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WO2025182448A1 - Film stratifié, procédé de production de film stratifié, élément optique et procédé de production d'élément optique - Google Patents

Film stratifié, procédé de production de film stratifié, élément optique et procédé de production d'élément optique

Info

Publication number
WO2025182448A1
WO2025182448A1 PCT/JP2025/003228 JP2025003228W WO2025182448A1 WO 2025182448 A1 WO2025182448 A1 WO 2025182448A1 JP 2025003228 W JP2025003228 W JP 2025003228W WO 2025182448 A1 WO2025182448 A1 WO 2025182448A1
Authority
WO
WIPO (PCT)
Prior art keywords
refractive index
low refractive
index portion
film
substrate
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
PCT/JP2025/003228
Other languages
English (en)
Japanese (ja)
Inventor
太一 渡邉
太幹 岩崎
高明 谷上
大介 尾込
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nitto Denko Corp
Original Assignee
Nitto Denko Corp
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 Nitto Denko Corp filed Critical Nitto Denko Corp
Publication of WO2025182448A1 publication Critical patent/WO2025182448A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
    • B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
    • B32B3/30—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by a layer formed with recesses or projections, e.g. hollows, grooves, protuberances, ribs
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/11—Anti-reflection coatings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses

Definitions

  • the present invention relates to a laminated film, a method for manufacturing a laminated film, an optical member, and a method for manufacturing an optical member.
  • a low-refractive index layer having a porous structure on a substrate improves the light reflection efficiency and improves and maintains the intensity of light emitted from optical components such as lighting devices equipped with a light source and a light guide layer. Furthermore, optical components capable of distributing light by partially disposing a low-refractive index layer on a substrate to change the light extraction position have been produced. By using such an optical component, an optical component can be realized that can efficiently distribute light irradiated onto the light guide layer and extract desired light.
  • a technique in which a material having a porous structure is applied to the entire surface of a substrate, and then an ink (paint) containing a curable resin is selectively applied to form a low refractive index layer having a pattern shape on the substrate (for example, Patent Document 1).
  • An object of the present invention is to provide a laminated film that can suppress defects in the pattern shape of a low refractive index portion and can realize an optical member that allows for improved productivity.
  • a laminate film according to an embodiment of the present invention comprises a substrate having a first main surface and a second main surface opposite the first main surface; and a concave-convex layer disposed on the first main surface.
  • the concave-convex layer has convex portions formed by a surface protection film and concave portions formed by low refractive index portions disposed between the convex portions.
  • the low refractive index portions have a porous structure.
  • the ratio of the total area of the concave portions to the total area of the concave-convex layer as viewed in the thickness direction of the laminate film is 50% or less.
  • the low refractive index portion may be disposed on a first main surface of the substrate.
  • the low refractive index portion may be formed in an island shape in a plan view when viewed from the thickness direction.
  • the low refractive index portion may have an equivalent diameter of an equal-circumference ellipse in plan view of 1 ⁇ m or more and 500 ⁇ m or less.
  • the surface protective film may include a film layer and a pressure-sensitive adhesive layer disposed on the substrate side of the film layer. The thickness of the low refractive index portion may be smaller than the thickness of the film layer.
  • the thickness of the low refractive index portion may be smaller than the thickness of the pressure-sensitive adhesive layer.
  • the method for producing the laminated film includes a through hole forming step of forming a through hole in the surface protective film, a disposing step of disposing the surface protective film having the through hole formed therein on the substrate, and a low refractive index portion forming step of applying a low refractive index portion forming material to an area of the substrate exposed by the through hole to form a low refractive index portion.
  • the low refractive index portion forming step may include applying the low refractive index portion forming material by spraying.
  • An optical element according to another aspect of the present invention includes a substrate and a plurality of low refractive index portions disposed on a main surface of the substrate.
  • the low refractive index portions have a porous structure.
  • a ratio of the area of the low refractive index portions to the total area of the main surface of the substrate and the low refractive index portions as viewed in a thickness direction of the optical element is 50% or less.
  • the low refractive index portion may be formed in an island shape in a plan view when viewed in the thickness direction.
  • the low refractive index portion may have an equivalent diameter of an equal-circumference ellipse in the plan view of 1 ⁇ m or more and 500 ⁇ m or less.
  • the method for manufacturing the optical member includes a through-hole forming step of forming a through-hole in a surface protective film that protects the substrate, a disposing step of disposing the surface protective film having the through-hole formed therein on the substrate, a low-refractive-index portion forming step of forming a low-refractive-index portion by applying a low-refractive-index portion forming material to an exposed portion of the substrate due to the through-hole, and a peeling step of peeling off the surface protective film after the low-refractive-index portion forming step.
  • the low refractive index portion forming step may include applying the low refractive index portion forming material by spraying.
  • Embodiments of the present invention provide a laminated film that can suppress defects in pattern shape and realize optical components that enable improved productivity, as well as optical components in which defects in pattern shape are suppressed.
  • FIG. 1 is a schematic cross-sectional view of a laminated film according to one embodiment of the present invention.
  • FIG. 2 is a schematic plan view of the laminated film according to the embodiment of the present invention, as viewed from the thickness direction. 1 is a schematic cross-sectional view of an optical element according to one embodiment of the present invention.
  • FIG. 2 is a schematic plan view of the optical member according to the embodiment of the present invention as viewed in the thickness direction.
  • FIG. 2 is a schematic partial perspective view showing an example of a part of one step (arrangement step) of the method for producing a laminated film according to the embodiment of the present invention.
  • FIG. 2 is a schematic partial cross-sectional view showing an example of a part of one step (arrangement step) of the method for producing a laminated film according to the embodiment of the present invention.
  • FIG. 2 is a schematic cross-sectional view showing an example of a part of one step (low refractive index portion forming step) in the method for producing the laminated film according to the embodiment of the present invention.
  • FIG. 2 is a schematic cross-sectional view showing an example of a part of one step (peeling step) of the method for manufacturing an optical member according to the embodiment of the present invention.
  • FIG. 2 is a schematic partially enlarged plan view of a laminated film according to an embodiment of the present invention, viewed from the thickness direction, illustrating the concept of dot diameter and pitch in the laminated film.
  • FIG. 2 is a diagram showing the surface state in a plan view of the laminated film in Example 1, which was observed with a laser microscope and image-processed.
  • FIG. 10 is a diagram showing the surface state in a plan view of the laminated film in Example 2, which was observed with a laser microscope and image-processed.
  • FIG. 10 is a diagram showing the surface state in a plan view of the laminated film in Example 3, which was observed with a laser microscope and image-processed.
  • FIG. 10 is a diagram showing the surface state in a plan view of a laminated film in Example 4, which was observed with a laser microscope and image-processed.
