Optical components

Abstract

Provided is an optical member including a transparent resin substrate, a hard coat layer, an antireflection film, and a protection film in this order, wherein the antireflection film comprises, in order from the hard coat layer side, an intermediate refractive index layer having a refractive index of 1.51-1.60 and a layer thickness of 60-100 nm, a high refractive index layer having a refractive index of 1.65-1.80 and a layer thickness of 150-190 nm, and a low refractive index layer having a refractive index of 1.33-1.40 and a layer thickness of 70-90 nm, the protection layer has a refractive index of 1.49-1.50 and a layer thickness of 10-25 nm, the intermediate refractive index layer comprises a cured product of a composition containing an alkoxysilane compound or the like and an organic-inorganic composite compound as binder components, the luminous mean reflectance of both surfaces at wavelengths of 380-780 nm is 0.8% or less, the mean reflectance of both surfaces at wavelengths of 445-455 nm is 1.0% or less, the mean reflectance of both surfaces at wavelengths of 515-525 nm is 1.0% or less, the mean reflectance of both surfaces at wavelengths of 800-870 nm is 3.0% or less, all of the haze value at wavelengths of 445-455 nm, the haze value at wavelengths of 515-525 nm, and the haze value at wavelengths of 865-875 nm are 0.4% or less. The optical member has excellent antireflection property and transmission property for laser light.

Description

[Technical Field]

[0001] This invention relates to an optical component that exhibits excellent anti-reflection and transmittance properties to laser light. [Background technology]

[0002] Patent Document 1 proposes an anti-reflective film consisting of three layers formed by coating on a translucent substrate, with each layer having a predetermined thickness. However, the minimum reflectance of this anti-reflective film is estimated to be around 0.5% at a wavelength of 600 nm, and the maximum reflectance for visible light between 380 and 780 nm is estimated to be several percent. Therefore, there is room for further improvement to satisfy the reflectance characteristics required for modern photo-display devices. The present inventors previously proposed an anti-reflective laminate having a double-sided luminous mean reflectance of 0.6% or less for visible light with wavelengths of 380 to 780 nm, using a multilayer anti-reflective film consisting of four different refractive index layers (Patent Document 2). Incidentally, in recent years, medical endoscopes and laparoscopes utilizing laser light have been used, contributing to the advancement of medicine. For example, a new device called a videoscope (electronic endoscope) has been developed for use in gastric and colon endoscopy. This videoscope is an endoscope that can clearly display images captured by an objective (light-receiving) lens and image sensor (CCD image sensor) built into the tip of the scope on a color monitor. At the tip, a window material is provided to protect these internal components from mechanical shock and bodily fluids. While this window material was conventionally made of glass, recently there has been a demand for disposable resin window materials from the perspective of preventing bacterial and viral infections. On the other hand, as an endoscopic light source, for example, a gastric endoscope uses a combination of two lasers with different wavelengths: a white light laser and a blue BLI (Blue-laser Imaging) laser. The bright white light produces sharp and vivid images, while the blue BLI light highlights the fine blood vessels on the mucosal surface, enabling accurate examination and diagnosis. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2002-182007 [Patent Document 2] WO2021-210371 [Overview of the project] [Problems that the invention aims to solve]

[0004] Conventional window materials, such as glass, are inherently poor in surface reflectivity, and therefore require anti-reflective coatings when used as windows. Similarly, resins also have poor surface reflectivity and light transmittance, necessitating anti-reflective coatings and other improvements for use as window materials. In particular, endoscope window materials that use laser light differ from ordinary visible light in characteristics because laser light is a monochromatic light with high directionality and a constant wavelength, requiring optical properties specific to laser light. It should be noted that the conventional optical components described in the aforementioned patent document all have optical properties that are specific to visible light with wavelengths of 380 to 780 nm, and are not components specifically designed for laser light. The inventors of the present invention conducted thorough research on optical components for laser light and found that their anti-reflective and transmittance properties depend on the refractive index of each refractive index layer, the balance of each refractive index, the thickness of the refractive index layers, and the chemical components constituting the refractive index layers. They discovered that the aforementioned problems could be solved by precisely controlling the refractive index and thickness of each refractive index layer and identifying the constituent components of the intermediate refractive index layer, leading to the present invention. The object of the present invention is to provide an optical component with excellent anti-reflection and transmission performance against laser light. [Means for solving the problem]

[0005] In other words, the present invention is an optical member comprising a transparent resin substrate, a hard coat layer, an anti-reflective film and a protective layer in this order, wherein the anti-reflective film is provided from the hard coat layer side, A medium refractive index layer with a refractive index of 1.51 to 1.60 and a layer thickness of 60 to 100 nm, A high refractive index layer with a refractive index of 1.65 to 1.80 and a layer thickness of 150 to 190 nm, A low refractive index layer with a refractive index of 1.33-1.40 and a layer thickness of 70-90 nm It is composed in the following order: The protective layer has a refractive index of 1.49 to 1.50 and a layer thickness of 10 to 25 nm. The aforementioned intermediate refractive index layer is made up of 100 parts by mass of at least one binder component selected from the group consisting of an alkoxysilane compound represented by the following formula (1) or its hydrolysate, an alkoxysilane compound represented by the following formula (2) or its hydrolysate, and an organic-inorganic composite compound.

[0006] [ka] (In the formula, R is an alkylene group, R 1 (where m is an alkyl group and m is 0 or 1.) [ka] (In the formula, R 1 R is an alkyl group. 2 (where n is an alkyl group, alkenyl group, or alkoxyalkyl group; n is 0, 1, or 2.) It consists of a cured product of a composition containing 30 to 100 parts by mass of metal oxide particles and 1 to 10 parts by mass of a metal chelate compound. The optical component is characterized in that the luminous mean reflectance of both sides at wavelengths of 380 to 780 nm is 0.8% or less, the average reflectance of both sides at wavelengths of 445 to 455 nm is 1.0% or less, the average reflectance of both sides at wavelengths of 515 to 525 nm is 1.0% or less, the average reflectance of both sides at wavelengths of 800 to 870 nm is 3.0% or less, and the haze value at wavelengths of 445 to 455 nm, 515 to 525 nm, and 865 to 875 nm are all 0.4% or less.

[0007] In the above invention of the optical component, 1) The binder component of the intermediate refractive index layer consists of at least two selected from the group consisting of the alkoxysilane compound represented by the formula (1) or its hydrolyzate, the alkoxysilane compound represented by the formula (2) or its hydrolyzate, and the organic-inorganic composite compound. 2) The binder component of the intermediate refractive index layer consists of 3-glycidoxypropyltrimethoxysilane and tetraethoxysilane. 3) The average particle size of the metal oxide particles is 1 to 30 nm. 4) The antireflection film has an intermediate low refractive index layer with a refractive index of 1.39 to 1.49 and a layer thickness of 115 to 175 nm on the hard coat layer side of the intermediate refractive index layer. The intermediate low refractive index layer is composed of a cured product of a composition containing 5 to 30 parts by mass of silica particles and 1 to 10 parts by mass of a metal chelate compound with respect to 100 parts by mass of at least one binder component selected from the group consisting of the alkoxysilane compound represented by the formula (1) or its hydrolyzate, the alkoxysilane compound represented by the formula (2) or its hydrolyzate, and the organic-inorganic composite compound. 5) The binder component of the intermediate low refractive index layer is the alkoxysilane compound represented by the formula (2) or its hydrolyzate, where 1 R is a methyl group or an ethyl group, 2 R is a methyl group or an ethyl group, and n is 0 or 1, and it is a mixture of different compounds selected from the group of compounds. 6) The average particle size of the silica particles is 1 to 10 nm. 7) The organic-inorganic composite compound is preferably a composite compound having a structure in which an alkoxysilyl group is bonded to a bisphenol A type epoxy compound, a novolak phenol compound, or a polyamic acid compound. is preferred.

Advantages of the Invention

[0008] The optical member of the present invention is excellent in antireflection properties and transparency with respect to laser light. Specifically, the visual average reflectance on both sides at a wavelength of 380 to 780 nm is 0.8% or less, the average reflectance on both sides at a wavelength of 445 to 455 nm is 1.0% or less, the average reflectance on both sides at a wavelength of 515 to 525 nm is 1.0% or less, the average reflectance on both sides at a wavelength of 800 to 870 nm is 3.0% or less, and the haze values at a wavelength of 445 to 455 nm, at a wavelength of 515 to 525 nm, and at a wavelength of 865 to 875 nm are all 0.4% or less. Since the reflectance and haze value are low and the transparency to laser light is excellent, the amount of transmitted laser light increases and a clear image can be obtained. Taking advantage of this optical property, the optical member of the present invention is suitable as a window material for endoscopes and laparoscopes using laser light.

