WO2021153512A1 - Molded sheet, method for manufacturing molded sheet, and method for manufacturing optical element - Google Patents

Molded sheet, method for manufacturing molded sheet, and method for manufacturing optical element Download PDF

Info

Publication number
WO2021153512A1
WO2021153512A1 PCT/JP2021/002480 JP2021002480W WO2021153512A1 WO 2021153512 A1 WO2021153512 A1 WO 2021153512A1 JP 2021002480 W JP2021002480 W JP 2021002480W WO 2021153512 A1 WO2021153512 A1 WO 2021153512A1
Authority
WO
WIPO (PCT)
Prior art keywords
molded sheet
optical
sheet
optical surface
thermoplastic resin
Prior art date
Application number
PCT/JP2021/002480
Other languages
French (fr)
Japanese (ja)
Inventor
遠藤　充輝
浩成 摺出寺
Original Assignee
日本ゼオン株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
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 KR1020227023478A priority Critical patent/KR20220133188A/en
Priority to JP2021574028A priority patent/JPWO2021153512A1/ja
Priority to CN202180006956.0A priority patent/CN114786903A/en
Publication of WO2021153512A1 publication Critical patent/WO2021153512A1/en

Links

Images

Classifications

    • 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
    • B29C43/02—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B11/00—Making preforms
    • B29B11/06—Making preforms by moulding the material
    • B29B11/12—Compression moulding
    • 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
    • B29C43/36—Moulds for making articles of definite length, i.e. discrete 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
    • B29C43/52—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
    • B29C51/08—Deep drawing or matched-mould forming, i.e. using mechanical means only
    • B29C51/082—Deep drawing or matched-mould forming, i.e. using mechanical means only by shaping between complementary mould parts
    • 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
    • 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
    • B29D11/00413—Production of simple or compound lenses made by moulding between two mould parts which are not in direct contact with one another, e.g. comprising a seal between or on the edges
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2101/00—Use of unspecified macromolecular compounds as moulding material
    • B29K2101/12—Thermoplastic materials

