Lens manufacturing method

Abstract

The present invention addresses the problem of providing a lens manufacturing method capable of manufacturing a lens having a hard coat layer excellent in covering property in which circular defects and spiral defects are less likely to be observed. This lens manufacturing method is for manufacturing a lens by coating a lens substrate with a hard coat layer-forming composition by a spin coat method to form a hard coat layer. In the spin coat method, the hard coat layer-forming composition in a predetermined amount is discharged while a nozzle for discharging the hard coat layer-forming composition from the tip thereof is being linearly moved from a predetermined first position to a predetermined second position located on the opposite side of the center of the lens substrate from the first position through the center of the lens substrate while the lens substrate is being rotated.

Description

Lens manufacturing method

[0001] The present disclosure relates to a method for manufacturing a lens.

[0002] Patent Document 1 discloses a method for manufacturing a heat mode type optical information recording medium having a recording layer on a substrate on which information can be recorded by irradiation with laser light, in which a solution for forming the recording layer is applied to the substrate while the substrate is being rotated, and the rotation speed of the substrate is increased when the solution is applied to the inner peripheral side of the substrate.

[0003] Japanese Patent Application Laid-Open No. 2000-155994

[0004] The present disclosure relates to a method for manufacturing a lens, which comprises applying a hard coat layer-forming composition to a lens substrate by spin coating to form a hard coat layer, and manufacturing the lens, wherein, in the spin coating method, while rotating the lens substrate, a nozzle that discharges the hard coat layer-forming composition from its tip is moved linearly from a first position through the center of the lens substrate to a second position located between the first position and the center of the lens substrate, and the hard coat layer-forming composition is discharged at an amount of 0.0007 g / mm with respect to a projected area of ​​the lens substrate projected from the optical axis direction of the lens substrate. ２ the first position is located between a position that is 15.0% of the radius of the lens substrate from the center of the lens substrate and the center of the lens substrate, and the second position is located between a position that is 15.0% of the radius of the lens substrate from the center of the lens substrate and a position that is 25.0% of the radius of the lens substrate from the center of the lens substrate.

[0005] 1A and 1B are schematic cross-sectional views showing a method for manufacturing a lens of the present disclosure, a diagram showing positional relationships in the method for manufacturing a lens of the present disclosure, and a cross-sectional view of one embodiment of a lens obtained by the method for manufacturing a lens of the present disclosure.

[0006] The present disclosure will be described in detail below. The lens manufacturing method of the present disclosure can manufacture a lens having a hard coat layer with excellent coverage and with which round defects and spiral defects are less likely to be observed. The following explanation of the constituent elements may be based on representative embodiments of the present disclosure, but the present disclosure is not limited to such embodiments.

[0007] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits. Furthermore, in this specification, when two or more types of a component are present, the "content" of that component means the total content of those two or more components. In this specification, in a numerical range described in stages, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in a numerical range described in this specification, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the Examples. In this specification, a combination of two or more preferred embodiments is a more preferred embodiment.

[0008] In this specification, the "solid content" of a composition refers to the components that form a layer formed using the composition, and in the case where the composition contains a solvent (e.g., an organic solvent and water), refers to all components excluding the solvent. Furthermore, liquid components that form a layer formed using the composition are also considered to be solid content. In this specification, "(meth)acrylic" is a concept that encompasses either or both acrylic and methacrylic, and the terms "(meth)acrylate" and "(meth)acryloyl" have the same meaning.

[0009] <Lens Manufacturing Method> The lens manufacturing method of the present disclosure is a method of forming a hard coat layer by applying a hard coat layer-forming composition to a lens substrate by spin coating. Application by spin coating is generally carried out by placing the lens substrate on a spin coater equipped with a pedestal that can fix and rotate the substrate, and ejecting the hard coat layer-forming composition from a nozzle onto the surface of the substrate while the lens substrate is rotating. This allows the hard coat layer-forming composition to be applied to the entire surface of the substrate by centrifugal force.

[0010] The shape of the surface of the lens substrate on which the composition for forming a hard coat layer is formed by spin coating (the surface to be coated) may be any of a flat, convex, and concave shape, and is often a convex shape. When the surface of the lens substrate to be coated has a convex or concave shape, the radius of curvature thereof is preferably 50 to 2500 mm, and more preferably 100 to 1000 mm.

[0011] In the spin coating method, the rotation speed of the lens substrate during the supply of the hard coat layer-forming composition is preferably 100 to 500 rpm (rotation per minute), more preferably 200 to 400 rpm, and even more preferably 250 to 350 rpm, from the viewpoint of film thickness uniformity. The rotation speed of the lens substrate during the supply of the hard coat layer-forming composition may be constant or may vary according to a predetermined program, but is preferably constant. After the supply of the hard coat layer-forming composition, the hard coat layer-forming composition is spread over the entire surface of the lens substrate, and the rotation speed of the substrate may be changed to remove unnecessary hard coat layer-forming composition. The rotation speed of the lens substrate after the supply of the hard coat layer-forming composition is not particularly limited, but is preferably equal to or higher than the rotation speed of the substrate during the supply of the hard coat layer-forming composition, with the upper limit preferably being 2000 rpm or less. The rotation speed of the lens substrate after the supply of the hard coat layer-forming composition may be constant or may vary, and it is preferable to gradually increase the rotation speed.

[0012] The temperature of the lens substrate when supplying the hard coat layer-forming composition is not particularly limited, but is preferably 10 to 50°C, more preferably 15 to 40°C, from the viewpoint of the coating properties of the hard coat layer-forming composition.

[0013] The amount of the composition for forming a hard coat layer discharged from the nozzle was 0.0007 g / mm with respect to the projected area of ​​the lens substrate projected in the direction of the optical axis of the lens substrate. ２ The above results indicate that the effects of the present disclosure are even more excellent. ２ More than 0.0008 g / mm ２ The upper limit of the discharge amount relative to the projected area of ​​the lens substrate projected in the direction of the optical axis of the lens substrate is 0.0009 g / mm in terms of film thickness. ２ Preferably, 0.00085 g / mm ２ The following is more preferable. The above-mentioned discharge amount (g) is the discharge amount (g) from the start of discharge of the composition for forming a hard coat layer to the end of discharge. In the production method of the present disclosure, by setting the discharge amount of the composition for forming a hard coat layer from the nozzle as described above, it is presumed that swirl defects can be suppressed even when, for example, a composition for forming a hard coat layer having a relatively high viscosity is used.