Brief Description of the Drawings

[0009] [Figure 1] It is a reflectance distribution diagram of the optical member of Example 4. [Figure 2] It is a reflectance distribution diagram of the optical member of Comparative Example 16.

Modes for Carrying Out the Invention

[0010] <Configuration of the Optical Member> The optical member of the present invention is basically composed of a transparent resin substrate, a hard coat layer, an antireflection film, and a protective layer, which are laminated in this order. And the antireflection film, from the hard coat layer side, a medium refractive index layer having a refractive index of 1.51 to 1.60 and a layer thickness of 60 to 100 nm, a high refractive index layer having a refractive index of 1.65 to 1.80 and a layer thickness of 150 to 190 nm, a low refractive index layer having a refractive index of 1.33 to 1.40 and a layer thickness of 70 to 90 nm The layers are arranged in the order described above, and the protective layer has a refractive index of 1.49 to 1.50 and a layer thickness of 10 to 25 nm. Furthermore, the intermediate refractive index layer is composed of at least one binder component selected from the group consisting of an alkoxysilane compound represented by the following formula (1) or its hydrolysate, an alkoxysilane compound represented by the following formula (2) or its hydrolysate, and an organic-inorganic composite compound, in 100 parts by mass. [ka] (In the formula, R is an alkylene group, R 1 (where m is an alkyl group and m is 0 or 1.) [ka] (In the formula, R 1 R is an alkyl group. 2 (where n is an alkyl group, alkenyl group, or alkoxyalkyl group; n is 0, 1, or 2.) It consists of a cured product of a composition containing 30 to 100 parts by mass of metal oxide particles and 1 to 10 parts by mass of a metal chelate compound. The key features of this invention are the refractive index and thickness of the three refractive index layers constituting the anti-reflective coating, and by further identifying the constituent components of the medium- and low refractive index layers, excellent anti-reflective and transmission performance against laser light is achieved. The optical component of the present invention is preferable because, when the anti-reflective coating consists of four layers, with a medium-low refractive index layer located below the medium refractive index layer (on the hard coat layer side), it can improve the anti-reflective properties of laser light and increase transmittance. The medium-to-low refractive index layer has a refractive index of 1.39 to 1.49 and a layer thickness of 115 to 175 nm, and consists of a cured product of a composition containing 5 to 30 parts by mass of silica particles and 1 to 10 parts by mass of a metal chelate compound per 100 parts by mass of at least one binder component selected from the group consisting of an alkoxysilane compound represented by formula (1) or its hydrolysate, an alkoxysilane compound represented by formula (2) or its hydrolysate, and the organic-inorganic composite compound.

[0011] <Transparent resin base material> The substrate used in the present invention must be made of a transparent resin that has excellent impact strength and transparency. The total light transmittance of the transparent resin substrate is preferably 88% or more, more preferably 89% or more, and even more preferably 92% or more for light with a wavelength of 380 to 780 nm. Specific transparent resin substrates include those formed from at least one resin selected from the group consisting of acrylic resin, polycarbonate resin, polyethylene terephthalate resin, and triacetylcellulose resin, from the viewpoint of transparency and impact strength. This substrate may also be a laminated substrate formed by laminating the above resins. For example, a laminated transparent resin substrate of polycarbonate resin and polymethyl methacrylate resin may be used. The thickness of the transparent resin substrate is selected and designed appropriately based on the required transparency and impact strength, but is usually in the range of 0.2 to 2.0 mm. The upper limit of the thickness of the transparent resin substrate is preferably 1.0 mm or less, more preferably 0.8 mm or less, and particularly preferably in the range of 0.2 mm to 0.5 mm.

[0012] <Hard coat layer> The hard coat layer is preferably a layer containing a resin component that is cured using a trifunctional or less urethane (meth)acrylate and a tetrafunctional or more urethane (meth)acrylate as the main components. The thickness of the hard coat layer is preferably 1 to 3 μm. If this thickness is too thin, it becomes difficult to ensure the basic physical properties of the hard coat layer (e.g., hardness and strength). If it is excessively thick, the difference in physical properties between the hard coat and the substrate (e.g., flexibility and elongation) becomes large, which can easily lead to molding defects such as cracking. From this viewpoint, the thickness is preferably 1.2 to 2.5 μm, and more preferably 1.5 to 2 μm. The hard coat layer preferably contains a resin component formed by curing a trifunctional or less urethane (meth)acrylate and a tetrafunctional or more urethane (meth)acrylate as the main components, a silane coupling component, solid silica particles, and a metal chelate compound.

[0013] (Resin components) The resin component functions as a binder for forming a hard coat layer. It is preferable to use a combination of trifunctional or less urethane (meth)acrylate and tetrafunctional or more urethane (meth)acrylate as this binder. Specifically, trifunctional or less urethane (meth)acrylate forms a relatively flexible portion upon curing, while tetrafunctional or more urethane (meth)acrylate forms a hard portion upon curing. By using both in combination, a moderately dense and hard film can be formed. Furthermore, to reduce the viscosity of the binder and improve its applicability, it is preferable to use a conventional (meth)acrylate that does not have urethane bonds in its molecule in addition to the above-mentioned urethane (meth)acrylate. Urethane (meth)acrylate is obtained by reacting a terminal isocyanate compound, which is obtained by reacting a polyvalent isocyanate compound with a polyol compound having multiple hydroxyl groups, with a hydroxyl group-containing (meth)acrylate. The (meth)acryloyl groups in urethane (meth)acrylate are functional groups. For example, urethane (meth)acrylate with two (meth)acryloyl groups is difunctional, and one with three is trifunctional.

[0014] Therefore, a trifunctional or less urethane (meth)acrylate is one that has up to three (meth)acryloyl groups. For example, a urethane (meth)acrylate obtained by reacting a terminal isocyanate compound with pentaerythritol mono(meth)acrylate, resulting in one (meth)acryloyl group at each end, is used as a bifunctional urethane (meth)acrylate. Furthermore, when pentaerythritol mono(meth)acrylate and pentaerythritol di(meth)acrylate are reacted with a terminal isocyanate compound to introduce one (meth)acryloyl group to one end of the isocyanate compound and two (meth)acryloyl groups to the other end, the resulting product is used as a trifunctional urethane (meth)acrylate.

[0015] Furthermore, pentaerythritol di(meth)acrylate can be reacted with a terminal isocyanate compound to introduce two (meth)acryloyl groups to each end of the isocyanate compound, which is then used as a tetrafunctional urethane (meth)acrylate. The above example is just one example, and other urethane (meth)acrylates can also be used as long as they are trifunctional or less. For example, hydroxyl group-containing (meth)acrylic acid esters such as monoesters and diesters of (meth)acrylic acid with ethylene glycol, diethylene glycol, and polyhydric alcohols of trivalent or higher can be used, and a desired number of (meth)acryloyl groups can be introduced to obtain trifunctional or less urethane (meth)acrylates.

[0016] The same applies to tetrafunctional or more urethane (meth)acrylates. For example, by reacting pentaerythritol tri(meth)acrylate with isocyanates at both ends (e.g., trihexadiethylene diisocyanate), a hexafunctional urethane (meth)acrylate having three (meth)acryloyl groups at each end of the molecular chain can be obtained.

[0017] In the present invention, it is preferable that the mass ratio of the above-mentioned trifunctional or less urethane (meth)acrylate to the tetrafunctional or more urethane (meth)acrylate is 2 / 98 to 70 / 30, and particularly 10 / 90 to 60 / 40. If too much trifunctional or less urethane (meth)acrylate is used, the hardness of the resulting hard coat layer may be impaired, and the basic performance of the hard coat layer may be reduced. When using conventional (meth)acrylate, it is used in an amount of 0 to 50% by mass, based on the total amount of (meth)acrylate and urethane (meth)acrylate.

[0018] (Silane coupling component) The hard coat layer preferably contains a silane coupling component. The silane coupling component is used to stably disperse and retain the silica particles described later in this hard coat layer without them falling off, while also ensuring adhesion to the anti-reflective film.

[0019] As the silane coupling component, conventionally known silane coupling agents or their hydrolysates are used. Specific examples of silane coupling agents include vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and methyltrimethoxysilane.

[0020] In the present invention, the content ratio of the silane coupling component in the hard coat layer is preferably set to 1 to 30 parts by mass, more preferably to 5 to 20 parts by mass, per 100 parts by mass of the resin component formed from the aforementioned urethane (meth)acrylate, etc.

[0021] (Solid silica particles) The hard coat layer preferably contains solid silica particles that do not have internal cavities. The solid silica particles in the hard coat layer preferably have an average particle size of 5 to 500 nm and a refractive index in the range of 1.44 to 1.50. Using such particles allows for the uniform application of basic properties such as hardness throughout the entire hard coat layer. Hereinafter, the average particle size refers to the median diameter (d50).