Definitions

  • the present invention relates to a molded sheet, a method for manufacturing a molded sheet, and a method for manufacturing an optical element.
  • a molding sheet, a method for manufacturing a molded sheet, and a method for manufacturing an optical element are useful for manufacturing a transmission type optical element.
  • 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. Further, in the lens obtained according to the injection molding method, birefringence was likely to occur. 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 of arranging a plurality of molds in the plane direction of a resin sheet and simultaneously molding a plurality of lens portions. More specifically, in Patent Document 1, a resin sheet is placed on a plurality of female lower molds made of metal or the like in a positioned state, and on a plurality of male shapes made of metal or the like. A method of plastically deforming a resin sheet by pressing a mold to mold a plurality of lens portions at the same time is disclosed.
  • the resin sheet has a plurality of optical planar portions that can be used as, for example, a lens or the like.
  • a molded sheet is manufactured, it is not possible to efficiently manufacture a molded sheet having a plurality of optical planar portions, which has sufficiently high shape accuracy, small variation in thickness accuracy, and low birefringence. rice field.
  • a further object of the present invention is to provide a method for manufacturing an optical element using the molded sheet.
  • the present inventors have conducted diligent studies to achieve the above object. Then, the present inventors have sufficiently high shape accuracy, small variation in thickness accuracy, and low birefringence by hot-press molding a sheet-fed sheet material made of a thermoplastic resin film under predetermined conditions.
  • the present invention has been completed by finding that it is possible to provide a molded sheet having a plurality of optically planar parts having refractive properties.
  • the present invention aims to advantageously solve the above problems, and the method for producing a molded sheet of the present invention is to heat-press mold a thermoplastic resin film formed using a thermoplastic resin.
  • a method for producing a molded sheet which comprises producing a molded sheet having a plurality of optical surface-like portions, wherein the sheet-fed sheet material made of the thermoplastic resin film has a plurality of optical surface forming regions separated from each other. It is characterized by including a hot press step of obtaining a molded sheet by hot press molding under normal pressure using a pair of dies.
  • the sheet-fed sheet material is hot-press molded under normal pressure using a pair of dies having a plurality of optical surface forming regions separated from each other, the shape accuracy is sufficiently high and the thickness accuracy varies. It is possible to easily manufacture a molded sheet having a plurality of optical planar portions, which is small and has low birefringence.
  • the fact that the sheet material is "single-leaf” means that the sheet material is cut to a predetermined size and is not in a wound state.
  • the "normal pressure” is a pressure pressure when pressurization and depressurization are not performed at a certain point, and is usually a pressure equal to the atmospheric pressure at that point. More specifically, "normal pressure” means the pressure range in the standard state defined in JIS Z8703: 1983, which is within the range of atmospheric pressure of 86 kPa or more and 106 kPa or less.
  • the method for producing a molded sheet of the present invention sets the glass transition temperature of the thermoplastic resin to Tg (° C.), and when the molded sheet obtained in the heat pressing step is released from the pair of dies. It is preferable to include a mold removal step of releasing the pair of molds at a temperature of (Tg-80) ° C. or higher (Tg-15) ° C. or lower.
  • Tg-80 a temperature of (Tg-80) ° C. or higher (Tg-15) ° C. or lower.
  • the sheet-fed sheet material is pressed by the pair of dies, and the sheet-fed sheet material is used as the pair of dies. It is preferable that it does not stick out.
  • the shape accuracy of the plurality of optical surface-like parts contained in the obtained molded sheet is further improved, and the variation in thickness accuracy is further reduced.
  • the birefringence can be further reduced, and the production efficiency of the molded sheet can be improved.
  • the thermoplastic resin is an alicyclic structure-containing resin. If the thermoplastic resin is an alicyclic structure-containing resin, the shape accuracy of a plurality of optical surface-like portions contained in the obtained molded sheet can be further improved, the variation in thickness accuracy can be further reduced, and the production efficiency of the molded sheet can be further reduced. Can be enhanced.
  • the present invention also aims to advantageously solve the above problems, and the method for manufacturing an optical element of the present invention is to obtain a molded sheet according to any of the above-mentioned molding sheet manufacturing methods. It is characterized in that a plurality of optical elements are obtained by separating the plurality of optical surface-shaped portions at positions corresponding to each of them. According to the manufacturing method of the present invention, it is possible to easily manufacture an optical element having sufficiently high shape accuracy, small variation in thickness accuracy, and sufficiently small birefringence.
  • the present invention also aims to advantageously solve the above problems, and the molded sheet of the present invention is a single-wafer-shaped sheet having a plurality of optical surface-like portions formed by using a thermoplastic resin.
  • the arrangement density of the optical planar portions is 0.16 pieces / cm 2 or more
  • the minimum distance between the optical planar portions adjacent to each other is 1.0 mm or more
  • the above-mentioned in a plan view is that the diameter of the optical surface portion is 1 mm or more and 15 mm or less
  • the phase difference of the optical surface portion is 50 nm or less
  • the variation in the thickness accuracy of the optical surface portion is 0.2 ⁇ m or less. ..
  • the optical surface-shaped portion of the molded sheet has a shape accuracy. Excellent. Further, by using such a molded sheet, an optical element having excellent optical performance can be efficiently manufactured.
  • the "phase difference” and “variation in thickness accuracy” can be evaluated or measured by using the method described in the examples.
  • At least one surface of the optical surface-like portion has an aspherical shape having an inflection point in the cross-sectional shape in the thickness direction.
  • An optical planar portion having such a shape can be advantageously used as a transmissive optical element such as a lens.
  • a molded sheet having a plurality of optical planar portions which has sufficiently high shape accuracy, small variation in thickness accuracy, and low birefringence. Further, according to the present invention, it is possible to provide a method for producing a molded sheet capable of efficiently producing the molded sheet. Further, according to the present invention, it is possible to provide a method for manufacturing an optical element using the above-mentioned molded sheet.
  • the method for producing a molded sheet of the present invention can be used, for example, when producing the molded sheet of the present invention.
  • the method for manufacturing an optical element of the present invention can be suitably applied when manufacturing an optical element using a molded sheet obtained according to the method for manufacturing a molded sheet of the present invention.
  • the molded sheet according to the present invention is not particularly limited, and can be suitably used for manufacturing an optical element having optical surfaces having various shapes.
  • the "optical surface” means an interface that can exert optical actions such as reflection, refraction, and transmission on light, and its shape includes a flat surface, a spherical surface, an aspherical surface, a free curved surface, and a lenticular. And Fresnel and the like.
  • examples of the "optical element” that can be suitably manufactured using the molded sheet according to the present invention include a transmission type 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 other than an optical lens, which exhibits a light dispersion action, a refraction action, a total reflection action, and / or a birefringence action.
  • the molded sheet according to the present invention it is possible to efficiently obtain a transmissive optical element having high shape accuracy and low birefringence (that is, a small phase difference).
  • the molded sheet according to the present invention can be suitably used when manufacturing an aspherical lens having inflection points on one side and / or both sides among optical elements having various shapes. Then, the aspherical lens can be suitably used as, for example, a lens of a camera unit of a small electronic electric device.
  • the molded sheet of the present invention has a cross-sectional shape along the thickness direction, for example, as shown in FIG. 1, is a sheet-fed molded sheet 10 formed by using a thermoplastic resin, and has a plurality of optical surface-like portions 11. Have.
  • the arrangement density of the optical surface portions 11 is 0.16 pieces / cm 2 or more, and the minimum distance P between the optical surface portions 11 adjacent to each other is 1.0 mm or more.
  • the diameter D of the optical surface portion 11 in a plan view is 1 mm or more and 15 mm or less
  • the phase difference of the optical surface portion 11 is 50 nm or less
  • the variation in the thickness accuracy of the optical surface portion 11 is 0.2 ⁇ m or less. Need to be. If the arrangement density, the minimum spacing, the diameter and the phase difference of the optical surface-like portions, and the variation in the thickness accuracy are within the above ranges, the shape accuracy can be improved. Further, by using such a molded sheet, an optical element having excellent optical performance can be efficiently manufactured.
  • the shape of the optical surface of the molded sheet is not limited to the shape shown in FIG.
  • the optical surface of the molded sheet is not particularly limited, and can be suitably used as a lens by cutting out from the molded sheet, for example.
  • thermoplastic resin examples include (meth) acrylic resin, alicyclic structure-containing resin, styrene resin, polycarbonate resin, polyester resin, polyether resin, urethane resin, and thiourethane resin.
  • (meth) acrylic refers to acrylic and / or methacryl.
  • one type of the above-mentioned thermoplastic resin may be used alone, or two or more types may be mixed and used.
  • the thermoplastic resin can further improve the shape accuracy of the plurality of optical planar parts contained in the obtained molded sheet, further reduce the variation in thickness accuracy, and further improve the production efficiency of the molded sheet.
  • the thermoplastic resin Preferably contains an alicyclic structure-containing resin.
  • the thermoplastic resin contains an alicyclic structure-containing resin.
  • 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 a molded sheet having excellent mechanical strength and heat resistance can be easily obtained.
  • 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 proportion of repeating units of 50% by mass or more the shape accuracy of a plurality of optical surface-like portions contained in the obtained molded sheet is further improved, and the thickness accuracy is further improved. It is possible to further reduce the variation of the molded sheet and further improve the production efficiency of the molded sheet. Further, by using an alicyclic structure-containing polymer having an alicyclic structure and a proportion of repeating units of 50% by mass or more, it becomes easy to obtain a molded sheet having excellent transparency and heat resistance.
  • the alicyclic structure-containing polymer examples include norbornene-based polymers, monocyclic cyclic olefin-based polymers, cyclic conjugated diene-based polymers, and vinyl alicyclic hydrocarbon-based polymers.
  • norbornene-based polymers from the viewpoint of improving the transparency, heat resistance, and mechanical strength of the obtained molded sheet, and further improving the shape accuracy of the plurality of optical planar parts contained in the obtained molded sheet, the thickness accuracy varies.
  • a norbornene-based polymer is preferable from the viewpoint of making it smaller and further increasing the production efficiency of the molded sheet.
  • the norbornene-based polymer can further improve the shape accuracy of the plurality of optical planar portions contained in the obtained molded sheet, further reduce the variation in thickness accuracy, and further improve the production efficiency of the molded sheet. Is preferable.
  • 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 norbornene-based ring-opening polymer hydride By using the norbornene-based ring-opening polymer hydride, the transparency, heat resistance, mechanical strength, etc. of the molded sheet can be further improved, and the mold can be released when the molded sheet is manufactured by hot press molding. The sex and transferability can be enhanced.
  • 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.
  • 8-methoxycarbonyl-tetracyclo [4.4.0.1 2,5 . 17 and 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 ring-opening copolymerizable with norbornene-based monomers 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 glass transition temperature (Tg) of the thermoplastic resin is not particularly limited, but is preferably 100 ° C. or higher, more preferably 120 ° C. or higher, preferably 200 ° C. or lower, and more preferably 160 ° C. or lower.
  • Tg glass transition temperature
  • the glass transition temperature (Tg) of the thermoplastic resin is equal to or higher than the above lower limit value, the shape accuracy of the optical surface portion of the molded sheet can be further improved, and the variation in the thickness accuracy of the optical surface portion can be reduced. Furthermore, it is possible to improve the manufacturing efficiency of the molded sheet. Further, when the glass transition temperature (Tg) of the thermoplastic resin film is not more than the above upper limit value, the production efficiency of the molded sheet can be improved and the shape accuracy of the optical surface portion can be further improved.
  • the molded sheet 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, infrared absorbers, antioxidants, mold release agents, antistatic agents, carbon materials (carbon, etc.), pigments, and dyes. Be done.
  • 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 arrangement density of the optical surface portion (11 in FIG. 1) needs to be 0.16 pieces / cm 2 or more, and the arrangement density of the optical surface part is 0.30 pieces / cm 2 or more. It is preferably 0.40 pieces / cm 2 or more, more preferably 3.0 pieces / cm 2 or less, and more preferably 2.0 pieces / cm 2 or less. It is more preferably 1.0 piece / cm 2 or less, and particularly preferably 0.60 piece / cm 2 or less.
  • the arrangement density of the optical surface portion is 0.16 pieces / cm 2 or more, the variation in the thickness accuracy of the optical surface portion can be reduced and the shape accuracy can be improved. Further, when the arrangement density of the optical surface portion is not more than the above upper limit value, the shape accuracy can be improved, the birefringence can be reduced, and the variation in the thickness accuracy can be further reduced. ..
  • the minimum distance (P in FIG. 1) between the optical plane portions adjacent to each other needs to be 1.0 mm or more, preferably 3.0 mm or more, and preferably 5.0 mm or more. Is more preferable, and 7.0 mm or more is further preferable.
  • the minimum distance between the optical surface portions is 1.0 mm or more, the variation in the thickness accuracy of the optical surface portions can be reduced, the shape accuracy can be improved, and the birefringence can be reduced. be able to.
  • the minimum distance between the optical surface portions is 1.0 mm or more, the generation of air bubbles and air pools in the molded sheet is suppressed even when the molding method such as press molding is used. be able to.
  • the minimum distance between the optical surface portions is usually 20 mm or less.
  • the diameter of the optical surface portion (D in FIG. 1) in a plan view needs to be 1 mm or more and 15 mm or less, and the diameter of the optical surface portion is preferably 3 mm or more, preferably 9 mm or less. It is preferable to have.
  • the diameter of the optical surface portion is within the above range, the variation in the thickness accuracy of the optical surface portion can be reduced and the shape accuracy can be improved.
  • the thickness of the center of the optical surface portion (H mid in FIG. 1) is preferably 50 ⁇ m or more, more preferably 100 ⁇ m or more, preferably 1500 ⁇ m or less, and preferably 1000 ⁇ m or less. More preferred. When the thickness of the center of the optical surface portion is within the above range, it can be advantageously used as a transmissive optical element such as a lens.
  • the variation in the thickness accuracy of the optical surface portion needs to be 0.2 ⁇ m or less, and is preferably 0.1 ⁇ m or less.
  • the variation in thickness accuracy is not more than the above upper limit value, the birefringence in the optical surface portion can be reduced.
  • the phase difference of the optical surface portion needs to be 50 nm or less, and preferably 20 nm or less.
  • the phase difference is not more than the above upper limit value, the birefringence in the optical surface portion is sufficiently small.
  • the phase difference is set to be equal to or less than the above upper limit value, the variation in the thickness accuracy of the optical surface portion can be reduced and the shape accuracy can be improved.
  • the thickness of the thinnest portion (H min in FIG. 1) of the molded sheet is preferably 50 ⁇ m or more, more preferably 100 ⁇ m or more, preferably 500 ⁇ m or less, and preferably 300 ⁇ m or less. More preferably, it is more preferably 200 ⁇ m or less.
  • the thickness of the thinnest portion is equal to or less than the above upper limit value, the variation in the thickness accuracy of the optical surface portion can be reduced and the shape accuracy can be improved. Further, when the thickness of the thinnest portion is at least the above lower limit value, the strength of the molded sheet can be sufficiently increased.
  • the method for producing a molded sheet of the present invention is a method for producing a molded sheet having a plurality of optical planar portions by hot-press molding a thermoplastic resin film formed using a thermoplastic resin, and is particularly limited. It can be used, for example, when producing the molded sheet of the present invention described above. Then, in the method for producing a molded sheet of the present invention, a sheet-fed sheet material made of a thermoplastic resin film is hot-press molded under normal pressure using a pair of dies having a plurality of optical surface forming regions separated from each other. It is characterized by including a "heat pressing process" for obtaining a molded sheet.
  • the method for producing a molded sheet of the present invention preferably includes a "mold release step” in which a molded sheet obtained in a hot pressing step is released from a pair of dies.
  • a "mold release step” in which a molded sheet obtained in a hot pressing step is released from a pair of dies.
  • the molded sheet produced by the method for producing a molded sheet of the present invention is not particularly limited as long as it is a single-wafer-shaped sheet having a plurality of optical plane-like portions separated from each other. Above all, it is preferable that the molded sheet has the same properties as the molded sheet of the present invention described above.
  • thermoplastic resin used for the thermoplastic resin film is not particularly limited, and examples thereof include the same thermoplastic resin as the above-mentioned molded sheet of the present invention.
  • 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.
  • 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 producing a thermoplastic resin film, and then the thermoplastic resin film is produced by a melt extrusion molding method, a melt casting method, an injection molding method, or the like. Obtainable.
  • the thickness of the thermoplastic resin film can be appropriately selected according to the diameter of the optical surface of the molded sheet 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 a simple arithmetic mean value of the thicknesses at a plurality of randomly selected measurement points.
  • thermoplastic resin film can be cut into a desired size such as A4 size to 50 cm ⁇ 50 cm size to obtain a single-wafer-shaped sheet material.
  • FIG. 2 shows a schematic view for explaining a heat pressing process in the method for producing a molded sheet according to an example of the present invention.
  • the sheet-fed sheet material 10' is heat-pressed using a pair of dies 1 composed of an upper die 1A and a lower die 1B. Then, as shown in the lower part of FIG.
  • the single-wafer-shaped sheet material 10' in a state where the single-wafer-shaped sheet material 10'is pressed by the pair of dies 1, the single-wafer-shaped sheet material 10'does not protrude from the pair of dies 1.
  • the shape accuracy of the plurality of optical surface-like portions contained in the obtained molded sheet is further improved, and the thickness accuracy varies. Further, the birefringence can be further reduced, and the production efficiency of the molded sheet can be improved.
  • birefringence occurs in the optical surface of the obtained molded sheet by subjecting the thermoplastic resin film to a hot press using a mold regardless of the injection molding method. Can be suppressed.
  • the pair of molds 1 is not particularly limited as long as at least one of them has a plurality of cavity portions which are optical surface-shaped portions forming regions, and a mold having an arbitrary shape such as a flat plate mold is used. obtain.
  • a known material can be used. Examples thereof include carbon steel, stainless steel, and alloys based on these. Among them, stainless steel such as STAVAX (registered trademark) material (manufactured by Uddeholms) 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.
  • At least one of the molds used in the manufacturing method of the present invention has a plurality of cavity portions discretely arranged in the plane direction of the mold. It is preferable that the plurality of cavities are arranged at equal intervals in the plane direction of the mold.
  • both of the pair of molds may have a plurality of cavities. This is because a molded sheet having both sides shaped can be efficiently manufactured by molding using a pair of dies each having a cavity portion.
  • the shapes of the pair of dies may be the same or different depending on the shape of the molded sheet to be manufactured.
  • the cavity portion preferably has an arrangement density of 0.16 pieces / cm 2 or more, more preferably 0.30 pieces / cm 2 or more, and further preferably 0.40 pieces / cm 2 or more. Preferably, it is 3.0 pieces / cm 2 or less, more preferably 2.0 pieces / cm 2 or less, further preferably 1.0 piece / cm 2 or less, and 0.60 pieces. It is particularly preferable that it is / cm 2 or less.
  • the arrangement density of the cavity portion is 0.16 pieces / cm 2 or more, the variation in the thickness accuracy of the optical surface-shaped portion of the obtained molded sheet can be reduced, and the shape accuracy can be improved. Further, when the arrangement density of the cavity portion is not more than the above upper limit value, the shape accuracy of the obtained molded sheet can be improved, the birefringence can be reduced, and the variation in thickness accuracy can be further reduced. be able to.
  • the minimum distance between the cavities adjacent to each other is preferably 1.0 mm or more, more preferably 3.0 mm or more, and preferably 5.0 mm or more. It is more preferably 7.0 mm or more, and particularly preferably 7.0 mm or more.
  • the minimum distance (P) between the cavities is 1.0 mm or more, the variation in the thickness accuracy of the optical surface portion of the obtained molded sheet can be reduced, the shape accuracy can be improved, and further, the shape accuracy can be improved. , Birefringence can be reduced.
  • the minimum distance between the cavities is usually 20 mm or less.
  • the diameter of the cavity portion (corresponding to D in FIG. 1) in a plan view is preferably 1 mm or more and 15 mm or less, more preferably 3 mm or more, and preferably 9 mm or less.
  • the diameter of the cavity portion is within the above range, the variation in the thickness accuracy of the optical surface-shaped portion of the obtained molded sheet can be reduced, and the shape accuracy can be improved.
  • the depth of the center of the cavity portion (distance in the direction corresponding to the thickness direction at the center of the formed optical planar portion; H mid ) in the closed state (closed state) of the mold is 50 ⁇ m or more. It is preferably 100 ⁇ m or more, more preferably 1500 ⁇ m or less, and more preferably 1000 ⁇ m or less.
  • the optical surface portion of the obtained molded sheet can be advantageously used as a transmissive optical element such as a lens.
  • the minimum distance (H min ) between the formed sheet forming surfaces in the closed state is preferably 50 ⁇ m or more, more preferably 100 ⁇ m or more, preferably 500 ⁇ m or less, and preferably 300 ⁇ m. It is more preferably less than or equal to, and even more preferably 200 ⁇ m or less.
  • the minimum interval is not more than the above upper limit value, the variation in the thickness accuracy of the optical surface-shaped portion of the obtained molded sheet can be reduced, and the shape accuracy can be improved. Further, when the minimum interval is not more than the above lower limit value, the strength of the obtained molded sheet can be sufficiently secured.
  • the press temperature (mold temperature) when the thermoplastic resin film is hot-pressed with a pair of molds in the hot pressing process is 40 ° C. higher (Tg + 40 ° C.) or higher than the glass transition temperature (Tg) of the thermoplastic resin.
  • the press temperature is more preferably 50 ° C. higher than the glass transition temperature (Tg + 50 ° C.), and further preferably 55 ° C. higher than the glass transition temperature (Tg + 55 ° C.). ..
  • the press temperature is at least the above lower limit value, the variation in the thickness accuracy of the optical surface-shaped portion of the obtained molded sheet can be reduced, and the shape accuracy can be improved.
  • the press temperature is preferably set to a temperature (Tg + 80 ° C.) or less that is 80 ° C. higher than the glass transition temperature.
  • the press temperature is not particularly limited, and is appropriately adjusted by controlling the temperature of the die according to a known general method (for example, a temperature control method using a known heater and cooler). Can be done.
  • the press pressure at the time of hot pressing the thermoplastic resin film with the die is increased to the final press pressure at a predetermined pressurizing rate, and then arbitrarily held at the final press pressure for a predetermined time.
  • the average pressurizing rate of the press pressure is preferably 0.1 MPa / sec or less, more preferably 0.07 MPa / sec or less, and further preferably 0.05 MPa / sec or less.
  • the average step-up speed is not more than the above upper limit value, the birefringence of the optical surface portion of the obtained molded sheet can be reduced and the shape accuracy can be improved.
  • the average step-up rate is preferably 0.04 MPa / sec or more.
  • the final press pressure is not particularly limited and can be, for example, 1 MPa or more and 10 MPa or less.
  • the final press pressure is within the above range, the shape accuracy of the optical surface of the obtained molded sheet can be further improved, and the variation in thickness accuracy and birefringence can be further reduced.
  • the pressing time in the heat pressing step is not particularly limited, and can be appropriately determined according to the type and size of the thermoplastic resin film to be used, the shape and size of the target molded sheet, and the like.
  • the time for increasing the press pressure to the final press pressure can be 20 seconds or more and 300 seconds or less, and the time for holding the press pressure at the final press pressure can be 0 seconds or more and 180 seconds or less.
  • the mold release step when the molding sheet obtained in the heat pressing step is released from the pair of dies, the temperature of the pair of dies is (Tg-80) ° C. or higher (Tg-15) ° C. or lower (hereinafter, The mold is released at (sometimes referred to as "release temperature").
  • the starting point of the mold release process is, for example, a time when a predetermined time elapses from the start time of the heat pressing process, a time when temperature control for cooling the die is started, or a time after a predetermined time elapses from the start time of the heat pressing process. , It may be the time when the heat input to the mold is stopped.
  • the mold release temperature needs to be equal to or lower than the glass transition temperature (Tg) of the thermoplastic resin, preferably 15 ° C. lower than the glass transition temperature (Tg-15 ° C.), and 20 ° C. lower than the glass transition temperature. It is more preferably (Tg-20 ° C.) or lower, and further preferably 30 ° C. lower than the glass transition temperature (Tg-30 ° C.) or lower.
  • the mold release temperature is preferably 80 ° C. lower than the glass transition temperature (Tg-80 ° C.) or higher, and 75 ° C. lower than the glass transition temperature (Tg-75 ° C.) or higher. preferable.
  • the mold release temperature is not more than the above upper limit value, it is easy to release the mold, and the shape accuracy of the optical surface-shaped portion of the obtained molded sheet can be effectively improved. Further, when the mold release temperature is not more than the above upper limit value, the variation in the thickness accuracy of the optical surface portion of the obtained molded sheet can be reduced, and the birefringence can be reduced. Furthermore, when the mold release temperature is not more than the above upper limit value, it is possible to suppress the occurrence of troubles at the time of mold release and further improve the production efficiency of the molded sheet.
  • the temperature adjustment time required for cooling the pair of dies and raising the temperature in the subsequent heat pressing step can be shortened, and the manufacturing efficiency of the molded sheet can be improved. It can be further enhanced.
  • the time required to cool the mold to the mold release temperature (mold cooling time), the mold cooling rate, etc. are not particularly limited, and the type and size of the sheet-fed sheet material, the target molded sheet, and the like are not particularly limited. It can be appropriately determined according to the shape and size of the optical surface portion.
  • 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.
  • the hot press film is released from the mold to obtain a molded sheet.
  • the method for manufacturing an optical element of the present invention is to separate a molded sheet obtained according to the manufacturing method of the present invention at a position corresponding to each of a plurality of optical planar portions to obtain a plurality of optical elements. It is characterized by including a process. According to the manufacturing method of the present invention, it is possible to easily manufacture an optical element having sufficiently high shape accuracy, small variation in thickness accuracy, and sufficiently small birefringence.
  • optical element separation process a plurality of optical elements are separated from the molded sheet obtained according to the manufacturing method of the present invention.
  • the separation method is not particularly limited, and each optical element can be separated from the molded sheet by any known method such as punching with a punching die or laser cutting.
  • 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 glass transition temperature of the thermoplastic resin was measured as follows.
  • the shape accuracy, the variation in thickness accuracy and the phase difference of the optical surface portion of the molded sheet, and the productivity of the molded sheet were evaluated as follows.
  • Various operations from placement to mold release in Examples and Comparative Examples were all carried out under normal pressure, that is, under conditions where the inside of the mold was not pressurized or depressurized.
  • thermoplastic resin ⁇ Glass transition temperature of thermoplastic resin>
  • the glass transition temperature (Tg) of the thermoplastic resin was measured using a differential scanning calorimeter (“DSC6220” manufactured by Hitachi High-Tech Science Co., Ltd.) under the condition of a heating rate of 10 ° C./min based on JIS K7121: 2012. ..
  • the optical surface of the molded sheet was punched out to obtain an optical lens, which was used as a measurement sample.
  • the optical lenses obtained according to Examples and Comparative Examples were aspherical lenses having an aspherical shape having an inflection point in the cross-sectional shape along the thickness direction of the optical lens, respectively, on the front surface and the back surface.
  • a shape measuring instrument manufactured by Panasonic, "UA-3P" was used to obtain PV values (reference surface) based on the design value of the optical surface.
  • the maximum error of the surface shape of the measurement sample that is, the difference between the highest point (Peek) and the lowest point (Valley) within the measurement range) was measured.
  • the simple average value of the measured PV values was evaluated as the shape accuracy according to the following criteria.
  • the optical surface of the molded sheet was punched out to obtain an optical lens, which was used as a measurement sample.
  • the thickness of the center of 300 measurement samples of the obtained optical lenses was measured using a shape measuring device (“UA-3P” manufactured by Panasonic Corporation).
  • the standard deviation of the measured thickness was evaluated as a variation in thickness accuracy according to the following criteria.
  • Phase difference> The optical surface of the molded sheet was punched out to obtain an optical lens, which was used as a measurement sample.
  • the phase difference of 300 measurement samples of the obtained optical lenses was measured using a resin molded lens inspection system (“WPA-100” manufactured by Photonics Lattice Co., Ltd.). The evaluation was made according to the following criteria using the simple average value of the phase difference values obtained as the values standardized at the measurement wavelength (543 nm).
  • phase difference value The smaller the phase difference value, the smaller the birefringence.
  • thermoplastic resin film thus obtained was cut into 250 mm squares and used as a single-wafer-shaped sheet material.
  • the sheet-fed sheet material obtained according to the above was set in a heat press molding machine equipped with a pair of 300 mm square dies having a temperature control device (arrangement operation). As the pair of molds, those having the properties shown in Table 1 were used. Then, after raising the temperature of the die to the press temperature shown in Table 1, the sheet-fed sheet material was hot-pressed under the conditions shown in Table 1 while increasing the pressure to 9.5 MPa at a step-up rate of 0.045 MPa / sec. (Hot press process). Further, while the single-wafer-shaped sheet material was still pressed, the pair of dies were cooled to 100 ° C.
  • the diameter of the optical surface portion of the molded sheet corresponds to the diameter D of the cavity portion in the mold
  • the minimum distance between the optical surface portions corresponds to the minimum distance P of the cavity portion in the mold.
  • the arrangement density of the cavity corresponds to the arrangement density of the cavity in the mold
  • the thickness of the center of the optical surface corresponds to the depth H mid of the center of the cavity in the closed state
  • the thinnest part of the molded sheet Corresponds to the minimum distance H min between the molded sheet forming surfaces in the closed state.
  • Examples 2 to 4 A molded sheet was produced in the same manner as in Example 1 except that the pair of dies were changed to the dies having the properties shown in Table 1, and various evaluations were performed. The results are shown in Table 1.
  • Examples 5 to 7 A molded sheet was produced in the same manner as in Example 1 except that the mold release temperature in the mold release step was changed to the temperature shown in Table 1, and various evaluations were performed. The results are shown in Table 1.
  • Example 8 A molded sheet was produced in the same manner as in Example 1 except that a sheet material cut into a 400 mm square was used, and various evaluations were performed. The results are shown in Table 1. In the heat pressing process according to this embodiment, the edges of the sheet-fed sheet material protruded from the pair of dies.
  • thermoplastic resin film a thermoplastic resin containing a norbornene-ethylene random copolymer obtained by random addition polymerization using norbornene and ethylene as monomers (TOPAS6013 (manufactured by Polyplastics), glass transition temperature: 138 ° C.) was used.
  • a molded sheet was produced in the same manner as in Example 1 except that the press temperature was changed to the temperature shown in Table 1, and various evaluations were performed. The results are shown in Table 1.
  • Example 10 Polycarbonate resin (Wonderlight PC-115 (manufactured by Asahi Kasei Co., Ltd.), glass transition temperature: 145 ° C.) was used as the thermoplastic resin film, and the press temperature was changed to the temperature shown in Table 1 in the same manner as in Example 1. A molded sheet was manufactured and various evaluations were performed. The results are shown in Table 1.
  • Example 11 Polymethylmethacrylate resin (Delpet 80NH (manufactured by Asahi Kasei Chemicals Co., Ltd.), glass transition temperature: 100 ° C.) was used as the thermoplastic resin film, and the same as in Example 1 except that the press temperature was changed to the temperature shown in Table 1. The molded sheet was manufactured and various evaluations were performed. The results are shown in Table 1.
  • Example 12 A polyester resin (OKP-1 (manufactured by Osaka Gas Chemical Co., Ltd.), glass transition temperature: 132 ° C.) was used as the thermoplastic resin film, and the press temperature was changed to the temperature shown in Table 1 in the same manner as in Example 1. A molded sheet was manufactured and various evaluations were performed. The results are shown in Table 1.
  • Example 1 A molded sheet was produced in the same manner as in Example 1 except that the pair of dies were changed to the dies having the properties shown in Table 1, and various evaluations were performed. The results are shown in Table 1.
  • Example 2 The hot press molding machine equipped with a pair of 300 mm square dies was changed to a hot press molding machine equipped with four pairs of 100 mm square dies in a 2 ⁇ 2 arrangement mode in which the distance between the dies was set to 20 mm.
  • the molded sheets of Examples 1 to 12 have a plurality of optical planar portions having sufficiently high shape accuracy, small variation in thickness accuracy, and sufficiently small birefringence. Further, it can be seen that the molded sheets of Examples 1 to 12 were excellent in continuous productivity. Further, it can be seen that the molded sheet of Comparative Example 1 had low shape accuracy of the optical surface-like portion, large variation in thickness accuracy, and large birefringence. Further, it can be seen that the molded sheet of Comparative Example 1 was poor in continuous productivity.
  • a molded sheet having a plurality of optical planar portions which has sufficiently high shape accuracy, small variation in thickness accuracy, and low birefringence. Further, according to the present invention, it is possible to provide a method for producing a molded sheet capable of efficiently producing the molded sheet. Further, according to the present invention, it is possible to provide a method for manufacturing an optical element using the above-mentioned molded sheet.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Ophthalmology & Optometry (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)

