invention, in the mold cooling step, it is preferable to cool the pair of flat dies to (Tg r -15) ℃ or lower. By setting the temperature of the pair of flat plate molds in the mold cooling step to be equal to or lower than the above upper limit value, it is possible to more efficiently manufacture a plurality of transmissive optical elements having little variation in shape accuracy.
　また、本発明の透過型光学素子の製造方法において、前記熱可塑性樹脂フィルムが脂環構造含有樹脂を含むことが好ましい。熱可塑性樹脂フィルムが脂環構造含有樹脂を含んでいれば、透明性に優れる透過型光学素子を製造することができる。 Further, in the method for producing a transmissive optical element of the present invention, it is preferable that the thermoplastic resin film contains an alicyclic structure-containing resin. If the thermoplastic resin film contains an alicyclic structure-containing resin, a transmissive optical element having excellent transparency can be manufactured.
　また、本発明の透過型光学素子の製造方法において、前記一対の平板金型のうちの少なくとも一方が、０．１６個／ｃｍ２以上の個数密度で光学面形成領域を有することが好ましい。１００個以上の光学面形成領域を有する平板金型を用いることで、一層効率的に透過型光学素子を製造することができる。 Further, in the method for manufacturing a transmission type optical element of the present invention, it is preferable that at least one of the pair of flat plate dies has an optical surface forming region having a number density of 0.16 pieces / cm 2 or more. By using a flat plate mold having 100 or more optical surface forming regions, a transmission type optical element can be manufactured more efficiently.
　また、本発明の透過型光学素子の製造方法において、前記一対の平板金型の両方が、複数の光学面形成領域を有することが好ましい。光学面形成領域をそれぞれ有する一対の平板金型を用いて成形することで、両面が賦形された透過型光学素子を効率的に製造することができる。 Further, in the method for manufacturing a transmission type optical element of the present invention, it is preferable that both of the pair of flat plate molds have a plurality of optical surface forming regions. By molding using a pair of flat plate molds each having an optical surface forming region, it is possible to efficiently manufacture a transmissive optical element having both sides shaped.
　また、本発明の透過型光学素子の製造方法が、前記離型工程を経て得られた前記成形フィルムから、前記複数の透過型光学素子を分離する透過型光学素子分離工程を含むことが好ましい。成形フィルムから複数の透過型光学素子を分離する透過型光学素子分離工程を実施することで、一層効率的に透過型光学素子を製造することができる。 Further, it is preferable that the method for manufacturing a transmission type optical element of the present invention includes a transmission type optical element separation step of separating the plurality of transmission type optical elements from the molded film obtained through the mold release step. By carrying out the transmission type optical element separation step of separating a plurality of transmission type optical elements from the molded film, the transmission type optical element can be manufactured more efficiently.
　本発明の透過型光学素子の製造方法によれば、低複屈折性であるとともに形状精度の高い透過型光学素子を効率的に製造することができる。 According to the method for manufacturing a transmission type optical element of the present invention, it is possible to efficiently manufacture a transmission type optical element having low birefringence and high shape accuracy.
本発明の一例に係る透過型光学素子の製造方法を実施するために用いることができる透過型光学素子製造装置の概略構造を示す図である。It is a figure which shows the schematic structure of the transmission type optical element manufacturing apparatus which can be used for carrying out the manufacturing method of the transmission type optical element which concerns on one example of this invention. 本発明の一例に係る透過型光学素子である光学レンズの製造例の一つを説明するための概略図である。It is a schematic diagram for demonstrating one of the manufacturing examples of the optical lens which is a transmission type optical element which concerns on one example of this invention. 図２に示した形状とは異なる形状を有する光学レンズを製造する場合を説明するための概略図である。It is a schematic diagram for demonstrating the case of manufacturing the optical lens which has a shape different from the shape shown in FIG.
　以下、本発明の実施形態について詳細に説明する。本発明の透過型光学素子の製造方法によれば、光学レンズ及びプリズムといった透過型光学素子を好適に製造することができる。ここで、「光学レンズ」とは、光の屈折作用を示す透明体を意味する。また、「プリズム」とは、光の分散作用、屈折作用、全反射作用、及び／又は、複屈折作用を示す透明多面体を意味する。本発明の透過型光学素子の製造方法によれば、形状精度が高く、且つ低複屈折性の透過型光学素子を効率的に製造することができる。より具体的には、本発明の透過型光学素子の製造方法によれば、平凸レンズ、両凸レンズ、凸メニスカスレンズ、平凹レンズ、両凹レンズ、及び凹メニスカスレンズ、片面及び／又は両面が変曲点のある非球面レンズ等の種々の形状のレンズを好適に製造することができる。さらに、本発明の透過型光学素子の製造方法によれば、比較的小径の各種透過型光学素子を高い形状精度で製造することができるため、例えば、小型電子電気機器のカメラユニットのレンズとして好適に用いることができる光学レンズを効率的に製造することができる。 Hereinafter, embodiments of the present invention will be described in detail. According to the method for manufacturing a transmissive optical element of the present invention, a transmissive optical element such as an optical lens and a prism can be suitably manufactured. Here, the "optical lens" means a transparent body that exhibits a refracting action of light. Further, the “prism” means a transparent polyhedron exhibiting a light dispersion action, a refraction action, a total reflection action, and / or a birefringence action. According to the method for manufacturing a transmission type optical element of the present invention, it is possible to efficiently manufacture a transmission type optical element having high shape accuracy and low birefringence. More specifically, according to the method for manufacturing a transmissive optical element of the present invention, a plano-convex lens, a biconvex lens, a convex meniscus lens, a plano-concave lens, a biconcave lens, and a concave meniscus lens, one side and / or both sides are curved points. It is possible to suitably manufacture lenses having various shapes such as an aspherical lens having a lens. Further, according to the method for manufacturing a transmissive optical element of the present invention, various transmissive optical elements having a relatively small diameter can be manufactured with high shape accuracy, and therefore, for example, it is suitable as a lens for a camera unit of a small electronic / electrical device. It is possible to efficiently manufacture an optical lens that can be used in the above.
（透過型光学素子の製造方法）
　本発明の透過型光学素子の製造方法は、熱可塑性樹脂フィルムを用いて透過型光学素子を製造する製造方法である。そして、本発明の透過型光学素子の製造方法は、熱可塑性樹脂フィルムを、少なくとも一対の平板金型により熱プレスして熱プレスフィルムを得る「熱プレス工程」と、一対の平板金型を前記熱可塑性樹脂フィルムのガラス転移温度（Ｔｇｒ）℃以下の温度まで冷却して、熱プレスフィルムを冷却する「金型冷却工程」と、金型冷却工程の後に、熱プレスフィルムを一対の平板金型から離型するにあたり、熱プレスフィルムに対して張力をかけながら離型して、複数の透過型光学素子を含む成形フィルムを得る「離型工程」とを含むことを特徴とする。平板金型を用いて熱プレスした熱可塑性樹脂フィルムを冷却した後に離型する際に、張力をかけながら離型することで、低複屈折性であるとともに形状精度の高い透過型光学素子を効率的に製造することが可能となる。更に、本発明の透過型光学素子の製造方法は、熱プレス工程に先立って、熱可塑性樹脂フィルムを、所定の搬送方向に沿って搬送する搬送工程を含んでも良い。更にまた、本発明の透過型光学素子の製造方法は、離型工程の後段に、成形フィルムから複数の透過型光学素子を分離する透過型光学素子分離工程を含んでも良い。
　以下、各工程について詳述する。なお、各工程を実施する環境の気圧は特に限定されることなく、ＪＩＳＺ ８７０３に規定された標準状態の範囲内であり得る。なお、以下の各工程は、特に限定されることなくあらゆる手段により実施可能であるが、所謂、ロール・ツー・ロール方式の製造手段を用いて実施されることが好ましい。ロール・ツー・ロール方式の製造手段を用いて以下に説明する各工程を実施することで、透過型光学素子の製造効率を高めることができるからである。 (Manufacturing method of transmissive optical element)
The method for manufacturing a transmissive optical element of the present invention is a method for manufacturing a transmissive optical element using a thermoplastic resin film. The method for manufacturing a transmissive optical element of the present invention includes a "heat pressing step" in which a thermoplastic resin film is hot-pressed with at least a pair of flat plate dies to obtain a hot-pressed film, and the pair of flat-plate dies Upon cooling to the glass transition temperature (Tg r) ° C. below the temperature of the thermoplastic resin film, cooling the hot pressed film as "mold cooling step", after the mold cooling step, the hot press film pair flat gold When the mold is released from the mold, the heat press film is released from the mold while applying tension to obtain a molded film containing a plurality of transmissive optical elements, which is characterized by including a "mold release step". When a thermoplastic resin film that has been heat-pressed using a flat plate mold is cooled and then released, the mold is released while applying tension to efficiently produce a transmissive optical element with low birefringence and high shape accuracy. It becomes possible to manufacture the product. Further, the method for manufacturing a transmissive optical element of the present invention may include a transport step of transporting the thermoplastic resin film along a predetermined transport direction prior to the heat pressing step. Furthermore, the method for manufacturing a transmission type optical element of the present invention may include a transmission type optical element separation step of separating a plurality of transmission type optical elements from a molding film after the mold release step.
Hereinafter, each step will be described in detail. The atmospheric pressure in the environment in which each step is carried out is not particularly limited, and may be within the standard state specified in JISZ 8703. The following steps can be carried out by any means without particular limitation, but it is preferably carried out by using a so-called roll-to-roll manufacturing means. This is because the manufacturing efficiency of the transmissive optical element can be improved by carrying out each step described below using the roll-to-roll manufacturing means.
＜搬送工程＞
　搬送工程では、熱プレス工程に先立って、熱可塑性樹脂フィルムを、所定の搬送方向に沿って熱プレスを実施する位置まで搬送する。搬送方向は、熱可塑性フィルムの幅方向に対して直交する長手方向に沿う方向であることが好ましい。 <Transport process>
In the transfer step, prior to the heat press step, the thermoplastic resin film is conveyed to a position where the heat press is performed along a predetermined transfer direction. The transport direction is preferably a direction along a longitudinal direction orthogonal to the width direction of the thermoplastic film.
＜熱プレス工程＞
　熱プレス工程では、熱可塑性樹脂フィルムを、少なくとも一対の平板金型により熱プレスして熱プレスフィルムを得る。なお、熱プレス工程では、少なくとも一対の平板金型を用いる限りにおいて特に限定されることなく、一対の平板金型を用いて熱可塑性樹脂フィルムを熱プレスしてもよいし、複数対の平板金型により１枚の熱可塑性樹脂フィルムの異なる部分を同時又は時間差で熱プレスしても良い。本発明の透過型光学素子の製造方法において、射出成形法によらず、熱可塑性樹脂フィルムを平板金型を用いた熱プレスに供することで、得られる透過型光学素子における複屈折の発生を抑制することができる。 <Heat press process>
In the hot pressing step, the thermoplastic resin film is hot pressed with at least a pair of flat plate dies to obtain a hot pressing film. The heat pressing step is not particularly limited as long as at least a pair of flat plate dies are used, and the thermoplastic resin film may be hot pressed using a pair of flat plate dies, or a plurality of pairs of flat plate dies may be used. Different parts of one thermoplastic resin film may be heat-pressed simultaneously or at different times depending on the mold. In the method for manufacturing a transmissive optical element of the present invention, the occurrence of birefringence in the obtained transmissive optical element is suppressed by subjecting the thermoplastic resin film to a hot press using a flat plate die regardless of the injection molding method. can do.
＜＜熱可塑性樹脂フィルム＞＞
　熱可塑性樹脂フィルムとしては、熱可塑性である限りにおいて特に限定されることなく、既知のあらゆる熱可塑性樹脂を用いて形成されたフィルムを用いることができる。ここで、「フィルム」とは、表面及び裏面（即ち、主面）が、厚み分の距離を隔てて対向してなる形状を有する物体を意味する。熱可塑性樹脂フィルムを構成し得る熱可塑性樹脂としては、例えば、（メタ）アクリル樹脂、脂環構造含有樹脂、スチレン系樹脂、ポリカーボネート樹脂、ポリエステル樹脂、ポリエーテル樹脂、ウレタン樹脂、及びチオウレタン樹脂等が挙げられる。なお、「（メタ）アクリル」とは、アクリル及び／又はメタクリルを指す。そして、上述した熱可塑性樹脂は、１種類を単独で用いてもよいし、２種類以上を混合して用いてもよい。
　これらの中でも、透明性に優れる透過型光学素子が得られることから、熱可塑性樹脂フィルムが脂環構造含有樹脂を含むことが好ましい。 << Thermoplastic resin film >>
The thermoplastic resin film is not particularly limited as long as it is thermoplastic, and a film formed by using any known thermoplastic resin can be used. Here, the "film" means an object having a shape in which the front surface and the back surface (that is, the main surface) face each other with a distance corresponding to the thickness. Examples of the thermoplastic resin that can constitute the thermoplastic resin film include (meth) acrylic resin, alicyclic structure-containing resin, styrene resin, polycarbonate resin, polyester resin, polyether resin, urethane resin, and thiourethane resin. Can be mentioned. In addition, "(meth) acrylic" refers to acrylic and / or methacrylic. Then, one type of the above-mentioned thermoplastic resin may be used alone, or two or more types may be mixed and used.
Among these, it is preferable that the thermoplastic resin film contains an alicyclic structure-containing resin because a transmissive optical element having excellent transparency can be obtained.
　脂環構造含有樹脂とは、主鎖及び／又は側鎖に飽和環状炭化水素構造及び不飽和環状炭化水素構造等の脂環式構造を有する重合体である。なかでも、機械強度及び耐熱性に優れる透過型光学素子が得られ易いことから、シクロアルカン構造を主鎖に有するものが好ましい。脂環式構造含有樹脂を構成する重合体（以下、「脂環式構造含有重合体」とも称する）中の脂環式構造を有する繰り返し単位の割合は特に限定されないが、重合体に含まれる全繰り返し単位に対して、５０質量％以上が好ましく、７０質量％以上がより好ましく、９０質量％以上がさらに好ましい。脂環式構造を有する繰り返し単位の割合が５０質量％以上の脂環式構造含有重合体を用いることで、透明性及び耐熱性に優れる透過型光学素子が得られ易くなる。 The alicyclic structure-containing resin is a polymer having an alicyclic structure such as a saturated cyclic hydrocarbon structure and an unsaturated cyclic hydrocarbon structure in the main chain and / or the side chain. Among them, those having a cycloalkane structure in the main chain are preferable because it is easy to obtain a transmission type optical element having excellent mechanical strength and heat resistance. The proportion of repeating units having an alicyclic structure in the polymer constituting the alicyclic structure-containing resin (hereinafter, also referred to as “alicyclic structure-containing polymer”) is not particularly limited, but all contained in the polymer. With respect to the repeating unit, 50% by mass or more is preferable, 70% by mass or more is more preferable, and 90% by mass or more is further preferable. By using an alicyclic structure-containing polymer having an alicyclic structure and a ratio of repeating units of 50% by mass or more, it becomes easy to obtain a transmissive optical element having excellent transparency and heat resistance.