  • FIG. 1A is a schematic cross-sectional view of a laminated film according to one embodiment of the present invention.
  • the illustrated laminated film 100 comprises a substrate 10 having a first major surface 10a and a second major surface 10b opposite the first major surface 10a; and an uneven layer 2 disposed on the first major surface 10a.
  • the uneven layer 2 has convex portions 2a formed by a surface protective film 30 and concave portions 2b formed by low refractive index portions 20 disposed between the convex portions 2a.
  • the low refractive index portions 20 have a porous structure.
  • the ratio of the total area of the concave portions 2b to the total area of the uneven layer 2 as viewed from the thickness direction of the laminated film 100 (as viewed from above in the illustrated example) is 50% or less.
  • the amount of ink used for penetration increases and the spacing between the inks becomes closer, which can lead to interference between the inks in adjacent pattern shapes and result in defective pattern shapes.
  • the surface protection film in the laminate film according to an embodiment of the present invention has through holes formed therein, which can correspond to the recesses in the uneven layer. Furthermore, when the surface protection film is placed on the main surface of the substrate, exposed portions of the substrate are formed at positions on the main surface of the substrate corresponding to the through holes (hereinafter, sometimes referred to as "exposed portions"). During the manufacturing process of the laminate film, low refractive index portions are formed in the through holes (exposed portions). Since the low refractive index portions are typically significantly thinner than the surface protection film, the low refractive index portions constitute the recesses in the uneven layer. Thus, in the laminate film according to an embodiment of the present invention, the surface protection film functions as a mask for selectively forming low refractive index portions.
  • the laminate film according to an embodiment of the present invention is used to manufacture optical components, not only is the need for ink to be infiltrated to selectively form low refractive index portions, as in the prior art, unnecessary, but the amount of material used to form the low refractive index portions can also be reduced.
  • the convex portions can be made not to function as low-refractive index portions, and there is no need to fill the surface protection film with ink or the like (to prevent them from functioning as low-refractive index portions).
  • patterning of the low-refractive index portions does not involve ink penetration and is not affected by ink interference, etc., so defects in the pattern shape of the low-refractive index portions can be suppressed. Therefore, by using the laminate film according to an embodiment of the present invention, defects in the pattern shape of the low-refractive index portions can be suppressed, and optical components can be realized at low cost and with improved productivity.
  • Figure 1B is a partial plan view of a laminate film 100 according to one embodiment of the present invention.
  • the area of the uneven layer 2 in plan view is the entire area of the laminate film 100.
  • the uneven layer 2 is formed on one side (first main surface 10a) of the main surfaces of the substrate 10, but the uneven layer may also be formed on the second main surface 10b, or on both the first and second main surfaces.
  • the ratio of the total area of the recesses 2b to the total area of the uneven layer 2 when viewed in the thickness direction of the laminated film 100 is preferably 40% or less, more preferably 30% or less, and even more preferably 25% or less.
  • the lower limit of the ratio of the total area of the recesses 2b to the total area of the uneven layer 2 is, for example, more than 0%, and is preferably 1% or more, more preferably 3% or more, and even more preferably 5% or more.
  • the low refractive index sections 20 are arranged between the convex sections 2a of the uneven layer 2, forming concave sections 2b.
  • the low refractive index sections 20 are preferably arranged on the first major surface 10a of the substrate 10. "Arranged on the first major surface of the substrate” means "arranged in contact with the first major surface of the substrate.”
  • the low refractive index portions are preferably formed in an island shape in plan view when viewed in the thickness direction of the laminate film. Forming the low refractive index portions in an island shape can contribute to further improving the light extraction efficiency of optical components that can be fabricated from laminate films according to embodiments of the present invention. "Island shape" means that, in plan view, multiple low refractive index portions are not continuous but are arranged at intervals. In a laminate film according to one embodiment of the present invention, multiple low refractive index portions are formed in an island shape by forming through holes patterned in an island shape in the surface protection film.
  • the equivalent isocircular diameter of the low refractive index portion in plan view is preferably 1 ⁇ m or more and 500 ⁇ m or less. Having the equivalent isocircular diameter of the low refractive index portion in plan view within this range has the advantage of providing a laminate film that can realize optical components with higher-resolution patterns.
  • the "equivalent isocircular diameter of the low refractive index portion in plan view” refers to the diameter of a circle, assuming that the shape of the recess constituting the low refractive index portion on the surface (plane) in plan view is circular.
  • the equivalent isocircular diameter of the low refractive index portion in plan view is more preferably 2 ⁇ m or more, even more preferably 5 ⁇ m or more, and particularly preferably 10 ⁇ m or more.
  • the equivalent isocircular diameter of the low refractive index portion in plan view is more preferably 300 ⁇ m or less, even more preferably 250 ⁇ m or less. If the shape of the recess in plan view is elliptical, the equivalent isocircular diameter refers to the major diameter of the ellipse. If the shape of the recess in plan view is polygonal, the equivalent isocircular diameter refers to the diameter of the inscribed circle.
  • An optical element according to an embodiment of the present invention comprises a substrate and a plurality of low refractive index portions disposed on a major surface of the substrate.
  • Optical element 101 shown in FIG. 2A comprises a substrate 10 and a plurality of low refractive index portions 20 disposed on a major surface (first major surface 10a in FIG. 2A) of the substrate 10.
  • the low refractive index portions have a porous structure.
  • the ratio of the area of the low refractive index portions to the total area of the major surface of the substrate and the low refractive index portions as viewed in the thickness direction of the optical element is 50% or less.
  • Optical elements according to embodiments of the present invention may typically have a light distribution function.
  • the light distribution function refers to, for example, a function in which a laminate film is disposed on a light guide layer, and a portion of the light from the light source is totally reflected by a low refractive index portion, partially blocking the light from exiting from one side of the light guide layer, thereby allowing a portion of the light to exit the light guide layer from a location where the low refractive index portion is not provided, thereby adjusting the light intensity and thereby changing the degree of light extraction depending on the position of the light guide layer from the light source. Achieving light distribution can contribute to uniforming the brightness of the light emitted from the light guide layer.
  • the low refractive index portion of the laminate film can be easily patterned, and finer patterns can be easily achieved. Therefore, according to the optical member of the present invention, defects in the pattern shape can be suppressed. Furthermore, according to the optical member of the present invention, the low refractive index portion can be favorably miniaturized, and therefore, highly efficient light distribution can be realized.
  • the optical member according to the embodiment of the present invention has a configuration in which the surface protection film is peeled off from the laminate film. That is, the optical member according to the embodiment of the present invention can be produced by peeling off the surface protection film, which serves as a mask for forming the low refractive index portion, from the laminate film.