[0014] In the present disclosure, when discharging the hard coat layer-forming composition, the nozzle moves linearly from a first position through the center of the lens substrate to a second position located between the first position and the center of the lens substrate. During this process, the nozzle movement speed and discharge rate are controlled so that discharge starts from the first position and ends at the second position, and the above-mentioned discharge amount is achieved. The discharge rate of the hard coat layer-forming composition from the nozzle can be appropriately selected depending on the discharge rate of the hard coat layer-forming composition and the nozzle movement distance, but is preferably 1.0 to 3.0 g / s, more preferably 1.5 to 2.5 g / s. The inner diameter of the tip of the nozzle discharging the hard coat layer-forming composition is preferably φ1.0 to 3.0 mm, more preferably φ1.5 to 2.5 mm. The nozzle movement speed can be appropriately adjusted, but is preferably 2.0 to 8.0 mm / s, more preferably 3.0 to 6.0 mm / s, and even more preferably 4.0 to 5.0 mm / s. The time for discharging the composition for forming a hard coat layer can be adjusted as appropriate, but is preferably 1.0 to 3.0 seconds, more preferably 1.5 to 2.5 seconds. The discharging speed and the moving speed may be constant or may change during the movement, but are preferably constant.

[0015] The first position is a position between a position that is 15.0% of the radius of the lens substrate from the center of the lens substrate and the center of the lens substrate. The first position may be the center of the lens substrate, or a position that is 15.0% of the radius of the lens substrate from the center of the lens substrate. For example, if the radius of the lens substrate is 40 mm, the first position is located at a position that is 0 to 6 mm from the center of the lens substrate. In terms of achieving better effects of the present disclosure, the first position is preferably located between a position that is 3.0% of the radius of the lens substrate from the center of the lens substrate and a position that is 7.0% of the radius of the lens substrate from the center of the lens substrate.

[0016] The second position is a position between a position 15.0% of the radius of the lens substrate from the center of the lens substrate and a position 25.0% of the radius of the lens substrate from the center of the lens substrate. The second position may be a position 15.0% of the radius of the lens substrate from the center of the lens substrate, or a position 25.0% of the radius of the lens substrate from the center of the lens substrate. For example, if the radius of the lens substrate is 40 mm, the second position is located 6 to 10 mm from the center of the lens substrate. The second position is located on either side of the first position and the center of the lens substrate. In other words, the first position, the center of the lens substrate, and the second position are located in this order on a line passing through the center of the lens substrate. The second position is preferably a position between a position that is 17.0% of the radius of the lens substrate from the center of the lens substrate and a position that is 23.0% of the radius of the lens substrate from the center of the lens substrate, and more preferably a position between a position that is 18.0% of the radius of the lens substrate from the center of the lens substrate and a position that is 22.0% of the radius of the lens substrate from the center of the lens substrate, in terms of the effects of the present disclosure being more excellent.

[0017] The method for manufacturing a lens according to the present disclosure will be described below in accordance with the embodiment shown in Figures 1 and 2. Figure 1 is a schematic cross-sectional view of the main parts of the spin coating method according to the embodiment of the present disclosure, and Figure 2 is a view showing the positional relationship of the spin coating method according to the embodiment of the present disclosure from the direction of the white arrow in Figure 1.

[0018] As shown in FIG. 1 , while the lens substrate 10 is rotating, the nozzle 20 located at a first position begins to discharge the hard coat layer-forming composition. In FIG. 1 , the dashed line indicates the rotation axis of the lens substrate 10, which passes through the center of the lens substrate 10. Note that FIG. 1 illustrates an embodiment in which the surface of the lens substrate 10 facing the nozzle 20 is convex and the opposite surface is concave. However, the shape of the lens substrate 10 is not limited to this; each surface may be convex, concave, or flat. In the lens manufacturing method of the present disclosure, while the lens substrate 10 is rotating, the nozzle 20 discharging the hard coat layer-forming composition is moved linearly from the first position through the center of the lens substrate 10 to a second position, as indicated by the black arrow in FIG. 1 . When the nozzle 20 reaches the second position, it stops discharging the hard coat layer-forming composition. At this time, the amount of the composition for forming a hard coat layer discharged from the nozzle 20 at the first position until the nozzle 20 moves to the second position and finishes discharging the composition for forming a hard coat layer is 0.0007 g / mm with respect to the projected area of ​​the lens substrate 10 projected in the direction of the optical axis of the lens substrate 10. ２ The discharge speed of the hard coat layer forming composition and the movement speed of the nozzle 20 are controlled so as to achieve the above.

[0019] As shown in FIG. 2 , the second position P2 is located on the opposite side of the center O of the lens substrate 10 from the first position P1. In other words, the first position P1, the center O of the lens substrate 10, and the second position P2 are located on the same straight line, in that order. In FIG. 2 , the dashed line represents a line passing through the center O of the lens substrate 10, and as described above, the first position P1 and the second position P2 are located on this line. The nozzle 20 moves linearly along this dashed line. In FIG. 2 , on the line passing through the center O of the lens substrate 10, the center O of the lens substrate 10 is represented as a position 0.0% away from the center O of the lens substrate 10, one end of the lens substrate 10 is represented as a position 100.0% away from the center O of the lens substrate 10, and the other end of the lens substrate 10 is represented as a position −100.0% away from the center O of the lens substrate 10. The absolute values ​​of the percentages above are the absolute values ​​of the percentage of the distance from the center of the lens substrate 10 relative to the radius of the lens substrate 10. For example, a position on the above line that is located on the 100.0% side of the center O of the lens substrate 10 and that is 10.0% of the radius of the lens substrate 10 from the center O of the lens substrate 10 is a position of 10.0% from the center O of the lens substrate 10. Furthermore, a position on the above line that is located on the −100.0% side of the center O of the lens substrate 10 and that is 10.0% of the radius of the lens substrate 10 from the center O of the lens substrate 10 is a position of −10.0% from the center O of the lens substrate 10. The first position P1 is located on a line from the center O of the lens substrate 10 to a position that is 15.0% of the radius of the lens substrate 10 from the center O of the lens substrate 10. That is, in FIG. 2 , the first position P1 is a position that is 0.0 to −15.0% from the center O of the lens substrate 10. Note that FIG. 2 shows an embodiment in which the first position P1 and the center O of the lens substrate 10 do not coincide, but the first position P1 may coincide with the center O of the lens substrate 10. The second position P2 is located on a straight line between a position that is 15.0% of the radius of the lens substrate 10 from the center O of the lens substrate 10 and a position that is 25.0% of the radius of the lens substrate 10 from the center O of the lens substrate 10. In other words, in Figure 2, the second position P2 is a position between 15.0 and 25.0% from the center O of the lens substrate 10.

