Optical prism, optical system, and method for manufacturing prism

Abstract

An optical system disclosed in an embodiment of the present invention may comprise: a lens unit having a plurality of lenses; and a prism disposed on at least one of an incident side and an emission side of the lens unit, wherein the prism may include an incident surface, an emission surface, and a reflective surface, the prism may include a concave groove along an outer edge of an effective area of the emission surface or the reflective surface, and a black coating layer disposed in the groove, and the black coating layer may be disposed on a region for blocking stray light inside the prism.

Description

Optical prism, optical system and prism manufacturing method

[0001] Embodiments of the invention relate to an optical prism and an optical system having the same. Embodiments of the invention relate to a prism and a method for manufacturing the same.

[0002] Prisms alter the path of light through refraction and total internal reflection, and are used in the optical systems of various optical devices such as cameras, microscopes, and telescopes. Demand for prisms has been increasing, with recent applications such as reducing the size of telephoto lenses in mobile cameras. However, conventional prism manufacturing methods, which rely on polishing and bonding, have low productivity and a high risk of defects during processing. Establishing an automated prism production process that considers the diversity of prism shapes, sizes, and facets presents limitations.

[0003] These prisms are used in various fields for optical processing of light, such as as optical components in folded cameras for smartphones and rear-view cameras for vehicles. The prisms are positioned and used to refract light incident on the camera module of a folded camera or rear-view camera and transmit it to the lens and image sensor.

[0004] Fig. 21 is a perspective view illustrating a conventional optical prism, and Fig. 22 is an exploded perspective view illustrating a bonding structure of a conventional optical prism. Referring to Figs. 21 and 22, a conventional optical prism (50) is manufactured into a single complete body by bonding multiple small-unit prisms (51, 52). However, the conventional technology has a problem in that the manufacturing cost is high because multiple molds are used to manufacture the small-unit prisms (51, 52) and then adhesive must be applied to the bonding surfaces (53) of each of the small-unit prisms (51, 52) to bond them together. In addition, due to the limitations of the bonding process, it is difficult to manufacture prisms with complex shapes, and there is a problem in that only simple shapes can be manufactured. In addition, since the small unit prisms (51, 52) of the prior art are manufactured into a finished prism through a post-process such as mutual bonding, there is a problem that a high level of bonding technology is required, and due to the limitations of the bonding technology, a bonding boundary (55) is inevitably created, and since the bonding boundary (55) is exposed to the outside, there is a problem that the appearance becomes poor.

[0005] In addition, the bonding method of bonding small unit prisms (51, 52) between surfaces requires a separate dedicated jig to be manufactured and aligned in order to match the adhesiveness between the two surfaces, and the bond application and curing processes must be performed simultaneously with the alignment process. However, since the alignment and curing processes must be performed for each small unit prism, there is a problem that the alignment of the bonding surfaces does not match for each lot of the product. Since the bonding method of the prior art is performed by exposing the bond to heat to harden it due to the nature of the bond, it can cause tilting of the lens due to shrinkage / expansion, and furthermore, there is a problem that the defect rate increases, such as the optical path of the optical prism deviating, by changing the refractive index of the prism surface, which reduces productivity.

[0006] Embodiments of the invention may provide an optical prism manufactured by at least one of injection molding, pressing, and casting processes, and a manufacturing method thereof. Furthermore, the manufactured prism may provide an integral prism shape without separate polishing, bonding, or cutting processes.

[0007] An embodiment of the invention can provide a prism and a method for manufacturing the same, which can control stray light inside the prism by forming a blackening coating film inside the prism.

[0008] An embodiment of the invention provides an optical prism and a method for manufacturing the same, in which multiple small-unit prisms are joined using a single mold by an overmolding method instead of a bonding method, so that a joining boundary is not formed, and thus the appearance is not only beautiful, but also the process can be simplified because the alignment between the small-unit prisms is naturally achieved during the joining process, and the problem of optical path deviation does not occur, so that a constant quality can be maintained. An embodiment of the invention provides an optical prism and a method for manufacturing the same, in which, by using an overmolding joining method, there are no restrictions on the shape, and thus optical prisms of various shapes with complex structures can be implemented, and since manufacturing is possible using a single mold, mold and manufacturing costs can be reduced.

[0009] An embodiment of the invention can provide an optical system having the prism disclosed above.

[0010] An optical system according to an embodiment of the invention comprises a lens unit having a plurality of lenses; and a prism disposed on at least one of an incident side and an exit side of the lens unit, wherein the prism includes an incident surface, an exit surface, and a reflective surface, and wherein the prism includes a concave groove along an outer edge of an effective area of ​​the exit surface or the reflective surface, and a blackening coating film disposed in the groove, wherein the blackening coating film can be disposed on an area that blocks stray light inside the prism.

[0011] According to an embodiment of the invention, the blackening coating film may include at least one of a black dye, a metal material, an organic light absorber, an inorganic black dye, or a carbon dye.

[0012] According to an embodiment of the invention, the grooves may be arranged along the upper and lower edges of the reflective surface in a direction perpendicular to the optical axes of the lenses.

[0013] According to an embodiment of the invention, the groove may be arranged along the upper edge and the lower edge of the exit surface in a direction perpendicular to the optical axis of the lenses.

[0014] According to an embodiment of the invention, at least one outer surface of the incident surface and the emission surface may have an anti-reflective coating layer or a low-reflective coating layer.

[0015] According to an embodiment of the invention, the outer surface of the reflective surface may have a mirror coating layer.

[0016] An optical prism according to an embodiment of the invention comprises: a prism having an incident surface, an exit surface, and a reflective surface, and arranged on at least one of an incident side and an exit side of a lens; a concave groove along an outer edge of an effective area of ​​the exit surface or the reflective surface of the prism; and a blackening coating film arranged in the groove, wherein the blackening coating film can be arranged on an area that blocks stray light inside the prism.

[0017] According to an embodiment of the invention, the blackening coating film may include at least one of a black dye, a metal material, an organic light absorber, an inorganic black dye, or a carbon dye.

