Optical lens material, method for manufacturing optical lens, and glass lens

Abstract

A method for manufacturing an optical lens according to an embodiment of the present disclosure may include: providing a mixture by mixing glass particles, a polymer filled between the glass particles, and an additive; injection molding the mixture by using a mold assembly having a lens shape; debonding the polymer from the lens molding injection-molded into the lens shape; sintering the glass particles in the molded part from which the polymer has been removed by debonding; and processing the sintered molded part to provide the glass lens.

Description

Technical Field

[0001] Embodiments of this disclosure relate to a material for optical lenses. Embodiments of this disclosure relate to a method for manufacturing optical lenses using hybrid materials. Embodiments of this disclosure relate to a glass lens manufactured using a method for manufacturing optical lenses. Background Technology

[0002] Glass is transparent, strong, and possesses excellent thermal and chemical stability, making it a versatile material used in a wide range of industries, including windows, solar panels, optical lenses, medical devices, and chemical and life science applications. In the field of optical lenses, glass offers significant advantages, including a wide refractive index range, low thermal expansion, and excellent durability. When processing glass optical lenses, pressure is applied to the glass at high temperatures to shape it into the desired form, or it is processed using a grinding machine. However, glass has a melting point of approximately 1700 degrees Celsius, which affects the lifespan of molds during melting and processing. Furthermore, its high durability makes physical forming difficult. These conventional techniques are not suitable for mass production and present problems due to high processing costs. Summary of the Invention

[0003] Technical issues

[0004] Embodiments of this disclosure provide a material for an optical lens comprising a glass material, a polymer, and additives. Embodiments of this disclosure also provide a method for manufacturing an optical lens, comprising: injection molding a material for an optical lens comprising a glass material, a polymer, and additives using a heat treatment process; debonding the polymer within the molding material; and then manufacturing the molding material or the glass lens for the glass lens. Embodiments of this disclosure may provide a glass lens from which the polymer is removed by injection molding a material for an optical lens comprising a glass material, a polymer, and additives, and a process of debonding the polymer.

[0005] Technical solution

[0006] According to embodiments of this disclosure, a method for manufacturing an optical lens includes: providing a mixture by mixing glass particles, a polymer filling between the glass particles, and additives; injection molding the mixture using a mold assembly having a lens shape; debonding the polymer from a lens molded part that has been injection molded into a lens shape; sintering the glass particles in the molded part from which the polymer has been removed by debonding; and processing the sintered molded part to provide a glass lens.

[0007] According to an embodiment, the temperature for injection molding the product can be lower than the temperature for debinding the polymer. The sintering temperature of the glass particles can be higher than both the temperature for debinding the polymer and the temperature for injection molding the product. The glass particles may include silica particles, and the polymer may include a thermoplastic resin material. Each glass particle may have a size of 800 nm or smaller, and the glass particles may be mixed in an amount of 70% by weight or volume or less relative to the total mixture.

[0008] According to embodiments of this disclosure, the solvent used for debinding may include at least one of distilled water, ethanol, and isopropanol. The sintering process may utilize pressurless discharge plasma sintering (SPS). The mold assembly for injection molding may include a shape-retaining mold material.

[0009] The optical lens material according to embodiments of the present disclosure includes glass particles; and a mixed material filled between the glass particles and having a refractive index different from that of the glass particles. Each glass particle has a size of 800 nm or smaller, and the glass particles may be mixed in an amount of 70% or less of the mixed material.

[0010] According to embodiments of this disclosure, the blending material may be a polymer or monomer filling the spaces between the glass particles. The blending material may also fill the empty spaces between the glass particles. The optical lens material may further include additives connecting the glass particles and the blending material. The glass particles each have a size of 50 nm to below 800 nm, and the glass particles may be blended in an amount of 20% to 70% relative to the blending material.