[0020] The thickness of the hard coat layer formed by the lens manufacturing method of the present disclosure is not particularly limited, but is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. The upper limit of the thickness can be, for example, 30 μm or less. The above thickness is an average thickness, and is measured by measuring the thickness at any five points on the hard coat layer and calculating the arithmetic average.

[0021] After the composition for forming a hard coat layer is applied by spin coating, predetermined treatments such as drying and curing may be carried out as necessary to form a hard coat layer.

[0022] The drying treatment is not particularly limited as long as it is a method that removes the solvent contained in the composition for forming a hard coat layer, and may be, for example, natural drying, a method of blowing dry air, or heat drying.

[0023] The content of the curing treatment can be appropriately selected depending on the components contained in the composition for forming a hard coat layer, and examples thereof include a heat treatment and a light irradiation treatment. The temperature in the heat treatment may be any temperature that does not deform the lens substrate, and may be, for example, 30 to 100°C. The drying time may be, for example, 1 to 360 minutes. The light used in the light irradiation treatment is not particularly limited, and examples thereof include ultraviolet light and visible light. The light source may be a high-pressure mercury lamp. The integrated light amount in the light irradiation treatment is not particularly limited, and may be, for example, 100 to 3000 mJ / cm. ２ is preferred, and 100 to 1500 mJ / cm ２ The above-mentioned curing treatment may be carried out simultaneously with the drying treatment, or the drying treatment may also serve as the curing treatment.

[0024] [Other Steps] The method for producing a lens according to the present disclosure may include other steps as long as it includes the step of forming the above-described composition for forming a hard coat layer by a predetermined spin coating method.

[0025] The manufacturing method of the lens of the present disclosure may include a step of forming other layers on the hard coat layer. Examples of other layers include an anti-reflection layer, a water-repellent layer, an anti-fouling layer, and an anti-fogging layer. Known methods can be used to form the other layers.

[0026] The manufacturing method of the lens of the present disclosure may include other steps before forming the hard coat layer. Examples of such other steps include a prewetting step. The prewetting treatment is not particularly limited as long as it can form a coating film on the substrate surface using a prewetting liquid. Examples of prewetting treatment methods include dipping coating, spin coating, spray coating, inkjet coating, and flow coating, with spin coating being preferred for achieving a more uniform prewetting treatment. Known organic solvents can be used as the prewetting liquid. Examples of the organic solvent include alcohol solvents, ether solvents, and ester solvents, with alcohol solvents being preferred.

[0027] The method for manufacturing a lens according to the present disclosure may include a step of forming the lens substrate having the configuration described below. Specifically, the method may include a step of forming another layer, such as a primer layer, on the lens.

[0028] The spin coating device used in the manufacturing method of the lens of the present disclosure is not particularly limited as long as it has a base that can fix and rotate the lens substrate, and a nozzle that can eject the composition for forming a hard coat layer while moving in a predetermined direction, and any known spin coating device can be used.

[0029] Hereinafter, the members (lens substrate and hard coat layer-forming composition) used in the lens manufacturing method of the present disclosure will be described in detail.

[0030] <Lens substrate> The type of lens substrate is not particularly limited, but is preferably a lens for spectacles. For example, when the lens is for spectacles, examples include a finished lens in which both the convex and concave surfaces are optically finished and molded according to a desired power, a semi-finished lens in which only the convex surface is finished as an optical surface (spherical, rotationally symmetric aspherical, progressive surface, etc.), and a semi-finished lens in which the concave surface is processed and polished according to a wearer's prescription.

[0031] The material of the lens substrate is not particularly limited, and examples thereof include glass lenses and plastic lenses, with plastic lenses being preferred. Examples of glass lenses include inorganic glass lenses. The type of plastic (so-called resin) contained in the plastic lens is not particularly limited, and examples thereof include (meth)acrylic acid ester resins, thiourethane resins, allyl resins, episulfide resins, polycarbonate resins, urethane resins, polyester resins, polystyrene resins, polyethersulfone resins, poly-4-methylpentene-1 resins, and diethylene glycol bisallyl carbonate resins (CR-39). Of these, thiourethane resins, episulfide resins, and diethylene glycol bisallyl carbonate resins are preferred. Thiourethane resins are obtained from polyisocyanate compounds and polythiol compounds. As the polyisocyanate compound, it is preferable to use at least one selected from m-xylylene diisocyanate, a mixture of 2,5-bis(isocyanatomethyl)-bicyclo[2,2,1]heptane and 2,6-bis(isocyanatomethyl)-bicyclo[2,2,1]-heptane, isophorone diisocyanate, hexamethylene diisocyanate, and tolylene diisocyanate. As the polythiol compound, it is preferable to use at least one selected from pentaerythritol tetrakis(3-mercaptopropionate), 1,2-bis[(2-mercaptoethyl)thio]-3-mercaptopropane, and a mixture of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane. The episulfide resin is obtained by ring-opening polymerization of a monomer having an episulfide group (also referred to as an epithio group) or a mixed monomer containing this monomer. As the monomer having an episulfide group, it is preferable to use at least one selected from bis(2,3-epithiopropyl) sulfide and bis(2,3-epithiopropyl) disulfide.

[0032] The lens substrate preferably has light-transmitting properties and may be either transparent or opaque. The lens may also be colored.

[0033] The lens substrate may contain additives such as bluing agents, light stabilizers, UV absorbers, and antioxidants.

[0034] The lens substrate may include layers other than lenses such as plastic lenses and glass lenses. For example, the lens substrate may be a plastic lens substrate having another layer formed on the surface thereof. Such another layer may include a primer layer.

[0035] The primer layer can improve the adhesion of the hard coat layer formed by the process described in the present disclosure to the lens and impart impact resistance to the resulting lens. The primer layer may be formed on only one side of the plastic lens, or on both sides of the plastic lens.

[0036] The material constituting the primer layer is not particularly limited, and known materials can be used, for example, resins are mainly used. The type of resin used is not particularly limited, and examples thereof include polyurethane resins, polyester resins, and polyvinyl alcohol, with polyurethane resins being preferred.

[0037] The primer layer may contain components other than the resin, such as fine particles of an oxide of at least one metal selected from Si, Al, Sn, Sb, Ta, Ce, La, Fe, Zn, W, Zr, In, and Ti, or fine particles of a composite oxide thereof, a hydrolyzable silicon compound and / or its hydrolysis condensate, and a surfactant.