[0018] According to an embodiment of the invention, the grooves may be arranged along the upper and lower edges of the reflective surface, respectively, in a direction perpendicular to the optical axes of the lenses. The grooves may be arranged along the upper and lower edges of the exit surface, respectively, in a direction perpendicular to the optical axes of the lenses. At least one outer surface of the entrance surface and the exit surface may have an anti-reflection coating layer or a low-reflection coating layer. The outer surface of the reflective surface may have a mirror coating layer.

[0019] According to an embodiment of the invention, the prism includes a first prism forming a first optical path, and at least one second prism forming a second optical path connected to the first optical path, and a portion of the second prism may be joined to one side of the first prism so as to overlap. The first prism may have a joining surface that is joined to the second prism, and a groove portion in which a portion of the second prism is joined to the joining surface.

[0020] A method for manufacturing an optical prism according to an embodiment of the invention may include the steps of manufacturing a prism shape using a liquid raw material casting, pressing, or injection equipment; the step of separating and then polishing the manufactured prism shape; the step of forming a groove through etching on at least one edge portion of an incident-side and an exit-side optical surface of the prism shape; and the step of forming a mirror coating on a reflective surface of the prism, an anti-reflection coating on the incident surface and the exit surface, and a blackening coating film on the groove using a coating material.

[0021] According to embodiments of the invention, prisms can be manufactured using casting, pressing, or injection molding methods using transparent materials, thereby increasing prism productivity and reducing processing costs. Furthermore, prisms can be manufactured using materials such as transparent plastic and glass. Furthermore, glass prisms can be manufactured by injection molding a mixture of polymer and glass particles, debinding, and sintering.

[0022] According to embodiments of the invention, since prisms of various shapes can be manufactured, total reflection through a specific critical angle can be achieved by controlling the optical path internally. Furthermore, control of the optical path through reflection through a mirror coating on the outside of the prism and total internal reflection can be achieved.

[0023] According to an embodiment of the invention, a blackening coating film can be integrally formed within the prism to improve the image quality of various optical devices such as cameras, microscopes, and telescopes utilizing prisms, and an optical system including such a prism can suppress the generation of stray light. This internal blackening coating film can be formed in various patterns to control stray light.

[0024] According to the invention, by joining multiple small-unit prisms by overmolding using a single mold instead of a bonding method, not only is the appearance beautiful because a joining boundary is not formed, but the alignment between the small-unit prisms is naturally achieved during the joining process, so the process can be simplified, and the problem of optical path deviation does not occur, so it has the effect of maintaining a constant quality. By using the overmolding joining method, the invention has no shape restrictions, so it can implement various forms of optical prisms with complex structures, and since manufacturing is possible using a single mold, it can reduce mold and manufacturing costs, and has the effect of excellent productivity.

[0025] Embodiments of the invention can increase the price competitiveness of an optical prism or a prism manufactured therefrom, and can improve the reliability of the prism and an optical system having the prism.

[0026] FIG. 1 is a drawing showing an optical system having an optical prism according to a first embodiment of the invention.

[0027] FIG. 2 is a drawing showing an optical system having an optical prism according to another example of the invention.

[0028] FIG. 3 (a)(b) is a perspective view and a side cross-sectional view showing an example of an optical prism according to the first embodiment of the invention.

[0029] Figures 4 (a)-(c) are drawings explaining the manufacturing process of the blackening coating film of the optical prism of Figure 3.

[0030] FIGS. 5(a)-(f) are examples of cross-sections of optical prisms having patterns of blackening coating films according to embodiments of the invention.

[0031] Figures 6 (A)-(D) are examples of side cross-sections of a blackening coating film according to an embodiment of the invention.

[0032] Figures 7 (a)-(e) are drawings showing shapes of optical prisms according to embodiments of the invention.

[0033] FIG. 8 is a drawing illustrating a first example of a manufacturing process of an optical prism according to an embodiment of the invention.

[0034] FIG. 9 is a drawing illustrating a second example of a manufacturing process of an optical prism according to an embodiment of the invention.

[0035] FIG. 10 is a drawing illustrating a third example of a manufacturing process of an optical prism according to an embodiment of the invention.

[0036] Fig. 11 is a flowchart showing a first example of a method for manufacturing an optical prism according to an embodiment of the invention.

[0037] Fig. 12 is a flowchart showing a second example of a method for manufacturing an optical prism according to an embodiment of the invention.

[0038] Fig. 13 is a flowchart showing a third example of a method for manufacturing an optical prism according to an embodiment of the invention.

[0039] Fig. 14 is a flowchart showing a fourth example of a method for manufacturing an optical prism according to an embodiment of the invention.

[0040] Fig. 15 is a perspective view illustrating an optical prism according to a second embodiment of the invention.

[0041] FIG. 16 is a perspective view showing a mold and a primary molding prism for manufacturing an optical prism according to a second embodiment of the invention.

[0042] Figure 17 is a process diagram sequentially illustrating an optical prism manufacturing process according to a second embodiment of the invention.

[0043] Fig. 18 is an exemplary drawing of forming a groove portion of a primary forming prism according to a second embodiment of the invention.

[0044] Fig. 19 is an exemplary diagram of forming a blackening coating pattern according to the second embodiment of the invention.

[0045] Fig. 20 is a flowchart showing a method for manufacturing an optical prism according to a second embodiment of the invention.

[0046] Fig. 21 is a perspective view illustrating a conventional optical prism.

[0047] Figure 22 is an exploded perspective view showing the bonding structure of a conventional optical prism.

[0048] Hereinafter, preferred embodiments of the invention will be described in detail with reference to the attached drawings.