Abstract

A method for manufacturing a molded sheet, the method including a hot-pressing step for obtaining a molded sheet by hot-press molding a sheet-form sheet material comprising a thermoplastic resin film at normal pressure using a pair of dies having a plurality of optical surface formation regions separated from each other.

Description

成形シート及び成形シートの製造方法、並びに、光学素子の製造方法A method for manufacturing a molded sheet and a molded sheet, and a method for manufacturing an optical element.
　本発明は、成形シート及び成形シートの製造方法、並びに、光学素子の製造方法に関する。かかる成形シート及び成形シートの製造方法、並びに、光学素子の製造方法は、透過型光学素子の製造に有用である。 The present invention relates to a molded sheet, a method for manufacturing a molded sheet, and a method for manufacturing an optical element. Such a molding sheet, a method for manufacturing a molded sheet, and a method for manufacturing an optical element are useful for manufacturing a transmission type optical element.
　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. Further, in the lens obtained according to the injection molding method, birefringence was likely to occur. 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、樹脂シートの平面方向に複数の型を配列して、複数のレンズ部について同時に型成形する方法が開示されている。より具体的には、特許文献１には、金属等からなる複数の雌形の下型の上に、樹脂シートを位置決めされた状態で載置して、金属等からなる複数の雄形の上型を押し付けることにより、樹脂シートを塑性変形させて、複数のレンズ部を同時に型成形する方法が開示されている。 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 of arranging a plurality of molds in the plane direction of a resin sheet and simultaneously molding a plurality of lens portions. More specifically, in Patent Document 1, a resin sheet is placed on a plurality of female lower molds made of metal or the like in a positioned state, and on a plurality of male shapes made of metal or the like. A method of plastically deforming a resin sheet by pressing a mold to mold a plurality of lens portions at the same time is disclosed.
国際公開第２０００／０１２２９１号International Publication No. 2000/012291
　しかし、樹脂シートの平面方向に複数の型を配列し、複数のレンズ部について同時に型成形を行うことを特徴とする上記従来の技術では、例えばレンズ等として使用し得る光学面状部を複数有する成形シートを製造した際に、形状精度が十分に高く、厚み精度のバラツキが小さく、且つ、低複屈折性の、複数の光学面状部を有する成形シートを効率的に製造することができなかった。 However, in the above-mentioned conventional technique characterized in that a plurality of molds are arranged in the plane direction of the resin sheet and the plurality of lens portions are simultaneously molded, the resin sheet has a plurality of optical planar portions that can be used as, for example, a lens or the like. When a molded sheet is manufactured, it is not possible to efficiently manufacture a molded sheet having a plurality of optical planar portions, which has sufficiently high shape accuracy, small variation in thickness accuracy, and low birefringence. rice field.
　そこで、本発明は、形状精度が十分に高く、厚み精度のバラツキが小さく、且つ、低複屈折性の、複数の光学面状部を有する成形シートを提供することを目的とする。
　また、本発明は、上記成形シートを効率的に製造することができる成形シートの製造方法を提供することを目的とする。
　さらに、本発明は、上記成形シートを用いた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 molded sheet having a plurality of optical planar portions, which has sufficiently high shape accuracy, small variation in thickness accuracy, and low birefringence.
Another object of the present invention is to provide a method for producing a molded sheet capable of efficiently producing the molded sheet.
A further object of the present invention is to provide a method for manufacturing an optical element using the molded sheet.
　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。そして、本発明者らは、熱可塑性樹脂フィルムよりなる枚葉状のシート材料を、所定の条件で熱プレス成形することにより、形状精度が十分に高く、厚み精度のバラツキが小さく、且つ、低複屈折性の、複数の光学面状部を有する成形シートを提供しうることを見出し、本発明を完成させた。 The present inventors have conducted diligent studies to achieve the above object. Then, the present inventors have sufficiently high shape accuracy, small variation in thickness accuracy, and low birefringence by hot-press molding a sheet-fed sheet material made of a thermoplastic resin film under predetermined conditions. The present invention has been completed by finding that it is possible to provide a molded sheet having a plurality of optically planar parts having refractive properties.
　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、本発明の成形シートの製造方法は、熱可塑性樹脂を用いて形成された熱可塑性樹脂フィルムを熱プレス成型して、複数の光学面状部を有する成形シートを製造する、成形シートの製造方法であって、前記熱可塑性樹脂フィルムよりなる枚葉状のシート材料を、互いに離隔した複数の光学面形成領域を有する一対の金型を用いて常圧下で熱プレス成形して成形シートを得る熱プレス工程を含む、ことを特徴とする。このように、枚葉状のシート材料を、互いに離隔した複数の光学面形成領域を有する一対の金型を用いて常圧下で熱プレス成形すれば、形状精度が十分に高く、厚み精度のバラツキが小さく、且つ、低複屈折性の、複数の光学面状部を有する成形シートを容易に製造することができる。
　なお、本明細書において、シート材料が「枚葉状」であることは、シート材料が所定の大きさに裁断され、且つ、巻き取り状態ではないことを意味する。
　また、本明細書において、「常圧」とは、ある地点において、加圧及び減圧を行わない場合の気圧であり、通常、その地点における大気圧に等しい気圧である。より具体的には、「常圧」とは、ＪＩＳ Ｚ８７０３：１９８３に規定された標準状態における圧力範囲であって、気圧８６ｋＰａ以上１０６ｋＰａ以下の範囲内であることをいう。 That is, the present invention aims to advantageously solve the above problems, and the method for producing a molded sheet of the present invention is to heat-press mold a thermoplastic resin film formed using a thermoplastic resin. A method for producing a molded sheet, which comprises producing a molded sheet having a plurality of optical surface-like portions, wherein the sheet-fed sheet material made of the thermoplastic resin film has a plurality of optical surface forming regions separated from each other. It is characterized by including a hot press step of obtaining a molded sheet by hot press molding under normal pressure using a pair of dies. In this way, if the sheet-fed sheet material is hot-press molded under normal pressure using a pair of dies having a plurality of optical surface forming regions separated from each other, the shape accuracy is sufficiently high and the thickness accuracy varies. It is possible to easily manufacture a molded sheet having a plurality of optical planar portions, which is small and has low birefringence.
In the present specification, the fact that the sheet material is "single-leaf" means that the sheet material is cut to a predetermined size and is not in a wound state.
Further, in the present specification, the "normal pressure" is a pressure pressure when pressurization and depressurization are not performed at a certain point, and is usually a pressure equal to the atmospheric pressure at that point. More specifically, "normal pressure" means the pressure range in the standard state defined in JIS Z8703: 1983, which is within the range of atmospheric pressure of 86 kPa or more and 106 kPa or less.
　ここで、本発明の成形シートの製造方法は、前記熱可塑性樹脂のガラス転移温度をＴｇ（℃）として、前記熱プレス工程にて得た成形シートを前記一対の金型から離型する際に、前記一対の金型を（Ｔｇ－８０）℃以上（Ｔｇ－１５）℃以下の温度にて離型する、離型工程を含むことが好ましい。かかる所定の温度範囲における離型工程を実施することで、得られる成形シートに含まれる複数の光学面状部の形状精度を一層高め、厚み精度のバラツキを一層小さくし、さらには、複屈折を一層小さくすることができる。
　なお、本発明において、「熱可塑性樹脂のガラス転移温度」は、ＪＩＳ Ｋ７１２１：２０１２に基づき測定することができる。 Here, the method for producing a molded sheet of the present invention sets the glass transition temperature of the thermoplastic resin to Tg (° C.), and when the molded sheet obtained in the heat pressing step is released from the pair of dies. It is preferable to include a mold removal step of releasing the pair of molds at a temperature of (Tg-80) ° C. or higher (Tg-15) ° C. or lower. By carrying out the mold release step in such a predetermined temperature range, the shape accuracy of the plurality of optical surface-like portions contained in the obtained molded sheet is further improved, the variation in thickness accuracy is further reduced, and birefringence is further achieved. It can be made even smaller.
In the present invention, the "glass transition temperature of the thermoplastic resin" can be measured based on JIS K7121: 2012.
　さらに、本発明の成形シートの製造方法は、前記熱プレス工程にて、前記一対の金型により前記枚葉状のシート材料をプレスした状態で、前記枚葉状のシート材料が、前記一対の金型からはみ出さないことが好ましい。プレス状態において枚葉状のシート材料が一対の金型からはみ出さないようにすることで、得られる成形シートに含まれる複数の光学面状部の形状精度を一層高め、厚み精度のバラツキを一層小さくし、複屈折を一層小さくすることができ、さらに、成形シートの生産効率を高めることができる。 Further, in the method for producing a molded sheet of the present invention, in the heat pressing step, the sheet-fed sheet material is pressed by the pair of dies, and the sheet-fed sheet material is used as the pair of dies. It is preferable that it does not stick out. By preventing the sheet-fed sheet material from protruding from the pair of dies in the pressed state, the shape accuracy of the plurality of optical surface-like parts contained in the obtained molded sheet is further improved, and the variation in thickness accuracy is further reduced. However, the birefringence can be further reduced, and the production efficiency of the molded sheet can be improved.
　そして、本発明の成形シートの製造方法において、前記熱可塑性樹脂が脂環式構造含有樹脂であることが好ましい。熱可塑性樹脂が脂環式構造含有樹脂であれば、得られる成形シートに含まれる複数の光学面状部の形状精度を一層高め、厚み精度のバラツキを一層小さくし、さらに、成形シートの生産効率を高めることができる。 Then, in the method for producing a molded sheet of the present invention, it is preferable that the thermoplastic resin is an alicyclic structure-containing resin. If the thermoplastic resin is an alicyclic structure-containing resin, the shape accuracy of a plurality of optical surface-like portions contained in the obtained molded sheet can be further improved, the variation in thickness accuracy can be further reduced, and the production efficiency of the molded sheet can be further reduced. Can be enhanced.
　また、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、本発明の光学素子の製造方法は、上述した何れかの成形シートの製造方法に従って得られた成形シートを、前記複数の光学面状部のそれぞれに対応する位置で分離して、複数の光学素子を得ることを特徴とする。かかる本発明の製造方法によれば、形状精度が十分に高く、厚み精度のバラツキが小さく、且つ、複屈折が十分に小さい光学素子を、容易に製造することができる。 The present invention also aims to advantageously solve the above problems, and the method for manufacturing an optical element of the present invention is to obtain a molded sheet according to any of the above-mentioned molding sheet manufacturing methods. It is characterized in that a plurality of optical elements are obtained by separating the plurality of optical surface-shaped portions at positions corresponding to each of them. According to the manufacturing method of the present invention, it is possible to easily manufacture an optical element having sufficiently high shape accuracy, small variation in thickness accuracy, and sufficiently small birefringence.
　また、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、本発明の成形シートは、熱可塑性樹脂を用いて形成された、光学面状部を複数有する、枚葉状の成形シートであって、前記光学面状部の配設密度が０．１６個／ｃｍ２以上であり、互いに隣接する光学面状部間の最小間隔が１．０ｍｍ以上であり、平面視における前記光学面状部の直径が１ｍｍ以上１５ｍｍ以下であり、前記光学面状部の位相差が５０ｎｍ以下であり、前記光学面状部の厚み精度のバラツキが０．２μｍ以下であることを特徴とする。このように、成形シートにおける光学面状部の配設密度、最小間隔、直径、位相差、及び厚み精度のバラツキが所定の範囲内であれば、かかる成型シートの光学面状部は形状精度に優れる。さらに、かかる成形シートを用いることで、光学性能に優れる光学素子を効率的に製造することができる。
　なお、「位相差」及び「厚み精度のバラツキ」は、実施例に記載の方法を用いて評価又は測定することができる。 The present invention also aims to advantageously solve the above problems, and the molded sheet of the present invention is a single-wafer-shaped sheet having a plurality of optical surface-like portions formed by using a thermoplastic resin. In the molded sheet, the arrangement density of the optical planar portions is 0.16 pieces / cm 2 or more, the minimum distance between the optical planar portions adjacent to each other is 1.0 mm or more, and the above-mentioned in a plan view. The feature is that the diameter of the optical surface portion is 1 mm or more and 15 mm or less, the phase difference of the optical surface portion is 50 nm or less, and the variation in the thickness accuracy of the optical surface portion is 0.2 μm or less. .. As described above, if the arrangement density, the minimum spacing, the diameter, the phase difference, and the thickness accuracy of the optical surface-shaped portion of the molded sheet are within a predetermined range, the optical surface-shaped portion of the molded sheet has a shape accuracy. Excellent. Further, by using such a molded sheet, an optical element having excellent optical performance can be efficiently manufactured.
The "phase difference" and "variation in thickness accuracy" can be evaluated or measured by using the method described in the examples.
　ここで、本発明の成形シートは、前記光学面状部の少なくとも一方の表面は、厚み方向の断面形状が変曲点を有する非球面形状であることが好ましい。このような形状を有する光学面状部は、レンズなどの透過型光学素子として有利に使用し得る。 Here, in the molded sheet of the present invention, it is preferable that at least one surface of the optical surface-like portion has an aspherical shape having an inflection point in the cross-sectional shape in the thickness direction. An optical planar portion having such a shape can be advantageously used as a transmissive optical element such as a lens.
　本発明によれば、形状精度が十分に高く、厚み精度のバラツキが小さく、且つ、低複屈折性の、複数の光学面状部を有する成形シートを提供することができる。
　また、本発明によれば、上記成形シートを効率的に製造することができる成形シートの製造方法を提供することができる。
　さらに、本発明によれば、上記成形シートを用いた光学素子の製造方法を提供することができる。 According to the present invention, it is possible to provide a molded sheet having a plurality of optical planar portions, which has sufficiently high shape accuracy, small variation in thickness accuracy, and low birefringence.
Further, according to the present invention, it is possible to provide a method for producing a molded sheet capable of efficiently producing the molded sheet.
Further, according to the present invention, it is possible to provide a method for manufacturing an optical element using the above-mentioned molded sheet.
本発明の一例に係る成形シートの厚み方向に沿う断面を示す概略断面図である。It is a schematic cross-sectional view which shows the cross section along the thickness direction of the molded sheet which concerns on an example of this invention. 本発明の一例に係る成形シートの製造方法における、熱プレス工程を説明するための概略図である。It is a schematic diagram for demonstrating the heat pressing process in the manufacturing method of the molded sheet which concerns on an example of this invention.
　以下、本発明の実施形態について詳細に説明する。本発明の成形シートの製造方法は、例えば本発明の成形シートを製造する際に用いることができる。また、本発明の光学素子の製造方法は、本発明の成形シートの製造方法に従って得られた成形シートを用いて、光学素子を製造する際に好適に適用することができる。そして、本発明に係る成形シートは、特に限定されることなく、種々の形状の光学面を有する光学素子の製造に好適に用いることができる。ここで、「光学面」とは、光に対して、反射、屈折、及び透過等の光学作用を及ぼし得る界面を意味し、その形状としては、平面、球面、非球面、自由曲面、レンチキュラー、及びフレネル等が挙げられる。また、本発明に係る成形シートを用いて好適に製造し得る「光学素子」としては、光学レンズ及びプリズムといった透過型光学素子が挙げられる。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、光学レンズ以外の、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。本発明に係る成形シートを用いれば、形状精度が高く、且つ、低複屈折性の（即ち、位相差が小さい）透過型光学素子を効率的に得ることができる。特に、本発明に係る成形シートは、種々の形状の光学素子の中でも、片面及び／又は両面が変曲点のある非球面レンズ製造する際に好適に用いることができる。そして、当該非球面レンズは、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。 Hereinafter, embodiments of the present invention will be described in detail. The method for producing a molded sheet of the present invention can be used, for example, when producing the molded sheet of the present invention. In addition, the method for manufacturing an optical element of the present invention can be suitably applied when manufacturing an optical element using a molded sheet obtained according to the method for manufacturing a molded sheet of the present invention. The molded sheet according to the present invention is not particularly limited, and can be suitably used for manufacturing an optical element having optical surfaces having various shapes. Here, the "optical surface" means an interface that can exert optical actions such as reflection, refraction, and transmission on light, and its shape includes a flat surface, a spherical surface, an aspherical surface, a free curved surface, and a lenticular. And Fresnel and the like. Further, examples of the "optical element" that can be suitably manufactured using the molded sheet according to the present invention include a transmission type optical element such as an optical lens and a prism. Here, the "optical lens" means a transparent body that exhibits a refracting action of light. Further, the “prism” means a transparent polyhedron other than an optical lens, which exhibits a light dispersion action, a refraction action, a total reflection action, and / or a birefringence action. By using the molded sheet according to the present invention, it is possible to efficiently obtain a transmissive optical element having high shape accuracy and low birefringence (that is, a small phase difference). In particular, the molded sheet according to the present invention can be suitably used when manufacturing an aspherical lens having inflection points on one side and / or both sides among optical elements having various shapes. Then, the aspherical lens can be suitably used as, for example, a lens of a camera unit of a small electronic electric device.
（成形シート）
　本発明の成形シートは、厚み方向に沿う断面の形状を、例えば図１に示すように、熱可塑性樹脂を用いて形成された枚葉状の成形シート１０であって、光学面状部１１を複数有するものである。そして、本発明の成形シート１０は、光学面状部１１の配設密度が０．１６個／ｃｍ２以上であり、互いに隣接する光学面状部１１間の最小間隔Ｐが１．０ｍｍ以上であり、平面視における光学面状部１１の直径Ｄが１ｍｍ以上１５ｍｍ以下であり、光学面状部１１の位相差が５０ｎｍ以下であり、光学面状部１１の厚み精度のバラツキが０．２μｍ以下であることを必要とする。光学面状部の配設密度、最小間隔、直径及び位相差、並びに、厚み精度のバラツキが上記範囲内であれば、形状精度を高めることができる。さらに、かかる成形シートを用いることで、光学性能に優れる光学素子を効率的に製造することができる。
　なお、成形シートの光学面状部の形状は、図１に示す形状に限定されず、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等、任意の形状とすることができる。そして、成形シートの光学面状部は、特に限定されることなく、例えば成形シートから切り出してレンズとして好適に用いることができる。ここで、レンズなどの透過型光学素子として有利に使用し得る観点からは、光学面状部の少なくとも一方の表面は、厚み方向の断面形状が変曲点を有する形状であることが好ましい。 (Molded sheet)
