Glass lens, method for manufacturing glass lens, and optical system

Abstract

A method of manufacturing a glass lens disclosed in an embodiment of the present invention includes: providing a mixture by mixing glass particles, a polymer filled between the glass particles, and an additive; injection molding the mixture through a mold assembly having a lens shape; debinding the polymer from a lens-molded piece injection-molded into the lens shape; sintering the glass particles of the debound polymer-molded piece; and machining the sintered molded piece to be provided as a glass lens, wherein at least one of an object-side surface and an image-side surface of the glass lens can have an inflection point.

Description

Technical Field

[0001] Embodiments of the present invention relate to a glass lens and a method for manufacturing the glass lens. Embodiments of the present invention also relate to an optical system having a glass lens. Background Technology

[0002] Glass is a transparent, hard material with good thermal and chemical stability, making it suitable for various industries such as windows, solar panels, optical lenses, medical devices, and chemical and life science applications. Particularly in the field of optical lenses, glass offers advantages such as a wide range of refractive indices, low thermal expansion, and good durability, thus providing high applicability. When processing optical lenses made of glass, pressure is applied to the high-temperature glass to form the desired shape, or the glass is processed using a polishing machine. However, processing glass by melting it at approximately 1700 degrees Celsius affects the lifespan of the mold, and physical forming also presents many difficulties due to the high durability of glass. These conventional techniques are not suitable for large-scale production and involve high processing costs. Summary of the Invention

[0003] Technical issues

[0004] Embodiments of the present invention provide a glass lens comprising a material having a polymer and additives mixed with a glass material, and a method for manufacturing the glass lens. One embodiment of the present invention provides a method for manufacturing a glass lens, wherein the material having a polymer and additives mixed with a glass material is injection molded via a heat treatment process, the polymer is debonded from the molding material, and then a glass lens is formed. Embodiments of the present invention can provide an optical system having a glass lens with an inflection point.

[0005] Technical solution

[0006] A method for manufacturing a glass lens according to an embodiment of the present invention includes: mixing glass particles, a polymer filling between the glass particles, and additives to provide a mixture; injection molding the mixture through a mold assembly having a lens shape; debonding the polymer from the injection-molded lens part; sintering the glass particles in the debonded polymer part; and processing the sintered part to be provided as a glass lens, wherein at least one of the object-side surface and the image-side surface of the glass lens may have an inflection point.

[0007] According to embodiments of the present invention, the injection molding temperature for the molded part can be lower than the debinding temperature for the polymer. The sintering temperature of the glass particles can be higher than the debinding temperature of the polymer and the injection molding temperature of the molded part. The glass particles comprise silica particles, and the polymer can comprise a thermoplastic resin material. Each glass particle has a range of 10 nm to 500 nm, and the glass particles can be mixed in an amount of 40 wt% to 60 wt% relative to the blending material.

[0008] According to an embodiment of the invention, the mold assembly may have multiple gates, such that the mixture is injected into each of the multiple cavities inside the mold assembly.

[0009] According to embodiments of the present invention, a glass lens comprises glass particles; and the glass lens has a mixed material filled between the glass particles, the mixed material having a refractive index different from that of the glass particles, wherein at least one of the object-side surface and the image-side surface of the glass lens has an inflection point, and the glass lens may have cut surfaces disposed on mutually symmetrical outer sides. According to embodiments of the present invention, the number of cut surfaces may be 2 to 4.

[0010] An optical system according to an embodiment of the present invention includes a plurality of lenses aligned on an optical axis from an object toward an image sensor, wherein at least one of the object-side lens and the last lens is a glass lens disclosed above, and the glass lens may be positioned at a position closest to the image sensor or closest to the object.

[0011] Beneficial effects

[0012] According to embodiments of the present invention, since the injection molding method for plastic lenses is used to manufacture glass lenses, limitations on processing shapes can be reduced. Specifically, even at low temperatures, injection molding of glass lenses is possible, which can reduce manufacturing time, facilitate mass production, and lower production and processing costs. Furthermore, since the present invention manufactures glass lenses based on a plastic injection molding process, it has the advantage of facilitating the processing of inflection points, spherical surfaces, aspherical surfaces, and free shapes depending on the shape of the injection mold. Moreover, forming inflection points on the surface of the effective area of ​​the glass lens allows for modification of the optical path.

[0013] Because the glass lenses are injection molded, sintering time can be reduced. Specifically, since the process is performed using a low-voltage discharge plasma sintering method, the sintering time can be reduced to approximately 30 minutes. Therefore, this can help reduce the manufacturing cost of glass lenses and increase productivity.

[0014] Embodiments of the present invention can improve the price competitiveness of optical lens materials or glass lenses made therefrom, and can also improve the reliability of glass lenses. Embodiments of the present invention provide a glass lens with an inflection point, thereby improving the thermal and optical reliability of the optical system. Attached Figure Description

[0015] Figure 1 This is a schematic diagram illustrating a lens manufacturing process using glass material according to an embodiment of the present invention.

[0016] Figure 2 This is a diagram illustrating a lens manufacturing process using materials for glass lenses according to an embodiment of the present invention.

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

[0018] Figure 4 This is a diagram illustrating a process for manufacturing a glass lens using a mold assembly according to an embodiment of the present invention.

[0019] Figure 5 It is shown based on Figure 4 An example diagram of a manufactured glass lens.

[0020] Figure 6 This is an example of a side sectional view of a glass lens with an inflection point according to an embodiment of the present invention.