[0022] The content of solid silica particles is preferably 10 to 80 parts by mass, and more preferably 20 to 60 parts by mass, per 100 parts by mass of the resin component formed from the aforementioned urethane (meth)acrylate, etc. By including them in the hard coat layer within this range, it is possible to maintain the basic properties of the hard coat layer while improving adhesion with the anti-reflective film and effectively preventing cracks and the like.

[0023] (Metal chelate compounds) The hard coat layer preferably contains a metal chelate compound. The metal chelate compound is used to introduce a cross-linked structure into the hard coat layer, making the hard coat layer denser. Although a cross-linked structure is formed by resin components such as the aforementioned urethane (meth)acrylate, the density is reduced by the use of low-functionality urethane (meth)acrylate to impart flexibility. Metal chelate compounds are used to compensate for the reduction in density without impairing the flexibility of the hard coat layer; in other words, they are used to adjust mechanical properties such as hardness that are affected by the density of the film. Furthermore, since these metal chelate compounds are also included in anti-reflective coatings, the use of metal chelate compounds can further improve the adhesion between the hard coat layer and the anti-reflective coating, effectively preventing cracks and other damage during molding.

[0024] Examples of such metal chelate compounds include titanium, zirconium, and aluminum compounds containing bidentate ligands. A bidentate ligand is a chelating agent that has two coordination sites, meaning it can coordinate to a metal with two atoms. Generally, it forms a 5- to 7-membered ring with O, N, and S atoms to form a chelate compound. Examples of these bidentate ligands include acetylacetonate, ethylacetoacetate, oxyacetophenonate, glycinato, ethanolamine, and mercaptoethylamine.

[0025] A suitable metal is aluminum, and specific examples of metal chelating compounds include aluminum chelating compounds such as diethoxy mono(acetylacetonate)aluminum, monoethoxy bis(acetylacetonate)aluminum, di-i-propoxy mono(acetylacetonate)aluminum, monoethoxy bis(ethylacetoacetate)aluminum, diethoxy mono(ethylacetoacetate)aluminum, and tris(acetylacetonate)aluminum.

[0026] The metal chelate compound described above is used in an amount of preferably 0.1 to 30 parts by mass, more preferably 0.5 to 15 parts by mass, per 100 parts by mass of the resin component formed from the urethane (meth)acrylate, etc. By using the metal chelate compound within this range, the hard coat layer can be made denser, improving mechanical properties such as hardness, and the adhesion between it and the anti-reflective film formed on the hard coat layer can be improved.

[0027] (Formation of the hard coat layer) The hard coat layer is formed by applying a hard coat layer forming solution containing monomers or oligomers for resin component formation onto a substrate to form a coating film, then drying as necessary, and subsequently carrying out a polymerization curing reaction. The above-mentioned hard coat layer forming solution is prepared by dissolving the above-mentioned components, along with optional components such as a catalytic amount of polymerization initiator, in the following organic solvent for the purpose of adjusting viscosity and ease of application. Polymerization initiators include chemically curable chemical polymerization initiators and photocurable photopolymerization initiators, and are used depending on the polymerization method in the curing process. Examples of chemical polymerization initiators include peroxides such as benzoyl peroxide, di-t-butyl peroxide, and methyl ethyl ketone peroxide. Examples of photopolymerization initiators include diketones such as benzyl and camphorquinone; benzoin or benzoin alkyl ethers such as benzoin, benzoin methyl ether, and benzoin ethyl ether; aromatic ketones such as benzophenone, benzoylbenzoic acid, and 1-hydroxycyclohexylphenyl ketone; benzyl ketals such as benzyldimethyl ketal and benzyl diethyl ketal; acetophenones such as acetophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one; and anthraquinones such as 2-methylanthraquinone and 2-ethylanthraquinone.

[0028] Suitable organic solvents for hard coat layer formation solutions include alcohol compounds such as methyl alcohol, ethyl alcohol, and propyl alcohol; aromatic compounds such as toluene and xylene; ester compounds such as ethyl acetate, butyl acetate, isobutyl acetate, and sec-butyl acetate; and ketone compounds such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and diacetone alcohol. Other solvents that can be used include methylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and cellosolve compounds such as methyl cellosolve, ethyl cellosolve, and propylene glycol monomethyl ether. The amount of organic solvent used should be such that the hard coat layer forming solution does not drip or otherwise become runny, and the viscosity is suitable for coating. Generally, the amount of organic solvent should be such that it accounts for 10 to 40% by mass of the total mass of the hard coat layer forming solution, so that the hard coat layer forming solution becomes transparent. Note that this amount of organic solvent includes the amount of dispersion medium such as solid silica particles. The above-mentioned components constituting the hard coat layer forming solution are usually mixed and stirred at around room temperature to form a solution. When commercially available particle dispersions are used, the solvent, which acts as the dispersion medium, will inevitably be mixed into the solution. The solvent in the hard coat layer forming solution, as well as any separately added organic solvents, are removed during the drying and curing process.

[0029] The method for applying the hard coat layer forming solution to the substrate is not particularly limited, and methods such as dip coating, roll coating, die coating, flow coating, and spraying can be used. However, the dip coating method is preferred from the viewpoint of appearance quality and layer thickness control. After application, the coating is dried, and then a hard coat layer is formed by a curing reaction caused by heating or irradiation with ionizing radiation such as ultraviolet light or electron beams. Drying is usually carried out at 40-90°C for 5-30 minutes. Curing is usually done at 60-90°C for 10-60 minutes when curing by heating, and at 200-1000 mJ when curing by ultraviolet light.

[0030] <Anti-reflective film> An anti-reflective coating is laminated on the aforementioned hard coat layer. This anti-reflective coating is a multilayer anti-reflective coating that is basically composed of three refractive index layers having the following characteristics. Low refractive index layer: refractive index of 1.33-1.40 and layer thickness of 70-90 nm High refractive index layer: refractive index of 1.65-1.80 and layer thickness of 150-190 nm Intermediate refractive index layer: refractive index of 1.51-1.60 and layer thickness of 60-100 nm The three refractive index layers described above are arranged in the following order from the hard coat layer side: the medium refractive index layer, the high refractive index layer, and the low refractive index layer. By using the above three layers of anti-reflective coating, the resulting optical component has a luminous mean reflectance (hereinafter also referred to as luminous mean reflectance) of 0.8% or less on both sides at wavelengths of 380 to 780 nm, an average reflectance (hereinafter also referred to as average reflectance) of 1.0% or less on both sides at wavelengths of 445 to 455 nm, an average reflectance of 1.0% or less on both sides at wavelengths of 515 to 525 nm, an average reflectance of 3.0% or less on both sides at wavelengths of 800 to 870 nm, and a haze value of 0.4% or less on wavelengths of 445 to 455 nm, 515 to 525 nm, and 865 to 875 nm. As a result, the haze value of blue light on the short wavelength side decreases, increasing its transmittance, while the reflectance of red light on the high wavelength side decreases, increasing its transmittance. This improves the transmittance of laser light across a wide wavelength range. In addition, visibility and the accuracy of processed images are improved. From the viewpoint of improving the anti-reflective properties of laser light and increasing transmittance, it is preferable that the anti-reflective coating be a four-layer anti-reflective coating further having the following medium-low refractive index layer below the medium refractive index layer (on the hard coat layer side). Medium-low refractive index layer: refractive index of 1.39-1.49 and layer thickness of 115-175 nm In this case, the refractive index of the intermediate-low refractive index layer must be set higher than that of the low refractive index layer.

[0031] [Medium-low refractive index layer] For the reasons stated above, the optical component of the present invention is preferable if the anti-reflective coating is a four-layer anti-reflective coating having a medium-low refractive index layer. The medium-low refractive index layer is a refractive index layer located at the bottom layer of the anti-reflective coating and is laminated on top of the hard coat layer. The refractive index of the medium-to-low refractive index layer is 1.39 to 1.49, and the layer thickness is 115 to 175 nm. Below 1.39, the luminous mean reflectance at wavelengths of 380 to 780 nm and the average reflectance at wavelengths of 515 to 525 nm are high. Above 1.49, the luminous mean reflectance at wavelengths of 380 to 780 nm is high. From these viewpoints, it is preferably 1.41 to 1.47, and more preferably 1.42 to 1.45. The layer thickness of the low and medium refractive index layer is 115 to 175 nm. If it is less than 115 nm, the average reflectance at wavelengths of 445 to 455 nm will increase. If it exceeds 175 nm, the average reflectance at wavelengths of 445 to 455 nm will also increase. From these viewpoints, it is preferably 130 to 170 nm, and more preferably 150 to 165 nm.