[0038] The method for forming the primer layer is not particularly limited, and known methods can be used. For example, a method can be used in which a primer layer-forming composition containing a predetermined resin is applied to a plastic lens, and a curing treatment is performed as necessary to form a primer layer. The method for applying the primer layer-forming composition is not particularly limited, and examples include dipping coating, spin coating, spray coating, inkjet coating, and flow coating. Alternatively, a method can be used in which the hard coat layer-forming composition of the present invention is applied to a substrate. The thickness of the primer layer is not particularly limited, but a thickness of 0.3 to 2 μm is preferred.

[0039] The thickness of the lens substrate is not particularly limited, but from the viewpoint of ease of handling, it is often about 1 to 30 mm. If the lens has a thickness distribution, it is preferable that the central thickness falls within the above range. The size (diameter) of the lens is also not particularly limited, but is often 1 to 200 mm. If the lens is for spectacles, the lens size is often 50 to 100 mm. The refractive index of the lens substrate is not particularly limited, but is often 1.50 or higher, preferably 1.60 to 1.80, and more preferably 1.60 to 1.74.

[0040] <Hard Coat Layer-Forming Composition> The hard coat layer-forming composition contains components capable of forming a hard coat layer. The hard coat layer-forming composition preferably contains components that form a hard coat layer and a solvent.

[0041] The composition for forming a hard coat layer preferably contains a silsesquioxane compound. A silsesquioxane compound is generally a silane compound having a basic skeleton represented by formula (D) obtained by hydrolyzing a trifunctional silane compound such as an alkoxysilane, a chlorosilane, or a silanol. Known structures of silsesquioxane compounds include an irregular form called a random structure, a ladder structure, a cage structure (fully condensed cage structure), and an incomplete cage structure (a partially cleaved cage structure in which some silicon atoms are missing from the cage structure or in which some silicon-oxygen bonds in the cage structure are cleaved). In the following formula (D), R ｄ represents an organic group. ｄ -SiO ３／２ The structure of the silsesquioxane compound contained in the composition for forming a hard coat layer may be any of the above-mentioned random structure, ladder structure, cage structure, and incomplete cage structure, or may be a mixture of multiple types of structures.

[0042] The silsesquioxane compound preferably has a polymerizable group, which is preferably a radically polymerizable group or a cationically polymerizable group.

[0043] The radical polymerizable group contained in the silsesquioxane compound is preferably a group having an ethylenically unsaturated bond. Examples of groups having an ethylenically unsaturated bond include a (meth)acryloyl group, a styryl group, and a vinyl group. When the silsesquioxane compound contains a radical polymerizable group, the equivalent weight of the radical polymerizable group contained in the silsesquioxane compound is not particularly limited, but is preferably 30 to 500 g / eq., and more preferably 30 to 150 g / eq., in terms of achieving superior hardness of the hard coat layer. The silsesquioxane compound having a radical polymerizable group may be synthesized by a known method, or a commercially available product may be used.

[0044] The cationically polymerizable group contained in the silsesquioxane compound is not particularly limited, but examples thereof include an oxetanyl group and an epoxy group.

[0045] The oxetanyl group is a group represented by the following formula (2): ２ represents a hydrogen atom or an alkyl group (for example, a methyl group, an ethyl group, or a propyl group). * represents a bonding position.

[0046]

[0047] The epoxy group is a group represented by the following formula (3): １ represents a hydrogen atom or an alkyl group (for example, a methyl group, an ethyl group, or a propyl group). * represents a bonding position.

[0048]

[0049] The specific silsesquioxane may be synthesized by a known method, or a commercially available product may be used, such as OX-SQ TX-100, OX-SQ SI-20, OX-SQ HDX, and OX-SQ ME-20, manufactured by Toagosei Co., Ltd.

[0050] The content of the silsesquioxane compound having a polymerizable group in the composition for forming a hard coat layer is not particularly limited, but is preferably 10 to 60 mass %, more preferably 20 to 55 mass %, based on the total solid content in the composition for forming a hard coat layer.

[0051] The hard coat layer-forming composition may contain metal oxide particles. The type of metal oxide particles is not particularly limited, and known metal oxide particles may be used. Examples of metal oxide particles include particles of at least one metal oxide selected from Si, Al, Sn, Sb, Ta, Ce, La, Fe, Zn, W, Zr, In, and Ti. Among these, from the viewpoint of ease of handling, metal oxide particles are preferably Si-containing oxide particles (silicon oxide particles), Sn-containing oxide particles (tin oxide particles), Zr-containing oxide particles (zirconium oxide particles), or Ti-containing oxide particles (titanium oxide particles). The metal oxide particles may contain only one of the above-mentioned metals (metal atoms) or two or more metals (metal atoms). Although Si (silicon) is sometimes classified as a semimetal, this specification defines Si as a metal.

[0052] The average particle size of the metal oxide particles is not particularly limited, but is preferably 1 to 200 nm, and more preferably 5 to 30 nm. Within this range, the dispersion stability of the metal oxide particles in the composition for forming a hard coat layer is superior, and whitening of the cured product can be further suppressed. The average particle size is determined by measuring the diameters of 100 or more metal oxide particles using a transmission electron microscope and calculating the arithmetic average. When the metal oxide particles are not perfectly circular, the major axis is used as the diameter.

[0053] Various functional groups may be introduced onto the surface of the metal oxide particles as needed.

[0054] The content of the metal oxide particles in the composition for forming a hard coat layer is not particularly limited, but is preferably 10 to 70 mass %, more preferably 25 to 55 mass %, based on the total solid content in the composition for forming a hard coat layer.

[0055] The hard coat layer-forming composition may contain a polymerizable monomer. The silsesquioxane compound having a polymerizable group is not included in the polymerizable monomer. The polymerizable monomer refers to a compound having a polymerizable group. Examples of the polymerizable monomer include a compound having a radical polymerizable group and a compound having a cationically polymerizable group. The number of polymerizable groups in the polymerizable monomer is preferably 2 to 6, and more preferably 2 to 3.

[0056] The compound having the radical polymerizable group is preferably a (meth)acrylate compound. The term "(meth)acrylate compound" refers to a concept that includes a compound containing a methacryloyl group and a compound containing an acryloyl group. The (meth)acrylate compound is preferably a polyfunctional (meth)acrylate compound having two or more radical polymerizable groups (methacryloyl groups or acryloyl groups) in the molecule, and the preferred number of polymerizable groups is as described above. The (meth)acrylate compound may also be a compound having a group selected from the group consisting of a phosphate group and a sulfonic acid group.