　脂環式構造含有重合体の具体例としては、ノルボルネン系重合体、単環の環状オレフィン系重合体、環状共役ジエン系重合体、ビニル脂環式炭化水素系重合体などが挙げられる。これらの中でも、得られる透過型光学素子の透明性、耐熱性、及び機械的強度を高める観点から、ノルボルネン系重合体が好ましい。なお、本明細書において、これらの重合体は、重合反応生成物だけでなく、その水素化物も意味するものである。 Specific examples of the alicyclic structure-containing polymer include a norbornene-based polymer, a monocyclic cyclic olefin-based polymer, a cyclic conjugated diene-based polymer, and a vinyl alicyclic hydrocarbon-based polymer. Among these, norbornene-based polymers are preferable from the viewpoint of enhancing the transparency, heat resistance, and mechanical strength of the obtained transmissive optical element. In addition, in this specification, these polymers mean not only the polymerization reaction product but also the hydride thereof.
　ノルボルネン系重合体は、ノルボルネン系モノマーの重合体又はその水素化物である。ノルボルネン系重合体としては、ノルボルネン系モノマーの開環重合体、ノルボルネン系モノマーとこれと開環共重合可能なその他のモノマーとの開環重合体、ノルボルネン系モノマーの付加重合体、ノルボルネン系モノマーとこれと共重合可能なその他のモノマーとの付加重合体、及びこれらの重合体の水素化物などが挙げられる。なかでも、ノルボルネン系モノマーの開環重合体水素化物（即ち、ノルボルネン系開環重合体水素化物）が好ましい。ノルボルネン系開環重合体水素化物を用いて形成された熱可塑性樹脂フィルムを用いることで、得られる透過型光学素子の透明性、耐熱性、及び機械的強度等を一層高めることができると共に、透過型光学素子を製造する際の離型性及び転写性を高めることができる。 The norbornene-based polymer is a polymer of norbornene-based monomers or a hydride thereof. Examples of the norbornene-based polymer include a ring-opening polymer of a norbornene-based monomer, a ring-opening polymer of a norbornene-based monomer and another monomer capable of ring-opening copolymerization, an addition polymer of a norbornene-based monomer, and a norbornene-based monomer. Examples thereof include addition polymers with other monomers copolymerizable with this, and hydrides of these polymers. Of these, a ring-opening polymer hydride of a norbornene-based monomer (that is, a norbornene-based ring-opening polymer hydride) is preferable. By using a thermoplastic resin film formed by using a norbornene-based ring-opening polymer hydride, the transparency, heat resistance, mechanical strength, etc. of the obtained transmissive optical element can be further improved, and the transmissivity can be further improved. It is possible to improve the releasability and transferability when manufacturing a mold optical element.
　ノルボルネン系モノマーとしては、ビシクロ［２．２．１］ヘプト－２－エン（慣用名：ノルボルネン）及びその誘導体、トリシクロ［４．３．０１，６．１２，５］デカ－３，７－ジエン（慣用名ジシクロペンタジエン）及びその誘導体、７，８－ベンゾトリシクロ［４．３．０．１２，５］デカ－３－エン（慣用名メタノテトラヒドロフルオレン：１，４－メタノ－１，４，４ａ，９ａ－テトラヒドロフルオレンともいう）及びその誘導体、テトラシクロ［４．４．０．１２，５．１７，１０］ドデカ－３－エン（慣用名：テトラシクロドデセン）及びその誘導体、などが挙げられる。誘導体に含まれうる置換基としては、アルキル基、アルキレン基、ビニル基、アルコキシカルボニル基、アルキリデン基などが挙げられる。例えば、ノルボルネン系モノマーとしての誘導体としては、８－メトキシカルボニル－テトラシクロ［４．４．０．１２，５．１７，１０］ドデカ－３－エン、８－メチル－８－メトキシカルボニル－テトラシクロ［４．４．０．１２，５．１７，１０］ドデカ－３－エン、８－エチリデン－テトラシクロ［４．４．０．１２，５．１７，１０］ドデカ－３－エンなどが挙げられる。これらのノルボルネン系モノマーは、１種単独であるいは２種以上を組み合わせて用いることができる。 The norbornene-based monomer, bicyclo [2.2.1] hept-2-ene (common name: norbornene) and derivatives thereof, tricyclo [4.3.0 1,6. 1 2,5 ] Deca-3,7-diene (trivial name dicyclopentadiene) and its derivatives, 7,8-benzotricyclo [4.3.0.1 2,5 ] deca-3-ene (trivial name) Metanotetrahydrofluorene: 1,4-methano-1,4,4a, 9a-also referred to as tetrahydrofluorene) and its derivatives, tetracyclo [4.4.0.1 2,5 . 17, 10 ] Dodeca-3-ene (common name: tetracyclododecene) and its derivatives, and the like. Examples of the substituent that can be contained in the derivative include an alkyl group, an alkylene group, a vinyl group, an alkoxycarbonyl group, and an alkylidene group. For example, as a derivative as a norbornene-based monomer, 8-methoxycarbonyl-tetracyclo [4.4.0.1 2,5 . 1 7, 10 ] Dodeca-3-ene, 8-methyl-8-methoxycarbonyl-tetracyclo [4.4.0.1 2,5 . 1 7, 10 ] Dodeca-3-ene, 8-ethylidene-tetracyclo [4.4.0.1 2,5 . 17 and 10 ] Dodeca-3-en and the like. These norbornene-based monomers can be used alone or in combination of two or more.
　ノルボルネン系モノマーと開環共重合可能なその他のモノマーとしては、シクロヘキセン、シクロヘプテン、及びシクロオクテンなどの単環の環状オレフィン系単量体などが挙げられる。ノルボルネン系モノマーと付加共重合可能なその他のモノマーとしては、エチレン、プロピレン、１－ブテン、１－ペンテン、及び１－ヘキセンなどの炭素数２～２０のα－オレフィン並びにこれらの誘導体；シクロブテン、シクロペンテン、シクロヘキセン、シクロオクテン、及び３ａ，５，６，７ａ－テトラヒドロ－４，７－メタノ－１Ｈ－インデンなどのシクロオレフィン並びにこれらの誘導体；１，４－ヘキサジエン、４－メチル－１，４－ヘキサジエン、５－メチル－１，４－ヘキサジエン、及び１，７－オクタジエンなどの非共役ジエン；などが挙げられる。 Examples of other monomers that can be open-ring copolymerized with the norbornene-based monomer include monocyclic cyclic olefin-based monomers such as cyclohexene, cycloheptene, and cyclooctene. Other monomers that can be additionally copolymerized with norbornene-based monomers include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, 1-butene, 1-pentene, and 1-hexene, and derivatives thereof; cyclobutene and cyclopentene. , Cyclohexene, cyclooctene, and cycloolefins such as 3a, 5,6,7a-tetrahydro-4,7-methano-1H-indene and derivatives thereof; 1,4-hexadiene, 4-methyl-1,4-hexadiene. , 5-Methyl-1,4-hexadiene, and non-conjugated diene such as 1,7-octadiene; and the like.
　上述のようなノルボルネン系モノマーを含む開環重合体及び付加重合体は、公知の触媒の存在下で重合させることにより合成することができる。また、これらの水素化物は、公知の水素化触媒を用いた水素化反応により、得ることができる。 The ring-opening polymer and the addition polymer containing the norbornene-based monomer as described above can be synthesized by polymerizing in the presence of a known catalyst. Further, these hydrides can be obtained by a hydrogenation reaction using a known hydrogenation catalyst.
　なお、単環の環状オレフィン系重合体、環状共役ジエン系重合体、及びビニル脂環式炭化水素系重合体としては、例えば、国際公開第２０１７／１２６５９９号に記載されたものが挙げられる。 Examples of the monocyclic cyclic olefin polymer, the cyclic conjugated diene polymer, and the vinyl alicyclic hydrocarbon polymer include those described in International Publication No. 2017/126599.
　また、脂環式構造含有重合体として、市販品を使用することもできる。市販品としては、日本ゼオン社製、ＺＥＯＮＥＸ（登録商標）、三井化学社製、ＡＰＥＬ（登録商標）、ＪＳＲ社製、ＡＲＴＯＮ（登録商標）、ポリプラスチックス社製、ＴＯＰＡＳ（登録商標）などが挙げられる。 A commercially available product can also be used as the alicyclic structure-containing polymer. Commercially available products include Zeon Corporation, ZEONEX (registered trademark), Mitsui Chemicals, APEL (registered trademark), JSR, ARTON (registered trademark), Polyplastics (registered trademark), etc. Can be mentioned.
　熱可塑性樹脂フィルムは、上述したような樹脂成分以外の成分を含有するものであってもよい。樹脂成分以外の成分としては、光安定剤、紫外線吸収剤、酸化防止剤、離型剤、帯電防止剤、炭素材料（カーボン等）、顔料、及び、染料等の添加剤が挙げられる。これらの成分の配合量は、特に限定されず適宜決定することができる。例えば、これらの添加剤の合計量は、樹脂成分を１００質量％として、例えば２０質量％以下、好ましくは１０質量％以下でありうる。 The thermoplastic resin film may contain a component other than the resin component as described above. Examples of components other than the resin component include additives such as light stabilizers, ultraviolet absorbers, antioxidants, mold release agents, antistatic agents, carbon materials (carbon and the like), pigments, and dyes. The blending amount of these components is not particularly limited and can be appropriately determined. For example, the total amount of these additives may be, for example, 20% by mass or less, preferably 10% by mass or less, assuming that the resin component is 100% by mass.
　なお、熱可塑性樹脂フィルムの製造方法としては、特に限定されることなく、従来公知の適宜な方法を採用することができる。例えば、所定の成分を混合して熱可塑性樹脂フィルム製造用の成形材料を得、これを用いて、溶融押出成形法、溶融流延成形法、射出成形法等により、熱可塑性樹脂フィルムを得ることができる。 The method for producing the thermoplastic resin film is not particularly limited, and a conventionally known appropriate method can be adopted. For example, a predetermined component is mixed to obtain a molding material for manufacturing a thermoplastic resin film, and the thermoplastic resin film is obtained by a melt extrusion molding method, a melt casting method, an injection molding method, or the like. Can be done.
［熱可塑性樹脂フィルムのガラス転移温度］
　熱可塑性樹脂フィルムのガラス転移温度（Ｔｇｒ）は、特に限定されないが、１００℃以上が好ましく、１２０℃以上がより好ましく、２００℃以下が好ましく、１６０℃以下がより好ましい。熱可塑性樹脂フィルムのガラス転移温度（Ｔｇｒ）が上記下限値以上であれば、得られる透過型光学素子の形状精度を一層高めることができる。また、熱可塑性樹脂フィルムのガラス転移温度（Ｔｇｒ）が上記上限値以下であれば、透過型光学素子の生産効率を高めると共に、形状精度を一層高めることができる。 [Glass transition temperature of thermoplastic resin film]
The glass transition temperature of the thermoplastic resin film (Tg r) is not particularly limited, preferably at least 100 ° C., more preferably at least 120 ° C., preferably 200 ° C. or less, more preferably 160 ° C. or less. If the glass transition temperature of the thermoplastic resin film (Tg r) is less than the above lower limit, it is possible to further improve the shape accuracy of the transmission-type optical element obtained. The glass transition temperature of the thermoplastic resin film (Tg r) is not more than the above upper limit, to increase the production efficiency of the transmission type optical element, it is possible to increase the shape accuracy even.
［熱可塑性樹脂フィルムの厚み］
　ここで、熱可塑性樹脂フィルムは、一枚のフィルム内でも、厚みにばらつきがある場合がある。得られる透過型光学素子の形状精度のばらつきを効果的に抑制する観点から、熱可塑性樹脂フィルムは、厚みばらつきが１０μｍ以内であることが好ましく、５μｍ以内であることがより好ましい。当然、完全に厚みが均一なフィルムでは、厚みばらつきは０μｍであるが、一般的には、厚みばらつきは、０．５μｍ以上であり得る。なお、熱可塑性樹脂フィルムの厚みばらつきは、熱可塑性樹脂フィルムの最大厚みと最小厚みとの差分であり、実施例に記載の方法に従って測定することができる。 [Thickness of thermoplastic resin film]
Here, the thickness of the thermoplastic resin film may vary even within a single film. From the viewpoint of effectively suppressing the variation in the shape accuracy of the obtained transmissive optical element, the thickness variation of the thermoplastic resin film is preferably 10 μm or less, and more preferably 5 μm or less. Naturally, in a film having a completely uniform thickness, the thickness variation is 0 μm, but in general, the thickness variation can be 0.5 μm or more. The thickness variation of the thermoplastic resin film is the difference between the maximum thickness and the minimum thickness of the thermoplastic resin film, and can be measured according to the method described in Examples.
　熱可塑性樹脂フィルムの厚みは、製造する透過型光学素子の直径に応じて、適宜選択することができる。例えば、熱可塑性樹脂フィルムの厚みは、通常５０μｍ以上であり、好ましくは７０μｍ以上であり、通常５００μｍ以下であり、好ましくは４００μｍ以下である。なお、熱可塑性樹脂フィルムに厚みばらつきがある場合には、熱可塑性樹脂フィルムの厚みは、実施例に記載したように、ランダムに選定した複数の測定点における厚みの単純算術平均の値に相当する。 The thickness of the thermoplastic resin film can be appropriately selected according to the diameter of the transmissive optical element to be manufactured. For example, the thickness of the thermoplastic resin film is usually 50 μm or more, preferably 70 μm or more, usually 500 μm or less, and preferably 400 μm or less. When the thickness of the thermoplastic resin film varies, the thickness of the thermoplastic resin film corresponds to the simple arithmetic mean value of the thicknesses at a plurality of randomly selected measurement points as described in the examples. ..
＜＜平板金型＞＞
［形状］
　本発明の透過型光学素子の製造方法で用いる一対の平板金型は、少なくとも一方が光学面形成領域である凹部を複数個有している限りにおいて特に限定されることなく、あらゆる形状であり得る。複数の光学面形成領域は、平板金型の平面方向にて離散配置されてなる。複数の光学面形成領域は、平板金型の平面方向にて、等間隔で離隔して配置されていることが好ましい。 << Flat plate mold >>
[shape]
The pair of flat plate molds used in the method for manufacturing a transmissive optical element of the present invention is not particularly limited as long as at least one of them has a plurality of recesses which are optical surface forming regions, and may have any shape. .. The plurality of optical surface forming regions are discretely arranged in the plane direction of the flat plate mold. It is preferable that the plurality of optical surface forming regions are arranged at equal intervals in the plane direction of the flat plate mold.