[0032] The low and medium refractive index layer preferably consists of a cured product of a composition containing 5 to 30 parts by mass of silica particles and 1 to 10 parts by mass of a metal chelate compound with respect to 100 parts by mass of at least one binder component selected from the group consisting of an alkoxysilane compound represented by the following formula (1) or its hydrolyzate, an alkoxysilane compound represented by the following formula (2) or its hydrolyzate, and an organic-inorganic composite compound.

Chemical formula

Chemical formula

[0033] (Binder component) The binder component is selected from the alkoxysilane compound represented by the above formula (1) or its hydrolyzate, the alkoxysilane compound represented by the above formula (2) or its hydrolyzate, and an organic-inorganic composite compound, and is used alone or in a combination of multiple components. These binder components are an alkoxysilane compound represented by formula (2) or its hydrolyzate, where R 1 is a methyl group or an ethyl group, and R 2A mixture of different compounds selected from the group of compounds in which n is 0 or 1, where n is a methyl or ethyl group, is preferable in that it reduces the haze value of the layer and further improves crack resistance. Specifically, a combination of tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) is an example.

[0034] (Formula (1) Alkoxysilane compound) It is one of the binder components and is represented by the following formula (1). [ka] In the formula, R is an alkylene group. The number of carbon atoms in the alkylene group is preferably 1 to 9, more preferably 1 to 5. Examples of alkylene groups include methylene, ethylene, trimethylene, propylene, butylene, tetramethylene, pentylene, and hexylene groups. R 1 This is an alkyl group. The number of carbon atoms in the alkyl group is preferably 1 to 9, more preferably 1 to 5. Examples of alkyl groups include methyl, ethyl, trimethyl, propyl, butyl, tetramethyl, pentyl, and hexyl groups. Note that the alkyl group bonded to the silicon atom and the alkyl group of the alkoxy group may be different from each other. Specifically, known compounds such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane are examples. Depending on the type, the alkoxysilane compound of formula (1) may be used as a hydrolyzed product that has been partially hydrolyzed with a dilute acid or the like to improve its solubility in water or solvents. There are no particular restrictions on the method of pre-hydrolysis; methods include hydrolyzing a portion of the compound using an acid catalyst such as acetic acid, or partially hydrolyzing the alkoxysilane compound in combination with an acid in a solution for forming a medium-to-low refractive index layer (described later) along with other components.

[0035] (Formula (2) Alkoxysilane compound) It is one of the binder components and is represented by the following formula (2). [ka] In the formula, R 1 is an alkyl group, and is the same as formula (1). R 2 This is an alkyl group, an alkenyl group, or an alkoxyalkyl group. Alkyl is R 1 It is the same as the alkyl group. The number of carbon atoms in the alkenyl group is preferably 1 to 9, more preferably 1 to 5. Examples of alkenyl groups include ethenyl, propenyl, butenyl, pentyl, and hexenyl groups. The number of carbon atoms in the alkoxyalkyl group is preferably 1 to 9, more preferably 1 to 5. Examples of the alkoxy group in the alkoxyalkyl group include methoxy, ethoxy, and propoxy groups. Examples of the alkyl group in the alkoxyalkyl group include methyl, ethyl, trimethyl, propyl, butyl, tetramethyl, pentyl, and hexyl groups. Specifically, examples of compounds with n=0 include tetraalkoxysilanes such as tetraethoxysilane and tetramethoxysilane; examples of compounds with n=1 include trialkoxysilanes such as methyltrimethoxysilane, ethyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltrimethoxy(ethoxy)silane, and vinyltriethoxysilane; and examples of compounds with n=2 include known compounds such as dialkoxysilanes such as dimethyldimethoxysilane and dimethyldiethoxysilane. The alkoxysilane compound of formula (2) may also be used as a hydrolyzed product that has been partially hydrolyzed beforehand, similar to that of formula (1).

[0036] (organic / inorganic composite compound) It is one of the binder components. This organic-inorganic composite compound is, for example, a composite compound in which an alkoxysilyl group is bonded to a bisphenol A type epoxy compound. Crosslinking of epoxy groups occurs between the compounds, and silica particles are formed by the sol-gel curing of the alkoxysilyl groups, resulting in a cured body that has no Tg like glass and possesses the advantages of both organic and inorganic materials. Organic-inorganic composite compounds include various types of compounds, such as bisphenol A type epoxy compounds, novolacphenol compounds, or polyamic acid compounds, in which an alkoxysilyl group is bonded. In the present invention, a composite compound in which an alkoxysilyl group is bonded to a bisphenol A type epoxy compound is preferred from the viewpoint of being easily heat-curable, having the best layer flexibility and alkali resistance, and being readily available.

[0037] (Silica particles) In the medium-to-low refractive index layer of the present invention, silica particles are used to control the refractive index to 1.39 to 1.49. Two types of silica particles are used: the solid silica particles used in the formation of the hard coat layer, and the hollow silica particles described below. Hollow silica particles are fine hollow particles made of silicon dioxide with a cavity inside, typically with an average particle size of 5 to 150 nm and an outer shell thickness of approximately 1 to 15 nm. It is preferable to select hollow silica particles with a refractive index in the range of 1.20 to 1.38. These hollow silica particles are known from publications such as Japanese Patent Application Publication No. 2001-233611, and are generally available commercially in the form of suspensions dispersed in lower alcohols such as methanol, ethanol, and propanol. Therefore, it is preferable to obtain and use commercially available products. The silica particles are used in an amount of 5 to 30 parts by mass, preferably 5 to 28 parts by mass, per 100 parts by mass of the binder component. In particular, including solid silica particles is preferable in terms of suppressing the shrinkage of binder components such as alkoxysilane compounds due to thermal history. The average particle size of the silica particles is preferably 1 to 10 nm, as this can reduce the haze value, based on the relationship between the average particle size of the particles contained in each layer and the haze value (details will be described later).

[0038] (Metal chelate compounds) The metal chelate compound is a component that functions as a crosslinking agent, making the formed refractive index layer denser. Any compound used in the formation of the hard coat layer can be used without limitation. The above-mentioned metal chelate compound is used in an amount of 1 to 10 parts by mass, preferably 1 to 5 parts by mass, per 100 parts by mass of the binder component. If the amount exceeds 10 parts by mass, the metal chelate compound tends to precipitate in the medium- and low refractive index layers, causing a decrease in anti-reflective and transmission performance and resulting in poor appearance. If the amount is less than 1 part by mass, the strength and hardness of the medium- and low refractive index layers will not improve.

[0039] (Formation of a medium-to-low refractive index layer) The medium- and low refractive index layers are formed by dissolving specific amounts of each of the above components, as well as optional components, in the following organic solvents for the purpose of viscosity adjustment and ease of application, creating a medium- and low refractive index layer forming solution, applying this solution onto the hard coat layer, drying it, and then heating and curing it. For the formation of the medium-to-low refractive index layer, an appropriate amount of an acidic aqueous solution, such as an aqueous hydrochloric acid solution, may be added as an optional component to promote the hydrolysis and condensation of alkoxysilane compounds, etc.

[0040] Suitable organic solvents for solutions forming medium- and low refractive index layers include alcohol compounds such as methyl alcohol, ethyl alcohol, and propyl alcohol; aromatic compounds such as toluene and xylene; ester compounds such as ethyl acetate, isobutyl acetate, and sec-butyl acetate; and ketone compounds such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and diacetone alcohol. Other solvents that can be used include methylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and cellosolve compounds such as methyl cellosolve, ethyl cellosolve, and propylene glycol monomethyl ether. The above-mentioned components constituting the solution for forming the medium- and low-refractive-index layer are usually mixed and stirred at around room temperature to form a solution. When commercially available silica particle dispersions are used, the solvent, which acts as the dispersion medium, will inevitably be mixed into the solution. The solvent in the solution for forming the medium- and low-refractive-index layer, as well as any separately added organic solvents, are removed during the drying and curing process.

[0041] The method for applying the medium-to-low refractive index layer formation solution onto the hard coat layer is not particularly limited. Similar to the formation of the hard coat layer, methods such as dip coating, roll coating, die coating, flow coating, and spraying can be used. However, the dip coating method is preferred from the viewpoint of appearance quality and layer thickness control. After application, the coating is dried, and then heated to heat-cur it, forming a medium-to-low refractive index layer. Drying is usually performed in air at 20-30°C for 0.05-1 hour, and heat curing is usually performed in air at 60-90°C for 0.2-1.0 hour. Drying and heat curing may be performed simultaneously.

