Black light-shielding member

Abstract

The present application provides a black light-shielding member having excellent low-gloss-based antireflection effect and high blackness. A black light-shielding member is manufactured, which has a base film, a resin light-shielding layer having a concave-convex shape formed on at least one surface of the base film, and a blackened layer formed on the resin light-shielding layer. By adjusting the surface arithmetic average roughness Ra of the surface on which the light-shielding layer and the blackened layer are formed to be 0.25 μm or more, and the maximum thickness of the blackened layer to be less than the above Ra, a blackness with an L value of 12 or less is achieved.

Description

Technical Field

[0001] This invention relates to a black light-shielding component, and more specifically, to a black light-shielding component applicable to optical devices such as camera units of mobile phones, including smartphones. Background Technology

[0002] Typically, light-shielding components are used in camera lenses, apertures, shutters, and lens pads.

[0003] As such a light-shielding component, it is known to form a black film with a prescribed uneven shape on the surface of a black polyester substrate such as carbon black. Examples of methods for forming the aforementioned unevenness include covering the substrate surface with a light-shielding layer containing a matting agent, and roughening the substrate surface by methods such as sandblasting.

[0004] Patent Document 1 describes a light-shielding component that, using the aforementioned method, has an arithmetic mean roughness Ra of 0.5 μm or more as measured by JIS B0601:2001, and the difference between the maximum peak height Rp and the maximum valley depth Rv (Rp-Rv) is less than 3. Even when very thin, the light-shielding component of Patent Document 1 exhibits excellent anti-reflection performance. Due to its excellent hardness and the tight adhesion between the light-shielding layer and the film substrate, it can maintain excellent anti-reflection performance over a long period.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. WO2018 / 052044 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] In recent years, there has been a search for components with a more pronounced black color for use in optical equipment as part of an effort to enhance design aesthetics. However, no satisfactory results have been achieved to date.

[0010] The present invention was made in view of the above circumstances, and its object is to provide a light-shielding component with excellent anti-reflective effect based on low gloss and high blackness.

[0011] Methods for solving problems

[0012] The inventors conducted in-depth research in view of the above-mentioned problems and found that by forming a black light-shielding member with a substrate film and a resin light-shielding layer with an uneven shape formed on at least one surface of the substrate film, and further controlling the uneven shape of the surface of the light-shielding member, the above-mentioned problems can be solved, and thus the present invention was conceived. Specifically, the black light-shielding member of the present invention comprises a substrate film, a resin light-shielding layer with an uneven shape formed on at least one surface of the substrate film, and a blackening layer formed on the resin light-shielding layer, characterized in that, in the black light-shielding member, the surface arithmetic mean roughness Ra of the surfaces on which the light-shielding layer and the blackening layer are formed is 0.25 μm or more, and the L value is 12 or less, and the maximum thickness of the blackening layer is less than Ra.

[0013] Here, a resin-based light-shielding layer refers to a layer in which at least the uneven portion of the surface forming the blackening layer is made of resin. For example, as described later, structures in which a light-shielding layer containing a matting agent and / or a light-shielding layer without a matting agent are formed on the surface of a metal substrate film with an uneven shape are also included in the resin-based light-shielding layer of the present invention.

[0014] Furthermore, the arithmetic mean roughness Ra described in this invention is calculated based on JIS B0601:2001, and the L value is calculated based on JIS Z8781-4. * a * b * Lightness (L) in color space * value.

[0015] Preferably, the above-mentioned resin-based light-shielding layer has a resin layer containing a matting agent and a resin component.

[0016] In addition, the aforementioned resin-based light-shielding layer may also include roughened portions formed on the surface of the substrate film.

[0017] On the other hand, preferably, the blackening layer contains inorganic materials.

[0018] Preferably, the blackening layer comprises at least one selected from magnesium fluoride, calcium fluoride, lithium fluoride, aluminum oxide, gallium oxide, and silicon oxide.

[0019] Furthermore, preferably, the aforementioned blackening layer is formed by any one of sputtering, vapor deposition, ion plating, or chemical vapor deposition (CVD).

[0020] Furthermore, preferably, the maximum thickness of the blackened layer is less than 1 / 2 of the arithmetic mean roughness Ra of the surface.

[0021] The effects of the invention

[0022] The black light-shielding component of this invention not only has excellent anti-reflective properties based on low gloss, but also boasts high blackness, a distinct black color, and a superior design aesthetic. Therefore, it is also suitable for use as a camera unit in mobile phones such as smartphones. Attached Figure Description

[0023] Figure 1 This is a cross-sectional schematic diagram showing the structure of the light-shielding member in one embodiment of the present invention ((a) before the formation of the blackening layer, (b) after the formation of the blackening layer).

[0024] Figure 2 This is a cross-sectional schematic diagram showing the structure of the light-shielding member in another embodiment of the present invention ((a) before the formation of the blackening layer, (b) after the formation of the blackening layer).