[0049] The technical idea of ​​the invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the invention, one or more of the components between the embodiments can be selectively combined or substituted and used. In addition, the terms (including technical and scientific terms) used in the embodiments of the present invention can be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and the meaning of commonly used terms, such as terms defined in a dictionary, can be interpreted in consideration of the contextual meaning of the related technology. In addition, the terminology used in the embodiments of the present invention is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular may also include the plural unless specifically stated in the phrase, and when it is described as "A and (or at least one (or more than one) of B, C," it may include one or more of all combinations that can be combined with A, B, and C. In addition, when describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and the nature, order, or sequence of the components are not determined by the terms. In addition, when it is described that a component is 'connected', 'coupled', or 'connected' to another component, the component may include not only cases where the component is directly connected, coupled, or connected to the other component, but also cases where the component is 'connected', 'coupled', or 'connected' by another component between the component and the other component.Additionally, when it is described as being formed or arranged "above or below" each component, "above" or "below" 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 arranged between the two components. Furthermore, when it is expressed as "above" or "below", it can include the meaning of a downward direction as well as an upward direction based on one component.

[0050] FIG. 1 is a drawing showing an optical system having an optical prism according to an embodiment of the invention, FIG. 2 is a drawing showing an optical system having an optical prism according to another embodiment of the invention, FIG. 3a is a perspective view showing an example of an optical prism according to an embodiment of the invention, FIG. 3b is a drawing showing an example of a side cross-section of the optical prism of FIG. 3a, FIG. 4 (a) to (c) are drawings explaining a manufacturing process of a blackening coating film of the optical prism of FIG. 3, FIG. 5 (a) to (f) are examples of cross-sections of optical prisms having patterns of a blackening coating film according to an embodiment of the invention, and FIG. 6 (A) to (D) are examples of side cross-sections of a blackening coating film according to an embodiment of the invention.

[0051] Referring to FIG. 1, an optical system may include a prism (110), a lens unit (100) having a plurality of lenses, and an image sensing unit (130). The prism (110) may include an incident surface (S1), an exit surface (S2), and a reflective surface (S3). The incident surface (S1) and the exit surface (S2) of the prism (110) may be arranged on planes that are orthogonal to each other or at an angle of less than or greater than 90 degrees. The reflective surface (S3) of the prism (110) is arranged at an angle between the incident surface (S1) and the exit surface (S2), and may be arranged at an angle of, for example, 30 to 60 degrees or at an angle of 45 degrees. One or more reflective surfaces (S3) may be arranged in an area between the incident surface (S1) and the exit surface (S2) according to an incident path, a reflection path, or an exit path.

[0052] The above incident surface (S1) and the exit surface (S2) may have an anti-reflective coating or a low-reflective coating layer formed on the outer surface. In addition, the reflective surface (S3) may have a mirror coating layer formed on the outer surface.

[0053] The above lens unit (100) can refract light emitted through the prism (110) to the image sensor unit (130), and can include three or more lenses, for example, can have lenses in the range of three to twelve or three to nine lenses.

[0054] The image sensor unit (130) can detect incident light and convert it into an electrical signal. The image sensor unit (130) can detect light that has sequentially passed through the plurality of lenses, and can include any one of a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), a CPD, and a CID. The image sensor unit (130) can be an RGB (Red, Green, Blue) sensor for obtaining a color image. In addition, when the image sensor unit (130) is arranged in multiple numbers, it can include an RGB image sensor and a black and white image sensor.

[0055] The optical system may include an optical filter (not shown) disposed between the lens unit (100) and the image sensor unit (130). The optical filter may filter light corresponding to a specific wavelength range among light passing through the lens unit (100). The optical filter may be an infrared (IR) blocking filter that blocks infrared rays or an ultraviolet (UV) blocking filter that blocks ultraviolet rays. A cover glass (not shown) may be included between the optical filter and the image sensor unit (130). The cover glass may protect the image sensor unit (130). The camera module may be a camera for capturing RGB images or a camera for capturing RGB images and infrared images.

[0056] In addition, when the image sensor unit (130) is arranged in a direction perpendicular to the optical axis of the lens unit (100), a reflective prism (not shown) may be included between the image sensor unit (130) and the lens unit (100). The reflective prism may reflect light passing through the lens unit (100) toward the image sensor unit (130). The reflective prism may include a blackening coating film described later therein.

[0057] As shown in Fig. 1, the exit surface (S3) of the prism (110) has a groove (111) on the outer side of the effective area, and the groove (111) has a concave shape toward the inside from the exit surface (S3) and can extend in a direction perpendicular to the optical axis along the upper end and / or the lower end of the exit surface (S3). The groove (111) can be arranged at each of the upper end and the lower end of the exit surface (S3), and can be formed in an area capable of blocking stray light on the exit surface (S3). The upper end of the exit surface (S3) is a portion adjacent to the edge of the incident surface (S1), and the lower end is a portion adjacent to the lower edge of the reflective surface (S3). A blackening coating film (120) is arranged on the groove (111). The blackening coating film (120) may be made of a metallic or non-metallic material, and may be selected from materials such as black dye, metallic material, organic light absorber, inorganic black dye, and carbon dye. Specifically, when the blackening coating film (120) is made of a metallic material, it may include at least one of In, Ga, Zn, Sn, Al, Ca, Sr, Ba, W, U, Ni, Cu, Hg, Pb, Bi, Si, Ta, H, Fe, Co, Cr, Mn, Be, B, Mg, Nb, Mo, Cd, Sn, Zr, Sc, Ti, V, Eu, Gd, Er, Lu, Yb, Ru, Y, and La. The blackening coating film (120) may be an oxide material treated with black oxide or brown oxide.

[0058]

[0059] As shown in Fig. 2, the prism (110) includes a groove (112) at the upper end and / or lower end of the reflective surface (S3), and the groove (112) may be arranged at the outer edge of the effective reflection area of ​​the reflective surface (S3). The groove (112) has a concave shape toward the inside of the reflective surface (S3) and may extend in a direction perpendicular to the optical axis along the upper end and / or lower end of the reflective surface (S3). The groove (112) may be arranged at each of the upper end and lower end of the reflective surface (S3), and may be formed in an area capable of blocking stray light on the reflective surface (S3). The upper end of the reflective surface (S3) is a portion adjacent to the edge of the incident surface (S1), and the lower end is a portion adjacent to the lower edge of the exit surface (S2). A blackening coating film (120) is arranged in the groove (112). The above blackening coating film (120) may be made of a metallic or non-metallic material, for example, aluminum or copper, or plastic. The above blackening coating film (120) may be selected from the materials disclosed above.