  • the substrate and the low refractive index portion in the optical member according to the embodiment of the present invention may correspond to the substrate and the low refractive index portion in the laminate film, respectively.
  • the same configuration as the laminate film will be omitted as appropriate, and the description of the laminate film described below will be used.
  • the substrate (and consequently the laminate film and optical component) may have any suitable shape.
  • the substrate may be, for example, long or sheet-like. In the illustrated example (e.g., FIG. 3A ), the substrate 10 is long and can be wound into a roll.
  • the term "long” refers to an elongated shape in which the length is sufficiently longer than the width, and includes, for example, an elongated shape in which the length is 10 times or more, preferably 20 times or more, the width.
  • the substrate may be, for example, a resin film.
  • Any appropriate resin material may be used as the material constituting the resin film.
  • the resin material constituting the resin film such as the main component, include transparent resins such as cycloolefin (COP) resins (e.g., polynorbornene), polyester resins (e.g., polyethylene terephthalate (PET)), polycarbonate (PC), (meth)acrylic, polyvinyl alcohol, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, polyolefin, and acetate.
  • COP cycloolefin
  • PET polyethylene terephthalate
  • PC polycarbonate
  • (meth)acrylic polyvinyl alcohol, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, polyolefin, and acetate.
  • thermosetting resins or ultraviolet-curing resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone.
  • (meth)acrylic resin refers to acrylic resin and/or methacrylic resin.
  • Other examples include glassy polymers such as siloxane polymers.
  • the resin film may be, for example, an extrusion molded product of the above-mentioned resin material or resin composition.
  • the resin film materials may be used alone or in combination.
  • the resin material that makes up the resin film may further contain additives. Examples of additives include antioxidants, UV absorbers, light stabilizers, nucleating agents, fillers, pigments, surfactants, and antistatic agents.
  • the substrate may have any appropriate thickness.
  • the thickness of the substrate is 6 ⁇ m or more and 1 mm or less.
  • the thickness of the substrate is preferably 10 ⁇ m or more, more preferably 15 ⁇ m or more, and even more preferably 20 ⁇ m or more.
  • the thickness of the substrate may typically be 100 ⁇ m or less.
  • the uneven layer is disposed on the first main surface of the substrate.
  • the uneven layer has convex portions and concave portions between the convex portions.
  • the convex portions are formed by a surface protective film.
  • the concave portions are formed by low refractive index portions disposed between the convex portions. That is, the thickness of the surface protective film is greater than the thickness of the low refractive index portions.
  • the pattern shape of the uneven layer (effectively, the low refractive index portion) can be any appropriate pattern depending on the purpose.
  • the pattern shape of the uneven layer can be controlled, for example, based on the shape, number, and position of the through-holes in the surface protection film that serves as a mask.
  • Specific examples of the pattern shape of the uneven layer include circular, elliptical, rectangular, and polygonal shapes for the shapes of the recesses (low refractive index portions) in a planar view.
  • Specific examples of the pattern shape of the uneven layer include an arrangement in which the recesses in a planar view are spaced approximately equally apart in the length and width directions between adjacent recesses.
  • the longitudinal and widthwise distances between adjacent recesses in the plane of the laminate film according to an embodiment of the present invention are preferably each independently 2 ⁇ m or more and 5000 ⁇ m or less.
  • the pattern shape of the low refractive index portion in the laminate film according to an embodiment of the present invention can be made finer.
  • the longitudinal distance and widthwise distance refer to the distance between the centers (area centers of gravity) of adjacent recesses.
  • the pattern shape of the uneven layer 2 is such that, when viewed in a plane, the shape of the recesses 2b (low refractive index sections 20) is circular, and the arrangement of the recesses 2b (low refractive index sections 20) is such that the spacing between adjacent recesses 2b in the lengthwise and widthwise directions is equal.
  • the recesses are more preferably arranged in a grid pattern with approximately equal intervals in a planar view.
  • the low refractive index portions are arranged at approximately equal intervals in the length and width directions on the first main surface of the substrate.
  • the respective lengthwise and widthwise intervals are approximately equal to each other.
  • approximately equal intervals is not limited to strictly identical intervals, and an interval within a range of ⁇ 5 ⁇ m is acceptable as approximately equal intervals. The same applies to "approximately equal.”
  • the surface protection film in the laminate film according to an embodiment of the present invention is temporarily and removably attached to the substrate. That is, as described above, the surface protection film functions as a mask for selectively forming a low refractive index portion and can protect the surface (main surface) of the substrate until the optical component is put into use.
  • the surface protection film 30 in the illustrated example includes a film layer 31 and a pressure-sensitive adhesive layer 32.
  • the pressure-sensitive adhesive layer 32 can be disposed on the substrate 10 side of the film layer 31.
  • the surface protection film 30 is temporarily and removably attached to the substrate 10 via the pressure-sensitive adhesive layer 32.
  • the surface protection film (substantially the film layer 31 and the pressure-sensitive adhesive layer 32) constitutes the convex portions 2a of the uneven layer 2.
  • the longitudinal direction of the elongated surface protection film 30 and the longitudinal direction of the substrate 10 are substantially parallel.
  • the width of the long surface protection film 30 can be designed to be substantially the same as or larger than the width of the substrate 10 .
  • the surface protective film can be provided on one or both of the main surfaces (first main surface and second main surface) of the substrate.
  • the film layer of the surface protection film can be composed of any appropriate resin film.
  • materials for forming the resin film include ester-based resins such as polyethylene terephthalate-based resins, cycloolefin-based resins such as norbornene-based resins, olefin-based resins such as polypropylene, polyamide-based resins, polycarbonate-based resins, and copolymer resins of these. Ester-based resins (particularly polyethylene terephthalate-based resins) are preferred.
  • the thickness of the film layer is preferably 10 ⁇ m or more, more preferably 15 ⁇ m or more, and even more preferably 20 ⁇ m or more.
  • the upper limit of the film layer thickness can be, for example, 200 ⁇ m or less, preferably 150 ⁇ m or less, and more preferably 100 ⁇ m or less. Such a thickness has the advantage that deformation is less likely to occur even when tension is applied during transportation and/or lamination.
  • the adhesive layer is composed of an adhesive.
  • adhesives include adhesive compositions that use an acrylic resin, styrene resin, or silicone resin as a base resin, and blend this base resin with a crosslinking agent selected from isocyanate compounds, epoxy compounds, and aziridine compounds, as well as a silane coupling agent.
  • Acrylic adhesives are preferred from the standpoints of chemical resistance, adhesion (for example, to prevent penetration of solutions during immersion, as described below), and flexibility to adherends.
  • the thickness of the adhesive layer in the laminate film according to one embodiment of the present invention is smaller than the thickness of the film layer.