[0021] Figure 7 (A), (B), and (C) are shown Figure 6 A diagram illustrating an example of the manufacturing process for a glass lens.

[0022] Figure 8 (A) is based on Figure 7 A side sectional view of the manufactured glass lens, and Figure 8 (B) is an example of a fully manufactured glass lens.

[0023] Figure 9 (A) to Figure 9 (D) is a diagram showing an example of a glass lens with an inflection point.

[0024] Figure 10 (A) and (B) are examples of a core and valve connector with a single gate for manufacturing the glass lens of the present invention.

[0025] Figure 11 (A) and (B) are examples of core and valve connectors with multiple gates used in manufacturing the glass lens of the present invention.

[0026] Figure 12 This is an example of a core having multiple gates and multiple cavities used to manufacture the glass lens of the present invention.

[0027] Figure 13 This is an example of an optical system with a glass lens according to an embodiment of the present invention.

[0028] Figure 14 This is another example of an optical system with a glass lens according to an embodiment of the present invention.

[0029] Figure 15 This is a graph comparing the sintering time of the lens of the present invention and the lens of the comparative example. Detailed Implementation

[0030] Preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings.

[0031] The technical spirit of this invention is not limited to the embodiments described, and can be implemented in various other forms. One or more components can be selectively combined and substituted for use within the scope of the technical spirit of this invention. Furthermore, the terminology (including technical and scientific terms) used in the embodiments of this invention, unless explicitly defined and described, can be interpreted as having a meaning commonly understood by one of ordinary skill in the art to which this invention pertains, and commonly used terms, such as those defined in dictionaries, should be interpretable in light of the contextual meaning of the relevant art. Moreover, the terminology used in the embodiments of this invention is for illustrative purposes and is not intended to limit the invention. In this specification, unless specifically stated otherwise in the wording, the singular form may also include the plural form, and in the case of statements of at least one (or one or more) of A and / or B, C, it may include one or more of all combinations that can be combined with A, B, and C. In describing components of embodiments of this invention, 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 be determined by the nature, order, or process of the corresponding constituent elements. Furthermore, when describing a component as "connected," "joined," or "engaged" to another component, this description can include not only cases where the component is directly connected, joined, or engaged to another component, but also cases where the component is "connected," "joined," or "engaged" to another component through which it is connected. When described as being formed or disposed "above" or "below" each component, this description includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or disposed between the two components. Additionally, when expressed as "above" or "below," it can refer to both a downward and upward direction relative to a single element.

[0032] Figure 1 This diagram schematically illustrates a lens manufacturing process using glass material according to an embodiment of the present invention. Figure 2 This is a diagram illustrating a lens manufacturing process using materials for glass lenses according to an embodiment of the present invention. Figure 3 It is shown Figure 2 A flowchart of the manufacturing process of a glass lens. Figure 4 This is a diagram illustrating a process for manufacturing a glass lens using a mold assembly according to an embodiment of the present invention, and Figure 5 It is shown based on Figure 4 An example diagram of a manufactured glass lens.

[0033] Reference Figures 1 to 3 The material of the glass lens can be a mixture in which glass particles 110 are mixed with at least one other type of material. The material of the glass lens comprises a mixed material, and can be, for example, glass particles 110 and at least one polymer 120 or spaces where polymer 120 is removed. The mixed material can be a space having a refractive index different from that of the glass particles 110 or the plastic material, and can be a material in contact with the glass particles 110. The material of the glass lens can comprise a mixture of glass particles 110 and polymer 120, as well as additive 105. Additive 105 can be added for mixing and stabilizing the mixed material. The material of the glass lens can comprise a material in which the mixture is injection molded. The material of the glass lens can comprise a material in which the mixture is debonded or sintered after injection molding. Here, the material of the glass lens can comprise glass particles 110 and a material having spaces where polymer 120 is removed between the glass particles.

[0034] The manufacturing process of a glass lens may include the following steps: step S1, mixing glass particles 110, polymer 120, and additive 105; step S3, injection molding the material mixed in step S1 into a lens shape; and step S6, providing the glass lens after injection molding step S3. After injection molding step S3 and before setting the lens, the process may further include step S4, debinding at least one of polymer 120 and additive 105, and step S5, sintering the glass material molded part. Here, the temperature during injection molding may be a first temperature, the temperature during debinding may be a second temperature, and the temperature during sintering may be a third temperature. The first temperature may be lower than or higher than the second temperature, for example, lower than the second temperature. The third temperature may be higher than both the first and second temperatures. The first temperature is a temperature range used for plastic molding, and the third temperature may be a temperature range for glass transition.

[0035] 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 are transparent glass materials, and each particle has a width or diameter of less than 800 nm, and for example, can be in the range of 50 nm to 800 nm. Glass particles 110 can include spherical particles. As another example, 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, the variation in the shrinkage rate of the glass lens can be controlled or selected.

[0036] Glass materials can be based on silica particles (SiO2) for manufacturing lenses made of quartz materials. As another example, the particles can be applied to other transparent materials that determine the refractive index and Abbe number of the glass material. For instance, in the case of borosilicate glass lenses, the glass particles can contain particles with a composition of 80.6 wt% silica (SiO2), 13 wt% boron oxide (B2O3), 4 wt% sodium oxide (Na2O), and 2.3 wt% aluminum oxide (Al2O3). To manufacture glass lenses made of high-refractive-index materials, materials containing heavy metal oxides (such as lanthanum oxide (La2O3), titanium dioxide (TiO2), etc.) can be incorporated into the glass particles. Such glass materials can be applied not only to fused silica but also to materials with various refractive indices, such as soda lime glass, borosilicate glass, and aluminosilicate glass. Furthermore, the glass material can be applied to various transparent glass materials, such as glasses containing heavy metals and glasses with added oxides.