　ここで、本発明の透過型光学素子の製造方法に従って形成される透過型光学素子は、凹面、凸面、又は、変曲点のある非球面等の少なくとも一つの光学面と、かかる光学面に隣接する領域であって、透過型光学素子を保持するための保持部材に対する取付領域等として機能し得る領域である外周部（フランジ部）とを有し得る。外周部は、透過型光学素子の光軸に対して垂直または略垂直であり得る。なお、「透過型光学素子の光軸」は、透過型光学素子の中心を通り、且つ光学面に対して垂直な軸線に相当する。例えば、透過型光学素子の形状について一つの回転対称軸を定義し得る場合には、かかる回転対称軸が光軸に一致する。そして、光学面及び外周部を有する形状の透過型光学素子を形成するための平板金型は、複数の光学面形成領域と、当該複数の光学面形成領域の各外周に隣接する領域である外周部形成領域とを含んでなる。外周部形成領域の少なくとも一部は、平板金型の平面方向に対して平行な水平領域であり得る。さらに、平板金型は、任意で、外周部に隣接する領域であって、後述する透過型光学素子分離工程で分離されて得られた透過型光学素子には含まれない領域を形成するための周縁部（マージン部）を有していても良い。 Here, the transmissive optical element formed according to the method for manufacturing a transmissive optical element of the present invention is adjacent to at least one optical surface such as a concave surface, a convex surface, or an aspherical surface having an inflection point, and the optical surface. It may have an outer peripheral portion (flange portion) which is a region to function as a mounting region or the like for a holding member for holding the transmissive optical element. The outer peripheral portion may be perpendicular to or substantially perpendicular to the optical axis of the transmissive optical element. The "optical axis of the transmissive optical element" corresponds to an axis that passes through the center of the transmissive optical element and is perpendicular to the optical surface. For example, when one rotational symmetry axis can be defined for the shape of the transmissive optical element, the rotational symmetry axis coincides with the optical axis. The flat plate mold for forming a transmissive optical element having an optical surface and an outer peripheral portion has a plurality of optical surface forming regions and an outer circumference which is a region adjacent to each outer periphery of the plurality of optical surface forming regions. It includes a part-forming region. At least a part of the outer peripheral portion forming region may be a horizontal region parallel to the plane direction of the flat plate mold. Further, the flat plate mold is optionally used to form a region adjacent to the outer peripheral portion and not included in the transmissive optical element separated by the transmissive optical element separation step described later. It may have a peripheral edge portion (margin portion).
　一対の平板金型は、両方が、それぞれ複数の光学面形成領域を有していてもよい。光学面形成領域をそれぞれ有する一対の平板金型を用いて成形することで、両面が賦形された透過型光学素子を効率的に製造することができるからである。なお、一対の平板金型の各形状は、当然、製造する透過型光学素子の形状に応じて、同一であっても、相異なっていても良い。 Both of the pair of flat plate molds may have a plurality of optical surface forming regions. This is because a transmissive optical element having both sides shaped can be efficiently manufactured by molding using a pair of flat plate dies each having an optical surface forming region. Of course, the shapes of the pair of flat plate molds may be the same or different depending on the shape of the transmission type optical element to be manufactured.
　そして、透過型光学素子の製造効率を向上する観点から、一対の平板金型のうちの少なくとも一方における光学面形成領域の個数密度が、０．１６個／ｃｍ２以上であることが好ましく、０．３２個／ｃｍ２以上であることがより好ましい。なお、個数密度が０．１６個／ｃｍ２である場合には、２１０ｍｍ×２９７ｍｍ（Ａ４サイズ）の領域につき約１００個の光学面形成領域が存在し、個数密度が０．３２個／ｃｍ２である場合には、Ａ４サイズの領域につき約２００個の光学面形成領域が存在することとなる。よって、例えば、光学面形成領域の個数密度が上記下限値以上であるＡ４サイズ程度の平板金型を用いて透過型光学素子を製造した場合には、１度の熱プレス工程を含む１サイクルの処理を行うことで、１００個以上の透過型光学素子を得ることができるため、透過型光学素子の製造効率を一層高めることができる。なお、一対の平板金型のうちの少なくとも一方における光学面形成領域の個数密度の上限値は、特に限定されない。例えば、１サイクル当たりに製造されうる透過型光学素子の個数が、２０００個以下となるような個数密度であり得る。 From the viewpoint of improving the manufacturing efficiency of the transmission type optical element, the number density of the optical surface forming region in at least one of the pair of flat plate molds is preferably 0.16 pieces / cm 2 or more, and is 0. More preferably, it is .32 pieces / cm 2 or more. When the number density is 0.16 / cm 2 , there are about 100 optical surface forming regions per 210 mm × 297 mm (A4 size) region, and the number density is 0.32 / cm 2. In the case of, there are about 200 optical surface forming regions for each A4 size region. Therefore, for example, when a transmissive optical element is manufactured using a flat plate die of about A4 size in which the number density of the optical surface forming region is equal to or higher than the above lower limit value, one cycle including one heat pressing step is performed. By performing the treatment, 100 or more transmissive optical elements can be obtained, so that the manufacturing efficiency of the transmissive optical elements can be further improved. The upper limit of the number density of the optical surface forming region in at least one of the pair of flat plate molds is not particularly limited. For example, the number density may be such that the number of transmissive optical elements that can be manufactured per cycle is 2000 or less.
［光学面形成領域の直径］
　一対の平板金型の少なくとも一方に設けられた複数の光学面形成領域の直径は、直径が１ｍｍ以上１５ｍｍ以下であることが好ましい。直径が１ｍｍ以上であれば、得られる透過型光学素子により十分な光量の光線を透過させることができる。よって、例えば透過型光学素子として光学レンズを製造した場合には、得られた光学レンズのレンズ径が充分に大きく、当該光学レンズが含まれる光学系の後段側に備えられたセンサー等の受光素子まで充分な光量の光線を到達させることができる。また、直径が１５ｍｍ以下である透過型光学素子は、大きすぎず、カメラユニット等に取り付けるために適度なサイズである。なお、光学面形成領域の直径は、平板金型に設けられた凹部である光学面形成領域の開口部の直径である。即ち、光学面形成領域の直径は、凹部を深さ方向に見た場合に、最も大きい直径に相当する。
　なお、本発明の透過型光学素子の製造方法によれば、高い形状精度で透過型光学素子を成形することができるため、平板金型の光学面形成領域の直径は、実質的に、得られる透過型光学素子の光学面の直径に相当し得る。 [Diameter of optical surface formation region]
The diameter of the plurality of optical surface forming regions provided on at least one of the pair of flat plate molds is preferably 1 mm or more and 15 mm or less. When the diameter is 1 mm or more, a sufficient amount of light can be transmitted by the obtained transmissive optical element. Therefore, for example, when an optical lens is manufactured as a transmissive optical element, the lens diameter of the obtained optical lens is sufficiently large, and a light receiving element such as a sensor provided on the rear side of the optical system including the optical lens. It is possible to reach a sufficient amount of light rays. Further, the transmissive optical element having a diameter of 15 mm or less is not too large and has an appropriate size for being attached to a camera unit or the like. The diameter of the optical surface forming region is the diameter of the opening of the optical surface forming region, which is a recess provided in the flat plate mold. That is, the diameter of the optical surface forming region corresponds to the largest diameter when the recess is viewed in the depth direction.
According to the method for manufacturing a transmissive optical element of the present invention, the transmissive optical element can be formed with high shape accuracy, so that the diameter of the optical surface forming region of the flat plate mold can be substantially obtained. It can correspond to the diameter of the optical surface of the transmissive optical element.
［光学面形成領域の間の最小間隔］
　さらに、一対の平板金型の少なくとも一方に設けられた複数の光学面形成領域の間の最小間隔は、１．０ｍｍ以上が好ましく、３．０ｍｍ以上がより好ましく、５０ｍｍ以下が好ましい。複数の光学面形成領域の間の最小間隔が上記下限値以上であれば、後述する透過型光学素子分離工程にて、成形フィルムから各透過型光学素子を分離する際に効率的に分離することができ、透過型光学素子の製造効率を高めることができる。また、複数の光学面形成領域の間の最小間隔が上記上限値以下であれば、一度の熱プレス工程を経て得られる成形フィルム中における透過型光学素子の個数密度を十分に高めることができ、透過型光学素子の製造効率を一層高めることができる。
　なお、上述したように、複数の光学面形成領域は、平板金型の平面方向にて、等間隔で離隔して配置されていることが好ましい。 [Minimum spacing between optical surface formation regions]
Further, the minimum distance between the plurality of optical surface forming regions provided on at least one of the pair of flat plate molds is preferably 1.0 mm or more, more preferably 3.0 mm or more, and preferably 50 mm or less. When the minimum distance between the plurality of optical surface forming regions is equal to or greater than the above lower limit value, each transmission type optical element is efficiently separated from the molded film in the transmission type optical element separation step described later. It is possible to improve the manufacturing efficiency of the transmissive optical element. Further, when the minimum distance between the plurality of optical surface forming regions is not more than the above upper limit value, the number density of the transmission type optical elements in the molded film obtained through one heat pressing step can be sufficiently increased. The manufacturing efficiency of the transmissive optical element can be further improved.
As described above, it is preferable that the plurality of optical surface forming regions are arranged at equal intervals in the plane direction of the flat plate mold.
［金型の深さ］
　さらに、一対の平板金型の光学面形成領域及び外周部形成領域における最浅部の深さの合計は、５００μｍ以下が好ましく、４００μｍ以下がより好ましく、３００μｍ以下がさらに好ましく、５０μｍ以上が好ましい。ここで、一対の平板金型の光学面形成領域及び外周部形成領域における最浅部の深さの合計（後述する図２、図３におけるＤmin）は、得られる透過型光学素子における最薄部の厚みに相当する。なお、図２及び図３では、Ｄminが、それぞれ、一対の平板金型の外周部形成領域内に位置するものとして図示している。しかし、例えば、目的とする透過型光学素子が両凹レンズである場合であって、外周部形成領域の厚みよりも、光学面形成領域の最薄部の厚みの方が薄いような形状を有するものである場合には、Ｄminは、一対の平板金型の光学面形成領域内に位置することとなる。そして、光学面形成領域及び外周部形成領域における最浅部の深さの合計が上記上限値以下であれば、得られる透過型光学素子をコンパクト化することができる。例えば、透過型光学素子として光学レンズを製造した場合には、かかる光学レンズを含むレンズユニットの厚さを薄くすることができる。また、光学面形成領域及び外周部形成領域における最浅部の深さの合計が上記下限値以上であれば、得られる透過型光学素子に外的に力が加えられた場合に局所的に応力が集中することを抑制することで、透過型光学素子の機械強度を高めることができる。さらにまた、外周部形成領域における最浅部の深さの合計が上記下限値以上であれば、成形フィルムの強度を確保して、搬送途中等の想定外のタイミングで成形フィルムに亀裂等が生じることを抑制して、透過型光学素子の製造効率を高めることができる。
　なお、「平板金型の外周部形成領域における最浅部の深さの合計」は、成形時に一対の平板金型を対向させて相互に配置又は接触させた場合の、外周部形成領域における金型間の最短距離に相当する。 [Die depth]
Further, the total depth of the shallowest portion in the optical surface forming region and the outer peripheral portion forming region of the pair of flat plate molds is preferably 500 μm or less, more preferably 400 μm or less, further preferably 300 μm or less, and preferably 50 μm or more. Here, the total depth of the shallowest portions in the optical surface forming region and the outer peripheral portion forming region of the pair of flat plate molds (D min in FIGS. 2 and 3 described later) is the thinnest in the obtained transmission type optical element. Corresponds to the thickness of the part. In addition, in FIG. 2 and FIG. 3, D min is shown as being located in the outer peripheral portion forming region of the pair of flat plate molds, respectively. However, for example, when the target transmission type optical element is a biconcave lens, the thickness of the thinnest portion of the optical surface forming region is thinner than the thickness of the outer peripheral portion forming region. In the case of, D min is located in the optical surface forming region of the pair of flat plate molds. When the total depth of the shallowest portion in the optical surface forming region and the outer peripheral portion forming region is not more than the above upper limit value, the obtained transmissive optical element can be made compact. For example, when an optical lens is manufactured as a transmissive optical element, the thickness of the lens unit including the optical lens can be reduced. Further, if the total depth of the shallowest portion in the optical surface forming region and the outer peripheral portion forming region is equal to or more than the above lower limit value, the stress is locally applied when an external force is applied to the obtained transmissive optical element. The mechanical strength of the transmissive optical element can be increased by suppressing the concentration of the stress. Furthermore, if the total depth of the shallowest portion in the outer peripheral portion forming region is equal to or greater than the above lower limit value, the strength of the molded film is ensured, and cracks or the like occur in the molded film at an unexpected timing such as during transportation. This can be suppressed and the manufacturing efficiency of the transmissive optical element can be improved.
The "total depth of the shallowest portion in the outer peripheral portion forming region of the flat plate mold" is the mold in the outer peripheral portion forming region when a pair of flat plate dies are arranged or brought into contact with each other at the time of molding. Corresponds to the shortest distance between molds.
　また、一対の平板金型の光学面形成領域における最深部の深さの合計（Ｄmax）は、得られる透過型光学素子における最厚部の厚みに相当する。なお、「平板金型の光学面形成領域における最深部の深さの合計」は、一対の平板金型を成型のために対向させて相互に配置又は接触させた場合の、光学面形成領域における金型間の最大距離に相当する。一対の平板金型の光学面形成領域における最深部の深さの合計は、最浅部の深さの合計よりも値が大きく、例えば、５０μｍ超１０００μｍ以下であり得る。 Further, the total depth (D max ) of the deepest portion in the optical surface forming region of the pair of flat plate molds corresponds to the thickness of the thickest portion in the obtained transmissive optical element. The "total depth of the deepest portion in the optical surface forming region of the flat plate mold" is the optical surface forming region when a pair of flat plate molds are opposed to each other for molding and arranged or brought into contact with each other. Corresponds to the maximum distance between molds. The total depth of the deepest portion in the optical surface forming region of the pair of flat plate molds is larger than the total depth of the shallowest portion, and can be, for example, more than 50 μm and 1000 μm or less.