  • the thickness of the adhesive layer is, for example, 1 ⁇ m or more and 60 ⁇ m or less.
  • the thickness of the adhesive layer is preferably 2 ⁇ m or more, more preferably 3 ⁇ m or more, and even more preferably 5 ⁇ m or more.
  • the thickness of the adhesive layer is preferably 50 ⁇ m or less, more preferably 40 ⁇ m or less, and even more preferably 30 ⁇ m or less. If the thickness is within the above range, the adhesive layer can maintain a level of adhesion that allows temporary adhesion, and the incorporation of air bubbles between the substrate and the film layer can be suppressed. Furthermore, if the thickness is within the above range, problems such as the adhesive overflowing can be suppressed.
  • Low refractive index portion As described above, the low refractive index portion is disposed between the convex portions of the concave-convex layer. In the laminate film and optical member according to the embodiment of the present invention, a plurality of low refractive index portions may be disposed.
  • the refractive index of the low refractive index portion is lower than that of the substrate, for example.
  • the refractive index of the low refractive index portion is, for example, 1.30 or less, with the lower limit exceeding 1.00.
  • the refractive index of the low refractive index portion is preferably 1.13 to 1.28, more preferably 1.14 to 1.27, even more preferably 1.15 to 1.26, and particularly preferably 1.16 to 1.25. If the refractive index of the low refractive index portion is within this range, the substrate can have a low refractive index portion with a pattern shape on the first main surface side (more specifically, the exposed portion of the substrate through the through hole), and the light distribution function can be particularly well exhibited.
  • the refractive index refers to the refractive index measured at a wavelength of 550 nm.
  • the refractive index is a value measured, for example, by the method described in the Examples below.
  • the total light transmittance of the low refractive index portion is preferably 85% to 99%, more preferably 87% to 98%, and even more preferably 89% to 97%.
  • the haze of the low refractive index portion is preferably less than 5%, more preferably less than 3%.
  • the haze may be, for example, 0.1% or more, or 0.2% or more.
  • the thickness of the low refractive index portion is, for example, 0.1 ⁇ m or more, preferably 0.3 ⁇ m or more, more preferably 1.0 ⁇ m or more, even more preferably 1.2 ⁇ m or more, particularly preferably 1.5 ⁇ m or more, and especially preferably 1.8 ⁇ m or more.
  • the thickness of the low refractive index portion may be, for example, 2.2 ⁇ m or more, or may be, for example, 2.5 ⁇ m or more, or may be, for example, 2.8 ⁇ m or more.
  • the thickness of the low refractive index portion may be, for example, 10 ⁇ m or less, or may be, for example, 8 ⁇ m or less, or may be, for example, 6 ⁇ m or less, or may be, for example, 4 ⁇ m or less.
  • the pattern shape of the low refractive index portion can be made more precise.
  • the productivity can be further improved when optical elements are produced from the laminate film according to this embodiment of the present invention.
  • the optical element according to this embodiment of the present invention can particularly effectively exhibit its light distribution function and light intensity adjustment function.
  • the thickness of the low refractive index portion of the laminate film according to an embodiment of the present invention is smaller than the thickness of the surface protection film. Furthermore, the thickness of the low refractive index portion is preferably smaller than the thickness of the film layer of the surface protection film. Furthermore, the thickness of the low refractive index portion is preferably smaller than the thickness of the adhesive layer of the surface protection film.
  • the pattern shape of the low refractive index portion can be made more precise, further improving productivity when producing optical elements from the laminate film.
  • the optical element according to an embodiment of the present invention can particularly effectively exhibit the light distribution function and the light intensity adjustment function.
  • the ratio of the thickness of the film layer to the thickness of the low refractive index layer is preferably within the range of 1:1 to 2000:1. Within this ratio range, the effects of the laminate film and optical component can be more significantly achieved even when the thickness of the low refractive index portion in the laminate film and optical component is made significantly smaller than the thickness of the film layer.
  • the ratio of the thickness of the film layer to the thickness of the low refractive index layer in the laminate film is more preferably within the range of 1:1 to 1000:1, even more preferably 1:1 to 500:1, even more preferably 1:1 to 100:1, and particularly preferably 1:1 to 30:1.
  • the ratio of the thickness of the pressure-sensitive adhesive layer to the thickness of the low refractive index layer is preferably within the range of 0.1:1 to 600:1. Within this ratio range, the effects of the laminate film and optical component can be more significantly achieved even when the thickness of the low refractive index portion in the laminate film and optical component is made significantly smaller than the thickness of the pressure-sensitive adhesive layer.
  • the ratio of the thickness of the pressure-sensitive adhesive layer to the thickness of the low refractive index layer in the laminate film is more preferably within the range of 0.1:1 to 300:1, even more preferably 0.1:1 to 100:1, even more preferably 0.1:1 to 50:1, and particularly preferably 0.1:1 to 10:1.
  • the low refractive index portion has a porous structure. Any appropriate configuration can be adopted for the low refractive index portion that can achieve the desired characteristics described above.
  • Materials that form the low refractive index portion (hereinafter sometimes referred to as "materials for forming the low refractive index portion") can be, for example, materials described in International Publication No. 2004/113966, Japanese Patent Application Laid-Open No. 2013-254183, and Japanese Patent Application Laid-Open No. 2012-189802.
  • Typical examples of materials for forming low refractive index portions include silicon compounds.
  • silicon compounds include silica-based compounds; hydrolyzable silanes and their partial hydrolysates and dehydration condensates; silicon compounds containing silanol groups; and activated silica obtained by contacting silicate with acid or ion exchange resin.
  • Other examples of materials for forming low refractive index portions include organic polymers; polymerizable monomers (e.g., (meth)acrylic monomers and styrene-based monomers); and curable resins (e.g., (meth)acrylic resins, fluorine-containing resins, and urethane resins). These materials may be used alone or in combination of two or more.
  • the low refractive index portion may contain spaces such as voids or gaps within it.
  • the porosity of the low refractive index portion is preferably 20% to 60% by volume, more preferably 25% to 55% by volume, even more preferably 30% to 50% by volume, and particularly preferably 35% to 45% by volume.
  • the porosity is a value calculated using the Lorentz-Lorenz formula from the refractive index measured with an ellipsometer.
  • the size of the voids that can be contained in the low refractive index portion can be adjusted to the desired size depending on the purpose and application.
  • the size of the voids that can be contained in the low refractive index portion is, for example, 2 nm or more, preferably 5 nm or more, more preferably 10 nm or more, and even more preferably 20 nm or more.
  • the size of the voids that can be contained in the low refractive index portion is, for example, 500 nm or less, preferably 200 nm or less, and more preferably 100 nm or less. Note that the size of the voids refers to the diameter of the major axis of the void.