[0042] [Intermediate refractive index layer] The refractive index of the intermediate refractive index layer is 1.51 to 1.60. Below 1.51, the luminous mean reflectance at wavelengths of 380 to 780 nm increases, and above 1.60, the average reflectance at wavelengths of 445 to 455 nm increases. From these viewpoints, it is preferably 1.52 to 1.59, and more preferably 1.54 to 1.58. The thickness of the intermediate refractive index layer is 60 to 100 nm. Below 60 nm, the luminous mean reflectance at wavelengths of 380 to 780 nm is high, and above 100 nm, the luminous mean reflectance at wavelengths of 380 to 780 nm and the average reflectance at wavelengths of 445 to 455 nm are high. From these viewpoints, it is preferably 65 to 95 nm, and more preferably 70 to 90 nm. The intermediate refractive index layer consists of a cured product of a composition containing 30 to 100 parts by mass of metal oxide particles and 1 to 10 parts by mass of a metal chelate compound per 100 parts by mass of a binder component.

[0043] (Binder component) As a binder component, at least one selected from the group consisting of alkoxysilane compounds represented by formula (1) or their hydrolysates, alkoxysilane compounds represented by formula (2) or their hydrolysates, and organic-inorganic composite compounds, which were used in the formation of the intermediate-low refractive index layer, can be used without limitation for the same purpose. Formulas (1) and (2) are as described in the section on the intermediate-low refractive index layer. These binder components are particularly preferable to consist of a mixture of at least two compounds selected from the group consisting of alkoxysilane compounds represented by formula (1) or their hydrolysates, alkoxysilane compounds represented by formula (2) or their hydrolysates, and organic-inorganic composite compounds, in order to obtain a layer with a low haze value and excellent crack resistance. Specifically, a combination of 3-glycidoxypropyltrimethoxysilane, which is the compound of formula (1), and tetraethoxysilane, which is the compound of formula (2), is an example.

[0044] (metal oxide particles) Metal oxide particles are incorporated into the intermediate refractive index layer to control the refractive index to the predetermined value. As metal oxide particles, those with a refractive index of 1.51 or higher can be used. For example, it is preferable that the oxide particles be at least one selected from the group consisting of titanium oxide, zirconium oxide, niobium pentoxide, antimony-doped tin oxide (ATO), indium tin oxide (ITO), phosphorus-doped tin oxide (PTO), fluorine-doped tin oxide (FTO), and antimony pentoxide. More specifically, the metal oxide particles used include zirconium oxide particles (refractive index = 2.40), composite zirconium metal oxide particles obtained by molecularly compounding zirconium oxide with other oxides such as silicon oxide to adjust the refractive index, titanium oxide particles (refractive index = 2.71), and composite titanium metal oxide particles obtained by molecularly compounding titanium oxide with other oxides such as silicon oxide or zirconium oxide to adjust the refractive index. These metal oxide particles are combined as appropriate to adjust the refractive index to the desired level. Such particles are publicly known and commercially available. The average particle size of the metal oxide particles is preferably 1 to 30 nm, and more preferably 1 to 20 nm, taking into consideration the effect on the haze value that occurs when stacking each refractive index layer. This is because, when stacking refractive index layers, the upper layer is more susceptible to the influence of the lower layer. For example, if the particle size of the lower layer is large and the difference in particle size between it and the upper layer is large, interfacial diffusion occurs between the two layers, affecting the haze value. However, simply reducing the difference in particle size does not necessarily suppress the haze value; even if the difference in particle size is reduced, the haze value does not decrease easily between large particles. This is because the presence of particles becomes larger within the refractive index layer, making it easier for light to strike the particles. Therefore, by selecting particles with small particle sizes and further reducing the particle size towards the bottom layer of the anti-reflective coating, interfacial diffusion to the upper layer can be suppressed. In addition to the interfacial diffusion mentioned above, internal diffusion occurring within the refractive index layer must also be considered as a factor influencing the haze value. Internal diffusion arises from the difference in refractive index between the binder component and the metal oxide particles, and can be suppressed by reducing the difference in refractive index between the two. Although internal diffusion does not have as significant an impact on the haze value as interfacial diffusion, selecting materials while considering internal diffusion can result in optical components with lower haze values. For the reasons mentioned above and in order to control the refractive index of the intermediate refractive index layer to a predetermined refractive index, metal oxide particles are used in an amount of 30 to 101 parts by mass per 100 parts by mass of the binder component. Zirconium oxide particles are particularly preferred in terms of light resistance.

[0045] (Metal chelate compounds) As for the metal chelate compound, any metal chelate compound used for forming the intermediate-low refractive index layer can be used without limitation for the same purpose. The content of the metal chelate compound in the intermediate refractive index layer is 1 to 10 parts by mass, preferably 1 to 5 parts by mass, per 100 parts by mass of the binder component. If the content exceeds 10 parts by mass, the metal chelate compound tends to precipitate in the intermediate refractive index layer, causing a decrease in anti-reflective and transmission performance and poor appearance. If the content is less than 1 part by mass, the strength and hardness of the intermediate refractive index layer will not improve.

[0046] (Formation of the intermediate refractive index layer) The intermediate refractive index layer is formed by dissolving specific amounts of each of the above components, and also optional components, in an organic solvent to create a solution for forming the intermediate refractive index layer. This solution is then applied to the intermediate and low refractive index layer, dried, and subsequently heated to cure it. The organic solvents used, the mixing order and conditions of each component, as well as the coating method, drying and heating methods, etc., shall conform to the method for forming a medium-to-low refractive index layer.

[0047] [High refractive index layer] Anti-reflective coatings have a high refractive index layer between the medium refractive index layer and the low refractive index layer to achieve high anti-reflective performance. As a result, they exhibit both high anti-reflective performance and high transmission performance. The refractive index of the high refractive index layer is 1.65 to 1.80. Below 1.65, the luminous mean reflectance is high, and above 1.80, the luminous mean reflectance is low, but the average reflectance tends to be high above 850 nm, making it difficult to control the average reflectance up to 870 nm. From these viewpoints, it is preferably 1.67 to 1.78, and more preferably 1.72 to 1.75. The thickness of the high refractive index layer is 150 to 190 nm. Below 150 nm, the average reflectance is high at wavelengths of 445 to 455 nm, 515 to 525 nm, and 800 to 870 nm, while above 190 nm, the average reflectance is high at wavelengths of 445 to 455 nm. From these viewpoints, it is preferably 150 to 180 nm, and more preferably 160 to 180 nm. The high refractive index layer is typically formed by curing a composition containing 150 to 350 parts by mass of metal oxide particles and 0.5 to 10 parts by mass of a metal chelate compound, with respect to 100 parts by mass of the binder component described below.

[0048] (Binder component) As a binder component, at least one selected from the group consisting of the alkoxysilane compound represented by formula (1) or its hydrolysate, and the alkoxysilane compound represented by formula (2) or its hydrolysate, which were used in the formation of the intermediate-low refractive index layer, can be used without limitation for the same purpose. Formulas (1) and (2) are as described in the section on the intermediate-low refractive index layer.

[0049] (metal oxide particles) Metal oxide particles are incorporated into the high refractive index layer to control the refractive index to the predetermined level. The metal oxide particles used in forming the medium refractive index layer are used without limitation. The above-mentioned metal oxide particles are appropriately selected from a range of 150 to 350 parts by mass, preferably 190 to 330 parts by mass, per 100 parts by mass of the binder component, so as to satisfy the predetermined refractive index. Furthermore, to improve scratch resistance, the aforementioned solid silica particles may be used in an amount of 0 to 0.1 parts by mass per 100 parts by mass of the binder component.

[0050] (Metal chelate compounds) As binder components, metal chelate compounds used for forming the medium- and low-refractive-index layers can be used without limitation for the same purpose. The content of the metal chelate compound in the high refractive index layer is 0.5 to 10 parts by mass, preferably 0.5 to 7 parts by mass, per 100 parts by mass of the binder component. If the content exceeds 10 parts by mass, the metal chelate compound tends to precipitate in the high refractive index layer, causing a decrease in anti-reflective and transmission performance, as well as poor appearance.

[0051] (Formation of a high refractive index layer) The high refractive index layer is formed by dissolving specific amounts of each of the above components, and also optional components, in an organic solvent to create a solution for forming the high refractive index layer. This solution is then applied to the medium refractive index layer, dried, and subsequently heated to cure it. The organic solvents used, the mixing order and conditions of each component, as well as the coating method, drying and heating methods, etc., shall conform to the method for forming a medium-to-low refractive index layer.

[0052] [Low refractive index layer] This is the refractive index layer located on the outermost layer (viewing side) of the anti-reflective coating, and is an essential layer for the anti-reflective laminate of the present invention to exhibit anti-reflective performance. The refractive index of the low refractive index layer is 1.33 to 1.40. Below 1.33, the luminous mean reflectance decreases, but the average reflectance on both sides increases at wavelengths of 445 to 455 nm and 870 nm and beyond. Above 1.40, the luminous mean reflectance increases. From these viewpoints, it is preferably 1.34 to 1.38, and more preferably 1.35 to 1.37. The thickness of the low refractive index layer is 70 to 90 nm. Below 70 nm, the luminous mean reflectance at wavelengths of 380 to 780 nm and the average reflectance at wavelengths of 800 to 870 nm are high, while above 90 nm, the luminous mean reflectance at wavelengths of 380 to 780 nm and the average reflectance at wavelengths of 445 to 455 nm and 515 to 525 nm are high. From these viewpoints, it is preferably 75 to 90 nm, and more preferably 75 to 85 nm. The low refractive index layer is typically formed by curing a composition containing 90 to 110 parts by mass of silica particles and 1 to 10 parts by mass of a metal chelate compound, with respect to 100 parts by mass of the binder component described below.