[0025] Label Explanation

[0026] 1. Light-shielding components (before the blackening layer forms)

[0027] 10. Light-shielding components (after blackening layer formation)

[0028] 2. Substrate film

[0029] 3. Light-shielding layer

[0030] 31 Matting Agent

[0031] 32 Matrix

[0032] 4. Light-shielding layer (resin film)

[0033] 5. Blackening layer Detailed Implementation

[0034] The embodiments of the present invention will now be described in detail.

[0035] Furthermore, in this specification, the "~" sign indicating a numerical range signifies a range that includes both an upper limit and a lower limit. Additionally, if only the upper limit is specified within a numerical range, it indicates that the lower limit also has the same unit as the upper limit.

[0036] The upper or lower limit of the numerical ranges recorded in this specification can also be the upper or lower limit of other numerical ranges recorded in different periods.

[0037] Furthermore, the upper or lower limit of the numerical range described in this specification may be replaced with the values ​​shown in the embodiments.

[0038] In this specification, the content or percentage of each component in the composition refers to the total content or percentage of the multiple substances present in the composition unless otherwise specified, when multiple substances equivalent to each component are present in the composition.

[0039] The embodiments of the present invention will now be described in detail.

[0040] The black light-shielding component of the present invention comprises a substrate film, a resin light-shielding layer having an uneven shape formed on at least one surface of the substrate film, and a blackening layer formed on the resin light-shielding layer. The black light-shielding component is characterized in that the surface arithmetic mean roughness Ra of the surfaces on which the light-shielding layer and the blackening layer are formed is 0.25 μm or more, and the blackness (L value) is 12 or less, and the maximum thickness of the blackening layer is less than Ra.

[0041] First, with reference to the accompanying drawings, the uneven shape of the resin-based light-shielding layer of the present invention will be described.

[0042] Methods for forming the uneven shape of the resin-based light-shielding layer include (A), (B), and (C).

[0043] In method (A), such as Figure 1 As shown in (a), a light-shielding layer 3 is covered on the surface of a flat substrate film 2. This light-shielding layer 3 contains a matting agent 31 and a matrix portion 32. Undulations are formed on the surface of the light-shielding layer 3 by the matting agent 31. Here, the Ra of the surface of the light-shielding component 1 can be controlled by adjusting the particle size, particle size distribution, content of the matting agent 31, and the film thickness of the light-shielding layer 3. Furthermore, it can also be controlled by adjusting the type of solvent used in preparing the coating solution, the concentration of the solid component, and the amount applied to the substrate film. Further, it can also be controlled by the coating manufacturing conditions, such as the coating method of the coating solution, the drying temperature, the drying time, and the airflow during drying.

[0044] In method (B), such as Figure 2 As shown in (a), an uneven surface is formed on the surface of the substrate film 2. When the substrate film is a resin film, a sandblasting method can be used, for example, to form the uneven surface. Here, Ra can be controlled by controlling the particle size of the abrasive used, the blasting pressure, etc. Alternatively, for example, a matting agent can be included in the raw material of the substrate film to prepare a substrate film containing a matting agent. As the matting agent, it is preferable to use a matting agent of the same type as the matting agent in the light-shielding layer, which will be described later. The Ra of the substrate film surface is controlled by controlling the particle size, particle size distribution, content of the matting agent, and the thickness of the substrate film.

[0045] Furthermore, a coating liquid or the like can be applied to the uneven substrate film 2, and a resin film 4 with a similar uneven shape to the surface of the substrate film 2 can be formed on the surface of the light-shielding member 1. Here, the resin film 4 on the surface of the light-shielding member includes resin components such as acrylic resin, polyester resin, epoxy resin, polyurethane resin, urea-formaldehyde resin, melamine resin, fluoropolymer resin, and imide resin. The resin film 4 can be made free of matting agents, and the Ra and other properties of the surface of the light-shielding member 1 can be controlled by controlling the uneven shape of the resin substrate film 2 and the film thickness of the resin film 4.

[0046] Furthermore, the materials and film thicknesses differ between the resin film 4 described above and the blackening layer described later. Specifically, the resin film 4 is formed from resin components, and its film thickness is approximately 1–50 μm, preferably approximately 2–10 μm. On the other hand, the blackening layer described later is formed from inorganic materials or submicron-sized resin particles and binder resin components, and its film thickness is approximately 10 nm–200 nm.

[0047] Through the above distinctions, a blackness of L value of 12 or less is achieved in the black light-shielding component of the present invention, which has a blackening layer.

[0048] In method (C), as in method (B), an uneven surface is formed on the surface of the substrate film, and as in method (A), a light-shielding layer containing a matting agent is covered on the surface of the light-shielding component. In this structure, the Ra of the surface of the light-shielding component can be controlled by the uneven shape of the surface of the substrate film 2, the film thickness of the light-shielding layer, the particle size, particle size distribution, content of the matting agent in the light-shielding layer, and manufacturing conditions such as the light-shielding layer.

[0049] Preferably, the black light-shielding component of the present invention has a structure in which a light-shielding layer is formed on at least one side of the substrate film. Furthermore, in the following description, the light-shielding layer also includes a resin film without a matting agent, formed by method (B), having an uneven shape (roughened portion) formed on the surface of the substrate film, and covering its surface.