  • Pore size can be quantified using the BET test method.
  • a measurement sample e.g., a fabricated low refractive index portion
  • a specific surface area measurement device e.g., the ASAP2020 manufactured by Micromeritics
  • Nitrogen gas is then adsorbed onto the measurement sample, and an adsorption isotherm is drawn to determine the pore distribution. This allows the pore size to be evaluated.
  • the low refractive index portion having an internal space may be, for example, a porous layer made of a porous material and/or a layer that includes an air layer at least in part.
  • the low refractive index portion having an internal space includes at least one of the porous layer and the air layer.
  • the low refractive index portion typically contains aerogel and/or particles (for example, hollow fine particles and/or porous particles).
  • the low refractive index portion is preferably a nanoporous layer (specifically, a porous layer in which 90% or more of the pores have a diameter in the range of 1 ⁇ 10 ⁇ 1 nm to 1 ⁇ 10 3 nm).
  • Particles are typically composed of silica-based compounds.
  • particle shapes include spherical, plate-like, needle-like, string-like, and bunch-of-grapes shapes.
  • string-like particles include particles in which multiple spherical, plate-like, or needle-like particles are strung together like beads, short fiber-like particles (such as the short fiber-like particles described in JP 2001-188104 A), and combinations thereof.
  • String-like particles may be linear or branched.
  • bunch-of-grapes-shaped particles include particles in which multiple spherical, plate-like, and needle-like particles aggregate to form a bunch of grapes. The particle shape can be confirmed, for example, by observation using a transmission electron microscope.
  • An example of a low refractive index portion is a structure composed of one or more types of structural units that form a fine void structure, and in which these structural units are bonded together (for example, chemically bonded via catalytic action).
  • Examples of the shape of the structural units include particulate, fibrous, rod-like, and flat plate-like.
  • the structural units may have only one shape, or a combination of two or more shapes.
  • a specific example of a low refractive index portion is a porous layer composed of a porous body in which particles having micropores (hereinafter referred to as micropore particles) are chemically bonded to one another.
  • a porous layer can be obtained, for example, by chemically bonding the micropore particles to one another.
  • the shape of the micropore particles is not particularly limited and may be, for example, spherical or another shape.
  • the micropore particles may be, for example, sol-gel beaded particles, nanoparticles (e.g., hollow nanosilica/nanoballoon particles), nanofibers, etc.
  • Micropore particles typically include inorganic substances.
  • the micropore particles are, for example, micropore particles of a silicon compound, and the porous body is, for example, a porous silicone body.
  • the micropore particles of a silicon compound include, for example, a pulverized gel silica compound.
  • a low refractive index portion is a layer containing a fibrous material such as nanofibers, with spaces formed by the entanglement of this fibrous material.
  • Further examples of a low refractive index portion include a layer formed using hollow nanoparticles or nanoclay, and a layer formed using hollow nanoballoons or magnesium fluoride.
  • the low refractive index portion may be composed of a single constituent material, or multiple constituent materials.
  • the low refractive index portion may be composed of a single form of the above examples, or multiple forms of the above examples.
  • the porous layer may have an open-cell structure, for example, where the pores are interconnected.
  • An open-cell structure refers to a porous body (e.g., a porous silicone body) in which the pores are interconnected three-dimensionally, and can also be described as a state in which the pore spaces are continuous. Possessing an open-cell structure in a porous layer can increase porosity. It is difficult to form an open-cell structure using closed-cell particles with individual pore structures, such as hollow particles (e.g., hollow silica). However, when using silica sol particles (a pulverized gel-like silicon compound that forms a sol), the silica sol particles can have a three-dimensional dendritic structure.
  • the dendritic particles settle and deposit in the coating film (a coating film of a sol containing a pulverized gel-like silicon compound), allowing for the easy formation of an open-cell structure.
  • the porous layer preferably has a monolithic structure in which the open-cell structure includes a distribution of multiple pores.
  • a monolithic structure refers to a hierarchical structure that includes, for example, a structure with nano-sized pores and an open-cell structure where nano-sized pores are aggregated. With a monolithic structure, for example, it is possible to achieve both membrane strength through fine pores and high porosity through a coarse open-cell structure.
  • the monolith structure can be formed by controlling the pore distribution of the void structure generated in the gel (gel silicon compound) prior to pulverization into silica sol particles.
  • the monolith structure can be formed by controlling the particle size distribution of the pulverized silica sol particles to a predetermined size.
  • the particle size distribution can be measured, for example, using particle size distribution evaluation devices such as dynamic light scattering and laser diffraction methods, and electron microscopes such as scanning electron microscopes (SEM) and transmission electron microscopes (TEM).
  • the porous layer may contain pulverized gel compounds such as gel silicon compounds, and these pulverized particles are chemically bonded together.
  • the volume average particle size of the pulverized particles in the porous layer is, for example, 0.10 ⁇ m or more, preferably 0.20 ⁇ m or more, and more preferably 0.40 ⁇ m or more.
  • the volume average particle size of the pulverized particles in the porous layer is, for example, 2.00 ⁇ m or less, preferably 1.50 ⁇ m or less, and more preferably 1.00 ⁇ m or less.
  • the volume average particle size is an indicator of the particle size variation of the pulverized particles, and is determined by particle size distribution measurement.
  • the low refractive index portion may contain silicon atoms.
  • the silicon atoms contained in the low refractive index portion are preferably siloxane-bonded.
  • the proportion of unbonded silicon atoms is, for example, less than 50%, preferably 30% or less, and more preferably 15% or less.
  • the material for forming the low refractive index portion may be a coating liquid in which the above material is dispersed in a dispersion medium.
  • the dispersion medium can adjust the viscosity, etc., of the coating liquid to a suitable range. As a result, the coating properties when forming the low refractive index portion can be improved.
  • the dispersion medium may be a single solvent, or a mixed solvent containing multiple types of solvents.
  • the dispersion medium examples include alcohols such as ethanol, isopropyl alcohol, butanol, t-butanol, isobutyl alcohol, and 2-methoxyethanol (methyl cellosolve); esters such as ethyl acetate and butyl acetate; ethers such as diisopropyl ether and propylene glycol monomethyl ether; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; and aromatic hydrocarbons such as toluene.
  • alcohols are more preferred, and isobutyl alcohol is even more preferred.
  • the mass ratio of the dispersion medium to the total amount of the low refractive index portion forming material is, for example, 5 mass% or more, preferably 30 mass% or more, more preferably 40 mass% or more, and is, for example, 100 mass% or less, preferably 95 mass% or less, more preferably 60 mass% or less. If the content ratio of the dispersion medium is within the above range, the viscosity of the low refractive index portion forming material can be stably adjusted to a range suitable for spray coating.