[0053] (Binder component) As a binder component, at least one selected from the group consisting of the alkoxysilane compound represented by formula (1) or its hydrolysate, and the alkoxysilane compound represented by formula (2) or its hydrolysate, which were used in the formation of the intermediate-low refractive index layer, can be used without limitation for the same purpose. Formulas (1) and (2) are as described in the section on the intermediate-low refractive index layer.

[0054] (Silica particles) In the low refractive index layer, silica particles are used to control the refractive index to 1.33-1.40. These silica particles are the same hollow silica particles used in the formation of the medium-low refractive index layer, and can be used without restriction. The hollow silica particles are used in an amount of 90 to 110 parts by mass per 100 parts by mass of the binder component.

[0055] (Metal chelate compounds) As for the metal chelate compound, any metal chelate compound used for forming the intermediate-low refractive index layer can be used without limitation for the same purpose. The content of the metal chelate compound in the low refractive index layer is 1 to 10 parts by mass, preferably 1 to 7 parts by mass, per 100 parts by mass of the binder component. If the content exceeds 10 parts by mass, the metal chelate compound tends to precipitate in the low refractive index layer, causing a decrease in anti-reflective and transmission performance, as well as poor appearance.

[0056] (Formation of a low refractive index layer) The low refractive index layer is formed by dissolving specific amounts of each of the above components, and also optional components, in an organic solvent to create a solution for forming the low refractive index layer. This solution is then applied to the high refractive index layer, dried, and subsequently heated to cure it. The organic solvents used, the mixing order and conditions of each component, as well as the coating method, drying and heating methods, etc., shall conform to the method for forming a medium-to-low refractive index layer.

[0057] <Protective layer> The optical component of the present invention has, as its outermost layer, a protective layer on top of the anti-reflective film to protect the anti-reflective film and to make the thickness of the anti-reflective film uniform. From the viewpoint of anti-reflective properties and transmittance, the protective layer needs to have a refractive index of 1.49 to 1.50 and a layer thickness of 10 to 25 nm. The protective layer is preferably made of a cured product of a composition containing the following binder components, silica particles, and a metal chelate compound. A typical example is a cured product of a composition containing 1 to 10 parts by mass of solid silica particles and 1 to 10 parts by mass of a metal chelate compound per 100 parts by mass of the binder component.

[0058] (Binder component) As a binder component, at least one selected from the group consisting of the alkoxysilane compound represented by formula (1) or its hydrolysate, and the alkoxysilane compound represented by formula (2) or its hydrolysate, which were used in the formation of the intermediate-low refractive index layer, can be used without limitation for the same purpose. Formulas (1) and (2) are as described in the section on the intermediate-low refractive index layer.

[0059] (Solid silica particles) The protective layer uses solid silica particles, the same particles used to form the medium-to-low refractive index layer, in order to control the refractive index to 1.49-1.50 and achieve a predetermined hardness. The solid silica particles are used in an amount of 1 to 10 parts by mass, preferably 2 to 7 parts by mass, per 100 parts by mass of the binder component.

[0060] (Metal chelate compounds) As for the metal chelate compound, any metal chelate compound used for forming the intermediate-low refractive index layer can be used without limitation for the same purpose. The amount of metal chelate compound in the protective layer is 1 to 10 parts by mass, preferably 3 to 8 parts by mass, per 100 parts by mass of the binder component. If it exceeds 10 parts by mass, the metal chelate compound tends to precipitate in the protective layer, causing a decrease in anti-reflective and transmission performance, as well as poor appearance.

[0061] (Formation of a protective layer) The protective layer is formed by dissolving specific amounts of each of the above components, as well as optional components, in an organic solvent to create a protective layer-forming solution. This solution is then applied to the low refractive index layer, dried, and subsequently heated to cure it. The organic solvents used, the mixing order and conditions of each component, as well as the coating method, drying and heating methods, etc., shall conform to the method for forming a medium-to-low refractive index layer.

[0062] <Characteristics of optical components> [Average luminous reflectance of both sides] The luminous mean reflectance of both sides of the optical component surface of the present invention at wavelengths of 380 to 780 nm is 0.8% or less. Preferably, it is 0.7% or less, and more preferably, 0.6% or less. As is clear from comparing the reflectance distribution of the optical element of Example 4 shown in Figure 1 with the reflectance distribution of the optical element of Comparative Example 16 shown in Figure 2, the optical element of the present invention exhibits low reflectance over a wide wavelength range.

[0063] [Average reflectance of both sides] The average reflectance of both sides of the optical member surface of the present invention at wavelengths of 445 to 455 nm is 1.0% or less, preferably 0.9% or less, and more preferably 0.85% or less. The average reflectance of both sides at wavelengths of 515 to 525 nm is 1.0% or less, preferably 0.8% or less, and more preferably 0.6% or less. The average reflectance of both sides at wavelengths of 800 to 870 nm is 3.0% or less, preferably 2.5% or less, and more preferably 2.0% or less.

[0064] [Haze value] The haze value of the optical component of the present invention is 0.4% or less at wavelengths of 445-455 nm, 515-525 nm, and 865-875 nm. Preferably, it is 0.3% or less in each wavelength range, and more preferably 0.1% or less in each wavelength range. The haze value is a physical property that indicates the degree of light scattering of an object. A small haze value indicates less scattering of light at each of the above wavelengths and superior transmittance. A haze value of 0.4% or less suppresses the diffusion of laser light, allowing for the acquisition of clear images. [Examples]

[0065] The present invention will be described in detail below with reference to examples, but the present invention is not limited in any way by these examples. Furthermore, not all combinations of features described in the examples are necessarily essential to the solutions of the present invention. The various components, abbreviations, and test methods used in the following examples and comparative examples are as follows.

[0066] (Acrylate) Monofunctional A: Monofunctional acrylate containing one acrylate group Difunctional A: Triethylene glycol diacrylate Trifunctional A: Acrylate having three acrylate groups (Urethane acrylate) Trifunctional UA: Urethane acrylate having three acrylate groups at its terminus. Hexafunctional UA: Urethane acrylate having six acrylate groups at its terminus. (Silane coupling agent) γ-GPS:3-Glycidoxypropyltrimethoxysilane (Binder component) TEOS: Tetraethoxysilane MTES: Methyltriethoxysilane γ-GPS:3-Glycidoxypropyltrimethoxysilane Organic / inorganic composite compounds: ASE: Bisphenol A type epoxy compound modified with a trialkoxymethylsilyl group (alkoxy group-containing silane-modified epoxy compound) Dispersion solvent: Diethylene glycol dimethyl ether (DGDE) (Metal chelate compounds) AlTA: Tris(acetylacetonate)aluminum (Silica particles) Hollow silica particles: Average particle size 60 nm, refractive index 1.30, solid content 20% by weight. Dispersion solvent IPA Solid silica particles 1: Average particle size 7 nm, refractive index 1.46, solid content 20% by weight. Dispersion solvent IPA Solid silica particles 2: Average particle size 300 nm, refractive index 1.46, solid content 20% by weight. Dispersion solvent IPA (metal oxide particles) Zirconium oxide particles 1: Average particle size 20.7 nm, refractive index 2.40, solid content 30% by weight. Dispersion solvent: methanol (MA) Zirconium oxide particles 2: Average particle size 24 nm, refractive index 2.40, solid content 15% by weight. Dispersion solvent: Mixture of n-butanol (NBA) and ethanol (EA) Zirconium oxide particles 3: Average particle size 60 nm, refractive index 2.42, solid content 55% by weight. Dispersion solvent: Propylene glycol monomethyl ether (PGM) Titanium dioxide particles 1: Average particle size 20 nm, refractive index 2.71, solid content 11% by weight. Dispersion solvent: Methanol (MA) and ethanol (EA) mixture Titanium dioxide particles 2: Average particle size 20 nm, refractive index 2.71, solid content 20% by weight. Dispersion solvent: methanol (MA) (Photopolymerization initiator) HCHP: 1-Hydroxycyclohexylphenyl ketone MMMP: 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (UV absorber) BTA: Benzotriazole-based UV absorber (Hydrolysis catalyst) HCl: 0.05N hydrochloric acid (Organic solvents) IPA: Isopropyl alcohol Ethacol: Ethyl alcohol / isopropyl alcohol mixture NPA: n-propyl alcohol SBAC: s-butyl acetate MIBK: Methyl isobutyl ketone DAA: Diacetone alcohol

[0067] [Refractive index of each layer] The solutions for forming each layer were applied to an acrylic resin substrate and cured to form each refractive index layer or protective layer. The refractive index of each layer was calculated from the reflectance of the reflectance spectrum of each layer, with the peak of the reflectance spectrum adjusted to 550 nm, using a JASCO V-650 ultraviolet-visible spectrophotometer.

