Mold apparatus for manufacturing eyewear lens and related method

Abstract

The present application relates to a mould apparatus (1) configured to manufacture a spectacle lens (7), comprising a plastic mould element (2) and a glass or metal mould element (3). The application further relates to a method configured to manufacture said mould apparatus (1) and to a method configured to manufacture an ophthalmic lens (7) using said mould apparatus (1).

Description

Technical Field

[0001] The present invention relates to a mold device configured to manufacture spectacle lenses, a method configured to manufacture the mold device, and a method configured to manufacture spectacle lenses using the mold device. Background Art

[0002] Various methods are known for the mass production of spectacle lenses, including finished spectacle lenses and semi-finished spectacle blanks (lens blanks; so-called discs). One of the conventional production methods is molding. Depending on the choice of spectacle lens material and the corresponding process, the molding techniques for spectacle lenses can be subdivided into casting molding, injection molding, and other processes such as rubber molding.

[0003] In "casting", hard resin spectacle lenses are typically produced, such as thermosetting plastics, for example allyl diglycol carbonate (e.g., CR39). The monomers of the resin typically exist in the form of a low-viscosity liquid. Then, the casting formulation is introduced into a tool mold or casting mold having, for example, two (glass) mold shells. An elastic spacer ring (washer) is placed between the mold shells. Polymerization is carried out, for example, in a refrigerator / heating cabinet or in a water bath at a temperature between 10°C and 130°C. Such a washer has excellent mechanical load-bearing capacity and allows not only the casting of finished products but also the casting of semi-finished products. For example, in the case where the first surface (e.g., the front surface) has been formed, the second surface (prescription surface; e.g., the back surface) can be manufactured by milling, grinding, and polishing at a subsequent stage as required.

[0004] "Injection molding" is an efficient method for the mass production of plastic finished or semi-finished spectacle lenses. Different from casting, in the case of injection molding, the plastic (polymer) already exists in the form of pellets. Exemplary plastic materials are thermoplastics such as polymethyl methacrylate (PMMA), polycarbonate (PC), polyamide (PA), and polystyrene (PS). The pellets are melted in an injection cylinder, converted into a homogeneous melt, and injected into the corresponding tool mold under high pressure. The tool mold is typically made of steel, iron-nickel alloy, and tungsten alloy. After a short cooling stage, the spectacle lenses molded in this way have sufficient dimensional stability and can be removed from the tool mold.

[0005] Molding (including casting and injection molding processes) is an efficient production technology for manufacturing spectacle lenses with complex and delicate geometries with high precision. Finished spectacle lenses or semi-finished spectacle blanks can be efficiently produced by molding. However, in the case of the stringent requirements and complex characteristics of spectacle lenses, the molding process remains challenging. Most finished or semi-finished spectacle lenses require high optical quality and precisely controlled surface profiles, which require a high degree of control over processing parameters and high-precision optical mold equipment. In the molding of spectacle lenses, various lens materials can be used, including optical materials, glass, thermosetting hard resins, thermoplastic hard resins, photochromic materials, and / or photochromic fatigue as described in DIN EN ISO 13666:2019-12. Preferably, the spectacle lens material can be made of the following materials: thermosetting hard resins according to Section 3.3.3 of DIN EN ISO 13666:2019-12; thermoplastic hard resins according to Section 3.3.4 of DIN EN ISO 13666:2019-12; photochromic materials according to Section 3.3.5 of DIN EN ISO 13666:2019-12; or other suitable resins.

[0006] Especially during the molding process, form deviations of the spectacle lens may be caused by residual stresses generated by molecular orientation and thermal residual stresses caused by shrinkage during the cooling stage. It has been shown that by using appropriate mold equipment, the molded spectacle lens can achieve good control of the surface profile and reduce residual stresses. In this regard, in traditional casting molding, based on the high chemical resistance of glass or metal and the small amount of geometric distortion over time, the mold is typically made of glass or metal. On the other hand, the low distortion of the glass or metal mold and the high shrinkage of the monomer may generate excessive stress between the spectacle lens and the mold surface. This may lead to problems such as premature separation of the spectacle lens during the process, strain of the spectacle lens, and breakage of the mold. Therefore, using a pair of glass or metal molds may not enable the spectacle lens to obtain precise complex characteristics, and the process may be expensive. In addition, cleaning and replicating glass or metal molds may be both laborious and time-consuming. US 2004 / 0207105 A1 recognized the following problem: Lenses made by using a mold assembly in which one or both of the mold parts are made of amorphous materials may have defects such as pits and warping. Apparently, the present invention aims to overcome the problems caused by the use of a thermoplastic amorphous polymer in at least one mold element and to solve this problem by changing the path of the radiation rays reaching the mold element to be cured and controlling the relative intensity of the radiation on a specific part of the lens-forming material. However, this solution requires additional adjustment of the mold element and incorporation of specific diffraction structures, which is obviously both complex and time-consuming.