［熱可塑性樹脂フィルムの厚みと平板金型の形状との関係］
　本発明の透過型光学素子の製造方法において、熱可塑性樹脂フィルムの厚み（ランダムに選定した１００以上の測定点における厚みの単純算術平均の値）Ｔｆが、一対の平板金型の外周部形成領域における最浅部の深さの合計（Ｄmin）以上、光学面形成領域における最深部の深さの合計（Ｄmax）以下であることが好ましい。より好ましくは、熱可塑性樹脂フィルムの厚みＴｆが、（Ｄmin×１．１）≦Ｔｆ≦（Ｄmax×０．９）を満たすことが好ましい。熱可塑性樹脂フィルムの厚みＴｆが上記上限値以下であれば、透過型光学素子の最薄部の厚みを、所望の厚みまで効率的に薄肉化することができる。また、熱可塑性樹脂フィルムの厚みＴｆが上記下限値以上であれば、特に、一対の平板金型内の光学面形成領域にて良好に熱可塑性樹脂を充填することができるため、得られる透過型光学素子の形状精度を一層高めることができる。 [Relationship between the thickness of the thermoplastic resin film and the shape of the flat plate mold]
In the method for manufacturing a transmissive optical element of the present invention, the thickness T f of the thermoplastic resin film (the value of the simple arithmetic mean of the thicknesses at 100 or more measurement points randomly selected) is formed on the outer periphery of the pair of flat plate molds. It is preferable that the total depth of the shallowest portion in the region (D min ) or more and the total depth of the deepest portion in the optical surface forming region (D max ) or less. More preferably, the thickness T f of the thermoplastic resin film satisfies (D min × 1.1) ≦ T f ≦ (D max × 0.9). When the thickness T f of the thermoplastic resin film is not more than the above upper limit value, the thickness of the thinnest portion of the transmissive optical element can be efficiently thinned to a desired thickness. Further, when the thickness T f of the thermoplastic resin film is at least the above lower limit value, the thermoplastic resin can be satisfactorily filled in the optical surface forming region in the pair of flat plate molds, so that the obtained transmission can be obtained. The shape accuracy of the mold optical element can be further improved.
［金型温度］
　熱プレス工程における一対の平板金型の温度は、（Ｔｇｒ＋３０）℃以上が好ましく、（Ｔｇｒ＋４０）℃以上がより好ましく、（Ｔｇｒ＋７０）℃以下が好ましく、（Ｔｇｒ＋６０）℃以下がより好ましい。熱プレス工程における一対の平板金型の温度が上記下限値以上であれば、得られる透過型光学素子における複屈折の発生を一層良好に抑制することができる。熱プレス工程における一対の平板金型の温度が上記上限値以下であれば、一層効率的に透過型光学素子を製造することができる。
　なお、熱プレス工程は、即ち、熱可塑性樹脂フィルムを一対の平板金型で加熱しながらプレスするための動作過程において、所定のプレス圧を平板金型に対して印加して熱可塑性樹脂フィルムを熱プレスする期間を指す。ここで、かかる熱プレス工程と、上述した搬送工程との間に、熱可塑性樹脂フィルムを平板金型により挟んだ状態で加熱することを含む金型加熱工程を更に含むことが好ましい。金型加熱工程におけるプレス圧は、熱プレス工程におけるプレス圧よりも低いことが好ましい。より具体的には、例えば、熱プレス工程におけるプレス圧を１ＭＰａ以上１０ＭＰａ以下とした場合には、金型加熱工程におけるプレス圧は１ＭＰａ未満でありうる。そして、金型加熱工程は、熱可塑性樹脂フィルムと一対の平板金型の何れか一方とが接触する時点を始点として、プレス圧を熱プレス工程におけるプレス圧に切り替える時点を終点とする。金型加熱工程における所望のタイミングで平板金型への熱入力を開始して、上述した「熱プレス工程における一対の平板金型の温度」まで徐々に昇温させる。なお、金型加熱工程の終点より前のタイミング（例えば、金型加熱工程の終了時点の５０秒前の時点）で、昇温が完了していても良い。
　また、金型温度は、特に限定されることなく、既知の一般的な方法（例えば、既知のヒーター及びクーラー等を用いた温度制御方法）に従って、適宜調節することができる。 [Mold temperature]
The temperature of the pair of flat plate dies in the hot pressing step is preferably (Tg r +30) ° C. or higher, more preferably (Tg r +40) ° C. or higher, preferably (Tg r +70) ° C. or lower, and (Tg r +60) ° C. The following is more preferable. When the temperature of the pair of flat plate dies in the heat pressing step is equal to or higher than the above lower limit value, the occurrence of birefringence in the obtained transmission type optical element can be suppressed more satisfactorily. When the temperature of the pair of flat plate dies in the hot pressing process is equal to or lower than the above upper limit value, the transmission type optical element can be manufactured more efficiently.
In the heat pressing step, that is, in the operation process for pressing the thermoplastic resin film while heating it with a pair of flat plate dies, a predetermined press pressure is applied to the flat plate dies to press the thermoplastic resin film. Refers to the period of hot pressing. Here, it is preferable to further include a mold heating step including heating the thermoplastic resin film in a state of being sandwiched between the flat plate molds between the heat pressing step and the above-mentioned transporting step. The press pressure in the mold heating step is preferably lower than the press pressure in the hot press step. More specifically, for example, when the press pressure in the hot pressing step is 1 MPa or more and 10 MPa or less, the press pressure in the die heating step can be less than 1 MPa. The mold heating step starts at the time when the thermoplastic resin film and one of the pair of flat plate dies come into contact with each other, and ends at the time when the press pressure is switched to the press pressure in the hot press step. The heat input to the flat plate die is started at a desired timing in the mold heating step, and the temperature is gradually raised to the above-mentioned "temperature of a pair of flat plate dies in the hot pressing step". The temperature rise may be completed at a timing before the end point of the mold heating step (for example, 50 seconds before the end time of the mold heating step).
Further, the mold temperature is not particularly limited and can be appropriately adjusted according to a known general method (for example, a temperature control method using a known heater and cooler).
［金型材質］
　金型に用いる材質としては、公知の材質が使用できる。例えば、炭素鋼、ステンレス鋼、これらをベースにした合金類が挙げられ、なかでも加工性と硬度の観点から、ＳＴＡＶＡＸ（登録商標）材（ウッデホルム社製）等のステンレス鋼が好ましい。また、離型性の観点から、クロム、チタン、及びニッケル等の金属によるめっきが金型表面に施されてなる、金型を用いることが好ましく、なかでも、無電解ニッケル―リンめっきが金型表面に施されてなる金型を用いることが、より好ましい。 [Mold material]
As the material used for the mold, a known material can be used. For example, carbon steel, stainless steel, and alloys based on these are mentioned. Among them, stainless steel such as STAVAX (registered trademark) material (manufactured by Uddeholm) is preferable from the viewpoint of workability and hardness. From the viewpoint of mold releasability, it is preferable to use a mold in which the surface of the mold is plated with metals such as chromium, titanium, and nickel. Among them, electroless nickel-phosphorus plating is the mold. It is more preferable to use a mold formed on the surface.
＜＜その他の熱プレス条件＞＞
　なお、熱プレス工程におけるプレス圧力及びプレス時間は特に限定されることなく、用いる熱可塑性樹脂フィルムの種類及びサイズ、目的とする透過型光学素子の形状及び大きさ等に応じて、適宜決定することができる。例えば、プレス圧力は、１ＭＰａ以上１０ＭＰａ以下、プレス時間は１０秒以上１００秒以下とすることができる。なお、金型加熱工程におけるプレス圧は、例えば、１ＭＰａ未満であり得る。金型加熱工程の始点から終点までの所要時間は、１０秒以上１００秒以下とすることができる。 << Other heat press conditions >>
The pressing pressure and pressing time in the hot pressing step are not particularly limited, and are appropriately determined according to the type and size of the thermoplastic resin film to be used, the shape and size of the target transmissive optical element, and the like. Can be done. For example, the press pressure can be 1 MPa or more and 10 MPa or less, and the press time can be 10 seconds or more and 100 seconds or less. The press pressure in the die heating step can be, for example, less than 1 MPa. The time required from the start point to the end point of the mold heating step can be 10 seconds or more and 100 seconds or less.
＜金型冷却工程＞
　金型冷却工程では、一対の平板金型を熱可塑性樹脂フィルムのガラス転移温度（Ｔｇｒ）℃以下の温度まで冷却して、熱プレスフィルムを冷却する。かかる工程を実施することで、得られる透過型光学素子の形状精度を高めることができる。なお、金型冷却工程の始点は、例えば、熱プレス工程の開始時点から所定時間経過後に、平板金型について平板金型を冷却するための温度制御を開始する時点、或いは、熱プレス工程の開始時点から所定時間経過後に、平板金型に対する熱入力を停止した時点であり得る。金型冷却工程の終点は、後述する金型冷却温度まで金型温度が下がった時点、或いは、かかる時点から所定時間（例えば、５０秒）経過した時点であり得る。 <Mold cooling process>
The mold cooling process, to cool a pair of flat molds to the glass transition temperature (Tg r) ° C. below the temperature of the thermoplastic resin film, cooling the hot pressed film. By carrying out such a step, the shape accuracy of the obtained transmissive optical element can be improved. The starting point of the mold cooling process is, for example, the time when the temperature control for cooling the flat plate mold is started for the flat plate mold after a predetermined time has elapsed from the start time of the hot pressing process, or the start of the hot pressing process. It may be the time when the heat input to the flat plate mold is stopped after a predetermined time has elapsed from the time point. The end point of the mold cooling step may be a time when the mold temperature is lowered to the mold cooling temperature described later, or a time when a predetermined time (for example, 50 seconds) has elapsed from such a time.
＜＜金型冷却温度＞＞
　金型冷却温度は、熱可塑性樹脂フィルムのガラス転移温度（Ｔｇｒ）℃以下である必要があり、（Ｔｇｒ－１５）℃以下が好ましく、（Ｔｇｒ－３０）℃以下がより好ましく、（Ｔｇｒ－４０）℃以下が更に好ましい。また、金型冷却温度は、（Ｔｇｒ－８０）℃以上であることが好ましく、（Ｔｇｒ－７５）℃以上であることがより好ましい。金型冷却温度が上記上限値以下であれば、後述する離型工程にて、離型し易く、得られる透過型光学素子の形状精度を効果的に高めることができる。また、金型冷却温度が上記下限値以上であれば、透過型光学素子の製造効率を一層高めることができる。 << Mold cooling temperature >>
Mold cooling temperature must be at the glass transition temperature (Tg r) ° C. or less of the thermoplastic resin film, (Tg r -15) ° C. or less are preferred, (Tg r -30) ° C. and more preferably less, ( Tg r- 40) ° C. or lower is more preferable. Further, the mold cooling temperature is preferably (Tg r -80) is ° C. or higher, and more preferably (Tg r -75) ℃ or higher. When the mold cooling temperature is not more than the above upper limit value, it is easy to release the mold in the mold release step described later, and the shape accuracy of the obtained transmissive optical element can be effectively improved. Further, when the mold cooling temperature is equal to or higher than the above lower limit value, the manufacturing efficiency of the transmission type optical element can be further improved.
＜＜その他の金型冷却条件＞＞
　金型冷却時間及び金型冷却速度等は、特に限定されることなく、熱可塑性樹脂フィルムの種類及びサイズ、目的とする透過型光学素子の形状及び大きさ等に応じて、適宜決定することができる。例えば、金型冷却時間は、１０秒以上１００秒以下とすることができ、金型冷却速度は、５０℃／分以上３００℃／分以下とすることができる。 << Other mold cooling conditions >>
The mold cooling time, the mold cooling rate, etc. are not particularly limited, and may be appropriately determined according to the type and size of the thermoplastic resin film, the shape and size of the target transmissive optical element, and the like. it can. For example, the mold cooling time can be 10 seconds or more and 100 seconds or less, and the mold cooling rate can be 50 ° C./min or more and 300 ° C./min or less.
＜離型工程＞
　離型工程では、金型冷却工程の後に、熱プレスフィルムを一対の平板金型から離型するにあたり、熱プレスフィルムに対して張力をかけながら離型して、複数の透過型光学素子を含む成形フィルムを得る。「一対の平板金型から離型するにあたり」とは、金型冷却工程を完了させ、一対の平板金型を開き始める時点を意味する。かかる時点において、熱プレスフィルムに対して張力がかかった状態とすることによって、離型時に透過型光学素子の歪みが生じることを抑制して、得られる透過型光学素子の形状精度を高めることができる。ここで、張力は、搬送方向に沿う方向の力として作用させることが好ましい。また、離型工程における張力の制御方法は特に限定されず、公知の方法により制御することができる。例えば、熱プレスフィルムの巻き出しロール、熱プレスフィルムを巻き取るための巻取りロール、もしくは張力制御用に別途設けられたニップロール等により制御することができる。なお、巻き出しロール、巻取りロールを備えるロール・ツー・ロールの製造装置の例示的な構成については、図１を参照して後述する。
　さらに、離型工程のみならず、上述した熱プレス工程における、熱可塑性樹脂フィルムと一対の平板金型の何れか一方とが接触する金型加熱工程以降、離型工程を開始する時点までの各段階において、熱可塑性樹脂フィルムに対して継続的又は断続的に張力がかけられていることが好ましい。得られる透過型光学素子の形状精度を一層高めることができるからである。勿論、上記期間以外に行う他の工程においても、熱可塑性樹脂フィルムに対して張力がかけられていても良い。即ち、搬送工程から、離型工程以降に行い得る工程までの全ての工程を通じて、熱可塑性樹脂フィルムに対して張力がかけられていても良い。 <Release process>
In the mold release step, after the mold cooling step, when the hot press film is released from the pair of flat plate molds, the hot press film is released while applying tension to include a plurality of transmissive optical elements. Obtain a molded film. "When releasing from a pair of flat plate molds" means a time when the mold cooling process is completed and the pair of flat plate molds are started to be opened. At this point, by putting tension on the heat-pressed film, it is possible to suppress distortion of the transmissive optical element at the time of mold release and improve the shape accuracy of the obtained transmissive optical element. it can. Here, it is preferable that the tension acts as a force in the direction along the transport direction. Further, the method of controlling the tension in the mold release step is not particularly limited, and the tension can be controlled by a known method. For example, it can be controlled by a winding roll of the hot press film, a winding roll for winding the hot press film, a nip roll separately provided for tension control, or the like. An exemplary configuration of a roll-to-roll manufacturing apparatus including a take-up roll and a take-up roll will be described later with reference to FIG.
Further, not only in the mold removing step, but also in the above-mentioned heat pressing step, from the die heating step in which the thermoplastic resin film and one of the pair of flat plate dies come into contact with each other until the time when the mold removing step is started. It is preferable that the thermoplastic resin film is continuously or intermittently tensioned in the step. This is because the shape accuracy of the obtained transmissive optical element can be further improved. Of course, tension may be applied to the thermoplastic resin film in other steps other than the above period. That is, tension may be applied to the thermoplastic resin film through all the steps from the transfer step to the step that can be performed after the mold release step.