[0050] The specific material composition of the black light-shielding component of the present invention will now be described.

[0051] (1) Substrate film

[0052] There are no particular limitations on the substrate film used in this invention; it can be either transparent or opaque. Furthermore, the substrate film of this invention can be made of resin or metal.

[0053] Examples of resin-based films include polyethylene, polypropylene, ethylene-propylene copolymer, copolymers of ethylene with α-olefins having 4 or more carbon atoms, polyesters such as polyethylene terephthalate, polyamides such as nylon, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinyl acetate and other general-purpose plastic films, polycarbonate, polyimide and other engineering plastic films.

[0054] In addition, as a metal substrate film, examples include metal sheets using metals such as gold, silver, copper, aluminum, titanium, zinc, beryllium, nickel, and tin, and alloy sheets using alloys such as phosphor bronze, copper-nickel, copper-beryllium, stainless steel, brass, and duralumin.

[0055] Among these materials, from the viewpoints of high strength, economy, and versatility, biaxially stretched polyethylene terephthalate is preferred; from the viewpoint of heat resistance, polyimide film is preferred; and from the viewpoint of high heat resistance, copper-based metal sheets are preferred. When the substrate film is a resin-based substrate film, by pre-kneading these materials with a black dye such as carbon black or aniline black to obtain a high-light-blocking material with an optical concentration of 2 or higher, preferably 4 or higher, a superior light-blocking effect can be obtained.

[0056] There is no particular limitation on the thickness of the substrate film. When using a resin-based substrate film, a thickness of 4 to 250 μm is preferred, and 12 to 100 μm is more preferred. By setting the thickness within the above range, it can also be applied to small, thin optical components. Furthermore, in the case of optical devices such as camera units for mobile phones, a thickness of 4 to 20 μm is preferred.

[0057] When using a metal substrate film, the thickness is preferably 6 to 40 μm, and especially in optical devices such as camera units for mobile phones, the thickness is preferably 10 to 20 μm.

[0058] When using methods (B) and (C) described above, a matte finish is applied to the surface of the substrate film to form an uneven surface (roughened area). There are no particular limitations on the matte finishing method; known methods can be used. For example, when the substrate film is a resin-based substrate film, chemical etching, spraying, calendering, rolling, corona discharge, plasma discharge, or chemical matte finishing methods using resin and a roughening agent can be used. Alternatively, the substrate film can directly contain a matte agent to form an uneven surface on the resin-based substrate film. From the viewpoints of ease of shape control, economy, and operability, spraying is preferred among the above processing methods, and sandblasting is particularly preferred.

[0059] In sandblasting, the surface properties such as Ra can be controlled by adjusting the particle size of the abrasive and the blasting pressure. Similarly, in calendering, the surface properties such as Ra can be controlled by adjusting the shape and pressure of the calendering roller.

[0060] On the other hand, when the substrate film is a metal substrate film, unevenness can be formed on the surface through blackening treatment, spraying treatment, etching treatment, etc. In addition, when the substrate film is a metal substrate film, at least one of a light-shielding layer containing a matting agent or a light-shielding layer without a matting agent, which will be described later, needs to be formed on the unevenness (roughened portion) of the surface.

[0061] (2) Fixing layer

[0062] To improve the adhesion between the substrate film and the light-shielding layer, a fixing layer can be provided before the light-shielding layer is applied to at least one side of the substrate film. As the fixing layer, urea-formaldehyde resin, melamine resin, polyurethane resin, polyester resin, etc., can be used. For example, a polyurethane resin layer can be obtained by coating the substrate film surface with a solution containing polyisocyanate and active hydrogen compounds such as diamine or glycol, and then curing it. Furthermore, when the fixing layer is urea-formaldehyde resin or melamine resin, it can be obtained by coating the substrate surface with a solution containing water-soluble urea-formaldehyde resin or water-soluble melamine resin, and then curing it. Polyester resin can be obtained by coating the substrate surface with a solution dissolved or diluted in an organic solvent (methyl ethyl ketone, toluene, etc.) and then drying it.

[0063] (3) Light-shielding layer

[0064] As described above, in method (B), except for the light-shielding member that only sets the unevenness formed on the surface of the resin substrate film as a light-shielding layer, a light-shielding layer is covered on at least one side of the substrate film. As the light-shielding layer, there are light-shielding layers containing a matting agent used in methods (A) and (C) and light-shielding layers (high-hardness layers, thin films) that do not contain a matting agent used in method (B).

[0065] The structure of each light-shielding layer will be explained below.

[0066] i) A light-blocking layer containing a matting agent

[0067] The components of the light-shielding layer include resin components, matting agents, and dyeing / conductive agents.

[0068] The resin component serves as a binder for matting agents and dyeing / conductive agents. There are no particular limitations on the material of the resin component; either thermoplastic resins or thermosetting resins can be used. Specific examples of thermosetting resins include acrylic resins, polyurethane resins, phenolic resins, melamine resins, urea-formaldehyde resins, allyl phthalate resins, unsaturated polyester resins, epoxy resins, and alkyd resins. Furthermore, examples of thermoplastic resins include polyacrylate resins, polyvinyl chloride resins, butyral resins, and styrene-butadiene copolymer resins. From the viewpoints of heat resistance, moisture resistance, solvent resistance, and surface hardness, thermosetting resins are preferred. Among thermosetting resins, acrylic resins are particularly preferred considering flexibility and the toughness of the coating.