[0037] Polymer 120 may comprise a plastic material or a thermoplastic resin. Polymer 120 may be nanoscale particles smaller than the glass particles 110. As another example, polymer 120 may be provided in solution form. As another example, instead of polymer, monomer particles may be included. Polymer 120 may be particles or a solution smaller than the glass particles 110 to fill between the glass particles 110. The size of the glass particles may be below 500 nm, for example, from 10 nm to 500 nm.

[0038] The polymer 120 or monomer that fills the spaces between the glass particles 110 and bonds them together can be one or more types, for example, a mixture of multiple resins. The polymer or monomer fills the empty spaces between the glass particles and can then be further firmly fixed between the glass particles by a heat treatment or ultraviolet treatment process or an extrusion process (step S2). Because the polymer (or monomer) is present between the glass particles, the blended material can be set as a polymer, i.e., a plastic material, even if it includes glass particles. The polymer 120 or monomer may contain at least one of polyvinyl butyral, polyethylene glycol, 2-hydroxyethyl methacrylate, and 2-phenoxyethanol as a material capable of filling between the glass particles 110.

[0039] Additive 105 to the glass lens material may contain various materials, such as curing agents for polymerization and coupling agents for strong bonding between particles. Additive 105 may contain at least one of 2,2'-azobis(2-methylpropionitrile) and tetra(ethylene glycol) diacrylate. Regarding polymer 120 or the mixture, the content of glass particles 110 may be less than 70 wt%, for example, it may be mixed at 20 wt% to 70 wt% or 40 wt% to 60 wt%. 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 can be set by controlling the shrinkage rate of the final product, the isotropic nature of shrinkage, and defects during the debinding and sintering processes. After mixing, the material may also contain a liquid solvent, and the solvent may be removed in an oven process or at room temperature. Defects may occur during the debinding and sintering processes if materials other than the glass material are not dried or removed.

[0040] After extruding the mixture (S2), the extruded mixture 112 (see...) Figure 1 (S3) The plastic material is molded into lens-shaped injection molded parts 113A and 113B at a temperature equal to the injection molding temperature of the plastic material. Subsequently, through a debonding process S4 and a sintering process, the components present in the injection molded part 113 (see...) are... Figure 2 The polymer 120 in the ) is debonded by a debonding process, and the molded part 114 having empty spaces 120A of the polymer removed by the sintering process can be configured as a glass material lens molded part 115 in which there are no empty spaces (see Figure 2 ).

[0041] The sintered material from which polymer 120 is removed can be cut and processed into individual glass lenses. Additives can be removed during the aforementioned process. That is, when synthesizing the material for the glass lens, since polymer 120 exists in the spaces between the glass particles 110 within the material, an injection molding process to form a lens shape is performed at a temperature below 1700 degrees Celsius, which is the melting point of glass. Furthermore, the injection-molded material undergoes a debonding process at a temperature above 250 degrees Celsius (e.g., in the range of 250 to 700 degrees Celsius or 400 to 600 degrees Celsius). The debonding process is a process of removing the polymer between the formed glass particles. That is, polymer 120 can react with oxygen in the air at a temperature of approximately 300 degrees Celsius, removing gases containing carbon dioxide.

[0042] The material debonded from polymer 120 is formed into a lens shape by glass particles, at which point empty spaces exist in the space where polymer 120 has been removed. To remove these empty spaces, the part is sintered near the glass transition temperature. At this time, the glass particles are melted by high-temperature energy and transform into a state with slight viscosity, combining with surrounding particles to fill the empty spaces. Through this sintering process, as the empty spaces between the glass particles are removed and the density of the glass material increases, the material becomes glass and can be manufactured into a glass with a lens shape.

[0043] The following sections will describe specific injection molding processes, polymer debinding processes, and sintering processes.

[0044] <Injection Molding Process S3 for Mixtures>

[0045] Mixture 111 (see Figure 2 The monomers or polymers in the mixture are cured. At this point, the mixture can be cured using various methods such as light and heat, according to additive 105. Furthermore, due to the large shrinkage that occurs in the material after the debinding and sintering processes, the dimensions of the mixture to be injection molded can be mixed and extruded to larger dimensions, 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.

[0046] Conditions for injection molding of the mixture, such as injection pressure, time, and temperature, can be adjusted according to the polymer materials added to the mixture. For example, the injection pressure for molding injection-molded products 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, the injection conditions can be adjusted within a reasonable range, taking into account that the concentration of glass particles 110 (i.e., silica particles) in the mixture changes the viscosity and elasticity of polymer 120.

[0047] like Figure 4 As 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 metal material capable of injection molding glass material. The second core 102 may include a mold 103 having a second cavity R2 therein. The mold 103 may be made of metal and face the first core 101. The first core 101 includes a plurality of first cavities R1 spaced apart from each other in a region facing the mold 103, and the mold 103 may have second cavities R2 disposed in various regions facing the first cavities R1. The combined shape 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 in which one surface is concave and the other is concave; a shape in which one surface is concave and the other is convex; a shape in which one surface is convex and the other is convex; or a shape in which one surface is convex and the other is concave. One surface of the lens is an incident surface for light, and the other surface may be an exit surface for light. At least one of the surfaces may be spherical. As another example, at least one of the surfaces can be non-spherical.