[0011] Beneficial effects

[0012] According to embodiments of this disclosure, since glass lenses are manufactured using injection molding processes typically used for manufacturing plastic lenses, limitations on processable shapes can be reduced. Specifically, injection molding of glass lenses can be performed at relatively low temperatures, thereby reducing manufacturing time, facilitating mass production, and lowering production and processing costs.

[0013] Furthermore, since glass lenses are manufactured using a plastic injection molding process, spherical, aspherical, and freeform shapes can be easily processed according to the shape of the injection mold. Additionally, the sintering time of the lens can be reduced. Specifically, due to the use of a low-voltage discharge plasma sintering process, the sintering time can be reduced to approximately 30 minutes. Therefore, the manufacturing cost of glass lenses can be reduced, and productivity can be increased.

[0014] The embodiments disclosed herein can improve the price competitiveness of materials used for optical lenses or glass lenses made therefrom, and can improve the reliability of glass lenses. Attached Figure Description

[0015] Figure 1 This is a schematic diagram illustrating a lens manufacturing process using optical lens materials according to an embodiment of the present disclosure.

[0016] Figure 2 This is a diagram illustrating a lens manufacturing process using optical lens materials according to an embodiment of the present disclosure.

[0017] Figure 3 It is shown Figure 2 A flowchart of the lens manufacturing process.

[0018] Figure 4 This is a diagram illustrating the process of manufacturing a lens from an optical lens material using a mold assembly according to an embodiment of the present disclosure.

[0019] Figure 5 It is shown from the basis Figure 4 An example diagram of a manufactured lens shape.

[0020] Figure 6 This is a diagram illustrating the process of manufacturing a lens using an optical lens material and an aspherical mold assembly according to an embodiment of the present disclosure.

[0021] Figure 7 This is a graph comparing the sintering times of the lens of the present invention and a comparative example. Detailed Implementation

[0022] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0023] The technical spirit of this disclosure is not limited to the embodiments described, and can be implemented in various other forms. One or more components may be selectively combined and substituted for use within the scope of the technical spirit of this disclosure. Furthermore, the terminology used in the embodiments of this disclosure (including technical and scientific terms) is to be interpreted as having a meaning commonly understood by one of ordinary skill in the art to which this disclosure pertains, unless explicitly defined and described. Commonly used terms, such as those defined in dictionaries, should be interpretable in light of the contextual meaning of the relevant art.

[0024] Furthermore, the terminology used in the embodiments of this disclosure is for the purpose of explaining the embodiments and is not intended to limit the disclosure. In this specification, unless specifically stated otherwise in the phrase, the singular form may also include the plural form, and in the case of statements of A and / or at least one (or more) of B, C, it may include one or more of all combinations that can be combined with A, B, and C. In describing embodiments of this disclosure, terms such as first, second, A, B, (a), and (b) may be used. Such terms are used only to distinguish the component from other components and may not determine the nature, order, or process of the corresponding constituent elements, etc. And when describing a component as “connected,” “joined,” or “engaged” to another component, the description may include not only direct connection, joining, or engagement to the other component, but also "connected,” “joined,” or “engaged” through other components between the component and the other component. Furthermore, when described as being formed or disposed “above” or “below” each component, the description may include not only the case where the two components are in direct contact with each other, but also the case where one or more other components are formed or disposed between the two components. In addition, when expressed as "above" or "below", it can refer to the downward direction and the upward direction relative to a component.

[0025] Figure 1 This is a schematic diagram illustrating a lens manufacturing process using optical lens materials according to an embodiment of the present disclosure. Figure 2 This is a diagram illustrating a lens manufacturing process using optical lens materials according to an embodiment of the present disclosure. Figure 3 It is shown Figure 2 A flowchart of the lens manufacturing process. Figure 4 This is a diagram illustrating the process of manufacturing a lens using an optical lens material using a mold assembly according to an embodiment of the present disclosure, and Figure 5 It shows from through Figure 4 An example diagram of a manufactured lens shape.