[0068] [Thickness of each layer] The layer thickness was determined by simulations that referenced the reflectance spectrum obtained from actual spectral data measurements.

[0069] [Average luminous reflectance of both sides] The luminous mean reflectance of both sides (hereinafter referred to as luminous mean reflectance) was measured using the following method. A UV-Vis spectrophotometer V-650 manufactured by JASCO Corporation was used to measure spectral reflectance from 380 nm to 780 nm, and the reflectance was calculated by multiplying it by a weighting factor based on JIS Z 8722. Specifically, it is expressed as the average value of the product of the reflectance at 10 nm intervals in the 380 to 780 nm wavelength range with each specific weighting factor. A larger value indicates poorer anti-reflection performance and lower light transmittance.

[0070] [Average reflectance of both sides] The average reflectance of both surfaces (hereinafter referred to as average reflectance) was measured using the following method. Spectral reflectance was measured using a JASCO "UV-Vis Spectrophotometer V-650," and the average reflectance for each 1 nm in the wavelength ranges of 445-455 nm, 515-525 nm, and 800-870 nm was calculated.

[0071] [Haze value] Using a JASCO V-650 UV-Vis spectrophotometer, diffuse transmittance was measured from 380 to 870 nm, and the haze value was calculated by dividing this diffuse transmittance by the total light transmittance. Specifically, the haze value was calculated by averaging the values ​​obtained by dividing the diffuse transmittance at 1 nm intervals in each wavelength range of 445-455 nm, 515-525 nm, and 865-875 nm by the total light transmittance. The total light transmittance was measured using the aforementioned measuring device.

[0072] <Solution for forming a hard coat layer> The hard coat layer forming solutions (HC-1, HC-2) were prepared by mixing each component shown in Table 1 in the proportions shown in Table 1.

[0073] [Table 1]

[0074] <Solution for forming anti-reflection film> (Solution for forming medium- and low refractive index layers) The components shown in Table 2 were mixed in the amounts shown in Table 2 to prepare a solution for forming a medium-to-low refractive index layer (ml-1 to ml-6).

[0075] [Table 2]

[0076] (Solution for forming a medium refractive index layer) The components shown in Table 3 were mixed in the proportions shown in Table 3 to prepare solutions for forming the intermediate refractive index layer (m-1 to m-9).

[0077] [Table 3]

[0078] (Solution for forming a high refractive index layer) The components shown in Table 4 were mixed in the proportions shown in Table 4 to prepare a solution for forming a high refractive index layer (h-1 to h-8).

[0079] [Table 4]

[0080] (Solution for forming a low refractive index layer) The components shown in Table 5 were mixed in the proportions shown in Table 5 to prepare solutions for forming a low refractive index layer (l-1 to l-5).

[0081] [Table 5]

[0082] (Protective layer forming solution) A protective layer-forming solution (cv-1) was prepared by mixing each component shown in Table 6 in the proportions shown in Table 6.

[0083] [Table 6]

[0084] Example 1 A hard coat layer, an anti-reflective film, and a protective layer were formed in the following order on a 1 mm thick polymethyl methacrylate (PMMA) substrate using the method described below. The layer thickness was adjusted by the withdrawal speed from the forming solution after dipping each layer.

[0085] [Formation of the hard coat layer] After dipping the substrate in a hard coat layer forming solution (HC-1), it was dried at 60°C for 8 minutes, and then UV cured at 500 mJ to obtain a laminate on which a hard coat layer with a thickness of 1.8 μm was formed on the substrate.

[0086] [Formation of anti-reflective coating] On the above laminate, a medium refractive index layer, a high refractive index layer, and a low refractive index layer were sequentially formed according to the following procedure. The above laminate was dipped in a medium refractive index layer forming solution (m-1), then dried and cured at 90°C for 15 minutes to form a medium refractive index layer with a thickness of 85 nm on the hard coat layer. Next, the laminate was dipped in a high refractive index layer formation solution (h-1), and then dried and cured at 100°C for 15 minutes to form a high refractive index layer with a thickness of 165 nm on the medium refractive index layer. Next, the laminate was dipped in a low refractive index layer forming solution (l-1), dried and cured at 100°C for 15 minutes, and a low refractive index layer with a thickness of 77 nm was formed on the high refractive index layer to produce a laminate having three anti-reflective coatings.

[0087] [Formation of a protective layer] A protective layer was formed on the laminate having the anti-reflective film described above by the following procedure. The laminate was dipped in a protective layer-forming solution (CV-1), then dried and cured at 100°C for 15 minutes to form a protective layer with a thickness of 20 nm, thereby producing the optical component of the present invention. The luminous mean reflectance, mean reflectance in a specific wavelength range, and haze value of the obtained optical components were measured according to the method described above and are shown in Table 8. The combination of layer-forming solutions (composition of each layer), refractive index, and layer thickness are shown in Table 7.

[0088] Example 2 In Example 1, before forming the medium refractive index layer, a medium-low refractive index layer was formed on the hard coat layer using the following method. A laminate with hard coat layers was dipped in a solution for forming a medium-low refractive index layer, and then dried and cured at 90°C for 15 minutes to form a medium-low refractive index layer with a thickness of 160 nm. An optical component having four anti-reflective coatings was fabricated in the same manner as in Example 1. The luminous mean reflectance, mean reflectance in a specific wavelength range, and haze value of the obtained optical components were measured according to the method described above and are shown in Table 8. The combination of layer-forming solutions (composition of each layer), refractive index, and layer thickness are shown in Table 7.

[0089] Examples 3-12 An optical component having four anti-reflective coatings was fabricated in the same manner as in Example 2, except that the anti-reflective coatings and protective coatings were used in the combinations shown in Table 7. The luminous mean reflectance, mean reflectance in a specific wavelength range, and haze value of the obtained optical components were measured according to the method described above and are shown in Table 8. The combination of layer-forming solutions (composition of each layer), refractive index, and layer thickness are shown in Table 7. Figure 1 shows the reflectance distribution of the optical components obtained in Example 4.

[0090] [Table 7]

[0091] [Table 8]

[0092] Comparative Example 1 An optical component having three anti-reflective coatings was fabricated in the same manner as in Example 1, except that the thickness of the protective layer was set to 5 nm. The combination of each layer-forming solution (composition of each layer), refractive index, and layer thickness are shown in Table 9. The luminous mean reflectance, mean reflectance in a specific wavelength range, and haze value of the obtained optical component were measured according to the method described above and are shown in Table 11.

[0093] Comparative Examples 2-10, 17-20 An optical component having three anti-reflective coatings was fabricated in the same manner as in Example 1, except that the anti-reflective coating solutions and protective coating solutions were used in the combinations shown in Table 9. The luminous mean reflectance, mean reflectance in a specific wavelength range, and haze value of the obtained optical components were measured according to the method described above and are shown in Tables 11 and 12.

[0094] [Table 9]

[0095] Comparative Example 11 An optical component having four anti-reflective coatings was fabricated in the same manner as in Example 2, except that the thickness of the medium-low refractive index layer was changed to 110 nm. The combination of each layer-forming solution (composition of each layer), refractive index, and layer thickness are shown in Table 10. The luminous mean reflectance, mean reflectance in a specific wavelength range, and haze value of the obtained optical component were measured according to the method described above and are shown in Table 12.

[0096] Comparative Examples 12-16 An optical component having four anti-reflective coatings was fabricated in the same manner as in Example 2, except that the anti-reflective layer formation solutions and protective layer formation solutions were used in the combinations shown in Table 10. The luminous mean reflectance, mean reflectance in a specific wavelength range, and haze value of the obtained optical component were measured according to the method described above and are shown in Table 12. Figure 2 shows the reflectance distribution of the optical component obtained in Comparative Example 16.