[0007] WO 2021 / 209497 recognizes the problems of glass molds and chooses to use a molding device in which both mold shells are made of thermoplastic to form spectacle lenses by thermosetting casting technology. Further, to improve the lens quality, WO 2021 / 209497 coats a reverse hard multi-coating stack on the thermoplastic mold shell so that the hard multi-coating stack can be transferred to the surface of the spectacle lens. To solve similar problems caused by using glass molds, WO 2006 / 055815 proposes a disposable mold for forming ophthalmic lenses, which includes a substantially amorphous thermoplastic material forming an optically precise surface with a removable coating on the optically precise surface of the mold. Summary of the Invention

[0008] The present invention relates to a molding device configured to manufacture spectacle lenses, comprising two mold elements, characterized in that one of the two mold elements is a plastic mold element and the other mold element is a glass mold element or a metal mold element. The present invention further relates to related methods, such as related methods for manufacturing the present molding device and related methods for manufacturing spectacle lenses using the present molding device. Brief Description of the Drawings

[0009] Figure 1 Illustrates a molding device according to the present invention and spectacle lenses produced by the molding device.

[0010] Figure 2 is a schematic diagram of an exemplary method according to the present invention, which uses a Figure 1 molding device coated with a mold release agent.

[0011] Figure 3 is a schematic diagram of an exemplary method according to the present invention, which uses a Figure 1 molding device produced by injection molding with a mixture of plastic and mold release agent.

[0012] Figure 4 is a schematic diagram of an exemplary method according to the present invention, which uses a Figure 1 molding device produced by casting with a mixture of thermosetting plastic and mold release agent.

[0013] Figure 5 Illustrates a molding device according to the present invention using a supporting mold element. Detailed Description of the Invention

[0014] The inventors of the present invention have found that if both die elements of a molding device are made of a thermoplastic material as selected in the prior art references, the risk of lens distortion during lens production is significantly increased. This is because thermoplastics have low chemical resistance, high geometric distortion, and low heat resistance, and during the thermal curing process, the thermoplastic die may deform due to its poor ability to resist the stress generated by monomer shrinkage. This means that the mechanical properties of the thermoplastic die elements on both sides of the spectacle lens to be produced are weak and prone to deformation, thus unable to produce the desired shape and surface profile of the spectacle lens.

[0015] In addition, for the mold opening process of the mold device after curing, unlike a glass die element or a metal die element that can resist the mold opening force, the deformation of the spectacle lens due to the applied force helps the spectacle lens itself to detach from the glass die element or the metal die element. In the case where both die elements are made of thermoplastic, the increased mold opening force may distort both the thermoplastic die element and the produced spectacle lens, making detachment significantly difficult. Moreover, due to the strong covalent bonding between the spectacle lens material and the thermoplastic die element, the swelling of the thermoplastic die element, and the penetration of the spectacle lens material into the thermoplastic die element, the spectacle lens produced by using two thermoplastic die elements is even more difficult to clean and to be satisfactorily separated from the thermoplastic die element.

[0016] The difficulties described above in terms of mold opening of the mold device and demolding of the produced spectacle lens mean that a significantly greater mold opening force is required, which may cause damage to the produced spectacle lens and the thermoplastic die element, and such damage results in the unacceptability of the spectacle lens and the non-reusability of the thermoplastic die.

[0017] To solve the above problems, according to a first aspect of the present invention, a novel mold device is provided. A mold device configured to manufacture a spectacle lens according to the present invention includes two die elements, characterized in that one of the two die elements is a plastic die element and the other die element is a glass die element or a metal die element.

[0018] Two mold elements of a mold device, together with a device for connecting the two mold elements, define the form of an ophthalmic lens to be produced. The term "ophthalmic lens" is an ophthalmic lens, i.e., a lens intended for measuring, correcting, and / or protecting the eye or changing its appearance, worn in front of the eyeball but not in contact with the eyeball (compare DIN EN ISO 13666:2019, Sections 3.5.1 and 3.5.2). The term "ophthalmic lens" used in the present invention refers to a finished ophthalmic lens as defined by DIN EN ISO 13666:2019 (Section 3.8.1), a semi-finished ophthalmic blank (a lens blank having only one optically finished surface), and a lens blank (a block of material used to manufacture a lens at any stage before the surface processing process is completed, usually a preform).

[0019] "Molding" in the present invention refers to the process of molding an ophthalmic lens material around two mold elements (which are preformed parts) to produce an ophthalmic lens. In the context of the present invention, in addition to "injection molding", the term "molding" refers to the molding process in ophthalmic lens casting, in other words, casting molding.

[0020] In the casting process, the ophthalmic lens material (e.g., resin monomer) is typically prepared in the form of a low-viscosity liquid. The molding formulation (in which the resin monomer exists as a low-viscosity liquid) is introduced into a mold device that includes two mold elements (mold shells) defining the profile of the ophthalmic lens. A device for connecting the two mold elements (such as a gasket, ring, or band) connects the two mold elements, thus creating a cavity corresponding to the shape of the ophthalmic lens to be produced. Then, the molding formulation is filled into the cavity and heat-cured to initiate polymerization. Thereafter, the ophthalmic lens so produced is detached from the mold device.