[0048] One or more cavities for lenses can be provided within the first core 101 and the second core 102, but for increased productivity, eight or twelve cavities may be included. The first cavity R1 and the second cavity R2 can be arranged symmetrically, taking into account the injection speed and pressure of the mixture filling each cavity. A gate 105 is provided in the second core 102, and the gate 105 is configured to a size through which the nanoglass particles or the mixture can flow, and the mixture can be injected through the gate 105. For the inflow of the mixture, the flow path between the first core 101 and the second core 102 can have a size or diameter that does not affect the flowability of the nanoglass particles. When the mixture fills cavities R1 and R2, injection-molded parts 153 having lens shapes 151 and 152 can be provided. The injection-molded mixture is molded into a lens shape and has a shape in which the polymer is filled between the glass particles. At this time, lens shapes 151 and 152 can be connected to each other via connecting portions 154. Here, the first core 101 is a fixed portion, and the second core 102 can be a movable portion attached to or separate from the first core 101. In the extrusion process prior to injection molding, the mixture can be injected and pressure applied through the gate 105 to perform extrusion. As another example, the mixture can be placed in the lower cavity, and then pressure can be applied to the upper core to perform injection molding.

[0049] <Polymer Debinding Process S4>

[0050] The injection molding compound is molded into a lens shape with the polymer filling the spaces between glass particles. To extract pure glass material, a polymer debinding process S4 is performed to remove the polymer 120 present between the glass particles. Depending on the type, particle size, and chemical properties of the polymer present between the glass particles, the polymer debinding process S4 is performed after solvent debinding using a high-temperature debinding method. The solvent debinding method involves slowly dissolving the polymer 120 in a solvent to debind it. The solvent used for debinding may include at least one of distilled water (H₂O), ethanol (EtOH), and isopropanol (IPA), and may include all solvents that slowly dissolve the polymer 120. Furthermore, to efficiently perform debinding, the solvent debinding temperature may be below 50 degrees Celsius, for example, it may be carried out in a temperature range of 30 to 50 degrees Celsius, and the debinding time may be below 10 hours, for example, it may be performed for 1 to 10 hours depending on the type of polymer. Solvent debinding may be omitted to improve productivity efficiency depending on the type of polymer.

[0051] After solvent debinding, the injection molded product undergoes high-temperature debinding after the solvent has completely dried. This is because defects may occur in the injection molded product during the high-temperature debinding process when the solvent is retained, and the injection molded product may explode due to the sudden evaporation of the solvent. High-temperature debinding is a process of removing polymers between glass particles at high temperatures. Most polymers can react with oxygen in the air up to about 300 degrees Celsius and remove carbon dioxide gas. Furthermore, in order to completely remove organic materials from the injection molded product, high-temperature debinding is carried out at temperatures above about 500 degrees Celsius, for example, in the range of 500 to 700 degrees Celsius, and preferably, debinding can be carried out in the range of 550 to 650 degrees Celsius. Here, sudden temperature control during the heating of debinding can lead to defects in the injection molded product. For example, a rapid rise in temperature to the debinding temperature may cause strong flow of the polymer between the glass particles or generate a large amount of gas, which may lead to cracking. Therefore, the rate of temperature rise and fall from room temperature to the debinding temperature can be less than 20 degrees Celsius / minute, for example, in the range of 0.5 to 20 degrees Celsius / minute. The holding time at the debonding temperature can be less than 5 hours, for example, it can be in the range of 1 hour to 5 hours.

[0052] <Sintering process of the mixture S5>

[0053] The injection-molded product from which the polymer is debonded has a shape in which the polymer between the glass particles is removed and only the glass particles are retained. Since the empty spaces between the glass particles act as defects causing light scattering, the shape after debonding may be opaque even though only the glass particles are retained. Therefore, in order to remove the empty spaces in the injection-molded product and increase its density, a high-temperature sintering process S5 is performed. In the sintering process S5, the glass particles become glassy and the particles bond together. Thus, the empty spaces between the glass particles are filled to form a complete glass. During the sintering process, depending on the material of the glass particles, the sintering temperature can be below 1500 degrees Celsius, for example, in the range of 1000 to 1500 degrees Celsius. The sintering temperature can be determined near the glass transition temperature of the material, and for example, the sintering temperature for manufacturing quartz SiO2 lenses can be about 1300 degrees Celsius or in the range of 1250 to 1350 degrees Celsius.

[0054] Furthermore, the rate of temperature increase and decrease from room temperature to the sintering temperature can be less than 500 degrees / minute, for example, in the range of 5 degrees / minute to 500 degrees / 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. Moreover, when using pressureless discharge plasma sintering (PSS), the sintering time can be shortened to within 1 hour, and can be performed within 30 minutes, such as... Figure 7As shown in (A), and although this can vary depending on the material, manufacturing costs can be reduced and productivity can be increased because the sintering process is performed within 1 hour. Figure 7 The comparative example shown in (B) is sintered by an oven process, which takes about 10 hours. Therefore, productivity may be reduced and manufacturing costs may be increased.