  • the coating film (a coating film of a sol containing a pulverized gel-like silicon compound) can be formed using a coating liquid containing microporous particles, and the microporous particles can be chemically bonded to each other by heating (including drying) this coating liquid.
  • the coating liquid containing microporous particles is, for example, a suspension.
  • a catalyst crosslinking reaction accelerator
  • a catalyst that promotes crosslinking between the microporous particles (e.g., a dehydration condensation reaction of residual silanol groups that may be contained in the microporous particles) and/or a substance that generates a catalyst (crosslinking reaction accelerator) (catalyst generator) may be added to the coating liquid.
  • catalysts include photoactivated catalysts and thermally activated catalysts.
  • catalyst-generating substances include photocatalyst generators and thermal catalyst generators.
  • photocatalyst generators include photobase generators (catalysts that generate a basic catalyst upon light irradiation) and photoacid generators (substances that generate an acidic catalyst upon light irradiation).
  • the microporous particles may be a pulverized product of a gel-like compound (preferably a gel-like silicon compound), and the low refractive index portion may have a porous structure composed of a porous body (preferably a silicone porous body) containing the pulverized product of the gel-like compound.
  • Such microporous particles may have the three-dimensional structure of the gel-like compound before pulverization dispersed within the three-dimensional basic structure.
  • a structure based on the three-dimensional basic structure may be formed. Specifically, a new structure different from the three-dimensional structure of the gel-like compound may be formed.
  • the resulting low refractive index portion (porous structure) may have a refractive index as low as that of an air layer, for example.
  • the three-dimensional basic structure may be fixed, ensuring sufficient strength in the resulting low refractive index portion (porous structure). Details of the specific configuration and method of forming the low refractive index portion (porous structure) are described, for example, in International Publication No. WO 2019/151073, the disclosure of which is incorporated herein by reference.
  • the coating thickness of the coating liquid can be set according to the desired thickness of the low refractive index portion.
  • the heating temperature of the coating film (coating liquid) is, for example, 20°C or higher, and preferably 50°C or higher.
  • the heating temperature of the coating film (coating liquid) is, for example, 200°C or lower, and preferably 150°C or lower.
  • the heating time of the coating film (coating liquid) is, for example, 10 seconds or longer.
  • the heating time of the coating film (coating liquid) is, for example, 24 hours or shorter, preferably 1 hour or shorter, more preferably 30 minutes or shorter, and even more preferably 10 minutes or shorter.
  • a coating film that forms a void structure which is a precursor to a porous layer (void layer), is formed on the substrate.
  • the following describes the case where the particles are pulverized gel compounds.
  • a coating film can also be formed in the same way when the particles are not pulverized gel compounds.
  • the reason why a void structure suitable for the coating film is formed when the particles are pulverized gel compounds is speculated to be, for example, as follows. However, this speculation does not limit the method for forming the low refractive index portion.
  • the above particles are made by crushing a gel-like silicon compound, so the three-dimensional structure of the gel-like silicon compound before crushing is dispersed throughout the three-dimensional basic structure. For example, by spraying crushed gel-like silicon compound onto a substrate, a precursor to a porous structure based on the three-dimensional basic structure is formed. In other words, with the above method, a new porous structure (three-dimensional basic structure) is formed by spraying the crushed material, which differs from the three-dimensional structure of the gel-like silicon compound.
  • the low refractive index portion that is ultimately obtained can achieve a low refractive index that functions at the same level as an air layer, for example.
  • the laminated film according to an embodiment of the present invention can be produced, for example, by placing a surface protection film having through holes on the first main surface of the substrate and applying a low refractive index portion-forming material to the exposed portion of the substrate exposed by the through holes to form a low refractive index portion. More specifically, the laminated film according to an embodiment of the present invention can be produced, for example, as follows.
  • a surface protection film is prepared.
  • the surface protection film can be used as a mask for forming a pattern of low refractive index portions. Therefore, the surface protection film preferably has through holes formed in a desired pattern. Low refractive index portions can be formed in the exposed areas of the through holes.
  • the positions at which the through holes 33 are provided correspond to the positions at which it is desired to form the low refractive index portions, and as a result, correspond to the positions of the recesses 2b in the uneven layer 2.
  • the surface protection film 30 is placed on the substrate 10 (e.g., the first main surface 10a) (this step may be referred to as the placement step).
  • the surface protection film 30 is typically releasably attached to the substrate 10 via the adhesive layer 32, as described above.
  • a long surface protection film 30 having a plurality of through holes 33 arranged in a predetermined pattern is laminated onto a long substrate 10 by roll-to-roll lamination.
  • exposed portions 11 are formed as shown in Figure 3B.
  • a low refractive index portion is formed in the through-hole (exposed surface) (sometimes referred to as the low refractive index portion formation process).
  • a low refractive index portion formation material is applied to the exposed portion (see Figures 3B and 3C). Details of the low refractive index portion formation material are as explained in Section C-2 above.
  • the low refractive index portion can be formed, for example, by applying a liquid low refractive index portion-forming material (coating liquid) to the exposed portion of the substrate, with a surface protection film having through holes disposed on the main surface of the substrate interposed therebetween. More specifically, the low refractive index portion can be formed by heating the formed coating film.
  • the low refractive index portion can be composed of a dried, semi-cured, or cured product of a coating film made from the low refractive index portion-forming material or coating liquid.
  • any appropriate method can be used to apply the low refractive index portion forming material.
  • application methods include spraying (spray coating), roll coating, and spin coating; and printing methods such as inkjet printing and screen printing.
  • Any appropriate application device can be used for application.
  • application devices include spray coaters, roll coaters, spin coaters, dispensers, inkjet coaters, and screen printers.
  • the low refractive index portion formation material (coating liquid) is preferably applied by spraying (also simply referred to as spraying).
  • spraying also simply referred to as spraying.
  • the laminate film according to an embodiment of the present invention uses a surface protection film with through holes that function as a mask, so spraying can further reduce the amount of low refractive index portion formation material used. Furthermore, the surface protection film does not need to be filled with paint such as ink. As a result, by using the laminate film according to an embodiment of the present invention, optical components can be produced at low cost and with high productivity.
  • the above-mentioned low refractive index portion formation material can be suitably used for spraying.
  • spraying the above-mentioned low refractive index portion formation material is sprayed onto a substrate on which a surface protective film is disposed as a mask, and a coating film is formed on the exposed portions of the substrate.
  • the coating film can be formed on the exposed portions of the substrate by spraying, for example, while the substrate on which the surface protective film is disposed is being transported with a roll.