[0026] Reference Figures 1 to 3The material of the optical lens can be a mixture obtained by mixing glass particles 110 and at least one other material. For example, the material of the optical lens may include glass particles 110 and at least one polymer 120 or spaces from which polymer 120 has been removed. The mixed material may be a space or plastic material having a refractive index different from that of the glass particles 110 and in contact with the glass particles 110. The material of the optical lens may also include additives 105 for mixing and stabilizing the mixture of glass particles 110 and polymer 120. The material of the optical lens may include a material obtained by injection molding the mixture. The material for the optical lens may include a material obtained by debinding or sintering after the mixture has been injection molded. Here, the material of the optical lens may include glass particles 110 and a material having empty spaces from which polymer 120 has been removed between the glass particles.

[0027] The material for the optical lens can be manufactured through a material mixing step S1, which involves mixing glass particles 110, polymer 120, and additive 105; an injection molding step S3, which involves injection molding the material mixed in the material mixing step S1 into a lens shape; and a step S6, which involves providing the glass lens after the injection molding step S3. After the injection molding step S3 and before providing the glass lens, a debinding step S4, which removes at least one of polymer 120 and additive 105, and a sintering step S5, which involves sintering the molded part made of the glass material, may also be included. Here, the temperature during the injection molding step can be a first temperature, the temperature during the debinding step can be a second temperature, and the temperature during the sintering step can be a third temperature. The first temperature can be lower or higher than the second temperature; for example, it can be lower than the second temperature. The third temperature can be higher than both the first and second temperatures. The first temperature can be within the temperature range used for plastic molding, and the third temperature can be within the temperature range used for glass transition.

[0028] In the material mixing step S1, glass particles 110 and polymer 120 are mixed, and additive 105 is added to the mixture. Additive 105 can connect polymer 120 and glass particles 110, between polymers 120, and between glass particles 110. Glass particles 110 can be made of a transparent glass material, and each particle can have a width or diameter of 800 nm or less, for example, in the range of 50 nm to 800 nm. Glass particles 110 can include spherical particles. Glass particles 110 can include at least one or all of spherical particles and irregular particles. Depending on the size and shape of the glass particles 110, variations in the shrinkage rate of the glass lens can be adjusted or selected. The glass material can be based on silica particles (SiO2) to manufacture quartz-based lenses. As another example, the particles can be made of another transparent material capable of determining the refractive index and Abbe number of the glass material. For example, when using borosilicate glass lenses, the glass particles may include a composition of 80.6 wt% silicon dioxide (SiO2), 13 wt% boron oxide (B2O3), 4 wt% sodium oxide (Na2O), and 2.3 wt% aluminum oxide (Al2O3). To manufacture glass lenses made from high-refractive-index materials, the glass particles may include materials with added heavy metal oxides such as lanthanum oxide (La2O3) or titanium oxide (TiO2).

[0029] Polymer 120 may comprise a plastic material or a thermoplastic resin. Polymer 120 may be nanoparticles smaller than the size of glass particles 110. As another example, polymer 120 may be provided in solution form. As another example, monomer particles may be included instead of polymer. Polymer 120 may be particles or a solution smaller than the size of glass particles 110 to fill the spaces between glass particles 110. One or more types of polymers or monomers may be used to fill and connect the spaces between glass particles 110; for example, multiple types of resins may be mixed. After such polymers or monomers are filled into the empty spaces between glass particles, the glass particles can be more firmly fixed by performing a heat treatment process, a UV treatment process, or an extrusion process S2. Because the polymer or monomer is present between the glass particles, the blended material can be provided as a polymeric material (i.e., a plastic material) even if the blended material includes glass particles. Polymer 120 or monomers may comprise at least one of polyvinyl butyral, polyethylene glycol, 2-hydroxyethyl methacrylate, and 2-phenoxyethanol to fill the spaces between glass particles 110.