[0055] During sintering, the degree of crystallinity of the glass can vary depending on the sintering temperature, holding time, and the rate of temperature increase and decrease. To manufacture transparent glass lenses, sintering conditions that suppress glass crystallization should be utilized. For example, the pressureless discharge plasma sintering conditions for manufacturing lenses made of quartz SiO2 material can be carried out at a temperature increase rate of 225 degrees per minute, held at 1300 degrees for 5 minutes, and a temperature decrease rate of 60 degrees per minute; these conditions can vary depending on the material of the glass particles. Since the empty spaces in the lens molding are removed during this sintering process S5, shrinkage of the injection-molded lens occurs. Although shrinkage correction is performed in the injection mold, isotropic shrinkage can be corrected by the surface shapes of the first core 101 and the second core 102 with shape-retaining metal during sintering, or by the surface shapes of the first core 101 and the mold 103. The shape-retaining metal maintains the shape of the injection-molded product during sintering and can induce isotropic shrinkage by uniformly transferring heat to the injection-molded product. One surface of the sintered lens is the incident surface of light, while the other surface can be the exit surface of light. At least one of the surfaces can be spherical. As another example, at least one of the surfaces can be non-spherical.

[0056] At least one of the surfaces of the first core 101 and the second core 102, and the surface of the mold 103, can be configured with a shape having an inflection point. In this case, the molded glass lens produced can have an inflection point. The refractive index of the glass lens can be 1.4 or higher, for example, in the range of 1.4 to 2.1 or in the range of 1.7 to 2.1.

[0057] like Figure 5As shown, the gate portion 153A retained in the molded part 153 having lens shapes 151, 152 is cut and can be manufactured into an injection-molded product of a single glass lens 150. The cutting of the gate portion 153A can include various methods, such as high-temperature cutting, laser cutting, ultrasonic cutting, etc., to minimize changes in the lens shape. The remaining connecting portion 154 after injection molding can be used to remove the polymer with a specific solvent to extract the glass material. That is, recycling of the glass particles is possible. Since the upper and lower cores of the molding die for the aspherical lens are formed of a material with excellent formability, there is an advantage in preventing wear of the grinding tools during mold manufacturing, thereby reducing the defect rate and increasing the service life of the grinding tools. A coating such as a mold coating can be formed on the surfaces of the first and second cores to prevent core wear or damage and increase core service life. Furthermore, the temperature in the cavity is maintained at the injection molding temperature disclosed above, and the debonding and sintering processes are also carried out at the temperature disclosed above. For this purpose, a heating element (not shown) with a temperature sensor (not shown) is provided outside the mold assembly, and the measured temperature can be adjusted by a control unit (not shown).

[0058] Reference Figures 6 to 8 The glass lens 250 can be formed from the glass material disclosed above. That is, the glass lens 250 is provided via injection molding using a composite material of polymer and glass particles, and can be configured as a glass lens of various shapes without limiting the surface shape of the lens. The size of the glass particles can be greater than 10 nm, for example, from 10 nm to 500 nm.

[0059] The glass lens 250 has an object-side surface S11 and an image-side surface S12. The object-side surface S11 is the surface opposite to the image-side surface S12 and is adjacent to the object. The image-side surface S12 is the surface opposite to the object-side surface S11 and is adjacent to the image sensor side. The center of the object-side surface S11 and the image-side surface S12 of the glass lens 250 is aligned with the optical axis OA. On the optical axis OA, the object-side surface S11 can be configured as convex, and the image-side surface S12 can be configured as concave. As another example, on the optical axis OA, the object-side surface S11 can be configured as concave, and the image-side surface S12 can be configured as convex. As another example, on the optical axis, both the object-side surface S11 and the image-side surface S12 can be configured as convex. As another example, on the optical axis, both the object-side surface S11 and the image-side surface S12 can be configured as concave.

[0060] The glass lens 250 may include an effective region and an ineffective region. The effective region can be the area through which incident light passes. That is, the effective region can be defined as the effective area or effective diameter where incident light is refracted to achieve optical properties. The ineffective region may be disposed around the effective region. The ineffective region can also be an area where effective light does not occur. That is, the ineffective region is an area unrelated to optical properties and can be defined as a flange portion. Furthermore, the end of the ineffective region may be a region fixed to a lens barrel (not shown) that houses one or more lenses. The outer surface S13 of the glass lens 250 may be configured as a vertical surface or an inclined surface and may contact the lens barrel. The lens 250 may be configured without an ineffective region.

[0061] At least one of the object-side surface S11 and image-side surface S12 of the glass lens 250 may have at least one inflection point between the optical axis and the end of the effective region. An inflection point may refer to a point where, based on the optical axis, the sign of the slope value changes from positive to negative or from negative to positive relative to a direction perpendicular to the optical axis, and may also refer to a point where the slope value is zero. Furthermore, an inflection point may be a point where the slope value of a tangent passing through the lens surface increases and then decreases or decreases and then increases. The object-side surface S11 of the glass lens 250 has a first inflection point, and the optical path traveling from the inner region between the optical axis and the first inflection point to the outer region between the first inflection point and the end of the effective region may be altered.

[0062] The image-side surface S12 of the glass lens 250 has a second inflection point, which can alter the optical path from the inner region between the optical axis and the second inflection point to the outer region between the second inflection point and the end of the effective region. Light incident on the inner region of the object-side surface S11 through the first inflection point P1 is refracted towards the optical axis, and light incident on the outer region can be refracted in a direction away from the optical axis. Furthermore, light transmitted through the second inflection point P2 to the inner region of the image-side surface S12 is refracted in the direction of the optical axis, and light incident on the outer region can be refracted in a direction away from the optical axis. Therefore, with the glass lens 250 having inflection points P1 and P2, the distance between two adjacent lenses can be adjusted, and the effective diameter of the sensor-side lens disposed on the sensor side relative to the glass lens 250 can be increased or decreased. Furthermore, the effective diameter of the object-side lens disposed on the object side relative to the glass lens 250 or the distance between lenses can be adjusted. The lens can be configured as a freeform surface lens in which the object-side surface S11 and / or the image-side surface S12 have inflection points. Therefore, the present invention can configure the object-side surface S11 or the image-side surface S12 to be convex or concave on the optical axis, and can have at least one inflection point P1 and P2.