[0060] As described above, by integrally providing a blackening coating film (120) on the outer side of the effective area of ​​the prism (110), the occurrence of stray light in the light path emitted through the prism (110) can be suppressed. Accordingly, the reliability of the optical system having the prism (110) can be improved.

[0061]

[0062] The prism (110) can be manufactured using a transparent material, and can be manufactured through, for example, casting, pressing, or injection molding methods. The transparent material may include transparent materials, glass, thermoplastic polymers, halogen minerals, etc., and the plastic material may be applied to various polymer materials such as polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), and polyamide. In addition, the raw material of the plastic material may be in a liquid or solid state. The production efficiency of the prism manufactured in this way can be increased, and the processing cost can be reduced.

[0063] The prism (110) may be formed by mixing transparent materials having different refractive indices. For example, a mixed material of a monomer or polymer and glass may be injection-molded into a glass material through injection molding, debinding, and sintering processes. Specifically, the injection material of the glass prism may further include a mixed material of glass particles and a polymer, and an additive for mixing and stabilizing the mixed material. That is, the prism material may include a material that is debinded or sintered after the mixture is injection-molded. Here, the prism material may include glass particles and a material having empty spaces between the glass particles from which the polymer has been removed. Thereafter, when the mixed material is injection-molded into a prism shape and provided as a prism, at least one of the polymer and the additive is debinded, and then the glass material molded product is sintered. Here, the temperature during the injection molding may be a first temperature, the temperature during the degreasing may be a second temperature, and the temperature during the sintering may be a third temperature. The first temperature may be lower or higher than the second temperature, for example, may be lower than the second temperature. The third temperature may be higher than the first and second temperatures. The first temperature may be a temperature range for plastic molding, and the third temperature may be a temperature range for glass transition.

[0064] The glass material can be used as a base for silica particles (SiO2) to manufacture a quartz material lens. As another example, the particles can be other transparent materials that can determine the refractive index and Abbe number of the glass material. For example, when applying a borosilicate glass lens, the glass particles can include a composition of 80.6 wt% silica (SiO2), 13 wt% boron oxide (B2O3), 4 wt% sodium oxide (Na2O), and 2.3 wt% alumina (Al2O3). In order to manufacture a glass lens of a high refractive index material, a material to which an oxidized heavy metal, such as lanthanum oxide (La2O3) or titanium dioxide (TiO2), is added can be included in the glass particles. The polymer can include a plastic material or a thermoplastic plastic resin. The polymer can be a nano-sized particle smaller than the glass particles. As another example, the polymer can be provided in the form of a solution. As another example, monomer particles may be included instead of the polymer. The polymer may be particles or a solution smaller than the glass particles so as to fill the spaces between the glass particles. The type of polymer or monomer that fills and connects the glass particles may be one or more, for example, a mixture of multiple types of resins. The polymer or monomer fills the empty spaces between the glass particles, and thereafter, a heat treatment or ultraviolet treatment process may be performed, or an extrusion process (S2) may be performed to more firmly fix the glass particles between the glass particles. Since the polymer (or monomer) exists between the glass particles, even if the glass particles are included, the mixed material can be provided as a polymer, i.e., a plastic material.The polymer or monomer may include at least one of polyvinyl butyral, polyethylene glycol, 2-hydroxyethyl methacrylate, and 2-phenoxyethanol to fill the spaces between the glass particles (110).

[0065] The additives of the above mixed material may include various materials such as a curing agent for polymerization and a linking agent for strong bonding between particles. The additive (105) may include at least one of 2,2'-Azobis(2-methylpropionitrile) and Tetra(ethylene glycol) diacrylate. Glass particles may be mixed in an amount or mass ratio of 70% or less, for example, 20 to 70%, with respect to the polymer or mixed material. That is, the mass ratio of the glass particles in the mixture may be equal to or less than the mass of the polymer. Conversely, the mass ratio of the glass particles in the mixture may be equal to or greater than the amount of the polymer. The content of the glass particles may be set by controlling the shrinkage rate of the final product, the isotropy of the shrinkage, and the defects in the debinding and sintering processes. After mixing, the material may further contain a liquid solvent, which may be removed during an oven process or at room temperature. If the solvent is not dried or removed, materials other than glass materials may cause defects during the degreasing and sintering processes.

[0066] When the above prism material is synthesized, a polymer exists in the spaces between the glass particles within the material, so that the injection molding process is performed in a lens shape at a temperature lower than the melting point of glass, 1700 degrees. In addition, the injection molded material undergoes a degreasing process at a temperature of 250 degrees or higher, for example, in the range of 250 to 700 degrees or 400 to 600 degrees. The degreasing process is a process of removing the polymer from between the molded glass particles. That is, the polymer can be removed as a gas containing carbon dioxide by reacting with oxygen in the air at about 300 degrees.

[0067] The polymer-degreased material has glass particles in a prism shape, and empty spaces exist in the spaces where the polymer is removed. To remove these empty spaces, the molded product is sintered near the transition temperature of the glass material. At this time, the glass particles are melted by high-temperature energy, transitioning to a slightly viscous state and combining 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 is increased, so the material becomes glassy and can be manufactured into glass with a prism shape. Here, the glass material is sintered at a temperature ranging from 1000 to 1400 degrees Celsius to remove the empty spaces and become a completely glassy material. The prisms manufactured in this way can have a wide range of refractive indices by processing various materials using injection, casting, or pressing methods, thereby increasing the degree of freedom of the optical path within the prism and allowing for application in various fields.

[0068]

[0069] As shown in (a)(b) of FIG. 3, the prism (110A) may be provided in a shape having a plurality of optical surfaces (S11-S16), for example, a hexahedron or any one of a hexahedron and an octahedron. The optical surfaces (S11-S16) may include at least one incident surface, at least another exit surface, and at least one effective reflective surface disposed on a surface between the incident surface and the exit surface. A first groove (113) is disposed on one edge of a first optical surface (S11) of the prism (110A), and a second groove (114) is disposed on the other edge of a second optical surface (S12) opposite to the first optical surface (S11). The first groove (113) extends in a long direction in the width direction (i.e., short-side direction) of the first optical surface (S11) and extends to the upper portions of the optical surfaces (S13, S14) on both sides of the first and second optical surfaces (S11, S12). The second groove (114) extends in a long direction in the width direction (i.e., short-side direction) of the second optical surface (S12) and extends to the lower portions of the optical surfaces (S13, S14) on both sides of the first and second optical surfaces (S11, S12).