  • the low refractive index portion forming material is preferably sprayed onto the substrate so that the rate of change in solid content concentration satisfies the following formula (1). 1.3 ⁇ Solid content concentration change rate ⁇ 60 (1)
  • the viscosity [mPa ⁇ s] of the coating film 10 seconds after spraying satisfies the following formula (2): 0.0549e 1.2x ⁇ Viscosity of coating film 10 seconds after spraying ⁇ 0.0549e 3.3x (2)
  • e represents the Napier's number
  • x represents the solids concentration in the coating film 10 seconds after spraying.
  • the viscosity of the coating 10 seconds after spraying is specifically 3 mPa ⁇ s or more, preferably 5 mPa ⁇ s or more, more preferably 8 mPa ⁇ s or more, even more preferably 10 mPa ⁇ s or more, and especially preferably 15 mPa ⁇ s or more, and is, for example, 500 mPa ⁇ s or less, preferably 300 mPa ⁇ s or less, more preferably 200 mPa ⁇ s or less, and especially preferably 100 mPa ⁇ s or less. If the viscosity of the coating is within the above range, the transparency and thickness precision of the low refractive index portion can be further improved.
  • the viscosity of the material for forming the low refractive index portion before spraying is, for example, 0.5 mPa ⁇ s or more, preferably 1.0 mPa ⁇ s or more, and for example, 300 mPa ⁇ s or less, preferably 100 mPa ⁇ s or less. These viscosities can be calculated using an Anton-Paar rheometer.
  • the distance (coating distance) between the spray head that sprays the low refractive index portion forming material and the substrate can be adjusted as appropriate. As the distance between the spray head and the substrate increases, the rate of change in solids concentration increases, and as the distance between the spray head and the substrate decreases, the rate of change in solids concentration can decrease.
  • the distance (coating distance) between the spray head and the substrate is, for example, 30 mm or more, preferably 50 mm or more, and for example, 300 mm or less, preferably 200 mm or less.
  • the spray head sprays the low refractive index portion forming material while moving in a plane direction including the exposed surface of the substrate.
  • the atomization pressure of the spray is, for example, 100 kPa to 1000 kPa
  • the spray application rate is, for example, 0.1 mL/min to 20 mL/min
  • the movement speed of the spray head during spraying is, for example, 10 mm/sec to 1000 mm/sec.
  • the laminate film manufacturing method according to an embodiment of the present invention can include the above-mentioned step of forming the through holes (through hole forming step), the arrangement step, and the low refractive index portion forming step.
  • the laminate film manufacturing method is not limited to the above-described method and the above-described order.
  • forming the low refractive index portion further includes a step of heating and drying the coating film on the substrate.
  • the heating temperature is, for example, 60°C or higher, preferably 70°C or higher, and more preferably 80°C or higher, and for example, 200°C or lower, preferably 120°C or lower, and more preferably 100°C or lower.
  • the heating time is not particularly limited as long as the coating film can be sufficiently dried.
  • a crosslinking reaction occurs between the particles in the coating film during this process, thereby fixing the three-dimensional basic structure, allowing the finally obtained low refractive index portion to maintain sufficient strength and flexibility despite having a void structure.
  • An optical member according to an embodiment of the present invention includes a substrate and a plurality of low refractive index portions disposed on a major surface of the substrate.
  • the optical member 101 in the illustrated example includes a substrate 10 and a plurality of low refractive index portions 20 disposed on a first major surface 10a of the substrate 10.
  • the low refractive index portions 20 have a porous structure. Furthermore, the ratio of the total area of the low refractive index portions 20 to the total area of the major surface of the substrate 10 and the low refractive index portions 20 as viewed in the thickness direction of the optical member 101 is 50% or less.
  • the optical element is a member in which the surface protection film has been peeled off from the laminate film described above, and therefore may have a patterned low refractive index portion.
  • the substrate and low refractive index portion in the optical element according to this embodiment of the present invention are the same as those described in sections B and C-2 above.
  • the method for manufacturing an optical element includes a step of peeling off the surface protective film (also referred to as a peeling step) after producing a laminate film in the same manner as the method for manufacturing a laminate film described in Section D above (see Figure 4). That is, a method for manufacturing an optical element according to one embodiment of the present invention can include the through-hole forming step, the arrangement step, the low refractive index portion forming step, and the peeling step.
  • the long laminate (ultimately an optical element) obtained by the above manufacturing method can be cut to any appropriate size to form sheet-like optical elements of appropriate dimensions.
  • the low refractive index portion used in the Examples and Comparative Examples was formed on an acrylic film.
  • the resulting laminate of the acrylic film and the low refractive index portion was cut to a size of 25 mm x 50 mm.
  • the cut laminate was attached to the surface of a glass plate (thickness: 3 mm) via an adhesive.
  • the center of the back surface of the glass plate (diameter: approximately 20 mm) was filled in with a black oil paint pen to create a sample that did not reflect light from the back surface of the glass plate.
  • the sample was placed in an ellipsometer (VASE, manufactured by J.A. Woollam Japan), and the refractive index was measured at a wavelength of 550 nm and an incident angle of 50 to 80 degrees.
  • Thickness Measurement was performed using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name "MCPD-3000").
  • the dot diameter and pitch of the low refractive index portion were confirmed by observing the shape of the recesses of the uneven layer in a planar view in the laminated film using a laser microscope (model number VK-X1000) manufactured by KEYENCE Corporation, and processing the image to confirm the dimensions.
  • the dot diameter of the low refractive index portion is the diameter a of a circle (that is, the equivalent diameter of an ellipse with an equal circumference) when the shape of the recess in plan view is a circle, as shown in FIG.
  • the pitch refers to the distance between the centers of adjacent recesses in the length direction (or width direction) in a plan view, as shown in Fig. 5.
  • the distance between the centers of adjacent recesses in the length direction is referred to as the length direction pitch px
  • the distance between the centers of adjacent recesses in the width direction is referred to as the width direction pitch py.
  • pitches are simply referred to as pitches.
  • the number of patterns in the low refractive index portion is the number of patterns per 1 cm 2 and is calculated based on the dot diameter and pitch.
  • the area ratio of the low refractive index portion is calculated by observing the laminated film with a laser microscope, calculating the total area of the uneven layer and the total area of the recesses in a planar view based on the image processed, and then calculating the ratio of the total area of the recesses to the total area of the uneven layer.
  • IPA isopropyl alcohol
  • the pulverization process (high-pressure media-less pulverization) was performed using a homogenizer (manufactured by SMT Corporation, product name "UH-50"), and 1.85 g of the gel-like compound and 1.15 g of IPA in mixed solution D were weighed into a 5 cc screw bottle, and then pulverized for 2 minutes under conditions of 50 W and 20 kHz. This grinding process pulverized the gel-like silicon compound in the mixed solution D, and the mixed solution D became a pulverized sol solution E.