[0063] Reference Figure 7 and Figure 8 Describe the manufacturing process of glass lenses. For example... Figure 7As shown in (A) and (B), the first core 201 and the second core 202 face each other, and then one of them is moved to make close contact. The first cavity R11 of the first core 201 has a first surface S21 corresponding to the shape of the object-side surface of the lens, and the second cavity R12 of the second core 202 has a second surface S22 corresponding to the shape of the image-side surface of the lens. The regions of the first cavity R11 and the second cavity R12 can be defined as the cavity R10 of the mold assembly. At least one or both of the first surface S21 and the second surface S22 can have inflection points. That is, an inflection point can be a point where a concave surface becomes a convex surface or a point where a convex surface becomes a concave surface.

[0064] When the first core 201 and the second core 202 are in close contact, gates 205 and 206 are provided. Gates 205 and 206 are connected to cavity R10 and can be configured as one or more. Multiple gates 205 and 206 can be arranged on opposite sides of cavity R10 or in positions symmetrical to each other, and in this case, the injection molding efficiency of glass lens material can be improved.

[0065] like Figure 7 As shown in (B) and (C), the glass lens material is injected into cavity R10 through gates 205 and 206. Gates 205 and 206 are set to a size through which nanoscale glass particles can flow or through which the mixture can flow, and the mixture can be injection molded through gates 205 and 206. An extrusion process prior to injection molding can be performed by injection molding the mixture and applying pressure through gates 205 and 206 to perform extrusion. When the glass lens material fills cavity R10, the material of glass lens 250A has a shape in which a polymer is filled between glass particles. The glass lens material extruded in injection molding ( Figure 3 After S3), the polymer debonds from the injection molding material. Figure 3 S4), and the sintered polymer debonded material ( Figure 3 (S5). After that, as... Figure 8 As shown in (A), the gate protrusions 251 and 252 retained in the gate portion of the sintered glass lens 250A are cut and removed, and as shown in (A). Figure 8 As shown in (B), a glass lens can be provided. Figure 3 (S6). Figure 3 Steps S3-S5 refer to the description disclosed above. The manufactured glass lens 250 may have a first inflection point on the object-side surface S11 and / or a second inflection point on the image-side surface S12. The positions of the first and second inflection points can be changed according to the optical design.

[0066] The glass lens 250 manufactured by the injection molding method disclosed above can have a diameter of 2 mm or more, for example, it can be in a shape from 2 mm to 100 mm or in a range from 2 mm to 40 mm. The minimum center thickness of the glass lens 250 can be 0.1 mm or more, for example, in a range from 0.1 mm to 5 mm. The edge thickness or flange thickness of the glass lens can be 0.1 mm or more, for example, in a range from 0.1 mm to 5 mm. The glass lens 250 manufactured by the injection molding method disclosed above can have a surface roughness of 5 nm or more, for example, in a range from 5 nm to 15 nm. The surface of the glass lens 250 can be polished by various methods such as sandpaper and slurry to further improve the surface roughness.

[0067] Various glass lens shapes can be provided based on the shape of the first core 201 and the second core 202 of the mold assembly and the shape of the cavity R10. For example... Figure 9 As shown in (A), the glass lens 230 can have a concave object-side surface S31 and a convex image-side surface S32 on the optical axis OA. The object-side surface S31 can have a first inflection point P3. Figure 9 As shown in (B), the glass lens 231 may have a concave object-side surface S33 on the optical axis OA, and may also have a concave image-side surface S34. The object-side surface S33 may have a first inflection point P5 adjacent to the edge rather than the optical axis OA. The image-side surface S34 may have a second inflection point P6 adjacent to the optical axis OA than the first inflection point P5. Figure 9 As shown in (C), the glass lens 232 may have a convex object-side surface S35 and a concave image-side surface S36 on the optical axis OA. The object-side surface S35 may have multiple inflection points, for example, inflection point P7A (1-1) and inflection point P7B (1-2). The image-side surface S36 may have a second inflection point P8. Inflection point P7A (1-1) may be located at a position corresponding to the second inflection point P8 in the optical axis direction, or it may be located closer to the optical axis OA.

[0068] like Figure 9 As shown in (D), the glass lens 233 may have a concave object-side surface S37 on the optical axis OA and a convex image-side surface S38. The object-side surface S37 may have an inflection point P9 adjacent to the optical axis OA. The image-side surface S38 may be configured to have no inflection point from the optical axis OA to the edge.

[0069] like Figure 10 As shown, a mold assembly 200 having a first core and a second core has a cavity 250B or lens region therein, and is connected to a single gate 212, which is connected to a supply valve 215 via a runner 211. Figure 11As shown, a mold assembly 200 having a first core and a second core has a cavity 250B or lens region therein and is connected to a plurality of gates 212, each of which is connected to a supply valve 215 via a runner 211. Each mold assembly 200 can be connected to the cavity 250B via two gates 212 located on opposite sides. Figure 12 As shown in (A) and (B), a plurality of mold assemblies 200 having a first core and a second core have cavities 250B or lens regions therein and are connected to a plurality of gates 212, each of the plurality of gates 212 being connected to a supply valve 215 via a runner 211. Each mold assembly 200 may be connected to the cavity 250B via four gates 212.

