Light shielding film and lens unit

Abstract

The present invention addresses the problem of providing a light-shielding film having both low reflectance and workability. [Solution] A light-shielding film provided with a substrate having light-shielding properties and a gloss-proof layer disposed so as to overlap the substrate, the gloss-proof layer being more transparent than the substrate, the light-shielding film having an optical density value of 4.0 or more at a wavelength of 380-780 nm (inclusive), at least one of the surfaces of the anti-gloss layer has a gloss of 0.0% or more and 10.0% or less at an incidence angle of 60 degrees, and the light-shielding film has a surface resistance value of 1.0 * 105 [Omega] / square or less.

Description

Technical Field

[0001] The present disclosure relates to a light-shielding film and a lens unit. Background Art

[0002] Light-shielding members are used as shutters, apertures, or gap adjustment members between multiple lenses in optical components such as smartphones and digital cameras. Light-shielding members are manufactured using, for example, a light-shielding film comprising a sheet-like substrate and a light-shielding layer superposed on the surface of the substrate.

[0003] For example, Patent Document 1 discloses a light-shielding film characterized by being essentially composed of an organic resin and a black material, the organic resin including a cured curable resin or a thermoplastic resin with a glass transition temperature of 150°C or higher. However, this light-shielding film has the disadvantage of having a high reflectivity.

[0004] Meanwhile, Patent Document 2 discloses a light-shielding film comprising a sheet-like substrate having light-shielding properties and an anti-gloss layer. The anti-gloss layer is arranged to overlap the substrate, has irregularities formed on the surface opposite the substrate, and is more transparent than the substrate. The anti-gloss layer contains a binder resin, filler particles dispersed in the binder resin, and a coloring component dispersed in the binder resin. The blackness of the light-shielding film is within a predetermined range. The provision of the anti-gloss layer achieves low reflectivity.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application No. 2010-534342

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2022-137471 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] The light-shielding film of Patent Document 2 maintains its blackness within a specified range simply by providing an anti-gloss layer with a surface irregularity, but the antistatic function of the light-shielding film has not been studied. The present inventors conducted research and found that the light-shielding film of Patent Document 2 has a low antistatic function, and can be affected by static electricity and other factors, causing it to adhere to undesirable locations, resulting in poor workability. Workability refers to the property of easily placing the light-shielding film in a desired location when used in optical components such as shutters.

[0011] The technical problem of the present disclosure is to provide a light-shielding film that achieves both low reflectivity and workability. In addition, the technical problem of the present disclosure is to provide a lens unit including the light-shielding film of the present disclosure.

[0012] Technical Solution

[0013] The present disclosure relates to the following contents.

[0014] [1] A light-shielding film comprising a substrate having light-shielding properties and an anti-gloss layer disposed overlapping the substrate, the anti-gloss layer being more transparent than the substrate, the light-shielding film having an optical density of 4.0 or greater at a wavelength of 380 nm to 780 nm, at least one surface of the anti-gloss layer having a glossiness of 0.0% to 10.0% at an incident angle of 60 degrees, and a surface resistance of 1.0×10 5 Ω / □ or less.

[0015] [2] The light-shielding film according to [1], wherein the base material has antistatic properties.

[0016] [3] The light-shielding film according to [1] or [2], wherein the substrate contains carbon black.

[0017] [4] The light-shielding film according to any one of [1] to [3], wherein the gloss-proofing layer contains carbon black, and the content of the carbon black in the gloss-proofing layer is greater than 0% by mass and not more than 5% by mass.

[0018] [5] The light-shielding film according to any one of [1] to [4], wherein the gloss-proofing layer contains a binder resin and particles dispersed in the binder resin.

[0019] [6] The light-shielding film according to any one of [1] to [5], wherein the thickness of the light-shielding film is 35 μm or less.

[0020] [7] The light-shielding film according to any one of [1] to [6], wherein the thickness of the substrate is 2 μm or more and 30 μm or less.

[0021] [8] The light-shielding film according to any one of [1] to [7], wherein the anti-glare layer has a thickness of 1 μm to 7 μm.

[0022] [9] The light-shielding film according to any one of [1] to [8], wherein the light-shielding film is a shutter of an optical component, an aperture member, or a gap adjustment member arranged between a plurality of lenses.

[0023]

[10] A lens unit comprising the light-shielding film according to [9].