[0021] Ophthalmic lens material refers to a material suitable for manufacturing an ophthalmic lens, without limitation thereto, as long as the material is suitable for casting. Exemplary ophthalmic lens materials can be thermoplastic or thermosetting plastic materials, preferably thermosetting plastic materials. For example, a polythiourethane resin (MR8) with a refractive index of 1.60, or a polythiourethane resin (MR7, MR10) with a refractive index of 1.67, or an allyl diglycol carbonate resin with a refractive index of 1.499 can be used. A complete set of examples of optical materials suitable for the lens casting process is listed in Table 1.

[0022] Table 1: Examples of Ophthalmic Lens Materials for Casting

[0023]

[0024]

[0025] *Based on sodium D line

[0026] The plastic mold element according to the present invention is a mold element made of plastic. In a preferred embodiment, the plastic can be a thermoplastic material and / or a thermosetting material, transparent or opaque. The term "thermoplastic" refers to any plastic polymer material that becomes moldable at a specific high temperature and solidifies upon cooling. The term "thermosetting plastic" refers to any polymer low-viscosity monomer that becomes insoluble and infusible at a specific high temperature and solidifies upon cooling.

[0027] The thermoplastic can be selected from the group consisting of, but not limited to: polycarbonate, polyamide, polysulfone, polyester, polyetheretherketone (PEEK), polyolefin, cycloolefin copolymer (COC), cycloolefin polymer (COP), and cyclic block copolymer (CBC). Preferably, the thermoplastic is selected from at least one group consisting of: polycarbonate, polyamide, polysulfone, polyester, and polyetheretherketone (PEEK). The thermosetting plastic can be selected from the group consisting of, but not limited to: polythiourethane, polyurethane, methacrylate, polythiirane, and polyallyl diglycol carbonate.

[0028] It is required that the surface of the plastic mold element exhibits the characteristics of low water absorption rate, solvent resistance, swelling resistance, and low chemical reactivity, so as to facilitate the removal of the plastic mold from the adjacent surface of the spectacle lens.

[0029] The plastic used for the plastic mold element preferably does not have residual chemical functional groups, so as to avoid the formation of ionic or covalent bonds due to the chemical reaction between the functional groups on the surface of the plastic mold and the casting monomers of the produced spectacle lens. In one embodiment, these functional groups are selected from the group consisting of: C=C, -COOH, -OH, -CONH2, -SH, -CO-, -COH, -SO3H, and -NH2.

[0030] The plastic used as the plastic mold element preferably has a water or solvent absorption rate in the range of 0% to 0.5% by weight, more preferably in the range of 0% to 0.1% by weight, and most preferably in the range of 0% to 0.01% by weight. A water or solvent absorption rate of 0% means that the plastic does not absorb water or solvent at all. The lower the water or solvent absorption rate, the smaller the tendency of swelling will be. The term "absorption rate" refers to the maximum ability of a material to absorb water or solvent in an environment rich in water or solvent.

[0031] The glass mold element according to the present invention is a mold element made of glass. "Glass" is amorphous and is usually a transparent amorphous solid formed by cooling a melt to rigidity without crystallization.

[0032] The metal mold element according to the present invention is a mold element made of metal. For example, metals such as steel, iron-nickel alloy, and tungsten alloy can be used.

[0033] By configuring one of the mold elements to be made of plastic and the other mold element to be made of glass or metal, the present invention overcomes the problems existing in mold apparatuses using two thermoplastic mold elements and in mold apparatuses using two glass mold elements or two metal mold elements. During the molding process of the casting process of the present invention, the glass or metal mold element ensures minimal deformation of the shape of the spectacle lens on one side of the spectacle lens due to its rigidity and strong mechanical properties, while the plastic mold element tends to deform to release the curing strain, thereby allowing less deformation of the glass or metal mold element on the other side compared to conventional mold apparatuses using two glass mold elements or two metal mold elements. Therefore, a more accurate surface profile can be replicated for the glass or metal mold element side of the spectacle lens. In addition, the deformation of the plastic mold element helps to minimize the degree of strain on the spectacle lens. Since the degree of deformation is controlled by the degree of monomer shrinkage, and for a given spectacle lens material, the degree of monomer shrinkage is a fixed value, the desired lens shape on the other side of the lens can also be achieved more stably. When the two mold elements are made of thermoplastics as in the prior art, during molding, the mold elements will experience excessive shrinkage and deformation, so it will be difficult to predict or control the final spectacle lens shape. It has been proven that by combining a plastic mold element with a glass or metal mold element, significant good control of the surface profile can be achieved and the residual stress can be reduced.

[0034] On the other hand, by using one plastic mold element, the present mold apparatus can easily and precisely design the profile and surface geometry of the spectacle lens while saving the cost and time of manufacturing the mold. It is well known that glass molds are difficult to manufacture according to strict standards and with complex designs, and metal molds are not efficient in terms of cost and time for large-scale manufacturing. Nevertheless, the glass or metal mold element of the present invention can provide mechanical support during the molding process, thereby producing a spectacle lens with a precisely desired surface profile and geometry when combined with the plastic mold element. The glass or metal mold element of the present invention entrusts the complex lens surface profile and geometry to the plastic mold element. The very combination of (i) the glass or metal mold element and (ii) the plastic mold element can achieve the optimal molding of the spectacle lens, even with microstructures on the surface of the spectacle lens, overcoming the problems of glass mold apparatuses, metal mold apparatuses, and plastic mold apparatuses.