[0069] By adding a curing agent as a component of the light-shielding layer, cross-linking of the resin components can be promoted. As a curing agent, urea compounds, melamine compounds, isocyanate compounds, epoxy compounds, aziridine compounds, oxazoline compounds, etc., with functional groups can be used. Among these, isocyanate compounds are particularly preferred. The preferred proportion of the curing agent relative to 100% by weight of the resin component is 10-50% by weight. By adding a curing agent within the above range, a light-shielding layer with more suitable hardness can be obtained, maintaining the Ra of the light-shielding layer for a long time, even when sliding between it and other components, thus maintaining excellent anti-reflective properties.

[0070] When using a curing agent, a reaction catalyst may also be used simultaneously to promote the reaction. Examples of reaction catalysts include ammonia and ammonium chloride. The preferred ratio of reaction catalyst to 100% by weight of curing agent is 0.1% to 10% by weight.

[0071] As matting agents, both resin-based and inorganic particles can be used. Examples of resin-based particles include melamine resin, benzomelamine resin, benzomelamine / melamine / formalin condensate, acrylic resin, polyurethane resin, styrene resin, fluoropolymer, and silicone resin. Examples of inorganic particles include silica, alumina, calcium carbonate, barium sulfate, and titanium dioxide. These can be used alone or in combination of two or more.

[0072] The average particle size, particle size distribution, and content of the matting agent vary depending on the thickness of the light-shielding layer and the degree of unevenness on the surface of the substrate film, and are adjusted to obtain the Ra and other parameters required for the surface of the light-shielding component. In method (A), for example, when a light-shielding layer with a thickness of 2 to 35 μm is formed on a smooth substrate film, the average particle size of the matting agent is typically preferred to be 1 to 40 μm. Furthermore, when the thickness of the light-shielding layer is set to 4 to 25 μm, the average particle size of the matting agent is preferably 5 to 20 μm.

[0073] In method (C), for example, when a light-shielding layer with a thickness of 1 to 35 μm is formed on a substrate film having an uneven shape, the average particle size of the matting agent is preferably 2 to 15 μm. Furthermore, when the thickness of the light-shielding layer is set to 2 to 7 μm, the average particle size of the matting agent is preferably 2 to 10 μm.

[0074] The particle size distribution of the matting agent varies depending on the combination of the film thickness of the light-shielding layer and the size of the selected matting agent, and cannot be generalized, but it is preferable to have the sharpest possible particle size. Furthermore, multiple matting agents with different average particle sizes and particle sizes can be used to adjust Ra, etc.

[0075] The amount of matting agent added varies depending on the average particle size, particle size distribution, and film thickness of the matting agent, but in the case of method (A), it is preferably 20% to 80% by weight relative to 100% of the total amount of the matting layer. Furthermore, in the case of method (C), it is preferably 1% to 40% by weight.

[0076] By controlling the surface shape of the resin-based substrate film, as well as the average particle size, particle size distribution, and content of the matting agent, and further controlling the film thickness of the light-shielding layer, the Ra of the light-shielding layer surface is adjusted, thereby achieving excellent light-shielding properties even when the film is thin.

[0077] There are no particular limitations on the shape of the matting agent, but considering the flow characteristics, coatability, and sliding properties of the resulting opaque layer, spherical matting agents are preferred. Furthermore, to suppress light reflection, the matting agent can be dyed black using organic or inorganic dyes. Specific dyes include carbon black, aniline black, and carbon nanotubes. By using a matting agent dyed with carbon black, and further adding carbon black or similar dyeing / conductive agents to the opaque layer, superior opaque properties can be obtained.

[0078] Carbon black and similar materials are commonly used as dyeing / conductive agents. By adding these agents, the light-shielding layer is dyed, thus improving the anti-reflective effect and achieving good antistatic properties.

[0079] The average particle size of the dyeing / conductive agent is preferably 1 nm to 1000 nm, more preferably 5 nm to 500 nm. By setting the particle size of the dyeing / conductive agent within the above range, superior light-shielding properties can be obtained.

[0080] Furthermore, relative to 100% by weight of the total light-shielding layer, the content of the dye / conductive agent is preferably 9% to 38% by weight. By setting the content of the dye / conductive agent within the above range, superior light-shielding properties can be obtained.

[0081] In this invention, as components of the light-shielding layer, leveling agents, thickeners, pH adjusters, lubricants, dispersants, defoamers, etc., can be further added as needed.

[0082] In addition to polytetrafluoroethylene (PTFE) particles, which are solid lubricants, polyethylene wax, organosilicon particles, etc., can be used as lubricants.

[0083] A uniform coating solution is prepared by adding the above-mentioned constituent components to an organic solvent or water and mixing them. Examples of organic solvents that can be used include methyl ethyl ketone, toluene, propylene glycol monomethyl ether acetate, ethyl acetate, butyl acetate, methanol, ethanol, isopropanol, butanol, etc.