[0057] The polyfunctional (meth)acrylate is preferably a compound represented by formula (E): ２ =CR ｅ１ -CO-L ｅ１ -CO-CR ｅ２ =CH ２ R ｅ１ and R ｅ２ each independently represents a hydrogen atom or a methyl group. ｅ１ represents a divalent hydrocarbon group which may contain a heteroatom (for example, an oxygen atom, a nitrogen atom, or a sulfur atom). The number of carbon atoms in the divalent hydrocarbon group is not particularly limited, and is preferably 1 to 10. Examples of the divalent hydrocarbon group include alkylene groups, alkenylene groups, alkynylene groups, and arylene groups which may contain a heteroatom, and combinations of these groups, and alkylene groups which may contain a heteroatom are preferred. Among these, alkylene groups containing an oxygen atom are preferred, and -O-(L ｅ２ -O) ｒ A group represented by - is preferred.ｅ２ represents an alkylene group (preferably having 1 to 3 carbon atoms), and r represents an integer of 1 or more, preferably an integer of 1 to 10, and more preferably an integer of 2 to 5.

[0058] The (meth)acrylate compounds may be used alone or in combination of two or more.

[0059] The compound having the cationically polymerizable group is preferably an epoxy compound having an epoxy group. The epoxy group is a group represented by the above formula (3). The epoxy compound is preferably a multifunctional epoxy compound having two or more epoxy groups in the molecule, and the preferred number of polymerizable groups is as described above. The type of multifunctional epoxy compound is not particularly limited, and known multifunctional epoxy compounds can be used. Examples of multifunctional epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, phenol novolac type epoxy compounds, cresol novolac type epoxy compounds, and aliphatic glycidyl ether type epoxy compounds.

[0060] The epoxy compounds may be used alone or in combination of two or more.

[0061] The composition for forming a hard coat layer may contain at least one selected from the group consisting of hydrolyzable silicon compounds, their hydrolysates, and their hydrolysis condensates (hereinafter, also simply referred to as "hydrolyzable silicon compounds"). The hydrolyzable silicon compound refers to a compound in which a hydrolyzable group is bonded to a silicon atom. The hydrolyzable silicon compound is preferably a compound represented by formula (H). Formula (H) R ｈ１ -L ｈ -Si(R ｈ２ ) ｓ (R ｈ３ ) ３－ｓ R ｈ１ represents an epoxy group. The definition of the epoxy group is as described above.

[0062] L ｈrepresents a divalent hydrocarbon group which may contain a heteroatom. The number of carbon atoms in the hydrocarbon group is not particularly limited, and is preferably 1 to 10. Examples of the divalent hydrocarbon group include an alkylene group, an alkenylene group, an alkynylene group, an arylene group, and combinations of these groups, and an alkylene group which may contain a heteroatom is preferred.

[0063] R ｈ２ represents a hydrolyzable group. The hydrolyzable group is a group that is directly bonded to Si (silicon atom) and can undergo a hydrolysis reaction and / or a condensation reaction. Examples of the hydrolyzable group include an alkoxy group, a hydroxyl group, a halogen atom, an acyloxy group, an alkenyloxy group, and an isocyanate group. R ｈ３ represents an alkyl group. ｈ３ The number of carbon atoms in the alkyl group represented by the formula (I) is preferably 1 to 10. s represents an integer of 1 to 3. s is preferably 3.

[0064] The hydrolyzate of a hydrolyzable silicon compound refers to a compound obtained by hydrolyzing the hydrolyzable groups in the hydrolyzable silicon compound.The hydrolyzate may be one in which all of the hydrolyzable groups are hydrolyzed (complete hydrolyzate), or one in which only a portion of the hydrolyzable groups are hydrolyzed (partial hydrolyzate).In other words, the hydrolyzate may be a complete hydrolyzate, a partial hydrolyzate, or a mixture thereof.

[0065] Furthermore, the hydrolysis condensate of hydrolyzable silicon compound refers to a compound obtained by hydrolyzing the hydrolyzable group in the hydrolyzable silicon compound and condensing the obtained hydrolyzate.The above-mentioned hydrolysis condensate may be a compound in which all hydrolyzable groups are hydrolyzed and all the hydrolyzate is condensed (complete hydrolysis condensate), or a compound in which some of the hydrolyzable groups are hydrolyzed and some of the hydrolyzate is condensed (partial hydrolysis condensate).In other words, the above-mentioned hydrolysis condensate may be a complete hydrolysis condensate, a partial hydrolysis condensate, or a mixture thereof.

[0066] When the composition for forming a hard coat layer contains hydrolyzable silicon compounds, the content of the hydrolyzable silicon compounds is not particularly limited, but is preferably 0.5 to 30 mass %, more preferably 1 to 10 mass %, based on the total solid content in the composition for forming a hard coat layer.

[0067] The hard coat layer-forming composition may contain a radical polymerization initiator. Examples of the radical polymerization initiator include a photoradical polymerization initiator and a thermal radical polymerization initiator. The hard coat layer-forming composition may contain a cationic polymerization initiator. Examples of the cationic polymerization initiator include a photocationic polymerization initiator and a thermal cationic polymerization initiator.

[0068] The composition for forming a hard coat layer may contain various additives, such as an ultraviolet absorber, a surfactant, an antiaging agent, a coating film modifier, a light stabilizer, an antioxidant, a coloring inhibitor, a dye, a filler, and an internal mold release agent, as needed.

[0069] The composition for forming a hard coat layer preferably contains a solvent in terms of dischargeability and coverage in a spin coating method. The solvent is not particularly limited and may be water or an organic solvent. Examples of organic solvents include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, hydrocarbon-based solvents, halogenated hydrocarbon-based solvents, amide-based solvents, sulfone-based solvents, and sulfoxide-based solvents. Alcohol-based solvents having 10 or fewer carbon atoms are preferred, and alcohol-based solvents having 5 or fewer carbon atoms (e.g., isopropanol) are more preferred. The alcohol-based solvent may also be a polyhydric alcohol having two or more hydroxy groups in one molecule. The solvent may be used alone or in combination of two or more.

[0070] The content of the total solid content in the composition for forming a hard coat layer is preferably 10 to 90 mass %, more preferably 40 to 80 mass %, based on the total mass of the composition for forming a hard coat layer.

[0071] The viscosity of the hard coat layer-forming composition at 25°C is preferably 10 mPa·s or more, more preferably 13 mPa·s or more, and even more preferably 15 mPa·s or more, from the viewpoint of film thickness. The upper limit of the viscosity of the hard coat layer-forming composition at 25°C is preferably 25 mPa·s or less, more preferably 20 mPa·s or less, from the viewpoint of coating properties. According to the lens manufacturing method of the present disclosure, a hard coat layer with few defects can be formed even if the viscosity of the hard coat layer-forming composition at 25°C is 10 mPa·s or more. The viscosity can be measured using a known measuring device (for example, a cone-plate viscometer, etc.).