＜＜張力＞＞
　熱プレスフィルムに対して、搬送方向で作用させる張力の大きさは、熱可塑性樹脂フィルムの幅１ｍあたり、１Ｎ以上であることが好ましく、１０Ｎ以上であることがより好ましく、２０００Ｎ以下であることが好ましく、１０００Ｎ以下であることがより好ましい。なお、「熱可塑性樹脂フィルムの幅」とは、搬送方向に対して直交する方向である。張力の大きさが上記下限値以上であれば、得られる透過型光学素子の形状精度を一層高めることができる。また、張力の大きさが上記上限値以下であれば、熱プレスフィルムが破断することを抑制して、透過型光学素子の製造効率を一層高めることができる。 << Tension >>
The magnitude of the tension applied to the hot press film in the transport direction is preferably 1 N or more, more preferably 10 N or more, and more preferably 2000 N or less per 1 m of the width of the thermoplastic resin film. It is preferably 1000 N or less, and more preferably 1000 N or less. The "width of the thermoplastic resin film" is a direction orthogonal to the transport direction. When the magnitude of the tension is at least the above lower limit value, the shape accuracy of the obtained transmissive optical element can be further improved. Further, when the magnitude of the tension is not more than the above upper limit value, it is possible to suppress the hot press film from breaking and further improve the manufacturing efficiency of the transmissive optical element.
＜透過型光学素子分離工程＞
　透過型光学素子分離工程では、離型工程を経て得られた成形フィルムから、複数の透過型光学素子を分離する。成形フィルムから、複数の透過型光学素子を分離する透過型光学素子分離工程を実施することで、一層効率的に透過型光学素子を製造することができる。分離方法としては特に限定されることなく、抜き型による打ち抜き等の既知のあらゆる方法で、成形フィルムから、一つ一つの透過型光学素子を分離することができる。なお、透過型光学素子分離工程は、前段までの工程と同じ製造ライン上で、即ち、インラインで実施しても良い。或いは、透過型光学素子分離工程は、前段までの工程とは別の製造ライン上で、即ち、オフラインで実施しても良い。 <Transmission type optical element separation process>
In the transmission type optical element separation step, a plurality of transmission type optical elements are separated from the molded film obtained through the mold release step. By carrying out the transmission type optical element separation step of separating a plurality of transmission type optical elements from the molded film, the transmission type optical element can be manufactured more efficiently. The separation method is not particularly limited, and each transmissive optical element can be separated from the molded film by any known method such as punching with a punching die. The transmission optical element separation step may be carried out on the same production line as the steps up to the previous step, that is, in-line. Alternatively, the transmission type optical element separation step may be carried out on a production line different from the steps up to the previous step, that is, offline.
（透過型光学素子製造装置）
　図１は、本発明の一例に係る透過型光学素子の製造方法を実施するために用いることができる透過型光学素子製造装置の概略構造を示す図である。透過型光学素子製造装置１００は、一対の平板金型を構成する上部金型１Ａ及び下部金型１Ｂ、上部金型１Ａを支持するとともにこれを加熱及び冷却する上部温度調節装置２Ａ、上部温度調節装置２Ａを支持するとともにｚ軸方向に移動可能に構成されたｚ軸方向移動テーブル３、下部金型１Ｂを支持するとともにこれを加熱及び冷却する下部温度調節装置２Ｂ、及び下部温度調節装置２Ｂを支持する下部テーブル４を備える。さらに、透過型光学素子製造装置１００は熱可塑性樹脂フィルム７を送出するための構成部である巻き出しロール５Ａ及び成形フィルムを巻き取るための構成部である巻取りロール５Ｂを備え得る。さらにまた、透過型光学素子製造装置１００は、熱可塑性樹脂フィルム７の送出態様を制御するための構成部として、送りロール６を備えていても良い。なお、これらの各種構成部は、図示の態様に限定されるものではなく、上記したような各機能を発揮し得る限りにおいて、既存のあらゆる具体的手段により代替することが可能である。なお、図１において、透過型光学素子製造装置１００の鉛直方向をｚ軸、透過型光学素子製造装置１００のプレス面をｘｙ平面とする。また、図１に示す透過型光学素子製造装置１００は、所謂、「ロール・ツー・ロール」方式で樹脂フィルムから透過型光学素子を成形するための装置である。 (Transmissive optical element manufacturing equipment)
FIG. 1 is a diagram showing a schematic structure of a transmission type optical element manufacturing apparatus that can be used to carry out the method for manufacturing a transmission type optical element according to an example of the present invention. The transmission type optical element manufacturing apparatus 100 supports an upper mold 1A, a lower mold 1B, and an upper mold 1A constituting a pair of flat plate molds, and heats and cools the upper mold 2A and an upper temperature control device 2A. A z-axis direction moving table 3 that supports the device 2A and is configured to be movable in the z-axis direction, a lower temperature control device 2B that supports the lower mold 1B and heats and cools the lower mold 1B, and a lower temperature control device 2B. A lower table 4 to support is provided. Further, the transmission type optical element manufacturing apparatus 100 may include a take-up roll 5A which is a constituent part for delivering the thermoplastic resin film 7 and a take-up roll 5B which is a constituent part for winding the molded film. Furthermore, the transmission type optical element manufacturing apparatus 100 may include a feed roll 6 as a component for controlling the feed mode of the thermoplastic resin film 7. It should be noted that these various components are not limited to the illustrated mode, and can be replaced by any existing concrete means as long as they can exhibit the above-mentioned functions. In FIG. 1, the vertical direction of the transmission type optical element manufacturing apparatus 100 is the z-axis, and the press surface of the transmission type optical element manufacturing apparatus 100 is the xy plane. Further, the transmission type optical element manufacturing apparatus 100 shown in FIG. 1 is an apparatus for molding a transmission type optical element from a resin film by a so-called "roll-to-roll" method.
　以下、上述した本発明の透過型光学素子の製造方法に含まれうる各工程のうち、搬送工程（Ｓ０１）、金型加熱工程、熱プレス工程（Ｓ０２）、金型冷却工程（Ｓ０３）、離型工程（Ｓ０４）を、図１に示した透過型光学素子製造装置１００を用いて実施するものとして説明する。
　なお、上述した＜透過型光学素子分離工程＞は、図示しない打ち抜きユニット等を透過型光学素子製造装置１００に設けることにより、実施することができる。 Hereinafter, among the steps that can be included in the method for manufacturing the transmission type optical element of the present invention described above, the transfer step (S01), the die heating step, the hot pressing step (S02), the die cooling step (S03), and the release step. The mold process (S04) will be described as being carried out using the transmission type optical element manufacturing apparatus 100 shown in FIG.
The above-mentioned <transmission type optical element separation step> can be carried out by providing a punching unit or the like (not shown) in the transmission type optical element manufacturing apparatus 100.
　まず、本発明の透過型光学素子の製造方法を実施するための準備として、透過型光学素子製造装置１００の巻き出しロール５Ａ、巻取りロール５Ｂ、及び送りロール６に熱可塑性樹脂フィルム７をセットする。そして、搬送工程（Ｓ０１）において、金型加熱工程及び熱プレス工程（Ｓ０２）に先立って、熱可塑性樹脂フィルム７を、所定の搬送方向に沿って搬送する。なお、図１において、搬送方向は矢印１０で示す方向である。 First, as a preparation for carrying out the method for manufacturing a transmissive optical element of the present invention, the thermoplastic resin film 7 is set on the unwinding roll 5A, the winding roll 5B, and the feed roll 6 of the transmissive optical element manufacturing apparatus 100. To do. Then, in the transfer step (S01), the thermoplastic resin film 7 is conveyed along a predetermined transfer direction prior to the die heating step and the heat pressing step (S02). In FIG. 1, the transport direction is the direction indicated by the arrow 10.
　金型加熱工程及び熱プレス工程（Ｓ０２）を行う際には、上部金型１Ａ及び下部金型１Ｂにより、熱可塑性樹脂フィルム７を熱プレスする。なお、熱プレス工程等に際して、熱可塑性樹脂フィルム７のｚ軸方向における位置も、適宜調節することが可能である。なお、搬送工程（Ｓ０１）と熱プレス工程（Ｓ０２）との間のタイミングにて実施されうる金型加熱工程では、金型加熱工程の開始時点、即ち、上部金型１Ａ及び下部金型１Ｂの少なくとも一方と熱可塑性樹脂フィルム７とが接触する時点の後、熱プレス工程（Ｓ０２）の開始時点（所定のプレス圧の印加を開始する時点）までに、上部金型１Ａ及び下部金型１Ｂの温度を、上部温度調節装置２Ａ及び下部温度調節装置２Ｂにより、上述した所定の温度範囲とする。 When performing the die heating step and the hot pressing step (S02), the thermoplastic resin film 7 is hot pressed by the upper die 1A and the lower die 1B. The position of the thermoplastic resin film 7 in the z-axis direction can also be appropriately adjusted during the heat pressing step or the like. In the die heating step that can be performed at the timing between the transfer step (S01) and the hot pressing step (S02), the start time of the die heating step, that is, the upper die 1A and the lower die 1B After the time when at least one of them comes into contact with the thermoplastic resin film 7, by the time when the hot pressing step (S02) is started (when the application of a predetermined pressing pressure is started), the upper dies 1A and the lower dies 1B The temperature is set to the above-mentioned predetermined temperature range by the upper temperature control device 2A and the lower temperature control device 2B.
　金型冷却工程（Ｓ０３）にあたり、上部温度調節装置２Ａ及び下部温度調節装置２Ｂにより、上部金型１Ａ及び下部金型１Ｂの温度を、熱可塑性樹脂フィルム７のガラス転移温度（Ｔｇｒ）℃以下の温度とすることが好ましい。 Per the mold cooling step (S03), by the upper temperature adjusting unit 2A and the lower temperature adjusting apparatus 2B, the temperature of the upper mold 1A and a lower mold 1B, the glass transition temperature of the thermoplastic resin film 7 (Tg r) ℃ or less It is preferable to set the temperature to.
　そして、離型工程（Ｓ０４）にあたり、熱プレスフィルムとしての熱可塑性樹脂フィルム７に対して張力をかけつつ、熱可塑性樹脂フィルム７を平板金型から離型する。このとき、張力は、例えば、巻き出しロール５Ａ、巻取りロール５Ｂ、及び送りロール６を用いて負荷及び調節することができる。 Then, in the mold release step (S04), the thermoplastic resin film 7 is released from the flat plate mold while applying tension to the thermoplastic resin film 7 as the hot press film. At this time, the tension can be loaded and adjusted using, for example, a take-up roll 5A, a take-up roll 5B, and a feed roll 6.
（透過型光学素子の製造例の概略）
　図２及び図３を参照して、本発明の透過型光学素子の製造方法により透過型光学素子としての光学レンズを製造する場合について、説明する。図１と同じ参照符号を付した構成については、図１に関連して説明した通りである。図２及び図３では、それぞれ、異なる形状の光学レンズを製造しているため、平板金型の形状は異なる。このため、図２では、上部金型１Ａ’及び下部金型１Ｂ’と示し、図３では上部金型１Ａ”及び下部金型１Ｂ”として示す。また、得られる光学レンズの形状も異なるため、図２では得られる光学レンズを光学レンズ８’と示し、図３では得られる光学レンズを光学レンズ８”として示す。
　なお、図２及び図３は、搬送方向から見た断面図であり、熱可塑性樹脂フィルム７、上部金型１Ａ’及び下部金型１Ｂ’、上部金型１Ａ”及び下部金型１Ｂ”、並びに、光学レンズ８’及び８”は、それぞれ一部のみを示す。 (Outline of manufacturing example of transmissive optical element)
A case where an optical lens as a transmission type optical element is manufactured by the method for manufacturing a transmission type optical element of the present invention will be described with reference to FIGS. 2 and 3. The configuration with the same reference numerals as those in FIG. 1 is as described in relation to FIG. In FIGS. 2 and 3, since the optical lenses having different shapes are manufactured, the shapes of the flat plate molds are different. Therefore, in FIG. 2, it is shown as an upper mold 1A'and a lower mold 1B', and in FIG. 3, it is shown as an upper mold 1A "and a lower mold 1B". Further, since the shapes of the obtained optical lenses are also different, the obtained optical lens is shown as an optical lens 8'in FIG. 2, and the obtained optical lens is shown as an optical lens 8'in FIG.
2 and 3 are cross-sectional views seen from the transport direction, and are a thermoplastic resin film 7, an upper mold 1A'and a lower mold 1B', an upper mold 1A "and a lower mold 1B", and , Optical lenses 8'and 8 "show only a part, respectively.
　図２に示すように、図示しない搬送工程（Ｓ０１）を経て搬送された熱可塑性樹脂フィルム７を、熱プレス工程（Ｓ０２）にて、一対の平板金型としての上部金型１Ａ’及び下部金型１Ｂ’により熱プレスして、熱可塑性樹脂フィルム７を熱により溶融又は変形させて平板金型内に熱可塑性樹脂を充填する。上部金型１Ａ’及び下部金型１Ｂ’は、金型加熱工程及び熱プレス工程（Ｓ０２）では図示しない部分において相互に接触している。熱プレス工程（Ｓ０２）にて、熱可塑性樹脂フィルム７の最薄部の厚みがＤminとなる。そして、金型冷却工程（Ｓ０３）にて上部金型１Ａ’及び下部金型１Ｂ’を冷却する。さらに、離型工程（Ｓ０４）にて上部金型１Ａ’及び下部金型１Ｂ’より成形フィルムとしての熱可塑性樹脂フィルム７を離型する。そして、透過型光学素子分離工程（Ｓ０５）にて破線で示す切断線に沿って成形フィルムとしての熱可塑性樹脂フィルム７を切断して、複数の光学レンズ８’を得る。 As shown in FIG. 2, the thermoplastic resin film 7 transported through a transport step (S01) (not shown) is subjected to a heat pressing step (S02) to form an upper die 1A'and a lower die as a pair of flat plate dies. The thermoplastic resin film 7 is melted or deformed by heat by hot pressing with the mold 1B', and the thermoplastic resin is filled in the flat plate die. The upper mold 1A'and the lower mold 1B' are in contact with each other in a portion (not shown) in the mold heating step and the heat pressing step (S02). In the heat pressing step (S02), the thickness of the thinnest portion of the thermoplastic resin film 7 becomes D min . Then, the upper mold 1A'and the lower mold 1B' are cooled in the mold cooling step (S03). Further, in the mold release step (S04), the thermoplastic resin film 7 as a molding film is released from the upper mold 1A'and the lower mold 1B'. Then, in the transmission type optical element separation step (S05), the thermoplastic resin film 7 as a molding film is cut along the cutting line indicated by the broken line to obtain a plurality of optical lenses 8'.
　図３については、上部金型１Ａ”及び下部金型１Ｂ”の形状を異なるものとし、図２を参照して説明した一例とは異なる形状の複数の光学レンズ８”を得た以外は、図２と同様である。 Regarding FIG. 3, except that the shapes of the upper mold 1A ”and the lower mold 1B” are different, and a plurality of optical lenses 8 ”are different in shape from the example described with reference to FIG. 2 are obtained. It is the same as 2.