[0070] The blackening coating film (120) disclosed above is disposed in the first and second grooves (113, 114). The blackening coating film (120) absorbs or blocks light that passes through or exits the effective area of ​​the first and second optical surfaces (S11, S12). The blackening coating film (120) may be selected from among the materials disclosed above.

[0071] As shown in Fig. 4, when the prism (110A) is manufactured, a process of forming grooves (113, 114) is performed, and the first groove (113) is etched in a groove shape extending from one edge of the first optical surface (S11) to the upper portions of both optical surfaces (S13, S14), and the second groove (114) is etched in a groove shape extending from one edge of the first optical surface (S11) to the upper portions of both optical surfaces (S13, S14). The etching process of the grooves (113, 114) can be selected from among laser, high-pressure water, chemical, physical etching, etc. A blackening coating film (120) can be formed in the grooves (113, 114) using a black dye, a metal material, an organic light absorber, an inorganic black dye, a carbon dye, etc. Since the prism (110A) has a black coating film (120) integrally formed inside, it can block the path of stray light generation inside the prism, thereby improving the quality of the optical device. The pattern shape of the grooves (113, 114) can be provided in various shapes to suppress stray light caused by diffraction, refraction, reflection, and scattering of light.

[0072] As shown in (a) of FIG. 5, a groove (113) is formed in the edge region of at least one of the incident surface, the exit surface, or the reflective surface of the prism (110), and the groove (113) may partially extend from the lower portion of the optical surface toward both edges, and a blackening coating film (120) may be formed on the surface or inside. As shown in (b) of FIG. 5, a groove (113) may be formed that partially extends along both edges from the upper portion of the optical surface on at least one of the incident surface, the exit surface, or the reflective surface of the prism (110), and a blackening coating film (120) may be formed. As shown in (c) of FIG. 5, a groove (113) that extends from the lower portion of the optical surface to the upper portion of one side may be formed on at least one of the incident surface, the exit surface, or the reflective surface of the prism (110), and a blackening coating film (120) may be formed. As shown in (d) of Fig. 5, a frame-shaped groove (113) arranged along the edge of the optical surface can be formed on at least one of the incident surface, the exit surface, or the reflective surface of the prism (110), and a blackening coating film (120) can be formed.

[0073] As shown in (e) of FIG. 5, a groove (113) partially extended along the upper and lower edges on one side of the optical surface may be formed on at least one of the incident surface, the exit surface, or the reflective surface of the prism (110), and a blackening coating film (120) may be formed. As shown in (f) of FIG. 5, a groove (113) partially extended along the upper and lower edges on the other side of the optical surface may be formed on at least one of the incident surface, the exit surface, or the reflective surface of the prism (110), and a blackening coating film (120) may be formed.

[0074] As shown in Fig. 6, the blackening coating film (120) and the grooves (113, 114) may include a concave-convex pattern in one direction. As shown in (A)(B) of Fig. 6, the blackening coating film (120) may have triangular patterns (R31) arranged regularly or irregularly, or square patterns (R32) arranged regularly or irregularly. As shown in (C)(D) of Fig. 6, the blackening coating film (120) may have hemispherical convex patterns (R33) arranged regularly or irregularly, or hemispherical concave patterns may be arranged between hemispherical convex patterns (R34). Based on Fig. 6, the patterns of the blackening coating film (120) may have a shape that protrudes toward the effective area or the optical axis. The patterns can block unnecessary light and control stray light. Additionally, the patterns of the blackening coating film (120) may be arranged in dense patterns in some areas and in small patterns in other areas. As another example, the patterns of the blackening coating film (120) may be arranged on the outer periphery.

[0075]

[0076] The shapes of the optical prisms can be provided as shown in (a) to (e) of Fig. 7. As shown in (a) of Fig. 7, the prism (110-1) is provided in a shape that becomes wider as it goes downward from the upper optical surface (S10), and both optical surfaces (S20) of the upper optical surface (S10) can be provided as inclined surfaces. As shown in Fig. 7 (b), the prism (110-2) is provided in a shape that becomes wider as it goes downward from the upper optical surface (S10), and at least one of one and the other optical surfaces of the upper optical surface (S10) can be inclined and the other can extend vertically. For example, one optical surface (S21) can be provided as an inclined surface, and the other optical surface can extend vertically.

[0077] As shown in (c) of Fig. 7, the upper optical surface (S10) of the prism (110-3) may have a shape in which the width becomes wider as it goes toward the center on both sides, and a shape in which the width becomes narrower as it goes from the center on both sides toward the lower optical surface. The optical surfaces (S22) on both sides of the upper optical surface (S1) may extend at an inclined angle from the center of the side toward the upper / lower sides. These side optical surfaces (S22) may be provided as internal total reflection surfaces. As shown in (e) of Fig. 7, the lower optical surface of the prism (110-4) may have a shape in which the width is wider than the upper optical surface (S10), and may have one optical surface (S23) having a surface that is perpendicular to the inclined surface from one side of the upper optical surface (S10), and the other optical surface that is perpendicular.

[0078] As shown in (f) of Fig. 7, the prism (110-5) may have a shape in which the width becomes wider as it goes toward the center on both sides from the upper optical surface (S10), and a shape in which the width becomes narrower as it goes from the center on both sides to the lower optical surface. The optical surfaces (S24) on both sides of the upper optical surface (S10) may extend in multiple stages at an inclined angle from the center of the side toward the upper / lower sides, for example, at least two side optical surfaces (S24) inclined toward the center of the side may be arranged on the upper optical surface (S10), and at least two side optical surfaces (S24) inclined toward the center of the side may be arranged on the lower optical surface. These side optical surfaces (S23) may be provided as total internal reflection surfaces.