[0072] The hard coat layer-forming composition may be prepared by mixing the components described above. The mixing method is not particularly limited, and known methods can be used. When the hard coat layer-forming composition contains a silsesquioxane having a cationically polymerizable group and metal oxide particles, it is preferable to obtain the hard coat layer-forming composition by the following procedure in order to suppress changes in viscosity over time during storage. First, in step A, a mixture containing a silsesquioxane having a cationically polymerizable group and metal oxide particles is heat-treated at a temperature above 60°C. Next, in step B, the mixture obtained in step A is mixed with a cationic polymerization initiator to obtain a hard coat layer-forming composition. The heating temperature of the mixture in step A is preferably 60°C, more preferably 80°C or higher, even more preferably 100°C or higher, particularly preferably 120°C or higher, and most preferably 140°C or higher. The upper limit of the heating temperature is not particularly limited, and is preferably 200°C or lower. The heating temperature refers to the set temperature of a heating device (such as a hot plate) used to heat the mixture.

[0073] <Lens> Lenses obtained by the lens manufacturing method of the present disclosure will now be described. FIG. 3 is an example of a lens obtained by the lens manufacturing method of the present disclosure. The lens 40 shown in FIG. 3 has a plastic lens 30, a primer layer 32, a hard coat layer 34, an anti-reflection film 36, and a water- and oil-repellent layer 38, in this order. In the lens 40 shown in FIG. 3, the primer layer 32, the hard coat layer 34, the anti-reflection film 36, and the water- and oil-repellent layer 38 are formed, in this order, on one side of the plastic lens 30. However, in FIG. 3, the primer layer, the hard coat layer, the anti-reflection film, and the water- and oil-repellent layer may be formed, in this order, on the surface of the plastic lens 30 opposite the primer layer 32 side. Furthermore, in the lens 40 shown in FIG. 3, any one or more of the primer layer 32, the anti-reflection film 36, and the water- and oil-repellent layer 38 may be omitted. The plastic lens 30, the primer layer 32, and the hard coat layer 34 are as described above, and preferred embodiments are also as described above. The following describes the anti-reflection coating and water- and oil-repellent layer that may be included in the lens obtained by the lens manufacturing method of the present disclosure (hereinafter also simply referred to as the "obtained lens").

[0074] [Anti-reflection film] The obtained lens may have an anti-reflection film. The anti-reflection film is preferably disposed on the side of the hard coat layer opposite the plastic lens. The anti-reflection film is a layer that has the function of preventing reflection of incident light. Specifically, the anti-reflection film can have low reflectance characteristics (broadband low reflectance characteristics) over the entire visible range of 380 to 780 nm.

[0075] The structure of the antireflective film is not particularly limited, and may be a single-layer structure or a multilayer structure. An inorganic antireflective film is preferred as the antireflective film. An inorganic antireflective film is an antireflective film composed of an inorganic compound. In the case of a multilayer structure, a structure in which low-refractive-index layers and high-refractive-index layers are alternately stacked is preferred. Examples of materials constituting the high-refractive-index layers include oxides of titanium, zirconium, aluminum, niobium, tantalum, or lanthanum. Examples of materials constituting the low-refractive-index layers include oxides of silica. The method for producing the antireflective film is not particularly limited, and examples include dry methods such as vacuum deposition, sputtering, ion plating, ion-beam assisted deposition, and CVD.

[0076] [Water- and oil-repellent layer] The resulting lens may include a water- and oil-repellent layer. The water- and oil-repellent layer is preferably disposed as the outermost layer of the lens. The water- and oil-repellent layer reduces the surface energy of the lens, improving the lens's anti-contamination function and improving the lubricity of the lens surface, thereby improving the lens's abrasion resistance. The water- and oil-repellent layer is preferably provided when the resulting lens is a lens for glasses.

[0077] The material constituting the water- and oil-repellent layer is not particularly limited, and examples thereof include fluorine-containing compounds (compounds containing fluorine atoms) and silicon-containing compounds (compounds containing silicon atoms). Among these, the water- and oil-repellent layer preferably contains a fluorine-containing compound, and more preferably contains at least one selected from the group consisting of fluorine-substituted alkyl group-containing organosilicon compounds, their hydrolysates, and their hydrolyzed condensates. The material constituting the water- and oil-repellent layer may be used alone or in combination of two or more.

[0078] The organosilicon compound containing fluorine-substituted alkyl group is the organosilicon compound that contains alkyl group in which part or all of hydrogen atom is replaced by fluorine atom, and has hydrolyzable group.Here, the hydrolyzable group is the group that is directly bonded to silicon atom and can proceed hydrolysis reaction and condensation reaction, for example, alkoxy group, halogen atom, acyloxy group, alkenyloxy group and isocyanate group.It should be noted that when a plurality of hydrolyzable groups are directly bonded to one silicon atom, they can be the same or different.

[0079] The hydrolyzate of a fluorine-substituted alkyl group-containing organosilicon compound refers to a compound obtained by hydrolyzing the hydrolyzable groups in a fluorine-substituted alkyl group-containing organosilicon compound. The hydrolyzate may be one in which all of the hydrolyzable groups are hydrolyzed (complete hydrolyzate) or one in which only a portion of the hydrolyzable groups are hydrolyzed (partial hydrolyzate). In other words, the hydrolyzate may be a complete hydrolyzate, a partial hydrolyzate, or a mixture thereof. The hydrolyzed condensate of a fluorine-substituted alkyl group-containing organosilicon compound refers to a compound obtained by hydrolyzing the hydrolyzable groups in a fluorine-substituted alkyl group-containing organosilicon compound and condensing the resulting hydrolyzate. The hydrolyzed condensate may be one in which all of the hydrolyzable groups are hydrolyzed and the hydrolyzate is completely condensed (complete hydrolyzed condensate), or one in which only a portion of the hydrolyzable groups are hydrolyzed and a portion of the hydrolyzate is condensed (partial hydrolyzed condensate). In other words, the hydrolyzed condensate may be a complete hydrolyzed condensate, a partial hydrolyzed condensate, or a mixture thereof.

[0080] There are no particular restrictions on the thickness of the water- and oil-repellent layer of the resulting lens, but it is preferably 5 to 35 nm.

[0081] The method for forming the water- and oil-repellent layer is not particularly limited and can be selected as desired depending on the materials used, the desired performance, thickness, etc. Examples include a method in which a water- and oil-repellent layer-forming composition containing a fluorine-substituted alkyl group-containing organosilicon compound is applied to a substrate and cured as needed, and a dry method. Coating methods include, for example, dip coating, roll coating, bar coating, spin coating, spray coating, die coating, and gravure coating. Curing treatments include, for example, light irradiation treatment, heat treatment, and water vapor contact treatment. Water vapor contact treatments include, for example, contact with air controlled at a humidity of 50 to 90% RH. The above curing treatments may be performed in combination. Examples of dry methods include the same methods as those used for the antireflective coating described above.