[0035] Preferably, the microstructure can be formed on the concave surface or convex surface of the plastic mold element. The microstructure is particularly used as a diffraction grating for visible light, preferably for color stripe correction in spectacle lenses.

[0036] In a preferred embodiment, the front surface of the spectacle lens is formed by a plastic mold element, and the back surface of the spectacle lens is formed by a glass mold element or a metal mold element. The term "front surface" refers to the surface of the lens that is intended to be assembled away from the eye according to Section 3.2.13 of DIN EN ISO 13666:2019(E), and the term "back surface" refers to the surface of the lens that is intended to be assembled closer to the eye according to Section 3.2.14 of DIN EN ISO 13666:2019(E).

[0037] The mold device of the present invention is particularly suitable for manufacturing spectacle lenses with microstructures. In one embodiment, the plastic mold element according to the present invention is configured to provide a microstructure on the surface of the spectacle lens to be manufactured, preferably the front surface. These microstructures on the surface of the plastic mold element correspond to the negative pattern of the microstructure to be formed on or in the spectacle lens to be manufactured. In this regard, the plastic mold element according to the present invention includes microstructures formed in relief.

[0038] For this purpose, in one embodiment, the plastic mold element can be manufactured by injection molding such that a negative pattern of the microstructure is formed on the surface, or by directly micro-machining a negative pattern of the microstructure on the plastic mold element. Injection molding will be suitable for mass-producing plastic mold elements with microstructures and is also cost-effective because injection molding facilitates microstructure replication. Injection molding is a particularly preferred method for mass-producing thermoplastic mold elements.

[0039] In another embodiment, the plastic mold element can be made by a standard spectacle lens casting process using a glass mold device or a metal mold device. Using a glass mold device will be preferred because a glass mold device is particularly suitable for mass-producing thermosetting plastic mold elements. In cases where it is necessary to form complex and delicate microstructures in relief on the plastic mold element by a casting process, it is recommended to use a metal mold device because the microstructure can be produced on the metal mold by precision machining. Therefore, in one embodiment of producing a plastic mold element with a microstructure by a casting process, a metal mold device is used for production.

[0040] In the present device, microstructures (which may also be referred to as microlenses) can be formed on a plastic mold element. Plastic mold elements are preferred for microstructures because it may be difficult to accurately and precisely fabricate fine and complex microstructures on the surface of a glass mold element. Further, although metal mold elements can produce fine and complex microstructures, they are not recommended because large-scale production of metal mold elements can be extremely time-consuming and costly. In particular, in cases where a plastic mold element with microstructures in the form of concavities and convexities on its surface needs to be produced, for the above reasons, it is preferred to produce the plastic mold element by injection molding.

[0041] To reduce the workload of mold opening, in one embodiment of the present invention, a mold release agent can be used on the plastic mold element. The mold release agent gives the plastic mold element a low surface tension by forming a non-reactive barrier (anti-sticking) to the spectacle lens material, thereby enabling the production of spectacle lenses with high quality.

[0042] In one embodiment, the plastic mold element is coated with a mold release agent that contains at least one selected from the group consisting of aliphatic hydrocarbons, fluorocarbons, silicates, silicone oils, waxes, and long-chain alkyl derivatives. The coating technique can be any conventional means, such as dip coating, spraying, wiping, or other surface treatment methods. In one embodiment, the plastic mold element can be dip-coated in the mold release agent to form a thin coating that reduces the intermolecular interaction between the two contacting surfaces or prevents such close contact between the two surfaces. The thin coating is preferably a temporary coating rather than a permanent coating, so it does not cause defects on the mold surface and does not inhibit the curing of the spectacle lens material.

[0043] Preferably, the coating of the mold release agent is configured to be thin as long as good lens separation performance can be achieved. In a preferred embodiment, the thickness of the thin coating of the mold release agent formed on the surface of the plastic mold element is less than 2 μm, more preferably less than 1 μm, and most preferably less than 0.5 μm. A thickness greater than 2 μm can still provide acceptable separation performance, but it may cause adverse surface defects such as stains, bubbles, pinholes, and other problems such as premature separation of the spectacle lens.

[0044] In this embodiment, the mold release agent is external (or non-permanent) and tends to form a thin coating on the surface. The external mold release agent is not limited to this, but can contain at least one selected from the group consisting of aliphatic hydrocarbons, fluorocarbons, waxes, and long-chain alkyl derivatives.