[0084] A light-shielding layer is formed by directly applying the obtained coating liquid to the surface of the substrate film or a pre-formed fixing layer and then drying it. There are no particular limitations on the coating method; roller coating, doctor blade coating, etc., can be used.

[0085] The thickness of the light-shielding layer in this invention is preferably 1 μm to 35 μm. Especially when a matting agent is contained, in method (A), the thickness of the light-shielding layer is preferably 2 μm to 30 μm, more preferably 4 μm to 25 μm. Furthermore, in method (C), the thickness of the light-shielding layer is preferably 1 μm to 10 μm, more preferably 2 μm to 7 μm.

[0086] By setting the thickness of the light-shielding layer within the aforementioned range, the desired anti-reflective effect and slip resistance can be obtained. Furthermore, the thickness of the light-shielding layer containing the matting agent is the height from the surface of the film substrate to the matrix portion where the matting agent does not protrude. The thickness of the aforementioned light-shielding layer can be measured based on JIS K7130.

[0087] ii) A light-blocking layer without matting agents

[0088] Next, the light-shielding layer without matting agent used in method (B) will be described. As mentioned above, in this structure, the light-shielding characteristics of the light-shielding component can be controlled according to the uneven shape of the substrate film. Therefore, it is necessary to make the light-shielding layer covering the surface of the substrate film thin to maintain the uneven shape of the substrate film surface. In such a structure, the light-shielding layer functions as a conductive layer and a sliding layer.

[0089] The components of the aforementioned light-shielding layer include resin components and dyeing / conductive agents.

[0090] The resin component can be the same material used in the light-blocking layer containing the matting agent.

[0091] The dyeing / conductive agent can be the same material used in the light-shielding layer containing the matting agent.

[0092] In the light-shielding layer of this structure, leveling agents, thickeners, pH adjusters, dispersants, defoamers, etc., can also be added as needed.

[0093] A uniform coating solution is prepared by adding the above-mentioned constituent components to water, alcohol, or organic solvent and mixing and stirring.

[0094] The obtained coating liquid is applied directly to the surface of a substrate film that has undergone a pre-matte finish to form an uneven shape, or it is applied through a pre-formed fixing layer and dried to form a light-blocking layer. There are no particular limitations on the coating method; roller coating, doctor blade coating, etc., can be used.

[0095] As in this structure, without the presence of a matting agent, the thickness of the light-shielding layer is preferably 1 μm to 15 μm, more preferably 2 μm to 10 μm. By setting the thickness of the light-shielding layer within the above range, conductivity, slip properties, etc., can be imparted without suppressing the unevenness of the substrate film. Furthermore, the thickness of the light-shielding layer without the presence of a matting agent is the thickness of the light-shielding layer itself after eliminating the undulations on the surface of the film substrate.

[0096] (4) Blackening layer

[0097] The black light-shielding component of the present invention is characterized in that a blackening layer is formed on the uneven surface of the resin light-shielding layer described in (3).

[0098] Figure 1 (b) and Figure 2 (b) A cross-sectional schematic diagram of the black light-shielding component 10 of the present invention having a blackened layer 5 is shown. It is believed that the blackened layer 5 of the black light-shielding component 10 of the present invention is thin and has a structure in which micro-layers (microparticles) are unevenly present on the resin-based light-shielding layer 3. Furthermore, based on the diffuse reflection of (black) light generated on the surface of the blackened layer with such a structure, it is inferred that the black light-shielding component of the present invention has excellent anti-reflective effect and blackness based on low gloss.

[0099] That is, the present invention is based on the following discovery: by forming a thin blackening layer on a resin-based light-shielding layer with an uneven shape, and adjusting the surface to achieve an arithmetic mean roughness Ra of 0.25 μm or more, excellent anti-reflective effect based on low gloss and a blackness with an L value of 12 or less can be achieved. The maximum thickness of the blackening layer is not particularly limited as long as it is less than Ra, preferably 10 nm to 200 nm, more preferably 50 to 150 nm, and further preferably 70 to 110 nm.

[0100] In addition, the maximum thickness of the blackening layer can be calculated based on microscopic observation photographs, etc.

[0101] For the blackening layer, if the above conditions are met, it can be an inorganic material, an organic material, a mixture of organic and inorganic materials, or a composite material. Examples of inorganic materials include metals such as gold, silver, copper, platinum, cobalt, tin, zinc, lead, palladium, ruthenium, neodymium, samarium, aluminum, magnesium, indium, gallium, bismuth, and their alloys; alumina, silicon dioxide (silicon dioxide, etc.), titanium oxide (titanium monoxide, titanium pentoxide, titanium dioxide, etc.), indium tin oxide (ITO), cerium oxide, zinc oxide, chromium oxide (Cr2O3, etc.), gallium oxide, hafnium oxide, nickel oxide, magnesium oxide, niobium oxide (niobium pentoxide, etc.), tantalum oxide (… Metal oxides such as tantalum pentoxide, yttrium oxide, and zirconium oxide, and their complexes; fluorides such as magnesium fluoride, aluminum fluoride, calcium fluoride, cerium fluoride, lanthanum fluoride, lithium fluoride, sodium fluoride, neodymium fluoride, samarium fluoride, ytterbium fluoride, and yttrium fluoride; nitrides such as titanium nitride, chromium nitride, titanium carbonitride, titanium aluminum nitride, boron nitride, aluminum nitride, carbon nitride, and boron carbonitride; and carbides such as carbon (amorphous carbon, diamond, diamond-like carbon, graphite, etc.), titanium carbide, silicon carbide, boron carbide, and tungsten carbide.