The molded sheet of the present invention has a cross-sectional shape along the thickness direction, for example, as shown in FIG. 1, is a sheet-fed molded sheet 10 formed by using a thermoplastic resin, and has a plurality of optical surface-like portions 11. Have. In the molded sheet 10 of the present invention, the arrangement density of the optical surface portions 11 is 0.16 pieces / cm 2 or more, and the minimum distance P between the optical surface portions 11 adjacent to each other is 1.0 mm or more. Yes, the diameter D of the optical surface portion 11 in a plan view is 1 mm or more and 15 mm or less, the phase difference of the optical surface portion 11 is 50 nm or less, and the variation in the thickness accuracy of the optical surface portion 11 is 0.2 μm or less. Need to be. If the arrangement density, the minimum spacing, the diameter and the phase difference of the optical surface-like portions, and the variation in the thickness accuracy are within the above ranges, the shape accuracy can be improved. Further, by using such a molded sheet, an optical element having excellent optical performance can be efficiently manufactured.
The shape of the optical surface of the molded sheet is not limited to the shape shown in FIG. 1, and may be any shape such as a plano-convex lens, a biconvex lens, a convex meniscus lens, a plano-concave lens, a biconcave lens, and a concave meniscus lens. be able to. The optical surface of the molded sheet is not particularly limited, and can be suitably used as a lens by cutting out from the molded sheet, for example. Here, from the viewpoint that it can be advantageously used as a transmissive optical element such as a lens, it is preferable that at least one surface of the optical surface portion has an inflection point in the cross-sectional shape in the thickness direction.
＜熱可塑性樹脂＞
　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、得られる成形シートに含まれる複数の光学面状部の形状精度を一層高め、厚み精度のバラツキを一層小さくし、さらに、成形シートの生産効率を高めることができることから、熱可塑性樹脂が脂環構造含有樹脂を含むことが好ましい。また、得られる成形シートが透明性に優れることからも、熱可塑性樹脂が脂環構造含有樹脂を含むことが好ましい。 <Thermoplastic resin>
Examples of the thermoplastic resin include (meth) acrylic resin, alicyclic structure-containing resin, styrene resin, polycarbonate resin, polyester resin, polyether resin, urethane resin, and thiourethane resin. In addition, "(meth) acrylic" refers to acrylic and / or methacryl. 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, the thermoplastic resin can further improve the shape accuracy of the plurality of optical planar parts contained in the obtained molded sheet, further reduce the variation in thickness accuracy, and further improve the production efficiency of the molded sheet. Preferably contains an alicyclic structure-containing resin. Further, since the obtained molded sheet is excellent in transparency, it is preferable that the thermoplastic resin contains an alicyclic structure-containing resin.
　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成形シート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、得られる成形シートに含まれる複数の光学面状部の形状精度を一層高め、厚み精度のバラツキを一層小さくし、さらに、成形シートの生産効率を高めることができる。また、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成形シートが得られ易くなる。 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 a molded sheet having excellent mechanical strength and heat resistance can be easily obtained. 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 proportion of repeating units of 50% by mass or more, the shape accuracy of a plurality of optical surface-like portions contained in the obtained molded sheet is further improved, and the thickness accuracy is further improved. It is possible to further reduce the variation of the molded sheet and further improve the production efficiency of the molded sheet. Further, by using an alicyclic structure-containing polymer having an alicyclic structure and a proportion of repeating units of 50% by mass or more, it becomes easy to obtain a molded sheet 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、得られる成形シートの透明性、耐熱性、及び機械的強度を高める観点、及び、得られる成形シートに含まれる複数の光学面状部の形状精度を一層高め、厚み精度のバラツキを一層小さくし、さらに、成形シートの生産効率を高める観点から、ノルボルネン系重合体が好ましい。また、得られる成形シートに含まれる複数の光学面状部の形状精度を一層高め、厚み精度のバラツキを一層小さくし、さらに、成形シートの生産効率を高めることができることからも、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 norbornene-based polymers, monocyclic cyclic olefin-based polymers, cyclic conjugated diene-based polymers, and vinyl alicyclic hydrocarbon-based polymers. Among these, from the viewpoint of improving the transparency, heat resistance, and mechanical strength of the obtained molded sheet, and further improving the shape accuracy of the plurality of optical planar parts contained in the obtained molded sheet, the thickness accuracy varies. A norbornene-based polymer is preferable from the viewpoint of making it smaller and further increasing the production efficiency of the molded sheet. In addition, the norbornene-based polymer can further improve the shape accuracy of the plurality of optical planar portions contained in the obtained molded sheet, further reduce the variation in thickness accuracy, and further improve the production efficiency of the molded sheet. Is preferable. 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ることで、成形シートの透明性、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、熱プレス成形を用いて成形シート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 the norbornene-based ring-opening polymer hydride, the transparency, heat resistance, mechanical strength, etc. of the molded sheet can be further improved, and the mold can be released when the molded sheet is manufactured by hot press molding. The sex and transferability can be enhanced.
　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 and 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 . 17 and 10 ] Dodeca-3-ene, 8-methyl-8-methoxycarbonyl-tetracyclo [4.4.0.1 2,5 . 17 and 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 ring-opening copolymerizable with norbornene-based monomers 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.
　そして、熱可塑性樹脂のガラス転移温度（Ｔｇ）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。熱可塑性樹脂のガラス転移温度（Ｔｇ）が上記下限値以上であれば、成形シートの光学面状部の形状精度を一層高めることができるとともに、光学面状部の厚み精度のバラツキを小さくすることができ、さらには、成形シートの製造効率を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（Ｔｇ）が上記上限値以下であれば、成形シートの生産効率を高めると共に、光学面状部の形状精度を一層高めることができる。 The glass transition temperature (Tg) of the thermoplastic resin is not particularly limited, but is preferably 100 ° C. or higher, more preferably 120 ° C. or higher, preferably 200 ° C. or lower, and more preferably 160 ° C. or lower. When the glass transition temperature (Tg) of the thermoplastic resin is equal to or higher than the above lower limit value, the shape accuracy of the optical surface portion of the molded sheet can be further improved, and the variation in the thickness accuracy of the optical surface portion can be reduced. Furthermore, it is possible to improve the manufacturing efficiency of the molded sheet. Further, when the glass transition temperature (Tg) of the thermoplastic resin film is not more than the above upper limit value, the production efficiency of the molded sheet can be improved and the shape accuracy of the optical surface portion can be further improved.
　なお、成形シートは、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、赤外線吸収剤、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 molded sheet 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, infrared absorbers, antioxidants, mold release agents, antistatic agents, carbon materials (carbon, etc.), pigments, and dyes. Be done. 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.
＜光学面状部＞
　光学面状部（図１における１１）は、配設密度が０．１６個／ｃｍ２以上であることが必要であり、光学面状部の配設密度は、０．３０個／ｃｍ２以上であることが好ましく、０．４０個／ｃｍ２以上であることがより好ましく、３．０個／ｃｍ２以下であることが好ましく、２．０個／ｃｍ２以下であることがより好ましく、１．０個／ｃｍ２以下であることが更に好ましく、０．６０個／ｃｍ２以下であることが特に好ましい。光学面状部の配設密度が０．１６個／ｃｍ２以上であれば、光学面状部の厚み精度のバラツキを小さくすることができると共に、形状精度を高めることができる。また、光学面状部の配設密度が上記上限値以下であれば、形状精度を高めることができ、且つ、複屈折を小さくすることができると共に、厚み精度のバラつきを更に小さくすることができる。 <Optical surface>
The arrangement density of the optical surface portion (11 in FIG. 1) needs to be 0.16 pieces / cm 2 or more, and the arrangement density of the optical surface part is 0.30 pieces / cm 2 or more. It is preferably 0.40 pieces / cm 2 or more, more preferably 3.0 pieces / cm 2 or less, and more preferably 2.0 pieces / cm 2 or less. It is more preferably 1.0 piece / cm 2 or less, and particularly preferably 0.60 piece / cm 2 or less. When the arrangement density of the optical surface portion is 0.16 pieces / cm 2 or more, the variation in the thickness accuracy of the optical surface portion can be reduced and the shape accuracy can be improved. Further, when the arrangement density of the optical surface portion is not more than the above upper limit value, the shape accuracy can be improved, the birefringence can be reduced, and the variation in the thickness accuracy can be further reduced. ..
　また、互いに隣接する光学面状部間の最小間隔（図１におけるＰ）は、１．０ｍｍ以上であることが必要であり、３．０ｍｍ以上であることが好ましく、５．０ｍｍ以上であることがより好ましく、７．０ｍｍ以上であることが更に好ましい。光学面状部間の最小間隔が１．０ｍｍ以上であれば、光学面状部の厚み精度のバラツキを小さくすることができると共に、形状精度を高めることができ、さらには、複屈折を小さくすることができる。また、光学面状部間の最小間隔が１．０ｍｍ以上であれば、例えばプレス成形等の成形方法を用いて作製する場合であっても、成形シート中の気泡及びエア溜まりの発生を抑制することができる。なお、光学面状部間の最小間隔は、通常、２０ｍｍ以下である。 Further, the minimum distance (P in FIG. 1) between the optical plane portions adjacent to each other needs to be 1.0 mm or more, preferably 3.0 mm or more, and preferably 5.0 mm or more. Is more preferable, and 7.0 mm or more is further preferable. When the minimum distance between the optical surface portions is 1.0 mm or more, the variation in the thickness accuracy of the optical surface portions can be reduced, the shape accuracy can be improved, and the birefringence can be reduced. be able to. Further, if the minimum distance between the optical surface portions is 1.0 mm or more, the generation of air bubbles and air pools in the molded sheet is suppressed even when the molding method such as press molding is used. be able to. The minimum distance between the optical surface portions is usually 20 mm or less.
　更に、平面視における光学面状部の直径（図１におけるＤ）は、１ｍｍ以上１５ｍｍ以下であることが必要であり、光学面状部の直径は、３ｍｍ以上であることが好ましく、９ｍｍ以下であることが好ましい。光学面状部の直径が上記範囲内であれば、光学面状部の厚み精度のバラツキを小さくすることができると共に、形状精度を高めることができる。 Further, the diameter of the optical surface portion (D in FIG. 1) in a plan view needs to be 1 mm or more and 15 mm or less, and the diameter of the optical surface portion is preferably 3 mm or more, preferably 9 mm or less. It is preferable to have. When the diameter of the optical surface portion is within the above range, the variation in the thickness accuracy of the optical surface portion can be reduced and the shape accuracy can be improved.
　また、光学面状部の中心の厚み（図１におけるＨｍｉｄ）は、５０μｍ以上であることが好ましく、１００μｍ以上であることがより好ましく、１５００μｍ以下であることが好ましく、１０００μｍ以下であることがより好ましい。光学面状部の中心の厚みが上記範囲内であれば、レンズなどの透過型光学素子として有利に使用することができる。 The thickness of the center of the optical surface portion (H mid in FIG. 1) is preferably 50 μm or more, more preferably 100 μm or more, preferably 1500 μm or less, and preferably 1000 μm or less. More preferred. When the thickness of the center of the optical surface portion is within the above range, it can be advantageously used as a transmissive optical element such as a lens.
　更に、光学面状部の厚み精度のバラツキは、０．２μｍ以下である必要があり、０．１μｍ以下であることが好ましい。厚み精度のバラツキが上記上限値以下であれば、光学面状部における複屈折を小さくすることができる。 Further, the variation in the thickness accuracy of the optical surface portion needs to be 0.2 μm or less, and is preferably 0.1 μm or less. When the variation in thickness accuracy is not more than the above upper limit value, the birefringence in the optical surface portion can be reduced.
　そして、光学面状部の位相差は、５０ｎｍ以下であることが必要であり、２０ｎｍ以下であることが好ましい。位相差が上記上限値以下であれば、光学面状部における複屈折が十分に小さい。さらに、位相差が上記上限値以下となるようにした場合には、光学面状部の厚み精度のバラツキを小さくすることができると共に、形状精度を高めることができる。 The phase difference of the optical surface portion needs to be 50 nm or less, and preferably 20 nm or less. When the phase difference is not more than the above upper limit value, the birefringence in the optical surface portion is sufficiently small. Further, when the phase difference is set to be equal to or less than the above upper limit value, the variation in the thickness accuracy of the optical surface portion can be reduced and the shape accuracy can be improved.
　ここで、成形シートは、最薄部（図１におけるＨｍｉｎ）の厚みが、５０μｍ以上であることが好ましく、１００μｍ以上であることがより好ましく、５００μｍ以下であることが好ましく、３００μｍ以下であることがより好ましく、２００μｍ以下であることがさらに好ましい。最薄部の厚みが上記上限値以下であれば、光学面状部の厚み精度のバラツキを小さくすることができると共に、形状精度を高めることができる。また、最薄部の厚みが上記下限値以上であれば、成形シートの強度を十分に高めることができる。 Here, the thickness of the thinnest portion (H min in FIG. 1) of the molded sheet is preferably 50 μm or more, more preferably 100 μm or more, preferably 500 μm or less, and preferably 300 μm or less. More preferably, it is more preferably 200 μm or less. When the thickness of the thinnest portion is equal to or less than the above upper limit value, the variation in the thickness accuracy of the optical surface portion can be reduced and the shape accuracy can be improved. Further, when the thickness of the thinnest portion is at least the above lower limit value, the strength of the molded sheet can be sufficiently increased.
（成形シートの製造方法）
　本発明の成形シートの製造方法は、熱可塑性樹脂を用いて形成された熱可塑性樹脂フィルムを熱プレス成型して、複数の光学面状部を有する成形シートを製造する方法であり、特に限定されることなく、例えば上述した本発明の成形シートを製造する際に用いることができる。そして、本発明の成形シートの製造方法は、熱可塑性樹脂フィルムよりなる枚葉状のシート材料を、互いに離隔した複数の光学面形成領域を有する一対の金型を用いて常圧下で熱プレス成形して成形シートを得る「熱プレス工程」を含むことを特徴とする。さらに、本発明の成形シートの製造方法は、熱プレス工程にて得た成形シートを一対の金型から離型する「離型工程」を含むことが好ましい。本発明の成形シートの製造方法では、「熱プレス工程」にて、枚葉状のシート材料を、互いに離隔した複数の光学面形成領域を有する一対の金型を用いて常圧下で熱プレス成形するため、形状精度が十分に高く、厚み精度のバラツキが小さく、且つ、複屈折が十分に小さい、複数の光学面状部を有する成形シートを容易に製造することができる。 (Manufacturing method of molded sheet)
The method for producing a molded sheet of the present invention is a method for producing a molded sheet having a plurality of optical planar portions by hot-press molding a thermoplastic resin film formed using a thermoplastic resin, and is particularly limited. It can be used, for example, when producing the molded sheet of the present invention described above. Then, in the method for producing a molded sheet of the present invention, a sheet-fed sheet material made of a thermoplastic resin film is hot-press molded under normal pressure using a pair of dies having a plurality of optical surface forming regions separated from each other. It is characterized by including a "heat pressing process" for obtaining a molded sheet. Further, the method for producing a molded sheet of the present invention preferably includes a "mold release step" in which a molded sheet obtained in a hot pressing step is released from a pair of dies. In the method for producing a molded sheet of the present invention, in a "hot pressing step", a sheet-fed sheet material is hot-press molded under normal pressure using a pair of dies having a plurality of optical surface forming regions separated from each other. Therefore, it is possible to easily manufacture a molded sheet having a plurality of optical planar portions, which has sufficiently high shape accuracy, small variation in thickness accuracy, and sufficiently small birefringence.
＜成形シート＞
　本発明の成形シートの製造方法で製造する成形シートは、互いに離隔した複数の光学面状部を有する枚葉状のシートであれば特に限定されない。中でも、成形シートは、上述した本発明の成形シートと同様の性状を有していることが好ましい。 <Molded sheet>
The molded sheet produced by the method for producing a molded sheet of the present invention is not particularly limited as long as it is a single-wafer-shaped sheet having a plurality of optical plane-like portions separated from each other. Above all, it is preferable that the molded sheet has the same properties as the molded sheet of the present invention described above.
＜熱可塑性樹脂フィルム＞
　熱可塑性樹脂フィルムに用いられる熱可塑性樹脂としては、特に限定されることなく、例えば上述した本発明の成形シートの熱可塑性樹脂と同様のものが挙げられる。なお、「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。 <Thermoplastic resin film>
The thermoplastic resin used for the thermoplastic resin film is not particularly limited, and examples thereof include the same thermoplastic resin as the above-mentioned molded sheet of the present invention. 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.
　そして、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た後、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 producing a thermoplastic resin film, and then the thermoplastic resin film is produced by a melt extrusion molding method, a melt casting method, an injection molding method, or the like. Obtainable.
　熱可塑性樹脂フィルムの厚みは、製造する成形シートの光学面状部の直径に応じて、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の厚みにバラツキがある場合には、熱可塑性樹脂フィルムの厚みは、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 optical surface of the molded sheet 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 a simple arithmetic mean value of the thicknesses at a plurality of randomly selected measurement points.