[0045] Aliphatic hydrocarbons are hydrocarbons based on carbon atom chains, such as alkanes, alkenes, alkynes, and cycloalkanes. Fluorocarbons are chemical compounds with carbon-fluorine bonds, such as polytetrafluoroethylene, polyvinylidene fluoride, fluorinated ethylene propylene, preferably water-based fluorocarbons. The wax contained in the mold release agent can be stearamide wax, paraffin wax, hydrocarbon wax, oxidized Fischer-Tropsch wax, and polyethylene wax, but is not limited thereto. Long-chain alkyl derivatives can be C 10 -C 50 alkyl derivatives, preferably C 15 -C 40 alkyl derivatives, such as cetyl palmitate, methyl behenate, and 9-octadecenamide.

[0046] In a preferred embodiment, the mold release agent contains fluorocarbons, more preferably water-based fluorocarbons. For example, the fluorocarbon-based mold release agent DAIKIN GW-4000 is diluted in distilled water to coat thermoplastic mold elements. It has been found that fluorocarbon-based mold release agents provide a very thin coating that does not affect the mold surface and makes the mold surface cleaner, so it is suitable for casting processes using plastic mold elements. By diluting the mold release agent with water or other suitable solvents, the following further advantages are provided: good control of the coating thickness and surface tension to make it compatible with various plastic mold elements and spectacle lens materials.

[0047] Preferably, the mold release agent has a low surface tension to achieve a sliding surface. The corresponding surface energy is preferably less than 40 mN / m (dyne), more preferably less than 30 mN / m (dyne).

[0048] In another embodiment of adding the mold release agent to the formulation for forming plastic mold elements, the mold release agent tends to reduce the bonding between the plastic mold element and the spectacle lens material. Here, the internal mold release agent can contain at least one selected from the group consisting of fatty acid esters, silicone oils, phosphate compounds, and erucamide. Fatty acid esters can be caprates, octanoates, laurates, myristates, oleates, palmitates, stearates, linoleates, and / or linolenates, but are not limited thereto. Phosphate compounds can be mono-phosphates and / or di-phosphates, which optionally contain alkyl chains, oxyethylene chains, etc., but are not limited thereto.

[0049] In this embodiment, the formulation for forming plastic mold elements can be formed by mixing plastic pellets and an internal mold release agent. The internal mold release agent (such as UN) has a similar function to the external mold release agent used to coat plastic mold elements to reduce the pulling force during mold opening.

[0050] Preferably, the ratio of the internal release agent to the plastic is less than 2% by weight, preferably less than 1%, more preferably less than 0.5%. In the case of using an excessive amount of release agent, a smooth surface of the mold element may not be achieved, which means that problems such as stains, bubbles, pinholes, etc. may appear on the surface, or other problems such as premature separation of the spectacle lens may occur.

[0051] In another embodiment, the plastic mold is made by a standard lens casting process. The mold element contains an internal release agent, and the ratio of the internal release agent to the monomer is less than 1% by weight, preferably less than 0.5%, more preferably less than 0.1%. In the case of using an excessive amount of release agent, defects such as stains, bubbles, pinholes, etc. may appear on the surface of the spectacle lens, or other problems such as premature separation of the spectacle lens may occur.

[0052] In another embodiment, the plastic mold element can be formed by mixing plastic and / or monomer with an internal release agent and further coating the produced plastic mold element with an external release agent.

[0053] Compared with the prior art references using a hard multi - coating including several material layers (the hard multi - coating is optionally capped by a topcoat film such as an anti - scratch coating, an anti - reflection coating, etc. and produced by using materials such as indium tin oxide), the plastic mold element containing a release agent of the present invention provides excellent effects in reducing the close direct contact between the mold element and the spectacle lens material, greatly reducing the mold opening difficulty of the mold equipment, and minimizing the possibility of damage when used in combination with glass or metal mold elements. The hard multi - coating is considered ineffective in reducing the adhesion force between the two surfaces of the mold element and the spectacle lens material.

[0054] Most commonly, two mold elements together with a device for connecting the two mold elements form a certain volume. The device can be implemented as a gasket or a band or a ring, but is not limited thereto. This volume defines the size and surface geometry of the spectacle lens to be molded. Through the device for connecting the two mold elements, the two mold elements are kept separated and spaced apart from each other by a predetermined axial distance. In one embodiment, the mold equipment includes a gasket or a band or a ring configured to keep the two mold elements separated. In a preferred embodiment, the mold equipment includes a band. The physical properties of the band are preferably to provide good mechanical strength so that the deformation of the plastic mold element can be slightly resisted, and moderate stress in the adjacent surfaces will not affect the surface profile of the spectacle lens, but it is easier to separate the cured spectacle lens from the mold element.

[0055] In one embodiment, the molding equipment of the present invention further includes a mold element for supporting the plastic mold element.