[0097] [Table 10]

[0098] [Table 11]

[0099] [Table 12]

[0100] Comparative Examples 1 to 10 are examples of three-layer anti-reflective coatings. Comparative Example 1 is a case where the thickness of the protective layer is small, resulting in poor luminous mean reflectance. The lowest reflectance value appears on the short-wavelength side, leading to higher reflectance on the long-wavelength side, and the average reflectance at wavelengths of 515-525nm and 800-870nm is also poor. Comparative Example 2 is a case where the thickness of the protective layer is large, resulting in very poor luminous mean reflectance. The lowest reflectance value appears on the long-wavelength side, resulting in poor average reflectance at wavelengths of 445-455nm and 515-525nm. Comparative Example 3 is a case where the thickness of the low refractive index layer is small, resulting in poor luminous mean reflectance. The lowest reflectance value appears on the short wavelength side, leading to higher reflectance on the long wavelength side, and the average reflectance at wavelengths of 515-525 nm and 800-870 nm is also poor. Comparative Example 4 is a case where the thickness of the low refractive index layer is large, resulting in very poor luminous mean reflectance. The lowest reflectance value appears on the long wavelength side, resulting in poor average reflectance at wavelengths of 445-455 nm and 515-525 nm.

[0101] Comparative Example 5 is a case where the thickness of the high refractive index layer is small, resulting in inferior average reflectance at wavelengths of 445-455 nm, 515-525 nm, and 800-870 nm. Comparative Example 6 is a case where the thickness of the high refractive index layer is large, resulting in inferior average reflectance at wavelengths of 445-455 nm because the lowest reflectance value appears on the longer wavelength side. Comparative Example 7 is a case where the thickness of the medium refractive index layer is small, resulting in high reflectance in the medium wavelength range and poor luminous mean reflectance. Comparative Example 8 is a case where the thickness of the medium refractive index layer is large, resulting in poor luminous mean reflectance, high reflectance around 500 nm wavelength, and poor average reflectance at wavelengths of 515-525 nm.

[0102] Comparative Example 9 is a case where the refractive index of the intermediate refractive index layer is low, resulting in a very poor luminous mean reflectance. The reflectance is high around a wavelength of 500 nm, and the average reflectance at wavelengths of 515-525 nm is also poor. Comparative Example 10 is a case where the refractive index of the intermediate refractive index layer is high, resulting in the lowest reflectance value appearing around a wavelength of 500 nm, and the average reflectance at wavelengths of 445-455 nm is poor. Comparative Examples 11-16 are examples of four-layer anti-reflective coatings. Comparative Example 11 is a case where the thickness of the intermediate-low refractive index layer is small, resulting in a high reflectance at a wavelength of 450 nm and a poor average reflectance at wavelengths of 445-455 nm. Comparative Example 12 is a case where the thickness of the intermediate-low refractive index layer is large, resulting in a high reflectance at a wavelength of 450 nm and a poor average reflectance at wavelengths of 445-455 nm.

[0103] Comparative Example 13 is a case where the refractive index of the mid-to-low refractive index layer is low, resulting in high reflectance at a wavelength of 500 nm and poor average reflectance at wavelengths of 515-525 nm. In addition, because large silica particles are used, internal diffusion increases, and the haze value at wavelengths of 445-455 nm also tends to be poor. Comparative Example 14 is a case where the refractive index of the mid-to-low refractive index layer is high, resulting in high reflectance in the mid-wavelength range and very poor luminous average reflectance. Comparative Example 15 is a case where the refractive index of the intermediate refractive index layer is high, and the lowest reflectance value appears around a wavelength of 500 nm, with the average reflectance being inferior at wavelengths of 445-455 nm and 800-870 nm. In addition, because large-particle-sized metal oxide particles are used, internal diffusion is large, and the haze values ​​at wavelengths of 445-455 nm and 515-525 nm tend to be inferior. Comparative Example 16 is a case where the refractive index of the intermediate refractive index layer is low, and the reflectance at a wavelength of 500 nm is high, while the average reflectance at wavelengths of 515-525 nm is inferior.

[0104] Comparative Examples 17-20 are examples of three-layer anti-reflective coatings. Comparative Example 17 uses a low refractive index layer, resulting in poor average reflectance at wavelengths of 445-455 nm. Comparative Example 18 uses a low refractive index layer with a high refractive index, resulting in very high luminous average reflectance, and poor average reflectance at wavelengths of 445-455 nm and 515-525 nm. Comparative Example 19 uses a high refractive index layer with a low refractive index, resulting in inferior luminous mean reflectance and inferior average reflectance at wavelengths of 445-455 nm. Comparative Example 20 uses a high refractive index layer with a high refractive index, resulting in inferior average reflectance at wavelengths of 445-455 nm.

Claims

1. An optical component comprising a transparent resin substrate, a hard coat layer, an anti-reflective film, and a protective layer in this order, The anti-reflective coating is applied from the hard coat layer side, A medium refractive index layer with a refractive index of 1.51 to 1.60 and a layer thickness of 60 to 100 nm, A high refractive index layer with a refractive index of 1.65 to 1.80 and a layer thickness of 150 to 190 nm, A low refractive index layer with a refractive index of 1.33 to 1.40 and a layer thickness of 70 to 90 nm It is composed in the following order: The protective layer has a refractive index of 1.49 to 1.50 and a layer thickness of 10 to 25 nm. The aforementioned intermediate refractive index layer is made up of 100 parts by mass of at least one binder component selected from the group consisting of an alkoxysilane compound represented by the following formula (1) or its hydrolysate, an alkoxysilane compound represented by the following formula (2) or its hydrolysate, and an organic-inorganic composite compound. 【Chemistry 1】 (In the formula, R is an alkylene group, R １ (where m is an alkyl group, and m is 0 or 1.) 【Chemistry 2】 (In the formula, R １ R is an alkyl group. ２ (where n is an alkyl group, an alkenyl group, or an alkoxyalkyl group; n is 0, 1, or 2.) The composition consists of a cured product obtained by hydrolysis and condensation of a composition containing 30 to 100 parts by mass of metal oxide particles and 1 to 10 parts by mass of a metal chelate compound. The anti-reflective film has a medium-low refractive index layer on the hard coat layer side of the medium refractive index layer, with a refractive index of 1.39 to 1.49 and a thickness of 115 to 175 nm. The medium-low refractive index layer is composed of 100 parts by mass of at least one binder component selected from the group consisting of an alkoxysilane compound represented by the following formula (1) or its hydrolysate, an alkoxysilane compound represented by the following formula (2) or its hydrolysate, and an organic-inorganic composite compound. 【Transformation 3】 (In the formula, R is an alkylene group, R １ (where m is an alkyl group, and m is 0 or 1.) 【Chemistry 4】 (In the formula, R １ R is an alkyl group. ２ is an alkyl group, alkenyl group or alkoxy group This is a lukyl group. (n is 0, 1, or 2.) The composition consists of a cured product obtained by hydrolysis and condensation of a composition containing 5 to 30 parts by mass of silica particles and 1 to 10 parts by mass of a metal chelate compound. The optical member is characterized in that the luminous mean reflectance of both sides at wavelengths of 380 to 780 nm is 0.8% or less, the average reflectance of both sides at wavelengths of 445 to 455 nm is 1.0% or less, the average reflectance of both sides at wavelengths of 515 to 525 nm is 1.0% or less, the average reflectance of both sides at wavelengths of 800 to 870 nm is 3.0% or less, and the haze value at wavelengths of 445 to 455 nm, 515 to 525 nm, and 865 to 875 nm are all 0.4% or less.

2. The optical member according to claim 1, characterized in that the binder component of the intermediate refractive index layer consists of at least two selected from the group consisting of an alkoxysilane compound represented by the following formula (1) or its hydrolysate, an alkoxysilane compound represented by the following formula (2) or its hydrolysate, and an organic-inorganic composite compound. 【Transformation 5】 (In the formula, R is an alkylene group, R １ (where m is an alkyl group, and m is 0 or 1.) 【Transformation 6】 (In the formula, R １ is an alkyl group. R ２ is an alkyl group, an alkenyl group or an alkoxyalkyl group. n is 0, 1 or 2.)

3. The optical member according to claim 2, characterized in that the intermediate refractive index layer binder component consists of 3-glycidoxypropyltrimethoxysilane and tetraethoxysilane.

4. The optical member according to claim 1, characterized in that the average particle size of the metal oxide particles is 1 to 30 nm.

5. The binder component of the medium-low refractive index layer is an alkoxysilane compound represented by the following formula (2) or its hydrolysate, R １ is a methyl group or an ethyl group, R ２ The optical member according to claim 1, characterized in that it is a mixture of different compounds selected from the group of compounds in which n is a methyl group or an ethyl group and n is 0 or 1. 【Transformation 7】 (In the formula, R １ R is an alkyl group. ２ (where n is an alkyl group, an alkenyl group, or an alkoxyalkyl group; n is 0, 1, or 2.)

6. The optical member according to claim 1, characterized in that the average particle size of the silica particles is 1 to 10 nm.

7. The optical member according to claim 1, characterized in that the organic-inorganic composite compound of the intermediate refractive index layer and / or the intermediate-low refractive index layer is a composite compound having a structure in which an alkoxysilyl group is bonded to a bisphenol A type epoxy compound, a novolacphenol compound, or a polyamic acid compound.

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