　そして、熱可塑性樹脂フィルムを、例えば、Ａ４サイズ～５０ｃｍ×５０ｃｍサイズ等の所望のサイズに切り出して、枚葉状のシート材料とすることができる。 Then, the thermoplastic resin film can be cut into a desired size such as A4 size to 50 cm × 50 cm size to obtain a single-wafer-shaped sheet material.
＜熱プレス工程＞
　熱プレス工程では、熱可塑性樹脂フィルムよりなる枚葉状のシート材料を、互いに離隔した複数の光学面形成領域を有する一対の金型を用いて常圧下で熱プレス成形する。なお、熱プレス工程を開始するにあたり、枚葉状のシート材料を熱プレス装置にセットする配置操作を実施し得る。図２に、本発明の一例に係る成形シートの製造方法における、熱プレス工程を説明するための概略図を示す。図２に示すように、本例に係る熱プレス工程では、枚葉状のシート材料１０’を、上側金型１Ａ及び下側金型１Ｂより成る一対の金型１を用いて熱プレスする。そして、図２の下図に示すように、一対の金型１により枚葉状のシート材料１０’をプレスした状態で、枚葉状のシート材料１０’が、一対の金型１からはみ出さないことが好ましい。プレス状態において枚葉状のシート材料１０’が一対の金型１からはみ出さないようにすることで、得られる成形シートに含まれる複数の光学面状部の形状精度を一層高め、厚み精度のバラツキを一層小さくし、さらには、複屈折を一層小さくすることができ、さらに、成形シートの生産効率を高めることができる。なお、本発明の成形シート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金型を用いた熱プレスに供することで、得られる成形シートの光学面状部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 press step, a sheet-fed sheet material made of a thermoplastic resin film is hot press molded under normal pressure using a pair of dies having a plurality of optical surface forming regions separated from each other. At the start of the heat pressing process, an arrangement operation of setting the sheet material in a sheet-fed shape in the heat pressing apparatus can be performed. FIG. 2 shows a schematic view for explaining a heat pressing process in the method for producing a molded sheet according to an example of the present invention. As shown in FIG. 2, in the heat pressing step according to this example, the sheet-fed sheet material 10'is heat-pressed using a pair of dies 1 composed of an upper die 1A and a lower die 1B. Then, as shown in the lower part of FIG. 2, in a state where the single-wafer-shaped sheet material 10'is pressed by the pair of dies 1, the single-wafer-shaped sheet material 10'does not protrude from the pair of dies 1. preferable. By preventing the sheet-fed sheet material 10'from protruding from the pair of dies 1 in the pressed state, the shape accuracy of the plurality of optical surface-like portions contained in the obtained molded sheet is further improved, and the thickness accuracy varies. Further, the birefringence can be further reduced, and the production efficiency of the molded sheet can be improved. In the method for producing a molded sheet of the present invention, birefringence occurs in the optical surface of the obtained molded sheet by subjecting the thermoplastic resin film to a hot press using a mold regardless of the injection molding method. Can be suppressed.
［金型］
　一対の金型１としては、少なくとも一方が光学面状部形成領域であるキャビティ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、平板金型などの任意の形状の金型を用い得る。
　なお、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]
The pair of molds 1 is not particularly limited as long as at least one of them has a plurality of cavity portions which are optical surface-shaped portions forming regions, and a mold having an arbitrary shape such as a flat plate mold is used. obtain.
As the material used for the mold, a known material can be used. Examples thereof include carbon steel, stainless steel, and alloys based on these. Among them, stainless steel such as STAVAX (registered trademark) material (manufactured by Uddeholms) 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.
　そして、本発明の製造方法で用いる金型の少なくとも一方は、複数のキャビティ部が金型の平面方向にて離散配置されてなる。複数のキャビティ部は、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。
　ここで、一対の金型は、両方が、それぞれ複数のキャビティ部を有していてもよい。キャビティ部をそれぞれ有する一対の金型を用いて成形することで、両面が賦形された成形シートを効率的に製造することができるからである。なお、一対の金型の各形状は、当然、製造する成形シートの形状に応じて、同一であっても、相異なっていても良い。 Then, at least one of the molds used in the manufacturing method of the present invention has a plurality of cavity portions discretely arranged in the plane direction of the mold. It is preferable that the plurality of cavities are arranged at equal intervals in the plane direction of the mold.
Here, both of the pair of molds may have a plurality of cavities. This is because a molded sheet having both sides shaped can be efficiently manufactured by molding using a pair of dies each having a cavity portion. Of course, the shapes of the pair of dies may be the same or different depending on the shape of the molded sheet to be manufactured.
　キャビティ部は、配設密度が０．１６個／ｃｍ２以上であることが好ましく、０．３０個／ｃｍ２以上であることがより好ましく、０．４０個／ｃｍ２以上であることが更に好ましく、３．０個／ｃｍ２以下であることが好ましく、２．０個／ｃｍ２以下であることがより好ましく、１．０個／ｃｍ２以下であることが更に好ましく、０．６０個／ｃｍ２以下であることが特に好ましい。キャビティ部の配設密度が０．１６個／ｃｍ２以上であれば、得られる成形シートの光学面状部の厚み精度のバラツキを小さくすることができると共に、形状精度を高めることができる。また、キャビティ部の配設密度が上記上限値以下であれば、得られる成形シートにおける形状精度を高めることができ、且つ、複屈折を小さくすることができると共に、厚み精度のバラつきを更に小さくすることができる。 The cavity portion preferably has an arrangement density of 0.16 pieces / cm 2 or more, more preferably 0.30 pieces / cm 2 or more, and further preferably 0.40 pieces / cm 2 or more. Preferably, it is 3.0 pieces / cm 2 or less, more preferably 2.0 pieces / cm 2 or less, further preferably 1.0 piece / cm 2 or less, and 0.60 pieces. It is particularly preferable that it is / cm 2 or less. When the arrangement density of the cavity portion is 0.16 pieces / cm 2 or more, the variation in the thickness accuracy of the optical surface-shaped portion of the obtained molded sheet can be reduced, and the shape accuracy can be improved. Further, when the arrangement density of the cavity portion is not more than the above upper limit value, the shape accuracy of the obtained molded sheet can be improved, the birefringence can be reduced, and the variation in thickness accuracy can be further reduced. be able to.
　また、互いに隣接するキャビティ部間の最小間隔（図１におけるＰに相当）は、１．０ｍｍ以上であることが好ましく、３．０ｍｍ以上であることがより好ましく、５．０ｍｍ以上であることが更に好ましく、７．０ｍｍ以上であることが特に好ましい。キャビティ部間の最小間隔（Ｐ）が１．０ｍｍ以上であれば、得られる成形シートの光学面状部の厚み精度のバラツキを小さくすることができると共に、形状精度を高めることができ、さらには、複屈折を小さくすることができ。また、キャビティ部の最小間隔が１．０ｍｍ以上であれば、成形シート中の気泡及びエア溜まりの発生を抑制することができる。なお、キャビティ部間の最小間隔は、通常、２０ｍｍ以下である。 The minimum distance between the cavities adjacent to each other (corresponding to P in FIG. 1) is preferably 1.0 mm or more, more preferably 3.0 mm or more, and preferably 5.0 mm or more. It is more preferably 7.0 mm or more, and particularly preferably 7.0 mm or more. When the minimum distance (P) between the cavities is 1.0 mm or more, the variation in the thickness accuracy of the optical surface portion of the obtained molded sheet can be reduced, the shape accuracy can be improved, and further, the shape accuracy can be improved. , Birefringence can be reduced. Further, when the minimum distance between the cavities is 1.0 mm or more, it is possible to suppress the generation of air bubbles and air pools in the molded sheet. The minimum distance between the cavities is usually 20 mm or less.
　更に、平面視におけるキャビティ部の直径（図１におけるＤに相当）は、１ｍｍ以上１５ｍｍ以下であることが好ましく、３ｍｍ以上であることがより好ましく、９ｍｍ以下であることが好ましい。キャビティ部の直径が上記範囲内であれば、得られる成形シートの光学面状部の厚み精度のバラツキを小さくすることができると共に、形状精度を高めることができる。 Further, the diameter of the cavity portion (corresponding to D in FIG. 1) in a plan view is preferably 1 mm or more and 15 mm or less, more preferably 3 mm or more, and preferably 9 mm or less. When the diameter of the cavity portion is within the above range, the variation in the thickness accuracy of the optical surface-shaped portion of the obtained molded sheet can be reduced, and the shape accuracy can be improved.
　また、金型を閉じた状態（閉型状態）におけるキャビティ部の中心の深さ（形成される光学面状部の中心における、厚み方向に対応する方向の距離；Ｈｍｉｄ）は、５０μｍ以上であることが好ましく、１００μｍ以上であることがより好ましく、１５００μｍ以下であることが好ましく、１０００μｍ以下であることがより好ましい。キャビティ部の中心の深さが上記範囲内であれば、得られる成形シートの光学面状部をレンズなどの透過型光学素子として有利に使用することができる。 Further, the depth of the center of the cavity portion (distance in the direction corresponding to the thickness direction at the center of the formed optical planar portion; H mid ) in the closed state (closed state) of the mold is 50 μm or more. It is preferably 100 μm or more, more preferably 1500 μm or less, and more preferably 1000 μm or less. When the depth of the center of the cavity portion is within the above range, the optical surface portion of the obtained molded sheet can be advantageously used as a transmissive optical element such as a lens.
　更に、金型は、閉型状態における成形シート形成面間の最小間隔（Ｈｍｉｎ）が、５０μｍ以上であることが好ましく、１００μｍ以上であることがより好ましく、５００μｍ以下であることが好ましく、３００μｍ以下であることがより好ましく、２００μｍ以下であることが更に好ましい。最小間隔が上記上限値以下であれば、得られる成形シートの光学面状部の厚み精度のバラツキを小さくすることができると共に、形状精度を高めることができる。また、最小間隔が上記下限値以上であれば、得られる成形シートの強度を十分に確保することができる。 Further, in the mold, the minimum distance (H min ) between the formed sheet forming surfaces in the closed state is preferably 50 μm or more, more preferably 100 μm or more, preferably 500 μm or less, and preferably 300 μm. It is more preferably less than or equal to, and even more preferably 200 μm or less. When the minimum interval is not more than the above upper limit value, the variation in the thickness accuracy of the optical surface-shaped portion of the obtained molded sheet can be reduced, and the shape accuracy can be improved. Further, when the minimum interval is not more than the above lower limit value, the strength of the obtained molded sheet can be sufficiently secured.
［プレス温度］
　熱プレス工程において一対の金型で熱可塑性樹脂フィルムを熱プレスする際のプレス温度（金型温度）は、熱可塑性樹脂のガラス転移温度（Ｔｇ）よりも４０℃高い温度（Ｔｇ＋４０℃）以上であることが好ましく、プレス温度は、ガラス転移温度よりも５０℃高い温度（Ｔｇ＋５０℃）以上であることがより好ましく、ガラス転移温度よりも５５℃高い温度（Ｔｇ＋５５℃）以上であることがさらに好ましい。プレス温度が上記下限値以上であれば、得られる成形シートの光学面状部の厚み精度のバラツキを小さくすることができると共に、形状精度を高めることができる。なお、効率的に成形シートを製造する観点からは、プレス温度は、ガラス転移温度よりも８０℃高い温度（Ｔｇ＋８０℃）以下とすることが好ましい。
　なお、プレス温度は、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）に従って金型の温度を制御することにより、適宜調節することができる。 [Press temperature]
The press temperature (mold temperature) when the thermoplastic resin film is hot-pressed with a pair of molds in the hot pressing process is 40 ° C. higher (Tg + 40 ° C.) or higher than the glass transition temperature (Tg) of the thermoplastic resin. The press temperature is more preferably 50 ° C. higher than the glass transition temperature (Tg + 50 ° C.), and further preferably 55 ° C. higher than the glass transition temperature (Tg + 55 ° C.). .. When the press temperature is at least the above lower limit value, the variation in the thickness accuracy of the optical surface-shaped portion of the obtained molded sheet can be reduced, and the shape accuracy can be improved. From the viewpoint of efficiently producing the molded sheet, the press temperature is preferably set to a temperature (Tg + 80 ° C.) or less that is 80 ° C. higher than the glass transition temperature.
The press temperature is not particularly limited, and is appropriately adjusted by controlling the temperature of the die according to a known general method (for example, a temperature control method using a known heater and cooler). Can be done.
［プレス圧力］
　熱プレス工程では、金型で熱可塑性樹脂フィルムを熱プレスする際のプレス圧力を、所定の昇圧速度で最終プレス圧力まで昇圧させた後、任意に最終プレス圧力で所定時間保持することが好ましい。 [Press pressure]
In the hot pressing step, it is preferable that the press pressure at the time of hot pressing the thermoplastic resin film with the die is increased to the final press pressure at a predetermined pressurizing rate, and then arbitrarily held at the final press pressure for a predetermined time.
－昇圧速度－
　ここで、プレス圧力の平均昇圧速度は、０．１ＭＰａ／秒以下であることが好ましく、０．０７ＭＰａ／秒以下であることがより好ましく、０．０５ＭＰａ／秒以下であることがさらに好ましい。平均昇圧速度が上記上限値以下であれば、得られる成形シートの光学面状部の複屈折を小さくすることができると共に、形状精度を高めることができる。なお、効率的に成形シートを製造する観点からは、平均昇圧速度は、０．０４ＭＰａ／秒以上とすることが好ましい。 -Boosting speed-
Here, the average pressurizing rate of the press pressure is preferably 0.1 MPa / sec or less, more preferably 0.07 MPa / sec or less, and further preferably 0.05 MPa / sec or less. When the average step-up speed is not more than the above upper limit value, the birefringence of the optical surface portion of the obtained molded sheet can be reduced and the shape accuracy can be improved. From the viewpoint of efficiently producing the molded sheet, the average step-up rate is preferably 0.04 MPa / sec or more.
－最終プレス圧力－
　最終プレス圧力は、特に限定されることなく、例えば１ＭＰａ以上１０ＭＰａ以下とすることができる。最終プレス圧力が上記範囲内であれば、得られる成形シートの光学面状部の形状精度を更に高めると共に、厚み精度のバラツキ及び複屈折を更に小さくすることができる。 -Final press pressure-
The final press pressure is not particularly limited and can be, for example, 1 MPa or more and 10 MPa or less. When the final press pressure is within the above range, the shape accuracy of the optical surface of the obtained molded sheet can be further improved, and the variation in thickness accuracy and birefringence can be further reduced.
［その他のプレス条件］
　なお、熱プレス工程における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、目的とする成形シート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、最終プレス圧力までプレス圧力を昇圧させる時間は、２０秒以上３００秒以下とすることができ、プレス圧力を最終プレス圧力で保持する時間は、０秒以上１８０秒以下とすることができる。 [Other press conditions]
The pressing time in the heat pressing step is not particularly limited, and can be appropriately determined according to the type and size of the thermoplastic resin film to be used, the shape and size of the target molded sheet, and the like. For example, the time for increasing the press pressure to the final press pressure can be 20 seconds or more and 300 seconds or less, and the time for holding the press pressure at the final press pressure can be 0 seconds or more and 180 seconds or less.
＜離型工程＞
　離型工程では、熱プレス工程にて得た成形シートを一対の金型から離型する際に、一対の金型を（Ｔｇ－８０）℃以上（Ｔｇ－１５）℃以下の温度（以下、「離型温度」とも称することがある。）にて離型する。かかる工程を実施することで、得られる成形シートに含まれる複数の光学面状部の形状精度を一層高め、厚み精度のバラツキを一層小さくし、さらには、複屈折を一層小さくすることができる。なお、離型工程の始点は、例えば、熱プレス工程の開始時点から所定時間経過後に、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、金型に対する熱入力を停止した時点であり得る。 <Release process>
In the mold release step, when the molding sheet obtained in the heat pressing step is released from the pair of dies, the temperature of the pair of dies is (Tg-80) ° C. or higher (Tg-15) ° C. or lower (hereinafter, The mold is released at (sometimes referred to as "release temperature"). By carrying out such a step, it is possible to further improve the shape accuracy of the plurality of optical surface-shaped portions contained in the obtained molded sheet, further reduce the variation in thickness accuracy, and further reduce the birefringence. The starting point of the mold release process is, for example, a time when a predetermined time elapses from the start time of the heat pressing process, a time when temperature control for cooling the die is started, or a time after a predetermined time elapses from the start time of the heat pressing process. , It may be the time when the heat input to the mold is stopped.
［離型温度］
　離型温度は、熱可塑性樹脂のガラス転移温度（Ｔｇ）以下である必要があり、ガラス転移温度よりも１５℃低い温度（Ｔｇ－１５℃）以下が好ましく、ガラス転移温度よりも２０℃低い温度（Ｔｇ－２０℃）以下がより好ましく、ガラス転移温度よりも３０℃低い温度（Ｔｇ－３０℃）以下がさらに好ましい。また、離型温度は、ガラス転移温度よりも８０℃低い温度（Ｔｇ－８０℃）以上であることが好ましく、ガラス転移温度よりも７５℃低い温度（Ｔｇ－７５℃）以上であることがより好ましい。離型温度が上記上限値以下であれば、離型し易く、得られる成形シートの光学面状部の形状精度を効果的に高めることができる。さらに、離型温度が上記上限値以下であれば、得られる成形シートの光学面状部厚み精度のバラツキを小さくし、且つ、複屈折を小さくすることができる。さらにまた、離型温度が上記上限値以下であれば、離型時におけるトラブルの発生を抑制して、成形シートの製造効率を一層高めることができる。また、離型温度が上記下限値以上であれば、一対の金型の冷却、及び後続する熱プレス工程における昇温の際に要する温度調整時間を短縮することができ、成形シートの製造効率を一層高めることができる。 [Release temperature]
The mold release temperature needs to be equal to or lower than the glass transition temperature (Tg) of the thermoplastic resin, preferably 15 ° C. lower than the glass transition temperature (Tg-15 ° C.), and 20 ° C. lower than the glass transition temperature. It is more preferably (Tg-20 ° C.) or lower, and further preferably 30 ° C. lower than the glass transition temperature (Tg-30 ° C.) or lower. The mold release temperature is preferably 80 ° C. lower than the glass transition temperature (Tg-80 ° C.) or higher, and 75 ° C. lower than the glass transition temperature (Tg-75 ° C.) or higher. preferable. When the mold release temperature is not more than the above upper limit value, it is easy to release the mold, and the shape accuracy of the optical surface-shaped portion of the obtained molded sheet can be effectively improved. Further, when the mold release temperature is not more than the above upper limit value, the variation in the thickness accuracy of the optical surface portion of the obtained molded sheet can be reduced, and the birefringence can be reduced. Furthermore, when the mold release temperature is not more than the above upper limit value, it is possible to suppress the occurrence of troubles at the time of mold release and further improve the production efficiency of the molded sheet. Further, when the mold release temperature is equal to or higher than the above lower limit value, the temperature adjustment time required for cooling the pair of dies and raising the temperature in the subsequent heat pressing step can be shortened, and the manufacturing efficiency of the molded sheet can be improved. It can be further enhanced.
［その他の離型条件］
　離型温度まで金型を冷却するための所要時間（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、枚葉状のシート材料の種類及びサイズ、目的とする成形シートの光学面状部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 release conditions]