[0079] As described above, the size of the polyhedral-shaped prism may be 1 mm or more, for example, in the range of 1 mm to 50 mm or in the range of 3 mm to 25 mm. The prism may include at least one or both of a structure that provides a reflective surface through a mirror coating on the outside and a structure that changes the light path through total internal reflection.

[0080]

[0081] Fig. 8 is an example of a casting method of a prism according to an embodiment of the invention. As shown in Fig. 8, a casting space (202) is provided between an upper frame (201) and a lower frame (202), and an injection port (203) is formed on one side. In this structure, a casting material (210) of a transparent liquid raw material is filled into the casting space (202) through the injection port (203) on one side. Thereafter, the liquid material is hardened, and the upper frame (201) and the lower frame (202) are separated to form a prism (210), and the gate protrusion formed on the prism (210) can be removed.

[0082] Fig. 9 is an example of a method for pressing a prism according to an embodiment of the invention. As shown in Fig. 9, the upper press (211) and the lower press (212) are provided with mold spaces (211A, 212A), and after dispensing a transparent liquid raw material into the lower mold space (212A), the upper press (211) is pressed so that the liquid material is formed into the shape of a prism (220), the liquid material is hardened, and then the upper press (211) is separated to provide a prism.

[0083] Fig. 10 is an example of a method for injection molding a prism according to an embodiment of the invention. As shown in Fig. 10, mold spaces (223A, 223B) are provided inside the upper frame (221) and the lower frame (222), and the shape of the prism grooves (223A, 223B) is a prism shape and can be connected to the grooves (223A, 223B) through an injection port (225) inside the lower frame (222). A transparent liquid material is injected through the injection port (225) and then filled into the prism grooves (223A, 223B). Thereafter, after curing, the lower frame (222) is separated, and a prism-shaped structure (230) is manufactured. The prism-shaped structure (230) can be manufactured into individual prisms by cutting the prisms so that the prisms can be connected to each other by an intermediate connecting portion (230B).

[0084]

[0085] The casting process of the prism will be described in detail with reference to FIG. 11. Referring to FIG. 11 and FIG. 8, a liquid raw material is injected into the mold space (202) of the prism between the upper and lower frames (201, 202) (steps 11, 12). Thereafter, the raw material in the shape of a prism is hardened, cooled, and separated (step 13). Thereafter, the prism shape is polished (step 14), and an etching process is performed to form a groove for an internal blackening coating (step 15). Thereafter, a coating material or object is inserted (step 16), and a mirror coating is performed on the reflective surface using the coating material (step 17), an external black coating, i.e., a blackening coating film, is formed in the groove (step 18), and an anti-reflection coating or an anti-reflection (AR) coating layer can be formed on the incident surface and / or the exit surface (step 19). Here, the order of steps 17 to 19 may be changed.

[0086] The detailed pressing process of the prism will be described with reference to FIG. 12. Referring to FIG. 12 and FIG. 9, a liquid raw material made of glass is injected into the mold space (211A, 212A) of the prism arranged between the upper and lower presses (211, 212) and pressed (steps 21-23). ​​Thereafter, the raw material in the shape of a prism is hardened and then polished (step 24). Thereafter, an etching process is performed to form a groove for internal coating (step 25). Thereafter, a coating material or object is inserted (step 26), and a mirror coating is performed on the reflective surface using the coating material (step 27), and an external black coating, i.e., a blackening coating film, is formed in the groove (step 28). A low-reflection coating or an anti-reflection (AR) coating layer can be formed on the incident surface and / or the exit surface (step 29).

[0087] The injection molding process of the prism will be described in detail with reference to FIG. 13. Referring to FIG. 13 and FIG. 10, a liquid raw material made of plastic is injected into the mold space of the prism placed between the upper frame (221) and the lower frame (223) and injected (steps 31 and 32). Thereafter, the injected prism shape is separated and then polished (step 33). Thereafter, an etching process is performed to form a groove for internal coating (step 34). Thereafter, a coating material or object is inserted (step 35), and a mirror coating is performed on the reflective surface using the coating material (step 36), and an external black coating, i.e., a blackening coating film, is formed in the groove (step 37). A low-reflection coating or an anti-reflection (AR) coating layer can be formed on the incident surface and / or the exit surface (step 38).

[0088] The injection molding process of the prism will be described in detail with reference to FIG. 14. Referring to FIG. 14 and FIG. 10, a liquid raw material mixed with polymer and glass is injected into the mold space (223A, 223B) of the prism placed between the upper and lower molds (221, 223) and injected (steps 41, 42). Afterwards, a degreasing and sintering process is performed (step 43), and the injected prism shape is separated and then polished (step 44). Afterwards, an etching process is performed to form a groove for internal coating (step 45). Afterwards, a coating material or object is inserted (step 46), and a mirror coating is performed on the reflective surface using the coating material (step 47), and an external black coating, i.e., a blackening coating film, is formed in the groove (step 48). A low-reflection coating or an anti-reflection (AR) coating layer can be formed on the incident surface and / or the exit surface (step 49).

[0089]

[0090] FIG. 15 is a perspective view illustrating an optical prism according to a second embodiment of the invention, FIG. 16 is a perspective view illustrating a mold and a primary molded prism for manufacturing an optical prism according to the second embodiment of the invention, and FIG. 17 is a process diagram sequentially illustrating a manufacturing process of an optical prism according to the second embodiment of the invention.

[0091] Referring to FIGS. 15 to 17, an optical prism (60) according to a second embodiment of the invention can be formed as a finished product by overmolding a secondary molding prism (62) based on a primary molding prism (61). As shown in FIG. 15, the primary molding prism (61) can form a first optical path. The first optical path can form an input path through which an optical signal is input, a refractive path through which the input optical signal is refracted, and an output path through which the optical signal is output. At this time, the input path and the output path can be formed on the same surface or on surfaces in different axial directions, respectively. In addition, the surface forming the input path and the output path can be a bonding surface (61A) through which the secondary molding prism (62) is bonded to the primary molding prism (61). The first and second optical paths have a path that passes through an effective area within the prism or reflects into an effective area. The above primary forming prism may be a first prism or a main prism, and the above secondary forming prism may be a second prism or a sub-prism. The second prism may be joined or bonded to one or more sides or both sides of the first prism, one or more. Any one of the second prism or the plurality of second prisms may be arranged on the incident side or the output side of the lens.