  • a homogenizer manufactured by SMT Corporation, product name "UH-50”
  • the volume average particle size which indicates the particle size variation of the pulverized material contained in sol solution E, was confirmed using a dynamic light scattering Nanotrac particle size analyzer (manufactured by Nikkiso Co., Ltd., UPA-EX150 model), and was found to be 0.50 to 0.70 ⁇ m.
  • sol solution E 0.015 g of a 1.5 wt % MEK (methyl ethyl ketone) solution of a photobase generator (Wako Pure Chemical Industries, Ltd., product name: WPBG266) and 0.005 g of a 5 wt % MEK solution of a bis-crosslinking accelerator ((trimethoxysilyl)hexane) were added in a ratio of 0.015 g to 0.75 g of sol solution E, thereby obtaining a coating solution 1 for forming a low refractive index portion.
  • the refractive index of the low refractive index portion formed using this coating solution was 1.2.
  • Example 1 Base film 1 was prepared as the substrate, protective film 1 was prepared as the surface protective film, and the coating liquid of Production Example 1 was prepared as the low refractive index portion forming material. Through holes were formed in the surface protection film so as to have a predetermined pattern shape with dot diameters shown in Table 1 and with equal pitches in the length direction and width direction. Subsequently, the surface protection film with the through holes formed therein was attached to the substrate via the pressure-sensitive adhesive layer of the surface protection film. Subsequently, a coating film of the low refractive index portion forming material was formed by spray coating the coating liquid of the low refractive index portion forming material of Production Example 1 into the through holes of the surface protective film. Specifically, the spray coating was performed as follows.
  • the low refractive index portion forming material and a substrate (hereinafter referred to as a laminate) to which a surface protective film having through holes was attached were set in a spray coater (manufactured by Apeiros, product name API-240 series).
  • the distance (coating distance) between the spray head (nozzle) and the substrate (exposed portion of the substrate) in the laminate was 125 mm.
  • the low refractive index portion forming material was spray coated onto the exposed portion of the substrate of the laminate under coating conditions of an atomization pressure of 100 kPa and a coating amount of 7 mL/min, to form a coating film on the exposed portion of the substrate.
  • the coating film on the exposed portion of the substrate in the laminate was dried at 90°C for 10 minutes, and then dried at 70°C for 24 hours. This resulted in a laminate film having a surface protection film constituting the convex portions and a concave-convex layer having low refractive index portions constituting the concave portions on the substrate.
  • the thickness of the low refractive index portions was 2.0 ⁇ m.
  • the resulting laminate film was subjected to the measurements and evaluations (1) to (3) above.
  • Examples 2 to 4 Laminated films were produced in the same manner as in Example 1, except that the dot diameter and pitch of the pattern shape of the through holes in the surface protective film were changed as shown in Table 1. The thickness of the low refractive index portion in each example is as shown in Table 1. The obtained laminated films were subjected to the same evaluations as in Example 1.
  • a base film 1 was prepared as the substrate, and the coating liquid of the above-mentioned Manufacturing Example 1 was prepared as the material for forming the low refractive index portion.
  • the material for forming the low refractive index portion was applied to the entire first main surface of the substrate, thereby producing a coating film (layer) made of the material for forming the low refractive index portion.
  • a paint (curable resin composition: urethane-based photocurable resin (product name KRM8904 by Daicel Allnex Corporation)) that penetrates into the low refractive index portion forming material was injected into the paint inlet of the inkjet device, and the paint was ejected by an inkjet method onto the coating film of the low refractive index portion forming material on the substrate so that the ejected droplets of the paint had the dot diameter and pitch shown in Table 1, thereby forming a coating film of the paint having a predetermined interval (pattern), and a laminate was produced.
  • the laminate was heated at 100°C for 5 minutes to perform heat aging. This allowed the paint to penetrate into the low refractive index layer (porous layer).
  • a laminate film was obtained in which the paint was filled into a portion of the low refractive index layer (porous layer) and had a patterned low refractive index portion.
  • the paint was filled into a portion of the low refractive index layer (porous layer) and had a patterned low refractive index portion.
  • no surface protective film was used.
  • the thickness of the low refractive index portion is as shown in Table 1.
  • the obtained laminate film was subjected to the same evaluation as in Example 1.
  • Base film 1 Glass substrate (acrylic film (manufactured by Corning Incorporated, product name EAGLE XG. Material: alkali-free glass, thickness: 0.7 mm.)
  • Protective film 1 Surface protective film (product name E-MASK, manufactured by Nitto Denko Corporation).
  • the examples of the present invention provide a laminated film that can suppress defects in pattern shape and realize optical components that can improve productivity.
  • Laminate films according to embodiments of the present invention can be suitably used to produce optical components. Furthermore, optical components according to embodiments of the present invention can be suitably used as optical components having a light distribution function.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Laminated Bodies (AREA)
  • Optical Elements Other Than Lenses (AREA)
  • Surface Treatment Of Optical Elements (AREA)

Abstract

L'invention concerne un film stratifié avec lequel il est possible de réaliser un élément optique dans lequel des défauts de forme de motif peuvent être supprimés et une productivité améliorée est possible. Le film stratifié selon un mode de réalisation de la présente invention comprend un matériau de base ayant une première surface principale et une seconde surface principale sur le côté opposé à la première surface principale, et une couche irrégulière disposée sur la première surface principale. La couche irrégulière a des parties en saillie composées d'un film de protection de surface, et une partie évidée composée d'une partie à faible indice de réfraction disposée entre les parties en saillie. La partie à faible indice de réfraction a une structure poreuse. Le rapport de la surface totale des parties évidées à la surface totale de la couche irrégulière vue depuis la direction de l'épaisseur du film stratifié est de 50% ou moins.
PCT/JP2025/003228 2024-02-27 2025-01-31 Film stratifié, procédé de production de film stratifié, élément optique et procédé de production d'élément optique Pending WO2025182448A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022025067A1 (fr) * 2020-07-28 2022-02-03 日東電工株式会社 Élément de guidage de lumière de dispositif d'éclairage, dispositif d'éclairage et matériau de construction
JP2022086908A (ja) * 2020-11-30 2022-06-09 日東電工株式会社 光学フィルムの製造方法、光学フィルム、光学部材、画像表示装置、光学部材の製造方法および画像表示装置の製造方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022025067A1 (fr) * 2020-07-28 2022-02-03 日東電工株式会社 Élément de guidage de lumière de dispositif d'éclairage, dispositif d'éclairage et matériau de construction
JP2022086908A (ja) * 2020-11-30 2022-06-09 日東電工株式会社 光学フィルムの製造方法、光学フィルム、光学部材、画像表示装置、光学部材の製造方法および画像表示装置の製造方法

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