[0070] To uniformly distribute the glass particles and polymer into the cavity 250B, two, three, or more gates can be connected along the outer periphery of the cavity 250B. That is, one or more gates (e.g., one to eight gates) for forming the glass lens can be connected to the cavity 250B. The positions of the two or more gates can be arranged symmetrically or asymmetrically to ensure a uniform distribution of glass particles according to the lens shape. The diameter of the multiple gates 212 is adjusted according to the flowability of the raw material composite material, preferably including a range of 0.1 mm or more, for example, from 0.1 mm to 2 mm. Depending on the properties of the composite material, the shape of the gates 212 can include one of circular, square, rectangular, and trapezoidal shapes.

[0071] In the mold assembly for injection molding of glass lenses, gates such as annular gates, fan gates, side gates, overlapping gates, disc gates, edge gates, and pin-point gates can be used for uniform filling of glass particle powder. Considering the shrinkage of the glass lens product, open gates, valve gates, and semi-valve gates of hot runner systems can be used. Furthermore, a gate system with multiple mold assemblies can utilize multiple cavities, preferably four or more, for example, four to twenty-four cavities, to ensure uniform filling of the glass particle distribution. Additionally, the gate protrusions retained on the glass lens due to the gate can be removed from the lens by mechanical, chemical, or optical methods. For example, the removal of the gate protrusions can be physically performed by a high-temperature blade, by etching using chemicals, or by a high-power laser. After gate removal, the side surfaces of the lens (i.e., the cut surface shapes) can have various shapes, such as D-shaped cut shapes, double D-shaped cut shapes, and rectangular cut shapes. The number of multiple cut surfaces within the glass lens of the present invention can be 2 to 4. The number of cut surfaces can be equal to the number of gates. Typically, due to shrinkage during the injection molding of glass lenses, it is difficult to correct lens surfaces with inflection points, and therefore not easy to implement. This invention solves the above problems and can be configured as a glass lens with a lens surface having inflection points. Because this invention uses a polymer-glass particle composite material to form the glass lens shape through injection molding, it can be molded into various lens surfaces, such as inflection points, spherical surfaces, aspherical surfaces, spherical surfaces with inflection points, or aspherical surfaces with inflection points. Lenses made of glass materials exhibit less deformation with temperature and are used in high-reliability vehicle camera modules, military optics, precision microscopes, or telescopes. By providing glass material lenses of various shapes that are not possible to manufacture in the prior art, this invention can be applied to high-reliability, high-precision optical fields.

[0072] Figure 13 This is a diagram illustrating an example of an optical system having the glass lens of the present invention.

[0073] like Figure 13As shown, the optical system may include multiple lenses aligned along the optical axis OA from the object toward the image sensor 266. The multiple lenses may be three, four, or more than five. The multiple lenses may be a first lens 261, a second lens 262, a third lens 263, and a fourth lens 264. The first lens 261 is closest to the object and may have a convex object-side surface and a convex image-side surface along the optical axis OA. The second lens 262 is disposed between the first lens 261 and the third lens 263 and may have a concave object-side surface and a concave image-side surface along the optical axis OA. The third lens 263 is disposed between the second lens 262 and the fourth lens 264 and may have a convex object-side surface and a convex image-side surface along the optical axis OA. The object-side and image-side surfaces of the first lens 261, the second lens 262, and the third lens 263 may be arranged in different shapes. At least one or all of the first lens 261, the second lens 262, and the third lens 263 may be made of plastic or glass.

[0074] An aperture stop ST can be positioned around the area between the second lens 262 and the third lens 263. The aperture stop ST can adjust the amount of light incident on the third lens 263.

[0075] A fourth lens 264 can be disposed between the third lens 263 and the image sensor 266. The fourth lens 264 may include a convex object-side surface S41 and a concave image-side surface S42 on the optical axis OA. The object-side surface S41 may have a first inflection point P11, and the image-side surface S42 may have a second inflection point P12. The fourth lens 264 can refract light incident at inflection points P11 and P12 to the central and peripheral portions of the image sensor 266. Therefore, the resolution of the optical system can be improved.

[0076] The optical system may include an optical filter (not shown). The optical filter may be positioned between the fourth lens 264 and the image sensor 266. The optical filter may include an infrared filter or an infrared cutoff filter (IR cutoff). The optical filter may transmit light in a specified wavelength band and filter light in another wavelength band. When the optical filter includes an infrared filter, it can block radiative heat emitted from external light from being transferred to the image sensor 266. Furthermore, the optical filter may transmit visible light and reflect infrared light. The image sensor 266 can detect light passing sequentially through the lens. The image sensor 266 may include elements capable of detecting incident light, such as a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS).

[0077] Figure 14 This is a figure illustrating another example of an optical system having the glass lens of the present invention.

[0078] like Figure 14As shown, the optical system may include multiple lenses aligned along the optical axis OA from the object toward the image sensor 281. There may be more than five lenses, for example, five to fifteen. The multiple lenses may be a first lens 271 through a tenth lens 280.

[0079] The first lens 271 is closest to the object and may have a convex object-side surface and a concave image-side surface on the optical axis OA. The first lens 271 may be made of the glass material disclosed above. Because the first lens 271 is made of a material with high heat resistance, it is closest to the object and can suppress lens contraction or expansion caused by the external environment. This prevents optical axis shift and degradation of optical reliability. The object-side surface of the first lens 271 may have the largest effective diameter in the lens. At least one of the object-side surface and the image-side surface of the first lens 271 may have an inflection point.

[0080] The second lens 272 is disposed between the first lens 271 and the third lens 273, and may have a convex object-side surface and a concave image-side surface on the optical axis OA.