[0056] During the thermal curing process where the curing temperature is equal to or higher than the glass transition temperature (Tg) of the thermoplastic material of the mold element, defects more severe than deformation have been observed. The term "glass transition temperature" refers to a temperature below which a completely or partially amorphous polymer is in a glassy or hard elastic, brittle state, and above which they are in a highly viscous or rubber elastic state. The glass transition temperature can be determined by differential scanning calorimetry (ISO 11357-2:2020(E)) or dynamic mechanical analysis. In this case, a molding device composed of two thermoplastic mold elements will fall apart, resulting in monomer leakage, making it impossible for the process to produce a complete lens. Therefore, for a molding device for the curing process where the curing temperature is equal to or higher than that of the plastic mold element for spectacle lenses, a mold element for supporting the plastic mold element is further added to the mold device to resist the deformation of the plastic mold element and ensure the integrity of the mold device. The mold element for supporting the plastic mold element is added to the rear side of the plastic mold element (the surface that does not form the spectacle lens). Preferably, the shape and curvature of one side of the mold element for supporting the plastic mold element should match the rear surface of the plastic mold element to seamlessly bond with the plastic mold element.

[0057] The support mold element according to the present invention is a mold element made of glass or metal, which can resist deformation at high curing temperatures.

[0058] A second aspect of the present invention relates to a method, which includes producing a mold device configured to manufacture spectacle lenses and including two mold elements. Among them, the method includes providing two mold elements, characterized in that one of the two mold elements is a plastic mold element, and the other mold element is a glass mold element or a metal mold element.

[0059] In one embodiment, the method of the present invention further includes manufacturing the plastic mold element by molding, where a microstructure is formed on the surface of the plastic mold element in the form of concavities and convexities. In a preferred embodiment, the plastic mold element is formed by injection molding or casting molding. By using the two molding processes for producing the plastic mold element, cost-effective and efficient mass production of the mold element is achieved. As explained regarding the mold device according to the first aspect of the present invention, the microstructure formed on the surface of the plastic mold element corresponds to the negative pattern of the microstructure to be formed on or in the spectacle lens to be manufactured. In the case where the plastic mold element is formed with a microstructure in the form of concavities and convexities, it is preferred to use a metal mold device for casting molding or adopt injection molding to produce the plastic mold element.

[0060] The method further comprises the following steps: applying an external mold release agent on the surface of a plastic mold element and / or manufacturing a plastic mold element containing an internal mold release agent by injection molding or casting. The plastic mold element is made of a plastic material, preferably made of a thermoplastic material and / or a thermosetting plastic. The plastic material is made of at least one selected from the group consisting of, but not limited to: polycarbonate, polyamide, polysulfone, polyester, polyetheretherketone (PEEK), polyolefin, cycloolefin copolymer (COC), cycloolefin polymer (COP), cyclic block copolymer (CBC), polythiourethane, polyurethane, methacrylate, polythiirane, and allyl diglycol carbonate. Preferably, the plastic material is at least one selected from the group consisting of: polycarbonate, polyamide, polysulfone, polyester, polyetheretherketone (PEEK), polythiourethane, polyurethane, methacrylate, polythiirane, and allyl diglycol carbonate.

[0061] In this regard, the external mold release agent contains at least one selected from the group consisting of: aliphatic hydrocarbons, fluorocarbons, waxes, and long-chain alkyl derivatives; the internal mold release agent contains at least one selected from the group consisting of: fatty acid esters, silicone oils, phosphate compounds, and erucamide. The method according to the present invention may include the step of manufacturing spectacle lenses by molding using the mold device thus produced.

[0062] The method further includes providing means for connecting two mold elements, which may be, but not limited to, a gasket or a band or a ring.

[0063] In one embodiment, the mold device according to the method may further include an additional mold element for supporting the plastic mold element. In this case, the method further includes providing to the mold device a mold element for supporting the plastic mold element. The mold element for supporting the plastic mold element is provided on the rear surface of the plastic mold element and / or may be configured to match the shape and contour of the rear surface of the plastic mold element. The method may further include providing means for connecting the plastic mold element and the mold element for supporting the plastic mold element.

[0064] A third aspect of the present invention provides a method for manufacturing spectacle lenses configured to use a mold device including two mold elements, characterized in that one of the two mold elements is a plastic mold element and the other mold element is a glass mold element or a metal mold element.

[0065] The method according to the third aspect may further include providing ophthalmic lens material to a mold apparatus and / or curing the ophthalmic lens material. If the ophthalmic lens material is a thermoplastic ophthalmic lens material and the curing temperature is equal to or higher than the glass transition temperature of the thermoplastic ophthalmic lens material, the method further includes providing to the mold apparatus an additional mold element that supports the plastic mold element.

[0066] The method may further include providing to the mold apparatus means for connecting the plastic mold element and the mold element that supports the plastic mold element. The means for connecting the mold elements may be, but is not limited to, a gasket or a band or a ring.

[0067] All relevant features and descriptions mentioned with respect to the mold apparatus according to the first and second aspects of the present invention may equally apply to the method of the present invention according to the second and third aspects.

[0068] These and other embodiments are discussed below with reference to the accompanying drawings. However, those skilled in the art will readily understand that the detailed description given herein with respect to these drawings is for explanatory purposes only and should not be construed as limiting.