[0082] <Uses> Lenses obtained by the lens manufacturing method of the present disclosure are suitable for use in various lens applications, and are particularly suitable for use as lenses for eyeglasses.

[0083] The present disclosure will be explained in more detail below using examples, but the present disclosure is not limited to these examples in any way.

[0084] [Preparation of Hard Coat Layer-Forming Composition] To a glass container equipped with a stirrer, (A) a cationically curable silsesquioxane (manufactured by Toagosei Co., Ltd.: OX-SQ TX-100) (27.13 g) as the silsesquioxane, and (B) colloidal silica (manufactured by JGC Catalysts and Chemicals Co., Ltd.: OSCAL-1432E, isopropanol dispersion, solids content 30% by mass) (90.45 g) as the metal oxide particles were added to form a mixture. The resulting mixture was stirred for 6 hours while being heated on a hot plate set to 160°C. At this time, the glass container was sealed with a lid, and the solvent in the mixture was in a reflux state.

[0085] After heating, the resulting reaction solution was cooled to room temperature overnight, and then 2-butoxyethanol (10.85 g) was added to the cooled reaction solution as a membrane-forming solvent. Next, isopropanol was distilled off from the reaction solution under reduced pressure at 40°C over 2 hours. Methanol (33.40 g) was added to the resulting crude product to obtain Liquid Composition X1.

[0086] In a glass container equipped with a stirrer, the liquid composition X1 (98.52 g) obtained in the above step 1, (D) SbF as a cationic polymerization initiator, and ６ － A hard coat layer-forming composition was obtained by adding and mixing a hydroxyphenyltriazine-based sulfonium salt (San-Aid SI-150L manufactured by Sanshin Chemical Industry Co., Ltd.) (0.52 g) as an (F) ultraviolet absorber, a hydroxyphenyltriazine-based ultraviolet absorber (Tinuvin 477 manufactured by BASF Japan Ltd.) (0.62 g) as an ultraviolet absorber, and a polyether-modified silicone (DOWSIL L-7001 manufactured by Dow Corning Toray Co., Ltd.) (0.33 g) as an (G) surfactant. The viscosity of the hard coat layer-forming composition at 25°C was 16.8 mPa s.

[0087] [Preparation of primer layer-forming composition] Pure water (179 parts by mass) and surfactants 501W ADDITIVE (manufactured by Dow Chemical) (1.1 parts by mass) and L7001 (manufactured by Dow Chemical) (1.1 parts by mass) were added to an aqueous urethane dispersion (Evafal HA170, manufactured by Nicca Chemical Co., Ltd., solids concentration 37% by mass) (200 parts by mass), and the mixture was stirred to obtain a primer layer-forming composition with a solids concentration of 20.0% by mass.

[0088] [Formation of Primer Layer] First, a lens with a refractive index of 1.60 (Nikon Lite AS Material S-3.00D, manufactured by Nikon Essilor Corporation) was prepared as a plastic lens. The diameter of the plastic lens was 80 mm. The substrate was placed on a spin coater, and the substrate was rotated at 500 rpm for 2 seconds. During this rotation, 2.5 mL of a primer layer-forming composition was dripped from the outer periphery of the substrate to the center. The substrate onto which the primer layer-forming composition had been dripped was then accelerated to 600 rpm in 10 seconds, after which it was rotated for 5 seconds, and further accelerated to 2000 rpm, after which it was rotated for 3 seconds, thereby performing a primer treatment. By performing the primer treatment, a coating film of the primer layer-forming composition was formed on the substrate. This resulted in a lens substrate. The projection of the lens substrate from the optical axis direction of the lens substrate was a circle with a diameter of 80 mm.

[0089] [Prewetting Treatment] A prewetting treatment was performed on the substrate on which the primer layer was formed by the above procedure. A mixed solvent of 75% by mass of methanol and 25% by mass of 2-butoxyethanol was used as the prewetting liquid. First, the substrate was placed on a spin coater, and the substrate was rotated at 300 rpm for 2 seconds. During this rotation, 4 mL of the prewetting liquid was dripped from the center to the outer periphery of the substrate. Then, the substrate on which the prewetting liquid had been dripped was rotated at 1000 rpm for 1 second to perform the prewetting treatment. By performing the prewetting treatment, a coating film made of the prewetting liquid was formed on the substrate. The temperature of the substrate immediately before the prewetting treatment was adjusted to 30 to 40°C.

[0090] [Formation of hard coat layer] The above-mentioned hard coat layer-forming composition was applied to the surface of the substrate on which the prewet treatment was performed as described above to form a coating film of the prewet liquid by spin coating under the conditions shown below, thereby forming a coating film of the hard coat layer-forming composition. The substrate was rotated at 300 rpm and moved over 2 seconds from the predetermined first position shown in the table to the predetermined second position shown in the table, while the above-mentioned hard coat layer-forming composition was ejected in a predetermined amount shown in the table. Furthermore, the substrate onto which the hard coat layer-forming composition was dropped was rotated at 300 rpm for 15 seconds, furthermore, the speed was increased to 400 rpm in 5 seconds and then rotated for 1 second, furthermore, the speed was increased to 700 rpm in 5 seconds and then rotated for 1 second, furthermore, the speed was increased to 1000 rpm in 5 seconds and then rotated for 1 second, furthermore, the speed was increased to 1500 rpm in 5 seconds and then rotated for 1 second. In the table, the first and second positions represent positions on a line passing through the center of the lens substrate, with the center of the lens substrate at a distance of 0.0% from the center of the lens substrate, one end of the lens substrate at a distance of 100.0% from the center of the lens substrate, and the other end of the lens substrate at a distance of −100.0% from the center of the lens substrate, as shown in Figure 2. For example, if the first position is −10.0% and the second position is 20.0%, the second position is located on the opposite side of the center of the lens substrate from the first position, with the first position being a distance of 4 mm that is 10.0% of the radius of the lens substrate (40 mm) from the center of the lens substrate, and the second position being a distance of 8 mm that is 20.0% of the radius of the lens substrate (40 mm) from the center of the lens substrate. Furthermore, for example, when the first position is 5.0% and the second position is 20.0%, the center of the lens substrate, the first position, and the second position are located on the same straight line in that order, with the first position being a position that is a distance (2 mm) that is 5.0% of the radius (40 mm) of the lens substrate from the center of the lens substrate, and the second position being a position that is a distance (8 mm) that is 20.0% of the radius (40 mm) of the lens substrate from the center of the lens substrate.