[0024] Effects of the Invention

[0025] According to the present disclosure, a light-shielding film having both low reflectivity and workability is provided. In addition, a lens unit including the light-shielding film of the present disclosure is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a cross-sectional view of a light-shielding film according to one embodiment of the present disclosure.

[0027] Figure 2 4 is a cross-sectional view of a light-shielding film according to one embodiment of the present disclosure.

[0028] Figure 3 1 is an exploded view of a lens unit according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] The present disclosure is described below based on specific embodiments. It should be noted that, in this specification, when the lower limit and upper limit of a numerical range are described separately, the numerical range may be a combination of any lower limit and any upper limit therein. In this disclosure, a numerical range represented by "A to B" means a numerical range that includes the lower limit and upper limit as endpoints.

[0030] In the present disclosure, Ω / □, which is a unit of surface resistance value, represents Ω / square.

[0031] The light-shielding film disclosed herein comprises a substrate having light-shielding properties and an anti-gloss layer disposed overlapping the substrate. Furthermore, the anti-gloss layer is more transparent than the substrate. Furthermore, the light-shielding film has an optical density of 4.0 or greater at a wavelength of 380 nm to 780 nm. Furthermore, at least one of the surfaces of the anti-gloss layer has a glossiness of 0.0% to 10.0% at an incident angle of 60 degrees. Furthermore, the light-shielding film has a surface resistance of 1.0×10 5 Ω / □ or less.

[0032] As described above, the substrate has light-shielding properties, and the gloss-blocking layer is more transparent than the substrate. This allows the gloss-blocking layer to be seen through, allowing the substrate's light-shielding properties to be exerted externally. The result is a light-shielding film with low brightness and excellent light-shielding properties. Furthermore, an optical density of 4.0 or higher at a wavelength of 380 nm to 780 nm indicates a high degree of blackness, a jet-black appearance, and excellent light-shielding properties.

[0033] Furthermore, if at least one of the surfaces of the gloss-blocking layer has a glossiness of 0.0% or more and 10.0% or less at an incident angle of 60 degrees, the gloss-blocking layer has excellent gloss-blocking properties. This facilitates reducing the reflectivity of the light-shielding film. Furthermore, the surface resistance of the light-shielding film is 1.0×10 5Ω / □ or less indicates that the antistatic function of the light-shielding film is high, thereby easily becoming a light-shielding film with excellent workability.

[0034] The light-shielding film disclosed herein can be used as a shutter of an optical component, an aperture member, or a gap adjustment member disposed between a plurality of lenses.

[0035] Figure 1 1 is a cross-sectional view of a light-shielding film 100 according to one embodiment of the present disclosure. The light-shielding film 100 includes a substrate 101 having light-shielding properties and an anti-gloss layer 102 arranged to overlap the substrate. Figure 1 In the embodiment, the first and second anti-gloss layers are laminated on both sides of the substrate 101. However, the anti-gloss layer may be laminated only on one side of the substrate 101 having light-shielding properties.

[0036] (Base material)

[0037] The substrate supports the anti-glossy layer. The substrate may be a single layer or may have multiple layers. When the substrate is a single layer, the material used for the substrate is not particularly limited, but preferably contains a resin and a colorant. The resin is not particularly limited, but preferably is one or more resins selected from the group consisting of polyethylene terephthalate (PET), polyimide (PI), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), polycarbonate (PC), and ethylene-methacrylic acid copolymer (EMAA), with PET being more preferred.

[0038] When the substrate is a single layer and contains a resin, the content of the resin in the substrate is not particularly limited, but is preferably 50% by mass to 100% by mass, and more preferably 60% by mass to 100% by mass.

[0039] There is no particular limitation on the colorant, and examples thereof include carbon black. There is no particular limitation on the carbon black, and examples thereof include conductive carbon blacks such as furnace black, thermal black, lamp black, acetylene black, and Ketjen black. As a colorant, from the viewpoint of adjusting the surface resistance value of the substrate, conductive particles such as conductive carbon black are preferred, and conductive carbon black is more preferred. As conductive carbon black, specifically, for example, DENKA BLACK (registered trademark) (manufactured by DENKA Co., Ltd.), KETJENBLACK EC (manufactured by LION SPECIALTY CHEMICALS Co., Ltd.), and KETJENBLACK EC-600D (manufactured by LION SPECIALTY CHEMICALS Co., Ltd.). In addition, a dispersion of conductive carbon black may also be used, and for example, MHIBlack#273 (manufactured by Mikoku Pigments Co., Ltd.) may be cited.