[0092] The secondary forming prism (62) can form a second optical path connected to the first optical path. In addition, the secondary forming prism (62) can be formed as a single body or can be formed by joining a plurality of single bodies in a separate form to the primary forming prism (61). In this case, the plurality of secondary forming prisms (62) can be joined to the same joining surface (61A) of the primary forming prism (61), or can be joined to joining surfaces (61A) in different axial directions, respectively. The primary forming prism (61) can form at least one joining surface (61A). As shown in Fig. 16, the secondary forming prism (62) can be formed by overmolding in a mold (70) based on the primary forming prism (61). That is, one or a portion of a plurality of second prisms (62) can be joined or joined to overlap based on the first prism (61). Here, the overlapping region is a region that does not affect the optical path, and can be overlapped in a direction orthogonal to the optical path, i.e., in a vertical direction.

[0093] Referring to Fig. 16, a mold (70) is disclosed. The mold (70) may be composed of an upper mold and a lower mold, and the lower mold is disclosed in Fig. 16. The mold (70) may be divided into a first region (71) and a second region (72). The boundaries according to the divisions are not visible to the naked eye, and the first region (71) into which the primary forming prism (61) is inserted may be divided, and the remainder excluding the inserted primary forming prism (61) may be divided into a second region (72). The second region (72) may be one or more divided regions, and may be in a form that surrounds at least one surface of the primary forming prism (61).

[0094] The mold (70) may have an injection path formed to inject molten material from the outside into the second region (72). The primary molding prism (61) may form at least one bonding surface (61A) that is in contact with the secondary molding prism (62). The primary molding prism (61) is pre-inserted into the mold (70) to occupy a certain area (the first area) within the mold (70), and the remaining area (the second area) excluding the primary molding prism (61) is filled with molten material, and as it hardens, the secondary molding prism (62) may be completed in the form of an overmolding bond with the primary molding prism (61). At this time, the molten material may be the same material as the primary molding prism (61). The molten material may be a synthetic resin-based or glass (quartz)-based material used as a raw material for optical products.

[0095] The process of manufacturing an optical prism (60) will be described with reference to Fig. 17. Referring to Fig. 17, a primary molding prism (61) is inserted into a prepared mold (70). At this time, the mold (70) is formed with a first region (71) having the same shape as the primary molding prism (61), and the primary molding prism (61) can be inserted into the first region (71). A molten material is injected into the mold (70) into which the primary molding prism (61) is inserted, and fills the second region (72), which is the remaining region excluding the primary molding prism (61). The molten material filled in the second region (72) is hardened in a state of contacting the primary molding prism (61) with at least one bonding surface (61A), so that the secondary molding prism (62) can be completed. At this time, the first molding prism (61) and the second molding prism (62) are joined by the viscosity of the molten material itself. For example, since the molten material is the same material as the first molding prism (61), a melting bond is formed between the materials at the joining surface, which allows the first molding prism (61) and the second molding prism (62) to have an integrity close to that of a single molded product.

[0096] The first molded prism (61) and the second molded prism (62) that have undergone the hardening process can be taken out of the mold (70) in a complete form and provided as an optical prism (60). At this time, the first molded prism (61) before being inserted into the mold (70) may have a groove (61C) and a blackening coating pattern (65) formed thereon. The groove (61C) can provide a means for improving the bonding strength between the first molded prism (61) and the second molded prism (62), and the blackening coating pattern (65) can provide a means for controlling stray light that affects the optical path of the optical prism (60).

[0097]

[0098] Fig. 18 is an exemplary diagram for forming a groove portion of a primary forming prism according to a second embodiment of the invention. Referring to Fig. 18, a groove portion (61C) may be formed on the bonding surface of the primary forming prism (61) so that a portion of a secondary forming prism (62) may be injected. The groove portions (61C) may be formed in at least two locations, and the groove portions (61C) may be formed outside the optical path so as not to interfere with the optical path. By forming the groove portions (61C) at the corners of the bonding surface (61A), interference with the optical path can be avoided. A plurality of secondary forming prisms or second prisms may be combined or joined to the primary forming prism or the first prism. That is, a plurality of second prisms may be arranged on one side of the first prism, or on both sides of the first prism. The above plurality of second prisms may include a prism that is joined in a direction from the upper surface to the lower surface on one side of the first prism, and a prism that is joined in a direction from the lower surface to the upper surface.

[0099] Figures 18 (a)-(d) illustrate examples of forming various shapes of grooves (61C) and a state in which a secondary forming prism (62) is combined. The grooves (61C) may have any one shape among shapes such as a square, a triangle, an inverted triangle, a semicircle, a T-shape, a folded shape (e.g., an L-shape), or a combination thereof.

[0100] FIG. 19 is an exemplary diagram for forming a blackening coating pattern according to a second embodiment of the invention. Referring to (a) to (e) of FIG. 19, a blackening coating pattern (65) may be formed on the bonding surface (61A) of the primary forming prism. The blackening coating pattern (65) may be formed on an outer portion or periphery that does not interfere with the optical path. The blackening coating pattern (65) is formed in a band shape along the edge of the bonding surface (61A), and may avoid interference with the optical path. The blackening coating pattern (65) may be formed so as not to overlap with the groove portion (61C) of FIG. 18, or may be formed so as to overlap with the groove portion (61C) in a portion thereof. The blackening coating pattern is a blackening coating film, and the blackening coating film may include at least one of a black dye, a metal material, an organic light absorber, an inorganic black dye, or a carbon dye.