（透過型光学素子）
　本発明の透過型光学素子の製造方法により得られる透過型光学素子としての光学レンズは、低複屈折性であるとともに、且つ、形状精度が高いものである。例えば、本発明の透過型光学素子の製造方法により得られる透過型光学素子としての光学レンズは、光学有効径内の位相差が、１００ｎｍ以下であることが好ましく、５０ｎｍ以下であることがより好ましく、２０ｎｍ以下であることがさらに好ましい。光学有効系内の位相差が１００ｎｍである光学レンズは、十分に低複屈折性である光学レンズである。なお、本発明において、位相差の値は、実施例に記載の方法に従って求めることができる。
　本発明の透過型光学素子の製造方法により得られる透過型光学素子は、設計上の光学面の形状を基準とした場合の、製造した透過型光学素子の光学面形状の最大誤差、即ち、ＰＶ（Ｐｅａｋ ｔｏ Ｖａｌｌｅｙ）値が、１．０μｍ以下であることが好ましく、０．６μｍ以下であることがより好ましく、０．４μｍ以下であることがさらに好ましい。ＰＶ値の値が１．０μｍ以下である透過型光学素子は、形状精度が充分に高い透過型光学素子である。 (Transmissive optical element)
The optical lens as a transmissive optical element obtained by the method for manufacturing a transmissive optical element of the present invention has low birefringence and high shape accuracy. For example, the optical lens as a transmissive optical element obtained by the method for manufacturing a transmissive optical element of the present invention preferably has a phase difference within the optical effective diameter of 100 nm or less, more preferably 50 nm or less. , 20 nm or less is more preferable. An optical lens having a phase difference of 100 nm in an optically effective system is an optical lens having sufficiently low birefringence. In the present invention, the value of the phase difference can be obtained according to the method described in Examples.
The transmissive optical element obtained by the method for manufacturing a transmissive optical element of the present invention has a maximum error in the optical surface shape of the manufactured transmissive optical element, that is, PV when the shape of the optical surface in design is used as a reference. The (Peek to Valley) value is preferably 1.0 μm or less, more preferably 0.6 μm or less, and further preferably 0.4 μm or less. A transmissive optical element having a PV value of 1.0 μm or less is a transmissive optical element having sufficiently high shape accuracy.
　以下、実施例及び比較例を挙げて、本発明をさらに詳細に説明する。なお、本発明はこれらの例に何ら限定されるものではない。実施例及び比較例において、熱可塑性樹脂フィルムの厚み、厚みばらつき及びガラス転移温度は以下のようにして測定した。また、実施例及び比較例において、形状精度平均値、形状精度ばらつき、位相差、形状良品率を考慮した製造効率、並びに、形状及び低複屈折性を考慮した製造効率は、以下のようにして算出及び評価した。
　なお、実施例１～１４、及び比較例２～３では、離型時の張力を所望の値に調節するにあたり、図１に示した概略構成に従う製造装置に備えられた巻き出しロール及び巻き取りロール等を張力コントローラーで制御した。表１に制御値を示す。なお、表１に示す張力の値は、熱可塑性樹脂フィルムの幅１ｍあたりの値である。また、張力の方向は、搬送方向に沿う方向とした。
　また、実施例及び比較例では、透過型光学素子として光学レンズ（両凸レンズ又は凸メニスカスレンズ）を製造した。 Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to these examples. In Examples and Comparative Examples, the thickness, thickness variation, and glass transition temperature of the thermoplastic resin film were measured as follows. Further, in Examples and Comparative Examples, the manufacturing efficiency considering the shape accuracy average value, the shape accuracy variation, the phase difference, and the shape non-defective rate, and the manufacturing efficiency considering the shape and low birefringence are as follows. Calculated and evaluated.
In Examples 1 to 14 and Comparative Examples 2 to 3, in order to adjust the tension at the time of mold release to a desired value, the unwinding roll and winding provided in the manufacturing apparatus according to the schematic configuration shown in FIG. The roll etc. were controlled by the tension controller. Table 1 shows the control values. The tension values shown in Table 1 are values per 1 m of width of the thermoplastic resin film. The direction of tension was set along the transport direction.
Further, in Examples and Comparative Examples, an optical lens (biconvex lens or convex meniscus lens) was manufactured as a transmissive optical element.
＜熱可塑性樹脂フィルムの厚み＞
　熱可塑性樹脂フィルムの任意箇所で２５０ｍｍ長に３枚を切り出し、切り出した各サンプルの長手方向、幅方向それぞれの中央部で２０ｍｍ間隔に１１×１１か所で厚さを測定し、熱可塑性樹脂フィルムの最大厚み及び最小厚みを得た。熱可塑性樹脂フィルムの厚みはこれらの平均値とした。また、熱可塑性樹脂フィルムの厚みばらつきは、最大厚み及び最小厚みの差分とした。 <Thickness of thermoplastic resin film>
Three sheets were cut out to a length of 250 mm at arbitrary points of the thermoplastic resin film, and the thickness was measured at 11 × 11 points at intervals of 20 mm at the center of each of the cut out samples in the longitudinal direction and the width direction, and the thermoplastic resin film was formed. The maximum thickness and the minimum thickness of were obtained. The thickness of the thermoplastic resin film was taken as the average value of these. Further, the thickness variation of the thermoplastic resin film was defined as the difference between the maximum thickness and the minimum thickness.
＜熱可塑性樹脂フィルムのガラス転移温度＞
　実施例、比較例で用いた熱可塑性樹脂フィルムのガラス転移温度（Ｔｇ）は、示差走査熱量分析計（ＳＩＩナノテクノロジー社製、「ＤＳＣ６２２０」）を用いて、ＪＩＳ Ｋ７１２１に基づき昇温速度１０℃／分の条件で測定した。 <Glass transition temperature of thermoplastic resin film>
The glass transition temperature (Tg) of the thermoplastic resin film used in Examples and Comparative Examples was measured at a heating rate of 10 ° C. based on JIS K7121 using a differential scanning calorimeter (“DSC6220” manufactured by SII Nanotechnology). It was measured under the condition of / minute.
＜形状精度平均値及び形状精度ばらつき＞
　実施例及び比較例で得られた測定試料である光学レンズの形状精度を、形状測定器（三鷹光機社製、「ＮＨ－３ＳＰ」）を用いて、設計上の光学表面を基準表面とするＰＶ値として測定した。測定したＰＶ値の単純平均値を形状精度平均値とし、標準偏差を形状精度ばらつきとした。
　実施例１～１４、比較例１～２では、測定試料である光学レンズとして、同じ熱プレス工程で得られた３９６個の光学レンズのそれぞれについてＰＶ値を測定した。また、比較例３では、エンボスロール一周分の成形物である４１４個の光学レンズのそれぞれについてＰＶ値を測定した。さらにまた、比較例４では、１６個取り金型を用いて１０回の製造工程を行って得た１６０個の光学レンズのそれぞれについてＰＶ値を測定した。
［形状精度平均値の評価基準］
　得られた形状精度平均値の値は、以下の基準に従って評価した。
　Ａ：０．４μｍ以下
　Ｂ：０．４μｍ超０．６μｍ以下
　Ｃ：０．６μｍ超１．０μｍ以下
　Ｄ：１．０μｍ超
［形状精度ばらつきの評価基準］
　また、得られた形状精度ばらつきの値は、以下の基準に従って評価した。
　Ａ：０．１μｍ以内
　Ｂ：０．１μｍ超０．２μｍ以内
　Ｃ：０．２μｍ超０．３μｍ以内
　Ｄ：０．３μｍ超 <Average shape accuracy and variation in shape accuracy>
The shape accuracy of the optical lens, which is the measurement sample obtained in the examples and comparative examples, is measured using a shape measuring instrument (manufactured by Mitaka Kohki Co., Ltd., "NH-3SP") with the designed optical surface as the reference surface. It was measured as a PV value. The simple average value of the measured PV values was defined as the shape accuracy average value, and the standard deviation was defined as the shape accuracy variation.
In Examples 1 to 14 and Comparative Examples 1 and 2, PV values were measured for each of the 396 optical lenses obtained in the same heat pressing step as the optical lenses as measurement samples. Further, in Comparative Example 3, the PV value was measured for each of the 414 optical lenses, which are molded products for one round of the embossed roll. Furthermore, in Comparative Example 4, PV values were measured for each of the 160 optical lenses obtained by performing 10 manufacturing steps using a 16-piece die.
[Evaluation criteria for average shape accuracy]
The value of the obtained shape accuracy average value was evaluated according to the following criteria.
A: 0.4 μm or less B: 0.4 μm or more 0.6 μm or less C: 0.6 μm or more 1.0 μm or less D: 1.0 μm or more [Evaluation criteria for shape accuracy variation]
Moreover, the value of the obtained shape accuracy variation was evaluated according to the following criteria.
A: Within 0.1 μm B: Over 0.1 μm Within 0.2 μm C: Over 0.2 μm Within 0.3 μm D: Over 0.3 μm
＜位相差＞
　測定試料である光学レンズの有効径内の位相差を、樹脂成形レンズ検査システム〔「ＷＰＡ－１００」、フォトニックスラティス社製〕を用いて測定した。位相差の値は、測定波長（５４３ｎｍ）で規格化した値として得られる。位相差の値は、複数の測定試料について測定して得た値の単純平均値とした。
　各実施例、比較例における測定試料としては、＜形状精度平均値及び形状精度ばらつき＞の項目に記載したものと同じものを用いた。
　得られた位相差の値を、以下の基準に従って評価した。位相差の値が小さいほど、複屈折が小さいことを意味する。
　Ａ：２０ｎｍ以下
　Ｂ：２０ｎｍ超５０ｎｍ以下
　Ｃ：５０ｎｍ超１００ｎｍ以下
　Ｄ：１００ｎｍ超 <Phase difference>
The phase difference within the effective diameter of the optical lens as the measurement sample was measured using a resin molded lens inspection system [“WPA-100”, manufactured by Photonics Lattice). The phase difference value is obtained as a value standardized at the measurement wavelength (543 nm). The value of the phase difference was a simple average value of the values obtained by measuring a plurality of measurement samples.
As the measurement samples in each Example and Comparative Example, the same samples as those described in the items of <Average shape accuracy value and variation in shape accuracy> were used.
The obtained phase difference values were evaluated according to the following criteria. The smaller the phase difference value, the smaller the birefringence.
A: 20 nm or less B: 20 nm or more and 50 nm or less C: 50 nm or more and 100 nm or less D: 100 nm or less
＜形状及び低複屈折性を考慮した製造効率＞
　＜形状精度平均値及び形状精度ばらつき＞及び＜位相差＞の項目にて説明した方法と同様にして、各測定試料についてＰＶ値及び位相差を測定し、ＰＶ値が１．０μｍ以下であり、且つ、位相差が１００ｎｍ以下であり、外周部に亀裂が無い測定試料を「形状精度が高く且つ低複屈折性である光学レンズＡ」とした。かかる光学レンズＡの個数を、各実施例、比較例で用いた全測定試料を製造するために要した時間（サイクルタイム；分）で除して、１分当たりの光学レンズＡの個数を算出した。
　また、全測定試料に占める上記光学レンズＡの比率をそれぞれ算出した。 <Manufacturing efficiency considering shape and low birefringence>
The PV value and the phase difference were measured for each measurement sample in the same manner as described in the items of <Average value of shape accuracy and variation in shape accuracy> and <Phase difference>, and the PV value was 1.0 μm or less. A measurement sample having a phase difference of 100 nm or less and no cracks on the outer peripheral portion was designated as "optical lens A having high shape accuracy and low double refractive index". The number of optical lenses A per minute is calculated by dividing the number of such optical lenses A by the time (cycle time; minutes) required to produce all the measurement samples used in each Example and Comparative Example. did.
In addition, the ratio of the optical lens A to all the measurement samples was calculated.
（実施例１）
　ノルボルネン系開環重合体水素化物を含む熱可塑性樹脂（ＺＥＯＮＥＸ Ｅ４８Ｒ（日本ゼオン社製）、ガラス転移温度：１３９℃）を、フィルム押出成形機（単軸押出機、φ＝２０ｍｍ、ＧＳＩクレオス社製）に入れ、これを２６０℃で溶融し、溶融樹脂をＴダイから押し出し、これを冷却して、最大厚みが２０２μｍ、最小厚みが１９８μｍ、厚みばらつきが４μｍである、幅２８０ｍｍの熱可塑性樹脂フィルムを得た。なお、熱可塑性フィルムの幅方向に垂直な方向が長手方向となっており、ロール・ツー・ロール成形法により成形するために充分な長さを有していた。 (Example 1)
A thermoplastic resin containing a norbornene-based ring-opening polymer hydride (ZEONEX E48R (manufactured by Nippon Zeon), glass transition temperature: 139 ° C.) is used in a film extruder (single-screw extruder, φ = 20 mm, manufactured by GSI Creos). ), This is melted at 260 ° C., the molten resin is extruded from the T-die, and this is cooled to obtain a thermoplastic resin film having a maximum thickness of 202 μm, a minimum thickness of 198 μm, and a thickness variation of 4 μm, and a width of 280 mm. Got The direction perpendicular to the width direction of the thermoplastic film is the longitudinal direction, and has a sufficient length for molding by the roll-to-roll molding method.
　上記に従って得られた熱可塑性樹脂フィルムを図１示した概略構成に従う製造装置にセットした。なお、一対の平板金型としては、金型一枚あたり、直径が３．２ｍｍである光学面（即ち、レンズ面）形成領域を３９６個有するもの（個数密度：０．６３個／ｃｍ２）を用いた。平板金型に含まれる光学面形成部の直径は３．２ｍｍであり、光学面形成領域間の最小間隔は１０ｍｍであり、最浅部の深さの合計（Ｄmin）は１５０μｍであり、光学面形成領域における最深部の深さの合計（Ｄmax）は５５０μｍであった。かかる一対の平板金型により得られる光学レンズは、両凸レンズである。本例では、搬送工程～離型工程までの全工程にて、熱プレスフィルムに対して搬送方向に張力をかけた。 The thermoplastic resin film obtained according to the above was set in a manufacturing apparatus according to the schematic configuration shown in FIG. The pair of flat plate molds has 396 optical surface (that is, lens surface) forming regions having a diameter of 3.2 mm per mold (number density: 0.63 / cm 2 ). Was used. The diameter of the optical surface forming portion included in the flat plate mold is 3.2 mm, the minimum distance between the optical surface forming regions is 10 mm, the total depth of the shallowest portions (D min ) is 150 μm, and the optical The total depth (D max ) of the deepest part in the surface forming region was 550 μm. The optical lens obtained by such a pair of flat plate molds is a biconvex lens. In this example, tension was applied to the hot press film in the transport direction in all steps from the transport step to the mold release step.