[0040] When the substrate is a single layer and contains a colorant, the content of the colorant in the substrate is not particularly limited, but is preferably greater than 0% by mass and less than 50% by mass, and more preferably greater than 1% by mass and less than 40% by mass. Within the above range, the light-shielding properties of the substrate are appropriate.

[0041] When the substrate is a single layer and contains a colorant, and the colorant is carbon black, the carbon black content in the substrate is not particularly limited, but is preferably greater than 0% by mass and less than 50% by mass, more preferably 1% by mass and less than 40% by mass, further preferably 10% by mass and less than 40% by mass, and particularly preferably 25% by mass and less than 40% by mass. Within the above range, the conductivity of the substrate is more appropriate, and the surface resistance value of the light-shielding film is likely to fall within the range described below.

[0042] Furthermore, as described above, the substrate has light-shielding properties. Here, having light-shielding properties means that, with respect to the substrate, the optical density value described later is 2.0 or greater. Furthermore, with respect to the substrate, the optical density value is preferably 3.0 or greater, more preferably 4.0 or greater. The upper limit is not particularly limited and may be 3.0 or greater and 10.0 or less, or 4.0 or greater and 10.0 or less. By using a material having light-shielding properties as the material for the substrate, a substrate having light-shielding properties can be obtained. For example, metal foils such as aluminum foil or substrates containing colorants can serve as substrates having light-shielding properties.

[0043] Alternatively, the substrate may have a plurality of layers, and one or more of the layers may have light-shielding properties, thereby providing a substrate having light-shielding properties.

[0044] The substrate may also contain conductive particles other than conductive carbon black. Such conductive particles are not particularly limited, and examples thereof include particles of metals such as gold, silver, copper, and nickel. By incorporating such conductive particles into the substrate, the surface resistance of the substrate can be easily adjusted to within the range described below.

[0045] The content of conductive particles other than conductive carbon black in the substrate is not particularly limited, but is preferably greater than 0% by mass and less than 50% by mass, more preferably from 1% by mass to less than 40% by mass, further preferably from 10% by mass to less than 40% by mass, and particularly preferably from 25% by mass to less than 40% by mass. Within this range, the conductivity of the substrate is more appropriate, and the surface resistance of the light-shielding film is more likely to fall within the range described below.

[0046] The base material may contain other materials and may also include various additives such as antioxidants, ultraviolet absorbers, heat stabilizers, plasticizers, lubricants, flame retardants, etc.

[0047] The shape of the substrate is not particularly limited, and is preferably a film. The thickness of the substrate is not particularly limited, and may be, for example, 2 μm to 30 μm, 2 μm to 20 μm, or 5 μm to 15 μm.

[0048] The substrate preferably has antistatic properties. By making the substrate have antistatic properties, workability can be easily improved. The substrate having antistatic properties means that the surface resistance of the substrate is 1.0×10 11 Ω / □ or less.

[0049] Furthermore, the surface resistance of the substrate is more preferably 1.0×10 10 Ω / □ or less, more preferably 1.0×10 9 Ω / □ or less, particularly preferably 1.0×10 7 Ω / □ or less, more preferably 1.0×10 6 Ω / □ or less. If it is within the above range, it is easy to adjust the surface resistance value of the light shielding film to the range described below. The lower limit is not particularly limited and can be 1.0×10 -3 ~1.0×10 11 Ω / □、1.0×10 -2 ~1.0×10 10 Ω / □、1.0×10 -1 ~1.0×10 9 Ω / □、1.0×10 0 ~1.0×10 7 Ω / □、1.0×10 1 ~1.0×10 6 Ω / □.

[0050] The surface resistance value of the substrate can be adjusted by changing the type and content of the material used for the substrate. For example, if the substrate contains conductive particles, it is easy to set the surface resistance value of the substrate to the above range. In addition, when the substrate having light-shielding properties contains conductive particles, the surface resistance value can be reduced by increasing the content of conductive particles in the substrate or using conductive particles with high conductivity, and the surface resistance value can be increased by reducing the content of conductive particles or using conductive particles with low conductivity.

[0051] The method for measuring the surface resistance value of the substrate will be described later.

[0052] (Anti-gloss layer)

[0053] The gloss-proofing layer 102 is more transparent than the substrate 101. Whether the gloss-proofing layer 102 is more transparent than the substrate 101 can be confirmed by measuring the total light transmittance of the gloss-proofing layer 102 and the substrate 101. Specifically, if the total light transmittance of the gloss-proofing layer 102 is higher than the total light transmittance of the substrate 101, the gloss-proofing layer 102 can be said to be more transparent than the substrate 101. The total light transmittance refers to the light transmittance measured according to JIS K 7375:2008.