[0069] Figure 1 A molding apparatus 1 according to the present invention and an ophthalmic lens 5 produced by the molding apparatus are shown. The mold apparatus includes two mold elements, one of which is a plastic mold element 2 and the other of which is a glass mold element 3. Further, the mold elements include means 4a, 4b for connecting the two mold elements, such as a gasket or a ring or a band, preferably a band. The two mold elements 2, 3 together with the means 4a, 4b for connecting the two mold elements form a cavity 5 that defines the shape and surface profile of the ophthalmic lens to be produced. Ophthalmic lens material 6 is injected into the cavity 5 of the mold apparatus 1, and thus an ophthalmic lens 7 is produced by casting.

[0070] Figure 2An exemplary example of the method according to the present invention is shown. First, here, a plastic mold element 2 having a microstructure 8 on its concave surface is manufactured by injection molding. The microstructure 8 is configured to provide a negative pattern of the microstructure to be formed on or in the spectacle lens 7 to be manufactured. Here, the plastic mold element 2 has a microstructure 8 formed in a concavo-convex form. The surface of the plastic mold element 2 having the microstructure 8 is treated by dip coating in a release agent 9, which is an external release agent. The coated plastic mold element 2a exhibits a low surface tension, enabling the spectacle lens material 6 to be more easily demolded in a subsequent stage. The coated plastic mold element 2a and the glass mold element 3 together with the devices 4a, 4b for connecting the two mold elements form a mold device 1, which has a defined space, i.e., a cavity 5, corresponding to the shape and contour of the spectacle lens 7 to be formed. The spectacle lens material 6 is injected into the cavity 5 and thermally cured to produce a spectacle lens 7 having a microstructure 10 on its surface. Due to the surface treatment of the plastic mold element 2a with the release agent 5, the produced spectacle lens 7 can be well separated from the mold device without causing any damage to the spectacle lens 7. Since the plastic mold element is manufactured by injection molding, it is preferred that the plastic mold element is a thermoplastic mold element, and correspondingly, the spectacle lens can use a thermosetting plastic spectacle lens material.

[0071] Figure 3 Another exemplary example of the method according to the present invention is illustrated. Here, in contrast to Figure 2Unlike the exemplary example depicted in [reference], the plastic mold element 2b is formed by injection molding a mixture of plastic pellets and a demolding material (not shown), which is an internal demolding material. After injecting the plastic material for the plastic mold element 2b into the cavity of the mold device for manufacturing the plastic mold element 2b, the plastic material is cooled and ejected from the mold device. By injection molding, the plastic mold element 2b is configured to have the desired microstructures 8, which have a negative pattern of the microstructures 10 to be formed on or in the spectacle lens 7. That is, the plastic mold element 2b has microstructures in the form of protrusions and depressions on its surface. The plastic mold element 2b, the glass mold element 3, and the devices 4a, 4b for connecting the two mold elements form a cavity 5 corresponding to the shape and contour of the spectacle lens 7 to be produced. The spectacle lens material 6 is inserted into the cavity 5, thermally cured, and ejected from the mold device 1, and the spectacle lens 7 having the microstructures 10 on its surface is formed by casting. Due to the improved properties exhibited by the demolding agent mixed into the plastic mold element 2b, the spectacle lens 7 can be easily and smoothly demolded without being significantly restricted or damaging the contour or geometry of the spectacle lens. Since the plastic mold element is manufactured by injection molding, preferably, the plastic mold element is a thermoplastic mold element, and correspondingly, the spectacle lens can use a thermosetting plastic spectacle lens material.

[0072] Figure 4 FIG. illustrates a third exemplary example of the method according to the present invention. Here, unlike Figure 3 the exemplary example depicted in [reference], the plastic mold element 2c is formed by casting a mixture 11 of a plastic monomer formulation and a demolding agent (internal demolding agent). After filling the mixture 11 for the plastic mold element 11 into the cavity of the metal mold device 12 for manufacturing the plastic mold element 2c, the mixture is cooled and demolded from the metal mold device 12. The metal mold device 12 is preferably used for casting the plastic mold element 2c having the microstructures 8. By casting, the plastic mold element 2c is configured to have the desired microstructures 8, which have a negative pattern of the microstructures 10 to be formed on or in the spectacle lens 7. That is, the plastic mold element 2c has microstructures in the form of protrusions and depressions on its surface. When the plastic mold element 2c is manufactured by casting, preferably, the plastic mold element 2c is a thermosetting plastic mold element. After producing the plastic mold element 2c, the plastic mold element 2c and the glass mold element 3 together form the mold device 1 according to the present invention, and the spectacle lens 7 having the microstructures 10 is produced.

[0073] Other variants not shown in the drawings can also be implemented. For example, although the above Figures 1 to 4The embodiments involved are such that microstructures can be provided on the concave surface of a plastic mold element to produce spectacle lenses having microstructures on the convex surface, but microstructures can also be provided on the convex surface of a plastic mold element to produce spectacle lenses having microstructures on the concave surface. Another example would be that, although Figure 2 and Figure 3 two embodiments are described as using plastic mold elements made by injection molding, plastic mold elements can also be prepared by direct micro-machining. Additionally, in Figures 1 to 4 , the glass mold element 3 can be replaced by a metal mold element.