[0030] The additive 105 of the lens material may include various materials such as curing agents for polymerization and coupling agents for forming strong bonds between particles. Additive 105 may include at least one of 2,2'-azobis(2-methylpropionitrile) and tetraethylene glycol diacrylate. Glass particles 110 may be mixed in an amount of 70% or less relative to polymer 120 or the mixture, for example, in an amount or mass ratio of 20% to 70%. That is, in the mixture, the mass ratio of glass particles 110 may be equal to or less than the mass of polymer 120. Conversely, in the mixture, the mass ratio of glass particles 110 may be equal to or greater than the amount of polymer 120. The content of glass particles 110 may be determined based on the control of the shrinkage rate of the final product, the isotropic nature of the shrinkage, and the control of defects during the debinding and sintering processes. After mixing, the material may further contain a liquid solvent, which may be removed during the oven process or at room temperature, and if the solvent is not dried or removed, materials other than the glass material may cause defects during the debinding and sintering processes.

[0031] After extruding the mixture in step S2, Figure 1 The extruded mixture 112 shown is molded into injection molded bodies with lens shapes 113A and 113B at a temperature similar to the injection molding temperature of the plastic material. Then, through a debinding process and a sintering process, the debinding step S4 removes… Figure 2 The polymer 120 present in the injection molded body 113 shown, and Figure 2 The molded part 114 shown, with empty spaces 120A from which the polymer has been removed, is provided by a sintering process as a glass lens molded part 115 without internal empty spaces. The sintered material from which the polymer 120 has been removed can be provided as individual glass lenses by cutting and processing. Additives can also be removed during the above-described process. That is, when synthesizing lens material, since the polymer 120 exists in the spaces between the glass particles 110 in the material, the injection molding process into the lens shape can be performed at a temperature below the glass melting point of 1700 degrees. Furthermore, the injection-molded material undergoes a debinding process at a temperature of 250 degrees or higher, for example, in the range of 250 to 700 degrees or in the range of 400 to 600 degrees. The debinding process is a process of removing the polymer from between the molded glass particles. That is, the polymer 120 can be removed by reacting with oxygen in the air at a temperature of approximately 300 degrees to convert it into a gas containing carbon dioxide.

[0032] The material from which polymer 120 has been removed has a lens shape formed by glass particles, and empty spaces remain in the area where polymer 120 has been removed. To remove these empty spaces, the part is sintered near the glass transition temperature of the glass material. At this time, the glass particles are melted by high-temperature energy and transform into a slightly viscous state, and combine with surrounding particles to fill the empty spaces. Through this sintering process, the empty spaces between the glass particles are removed and the density of the glass material increases, thereby turning the material into glass and allowing it to be manufactured into a glass body with a lens shape.

[0033] The following sections will describe specific injection molding, polymer debinding, and sintering processes.

[0034] <Injection molding process S2 of the mixture>

[0035] Curing Figure 1 The monomers or polymers in the mixture 111 shown. At this time, according to additive 105, the mixture can be cured by various methods such as light or heat. Furthermore, since the material undergoes significant shrinkage after the debinding and sintering processes, the size of the injection-molded mixture can be mixed and extruded to a larger size, taking shrinkage into account. Depending on the shape, diameter, and thickness of the lens, the shrinkage of the mixture can occur isotropically or anisotropically. To compensate for this shrinkage, the shape of the injection mold can be corrected. The injection molding conditions for the mixture, such as injection pressure, time, and temperature, can be adjusted according to the polymer material added during the synthesis of the mixture. For example, the injection pressure for molding the injection product can be in the range of 5 bar to 20 bar. The injection temperature can be in the range of 100 degrees to 170 degrees. The injection time can be in the range of 4 seconds to 15 seconds. Here, since the concentration of glass particles 110 (i.e., silica particles) in the mixture changes the viscosity and elasticity of polymer 120, the injection conditions can be adjusted within a reasonable range taking this into account.