The time required to cool the mold to the mold release temperature (mold cooling time), the mold cooling rate, etc. are not particularly limited, and the type and size of the sheet-fed sheet material, the target molded sheet, and the like are not particularly limited. It can be appropriately determined according to the shape and size of the optical surface portion. 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.
　そして、離型工程では、離型温度まで金型を冷却した後に、熱プレスフィルムを金型から離型して、成形シートを得る。 Then, in the mold release process, after the mold is cooled to the mold release temperature, the hot press film is released from the mold to obtain a molded sheet.
（光学素子の製造方法）
　本発明の光学素子の製造方法は、本発明の製造方法に従って得られた成形シートを、複数の光学面状部のそれぞれに対応する位置で分離して、複数の光学素子を得る、光学素子分離工程を含むことを特徴とする。かかる本発明の製造方法によれば、形状精度が十分に高く、厚み精度のバラツキが小さく、且つ、複屈折が十分に小さい光学素子を、容易に製造することができる。 (Manufacturing method of optical element)
The method for manufacturing an optical element of the present invention is to separate a molded sheet obtained according to the manufacturing method of the present invention at a position corresponding to each of a plurality of optical planar portions to obtain a plurality of optical elements. It is characterized by including a process. According to the manufacturing method of the present invention, it is possible to easily manufacture an optical element having sufficiently high shape accuracy, small variation in thickness accuracy, and sufficiently small birefringence.
＜光学素子分離工程＞
　光学素子分離工程では、本発明の製造方法に従って得られた成形シートから、複数の光学素子を分離する。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、レーザーカット等の既知のあらゆる方法で、成形シートから、一つ一つの光学素子を分離することができる。 <Optical element separation process>
In the optical element separation step, a plurality of optical elements are separated from the molded sheet obtained according to the manufacturing method of the present invention. The separation method is not particularly limited, and each optical element can be separated from the molded sheet by any known method such as punching with a punching die or laser cutting.
　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、熱可塑性樹脂の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、成形シートの光学面状部の形状精度、厚み精度のバラツキ及び位相差、並びに、成形シートの生産性は、以下のようにして評価した。実施例及び比較例における配置～離型までの各種操作は、全て常圧にて、即ち、金型内部を加圧又は減圧雰囲気としない条件にて実施した。 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 glass transition temperature of the thermoplastic resin was measured as follows. Further, in Examples and Comparative Examples, the shape accuracy, the variation in thickness accuracy and the phase difference of the optical surface portion of the molded sheet, and the productivity of the molded sheet were evaluated as follows. Various operations from placement to mold release in Examples and Comparative Examples were all carried out under normal pressure, that is, under conditions where the inside of the mold was not pressurized or depressurized.
＜熱可塑性樹脂のガラス転移温度＞
　熱可塑性樹脂のガラス転移温度（Ｔｇ）は、示差走査熱量分析計（日立ハイテクサイエンス社製、「ＤＳＣ６２２０」）を用いて、ＪＩＳ Ｋ７１２１：２０１２に基づき昇温速度１０℃／分の条件で測定した。 <Glass transition temperature of thermoplastic resin>
The glass transition temperature (Tg) of the thermoplastic resin was measured using a differential scanning calorimeter (“DSC6220” manufactured by Hitachi High-Tech Science Co., Ltd.) under the condition of a heating rate of 10 ° C./min based on JIS K7121: 2012. ..
＜形状精度＞
　成形シートの光学面状部を打ち抜き、光学レンズを得て測定試料とした。なお、実施例、比較例に従って得た光学レンズは、表面及び裏面が、それぞれ、光学レンズの厚み方向に沿う断面形状が変曲点を有する非球面形状を有する、非球面レンズであった。
　次に、打ち抜いた光学面状部のうち３００個の測定試料について、形状測定器（パナソニック社製、「ＵＡ－３Ｐ」）を用いて、光学面の設計値を基準とするＰＶ値（基準表面に対する測定試料の表面の形状の最大誤差、即ち測定範囲内での最も高い点（Ｐｅａｋ）と最も低い点（Ｖａｌｌｅｙ）の差）を測定した。そして、測定したＰＶ値の単純平均値を形状精度として以下の基準で評価した。
　Ａ：ＰＶ値の単純平均値が０．５μｍ以下
　Ｂ：ＰＶ値の単純平均値が０．５μｍ超１．０μｍ以下
　Ｃ：ＰＶ値の単純平均値が１．０μｍ超２．０μｍ以下
　Ｄ：ＰＶ値の単純平均値が２．０μｍ超
＜厚み精度のバラツキ＞
　成形シートの光学面状部を打ち抜き、光学レンズを得て測定試料とした。
　次に、得られた光学レンズのうち３００個の測定試料について、中心の厚みを、形状測定器（パナソニック社製、「ＵＡ－３Ｐ」）を用いて測定した。そして、測定した厚みの標準偏差を厚み精度のバラツキとして以下の基準で評価した。
　Ａ：標準偏差が０．１μｍ以下
　Ｂ：標準偏差が０．１μｍ超０．２μｍ以下
　Ｃ：標準偏差が０．２μｍ超
＜位相差＞
　成形シートの光学面状部を打ち抜き、光学レンズを得て測定試料とした。
　次に、得られた光学レンズのうち３００個の測定試料について、樹脂成形レンズ検査システム（フォトニックスラティス社製、「ＷＰＡ－１００」）を用いて位相差を測定した。
　測定波長（５４３ｎｍ）で規格化した値として得られる位相差の値の単純平均値を用いて、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：位相差の単純平均値が２０ｎｍ以下
　Ｂ：位相差の単純平均値が２０ｎｍ超５０ｎｍ以下
　Ｃ：位相差の単純平均値が５０ｎｍ超 <Shape accuracy>
The optical surface of the molded sheet was punched out to obtain an optical lens, which was used as a measurement sample. The optical lenses obtained according to Examples and Comparative Examples were aspherical lenses having an aspherical shape having an inflection point in the cross-sectional shape along the thickness direction of the optical lens, respectively, on the front surface and the back surface.
Next, for 300 measurement samples out of the punched optical surface-like parts, a shape measuring instrument (manufactured by Panasonic, "UA-3P") was used to obtain PV values (reference surface) based on the design value of the optical surface. The maximum error of the surface shape of the measurement sample, that is, the difference between the highest point (Peek) and the lowest point (Valley) within the measurement range) was measured. Then, the simple average value of the measured PV values was evaluated as the shape accuracy according to the following criteria.
A: Simple average value of PV value is 0.5 μm or less B: Simple average value of PV value is more than 0.5 μm and 1.0 μm or less C: Simple average value of PV value is more than 1.0 μm and 2.0 μm or less D: PV Simple average value exceeds 2.0 μm <Variation in thickness accuracy>
The optical surface of the molded sheet was punched out to obtain an optical lens, which was used as a measurement sample.
Next, the thickness of the center of 300 measurement samples of the obtained optical lenses was measured using a shape measuring device (“UA-3P” manufactured by Panasonic Corporation). Then, the standard deviation of the measured thickness was evaluated as a variation in thickness accuracy according to the following criteria.
A: Standard deviation is 0.1 μm or less B: Standard deviation is more than 0.1 μm and 0.2 μm or less C: Standard deviation is more than 0.2 μm <Phase difference>
The optical surface of the molded sheet was punched out to obtain an optical lens, which was used as a measurement sample.
Next, the phase difference of 300 measurement samples of the obtained optical lenses was measured using a resin molded lens inspection system (“WPA-100” manufactured by Photonics Lattice Co., Ltd.).
The evaluation was made according to the following criteria using the simple average value of the phase difference values obtained as the values standardized at the measurement wavelength (543 nm). The smaller the phase difference value, the smaller the birefringence.
A: Simple average value of phase difference is 20 nm or less B: Simple average value of phase difference is more than 20 nm and 50 nm or less C: Simple average value of phase difference is more than 50 nm
＜連続生産性＞
　枚葉状のシート材料１００枚を成形シートへ加工した際に起こったトラブルによる装置の停止時間の合計を、以下の基準に従って評価した。
　Ａ：停止時間３０分未満
　Ｂ：停止時間３０分以上１２０分未満
　Ｃ：停止時間１２０分以上 <Continuous productivity>
The total downtime of the apparatus due to troubles that occurred when 100 sheet-fed sheet materials were processed into molded sheets was evaluated according to the following criteria.
A: Stop time less than 30 minutes B: Stop time 30 minutes or more and less than 120 minutes C: Stop time 120 minutes or more
（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、厚みが５００μｍである、幅２９５ｍｍの熱可塑性樹脂フィルムを１００ｍ以上の長さで得た。このようにして得られた熱可塑性樹脂フィルムを２５０ｍｍ角に切り出して枚葉状のシート材料として使用した。
　上記に従って得られた枚葉状のシート材料を、温度調節装置を有する、一対の３００ｍｍ角の金型を備える熱プレス成形機にセットした（配置操作）。なお、一対の金型としては、表１に示す性状を有するものを用いた。
　そして、金型の温度を表１に示すプレス温度まで昇温させた後、表１に示す条件で枚葉状のシート材料を昇圧速度０．０４５ＭＰａ／秒で９．５ＭＰａまで昇圧させつつ熱プレスした（熱プレス工程）。
　さらに、枚葉状のシート材料をプレスしたままの状態で、一対の金型を１００℃まで冷却して、金型間に挟まれた状態の成形シートを冷却した。その後、一対の金型を開いて表１に示す性状の成形シートを一対の金型から剥離した（離型工程）。なお、成形シートにおける光学面状部の直径は金型におけるキャビティ部の直径Ｄに対応し、光学面状部間の最小間隔は金型におけるキャビティ部の最小間隔Ｐに対応し、光学面状部の配設密度は金型におけるキャビティ部の配設密度に対応し、光学面状部の中心の厚みは閉型状態におけるキャビティ部の中心の深さＨｍｉｄに対応し、成形シートの最薄部の厚みは、閉型状態における成形シート形成面間の最小間隔Ｈｍｉｎが対応する。
　得られた成形シートについて、上記に従って各種評価を行った結果を、シート材料の配置から成形シートの離型までの時間（サイクルタイム）と共に表１に示す。 (Example 1)
A thermoplastic resin containing a norbornene-based ring-opening polymer hydride (ZEONEX E48R (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). ), This was melted at 260 ° C., the molten resin was extruded from the T-die, and this was cooled to obtain a thermoplastic resin film having a thickness of 500 μm and a width of 295 mm and a length of 100 m or more. The thermoplastic resin film thus obtained was cut into 250 mm squares and used as a single-wafer-shaped sheet material.
The sheet-fed sheet material obtained according to the above was set in a heat press molding machine equipped with a pair of 300 mm square dies having a temperature control device (arrangement operation). As the pair of molds, those having the properties shown in Table 1 were used.
Then, after raising the temperature of the die to the press temperature shown in Table 1, the sheet-fed sheet material was hot-pressed under the conditions shown in Table 1 while increasing the pressure to 9.5 MPa at a step-up rate of 0.045 MPa / sec. (Hot press process).
Further, while the single-wafer-shaped sheet material was still pressed, the pair of dies were cooled to 100 ° C. to cool the molded sheet sandwiched between the dies. Then, the pair of dies were opened and the molded sheet having the properties shown in Table 1 was peeled off from the pair of dies (mold release step). The diameter of the optical surface portion of the molded sheet corresponds to the diameter D of the cavity portion in the mold, and the minimum distance between the optical surface portions corresponds to the minimum distance P of the cavity portion in the mold. The arrangement density of the cavity corresponds to the arrangement density of the cavity in the mold, the thickness of the center of the optical surface corresponds to the depth H mid of the center of the cavity in the closed state, and the thinnest part of the molded sheet. Corresponds to the minimum distance H min between the molded sheet forming surfaces in the closed state.
The results of various evaluations of the obtained molded sheet according to the above are shown in Table 1 together with the time (cycle time) from the arrangement of the sheet material to the release of the molded sheet.
（実施例２～４）
　一対の金型を表１に示す性状の金型に変更したこと以外は実施例１と同様にして成形シートを製造し、各種評価を行った。結果を表１に示す。 (Examples 2 to 4)
A molded sheet was produced in the same manner as in Example 1 except that the pair of dies were changed to the dies having the properties shown in Table 1, and various evaluations were performed. The results are shown in Table 1.
（実施例５～７）
　離型工程における離型温度を、表１に示す温度に変更したこと以外は実施例１と同様にして成形シートを製造し、各種評価を行った。結果を表１に示す。 (Examples 5 to 7)
A molded sheet was produced in the same manner as in Example 1 except that the mold release temperature in the mold release step was changed to the temperature shown in Table 1, and various evaluations were performed. The results are shown in Table 1.
（実施例８）
　４００ｍｍ角に切り出したシート材料を用いたこと以外は実施例１と同様にして成形シートを製造し、各種評価を行った。結果を表１に示す。本実施例に従う熱プレス工程では、枚葉状のシート材料の端部が、一対の金型からはみ出していた。 (Example 8)
A molded sheet was produced in the same manner as in Example 1 except that a sheet material cut into a 400 mm square was used, and various evaluations were performed. The results are shown in Table 1. In the heat pressing process according to this embodiment, the edges of the sheet-fed sheet material protruded from the pair of dies.
（実施例９）
　熱可塑性樹脂フィルムとして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℃）を用い、プレス温度を表１に示す温度に変更したこと以外は実施例１と同様にして成形シートを製造し、各種評価を行った。結果を表１に示す。 (Example 9)
As the thermoplastic resin film, a thermoplastic resin containing a norbornene-ethylene random copolymer obtained by random addition polymerization using norbornene and ethylene as monomers (TOPAS6013 (manufactured by Polyplastics), glass transition temperature: 138 ° C.) was used. A molded sheet was produced in the same manner as in Example 1 except that the press temperature was changed to the temperature shown in Table 1, and various evaluations were performed. The results are shown in Table 1.
（実施例１０）
　熱可塑性樹脂フィルムとして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℃）を用い、プレス温度を表１に示す温度に変更したこと以外は実施例１と同様にして成形シートを製造し、各種評価を行った。結果を表１に示す。 (Example 10)
Polycarbonate resin (Wonderlight PC-115 (manufactured by Asahi Kasei Co., Ltd.), glass transition temperature: 145 ° C.) was used as the thermoplastic resin film, and the press temperature was changed to the temperature shown in Table 1 in the same manner as in Example 1. A molded sheet was manufactured and various evaluations were performed. The results are shown in Table 1.
（実施例１１）
　熱可塑性樹脂フィルムとして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℃）を用い、プレス温度を表１に示す温度に変更したこと以外は実施例１と同様にして成形シートを製造し、各種評価を行った。結果を表１に示す。 (Example 11)
Polymethylmethacrylate resin (Delpet 80NH (manufactured by Asahi Kasei Chemicals Co., Ltd.), glass transition temperature: 100 ° C.) was used as the thermoplastic resin film, and the same as in Example 1 except that the press temperature was changed to the temperature shown in Table 1. The molded sheet was manufactured and various evaluations were performed. The results are shown in Table 1.
（実施例１２）
　熱可塑性樹脂フィルムとしてポリエステル樹脂（ＯＫＰ－１（大阪ガスケミカル社製）、ガラス転移温度：１３２℃）を用い、プレス温度を表１に示す温度に変更したこと以外は実施例１と同様にして成形シートを製造し、各種評価を行った。結果を表１に示す。 (Example 12)
A polyester resin (OKP-1 (manufactured by Osaka Gas Chemical Co., Ltd.), glass transition temperature: 132 ° C.) was used as the thermoplastic resin film, and the press temperature was changed to the temperature shown in Table 1 in the same manner as in Example 1. A molded sheet was manufactured and various evaluations were performed. The results are shown in Table 1.
（比較例１）
　一対の金型を、表１に示す性状の金型に変更したこと以外は実施例１と同様にして成形シートを製造し、各種評価を行った。結果を表１に示す。 (Comparative Example 1)
A molded sheet was produced in the same manner as in Example 1 except that the pair of dies were changed to the dies having the properties shown in Table 1, and various evaluations were performed. The results are shown in Table 1.
（比較例２）
　一対の３００ｍｍ角の金型を備える熱プレス成形機を、金型間の間隔を２０ｍｍに設定した四対の１００ｍｍ角の金型を２×２の配置態様で備える熱プレス成形機に変更した。かかる熱プレス成型機を用いて、枚葉状のシート材料を４対の金型で同時成形したこと以外は実施例１と同様にして成形シートの製造を試みたが、成形時にシート材料が金型間の間隙にて破れてしまい、成形シートを製造できなかった。 (Comparative Example 2)
The hot press molding machine equipped with a pair of 300 mm square dies was changed to a hot press molding machine equipped with four pairs of 100 mm square dies in a 2 × 2 arrangement mode in which the distance between the dies was set to 20 mm. An attempt was made to manufacture a molded sheet in the same manner as in Example 1 except that the sheet-fed sheet material was simultaneously molded with four pairs of dies using such a hot press molding machine, but the sheet material was a die at the time of molding. The molded sheet could not be manufactured because it was torn in the gap between them.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１より、実施例１～１２の成形シートは形状精度が十分に高く、厚み精度のバラツキが小さく、且つ、複屈折が十分に小さい、複数の光学面状部を有することが分かる。さらに、実施例１～１２の成形シートは連続生産性に優れていたことが分かる。また、比較例１の成形シートは、光学面状部の形状精度が低く、厚み精度のバラツキが大きく、且つ、複屈折が大きかったことが分かる。また、比較例１の成形シートは連続生産性に乏しかったことが分かる。 From Table 1, it can be seen that the molded sheets of Examples 1 to 12 have a plurality of optical planar portions having sufficiently high shape accuracy, small variation in thickness accuracy, and sufficiently small birefringence. Further, it can be seen that the molded sheets of Examples 1 to 12 were excellent in continuous productivity. Further, it can be seen that the molded sheet of Comparative Example 1 had low shape accuracy of the optical surface-like portion, large variation in thickness accuracy, and large birefringence. Further, it can be seen that the molded sheet of Comparative Example 1 was poor in continuous productivity.
　本発明によれば、形状精度が十分に高く、厚み精度のバラツキが小さく、且つ、低複屈折性の、複数の光学面状部を有する成形シートを提供することができる。
　また、本発明によれば、上記成形シートを効率的に製造することができる成形シートの製造方法を提供することができる。
　さらに、本発明によれば、上記成形シートを用いた光学素子の製造方法を提供することができる。 According to the present invention, it is possible to provide a molded sheet having a plurality of optical planar portions, which has sufficiently high shape accuracy, small variation in thickness accuracy, and low birefringence.
Further, according to the present invention, it is possible to provide a method for producing a molded sheet capable of efficiently producing the molded sheet.
Further, according to the present invention, it is possible to provide a method for manufacturing an optical element using the above-mentioned molded sheet.
１　　　一対の金型
１Ａ　　上側金型
１Ｂ　　下側金型
１０　　成形シート
１０’　枚葉状のシート材料
１１　　光学面状部 1 Pair of molds 1A Upper mold 1B Lower mold 10 Molded sheet 10'Sheet sheet material 11 Optical surface