[0081] The third lens 273 and the fourth lens 274 can be cemented lenses. The object-side surface of the cemented lens can be convex, and the image-side surface can be flat or concave. The object-side surface of the fifth lens 275 can be convex, and the image-side surface can be flat, concave, or convex. The object-side surface of the sixth lens 276 can be convex, concave, or flat, and the image-side surface can be flat, concave, or convex. The sixth lens 276 can have the smallest effective diameter among the lenses. The seventh lens 277 and the eighth lens 278 can be joined together, and the object-side surface of the joined lens can be concave, and the image-side surface can be convex. The ninth lens 279 and the tenth lens 280 can be joined together, and the object-side surface of the joined lens can be convex, and the image-side surface can be convex. Except for the center distance between the cemented lenses, the center distance between the eighth lens 278 and the ninth lens 279 among adjacent lenses can be the smallest.

[0082] An aperture stop ST can be positioned around the region between the sixth lens 276 and the seventh lens 277. The aperture stop ST can adjust the amount of light incident on the seventh lens 277. The optical system may include an optical filter and / or a cover glass (not shown). The optical filter and cover glass can be positioned between the last lens and the image sensor 281. The diagonal length of the image sensor 281 can be greater than the effective diameter of the fifth lens 275 through the eighth lens 278.

[0083] Optical systems with such lenses can provide various camera modules, such as wide-angle, zoom, and smaller TTL, by increasing the degree of freedom in the shape of the glass lens. TTL is the distance from the center of the object-side surface of the first lens 261 to the optical axis of the image sensor 266. As this TTL increases, the size of the camera module may increase.

[0084] Embodiments of the present invention can manufacture glass lens shapes by mixing glass particles, polymers, and additives, performing injection molding of the mixture, debinding of the polymer, and sintering of the glass material. Furthermore, the material of the glass lens can be a mixture of polymer and glass particles, or a material of glass particles having empty spaces from which the polymer is 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 these mixed and extruded materials contain glass particles, since the polymer exists in the spaces between the particles, the same or similar manufacturing processes as those 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 debinded by heat treatment, and the debinded material is sintered near the glass transition temperature of the glass to remove the empty spaces that are polymer regions and increase density. At this time, the glass particles are transformed into a state with slight viscosity by high-temperature energy and combine with surrounding particles to fill the empty spaces. When the empty spaces between the particles are removed and the density is increased by sintering, the material becomes glass, and glass with a lens shape can be manufactured. Furthermore, glass lenses in which the object-side surface or image-side surface has an inflection point can be manufactured.

[0085] Embodiments of the present invention can improve productivity and reduce processing costs because the lenses are not manufactured through high-temperature glass molding or glass polishing. Furthermore, since injection molding, a common processing technique for plastic lenses, is utilized, the limitations on the processed shape become less restrictive. Moreover, depending on the shape of the injection mold, the lens can have inflection points, spherical surfaces, aspherical surfaces, and free-form lens surfaces.

[0086] The features, structures, effects, etc., described in the embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to one embodiment. Furthermore, the features, structures, effects, etc., shown in each embodiment can be combined or modified by those skilled in the art for other embodiments. Therefore, anything related to such combinations and modifications should be interpreted as being included within the scope of the present invention. Although embodiments have been described above, these are merely examples and do not limit the invention, and those skilled in the art have illustrated them without departing from the basic characteristics of these embodiments. It can be seen that various modifications and applications are possible. For example, the various components specifically shown in the embodiments can be implemented by modification. And the differences associated with these modifications and applications should be interpreted as being included within the scope of the invention as defined in the appended claims.

Claims

1. A method for manufacturing a glass lens, comprising: A 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; Debonding the polymer from the lens part that was injection molded into the lens shape; The glass particles of the molded part, after being debonded from the polymer, are sintered; and The sintered molded part is processed to be provided as a glass lens. At least one of the object-side surface and the image-side surface of the glass lens has an inflection point.

2. The method for manufacturing a glass lens according to claim 1, wherein, The injection molding temperature of the molded part is lower than the debonding temperature of the polymer.

3. The method for manufacturing a glass lens according to claim 1, wherein, The sintering temperature of the glass particles is higher than the debinding temperature of the polymer and the injection molding temperature of the molded part.

4. The method for manufacturing a glass lens according to any one of claims 1 to 3, wherein, The glass particles comprise silicon dioxide particles, and The polymer comprises thermoplastic resin material.

5. The method for manufacturing a glass lens according to any one of claims 1 to 3, wherein, Each of the glass particles has a diameter ranging from 10 nm to 500 nm, and The glass particles are mixed in an amount of 40 wt% to 60 wt% relative to the mixed material.

6. A method for manufacturing a glass lens according to any one of claims 1 to 3, wherein, The mold assembly has multiple gates to inject the mixture into the internal cavity.

7. The glass lens according to any one of claims 1 to 3, comprising: Glass particles; as well as A composite material, which fills the spaces between the glass particles and has a refractive index different from that of the glass particles, Wherein, at least one of the object-side surface and the image-side surface of the glass lens has an inflection point, and The glass lens has cut surfaces arranged on its outer sides that are symmetrical to each other.

8. The glass lens according to claim 7, wherein, The number of cut surfaces is in the range of 2 to 4.

9. An optical system, comprising: A plurality of lenses are aligned along the optical axis from the object toward the image sensor, wherein at least one of the object-side lens and the last lens is the glass lens as described in claim 7, and The glass lens is positioned closest to the image sensor or closest to the object.

Images