[0036] like Figure 4As shown, a mold assembly for injection molding may include a first core 101 and a second core 102. The first core 101 and the second core 102 may be made of a metallic material capable of injection molding glass materials. The second core 102 may include a mold 103 having a second cavity R2 formed therein. The mold 103 may be made of a metallic material and may face the first core 101. The first core 101 may include a plurality of first cavities R1 spaced apart from each other in a region facing the mold 103, and the mold 103 may include second cavities R2 disposed in regions respectively facing the first cavities R1. The shape formed by the combination of the first cavities R1 and the second cavities R2 can form a cavity having a lens shape to be manufactured. The lens shape may include at least one of the following: a shape with two concave surfaces, a shape with one concave surface and the other convex surface, a shape with two convex surfaces, or a shape with one convex surface and the other concave surface. One surface of the lens may be a light-incident surface, and the other surface may be a light-excising surface. At least one of the surfaces may be spherical. As another example, at least one of the surfaces may be aspherical.

[0037] The number of lens cavities formed within the first core 101 and the second core 102 can be one or more, but may include eight or twelve cavities to improve productivity. The first cavity R1 and the second cavity R2 may be provided in a symmetrical configuration, taking into account the injection rate and pressure of the mixture filling each cavity. The second core 102 may include a through-hole 105 formed therein, and the through-hole 105 may have a size that allows the introduction of nanoscale glass particles or mixtures, and the mixture can be injected through the through-hole 105. To allow the mixture to flow in, the flow channel 104, which serves as a flow path between the first core 101 and the second core 102, may have a size or diameter that does not affect the flowability of the nanoscale glass particles. When the mixture is filled into the cavities R1 and R2, an injection molded body 153 having lens shapes 151 and 152 can be provided. The injected mixture is shaped into a lens shape and has a structure in which polymer is filled between the glass particles. At this time, the lens shapes 151 and 152 can be connected to each other via a connecting portion 154. Here, the first core 101 can be a fixed part, and the second core 102 can be a movable part attached to or separate from the first core 101. An extrusion process prior to injection molding can be performed by injecting a mixture and then applying pressure through the through-hole 105 to extrude the mixture. As another example, such as Figure 6 As shown, the mixture can be placed in the lower cavity, and then injection molding can be performed by pressing the upper core.

[0038] <Polymer Debinding Process S4>

[0039] The injected mixture is molded into a lens shape and has a structure in which polymer is filled between glass particles. To extract pure glass material, a polymer debinding step S4 is performed to remove polymer 120 present between the glass particles. The polymer debinding step S4 may include a solvent debinding process followed by a high-temperature debinding process, depending on the type, particle size, and chemical properties of the polymer present between the glass particles. The solvent debinding process is a method of debinding by gradually dissolving polymer 120 in a solvent. The solvent used for debinding may include at least one of distilled water (H₂O), ethanol (EtOH), and isopropanol (IPA), and may include any solvent that slowly dissolves polymer 120 without rapid dissolution. For effective debinding, the solvent debinding temperature may be 50 degrees Celsius or lower, for example, in the range of 30 to 50 degrees Celsius, and the debinding time may be less than 10 hours, for example, in the range of 1 to 10 hours, depending on the type of polymer. The solvent debinding process may be omitted depending on the type of polymer to improve productivity. After the solvent debinding process, the injection molded body is completely dried to remove residual solvent and then undergoes a high-temperature debinding process. If the solvent remains, defects may occur in the injection molded body during the high-temperature debinding process, and the injection molded body may crack due to the sudden evaporation of the solvent. The high-temperature debinding process is the process of removing the polymer present between glass particles at high temperatures. Most polymers can react with oxygen in the air at temperatures of approximately 300 degrees Celsius to be removed as a gas containing carbon dioxide. Furthermore, to completely remove organic materials from the injection molded body, the high-temperature debinding process can be performed at temperatures of 500 degrees Celsius or higher, for example, in the range of 500 to 700 degrees Celsius, and preferably in the range of 550 to 650 degrees Celsius. During the heating used for debinding, rapid temperature changes can cause defects in the injection molded body. For example, a rapid temperature rise to the debinding temperature can cause strong flow of polymer between glass particles or generate a large amount of gas, resulting in cracks. Therefore, the heating and cooling rate from room temperature to the debinding temperature can be 20 degrees Celsius / minute or less, for example, in the range of 0.5 degrees Celsius / minute to 20 degrees Celsius / minute. The holding time at the debonding temperature can be 5 hours or less, for example, in the range of 1 to 5 hours.