[0054] The total light transmittance of the substrate and gloss-proof layer can be adjusted by varying the types and contents of the materials used. For example, if the colorant content of the gloss-proof layer is lower than that of the substrate, the total light transmittance of the gloss-proof layer tends to be higher than that of the substrate.

[0055] The gloss-proofing layer 102 is disposed overlapping the substrate 101. The gloss-proofing layer 102 scatters light incident on the light-shielding film 100, thereby preventing the light-shielding film 100 from being glossy. The gloss-proofing layer 102 is not particularly limited as long as it can prevent the light-shielding film from being glossy. The gloss-proofing layer 102 preferably has irregularities on the surface opposite to the substrate 101. Such irregularities facilitate preventing the light-shielding film from being glossy.

[0056] The method for forming the unevenness is not particularly limited. For example, known methods can be used, such as a method of incorporating particles described below into the gloss-proofing layer, a method of transferring an uneven pattern onto the gloss-proofing layer, and a method of incorporating multiple binder resins into the gloss-proofing layer to form a phase-separated structure. The phase-separated structure can be formed, for example, by spinodal decomposition (wet spinodal decomposition) from the liquid phase of the coating liquid for forming the gloss-proofing layer. For details on the phase-separated structure, see, for example, Japanese Patent No. 6190581.

[0057] The material of the gloss-proof layer is not particularly limited, but preferably contains a binder resin and a colorant. The binder resin is not particularly limited, and may be one or more resins selected from the group consisting of thermoplastic resins, thermosetting resins, and photocurable resins.

[0058] When the gloss preventing layer contains a binder resin, the content of the binder resin in the gloss preventing layer is not particularly limited, but is preferably 40% by mass or more and 100% by mass or less, and more preferably 50% by mass or more and 90% by mass or less.

[0059] Examples of the thermoplastic resin include polyolefins, styrene resins, acrylic resins, vinyl chloride resins, polyvinyl alcohol resins, polyacetal resins, saturated polyester resins, polycarbonate resins, polyamide resins, polyimide resins, polysulfone resins, polyphenylene ether resins, polyphenylene sulfide resins, fluororesins, cellulose derivatives, and thermoplastic polyurethane resins.

[0060] Examples of thermosetting resins include phenolic resins, melamine resins, urea-formaldehyde resins, benzoguanamine resins, silicone resins, epoxy resins, unsaturated polyester resins, vinyl ester resins, and thermosetting polyurethane resins. Examples of thermosetting polyurethane resins include urethane resins and urethane acrylate resins. Among these, urethane acrylate resins are preferred.

[0061] Examples of photocurable resins include photocurable polyester resins, photocurable acrylic resins, photocurable epoxy (meth)acrylate resins, and photocurable urethane (meth)acrylate resins. "Photocurable" herein means the property that a monomer is polymerized and cured by light of a specific wavelength.

[0062] The colorant is not particularly limited, and an example thereof is carbon black. As the carbon black, the carbon black described in the description of the substrate can be used. From the perspective of adjusting the surface resistance value of the light-shielding film, conductive particles such as conductive carbon black are preferred, and conductive carbon black is more preferred.

[0063] When the gloss-proofing layer contains carbon black, the content of carbon black in the gloss-proofing layer is not particularly limited, but is preferably greater than 0% by mass and less than 5% by mass, and more preferably greater than 2% by mass and less than 5% by mass. Within the above range, the optical density of the light-shielding film tends to fall within the range described below.

[0064] The gloss-blocking layer preferably contains a binder resin and particles dispersed within the binder resin. This facilitates the formation of surface irregularities on the gloss-blocking layer, thereby preventing the light-shielding film from losing its gloss. The particles are not particularly limited, and examples include inorganic particles such as the aforementioned colorant particles, silica particles, and the aforementioned metal particles, and organic particles such as resin particles. Silica particles are preferred as inorganic particles. Furthermore, the particles may include the aforementioned conductive particles in addition to carbon black.

[0065] The content of the particles in the gloss preventing layer is not particularly limited, but is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

[0066] The thickness of the gloss-proof layer is not particularly limited, and may be, for example, 1 μm to 10 μm, or 1 μm to 7 μm.