[0102] Furthermore, examples of organic materials include submicron particles such as acrylic resins, styrene resins, silicone resins, and fluoropolymers. Additionally, organic-inorganic hybrid materials (organic-inorganic nanocomposites) composed of the aforementioned metal oxides and organic molecules can also be used.

[0103] There are no particular limitations on the method for forming the blackening layer. Dry methods such as sputtering, vacuum evaporation, ion plating, and chemical vapor deposition (CVD) can be used, as well as wet methods such as coating using the sol-gel method and coating by dispersing / mixing the aforementioned blackening layer material in a dispersion of sol solution, solvent, and binder components.

[0104] Among these methods, the dry method is preferred for achieving superior blackening effects. It is believed that during the dry blackening layer formation process, nanoscale particles adhere to the convex, concave, and sloping surfaces of the light-shielding layer, creating a more complex and uneven surface. It is speculated that in light-shielding components with such surface shapes, incident light is both reflected and absorbed in a complex manner on the surface of the blackening layer, thus achieving superior anti-reflective effects and blackness based on low gloss.

[0105] Furthermore, from the viewpoint that, unlike wet methods, there is no reduction in surface roughness caused by coating liquid accumulating in the recesses, the dry method is also preferred. Moreover, from the viewpoint that it does not use solvents and therefore has less adverse environmental impact, and requires less equipment, the dry method is also preferred.

[0106] Among dry processes, sputtering is the preferred method due to its superior adhesion to the light-shielding layer, scratch resistance, and ease of thickness adjustment.

[0107] On the other hand, from a cost-effectiveness perspective, the wet process is preferred due to its superior economic efficiency, workability, and yield. It is speculated that in the wet process, the sol solution or dispersion is applied to the uneven surfaces, protrusions, depressions, and slopes of the light-shielding layer. During drying, the solvent evaporation generates upward convection, resulting in a more complex and uneven surface texture on the light-shielding layer. It is speculated that in a light-shielding component with such a surface shape, incident light is both reflected and absorbed on the blackened layer surface, thus achieving superior anti-reflective effects and blackness based on low gloss.

[0108] The material, formation method, and thickness of the blackening layer can be appropriately set considering the required characteristics and cost of the light-shielding component.

[0109] [Example]

[0110] The present invention will be further described in detail through the following embodiments, but the present invention is not limited to these embodiments. In addition, unless otherwise specified, in the embodiments, "%" and "parts" represent weight % and weight parts, respectively.

[0111] <Structure of the black light-shielding component>

[0112] (1) Substrate film

[0113] (1-1) Polyimide film: KAPTON 50MBC (12μm thick), manufactured by Toray DuPont Co., Ltd.

[0114] (1-2) Copper foil film: NC-WS (12μm thickness), manufactured by Furukawa Electric Co., Ltd.

[0115] (1-3) Polyethylene terephthalate film: The Lumirror X30 (thickness 50μm, manufactured by Toray Industries, Inc.) was sandblasted on both sides to form an uneven film on the surface.

[0116] (2) Light-shielding layer

[0117] (a) Resin

[0118] (a1) Acrylic resin: Acrydic A814, manufactured by DIC Corporation.

[0119] (b) Curing agent

[0120] (b1) TDI polyisocyanate: Coronate L, manufactured by Tosoh Corporation

[0121] (c) Dyeing / Conductive Agent

[0122] (c1) Carbon black; NX-592 black, manufactured by Daihatsu Seika Co., Ltd.

[0123] (d) Matting agent

[0124] (d1) Acrylic filler: MX-200 (average particle size: 2μm), manufactured by Soken Chemical Co., Ltd.

[0125] (d2) Acrylic filler: MX-300 (average particle size: 3μm), manufactured by Soken Chemical Co., Ltd.

[0126] (d3) Acrylic filler: MX-500 (average particle size: 5μm), manufactured by Soken Chemical Co., Ltd.

[0127] (3) Blackening layer

[0128] (3-1) Formation based on sputtering method

[0129] A magnesium fluoride layer was formed by sputtering in argon gas using a sputtering apparatus (model: CFS-4ES) manufactured by Shibaura Electric Co., Ltd., with magnesium fluoride (MgF2) as the target. The final pressure was 3 × 10⁻⁶. -3 Pa, sputtering pressure is 7.6 × 10 -3 Pa, Ar flow rate 11 sccm. Additionally, a magnesium fluoride layer was pre-formed on a flat substrate under specified conditions (200 W), and the relationship between sputtering time and layer thickness was determined. Magnesium fluoride sputtered films formed under conditions of 80 nm, 100 nm, and 120 nm thickness were designated as thin film, medium film, and thick film, respectively.