[0101]

[0102] Fig. 20 is a flowchart showing a method for manufacturing an optical prism according to a second embodiment of the invention. Referring to Fig. 20, the method for manufacturing an optical prism according to an embodiment of the invention may include a step (S61) of inserting the first molded prism (61) into a first region (71) of a mold (70); a step (S62) of injecting a molten material into a second region (72) of the mold (70) in an empty state to over-mold the second molded prism (62); and a step (S63) of removing the over-molded optical prism (60) from the mold (70). The first molded prism (61) may be inserted so that the joint surface (61A) is open to the second region (72). The above-mentioned primary forming prism (61) can form at least one bonding surface (61A) that is in contact with the secondary forming prism (62), and a groove (61C) can be formed in the bonding surface (61A) so that a part of the secondary forming prism (62) is injected. The groove (61C) can be formed outside the optical path so as not to interfere with the optical path.

[0103] A blackening coating pattern (65) is formed on the above-described bonding surface (61A), and the blackening coating pattern (65) can be formed outside the optical path so as not to interfere with the optical path. According to the prism of the present invention and the manufacturing method thereof as described above, since multiple small-unit prisms are bonded by overmolding using a single mold instead of a bonding method, a bonding boundary is not formed, so not only is the appearance beautiful, but also the alignment between the small-unit prisms is naturally achieved during the bonding process, so the process can be simplified, and there is an advantage in that a problem of optical path deviation does not occur, so a constant quality can be maintained. Since the invention uses the overmolding bonding method, there are no restrictions on the shape, so optical prisms of various shapes with complex structures can be implemented, and since manufacturing is possible using a single mold, mold and manufacturing costs can be reduced, and there is an advantage in that productivity is excellent.

[0104] Embodiments of the invention can manufacture prisms using glass or plastic materials using various manufacturing methods, thereby providing prisms of various polyhedral shapes, and enabling light path control through total internal reflection. In addition, by integrally arranging a blackening coating film in an area inside the prism to block stray light, stray light control can be effectively achieved. Furthermore, the invention can provide a technology for manufacturing prisms using various materials, such as quartz and fused silica, without being limited to plastic materials, by utilizing injection molding, casting, and pressing equipment. Alternatively, glass or ceramic prisms manufactured through injection molding, casting, and pressing are manufactured using a raw material that mixes polymer and glass particles, and can provide a prism made of perfect glass after a degreasing and sintering process. Prisms utilizing various materials, such as glass and plastic, can easily control the light path through differences in refractive index, and can provide prisms with high usability in optical devices. Therefore, the blackening coating inside the prism can control stray light caused by multiple reflective surfaces or combined optical devices, thereby providing improved optical and image quality.

[0105]

[0106] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified and implemented in other embodiments by a person having ordinary skill in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention. In addition, although the embodiments have been described above, these are merely examples and do not limit the present invention. Those having ordinary skill in the art to which the present invention pertains will appreciate that various modifications and applications not illustrated above are possible without departing from the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments can be implemented by modification. And the differences related to such modifications and applications should be interpreted as being included in the scope of the present invention defined in the appended claims.

Claims

1. A lens unit having multiple lenses; and It includes a prism arranged on at least one of the incident side and the incident side of the lens unit, The above prism includes an incident surface, an exit surface, and a reflecting surface, The above prism includes a concave groove along the outer edge of the effective area of ​​the emission surface or the reflection surface, and a blackening coating film disposed in the groove, An optical system in which the blackening coating film is disposed on an area that blocks stray light inside the prism.

2. In paragraph 1, An optical system wherein the blackening coating film comprises at least one of a black dye, a metal material, an organic light absorber, an inorganic black dye, or a carbon dye.

3. In paragraph 1, An optical system wherein the grooves are arranged along the upper and lower edges of the reflective surface in a direction perpendicular to the optical axes of the lenses.

4. In paragraph 1, An optical system wherein the above grooves are arranged along the upper and lower edges of the exit surface in a direction perpendicular to the optical axes of the lenses.

5. In any one of paragraphs 1 to 4, An optical system, wherein at least one outer surface of the incident surface and the exit surface has an anti-reflective coating layer or a low-reflective coating layer.

6. In any one of paragraphs 1 to 4, An optical system in which the outer surface of the above reflective surface has a mirror coating layer.

7. A prism having an incident surface, an exit surface, and a reflective surface, and arranged on at least one of the incident side and the exit side of the lens; A concave groove along the outer edge of the effective area of ​​the emission surface or reflective surface of the prism; and Includes a black coating film placed on the above home, An optical prism, wherein the blackening coating film is disposed on an area that blocks stray light inside the prism.

8. In paragraph 7, An optical prism, wherein the blackening coating film comprises at least one of a black dye, a metal material, an organic light absorber, an inorganic black dye, or a carbon dye.

9. In paragraph 7, An optical prism, wherein the grooves are respectively arranged along the upper and lower edges of the reflective surface in a direction perpendicular to the optical axes of the lenses.

10. In paragraph 7, An optical prism, wherein the grooves are respectively arranged along the upper and lower edges of the exit surface in a direction perpendicular to the optical axes of the lenses.

11. In any one of paragraphs 7 to 10, An optical prism, wherein at least one outer surface of the incident surface and the exit surface has an anti-reflective coating layer or a low-reflective coating layer.

12. In paragraph 11, An optical prism having an outer surface of the above reflective surface having a mirror coating layer.

13. In any one of paragraphs 7 to 10, The prism comprises a first prism forming a first optical path, and at least one second prism forming a second optical path connected to the first optical path, An optical prism in which a portion of the second prism is overlapped and joined to one side of the first prism.

14. In paragraph 13, An optical prism in which the first prism has a bonding surface that is bonded to the second prism, and a groove portion in which a part of the second prism is joined to the bonding surface.

15. A step of manufacturing a prism shape using a liquid raw material casting, pressing, or injection equipment; A step of separating and polishing the manufactured prism shape; A step of forming a groove through etching on at least one edge portion of the incident side and the output side optical surface of the prism shape; and A method for manufacturing an optical prism, comprising the steps of forming a mirror coating on the reflective surface of the prism, a low-reflection coating on the incident surface and the exit surface, and a blackening coating film on the groove using a coating material.

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