[0067] As mentioned above, the substrate may have multiple layers. For example, Figure 2 FIG is a cross-sectional view of a light shielding film 100 according to one embodiment of the present disclosure. Figure 2 In the embodiment, the light-shielding substrate includes a base layer 103 and a light-shielding layer 104 arranged to overlap with the base layer 103. Furthermore, the light-shielding film 100 includes a light-shielding substrate and a gloss-proofing layer 102 arranged to overlap with the substrate. Figure 2 In the embodiment, the first light-shielding layer and the second light-shielding layer are stacked on both surfaces of the base layer 103 , but the light-shielding layer may be stacked on only one surface of the base layer 103 .

[0068] The material of the base layer is not particularly limited, but preferably contains a resin. That is, the base layer is preferably a resin layer. As the resin, the resin described in the column of the base material can be used. In the case where the base layer contains a resin, the content of the resin in the base layer is not particularly limited, but is preferably 80% by mass or more and 100% by mass or less, and more preferably 90% by mass or more and 100% by mass or less. The base layer may contain other materials and may also contain various additives such as antioxidants, ultraviolet absorbers, heat stabilizers, plasticizers, lubricants, flame retardants, etc.

[0069] The thickness of the base layer is not particularly limited, and may be, for example, 1 μm to 10 μm, or 1 μm to 7 μm.

[0070] The material of the light-shielding layer is not particularly limited, but preferably contains a binder resin and a colorant. The binder resin may be any of those listed in the "shielding layer" column. Furthermore, the colorant may be any of those listed in the "substrate" column and the "shielding layer" column. From the perspective of adjusting the surface resistance of the substrate, conductive particles such as conductive carbon black are preferred, and conductive carbon black is more preferred.

[0071] The light-shielding layer may contain the above-mentioned conductive particles other than the conductive carbon black.

[0072] From the perspective of ensuring good compatibility between the substrate and the gloss-proof layer, when the light-shielding layer and the gloss-proof layer contain a binder resin, the binder resin contained in the light-shielding layer and the binder resin contained in the gloss-proof layer are preferably the same type. For example, the binder resin contained in the light-shielding layer is preferably a urethane acrylate resin, and the binder resin contained in the gloss-proof layer is preferably a urethane acrylate resin. Furthermore, it is more preferred that the binder resin contained in the light-shielding layer and the binder resin contained in the gloss-proof layer are the same.

[0073] From the perspective of ensuring good compatibility between the substrate and the gloss-proof layer, when the light-shielding layer and the gloss-proof layer contain a colorant, the colorant contained in the light-shielding layer is preferably the same type as the colorant contained in the gloss-proof layer. For example, it is preferred that the colorant contained in the light-shielding layer is carbon black, and the colorant contained in the gloss-proof layer is carbon black. Furthermore, it is more preferred that the colorant contained in the light-shielding layer is the same as the colorant contained in the gloss-proof layer.

[0074] When the light-shielding layer contains a binder resin, the content of the binder resin in the light-shielding layer is not particularly limited, but is preferably 50% by mass to 100% by mass, and more preferably 60% by mass to 90% by mass.

[0075] When the light-shielding layer contains carbon black, the content of carbon black in the light-shielding layer is not particularly limited, but is preferably greater than 0 mass % and less than 50 mass %, more preferably greater than 10 mass % and less than 40 mass %, and further preferably greater than 15 mass % and less than 40 mass %.

[0076] The thickness of the light-shielding layer is not particularly limited, and may be, for example, 1 μm to 10 μm, or 1 μm to 5 μm.

[0077] As described above, the light-shielding film has an optical density of 4.0 or greater at a wavelength of 380 nm to 780 nm. The optical density is preferably 5.0 or greater, more preferably 6.0 or greater. Within this range, the light-shielding film easily exhibits excellent light-shielding properties. The upper limit is not particularly limited and may be 4.0 or greater and 10.0 or less, 5.0 or greater and 10.0 or less, or 6.0 or greater and 10.0 or less.

[0078] The optical density can be adjusted by varying the type and content of the light-shielding substrate and the material used for the gloss-blocking layer. Specifically, by including a light-shielding substrate and a gloss-blocking layer in the light-shielding film, the optical density can be easily adjusted to fall within the aforementioned range. Furthermore, if the light-shielding substrate contains a colorant, the optical density can be increased by increasing the colorant content in the substrate, while decreasing it can be reduced. Similarly, if the gloss-blocking layer contains a colorant, the optical density can be increased by increasing the colorant content in the gloss-blocking layer, while decreasing it can be reduced.