[0091] After forming a coating film of the composition for forming a hard coat layer by the above procedure, the substrate was heated at 80°C for 20 minutes and then further heated at 100°C for 1 hour to form a cured film, thereby obtaining lenses of each example and comparative example. The average thickness of the formed cured film was about 15 to 16 μm.

[0092] <Evaluation> [Coating Property] The lenses obtained by the above procedure were checked under fluorescent light to see if a hard coating layer was formed on the entire surface of the lens. If the entire surface of the lens was coated, the coating was excellent and acceptable. If an uncoated area occurred near the center, it was unacceptable. Only lenses that were acceptable in terms of coating property were evaluated for round defects and swirl defects as described below, and lenses that were unacceptable were not evaluated for round defects and swirl defects as described below.

[0093] [Round Defects] The lenses obtained by the above procedure were checked for the presence or absence of round defects under fluorescent lamps and ultra-high pressure mercury lamps, and the difficulty of observing round defects was evaluated according to the following evaluation criteria. In practice, a rating of A to B is preferable. Note that round defects refer to round or point-like defects with a diameter of approximately 1 to 10 mm. A: No round defects are observed under either the ultra-high pressure mercury lamp or the fluorescent lamp. B: Faint round defects are observed only under the ultra-high pressure mercury lamp, and no round defects are observed under the fluorescent lamp. C: Faint round defects and dark round defects are observed under the ultra-high pressure mercury lamp, and pale round defects are observed under the fluorescent lamp, but no dark round defects are observed. D: Faint round defects and dark round defects are observed under both the ultra-high pressure mercury lamp and the fluorescent lamp.

[0094] [Spiral Defects] The lenses obtained by the above procedure were checked for the presence or absence of swirl defects under fluorescent lamps and ultra-high pressure mercury lamps, and the difficulty of observing swirl defects was evaluated according to the following evaluation criteria. In practice, a rating of A to B is preferable. Note that swirl defects refer to swirling, streak-like defects. A: No swirl defects are observed under either the ultra-high pressure mercury lamp or the fluorescent lamp. B: Faint swirl defects are observed only under the ultra-high pressure mercury lamp, and no swirl defects are observed under the fluorescent lamp. C: Faint and dark swirl defects are observed under the ultra-high pressure mercury lamp, and pale swirl defects are observed under the fluorescent lamp, but no dark swirl defects are observed. D: Faint and dark swirl defects are observed under both the ultra-high pressure mercury lamp and the fluorescent lamp.

[0095] [Overall Evaluation] Based on the evaluation results of the coverage and the round and spiral defects, the state of the hard coat layer was evaluated according to the following evaluation criteria. In practice, a rating of A to B is preferable. A: Both round and spiral defects are rated A. B: At least one of the round and spiral defects is rated B, and the other is rated A or B. C: At least one of the round and spiral defects is rated C, and the other is rated A, B, or C. D: At least one of the round and spiral defects is rated D.

[0096] <Results> Tables 1 to 3 show the first and second positions, the discharge amount of the composition for forming a hard coat layer, and the evaluation results for each example and comparative example. Table 1 shows the evaluation results for round defects, Table 2 shows the evaluation results for spiral defects, and Table 3 shows the evaluation results for the overall evaluation. In the tables, the values ​​for the first and second positions are as described above. In the tables, "-" means that evaluation of coverage was not permitted and evaluation of the subject in each table was not performed.

[0097]

[0098]

[0099]

[0100] The evaluation results confirmed that the lens manufacturing method of the present disclosure makes it possible to manufacture lenses having a hard coat layer with excellent coverage and with which round and spiral defects are less likely to be observed. It was confirmed that coverage is poor when the second position is not positioned on either side of the center of the lens substrate from the first position. It was confirmed that round defects are likely to occur when the second position is located at a distance from the center of the lens substrate that is less than 15% of the radius of the lens substrate. The discharge amount of the composition for forming a hard coat layer relative to the projected area of ​​the lens substrate projected from the optical axis direction of the lens substrate is 0.0007 g / mm ２ It has been confirmed that when the thickness is less than 1 / 2 mm, swirl defects tend to occur.

[0101] The results shown in Table 2 confirm that swirl defects are less likely to occur when the first position is a position on a straight line from a position that is 3.0% of the radius of the lens substrate from the center of the lens substrate to a position that is 7.0% of the radius of the lens substrate from the center of the lens substrate.The results shown in Table 2 confirm that swirl defects are less likely to occur when the second position is a position on a straight line from a position that is 17.0% of the radius of the lens substrate from the center of the lens substrate to a position that is 23.0% of the radius of the lens substrate from the center of the lens substrate.

[0102] REFERENCE SIGNS LIST 10 Lens substrate 20 Nozzle 30 Plastic lens 32 Primer layer 34 Hard coat layer 36 Anti-reflection film 38 Water- and oil-repellent layer 40 Lens P1 First position P2 Second position O Center of lens substrate

Claims

1. A method for manufacturing a lens, comprising applying a composition for forming a hard coat layer to a lens substrate by a spin coating method to form a hard coat layer and manufacturing a lens, wherein, in the spin coating method, while rotating the lens substrate, a nozzle for discharging the composition for forming a hard coat layer from its tip is moved linearly from a first position through the center of the lens substrate to a second position located between the first position and the center of the lens substrate while discharging the composition for forming a hard coat layer, and the amount of the composition for forming a hard coat layer discharged relative to the projected area of ​​the lens substrate projected from the optical axis direction of the lens substrate is 0.0007 g / mm ２ the first position is located between a position away from the center of the lens substrate by a distance of 15.0% of a radius of the lens substrate, and the second position is located between a position away from the center of the lens substrate by a distance of 15.0% of the radius of the lens substrate and a position away from the center of the lens substrate by a distance of 25.0% of the radius of the lens substrate.

2. The method of claim 1, wherein the first position is located between a position that is 3.0% of the radius of the lens substrate from the center of the lens substrate and a position that is 7.0% of the radius of the lens substrate from the center of the lens substrate.

3. A method for manufacturing a lens as described in claim 1 or 2, wherein the second position is located between a position that is 17.0% of the radius of the lens substrate from the center of the lens substrate and a position that is 23.0% of the radius of the lens substrate from the center of the lens substrate.

4. The method for producing a lens according to any one of claims 1 to 3, wherein the viscosity of the composition for forming a hard coat layer at 25°C is 10 mPa·s or more.

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