[0040] <Sintering process S5 of the mixture>

[0041] The injection molded body from which the polymer has been removed has a structure in which the polymer between the glass particles is removed, leaving only the glass particles. The empty spaces between the glass particles cause defects such as light scattering; therefore, even though only the glass particles remain after debonding, the molded part may be opaque. Therefore, a high-temperature sintering step S5 is performed to remove the empty spaces in the injection molded body and increase the density of the molded part. In the sintering step S5, the glass particles transform into a glassy state and bond together. Through this process, the empty spaces between the glass particles are filled, thereby forming a complete glass. The sintering temperature can be below 1500 degrees Celsius, for example, in the range of 1000 to 1500 degrees Celsius, depending on the material of the glass particles. The sintering temperature can be determined near the glass transition temperature of the material. For example, the sintering temperature for manufacturing quartz SiO2 lenses can be approximately 1300 degrees Celsius or in the range of 1250 to 1350 degrees Celsius. The rate of temperature increase and decrease from room temperature to the sintering temperature can be 500 degrees Celsius per minute or less, for example, in the range of 5 to 500 degrees Celsius per minute. The holding time at the sintering temperature can be less than 3 hours, for example, in the range of 5 minutes to 3 hours. When low-pressure discharge plasma sintering technology is applied, the sintering time can be reduced to within 1 hour, and as... Figure 7 As shown in (a), the time can be reduced to below 30 minutes. Although this can vary depending on the material, performing the sintering process within one hour can reduce manufacturing costs and increase productivity. Conversely, Figure 7 The comparative example shown in (b) uses an oven sintering process that requires approximately 10 hours, which may reduce productivity and increase manufacturing costs.

[0042] During the sintering process, the crystallinity of the glass can vary depending on the sintering temperature, holding time, and heating and cooling rates. To produce transparent glass lenses, sintering conditions that inhibit glass crystallization must be utilized. For example, low-voltage discharge plasma sintering conditions for manufacturing lenses made of quartz (SiO2) material can be a heating rate of 225 degrees Celsius / minute, a holding time of 1300 degrees Celsius for 5 minutes, and a cooling rate of 60 degrees Celsius / minute, and these conditions can vary depending on the material of the glass particles. Shrinkage of the injection-molded lens occurs because empty spaces are removed from the lens molding during sintering step S5. Although shrinkage compensation is performed in the injection mold, for isotropic shrinkage, correction can be performed using a first core 101 and a second core 102, each having a shape-retaining metal, or a first core 101 and a mold 103. The shape-retaining metal maintains the shape of the injection molded body during sintering and can induce isotropic shrinkage by providing uniform heat transfer to the injection molded body. One surface of the sintered lens can be a light-incident surface, and the other surface can be a light-exiting surface. At least one of the surfaces can be spherical. As another example, at least one of the surfaces can be aspherical.

[0043] like Figure 5 As shown, the gate portion 153A retained on the molded part 153 having lens shapes 151 and 152 is cut off, and the individual glass lens 150 can be manufactured by injection molding. Cutting the gate portion 153A can include various methods such as using a high-temperature blade, laser cutting, or ultrasonic cutting to minimize deformation of the lens shape. The retained connecting portion 154 after injection molding can be treated with a specific solvent to remove the polymer and extract the glass material. Therefore, recycling of the glass particles is possible.