[0079] The method for measuring the optical density value will be described later.

[0080] As described above, at least one of the surfaces of the gloss-blocking layer has a glossiness of 0.0% to 10.0% at an incident angle of 60 degrees. The glossiness is preferably 0.0% to 5.0%, and more preferably 0.0% to 1.0%. Within this range, the gloss-blocking layer exhibits enhanced gloss-blocking properties. This facilitates reducing the reflectivity of the light-shielding film.

[0081] The glossiness can be adjusted, for example, by adjusting the type and content of the particles contained in the gloss-proof layer. Specifically, when inorganic particles such as silica particles are used as the particles, the glossiness can be easily adjusted to fall within the above range.

[0082] The method for measuring glossiness will be described later.

[0083] As mentioned above, the surface resistance of the light shielding film is 1.0×10 5 Ω / □ or less. The surface resistance value of the light-shielding film is preferably 5.0×104 Ω / □ or less, more preferably 1.0×10 4 Ω / □ or less. The lower limit is not particularly limited and can be 1.0×10 -3 Ω / □ or more, can be 1.0×10 -2 Ω / □ or more, can be 1.0×10 -1 Ω / □ or more. That is, the surface resistance value of the light shielding film can be, for example, 1.0×10 -3 ~1.0×10 5 Ω / □、1.0×10 -2 ~5.0×10 4 Ω / □、1.0×10 -1 ~1.0×10 4 Ω / □. If it is within the above range, the antistatic function of the light-shielding film is more excellent. As a result, it is easy to become a light-shielding film with excellent workability.

[0084] The surface resistance of the light-shielding film can be adjusted by changing the surface resistance of the substrate using the method described in the substrate's instructions. Furthermore, by ensuring good compatibility between the substrate and the gloss-blocking layer, the surface resistance of the light-shielding film can be easily adjusted to fall within the above range. The method for measuring the surface resistance of the light-shielding film will be described later.

[0085] The thickness of the light-shielding film is not particularly limited and may be, for example, 35 μm or less, or 30 μm or less. If the thickness of the light-shielding film falls within this range, the workability of the light-shielding film may be more easily reduced. However, the light-shielding film of the present disclosure can achieve excellent workability. The lower limit of the thickness of the light-shielding film is not particularly limited and may be 3 μm or more and 35 μm or less, 3 μm or more and 30 μm or less, or 8 μm or more and 20 μm or less.

[0086] <Lens Unit>

[0087] The lens unit includes the light-shielding film of the present disclosure. For example, the lens unit includes a light-shielding film and a lens.

[0088] Figure 3 is an exploded view of the lens unit 40. Figure 3 In FIG, the lens unit 40 includes: a plurality of light shielding members F1 to F6; a plurality of optical members (here, lenses L1 to L6); and a housing (lens barrel) 41 that houses the light shielding members F1 to F6 and the optical members. Figure 3 In the embodiment, the light shielding members F1 to F6 are arranged between adjacent optical members so as to surround the optical axis R of the optical member. The number of light shielding members and the number of optical members included in the lens unit 40 are not limited.

[0089] Light-shielding members F1-F6 have the same cross-sectional structure as the light-shielding film. Specifically, they comprise a light-shielding substrate and an anti-gloss layer superposed on the substrate. The light-shielding substrate can be any of the substrates described in the "Substrate" section above, and the anti-gloss layer can be any of the anti-gloss layers described in the "Anti-Gloss Layer" section above.

[0090] The lens unit disclosed herein can impart anti-glare properties to the light shielding members F1 to F6, scattering incident light from the outside through the anti-glare layer. Furthermore, reflection of incident light entering the anti-glare layer can be suppressed, effectively reducing the brightness of the anti-glare layer surface.

[0091] As described above, the gloss-blocking layer is more transparent than the base material. Therefore, the base material's light-shielding properties can be exerted to the outside through the gloss-blocking layer. As a result, the light-shielding members F1 to F6 can be realized with low brightness and excellent light-shielding properties.

[0092] Hereinafter, a method for measuring the physical properties of the light-shielding film of the present disclosure will be described.

[0093] <Method for measuring the optical density value of light-shielding film>

[0094] The optical density value of the light-shielding film at a wavelength of 380 nm to 780 nm was measured using a transmission densitometer ("341C type (transmission densitometer)" manufactured by Xrite).