Claims (7)

  1. 　熱可塑性樹脂を用いて形成された熱可塑性樹脂フィルムを熱プレス成型して、複数の光学面状部を有する成形シートを製造する、成形シートの製造方法であって、
    　前記熱可塑性樹脂フィルムよりなる枚葉状のシート材料を、互いに離隔した複数の光学面形成領域を有する一対の金型を用いて常圧下で熱プレス成形して成形シートを得る熱プレス工程を含む、
    成形シートの製造方法。     A method for producing a molded sheet, which comprises hot-press molding a thermoplastic resin film formed using a thermoplastic resin to produce a molded sheet having a plurality of optical planar portions.
    A heat-pressing step of obtaining a molded sheet by hot-press molding a sheet-fed sheet material made of the thermoplastic resin film under normal pressure using a pair of dies having a plurality of optical surface forming regions separated from each other is included.
    Manufacturing method of molded sheet.
  2. 　前記熱可塑性樹脂のガラス転移温度をＴｇ（℃）として、
    　前記熱プレス工程にて得た前記成形シートを前記一対の金型から離型する際に、前記一対の金型を（Ｔｇ－８０）℃以上（Ｔｇ－１５）℃以下の温度にて離型する、離型工程を含む、
    請求項１に記載の成形シートの製造方法。     Let Tg (° C.) be the glass transition temperature of the thermoplastic resin.
    When the molded sheet obtained in the heat pressing step is released from the pair of dies, the pair of dies are released at a temperature of (Tg-80) ° C. or higher and (Tg-15) ° C. or lower. , Including mold release process,
    The method for manufacturing a molded sheet according to claim 1.
  3. 　前記熱プレス工程にて、前記一対の金型により前記枚葉状のシート材料をプレスした状態で、前記枚葉状のシート材料が、前記一対の金型からはみ出さない、請求項１又は２に記載の成形シートの製造方法。 The first or second aspect of the present invention, wherein the single-wafer-shaped sheet material does not protrude from the pair of dies in a state where the single-wafer-shaped sheet material is pressed by the pair of dies in the hot pressing step. How to manufacture molded sheets.
  4. 　前記熱可塑性樹脂が脂環式構造含有樹脂である、請求項１～３の何れかに記載の成形シートの製造方法。 The method for producing a molded sheet according to any one of claims 1 to 3, wherein the thermoplastic resin is an alicyclic structure-containing resin.
  5. 　請求項１～４の何れかに記載の成形シートの製造方法に従って得られた前記成形シートを、前記複数の光学面状部のそれぞれに対応する位置で分離して、複数の光学素子を得る、光学素子分離工程を含む、光学素子の製造方法。 The molded sheet obtained according to the method for producing a molded sheet according to any one of claims 1 to 4 is separated at a position corresponding to each of the plurality of optical planar portions to obtain a plurality of optical elements. A method for manufacturing an optical element, which includes an optical element separation step.
  6. 　熱可塑性樹脂を用いて形成された、光学面状部を複数有する、枚葉状の成形シートであって、
    　前記光学面状部の配設密度が０．１６個／ｃｍ２以上であり、
    　互いに隣接する前記光学面状部間の最小間隔が１．０ｍｍ以上であり、
    　平面視における前記光学面状部の直径が１ｍｍ以上１５ｍｍ以下であり、
    　前記光学面状部の位相差が５０ｎｍ以下であり、
    　前記光学面状部の厚み精度のバラツキが０．２μｍ以下である、成形シート。     A single-wafer-shaped molded sheet having a plurality of optical surface-like portions formed by using a thermoplastic resin.
    The arrangement density of the optical surface-like portion is 0.16 pieces / cm 2 or more.
    The minimum distance between the optical surface portions adjacent to each other is 1.0 mm or more, and the distance is 1.0 mm or more.
    The diameter of the optical planar portion in a plan view is 1 mm or more and 15 mm or less.
    The phase difference of the optical surface portion is 50 nm or less, and the optical surface-like portion has a phase difference of 50 nm or less.
    A molded sheet having a variation in thickness accuracy of the optical surface portion of 0.2 μm or less.
  7. 　前記光学面状部の少なくとも一方の表面は、厚み方向の断面形状が変曲点を有する非球面形状である、請求項６に記載の成形シート。 The molded sheet according to claim 6, wherein at least one surface of the optical planar portion has an aspherical shape having an inflection point in the cross-sectional shape in the thickness direction.
PCT/JP2021/002480 2020-01-29 2021-01-25 Molded sheet, method for manufacturing molded sheet, and method for manufacturing optical element WO2021153512A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
KR1020227023478A KR20220133188A (en) 2020-01-29 2021-01-25 A molding sheet and a method for manufacturing a molding sheet, and a method for manufacturing an optical element
JP2021574028A JPWO2021153512A1 (en) 2020-01-29 2021-01-25
CN202180006956.0A CN114786903A (en) 2020-01-29 2021-01-25 Molding sheet, method for producing molding sheet, and method for producing optical element