[0044] Figure 7 An example of a molding die for forming an aspherical lens is shown. Examples of forming the aforementioned aspherical surface may include a polymer debonding process and a sintering process of the debonded molded product. Figure 7As shown, the molding die for an aspherical lens includes an upper die 30 and a lower die configured to be joined and separated from each other, an upper core 31 and a lower core 41 formed on the upper die and the lower die respectively, and a reinforcing coating 50 formed on the outer peripheral surfaces of the upper core 31 and the lower core 41. The lower die 40 is fixed, and the upper die 30 is a movable die that is raised or lowered by an actuator 90. Thus, the joining and separating of the upper die 30 and the lower die 40 is performed by moving the upper die 30. The upper core 31 and the lower core 41 are formed on the mutually facing surfaces of the upper die 30 and the lower die 40 respectively, and when the molds are joined, cavities are formed so that the aspherical lens 20 can be molded. The number of cavities can be one or more, or two or more. The cavities are formed to correspond to the shape of the aspherical lens 20 to be manufactured. For example, the aspherical lens 20 can have a meniscus shape that convexes toward one or the other, or it can have a shape in which both surfaces are concave or convex. The upper core 31 protrudes upward from the lower surface of the upper mold 30. The upper core 31 includes a stepped portion 32 formed on its outer peripheral surface, allowing a step to be formed on one surface of the aspherical lens 20. The stepped portion 32 includes a horizontal surface 33 perpendicular to the vertical central axis of the upper core 31 and a vertical surface perpendicular to the horizontal surface 33, extending in an annular shape with a predetermined radius relative to the vertical central axis of the upper core 31. A plurality of stepped portions 32 are spaced apart from each other along the radial direction of the upper core 31. The lower core 41 is formed on the upper surface of the lower mold 40 facing the upper core 31 and is configured to receive the insertion of the upper core 31. Here, the upper core 31 formed on the movable upper mold 30 can be formed as a protruding protrusion, and the lower core 41 can be formed as a receiving groove configured to receive the protrusion. Alternatively, the shapes of the upper core 31 and the lower core 41 can be formed symmetrically. In this case, the upper core 31 and the lower core 41 are preferably formed of glassy carbon or a metallic material with excellent moldability. Glassy carbon is a carbon material with highly isotropic physical properties due to its chemical structure. It is significantly harder than graphite and has a shell-like fracture surface similar to glass. Furthermore, glassy carbon has very low permeability and is characterized by low dispersion of carbon particles. As described above, glassy carbon is classified as non-graphitizable carbon and is obtained by carbonizing thermosetting resins such as furan or phenolic resins. Since the molding die for aspherical lenses comprises an upper and lower core formed from a material with excellent moldability, wear of the grinding tools during die making can be prevented, thereby reducing the defect rate and increasing the service life of the grinding tools.

[0045] A reinforcing coating 50 is formed on the outer peripheral surfaces of the lower core 41 and the upper core 31 to enhance their hardness. The reinforcing coating 50 can be formed around the outer peripheral surfaces of the lower core 41 and the upper core 31 corresponding to the cavity. The reinforcing coating 50 enhances the strength of the lower core 41 and the upper core 31, thereby preventing wear or damage to the lower core 41 and the upper core 31 during the bonding of the upper mold 30 and the lower mold 40, and thus increasing the service life of the lower core 41 and the upper core 31. Furthermore, the temperature inside the cavity is maintained at the injection molding temperature described above, and the debonding and sintering processes are also performed at the aforementioned temperature. For this purpose, a heating unit including a temperature sensor (not shown) can be disposed outside the mold assembly, and the measured temperature can be controlled by a controller (not shown).

[0046] According to one embodiment of this disclosure, to manufacture a glass lens, glass particles, a polymer, and additives are mixed, and the mixture is injection molded. The polymer is then debonded and the glass material is sintered, thereby forming a lens shape. Furthermore, the material of the glass lens can be a material in which the polymer and glass particles are mixed, or a material containing glass particles with empty spaces from which the polymer has been removed. Additionally, the material of the glass lens can be a material in which glass particles are joined or fixed to each other by heat treatment, ultraviolet treatment, or extrusion. Although the mixed and extruded material includes glass particles, since the polymer exists in the spaces between the particles, the same or similar manufacturing process as that used for plastic materials can be used. Furthermore, the extruded mixture is injection molded into a lens shape using a die assembly, the polymer is removed by heat treatment, and the debonded lens is sintered near the glass transition temperature to remove polymer regions corresponding to the empty spaces and increase density. At this time, the glass particles transform into a slightly viscous state due to the high-temperature energy and bind to surrounding particles to fill the empty spaces. By removing the empty spaces between the particles and increasing density through sintering, the material becomes glass, and glass with a lens shape can be manufactured.