　光学レンズの製造にあたり、搬送工程を実施して、熱可塑性樹脂フィルムを所定位置までフィルムの長手方向に沿う搬送方向に搬送した。そして、未加熱の状態（８０℃以下）の上記一対の平板金型により熱可塑性樹脂フィルムを挟み込み（プレス圧：０．５ＭＰａ）、その状態を維持したまま、１９０℃（プレス温度、熱可塑性樹脂フィルムのガラス転移温度Ｔｇｒ＋５１℃）まで平板金型を加熱した（金型加熱工程）。そして、一対の平板金型を用いてプレス圧６ＭＰａで熱可塑性樹脂フィルムを熱プレスして、熱プレスフィルムを得た（熱プレス工程）。さらに、熱プレスフィルムをプレスしたままの状態で、一対の平板金型を８０℃（熱可塑性樹脂フィルムのガラス転移温度Ｔｇｒ－５９℃）まで、４０秒間かけて冷却して、金型間に挟まれた状態の熱プレスフィルムを冷却した（金型冷却工程）。その後、平板金型を開いて金型冷却工程を終了し、離型工程を開始した。そして、離型工程を経て得られた複数の光学レンズを含む成形フィルムについて、内径８ｍｍの丸刃での打ち抜きによる分離工程を実施して、３９６枚の光学レンズを得た。離型工程にて熱プレスフィルムに対してかけられた張力の大きさは、熱可塑性樹脂フィルムの幅１ｍあたり１００Ｎ（１００Ｎ／ｍ）であった。搬送工程を開始してから離型工程を完了するまでに要した時間（サイクルタイム）は、１８０秒であった。得られた光学レンズについて、上記に従って各種測定及び評価を行った。結果を表１に示す。 In manufacturing the optical lens, a transport process was carried out to transport the thermoplastic resin film to a predetermined position in the transport direction along the longitudinal direction of the film. Then, the thermoplastic resin film is sandwiched between the pair of flat plate dies in an unheated state (80 ° C. or lower) (press pressure: 0.5 MPa), and while maintaining that state, 190 ° C. (press temperature, thermoplastic resin). the glass transition temperature Tg r + 51 ° C.) until flat die film was heated (mold heating step). Then, the thermoplastic resin film was hot-pressed at a press pressure of 6 MPa using a pair of flat plate dies to obtain a hot-press film (heat-pressing step). Further, the hot press film in a state in which the press, 80 ° C. a pair of flat dies to (glass transition temperature Tg r -59 ° C. for the thermoplastic resin film), and cooled over a period of 40 seconds, between the dies The hot press film in the sandwiched state was cooled (die cooling step). After that, the flat plate mold was opened, the mold cooling process was completed, and the mold release process was started. Then, the molded film containing the plurality of optical lenses obtained through the mold release step was separated by punching with a round blade having an inner diameter of 8 mm to obtain 396 optical lenses. The magnitude of the tension applied to the hot press film in the mold release step was 100 N (100 N / m) per 1 m of the width of the thermoplastic resin film. The time (cycle time) required from the start of the transfer process to the completion of the mold release process was 180 seconds. The obtained optical lens was subjected to various measurements and evaluations according to the above. The results are shown in Table 1.
（実施例２）
　熱可塑性樹脂フィルムに対してかける張力を、表１に示す通りに変更した以外は、実施例１と同様にして、光学レンズを製造した。そして、実施例１と同様の各種測定及び評価を行った。結果を表１に示す。 (Example 2)
An optical lens was manufactured in the same manner as in Example 1 except that the tension applied to the thermoplastic resin film was changed as shown in Table 1. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 1.
（実施例３）
　金型加熱工程、熱プレス工程、及び金型冷却工程で熱可塑性樹脂フィルムに対して張力がかからないようにした以外は、実施例２と同様にして、光学レンズを製造した。そして、実施例１と同様の各種測定及び評価を行った。結果を表１に示す。なお、金型加熱工程、熱プレス工程、及び金型冷却工程以外の工程（即ち、搬送工程及び離型工程）では、実施例２と同様に、熱可塑性樹脂フィルムに対して張力がかかった状態となっていた。 (Example 3)
An optical lens was manufactured in the same manner as in Example 2 except that tension was not applied to the thermoplastic resin film in the mold heating step, the hot pressing step, and the mold cooling step. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 1. In steps other than the die heating step, the hot pressing step, and the die cooling step (that is, the transfer step and the mold release step), a state in which tension is applied to the thermoplastic resin film as in Example 2. It was.
（実施例４～５）
　離型工程にて熱プレスフィルムに対してかける張力の大きさ、熱可塑性樹脂フィルムの厚み、並びに、熱プレス工程で用いる平板金型の最浅部の深さの合計（Ｄmin）及び最深部の深さの合計（Ｄmax）を表１に示す通りに変更した。これらの点以外は実施例１と同様にして、光学レンズを製造した。そして、実施例１と同様の各種測定及び評価を行った。結果を表１に示す。なお、実施例４及び５では、離型工程以降の段階で、熱可塑性樹脂フィルムに若干の破断が生じ製造効率が低下した。 (Examples 4 to 5)
The magnitude of the tension applied to the hot press film in the mold release process, the thickness of the thermoplastic resin film, and the total depth (D min ) and the deepest part of the shallowest part of the flat plate mold used in the hot press process. The total depth (D max ) of was changed as shown in Table 1. An optical lens was manufactured in the same manner as in Example 1 except for these points. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 1. In Examples 4 and 5, the thermoplastic resin film was slightly broken at the stage after the mold release step, and the production efficiency was lowered.
（実施例６）
　熱プレス工程における平板金型の温度（プレス温度）を表１に示す通りに変更した以外は、実施例１と同様にして、光学レンズを製造した。そして、実施例１と同様の各種測定及び評価を行った。結果を表１に示す。 (Example 6)
An optical lens was manufactured in the same manner as in Example 1 except that the temperature of the flat plate die (pressing temperature) in the hot pressing step was changed as shown in Table 1. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 1.
（実施例７～８）
　熱プレス工程における平板金型の温度（プレス温度）及び金型冷却工程における平板金型の冷却温度を表１に示す通りにそれぞれ変更した以外は、実施例１と同様にして、光学レンズを製造した。そして、実施例１と同様の各種測定及び評価を行った。結果を表１に示す。 (Examples 7 to 8)
An optical lens is manufactured in the same manner as in Example 1 except that the temperature of the flat plate die (pressing temperature) in the hot pressing process and the cooling temperature of the flat plate mold in the mold cooling process are changed as shown in Table 1. did. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 1.
（実施例９）
　以下のようにして調製した熱可塑性樹脂フィルムを用いた以外は実施例１と同様にして、光学レンズを製造した。そして、実施例１と同様にして各種測定及び評価を行った。結果を表１に示す。
＜熱可塑性樹脂フィルムの調製＞
　ノルボルネンとエチレンとをモノマーとして用いたランダム付加重合により得られたノルボルネン－エチレンランダム共重合体を含む熱可塑性樹脂（ＴＯＰＡＳ６０１３（Ｐｏｌｙｐｌａｓｔｉｃｓ社製）、ガラス転移温度：１３８℃）を、フィルム押出成形機（単軸押出機、φ＝２０ｍｍ、ＧＳＩクレオス社製）に入れ、２６０℃で溶融し、溶融樹脂をＴダイから押し出し、冷却して、最大厚みが２０２μｍ、最小厚みが１９８μｍ、厚みばらつきが４μｍである、幅２８０ｍｍの熱可塑性樹脂フィルムを得た。なお、熱可塑性フィルムの幅方向に垂直な方向が長手方向となっており、ロール・ツー・ロール成形法により成形するために充分な長さを有していた。 (Example 9)
An optical lens was produced in the same manner as in Example 1 except that the thermoplastic resin film prepared as follows was used. Then, various measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.
<Preparation of thermoplastic resin film>
A thermoplastic resin (TOPAS6013 (manufactured by Polyplastics), glass transition temperature: 138 ° C.) containing a norbornene-ethylene random copolymer obtained by random addition polymerization using norbornene and ethylene as monomers was used in a film extruder (). Put in a single-screw extruder, φ = 20 mm, manufactured by GSI Creos), melt at 260 ° C., extrude the molten resin from the T die, cool it, and have a maximum thickness of 202 μm, a minimum thickness of 198 μm, and a thickness variation of 4 μm. A thermoplastic resin film having a width of 280 mm was obtained. The direction perpendicular to the width direction of the thermoplastic film is the longitudinal direction, and has a sufficient length for molding by the roll-to-roll molding method.
（実施例１０）
　以下のようにして調製した熱可塑性樹脂フィルムを用いた以外は実施例１と同様にして、光学レンズを製造した。そして、実施例１と同様にして各種測定及び評価を行った。結果を表１に示す。
＜熱可塑性樹脂フィルムの調製＞
　ポリカーボネート樹脂（ワンダーライトＰＣ－１１５（旭化成社製）、ガラス転移温度：１４５℃）を、フィルム押出成形機（単軸押出機、φ＝２０ｍｍ、ＧＳＩクレオス社製）に入れ、２７５℃で溶融し、溶融樹脂をＴダイから押し出し、冷却して、最大厚みが２０２μｍ、最小厚みが１９８μｍ、厚みばらつきが４μｍである、幅２８０ｍｍの熱可塑性樹脂フィルムを得た。なお、熱可塑性フィルムの幅方向に垂直な方向が長手方向となっており、ロール・ツー・ロール成形法により成形するために充分な長さを有していた。 (Example 10)
An optical lens was produced in the same manner as in Example 1 except that the thermoplastic resin film prepared as follows was used. Then, various measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.
<Preparation of thermoplastic resin film>
Polycarbonate resin (Wonderlight PC-115 (manufactured by Asahi Kasei Co., Ltd.), glass transition temperature: 145 ° C.) was placed in a film extruder (single-screw extruder, φ = 20 mm, manufactured by GSI Creos Co., Ltd.) and melted at 275 ° C. The molten resin was extruded from the T-die and cooled to obtain a thermoplastic resin film having a width of 280 mm, a maximum thickness of 202 μm, a minimum thickness of 198 μm, and a thickness variation of 4 μm. The direction perpendicular to the width direction of the thermoplastic film is the longitudinal direction, and has a sufficient length for molding by the roll-to-roll molding method.
（実施例１１）
　以下のようにして調製した熱可塑性樹脂フィルムを用いたことと、熱プレス工程における平板金型の温度（プレス温度）及び金型冷却工程における平板金型の冷却温度を表１に示す通りに変更したこと以外は実施例１と同様にして、光学レンズを製造した。そして、実施例１と同様にして各種測定及び評価を行った。結果を表１に示す。
＜熱可塑性樹脂フィルムの調製＞
　ポリメチルメタクリレート樹脂（デルペット８０ＮＨ（旭化成ケミカルズ社製）、ガラス転移温度：１００℃）を、フィルム押出成形機（単軸押出機、φ＝２０ｍｍ、ＧＳＩクレオス社製）に入れ、２５０℃で溶融し、溶融樹脂をＴダイから押し出し、冷却して、最大厚みが２０２μｍ、最小厚みが１９８μｍ、厚みばらつきが４μｍである、幅２８０ｍｍの熱可塑性樹脂フィルムを得た。なお、熱可塑性フィルムの幅方向に垂直な方向が長手方向となっており、ロール・ツー・ロール成形法により成形するために充分な長さを有していた。 (Example 11)
Using the thermoplastic resin film prepared as follows, the temperature of the flat plate mold in the hot pressing process (pressing temperature) and the cooling temperature of the flat plate mold in the mold cooling process were changed as shown in Table 1. An optical lens was manufactured in the same manner as in Example 1 except for the above. Then, various measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.
<Preparation of thermoplastic resin film>
Polymethylmethacrylate resin (Delpet 80NH (manufactured by Asahi Kasei Chemicals), glass transition temperature: 100 ° C) is placed in a film extruder (single-screw extruder, φ = 20 mm, manufactured by GSI Creos) and melted at 250 ° C. Then, the molten resin was extruded from the T-die and cooled to obtain a thermoplastic resin film having a width of 280 mm, a maximum thickness of 202 μm, a minimum thickness of 198 μm, and a thickness variation of 4 μm. The direction perpendicular to the width direction of the thermoplastic film is the longitudinal direction, and has a sufficient length for molding by the roll-to-roll molding method.
（実施例１２）
　以下のようにして調製した熱可塑性樹脂フィルムを用いた以外は実施例１と同様にして、光学レンズを製造した。そして、実施例１と同様にして各種測定及び評価を行った。結果を表１に示す。
＜熱可塑性樹脂フィルムの調製＞
　ポリエステル樹脂（ＯＫＰ－１（大阪ガスケミカル社製）、ガラス転移温度：１３２℃）を、フィルム押出成形機（単軸押出機、φ＝２０ｍｍ、ＧＳＩクレオス社製）に入れ、２６０℃で溶融し、溶融樹脂をＴダイから押し出し、冷却して、最大厚みが２０２μｍ、最小厚みが１９８μｍ、厚みばらつきが４μｍである、幅２８０ｍｍの熱可塑性樹脂フィルムを得た。なお、熱可塑性フィルムの幅方向に垂直な方向が長手方向となっており、ロール・ツー・ロール成形法により成形するために充分な長さを有していた。 (Example 12)
An optical lens was produced in the same manner as in Example 1 except that the thermoplastic resin film prepared as follows was used. Then, various measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.
<Preparation of thermoplastic resin film>
A polyester resin (OKP-1 (manufactured by Osaka Gas Chemical Co., Ltd.), glass transition temperature: 132 ° C.) was placed in a film extruder (single-screw extruder, φ = 20 mm, manufactured by GSI Creos) and melted at 260 ° C. The molten resin was extruded from the T-die and cooled to obtain a thermoplastic resin film having a width of 280 mm, a maximum thickness of 202 μm, a minimum thickness of 198 μm, and a thickness variation of 4 μm. The direction perpendicular to the width direction of the thermoplastic film is the longitudinal direction, and has a sufficient length for molding by the roll-to-roll molding method.
（実施例１３）
　以下のようにして調製した熱可塑性樹脂フィルムを用いた以外は実施例１と同様にして、光学レンズを製造した。そして、実施例１と同様にして各種測定及び評価を行った。結果を表１に示す。
＜熱可塑性樹脂フィルムの調製＞
　ノルボルネン系開環重合体水素化物を含む熱可塑性樹脂（ＺＥＯＮＥＸＥ４８Ｒ（日本ゼオン社製）、ガラス転移温度：１３９℃）を、フィルム押出成形機（単軸押出機、φ＝２０ｍｍ、ＧＳＩクレオス社製）に入れ、これを２６０℃で溶融し、溶融樹脂をＴダイから押し出し、これを冷却して、最大厚みが３５２μｍ、最小厚みが３４８μｍ、厚みばらつきが４μｍである、幅２８０ｍｍの熱可塑性樹脂フィルムを得た。なお、熱可塑性フィルムの幅方向に垂直な方向が長手方向となっており、ロール・ツー・ロール成形法により成形するために充分な長さを有していた。 (Example 13)
An optical lens was produced in the same manner as in Example 1 except that the thermoplastic resin film prepared as follows was used. Then, various measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.