[0095] <Method for measuring the glossiness of the anti-gloss layer>

[0096] The glossiness of the surface of the gloss-proofing layer at an incident angle of 60 degrees was measured using a gloss meter (manufactured by TQC, "RDK-12 / KT-GL0030 model").

[0097] <Measurement Method of Surface Resistivity>

[0098] The surface resistance values ​​of the light-shielding substrate and the gloss-blocking layer were measured using a Loresta (Mitsubishi Chemical "MCP-T610"). If the resistance exceeded the Loresta's upper limit, the surface resistance value was measured using an ultra-high resistance / micro-ammeter (Advantest Co., Ltd. "R8340"). The result obtained from the gloss-blocking layer surface measurement was used as the surface resistance value of the light-shielding film.

[0099] Each configuration and combination thereof in each embodiment is an example, and addition, omission, substitution, and other modifications of the configuration may be appropriately made without departing from the spirit of the present disclosure. The present disclosure is not limited to the embodiments but only to the claims.

[0100] Example

[0101] Hereinafter, the present disclosure will be described in detail with reference to examples, but the present disclosure is not limited to the following examples.

[0102] [Example 1]

[0103] A 6-μm-thick PET film (manufactured by Toray Industries, Ltd.) was used as the base layer. To 32 parts by mass of a binder resin, a urethane acrylate resin (manufactured by Kohshin-Chem, Ltd., "KDC-01 Main"), 3 parts by mass of an ink containing carbon black and a urethane acrylate resin (manufactured by Toyochem, Ltd., "E039 PET AKSB 92T") and 55 parts by mass of a carbon black dispersion (manufactured by Mikoku Pigments, Ltd., "MHI Black #273") were added. Furthermore, 10 parts by mass of a curing agent (manufactured by Mitsui Chemicals, Ltd., "TAKENATE A-3") were added to prepare a coating solution. The resulting coating solution was applied to both sides of the base layer and thermally cured to form a pair of light-shielding layers, each with a thickness of 1.5 μm after drying, resulting in a substrate with light-shielding properties.

[0104] Furthermore, 54 parts by mass of a urethane acrylate resin ("KDC-01 Main Agent" manufactured by Kohshin-Chem Co., Ltd.) as a binder resin were mixed with 6 parts by mass of an ink containing carbon black and a urethane acrylate resin ("E039 PET AKSB 92T" manufactured by Toyochem Co., Ltd.), 12.5 parts by mass of a curing agent ("Takenate A-3" manufactured by Mitsui Chemicals, Inc.), 7.5 parts by mass of silica particles ("Sylophobic 100" manufactured by Fuji Silysia Co., Ltd.), 15 parts by mass of a carbon black dispersion ("MHI Black #273" manufactured by Mikoku Pigments Co., Ltd.), and the remainder of the solvent (methyl ethyl ketone) to prepare a coating solution. The resulting coating solution was applied to both surfaces of a light-shielding substrate and thermally cured to form a pair of gloss-blocking layers each having a thickness of 3.5 μm after drying, thereby preparing a light-shielding film. The resulting light-shielding film was measured using the above-described method. The measurement results are shown in Table 1.

[0105] [Example 2]

[0106] A light-shielding film was obtained in the same manner as in Example 1 except that the amount of carbon black dispersion ("MHI Black #273" manufactured by Mikoku Pigments Co., Ltd.) used in forming the light-shielding layer was changed to 30 parts by mass. The obtained light-shielding film was measured in the same manner as in Example 1. The measurement results are shown in Table 1.

[0107] [Comparative Example 1]

[0108] A light-shielding film was obtained in the same manner as in Example 1, except that the amount of the urethane acrylate resin as the binder resin in forming the light-shielding layer was set to 38 parts by mass, the amount of the ink was set to 52 parts by mass, and no carbon black dispersion was used. The obtained light-shielding film was measured in the same manner as in Example 1. The measurement results are shown in Table 1.

[0109] [Comparative Example 2]

[0110] A light-shielding film was obtained in the same manner as in Example 1, except that a 12 μm-thick black film mixed with carbon black (manufactured by Nan Ya Plastics Co., Ltd.) was used as a light-shielding substrate and the gloss-blocking layer had a thickness of 5 μm after drying. The obtained light-shielding film was measured in the same manner as in Example 1. The measurement results are shown in Table 1.