[0130] (3-2) Formation based on dispersion coating

[0131] (3-2-1) Adhesive component: Polyester resin

[0132] A coating solution was prepared by mixing 1 part of magnesium fluoride particle dispersion (9076MF, primary particle size 39 nm, solid content 26%: manufactured by Tokushiki Co., Ltd.), 2 parts of resin solution dissolved in methyl ethyl ketone to achieve a polyester resin concentration of 10% by weight (Bylon 200: manufactured by Toyobo Co., Ltd.), and 87 parts of methyl ethyl ketone. The obtained coating solution was applied by rod coating and heated to dry, forming a blackened layer with a thickness of approximately 100 nm.

[0133] (3-2-2) Binder component: Silica

[0134] A coating solution was prepared by mixing 1 part of the magnesium fluoride particle dispersion used in (3-2-1), 10 parts of a solution obtained by diluting silica sol (Colcoat N-103X (2% solids), manufactured by Colcoat Co., Ltd.) to 20% with n-butanol, and 90 parts of dipropylene glycol monomethyl ether. The obtained coating solution was applied by rod coating and heated to dry, forming a blackened layer with a thickness of approximately 100 nm.

[0135] (3-3) Formation based on sol-gel method

[0136] A coating solution was prepared by mixing 25 parts of silica sol (Colcoat N-103X (2% solids), manufactured by Colcoat Co., Ltd.) and 75 parts of a solvent with a water:isopropanol weight ratio of 1:2. The obtained coating solution was applied by rod coating and heated to dry, forming a blackened layer with a thickness of approximately 100 nm.

[0137] (Examples 1-12, Comparative Examples 1-9)

[0138] The components of the light-shielding layer (2) above were added to the solvent according to the mixing ratios (by weight) shown in Tables 1 to 3, and the mixture was stirred to obtain the coating solution. Here, methyl ethyl ketone and toluene were used as solvents.

[0139] Using the substrate films shown in Tables 1-3, a coating liquid containing the components shown in Tables 1-3 is applied to one side, and then dried at 100°C for 2 minutes to form a light-shielding layer.

[0140] On the obtained light-shielding layer, a blackening layer as shown in Tables 1-3 was formed by the method described in (3) above. The measurement results of the average film thickness of the light-shielding layer, the average film thickness of the blackening layer, the Ra of the light-shielding component, the gloss with respect to incident light at an incident angle of 60°, and the L value are shown in Tables 1-3. The arithmetic mean roughness Ra of the light-shielding component was calculated based on JIS B0601:2001, and the L value was calculated based on JIS Z8781-4. In addition, for the measurement of gloss with respect to incident light at an incident angle of 60°, the specular gloss with respect to an incident angle of 60° was measured according to JIS Z8741.

[0141] Furthermore, the average film thickness of the light-shielding layer was measured based on JIS K7130. The thickness of the light-shielding layer containing the matting agent was defined as the height from the surface of the film substrate to the matrix portion where the matting agent does not protrude. On the other hand, the thickness of the light-shielding layer without the matting agent was defined as the thickness of the light-shielding layer itself after eliminating the undulations on the surface of the film substrate.

[0142] The average film thickness of the magnesium fluoride blackening layer based on sputtering described in the table is not an actual measurement value, but rather the average film thickness when the magnesium fluoride layer is formed on a flat substrate by sputtering under the same conditions as when it is formed on a light-shielding layer. Furthermore, the average film thickness of the blackening layers based on dispersion coating and sol-gel methods described in Table 3 are also not actual measurements, but rather the average film thickness when the respective blackening layers are formed on a flat substrate by dispersion coating and sol-gel methods under the same conditions as when it is formed on a light-shielding layer.

[0143] As shown in Table 1, in Reference Example 1, which is a flat polyimide film, the Ra value is low at 0.2 μm, the gloss at a 60° incident angle is 35.4%, and the L value is 28.3. Both the anti-reflective effect and blackness are low due to the low gloss. In contrast, in Comparative Example 1, which has a light-shielding layer containing a matting agent, the Ra value increases to 0.48 μm, the surface is roughened, and both the anti-reflective effect and blackness are improved due to the low gloss, but the blackness is insufficient.

[0144] On the other hand, it was confirmed that in Examples 1 to 3, where a blackening layer, consisting of a sputtered magnesium fluoride film, was further provided on the light-shielding layer, the gloss and L-value at a 60° incident angle were significantly reduced, resulting in excellent anti-reflective effects and blackness based on low gloss. In particular, compared to the black light-shielding component of Comparative Example 1 without a blackening layer, the Ra values ​​of the black light-shielding components of Examples 1 and 2, which had intermediate and thin blackening layers, increased significantly from 0.48 μm to 1.28 μm and 1.32 μm, respectively. Furthermore, the Ra value of the black light-shielding component of Example 3, which had a thick blackening layer, was 0.49 μm, showing a lower rate of increase in Ra compared to Examples 1 and 2. Therefore, by setting the thickness of the blackening layer within an appropriate range without making it excessively thick, the surface irregularities of the black light-shielding component can be made more complex, resulting in a light-shielding component with excellent anti-reflective effects based on low gloss and higher blackness.