[0074] Figure 5 Figure 4 illustrates a fourth exemplary example of the present invention. Here, different from the exemplary example depicted in Figures 1 to 4 , the mold element 13 that supports the plastic mold element is included as part of a mold device assembled from washers or bands or rings. The mold element 13 that supports the plastic mold element is made of glass and has a surface and profile that match the rear surface of the plastic mold element 2. The mold element 13 is added to the rear side of the plastic mold element 2. During the spectacle lens curing step, the mold element 13 resists the tendency of the plastic mold element 2 to deform and ensures the integrity of the mold device 1 and the desired shape of the spectacle lens 7.

Claims

1. A mould device (1) configured to manufacture spectacle lenses (7) and comprising two mould elements (2, 3), characterized in that, One of the two mold elements is a plastic mold element (2), and the other mold element is a glass mold element or a metal mold element (3).

2. The mould device (1) according to claim 1, characterized in that, The plastic mold element (2) contains a release agent (9).

3. The mould device (1) according to claim 1 or 2, characterized in that, The plastic mold element (2) is coated with a release agent (9).

4. The mould device (1) according to claim 3, characterized in that, The release agent (9) is formed as a coating on the plastic mold element (2a), and the thickness of the coating is selected from the range group consisting of less than 2 μm, less than 1 μm, or less than 0.5 μm.

5. The mould device (1) according to claim 1 or 2, characterized in that, The plastic mold element (2b) is formed by mixing a plastic material and a release agent by injection molding or casting.

6. The mould device (1) according to claim 3 or 4, characterized in that, The release agent (9) contains at least one selected from the group consisting of aliphatic hydrocarbons, fluorocarbons, waxes, and long-chain alkyl derivatives.

7. The mould device (1) according to claim 5, characterized in that, The release agent contains at least one selected from the group consisting of fatty acid esters, silicone oils, phosphate compounds, and erucamide.

8. The mould device (1) according to claim 6, characterized in that, The release agent (9) contains a water-based fluorocarbon.

9. The mould device (1) according to any one of the preceding claims, characterized in that, The plastic mold element (2) is made of a thermoplastic and / or a thermosetting plastic.

10. The mould device (1) according to any one of the preceding claims, characterized in that, The spectacle lens (7) is a thermosetting plastic spectacle lens, and the plastic mold element (2) is a thermoplastic mold element.

11. The mould device (1) according to any one of the preceding claims, characterized in that, The plastic mold element (2) is configured to define the front surface of the spectacle lens, and the glass mold element or the metal mold element (3) is configured to define the back surface of the spectacle lens.

12. The mould device (1) according to claim 11, characterized in that, The plastic mold element (2) is configured to define the front surface of the spectacle lens, and the glass mold element is configured to define the back surface of the spectacle lens.

13. The mould device (1) according to any one of the preceding claims, characterized in that, The plastic mold element (2) includes a microstructure (8) in the form of unevenness on the surface of the plastic mold element (2).

14. The mould device (1) according to any one of the preceding claims, characterized in that, Further included is a mold element (13) for supporting the plastic mold element.

15. A method of manufacturing spectacle lenses (7) using a mould device (1) comprising two mould elements (2, 3), characterized in that, One of the two mold elements is a plastic mold element (2), and the other mold element is a glass mold element or a metal mold element (3).

16. A method of manufacturing a mould device (1) configured to manufacture spectacle lenses and comprising two mould elements (2, 3), wherein, The method includes providing two mold elements, characterized in that one of the two mold elements is a plastic mold element (2), and the other mold element is a glass mold element or a metal mold element (3).

17. The method according to claim 15 or 16, wherein, Further included is a step of injection molding or casting the plastic mold element (2).

18. The method according to claim 17, wherein, In the injection molding step, the plastic mold element (2) is a thermoplastic mold element including a microstructure (8) formed in the form of unevenness on the surface of the plastic mold element (2).

19. The method according to claim 17, wherein, In the casting step, the plastic mold element (2) is a thermosetting plastic mold element, and a metal mold device (12) is used for casting.

20. The method according to any one of claims 15 to 19, wherein, Further included is a step of coating the surface of the plastic mold element (2) with a release agent (9) and / or a step of manufacturing the plastic mold element (2) by injection molding or casting a mixture of a plastic and a release agent.

21. The method according to claim 20, wherein, The release agent (9) for the coating step contains at least one selected from the group consisting of aliphatic hydrocarbons, fluorocarbons, waxes, and long-chain alkyl derivatives.

22. The method according to claim 20, wherein, The release agent for the injection molding or casting step contains at least one selected from the group consisting of fatty acid esters, silicone oils, phosphate compounds, and erucamide.

23. The method according to any one of claims 15 to 22, wherein, Further provided is a mold element (13) that supports the plastic mold element.

24. The method according to claim 23, wherein, The mold element (13) that supports the plastic mold element is provided when the curing temperature of the spectacle lens is equal to or higher than the glass transition temperature (Tg) of the thermoplastic material of the plastic mold element.

25. The method according to claim 15, wherein, The front surface of the spectacle lens is determined by the plastic mold element (2), and the back surface of the spectacle lens is determined by the glass mold element or the metal mold element (3).

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