[0047] According to embodiments of this disclosure, since the lens is not manufactured through high-temperature glass molding or glass polishing, productivity can be increased and processing costs can be reduced. Furthermore, since injection molding, a common processing technique for plastic lenses, is utilized, restrictions on the machinable shape can be relaxed. Moreover, depending on the shape of the injection mold, the lens can have a spherical, aspherical, or free-form lens surface.

[0048] The features, structures, effects, etc., described in the above embodiments are included in at least one embodiment of this disclosure, and are not necessarily limited to one embodiment. Furthermore, the features, structures, and effects shown in each embodiment can be combined or modified by those skilled in the art relative to other embodiments. Therefore, the content related to these combinations and variations should be interpreted as being included within the scope of this disclosure. Although described based on embodiments, these are merely examples, and this disclosure is not limited thereto. It will be apparent to those skilled in the art that various modifications and applications not shown above are possible without departing from the basic characteristics of the embodiments. For example, each component specifically shown in the embodiments can be modified and implemented. And the differences associated with these modifications and applications should be interpreted as being included within the scope of this disclosure as defined in the appended claims.

Claims

1. A method for manufacturing an optical lens, comprising: The mixture is provided by mixing glass particles, a polymer filling the spaces between the glass particles, and additives; The mixture is injection molded using a mold assembly with a lens shape; The polymer is detached from the lens molded part that has been injection molded into the lens shape; The polymer is sintered from the glass particles in the molded part that have been removed from the molded part by debinding; as well as The sintered molded part is processed to provide a glass lens.

2. The method for manufacturing an optical lens according to claim 1, in, The temperature used for injection molding the molded part is lower than the temperature used for debinding the polymer.

3. The method for manufacturing an optical lens according to claim 1, in, The sintering temperature of the glass particles is higher than the temperature used to debind the polymer and the temperature used to injection mold the molded part.

4. The method for manufacturing an optical lens according to any one of claims 1 to 3, in, The glass particles comprise silicon dioxide particles, and The polymer includes thermoplastic resin materials.

5. The method for manufacturing an optical lens according to any one of claims 1 to 3, in, Each of the glass particles has a size of 800 nm or smaller, and The glass particles are mixed in a quantity of 70% or less relative to the mixture.

6. The method for manufacturing an optical lens according to any one of claims 1 to 3, in, Solvents used for debinding include at least one of distilled water, ethanol, and isopropanol.

7. The method for manufacturing an optical lens according to any one of claims 1 to 3, in, The sintering process is performed using low-voltage discharge plasma sintering.

8. The method for manufacturing an optical lens according to any one of claims 1 to 3, in, Mold components used for injection molding include shape-retaining mold materials.

9. An optical lens material, comprising: Glass particles; as well as A mixed material, filling the spaces between the glass particles and having a refractive index different from that of the glass particles, Each of the glass particles has a size of 800 nm or smaller, and The glass particles are mixed in an amount of 70% or less relative to the mixed material.

10. The optical lens material according to claim 9, in, The mixed material includes polymers or monomers that fill the spaces between the glass particles.

11. The optical lens material according to claim 9, in, The mixed material includes filling the empty spaces between the glass particles.

12. The optical lens material according to any one of claims 9 to 11, further comprising: An additive is configured to connect the glass particles and the mixed material.

13. The optical lens material according to any one of claims 9 to 11, in, The size of each glass particle is in the range of 50 nm to below 800 nm, and The glass particles are mixed in an amount ranging from 20% to 70% relative to the mixed material.

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