[0111] [Comparative Example 3]

[0112] A light-shielding film was obtained in the same manner as in Example 1 except that the gloss-proofing layer was not formed. That is, a substrate having light-shielding properties was obtained in the same manner as in Example 1, and the obtained substrate was used as a light-shielding film.

[0113] The obtained light-shielding film was measured in the same manner as in Example 1. The measurement results are shown in Table 1.

[0114] [Comparative Example 4]

[0115] A light-shielding film was obtained in the same manner as in Example 1, except that an 8.5 μm-thick aluminum foil ("Nippaku Foil" manufactured by Mitsubishi Aluminum Co., Ltd.) was used as the light-shielding substrate and the gloss-blocking layer had a thickness of 2.25 μm after drying. The obtained light-shielding film was measured in the same manner as in Example 1. The measurement results are shown in Table 1.

[0116] [Comparative Example 5]

[0117] A light-shielding film was obtained in the same manner as in Example 1, except that the thickness of the base layer was set to 4.5 μm, the light-shielding layer was formed using a urethane binder resin ("Vylon 40SS" manufactured by Toyobo Co., Ltd.) and a carbon black dispersion ("MHI Black #273" manufactured by Mikoku Pigments Co., Ltd.), with the mass ratio of carbon black to the light-shielding layer being 12% by mass, and the gloss-proof layer was formed using a thermosetting binder resin ("KDC-03" manufactured by Kohshin-Chem Co., Ltd.), silica particles ("SYLYSIA 420" manufactured by Fuji Silysia Co., Ltd.), and a carbon black dispersion ("MHI Black #273" manufactured by Mikoku Pigments Co., Ltd.), with the mass ratio of carbon black to the gloss-proof layer being 4% by mass, and the thickness of the gloss-proof layer being 4.0 μm. The obtained light-shielding film was measured using the above-mentioned method. The measurement results are shown in Table 1.

[0118] [Table 1]

[0119] Table 1

[0120]

[0121]

[0122] In the table, OD value represents the optical density value.

[0123] In Examples 1 and 2, the surface resistance of the light-shielding film is 1.0×10 5 Ω / □ or less.

[0124] On the other hand, in Comparative Examples 1, 2, 4, and 5, the surface resistance of the light-shielding film exceeded 1.0×10 5 , insufficient antistatic function and low workability.

[0125] When the light-shielding film does not have a gloss-proof layer as in Comparative Example 3, the 60-degree glossiness is extremely high and low reflectivity cannot be achieved.

[0126] Industrial applicability

[0127] According to the present disclosure, a light-shielding film having both low reflectivity and workability can be provided. Furthermore, the light-shielding film of the present disclosure can be used in a lens unit.

[0128] Description of Reference Numerals

[0129] 40: lens unit; 41: housing; 100: light-shielding film; 101: substrate with light-shielding properties; 102: gloss-proof layer; 103: base layer; 104: light-shielding layer; F1 to F6: light-shielding members; L1 to L6: lenses; R: optical axis.

Claims

1. A light-shielding film comprising a substrate having light-shielding properties and an anti-gloss layer arranged to overlap with the substrate. The anti-gloss layer is more transparent than the substrate, The light-shielding film has an optical density of 4.0 or more at a wavelength of 380 nm or more and 780 nm or less. At least one of the surfaces of the anti-gloss layer has a glossiness of 0.0% or more and 10.0% or less at an incident angle of 60 degrees, The surface resistance of the light-shielding film is 1.0×10 5 Ω / □ or less.

2. The light-shielding film according to claim 1, wherein The substrate has antistatic properties.

3. The light-shielding film according to claim 1, wherein The substrate contains carbon black. The light-shielding film according to claim 1 , wherein: The gloss preventing layer contains carbon black, and the content of the carbon black in the gloss preventing layer is greater than 0% by mass and not more than 5% by mass. The light-shielding film according to claim 1 , wherein: The gloss-proof layer contains a binder resin and particles dispersed in the binder resin. The light-shielding film according to claim 1 , wherein: The light-shielding film has a thickness of 35 μm or less.

7. The light-shielding film according to claim 1, wherein The thickness of the substrate is 2 μm or more and 30 μm or less. The light-shielding film according to claim 1 , wherein The anti-gloss layer has a thickness of 1 μm or more and 7 μm or less.

9. The light-shielding film according to any one of claims 1 to 8, wherein The light shielding film is a shutter of an optical component, an aperture member, or a gap adjusting member disposed between a plurality of lenses. 10 . A lens unit comprising the light-shielding film according to claim 9 .

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