[0145] Furthermore, it can be seen that, compared to Reference Example 1, in Reference Example 2, where a blackening layer with an intermediate film was formed on a flat polyimide film, the gloss and L value at a 60° incident angle remained almost unchanged. This confirms the effectiveness of the present invention in forming a blackening layer on the surface of a light-shielding layer with an uneven shape.

[0146] [Table 1]

[0147]

[0148] Table 2 shows the comparison results of Ra, gloss at a 60° incident angle, and L value of the surface of the light-shielding component when a blackened layer with an intermediate film was formed on the surface of a light-shielding layer with a modified surface roughness using matting agents of different particle sizes. As shown in Comparative Examples 1, 4, and 5, it can be seen that by changing the particle size of the matting agent added to the light-shielding layer, the Ra of the surface changes, but the L value in all comparative examples exceeds 20, and sufficient blackness cannot be obtained. In contrast, it was confirmed that in Examples 1, 4, and 5, where a blackened layer of magnesium fluoride with an intermediate film was formed by sputtering, the gloss and L value at a 60° incident angle were significantly reduced, exhibiting excellent anti-reflective effect based on low gloss and high blackness.

[0149] [Table 2]

[0150]

[0151] Table 3 shows the evaluation results of Example 6, a sample in which a light-shielding layer and a blackening layer were formed in the same manner as in Example 1, except that a copper foil film was used as the substrate film. Compared with Comparative Example 6, which did not form a blackening layer, in Example 6, Ra increased, and the gloss at a 60° incident angle and L value were significantly reduced. This confirms that the effects of the present invention can be obtained even when a metal substrate film is used as the substrate film.

[0152] [Table 3]

[0153]

[0154] Furthermore, the same evaluation was conducted on Example 7, which used a polyethylene terephthalate film as the substrate and formed a blackening layer directly on the blasted surface; Example 8, which formed a blackening layer after forming a light-shielding layer containing a matting agent on the blasted surface; and Example 9, which formed a blackening layer after forming a light-shielding layer without a matting agent on the blasted surface. Compared to Comparative Examples 7, 8, and 9, which did not form a blackening layer, the Ra of the light-shielding components in these examples increased, while the gloss and L value at a 60° incident angle decreased significantly. Therefore, it can be seen that the effects of the present invention can be obtained regardless of the method of forming the light-shielding layer.

[0155] In Example 10, a black light-shielding component was prepared and evaluated in the same manner as in Example 1, except that a sputtered layer was used instead of a blackening layer and the magnesium fluoride / polyester resin layer was formed by a dispersion coating method. Compared with Comparative Example 1, the Ra value of Example 10 increased, the gloss at a 60° incident angle decreased, and the L value decreased significantly. This confirms that the effects of the present invention can also be obtained by a blackening layer formed by a wet process.

[0156] Furthermore, in Example 11, a black light-shielding component was prepared in the same manner as in Example 1, except that a sputtered layer was used instead of a blackening layer and it was set as a magnesium fluoride / silicon oxide layer. In Example 12, a black light-shielding component was prepared in the same manner as in Example 1, except that the sputtered layer was set as a silicon oxide layer. Compared with Comparative Example 1, the Ra values ​​of Examples 11 and 12 were both increased, the gloss at a 60° incident angle was decreased, and the L value was significantly reduced. This confirms that the effects of the present invention can be obtained by forming a thin and uneven blackening layer on a resin-based light-shielding layer, regardless of the method or material used to form the blackening layer.

Claims

1. A black light-shielding component comprising: a substrate film, a resin-based light-shielding layer having an uneven shape formed on at least one surface of the substrate film, and a blackening layer formed on the resin-based light-shielding layer, characterized in that, The surface arithmetic mean roughness Ra of the resin-based light-shielding layer and the surface where the blackening layer is formed is 0.25 μm or more, and the L value is 12 or less, wherein the L value is calculated based on JIS Z8781-4. Brightness in color space The value, wherein the maximum thickness of the blackened layer is less than Ra, The blackening layer contains at least one selected from magnesium fluoride, calcium fluoride, lithium fluoride, aluminum oxide, gallium oxide, and silicon oxide.

2. The black light-shielding component according to claim 1, characterized in that, The resin-based light-shielding layer has a resin layer containing a matting agent and resin components.

3. The black light-shielding component according to claim 1 or 2, characterized in that, The resin-based light-shielding layer includes a roughened portion formed on the surface of the substrate film.

4. The black light-shielding component according to claim 1 or 2, characterized in that, The blackening layer is formed by any one of sputtering, vapor deposition, ion plating, or chemical vapor deposition (CVD).

5. The black light-shielding component according to claim 1 or 2, characterized in that, The maximum thickness of the blackening layer is less than 1 / 2 of the arithmetic mean roughness Ra of the surface.

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