<Preparation of thermoplastic resin film>
A thermoplastic resin containing a norbornene-based ring-opening polymer hydride (ZEONEXE48R (manufactured by Nippon Zeon), glass transition temperature: 139 ° C.) was used in a film extruder (single-screw extruder, φ = 20 mm, manufactured by GSI Creos). A thermoplastic resin film having a width of 280 mm having a maximum thickness of 352 μm, a minimum thickness of 348 μm, and a thickness variation of 4 μm was obtained by extruding the molten resin from the T-die by melting it at 260 ° C. Obtained. The direction perpendicular to the width direction of the thermoplastic film is the longitudinal direction, and has a sufficient length for molding by the roll-to-roll molding method.
（実施例１４）
　平板金型を変更し、得られる光学レンズを凸メニスカスレンズとし、平板金型の最浅部の深さの合計（Ｄmin）を１５０μｍ、光学面形成領域における最深部の深さの合計（Ｄmax）を３００μｍとした以外は実施例１と同様にして、光学レンズを製造した。そして、実施例１と同様の各種測定及び評価を行った。結果を表１に示す。 (Example 14)
The flat plate mold is changed, the obtained optical lens is a convex meniscus lens, the total depth of the shallowest part of the flat plate mold (D min ) is 150 μm, and the total depth of the deepest part in the optical surface forming region (D). An optical lens was manufactured in the same manner as in Example 1 except that max ) was set to 300 μm. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 1.
（比較例１）
　金型加熱工程、熱プレス工程、金型冷却工程、及び離型工程において熱可塑性樹脂フィルムに対して張力をかけなかった以外は、実施例１と同様にして、光学レンズを製造した。そして、実施例１と同様の各種測定及び評価を行った。結果を表２に示す。 (Comparative Example 1)
An optical lens was manufactured in the same manner as in Example 1 except that no tension was applied to the thermoplastic resin film in the mold heating step, the hot pressing step, the mold cooling step, and the mold releasing step. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 2.
（比較例２）
　金型冷却工程にて平板金型を熱可塑性樹脂フィルムのガラス転移温度（Ｔｇｒ）℃以下の温度まで冷却しなかった以外は、実施例１と同様にして、光学レンズを製造した。そして、実施例１と同様の各種測定及び評価を行った。結果を表２に示す。 (Comparative Example 2)
Except that the flat die at a die cooling process was not cooled to the glass transition temperature (Tg r) ° C. below the temperature of the thermoplastic resin film, in the same manner as in Example 1 to produce an optical lens. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 2.
（比較例３）
　実施例で用いたような、図１に従う概略構成を有する装置ではなく、図１に従う概略構成における上部金型１Ａ及び下部金型１Ｂに代えてエンボスロールを備える概略構成を有する装置を用いた。エンボスロールのエンボス形状は、実施例１と同様の形状の光学レンズを製造可能な形状であった。また、冷却工程は実施しなかった。これらの点以外は実施例１と同様にして、光学レンズを製造した。そして、実施例１と同様の各種測定及び評価を行った。結果を表２に示す。 (Comparative Example 3)
Instead of the device having the schematic configuration according to FIG. 1 as used in the examples, the device having the schematic configuration having an embossing roll instead of the upper mold 1A and the lower mold 1B in the schematic configuration according to FIG. 1 was used. The embossed shape of the embossed roll was a shape capable of manufacturing an optical lens having the same shape as that of the first embodiment. Moreover, the cooling step was not carried out. An optical lens was manufactured in the same manner as in Example 1 except for these points. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 2.
（比較例４）
　表２に示す各条件に従って射出成形法を実施して、光学レンズを製造した。射出成形材料としては、実施例１と同じノルボルネン系開環重合体水素化物を含む熱可塑性樹脂を用いた。射出成形装置としてはファナック社製の「ＲＯＢＯＳＨＯＴ Ｓ２０００ｉ１００Ａ」を用いた。射出成形金型としては、実施例１と同様の形状の光学レンズを製造可能な、１６個取り金型を用いた。これらを用いて、射出速度３０ｍｍ／秒、保圧８０ＭＰａとして、１０回の製造工程を行って１６０個の光学レンズを製造した。そして、実施例１と同様の各種測定及び評価を行った。結果を表２に示す。 (Comparative Example 4)
An optical lens was manufactured by carrying out an injection molding method according to each condition shown in Table 2. As the injection molding material, the same thermoplastic resin containing the norbornene-based ring-opening polymer hydride as in Example 1 was used. As the injection molding apparatus, "ROBOSHOT S2000i100A" manufactured by FANUC Corporation was used. As the injection molding die, a 16-piece die capable of producing an optical lens having the same shape as in Example 1 was used. Using these, 160 optical lenses were manufactured by performing 10 manufacturing steps at an injection speed of 30 mm / sec and a holding pressure of 80 MPa. Then, various measurements and evaluations similar to those in Example 1 were performed. The results are shown in Table 2.
　なお、表１及び表２において、「ＮＢ-ＲＯ」は、ノルボルネン系開環重合体水素化物を含む熱可塑性樹脂を、「ＮＢ／ＥＴ」は、ノルボルネン－エチレンランダム共重合体を、「ＰＣ」はポリカーボネート樹脂を、「ＡＣＲ」はポリメチルメタクリレート樹脂を、「ＰＥｓ」はポリエステル樹脂を、それぞれ示す。 In Tables 1 and 2, "NB-RO" is a thermoplastic resin containing a norbornene-based ring-opening polymer hydride, and "NB / ET" is a norbornene-ethylene random copolymer, "PC". Indicates a polycarbonate resin, "ACR" indicates a polymethylmethacrylate resin, and "PEs" indicates a polyester resin.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１より、熱可塑性樹脂フィルムを、一対の平板金型により熱プレスして熱プレスフィルムを得る熱プレス工程と、平板金型をガラス転移温度（Ｔｇｒ）℃以下の温度まで冷却する金型冷却工程と、熱プレスフィルムに対して張力をかけながら離型する離型工程と、を含む本発明の製造方法を実施した実施例１～１４では、低複屈折性であるとともに形状精度の高い透過型光学素子（光学レンズ）を効率的に製造することができたことが分かる。一方、表２より、離型工程において熱プレスフィルムに対して張力をかけなかった比較例１、金型冷却工程にて平板金型をガラス転移温度（Ｔｇｒ）℃以下の温度まで冷却しなかった比較例２、平板金型を使用しなかった比較例３及び４では、低複屈折性であるとともに形状精度の高い透過型光学素子を効率的に製造することができなかったことが分かる。 From Table 1, the thermoplastic resin film, a heat press to obtain a hot press film was hot pressed by a pair of flat dies, molds for cooling the flat die to the glass transition temperature (Tg r) ° C. below the temperature In Examples 1 to 14 in which the manufacturing method of the present invention including the cooling step and the mold releasing step of releasing the mold while applying tension to the hot press film are carried out, the film has low compound refractive index and high shape accuracy. It can be seen that the transmissive optical element (optical lens) could be efficiently manufactured. On the other hand, from Table 2, no cooling Comparative Example 1 that did not tensioned, the flat die at a die cooling process to the glass transition temperature (Tg r) ° C. The following temperatures for hot pressed film in the releasing step It can be seen that in Comparative Example 2 and Comparative Examples 3 and 4 in which the flat plate mold was not used, a transmission type optical element having low double refractive index and high shape accuracy could not be efficiently manufactured.
　本発明の透過型光学素子の製造方法によれば、低複屈折性であるとともに形状精度の高い透過型光学素子を効率的に製造することができる。 According to the method for manufacturing a transmission type optical element of the present invention, it is possible to efficiently manufacture a transmission type optical element having low birefringence and high shape accuracy.
１Ａ、１Ａ’、１Ａ”　　　　上部金型
１Ｂ、１Ｂ’、１Ｂ”　　　　下部金型
２Ａ　　　　　　　　　　　　上部温度調節装置
２Ｂ　　　　　　　　　　　　下部温度調節装置
３　　　　　　　　　　　　　ｚ軸方向移動テーブル
４　　　　　　　　　　　　　下部テーブル
５Ａ　　　　　　　　　　　　巻き出しロール
５Ｂ　　　　　　　　　　　　巻取りロール
６　　　　　　　　　　　　　送りロール
７　　　　　　　　　　　　　熱可塑性樹脂フィルム
８’、８”　　　　　　　　　光学レンズ
１００　　　　　　　　　　　透過型光学素子製造装置 1A, 1A', 1A " Upper mold 1B, 1B', 1B" Lower mold 2A Upper temperature control device 2B Lower temperature control device 3 z-axis direction moving table 4 Lower table 5A Unwinding roll 5B Winding roll 6 Feeding roll 7 Thermoplastic resin film 8', 8 "optical lens 100 transmission type optical element manufacturing equipment

Claims (11)

  1. 　熱可塑性樹脂フィルムを用いて透過型光学素子を製造する製造方法であって、
    　前記熱可塑性樹脂フィルムを、少なくとも一対の平板金型により熱プレスして熱プレスフィルムを得る熱プレス工程と、
    　前記一対の平板金型を前記熱可塑性樹脂フィルムのガラス転移温度（Ｔｇｒ）℃以下の温度まで冷却して、前記熱プレスフィルムを冷却する金型冷却工程と、
    　前記金型冷却工程の後に、前記熱プレスフィルムを前記一対の平板金型から離型するにあたり、前記熱プレスフィルムに対して張力をかけながら離型して、複数の透過型光学素子を含む成形フィルムを得る離型工程と、
    を含む、透過型光学素子の製造方法。     A manufacturing method for manufacturing a transmissive optical element using a thermoplastic resin film.
    A hot pressing step of hot pressing the thermoplastic resin film with at least a pair of flat plate dies to obtain a hot press film.
    And cooling said pair of plate molds to the glass transition temperature (Tg r) ° C. below the temperature of the thermoplastic resin film, and the mold cooling step of cooling the hot press film,
    After the mold cooling step, when the hot press film is released from the pair of flat plate molds, the hot press film is released while applying tension to form a mold including a plurality of transmissive optical elements. The mold release process to obtain the film and
    A method for manufacturing a transmissive optical element, including the above.
  2. 　前記熱プレス工程に先立って、前記熱可塑性樹脂フィルムを、所定の搬送方向に沿って搬送する搬送工程を更に含み、
    　前記離型工程にて前記搬送方向に沿って張力をかけながら離型し、且つ、前記張力の大きさが、前記搬送方向に対して直交する方向の前記熱可塑性樹脂フィルムの幅１ｍあたり、１Ｎ以上２０００Ｎ以下である、請求項１に記載の透過型光学素子の製造方法。     Prior to the heat pressing step, a transport step of transporting the thermoplastic resin film along a predetermined transport direction is further included.
    In the mold release step, the mold is released while applying tension along the transport direction, and the magnitude of the tension is 1 N per 1 m of width of the thermoplastic resin film in a direction orthogonal to the transport direction. The method for manufacturing a transmissive optical element according to claim 1, which is 2000 N or less.
  3. 　前記一対の平板金型のうちの少なくとも一方は、直径が１ｍｍ以上１５ｍｍ以下である複数の光学面形成領域と、当該複数の光学面形成領域の各外周に隣接する領域である外周部形成領域とを含んでおり、且つ
    　前記一対の平板金型の前記光学面形成領域及び前記外周部形成領域における最浅部の深さの合計が、５００μｍ以下である、請求項１又は２に記載の透過型光学素子の製造方法。     At least one of the pair of flat plate molds has a plurality of optical surface forming regions having a diameter of 1 mm or more and 15 mm or less, and an outer peripheral portion forming region which is a region adjacent to each outer periphery of the plurality of optical surface forming regions. The transmission mold according to claim 1 or 2, wherein the total depth of the optical surface forming region and the shallowest portion in the outer peripheral portion forming region of the pair of flat plate molds is 500 μm or less. Manufacturing method of optical element.
  4. 　前記一対の平板金型のうちの少なくとも一方が、該平板金型の平面方向にて離散配置された複数の光学面形成領域を含み、
    　該複数の光学面形成領域間の最小間隔が１．０ｍｍ以上である、
    請求項１～３の何れかに記載の透過型光学素子の製造方法。     At least one of the pair of flat plate molds includes a plurality of optical surface forming regions discretely arranged in the plane direction of the flat plate molds.
    The minimum distance between the plurality of optical surface forming regions is 1.0 mm or more.
    The method for manufacturing a transmissive optical element according to any one of claims 1 to 3.
  5. 　前記熱可塑性樹脂フィルムのガラス転移温度（Ｔｇｒ）が１００℃以上２００℃以下である、請求項１～４の何れかに記載の透過型光学素子の製造方法。 Glass transition temperature (Tg r) is 200 ° C. or less 100 ° C. or higher of the thermoplastic resin film, a manufacturing method of a transmission type optical element according to any one of claims 1 to 4.
  6. 　前記熱プレス工程における前記一対の平板金型の温度が（Ｔｇｒ＋３０）℃以上（Ｔｇｒ＋７０）℃以下である、請求項１～５の何れかに記載の透過型光学素子の製造方法。 Method of manufacturing a transmission type optical element according to any one of the heat temperature of the pair of flat dies in the press step (Tg r +30) ℃ or higher (Tg r +70) is ° C. or less, according to claim 1-5.
  7. 　前記金型冷却工程において、前記一対の平板金型を（Ｔｇｒ－１５）℃以下の温度まで冷却する、請求項１～６の何れかに記載の透過型光学素子の製造方法。 In the mold cooling step, cooling said pair of plate molds to (Tg r -15) ℃ temperature below, a manufacturing method of a transmission type optical element according to any one of claims 1 to 6.
  8. 　前記熱可塑性樹脂フィルムが脂環構造含有樹脂を含む、請求項１～７の何れかに記載の透過型光学素子の製造方法。 The method for manufacturing a transmissive optical element according to any one of claims 1 to 7, wherein the thermoplastic resin film contains an alicyclic structure-containing resin.
  9. 　前記一対の平板金型のうちの少なくとも一方が、０．１６個／ｃｍ２以上の個数密度で光学面形成領域を有する、請求項１～８の何れかに記載の透過型光学素子の製造方法。 The method for manufacturing a transmissive optical element according to any one of claims 1 to 8, wherein at least one of the pair of flat plate molds has an optical surface forming region at a number density of 0.16 pieces / cm 2 or more. ..
  10. 　前記一対の平板金型の両方が、複数の光学面形成領域を有する、請求項１～９の何れかに記載の透過型光学素子の製造方法。 The method for manufacturing a transmissive optical element according to any one of claims 1 to 9, wherein both of the pair of flat plate molds have a plurality of optical surface forming regions.
  11. 　前記離型工程を経て得られた前記成形フィルムから、前記複数の透過型光学素子を分離する透過型光学素子分離工程を含む、請求項１～１０の何れかに記載の透過型光学素子の製造方法。 The production of the transmissive optical element according to any one of claims 1 to 10, further comprising a transmissive optical element separation step of separating the plurality of transmissive optical elements from the molded film obtained through the mold release step. Method.
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