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2020012936 2020-01-29
JP2020-012936 2020-01-29

Publications (1)

Publication Number Publication Date
WO2021153512A1 true WO2021153512A1 (en) 2021-08-05

Family

ID=77078265

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2021/002480 WO2021153512A1 (en) 2020-01-29 2021-01-25 Molded sheet, method for manufacturing molded sheet, and method for manufacturing optical element

Country Status (5)

Country Link
JP (1) JPWO2021153512A1 (en)
KR (1) KR20220133188A (en)
CN (1) CN114786903A (en)
TW (1) TW202138159A (en)
WO (1) WO2021153512A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09267404A (en) * 1996-01-31 1997-10-14 Matsushita Electric Ind Co Ltd Optical element by pressure molding, its production and press mold
WO2017126599A1 (en) * 2016-01-22 2017-07-27 日本ゼオン株式会社 Method for producing optical lens

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000012291A1 (en) 1998-08-28 2000-03-09 Specialty Ultravision, Inc. Method and device for producing lens
TW446823B (en) * 1999-03-31 2001-07-21 Rohm Co Ltd Lens array unit, method for producing lens array, and optical device using said lens array unit
ATE410289T1 (en) * 2001-08-10 2008-10-15 Sekisui Chemical Co Ltd OPTICAL PLASTIC FILM, METHOD FOR THE PRODUCTION THEREOF AND POLARIZER
TW578016B (en) * 2001-08-10 2004-03-01 Sekisui Chemical Co Ltd Optical film, its process and polarizing sheet
JP2008044136A (en) * 2006-08-11 2008-02-28 Kuraray Co Ltd Optical sheet manufacturing method and display screen manufacturing method
JP4135768B2 (en) * 2006-09-27 2008-08-20 東レ株式会社 Intermittent film forming apparatus and method
JPWO2009044673A1 (en) * 2007-10-05 2011-02-03 コニカミノルタオプト株式会社 Optical film, method for producing the same, polarizing plate, and display device
KR20100032767A (en) * 2008-09-18 2010-03-26 제일모직주식회사 Diffusing film having micro lens pattern and embossed pattern
JP2010264652A (en) * 2009-05-14 2010-11-25 Fujifilm Corp Method and apparatus for manufacturing shaped article
JP2013039827A (en) * 2011-07-19 2013-02-28 Sumitomo Chemical Co Ltd Optical sheet manufacturing method
JP6478145B2 (en) * 2014-11-14 2019-03-06 大日本印刷株式会社 Imprint mold, imprint method, method for manufacturing wire grid polarizer, and wire grid polarizer
EP3281925A4 (en) * 2015-04-10 2019-05-01 Sekisui Chemical Co., Ltd. Interlayer for laminated glass, laminated glass, production method for embossing roll, and production method for interlayer for laminated glass

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09267404A (en) * 1996-01-31 1997-10-14 Matsushita Electric Ind Co Ltd Optical element by pressure molding, its production and press mold
WO2017126599A1 (en) * 2016-01-22 2017-07-27 日本ゼオン株式会社 Method for producing optical lens

Also Published As

Publication number Publication date
TW202138159A (en) 2021-10-16
CN114786903A (en) 2022-07-22
JPWO2021153512A1 (en) 2021-08-05
KR20220133188A (en) 2022-10-04

Similar Documents

Publication Publication Date Title
KR20070026264A (en) A method for producing the optical film
CN100532070C (en) Device and method for manufacturing panel with embossing on surface
JP6844550B2 (en) Manufacturing method of optical lens
WO2021153512A1 (en) Molded sheet, method for manufacturing molded sheet, and method for manufacturing optical element
KR20030059200A (en) Method for producing embossed sheet and embossed sheet
WO2021065489A1 (en) Resin sheet and resin-sheet manufacturing method
WO2021006126A1 (en) Transmissive optical element manufacturing method
KR20130117353A (en) Nano-layered light guide plate
KR20130117727A (en) Method of manufacturing a nano-layered light guide plate
JP2014072192A (en) Composite light guide plate
JP7225799B2 (en) Manufacturing method of transmissive optical element
JP7259366B2 (en) Heat press device and method for manufacturing compact
JP2021151780A (en) Method for manufacturing optical component
JP2021098206A (en) Method for manufacturing transmission type optical element
JP2011088348A (en) Resin sheet molding, method of manufacturing the same, and hot pressing mold
JP6229482B2 (en) Optical lens molding method
JP2016147502A (en) Mold for molding optical lens and method for producing optical lens
JP2001239556A (en) Method for molding thermoplastic resin
JP2008032893A (en) Method of manufacturing prism sheet, prism sheet and optical sheet
JP2011005820A (en) Molding method of optical element, and optical element
JP2011189617A (en) Composite resin mold for curable composition
JP2011194583A (en) Method for manufacturing prism film
JP2007253379A (en) Method for producing tabular molding
JP2004050819A (en) Molding method of molded body, and molded body
JP2001038773A (en) Method for molding molded article for optical part

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21747628

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2021574028

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21747628

Country of ref document: EP

Kind code of ref document: A1